Cumulative lead exposure in community-dwelling adults and fine motor function: comparing standard and novel tasks in the VA Normative Aging Study

PubMed Central

Grashow, Rachel; Spiro, Avron; Taylor, Kathryn M.; Newton, Kimberly; Shrairman, Ruth; Landau, Alexander; Sparrow, David; Hu, Howard; Weisskopf, Marc

2013-01-01

Background and Aims Lead exposure in children and occupationally-exposed adults has been associated with reduced visuomotor and fine motor function. However, associations in environmentally-exposed adults remain relatively unexplored. To address this, we examined the association between cumulative lead exposure—as measured by lead in bone—and performance on the Grooved Pegboard (GP) manual dexterity task, as well as on handwriting tasks using a novel assessment approach, among men in the VA Normative Aging Study (NAS). Methods GP testing was done with 362 NAS participants, and handwriting assessment with 328, who also had tibia and patella lead measurements made with K-X-Ray Fluorescence (KXRF). GP scores were time (sec) to complete the task with the dominant hand. The handwriting assessment approach assessed the production of signature and cursive lowercase l and m letter samples. Signature and lm task scores reflect consistency in repeated trials. We used linear regression to estimate associations and 95% confidence intervals (CI) with adjustment for age, smoking, education, income and computer experience. A backward elimination algorithm was used in the subset with both GP and handwriting assessment to identify variables predictive of each outcome. Results The mean (SD) participant age was 69.1 (7.2) years; mean patella and tibia concentrations were 25.0 (20.7) μg/g and 19.2 (14.6) μg/g, respectively. In multivariable-adjusted analyses, GP performance was associated with tibia (β per 15 μg/g bone = 4.66, 95% CI: 1.73, 7.58, p=0.002) and patella (β per 20 μg/g = 3.93, 95% CI: 1.11, 6.76, p = 0.006). In multivariable adjusted models of handwriting production, only the lm-pattern task showed a significant association with tibia (β per 15 μg/g bone = 1.27, 95% CI: 0.24, 2.29, p = 0.015), such that lm pattern production was more stable with increasing lead exposure. GP and handwriting scores were differentially sensitive to education, smoking, computer

Childhood poverty and health: cumulative risk exposure and stress dysregulation.

PubMed

Evans, Gary W; Kim, Pilyoung

2007-11-01

A massive literature documents the inverse association between poverty or low socioeconomic status and health, but little is known about the mechanisms underlying this robust relation. We examined longitudinal relations between duration of poverty exposure since birth, cumulative risk exposure, and physiological stress in two hundred seven 13-year-olds. Chronic stress was assessed by basal blood pressure and overnight cortisol levels; stress regulation was assessed by cardiovascular reactivity to a standard acute stressor and recovery after exposure to this stressor. Cumulative risk exposure was measured by multiple physical (e.g., substandard housing) and social (e.g., family turmoil) risk factors. The greater the number of years spent living in poverty, the more elevated was overnight cortisol and the more dysregulated was the cardiovascular response (i.e., muted reactivity). Cardiovascular recovery was not affected by duration of poverty exposure. Unlike the duration of poverty exposure, concurrent poverty (i.e., during adolescence) did not affect these physiological stress outcomes. The effects of childhood poverty on stress dysregulation are largely explained by cumulative risk exposure accompanying childhood poverty.

A Conceptual Framework for the Assessment of Cumulative Exposure to Air Pollution at a Fine Spatial Scale

PubMed Central

Wahida, Kihal-Talantikite; Padilla, Cindy M.; Denis, Zmirou-Navier; Olivier, Blanchard; Géraldine, Le Nir; Philippe, Quenel; Séverine, Deguen

2016-01-01

Many epidemiological studies examining long-term health effects of exposure to air pollutants have characterized exposure by the outdoor air concentrations at sites that may be distant to subjects’ residences at different points in time. The temporal and spatial mobility of subjects and the spatial scale of exposure assessment could thus lead to misclassification in the cumulative exposure estimation. This paper attempts to fill the gap regarding cumulative exposure assessment to air pollution at a fine spatial scale in epidemiological studies investigating long-term health effects. We propose a conceptual framework showing how major difficulties in cumulative long-term exposure assessment could be surmounted. We then illustrate this conceptual model on the case of exposure to NO2 following two steps: (i) retrospective reconstitution of NO2 concentrations at a fine spatial scale; and (ii) a novel approach to assigning the time-relevant exposure estimates at the census block level, using all available data on residential mobility throughout a 10- to 20-year period prior to that for which the health events are to be detected. Our conceptual framework is both flexible and convenient for the needs of different epidemiological study designs. PMID:26999170

A Conceptual Framework for the Assessment of Cumulative Exposure to Air Pollution at a Fine Spatial Scale.

PubMed

Wahida, Kihal-Talantikite; Padilla, Cindy M; Denis, Zmirou-Navier; Olivier, Blanchard; Géraldine, Le Nir; Philippe, Quenel; Séverine, Deguen

2016-03-15

Many epidemiological studies examining long-term health effects of exposure to air pollutants have characterized exposure by the outdoor air concentrations at sites that may be distant to subjects' residences at different points in time. The temporal and spatial mobility of subjects and the spatial scale of exposure assessment could thus lead to misclassification in the cumulative exposure estimation. This paper attempts to fill the gap regarding cumulative exposure assessment to air pollution at a fine spatial scale in epidemiological studies investigating long-term health effects. We propose a conceptual framework showing how major difficulties in cumulative long-term exposure assessment could be surmounted. We then illustrate this conceptual model on the case of exposure to NO₂ following two steps: (i) retrospective reconstitution of NO₂ concentrations at a fine spatial scale; and (ii) a novel approach to assigning the time-relevant exposure estimates at the census block level, using all available data on residential mobility throughout a 10- to 20-year period prior to that for which the health events are to be detected. Our conceptual framework is both flexible and convenient for the needs of different epidemiological study designs.

Anemia risk in relation to lead exposure in lead-related manufacturing.

PubMed

Hsieh, Nan-Hung; Chung, Shun-Hui; Chen, Szu-Chieh; Chen, Wei-Yu; Cheng, Yi-Hsien; Lin, Yi-Jun; You, Su-Han; Liao, Chung-Min

2017-05-05

Lead-exposed workers may suffer adverse health effects under the currently regulated blood lead (BPb) levels. However, a probabilistic assessment about lead exposure-associated anemia risk is lacking. The goal of this study was to examine the association between lead exposure and anemia risk among factory workers in Taiwan. We first collated BPb and indicators of hematopoietic function data via health examination records that included 533 male and 218 female lead-exposed workers between 2012 and 2014. We used benchmark dose (BMD) modeling to estimate the critical effect doses for detection of abnormal indicators. A risk-based probabilistic model was used to characterize the potential hazard of lead poisoning for job-specific workers by hazard index (HI). We applied Bayesian decision analysis to determine whether BMD could be implicated as a suitable BPb standard. Our results indicated that HI for total lead-exposed workers was 0.78 (95% confidence interval: 0.50-1.26) with risk occurrence probability of 11.1%. The abnormal risk of anemia indicators for male and female workers could be reduced, respectively, by 67-77% and 86-95% by adopting the suggested BPb standards of 25 and 15 μg/dL. We conclude that cumulative exposure to lead in the workplace was significantly associated with anemia risk. This study suggests that current BPb standard needs to be better understood for the application of lead-exposed population protection in different scenarios to provide a novel standard for health management. Low-level lead exposure risk is an occupational and public health problem that should be paid more attention.

Latino Mothers' Cumulative Food Insecurity Exposure and Child Body Composition.

PubMed

Hernandez, Daphne C

2016-01-01

To document whether an intergenerational transmission of food insecurity is occurring by assessing low-income foreign-born Latino mothers' experiences with food insecurity as none, once (either childhood or adulthood) or twice (during both childhood and adulthood). Also the association between maternal cumulative food insecurity and children's body composition was examined. Maternal self-reported surveys on retrospective measures of food insecurity during childhood, current measures of food insecurity, and demographics were collected from Houston-area community centers (N = 96). Children's body mass index (BMI) and waist circumference (WC) were directly assessed. Covariate-adjusted logistic regression models analyzed the association between cumulative food insecurity experiences and children's body composition. Fifty-eight percent of mothers experienced food insecurity both as a child and as an adult and 31% of the mothers experienced food insecurity either as a child or adult. Maternal cumulative exposure to food insecurity was unrelated to BMI but was negatively related to elevated WC. Although an intergenerational transmission of food insecurity does exist, maternal cumulative exposure to food insecurity does not impact children's body composition negatively in the short term. Studying the long-term effects of cumulative food insecurity exposure can provide information for the development and timing of obesity interventions.

Evaluation of cumulative PCB exposure estimated by a job exposure matrix versus PCB serum concentrations

PubMed Central

Ruder, Avima M.; Succop, Paul; Waters, Martha A.

2015-01-01

Although polychlorinated biphenyls (PCBs) have been banned in many countries for more than three decades, exposures to PCBs continue to be of concern due to their long half-lives and carcinogenic effects. In National Institute for Occupational Safety and Health studies, we are using semiquantitative plant-specific job exposure matrices (JEMs) to estimate historical PCB exposures for workers (n=24,865) exposed to PCBs from 1938 to 1978 at three capacitor manufacturing plants. A subcohort of these workers (n=410) employed in two of these plants had serum PCB concentrations measured at up to four times between 1976 and 1989. Our objectives were to evaluate the strength of association between an individual worker’s measured serum PCB levels and the same worker’s cumulative exposure estimated through 1977 with the (1) JEM and (2) duration of employment, and to calculate the explained variance the JEM provides for serum PCB levels using (3) simple linear regression. Consistent strong and statistically significant associations were observed between the cumulative exposures estimated with the JEM and serum PCB concentrations for all years. The strength of association between duration of employment and serum PCBs was good for highly chlorinated (Aroclor 1254/HPCB) but not less chlorinated (Aroclor 1242/LPCB) PCBs. In the simple regression models, cumulative occupational exposure estimated using the JEMs explained 14–24 % of the variance of the Aroclor 1242/LPCB and 22–39 % for Aroclor 1254/HPCB serum concentrations. We regard the cumulative exposure estimated with the JEM as a better estimate of PCB body burdens than serum concentrations quantified as Aroclor 1242/LPCB and Aroclor 1254/HPCB. PMID:23475397

Stakeholder attitudes towards cumulative and aggregate exposure assessment of pesticides.

PubMed

Verbeke, Wim; Van Loo, Ellen J; Vanhonacker, Filiep; Delcour, Ilse; Spanoghe, Pieter; van Klaveren, Jacob D

2015-05-01

This study evaluates the attitudes and perspectives of different stakeholder groups (agricultural producers, pesticide manufacturers, trading companies, retailers, regulators, food safety authorities, scientists and NGOs) towards the concepts of cumulative and aggregate exposure assessment of pesticides by means of qualitative in-depth interviews (n = 15) and a quantitative stakeholder survey (n = 65). The stakeholders involved generally agreed that the use of chemical pesticides is needed, primarily for meeting the need of feeding the growing world population, while clearly acknowledging the problematic nature of human exposure to pesticide residues. Current monitoring was generally perceived to be adequate, but the timeliness and consistency of monitoring practices across countries were questioned. The concept of cumulative exposure assessment was better understood by stakeholders than the concept of aggregate exposure assessment. Identified pitfalls were data availability, data limitations, sources and ways of dealing with uncertainties, as well as information and training needs. Regulators and food safety authorities were perceived as the stakeholder groups for whom cumulative and aggregate pesticide exposure assessment methods and tools would be most useful and acceptable. Insights obtained from this exploratory study have been integrated in the development of targeted and stakeholder-tailored dissemination and training programmes that were implemented within the EU-FP7 project ACROPOLIS. Copyright © 2014 Elsevier Ltd. All rights reserved.

The EPA's human exposure research program for assessing cumulative risk in communities.

PubMed

Zartarian, Valerie G; Schultz, Bradley D

2010-06-01

Communities are faced with challenges in identifying and prioritizing environmental issues, taking actions to reduce their exposures, and determining their effectiveness for reducing human health risks. Additional challenges include determining what scientific tools are available and most relevant, and understanding how to use those tools; given these barriers, community groups tend to rely more on risk perception than science. The U.S. Environmental Protection Agency's Office of Research and Development, National Exposure Research Laboratory (NERL) and collaborators are developing and applying tools (models, data, methods) for enhancing cumulative risk assessments. The NERL's "Cumulative Communities Research Program" focuses on key science questions: (1) How to systematically identify and prioritize key chemical stressors within a given community?; (2) How to develop estimates of exposure to multiple stressors for individuals in epidemiologic studies?; and (3) What tools can be used to assess community-level distributions of exposures for the development and evaluation of the effectiveness of risk reduction strategies? This paper provides community partners and scientific researchers with an understanding of the NERL research program and other efforts to address cumulative community risks; and key research needs and opportunities. Some initial findings include the following: (1) Many useful tools exist for components of risk assessment, but need to be developed collaboratively with end users and made more comprehensive and user-friendly for practical application; (2) Tools for quantifying cumulative risks and impact of community risk reduction activities are also needed; (3) More data are needed to assess community- and individual-level exposures, and to link exposure-related information with health effects; and (4) Additional research is needed to incorporate risk-modifying factors ("non-chemical stressors") into cumulative risk assessments. The products of this

Cumulative radiation exposure and cancer risk estimation in children with heart disease.

PubMed

Johnson, Jason N; Hornik, Christoph P; Li, Jennifer S; Benjamin, Daniel K; Yoshizumi, Terry T; Reiman, Robert E; Frush, Donald P; Hill, Kevin D

2014-07-08

Children with heart disease are frequently exposed to imaging examinations that use ionizing radiation. Although radiation exposure is potentially carcinogenic, there are limited data on cumulative exposure and the associated cancer risk. We evaluated the cumulative effective dose of radiation from all radiation examinations to estimate the lifetime attributable risk of cancer in children with heart disease. Children ≤6 years of age who had previously undergone 1 of 7 primary surgical procedures for heart disease at a single institution between 2005 and 2010 were eligible for the study. Exposure to radiation-producing examinations was tabulated, and cumulative effective dose was calculated in millisieverts. These data were used to estimate lifetime attributable risk of cancer above baseline using the approach of the Committee on Biological Effects of Ionizing Radiation VII. The cohort included 337 children exposed to 13 932 radiation examinations. Conventional radiographs represented 92% of examinations, whereas cardiac catheterization and computed tomography accounted for 81% of cumulative exposure. Overall median cumulative effective dose was 2.7 mSv (range, 0.1-76.9 mSv), and the associated lifetime attributable risk of cancer was 0.07% (range, 0.001%-6.5%). Median lifetime attributable risk of cancer ranged widely depending on surgical complexity (0.006%-1.6% for the 7 surgical cohorts) and was twice as high in females per unit exposure (0.04% versus 0.02% per 1-mSv effective dose for females versus males, respectively; P<0.001). Overall radiation exposures in children with heart disease are relatively low; however, select cohorts receive significant exposure. Cancer risk estimation highlights the need to limit radiation dose, particularly for high-exposure modalities. © 2014 American Heart Association, Inc.

Occupational exposure to lead and lung cancer: results from two case-control studies in Montreal, Canada.

PubMed

Wynant, Willy; Siemiatycki, Jack; Parent, Marie-Élise; Rousseau, Marie-Claude

2013-03-01

We investigated the association between workplace lead exposure and lung cancer risk, separately for organic lead and for inorganic lead, from either engine emissions or from other sources. Two population-based case-control studies were carried out in Montreal (1979-1986 and 1996-2002) to investigate occupational factors in relation to lung cancer among 1593 men with histologically confirmed incident lung cancer, and 1426 controls from the general population. Interviews elicited information on sociodemographic characteristics, lifetime smoking and occupational history. Chemists translated each job into potential chemical exposures. Cumulative indices of exposure were derived and classified into non-substantial and substantial exposure. ORs adjusted for several potential confounders including smoking, and 95% CIs were estimated by logistic regression. Lifetime prevalences of exposure in Study I were 3% for organic lead, 40% for inorganic lead from engine emissions and 17% for inorganic lead from other sources; corresponding prevalences in Study II were 4%, 19% and 16%, respectively. No associations were observed when comparing ever to never exposed subjects in pooled analyses (organic lead, OR=1.39, 95% CI 0.77 to 2.52; inorganic lead from engine emissions: OR=0.89, 95% CI 0.72 to 1.09; inorganic lead from other sources: OR=0.99, 95% CI 0.76 to 1.29). Nor were these exposures associated with lung cancer in subjects with substantial cumulative exposure. In this large study, using a blinded expert-based assessment of lifetime occupational exposure and adjustment for several potential confounders, we observed no increased risk of lung cancer with exposure to lead compounds.

Respiratory exposures associated with silicon carbide production: estimation of cumulative exposures for an epidemiological study.

PubMed Central

Smith, T J; Hammond, S K; Laidlaw, F; Fine, S

1984-01-01

Silicon carbide is produced by heating a mixture of petroleum coke and silica sand to approximately 2000 degrees C in an electric furnace for 36 hours. During heating, large amounts of carbon monoxide are released, sulphur dioxide is produced from residual sulphur in the coke, and hydrocarbon fume is produced by pyrolysis of the coke. Loading and unloading furnaces causes exposures to respirable dust containing crystalline silica, silicon carbide, and hydrocarbons. In the autumn of 1980 extensive measurements were made of personal exposures to air contaminants. Eight hour time weighted exposures to sulphur dioxide ranged from less than 0.1 ppm to 1.5 ppm and respirable participate exposures ranged from 0.01 mg/m3 to 9.0 mg/m3. Geometric mean particulate exposures for jobs ranged from 0.1 mg/m3 to 1.46 mg/m3. The particulate contained varying amounts of alpha-quartz, ranging from less than 1% to 17%, and most quartz exposures were substantially below the threshold limit value of 100 micrograms/m3. Only traces of cristobalite (less than 1%) were found in the particulate. Median exposures to air contaminants in each job were estimated. Since the operations at the plant had been stable over the past 30 years, it was possible to estimate long term exposures of workers to sulphur dioxide, respirable particulate, quartz, total inorganic material, and extractable organic material. Cumulative exposure (average concentration times exposure duration) for each of the air contaminants was estimated for each worker using his job history. There was sufficient independent variability in the sulphur dioxide and respirable particulate cumulative exposures to make an assessment of their independent effects feasible. The theoretical basis for using the cumulative exposure index and its shortcomings for epidemiological applications were presented. PMID:6691927

CUMULATIVE PM2.5 EXPOSURE AND TELOMERE LENGTH IN WORKERS EXPOSED TO WELDING FUMES

PubMed Central

Wong, Jason Y. Y.; De Vivo, Immaculata; Lin, Xihong; Christiani, David C.

2014-01-01

Telomeres are genomic structures that reflect both mitotic history and biochemical trauma to the genome. Metals inherent in fine particulate matter (PM2.5) were shown to be genotoxic via oxidative damage. However, few studies investigated the induction time of cumulative PM2.5 exposure on telomere length in a longitudinal setting. Therefore, the purpose of this study was to assess the association between occupational PM2.5 exposure in various time windows and telomere length. The study population consisted of 48 boilermakers and the follow-up period was 8 yr. The main exposures were cumulative occupational PM2.5 in the month, year, and career prior to each blood draw, assessed via work history questionnaires and area air measures. Repeated telomere length measurements from leukocytes were assessed via real-time quantitative polymerase chain reaction (qPCR). Analysis was performed using linear mixed models controlling for confounders and white blood cell differentials. Cumulative PM2.5 exposure was treated continuously and categorized into quartiles, in separate analyses. At any follow-up time, for each milligram per cubic meter per hour increase in cumulative PM2.5 exposure in the prior month, there was a statistically significant decrease in relative telomere length of −0.04 units. When categorizing the exposure into quartiles, there was a significant negative association between telomere length and highest quartile of cumulative PM2.5 exposure in the prior month (−0.16). These findings suggest that genomic trauma to leukocyte telomeres was more consistent with recent occupational PM2.5 exposure, as opposed to cumulative exposure extending into the distant past. PMID:24627998

Cumulative estrogen exposure and prospective memory in older women.

PubMed

Hesson, Jacqueline

2012-10-01

This study looked at cumulative lifetime estrogen exposure, as estimated with a mathematical index (Index of Cumulative Estrogen Exposure (ICEE)) that included variables (length of time on estrogen therapy, age at menarche and menopause, postmenopausal body mass index, time since menopause, nulliparity and duration of breastfeeding) known to influence estrogen levels across the life span, and performance on prospective and retrospective memory measures in a group of 50 postmenopausal women (mean age=69.3years) who, if they were current or former users of estrogen therapy, had started therapy within 5years of menopause. The ICEE was found to be a significant predictor of performance on the Prospective Memory task (F(1)=4.21, p=.046, η(p)(2)=.084). No significant relationship was noted between the ICEE and performance on measures of retrospective memory. The results suggest that the level of cumulative lifetime exposure to estrogen a woman has influences her prospective memory performance later in life and that the influence of reproductive and biological markers of endogenous estrogen exposure are relevant factors to consider when studying the effect of estrogen therapy on cognitive functioning in postmenopausal women. In addition, the finding that performance on a measure of prospective memory, but not performance on measures of retrospective memory, was associated with the ICEE adds further support to the theory that the frontal cortex may be especially sensitive to estrogen. Copyright © 2012 Elsevier Inc. All rights reserved.

The cumulative MeHg and PCBs exposure and risk of tribal ...

EPA Pesticide Factsheets

Studies have shown that the U.S. population continues to be exposed to methyl mercury (MeHg) and polychlorinated biphenyls (PCBs) due to the long half-life of those environmental contaminants. Fish intake of Tribal populations is much higher than the U.S. general population due to dietary habits and unique cultural practices. Large fish tissue concentration data sets from the Environmental Protections Agency’s (EPA’s) Office of Water, USGS’s EMMMA program, and other data sources, were integrated, analyzed, and combined with recent tribal fish intake data for exposure analyses using the dietary module within EPA’s SHEDS-Multimedia model. SHEDS-Multimedia is a physically-based, probabilistic model, which can simulate cumulative (multiple chemicals) or aggregate (single chemical) exposures over time for a population via various pathways of exposure for a variety of multimedia, multipathway environmental chemicals. Our results show that MeHg and total PCBs exposure of tribal populations from fish are about 3 to 10 and 5 to 15 times higher than the US general population, respectively, and that the estimated exposures pose potential health risks. The cumulative exposures of MeHg and total PCBs will be assessed to generate the joint exposure profiles for Tribal and US general populations. Model sensitivity analyses will identify the important contributions of the cumulative exposures of MeHg and total PCBs such as fish types, locations, and size, and key expos

Cumulative asbestos exposure for US automobile mechanics involved in brake repair (circa 1950s-2000).

PubMed

Finley, Brent L; Richter, Richard O; Mowat, Fionna S; Mlynarek, Steve; Paustenbach, Dennis J; Warmerdam, John M; Sheehan, Patrick J

2007-11-01

We analyzed cumulative lifetime exposure to chrysotile asbestos experienced by brake mechanics in the US during the period 1950-2000. Using Monte Carlo methods, cumulative exposures were calculated using the distribution of 8-h time-weighted average exposure concentrations for brake mechanics and the distribution of job tenure data for automobile mechanics. The median estimated cumulative exposures for these mechanics, as predicted by three probabilistic models, ranged from 0.16 to 0.41 fibers per cubic centimeter (f/cm(3)) year for facilities with no dust-control procedures (1970s), and from 0.010 to 0.012 f/cm(3) year for those employing engineering controls (1980s). Upper-bound (95%) estimates for the 1970s and 1980s were 1.96 to 2.79 and 0.07-0.10 f/cm(3) year, respectively. These estimates for US brake mechanics are consistent with, but generally slightly lower than, those reported for European mechanics. The values are all substantially lower than the cumulative exposure of 4.5 f/cm(3) year associated with occupational exposure to 0.1 f/cm(3) of asbestos for 45 years that is currently permitted under the current occupational exposure limits in the US. Cumulative exposures were usually about 100- to 1,000-fold less than those of other occupational groups with asbestos exposure for similar time periods. The cumulative lifetime exposure estimates presented here, combined with the negative epidemiology data for brake mechanics, could be used to refine the risk assessments for chrysotile-exposed populations.

Cumulative effects from repeated exposures to ultraviolet radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaidbey, K.H.; Kligman, A.M.

Repeated exposures to subliminal doses of UVR, given at 24-hr intervals, resulted in a lowering of the erythema threshold dose. At erythemogenically equivalent doses, UV-A was the most effective and UV-C the least. A similar and more pronounced effect was observed following repeated exposures to subthreshold doses of UV-A and topically applied 8-methoxypsoralen. These findings provide quantitative evidence for the cumulative nature of acute UVR damage in human skin.

Cumulant generating function formula of heat transfer in ballistic systems with lead-lead coupling

NASA Astrophysics Data System (ADS)

Li, Huanan; Agarwalla, Bijay Kumar; Wang, Jian-Sheng

2012-10-01

Based on a two-time observation protocol, we consider heat transfer in a given time interval tM in a lead-junction-lead system taking coupling between the leads into account. In view of the two-time observation, consistency conditions are carefully verified in our specific family of quantum histories. Furthermore, its implication is briefly explored. Then using the nonequilibrium Green's function method, we obtain an exact formula for the cumulant generating function for heat transfer between the two leads, valid in both transient and steady-state regimes. Also, a compact formula for the cumulant generating function in the long-time limit is derived, for which the Gallavotti-Cohen fluctuation symmetry is explicitly verified. In addition, we briefly discuss Di Ventra's repartitioning trick regarding whether the repartitioning procedure of the total Hamiltonian affects the nonequilibrium steady-state current fluctuation. All kinds of properties of nonequilibrium current fluctuations, such as the fluctuation theorem in different time regimes, could be readily given according to these exact formulas.

Cumulative exposure to dust causes accelerated decline in lung function in tunnel workers

PubMed Central

Ulvestad, B; Bakke, B; Eduard, W; Kongerud, J; Lund, M

2001-01-01

OBJECTIVES—To examine whether underground construction workers exposed to tunnelling pollutants over a follow up period of 8 years have an increased risk of decline in lung function and respiratory symptoms compared with reference subjects working outside the tunnel atmosphere, and relate the findings to job groups and cumulative exposure to dust and gases.
METHODS—96 Tunnel workers and a reference group of 249 other heavy construction workers were examined in 1991 and re-examined in 1999. Exposure measurements were carried out to estimate personal cumulative exposure to total dust, respirable dust, α-quartz, oil mist, and nitrogen dioxide. The subjects answered a questionnaire on respiratory symptoms and smoking habits, performed spirometry, and had chest radiographs taken. Radiological signs of silicosis were evaluated (International Labour Organisation (ILO) classification). Atopy was determined by a multiple radioallergosorbent test (RAST).
RESULTS—The mean exposure to respirable dust and α-quartz in tunnel workers varied from 1.2-3.6 mg/m3 (respirable dust) and 0.019-0.044 mg/m3 (α-quartz) depending on job task performed. Decrease in forced expiratory volume in 1 second (FEV1) was associated with cumulative exposure to respirable dust (p<0.001) and α-quartz (p=0.02). The multiple regression model predicted that in a worker 40 years of age, the annual decrease in FEV1 would be 25 ml in a non-exposed non-smoker, 35 ml in a non-exposed smoker, and 50-63 ml in a non-smoking tunnel worker (depending on job). Compared with the reference group the odds ratio for the occurrence of new respiratory symptoms during the follow up period was increased in the tunnel workers and associated with cumulative exposure to respirable dust.
CONCLUSIONS—Cumulative exposures to respirable dust and α-quartz are the most important risk factors for airflow limitation in underground heavy construction workers, and cumulative exposure to respirable dust is the

Modeling cumulative dose and exposure duration provided insights regarding the associations between benzodiazepines and injuries.

PubMed

Abrahamowicz, Michal; Bartlett, Gillian; Tamblyn, Robyn; du Berger, Roxane

2006-04-01

Accurate assessment of medication impact requires modeling cumulative effects of exposure duration and dose; however, postmarketing studies usually represent medication exposure by baseline or current use only. We propose new methods for modeling various aspects of medication use history and employment of them to assess the adverse effects of selected benzodiazepines. Time-dependent measures of cumulative dose or duration of use, with weighting of past exposures by recency, were proposed. These measures were then included in alternative versions of the multivariable Cox model to analyze the risk of fall related injuries among the elderly new users of three benzodiazepines (nitrazepam, temazepam, and flurazepam) in Quebec. Akaike's information criterion (AIC) was used to select the most predictive model for a given benzodiazepine. The best-fitting model included a combination of cumulative duration and current dose for temazepam, and cumulative dose for flurazepam and nitrazepam, with different weighting functions. The window of clinically relevant exposure was shorter for flurazepam than for the two other products. Careful modeling of the medication exposure history may enhance our understanding of the mechanisms underlying their adverse effects.

Lead Exposure and Tremor among Older Men: The VA Normative Aging Study

PubMed Central

Power, Melinda C.; Sparrow, David; Spiro, Avron; Hu, Howard; Louis, Elan D.; Weisskopf, Marc G.

2015-01-01

Background: Tremor is one of the most common neurological signs, yet its etiology is poorly understood. Case–control studies suggest an association between blood lead and essential tremor, and that this association is modified by polymorphisms in the δ-aminolevulinic acid dehydrogenase (ALAD) gene. Objective: We aimed to examine the relationship between lead and tremor, including modification by ALAD, in a prospective cohort study, using both blood lead and bone lead—a biomarker of cumulative lead exposure. Methods: We measured tibia (n = 670) and patella (n = 672) bone lead and blood lead (n = 807) among older men (age range, 50–98 years) in the VA Normative Aging Study cohort. A tremor score was created based on an approach using hand-drawing samples. ALAD genotype was dichotomized as ALAD-2 carriers or not. We used linear regression adjusted for age, education, smoking, and alcohol intake to estimate the associations between lead biomarkers and tremor score. Results: In unadjusted analyses, there was a marginal association between quintiles of all lead biomarkers and tremor scores (p-values < 0.13), which did not persist in adjusted models. Age was the strongest predictor of tremor. Among those younger than the median age (68.9 years), tremor increased significantly with blood lead (p = 0.03), but this pattern was not apparent for bone lead. We did not see modification by ALAD or an association between bone lead and change in tremor score over time. Conclusion: Our results do not strongly support an association between lead exposure and tremor, and suggest no association with cumulative lead biomarkers, although there is some suggestion that blood lead may be associated with tremor among the younger men in our cohort. Citation: Ji JS, Power MC, Sparrow D, Spiro A III, Hu H, Louis ED, Weisskopf MG. 2015. Lead exposure and tremor among older men: the VA Normative Aging Study. Environ Health Perspect 123:445–450; http://dx.doi.org/10.1289/ehp.1408535

Cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome: a nationwide Danish cohort study.

PubMed

Dalbøge, Annett; Frost, Poul; Andersen, Johan Hviid; Svendsen, Susanne Wulff

2014-11-01

The primary aim was to examine exposure-response relationships between cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome (SIS), and to compare sex-specific exposure-response relationships. The secondary aim was to examine the time window of relevant exposures. We conducted a nationwide register study of all persons born in Denmark (1933-1977), who had at least 5 years of full-time employment. In the follow-up period (2003-2008), we identified first-time events of surgery for SIS. Cumulative exposure estimates for a 10-year exposure time window with a 1-year lag time were obtained by linking occupational codes with a job exposure matrix. The exposure estimates were expressed as, for example, arm-elevation-years in accordance with the pack-year concept of tobacco consumption. We used a multivariable logistic regression technique equivalent to discrete survival analysis. The adjusted OR (ORadj) increased to a maximum of 2.1 for arm-elevation-years, repetition-years and force-years, and to 1.5 for hand-arm-vibration-years. Sex-specific exposure-response relationships were similar for men and women, when assessed using a relative risk scale. The ORadj increased gradually with the number of years contributing to the cumulative exposure estimates. The excess fraction was 24%. Cumulative occupational shoulder exposures carried an increase in risk of surgery for SIS with similar exposure-response curves for men and women. The risk of surgery for SIS increased gradually, when the period of exposure assessment was extended. In the general working population, a substantial fraction of all first-time operations for SIS could be related to occupational exposures. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Toddler temperament and prenatal exposure to lead and maternal depression.

PubMed

Stroustrup, Annemarie; Hsu, Hsiao-Hsien; Svensson, Katherine; Schnaas, Lourdes; Cantoral, Alejandra; Solano González, Maritsa; Torres-Calapiz, Mariana; Amarasiriwardena, Chitra; Bellinger, David C; Coull, Brent A; Téllez-Rojo, Martha M; Wright, Robert O; Wright, Rosalind J

2016-06-16

Temperament is a psychological construct that reflects both personality and an infant's reaction to social stimuli. It can be assessed early in life and is stable over time Temperament predicts many later life behaviors and illnesses, including impulsivity, emotional regulation and obesity. Early life exposure to neurotoxicants often results in developmental deficits in attention, social function, and IQ, but environmental predictors of infant temperament are largely unknown. We propose that prenatal exposure to both chemical and non-chemical environmental toxicants impacts the development of temperament, which can itself be used as a marker of risk for maladaptive neurobehavior in later life. In this study, we assessed associations among prenatal and early life exposure to lead, mercury, poverty, maternal depression and toddler temperament. A prospective cohort of women living in the Mexico City area were followed longitudinally beginning in the second trimester of pregnancy. Prenatal exposure to lead (blood, bone), mercury, and maternal depression were assessed repeatedly and the Toddler Temperament Scale (TTS) was completed when the child was 24 months old. The association between each measure of prenatal exposure and performance on individual TTS subscales was evaluated by multivariable linear regression. Latent profile analysis was used to classify subjects by TTS performance. Multinomial regression models were used to estimate the prospective association between prenatal exposures and TTS performance. 500 mother-child pairs completed the TTS and had complete data on exposures and covariates. Three latent profiles were identified and categorized as predominantly difficult, intermediate, or easy temperament. Prenatal exposure to maternal depression predicted increasing probability of difficult toddler temperament. Maternal bone lead, a marker of cumulative exposure, also predicted difficult temperament. Prenatal lead exposure modified this association

Cumulant generating function formula of heat transfer in ballistic systems with lead-lead coupling and general nonlinear systems

NASA Astrophysics Data System (ADS)

Li, Huanan

2013-03-01

Based on a two-time observation protocol, we consider heat transfer in a given time interval tM in a lead-junction-lead system taking coupling between the leads into account. In view of the two-time observation, consistency conditions are carefully verified in our specific family of quantum histories. Furthermore, its implication is briefly explored. Then using the nonequilibrium Green's function method, we obtain an exact formula for the cumulant generating function for heat transfer between the two leads, valid in both transient and steady-state regimes. Also, a compact formula for the cumulant generating function in the long-time limit is derived, for which the Gallavotti-Cohen fluctuation symmetry is explicitly verified. In addition, we briefly discuss Di Ventra's repartitioning trick regarding whether the repartitioning procedure of the total Hamiltonian affects the nonequilibrium steady-state current fluctuation. All kinds of properties of nonequilibrium current fluctuations, such as the fluctuation theorem in different time regimes, could be readily given according to these exact formulas. Finally a practical formalism dealing with cumulants of heat transfer across general nonlinear quantum systems is established based on field theoretical/algebraic method.

Applications of measures of cumulative exposure to assessing air pollution health effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbey, D.E.; Euler, G.L.; Magie, A.R.

A method for assessing the health effects of long-term cumulative exposures to air pollutants or other environmental exposures is proposed and illustrated using self-reported symptoms of chronic obstructive pulmonary disease (COPD) for a population of 7,343 non-smokers. Using zip code by month, residence histories, and interpolated exposure estimates from the network of California air monitoring stations, two alternative exposure indices were calculated to estimate cumulative exposure over an 11-yr period above different threshold levels for each of four pollutants. The indices were used with multiple logistic regression models to form dose-response curves for relative risks adjusting for covariates. Statistically significantmore » effects were noted for total suspended particulates, total oxidants, sulfur dioxide, and passive smoking. A description is also given of how the indices are currently being used in a 10-yr follow-up of the study population. This follow-up study is utilizing data collected by the National Cancer Institute-funded Adventist Health Study and has mortality, cancer incidence, heart disease incidence, and change in self-reported COPD symptoms as outcomes.« less

Aggregate Exposure and Cumulative Risk Assessment—Integrating Occupational and Non-occupational Risk Factors

PubMed Central

Lentz, T. J.; Dotson, G. S.; Williams, P. R.D.; Maier, A.; Gadagbui, B.; Pandalai, S. P.; Lamba, A.; Hearl, F.; Mumtaz, M.

2015-01-01

Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational. PMID:26583907

Aggregate Exposure and Cumulative Risk Assessment--Integrating Occupational and Non-occupational Risk Factors.

PubMed

Lentz, T J; Dotson, G S; Williams, P R D; Maier, A; Gadagbui, B; Pandalai, S P; Lamba, A; Hearl, F; Mumtaz, M

2015-01-01

Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational.

Fetal Substance Exposure and Cumulative Environmental Risk in an African American Cohort

ERIC Educational Resources Information Center

Yumoto, Chie; Jacobson, Sandra W.; Jacobson, Joseph L.

2008-01-01

Two models of vulnerability to socioenvironmental risk were examined in 337 African American children (M = 7.8 years) recruited to overrepresent prenatal alcohol or cocaine exposure: The cumulative risk model predicted synergistic effects from exposure to multiple risk factors, and the fetal patterning of disease model predicted that prenatal…

HESI EXPOSURE FACTORS DATABASE FOR AGGREGATE AND CUMULATIVE RISK ASSESSMENT

EPA Science Inventory

In recent years, the risk analysis community has broadened its use of complex aggregate and cumulative residential exposure models (e.g., to meet the requirements of the 1996 Food Quality Protection Act). The value of these models is their ability to incorporate a range of inp...

Methodologies for Estimating Cumulative Human Exposures to Current-Use Pyrethroid Pesticides

EPA Science Inventory

We estimated cumulative residential pesticide exposures for a group of nine young children (4–6 years) using three different methodologies developed by the US Environmental Protection Agency and compared the results with estimates derived from measured urinary metabolite concentr...

Cumulative violence exposure, emotional nonacceptance, and mental health symptoms in a community sample of women.

PubMed

Sundermann, Jane M; Chu, Ann T; DePrince, Anne P

2013-01-01

Women exposed to more types of violence (e.g., emotional, physical, or sexual violence)--referred to here as cumulative violence exposure--are at risk for more severe mental health symptoms compared to women who are exposed to a single type of violence or no violence. Women exposed to violence may also experience greater emotional nonacceptance compared to women with no exposure to violence. Emotional nonacceptance refers to an unwillingness to experience emotional states, including cognitive and behavioral attempts to avoid experiences of emotion. Given the links between cumulative violence exposure, emotional nonacceptance, and mental health symptoms among female victims of violence, the current study tested victims' emotional nonacceptance as a partial mediator between cumulative violence exposure and the severity of 3 types of symptoms central to complex trauma responses: depression, dissociation, and posttraumatic stress disorder (PTSD) symptoms. A non-treatment-seeking community sample of women (N = 89; M age = 30.70 years) completed self-report questionnaires and interviews. Bootstrap procedures were then used to test 3 mediation models for the separate predictions of depression, dissociation, and PTSD symptoms. Results supported our hypotheses that emotional nonacceptance would mediate the relationship between women's cumulative violence exposure and severity for all symptom types. The current findings highlight the role that emotional nonacceptance may play in the development of mental health symptoms for chronically victimized women and point to the need for longitudinal research in such populations.

Is Cumulative Exposure to Suicide Attempts and Deaths A Risk Factor for Suicidal Behavior among Firefighters? A Preliminary Study

PubMed Central

Kimbrel, Nathan A.; Pennington, Michelle L.; Cammarata, Claire M.; Leto, Frank; Ostiguy, William J.; Gulliver, Suzy B.

2016-01-01

The present study examined the association between cumulative exposure to suicide attempts and deaths and suicidal behavior in a sample of 61 professional firefighters. On average, firefighters reported 13.1 (SD=16.6) exposures over the course of their lifetime. Cumulative exposure to suicide attempts and deaths was positively correlated with suicidal behavior (r = 0.38, p = 0.004). Moreover, firefighters with 12+ exposures were more likely to screen positive for risk of suicidal behavior (OR = 7.885, p = 0.02). Additional research on the potential impact of cumulative exposure to suicide attempts and deaths on firefighters’ health and safety is needed. PMID:27371810

Occupational exposures to leaded and unleaded gasoline engine emissions and lung cancer risk.

PubMed

Xu, Mengting; Siemiatycki, Jack; Lavoué, Jérôme; Pasquet, Romain; Pintos, Javier; Rousseau, Marie-Claude; Richardson, Lesley; Ho, Vikki

2018-04-01

To determine whether occupational exposure to gasoline engine emissions (GEE) increased the risk of lung cancer and more specifically whether leaded or unleaded GEE increased the risk. Two population-based case-control studies were conducted in Montreal, Canada. The first was conducted in the early 1980s and included many types of cancer including lung cancer. The second was conducted in the late 1990s and focused on lung cancer. Population controls were used in both studies. Altogether, there were 1595 cases and 1432 population controls. A comprehensive expert-based exposure assessment procedure was implemented and exposure was assessed for 294 agents, including unleaded GEE, leaded GEE and diesel engine emissions (DEE). Logistic regression analyses were conducted to estimate ORs between various metrics of GEE exposure and lung cancer, adjusting for smoking, DEE and other potential confounders. About half of all controls were occupationally exposed to GEE. Irrespective of the metrics of exposure (any exposure, duration of exposure and cumulative exposure) and the type of lung cancer, and the covariates included in models, none of the point estimates of the ORs between occupational exposure to leaded or unleaded GEE and lung cancer were above 1.0. Pooling two studies, the OR for any exposure to leaded GEE was 0.82 (0.68-1.00). Our results do not support the hypothesis that occupational exposure to GEE increases the risk of lung cancer. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Cumulative Exposure to Neighborhood Context: Consequences for Health Transitions over the Adult Life Course

PubMed Central

Clarke, Philippa; Morenoff, Jeffrey; Debbink, Michelle; Golberstein, Ezra; Elliott, Michael R.; Lantz, Paula M.

2012-01-01

Over the last two decades, research has assessed the relationship between neighborhood socioeconomic factors and individual health. However, existing research is based almost exclusively on cross-sectional data, ignoring the complexity in health transitions that may be shaped by long term residential exposures. We address these limitations by specifying distinct health transitions over multiple waves of a 15 year study of American adults. We focus on transitions between a hierarchy of health states, (free from health problems, onset of health problems, and death), not just gradients in a single health indicator over time, and use a cumulative measure of exposure to neighborhoods over adulthood. We find that cumulative exposure to neighborhood disadvantage has significant effects on functional decline and mortality. Research ignoring a persons’ history of exposure to residential contexts over the life course runs the risk of underestimating the role of neighborhood disadvantage on health. PMID:24465068

Effect modification of the association of cumulative exposure and cancer risk by intensity of exposure and time since exposure cessation: a flexible method applied to cigarette smoking and lung cancer in the SYNERGY Study.

PubMed

Vlaanderen, Jelle; Portengen, Lützen; Schüz, Joachim; Olsson, Ann; Pesch, Beate; Kendzia, Benjamin; Stücker, Isabelle; Guida, Florence; Brüske, Irene; Wichmann, Heinz-Erich; Consonni, Dario; Landi, Maria Teresa; Caporaso, Neil; Siemiatycki, Jack; Merletti, Franco; Mirabelli, Dario; Richiardi, Lorenzo; Gustavsson, Per; Plato, Nils; Jöckel, Karl-Heinz; Ahrens, Wolfgang; Pohlabeln, Hermann; Tardón, Adonina; Zaridze, David; Field, John K; 't Mannetje, Andrea; Pearce, Neil; McLaughlin, John; Demers, Paul; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Rudnai, Peter; Fabianova, Eleonora; Stanescu Dumitru, Rodica; Bencko, Vladimir; Foretova, Lenka; Janout, Vladimir; Boffetta, Paolo; Forastiere, Francesco; Bueno-de-Mesquita, Bas; Peters, Susan; Brüning, Thomas; Kromhout, Hans; Straif, Kurt; Vermeulen, Roel

2014-02-01

The indiscriminate use of the cumulative exposure metric (the product of intensity and duration of exposure) might bias reported associations between exposure to hazardous agents and cancer risk. To assess the independent effects of duration and intensity of exposure on cancer risk, we explored effect modification of the association of cumulative exposure and cancer risk by intensity of exposure. We applied a flexible excess odds ratio model that is linear in cumulative exposure but potentially nonlinear in intensity of exposure to 15 case-control studies of cigarette smoking and lung cancer (1985-2009). Our model accommodated modification of the excess odds ratio per pack-year of cigarette smoking by time since smoking cessation among former smokers. We observed negative effect modification of the association of pack-years of cigarette smoking and lung cancer by intensity of cigarette smoke for persons who smoked more than 20-30 cigarettes per day. Patterns of effect modification were similar across individual studies and across major lung cancer subtypes. We observed strong negative effect modification by time since smoking cessation. Application of our method in this example of cigarette smoking and lung cancer demonstrated that reducing a complex exposure history to a metric such as cumulative exposure is too restrictive.

Effect Modification of the Association of Cumulative Exposure and Cancer Risk by Intensity of Exposure and Time Since Exposure Cessation: A Flexible Method Applied to Cigarette Smoking and Lung Cancer in the SYNERGY Study

PubMed Central

Vlaanderen, Jelle; Portengen, Lützen; Schüz, Joachim; Olsson, Ann; Pesch, Beate; Kendzia, Benjamin; Stücker, Isabelle; Guida, Florence; Brüske, Irene; Wichmann, Heinz-Erich; Consonni, Dario; Landi, Maria Teresa; Caporaso, Neil; Siemiatycki, Jack; Merletti, Franco; Mirabelli, Dario; Richiardi, Lorenzo; Gustavsson, Per; Plato, Nils; Jöckel, Karl-Heinz; Ahrens, Wolfgang; Pohlabeln, Hermann; Tardón, Adonina; Zaridze, David; Field, John K.; 't Mannetje, Andrea; Pearce, Neil; McLaughlin, John; Demers, Paul; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Rudnai, Peter; Fabianova, Eleonora; Stanescu Dumitru, Rodica; Bencko, Vladimir; Foretova, Lenka; Janout, Vladimir; Boffetta, Paolo; Forastiere, Francesco; Bueno-de-Mesquita, Bas; Peters, Susan; Brüning, Thomas; Kromhout, Hans; Straif, Kurt; Vermeulen, Roel

2014-01-01

The indiscriminate use of the cumulative exposure metric (the product of intensity and duration of exposure) might bias reported associations between exposure to hazardous agents and cancer risk. To assess the independent effects of duration and intensity of exposure on cancer risk, we explored effect modification of the association of cumulative exposure and cancer risk by intensity of exposure. We applied a flexible excess odds ratio model that is linear in cumulative exposure but potentially nonlinear in intensity of exposure to 15 case-control studies of cigarette smoking and lung cancer (1985–2009). Our model accommodated modification of the excess odds ratio per pack-year of cigarette smoking by time since smoking cessation among former smokers. We observed negative effect modification of the association of pack-years of cigarette smoking and lung cancer by intensity of cigarette smoke for persons who smoked more than 20–30 cigarettes per day. Patterns of effect modification were similar across individual studies and across major lung cancer subtypes. We observed strong negative effect modification by time since smoking cessation. Application of our method in this example of cigarette smoking and lung cancer demonstrated that reducing a complex exposure history to a metric such as cumulative exposure is too restrictive. PMID:24355332

[Acute risk assessment of cumulative dietary exposure to organophosphorus pesticide among people in Jiangsu province].

PubMed

Zhao, Minxian; Wang, Cannan; Li, Tingting; Yi, Nannan; He, Xiansong; Wu, Hui; Yao, Xinya

2013-09-01

To understand the cumulative dietary exposure of Jiangsu residents to organophosphorus (OPs) pesticide and make acute risk assessment. Integrated the data of the nutrition and health status of residents in Jiangsu and the data of monitoring of OPs pesticide in agricultural products. Chlorpyrifos was selected as index compound (index chemical, IC), then use relative potency factor (RPF) approach which commended by EPA and simple distribution evaluation. Caloulated the dietary cumulative exposure of OPs pesticide among Jiangsu residents and compared with acute reference dose (ARfD), then made risk assessment. The exposure of rural group of age 3-6 and 7-11 were 133.84 microg/kg BW and 154.32 microg/kg BW, exceeded ARfD. The exposure level of kids and elder was higher than adults. The exposure level of rural residents were higher than urban residents. The highest contribution to the food of each age group was greengrocery and leek. The average level of exposure was safety in Jiangsu, high exposure children were at acute poisoning risk. High contribution food such as greengrocery and leek should be strengthen monitoring.

USING DOSE ADDITION TO ESTIMATE CUMULATIVE RISKS FROM EXPOSURES TO MULTIPLE CHEMICALS

EPA Science Inventory

The Food Quality Protection Act (FQPA) of 1996 requires the EPA to consider the cumulative risk from exposure to multiple chemicals that have a common mechanism of toxicity. Three methods, hazard index (HI), point-of-departure index (PODI), and toxicity equivalence factor (TEF), ...

Prenatal Lead Exposure and Weight of 0- to 5-Year-Old Children in Mexico City

PubMed Central

Peterson, Karen E.; Sánchez, Brisa N.; Cantonwine, David; Lamadrid-Figueroa, Héctor; Schnaas, Lourdes; Ettinger, Adrienne S.; Hernández-Avila, Mauricio; Hu, Howard; Téllez-Rojo, Martha M.

2011-01-01

Background: Cumulative prenatal lead exposure, as measured by maternal bone lead burden, has been associated with smaller weight of offspring at birth and 1 month of age, but no study has examined whether this effect persists into early childhood. Objective: We investigated the association of perinatal maternal bone lead, a biomarker of cumulative prenatal lead exposure, with children’s attained weight over time from birth to 5 years of age. Methods: Children were weighed at birth and at several intervals up until 60 months. Maternal tibia and patella lead were measured at 1 month postpartum using in vivo K-shell X-ray fluorescence. We used varying coefficient models with random effects to assess the association of maternal bone lead with weight trajectories of 522 boys and 477 girls born between 1994 and 2005 in Mexico City. Results: After controlling for breast-feeding duration, maternal anthropometry, and sociodemographic characteristics, a 1-SD increase in maternal patella lead (micrograms per gram) was associated with a 130.9-g decrease in weight [95% confidence interval (CI), –227.4 to –34.4 g] among females and a 13.0-g nonsignificant increase in weight among males (95% CI, –73.7 to 99.9 g) at 5 years of age. These associations were similar after controlling for concurrent blood lead levels between birth and 5 years. Conclusions: Maternal bone lead was associated with lower weight over time among female but not male children up to 5 years of age. Given that the association was evident for patellar but not tibial lead levels, and was limited to females, results need to be confirmed in other studies. PMID:21715242

A study on comparison of Gafchromic EBT2 film response under single and cumulative exposure conditions

PubMed Central

Ganapathy, K.; Kurup, P.G.G.; Murali, V.; Muthukumaran, M.; Velmurugan, J.

2013-01-01

Gafchromic films are used as dosimeter for in vivo and in phantom dose measurements. The dose response of Gafchromic EBT2 film under single and repeated exposure conditions is compared in this study to analyze the usability of Gafchromic EBT2 films in cumulative dose measurements. The post-irradiation change in response of the film is studied for up to 4 days after irradiation. The effect of repeated exposure to scanner light on the response of the film is also studied. To check usability of Gafchromic EBT2 films in cumulative dose measurements, three EBT2 films were exposed to a daily fraction dose of 100 cGy, 150 cGy and 200 cGy, respectively, for 4 days. The dose response of the films exposed to cumulative irradiation was compared with the dose measured from films exposed to the same dose but in a single exposure. It is observed that the post-irradiation darkening of the film does not saturate and continue to take place even 4 days after irradiation. The dose measured from the EBT2 films after 4 days from irradiation was around 2% higher than the dose measured from the same films at 24 hours post-irradiation. It was also observed that the repeated exposure to scanner light does not produce any significant change in the film response. The dose response of films exposed to cumulative irradiation agrees with the dose response of films exposed to the same dose in a single irradiation with less than 3% difference. Gafchromic EBT2 films can be used to measure the cumulative dose delivered over multiple fractions, when the delivered dose is uniform across the film. PMID:24672151

Head Impact Exposure in Youth Football: High School Ages 14 to 18 Years and Cumulative Impact Analysis

PubMed Central

Urban, Jillian E.; Davenport, Elizabeth M.; Golman, Adam J.; Maldjian, Joseph A.; Whitlow, Christopher T.; Powers, Alexander K.; Stitzel, Joel D.

2015-01-01

Sports-related concussion is the most common athletic head injury with football having the highest rate among high school athletes. Traditionally, research on the biomechanics of football-related head impact has been focused at the collegiate level. Less research has been performed at the high school level, despite the incidence of concussion among high school football players. The objective of this study is to twofold: to quantify the head impact exposure in high school football, and to develop a cumulative impact analysis method. Head impact exposure was measured by instrumenting the helmets of 40 high school football players with helmet mounted accelerometer arrays to measure linear and rotational acceleration. A total of 16,502 head impacts were collected over the course of the season. Biomechanical data were analyzed by team and by player. The median impact for each player ranged from 15.2 to 27.0 g with an average value of 21.7 (±2.4) g. The 95th percentile impact for each player ranged from 38.8 to 72.9 g with an average value of 56.4 (±10.5) g. Next, an impact exposure metric utilizing concussion injury risk curves was created to quantify cumulative exposure for each participating player over the course of the season. Impacts were weighted according to the associated risk due to linear acceleration and rotational acceleration alone, as well as the combined probability (CP) of injury associated with both. These risks were summed over the course of a season to generate risk weighted cumulative exposure. The impact frequency was found to be greater during games compared to practices with an average number of impacts per session of 15.5 and 9.4, respectively. However, the median cumulative risk weighted exposure based on combined probability was found to be greater for practices vs. games. These data will provide a metric that may be used to better understand the cumulative effects of repetitive head impacts, injury mechanisms, and head impact exposure of

[Lead exposure of people living in a lead high exposure area from local diet].

PubMed

Zhou, Yong; He, Liping; Huang, Xiao; He, Junshan

2011-11-01

To study the lead exposure of people living in a lead high exposure area from local diet, and to assess its health risks. Thirty five subjects were selected by random from a mining area and another 30 subjects were selected from a non-polluted area. The exposure of lead was estimated by the content of lead in drinking water and vegetables, and health risks was estimated by the levels of lead in blood and urine. The content of lead in drinking water and vegetables in the mining area was 20.6 microg/L and 1.61mg/kg (geometric mean) respectively, which were higher than that in the unpolluted area (6.0 microg/L and 0.56 mg/kg, geometric mean) (P < 0.01). The daily lead exposure of male and female inhabitants in the mining area from diet was 16.88 microg/kg and 16.09 microg/kg respectively, which was higher than that in the unpolluted area (P < 0.01), but the sex difference was not significant statistically (P > 0.05). Blood lead and urine lead of inhabitants in the mining-area were higher than those in the unpolluted area. The health risks for male and female inhabitants in the mining area were 4.73 and 4.51. The health risks of lead exposure caused by diet (drinking water and food) were relatively high in the mining area.

Calibrating a population-based job-exposure matrix using inspection measurements to estimate historical occupational exposure to lead for a population-based cohort in Shanghai, China

PubMed Central

Koh, Dong-Hee; Bhatti, Parveen; Coble, Joseph B.; Stewart, Patricia A; Lu, Wei; Shu, Xiao-Ou; Ji, Bu-Tian; Xue, Shouzheng; Locke, Sarah J.; Portengen, Lutzen; Yang, Gong; Chow, Wong-Ho; Gao, Yu-Tang; Rothman, Nathaniel; Vermeulen, Roel; Friesen, Melissa C.

2012-01-01

The epidemiologic evidence for the carcinogenicity of lead is inconsistent and requires improved exposure assessment to estimate risk. We evaluated historical occupational lead exposure for a population-based cohort of women (n=74,942) by calibrating a job-exposure matrix (JEM) with lead fume (n=20,084) and lead dust (n=5,383) measurements collected over four decades in Shanghai, China. Using mixed-effect models, we calibrated intensity JEM ratings to the measurements using fixed-effects terms for year and JEM rating. We developed job/industry-specific estimates from the random-effects terms for job and industry. The model estimates were applied to subjects’ jobs when the JEM probability rating was high for either job or industry; remaining jobs were considered unexposed. The models predicted that exposure increased monotonically with JEM intensity rating and decreased 20–50-fold over time. The cumulative calibrated JEM estimates and job/industry-specific estimates were highly correlated (Pearson correlation=0.79–0.84). Overall, 5% of the person-years and 8% of the women were exposed to lead fume; 2% of the person-years and 4% of the women were exposed to lead dust. The most common lead-exposed jobs were manufacturing electronic equipment. These historical lead estimates should enhance our ability to detect associations between lead exposure and cancer risk in future epidemiologic analyses. PMID:22910004

How to quantify exposure to traumatic stress? Reliability and predictive validity of measures for cumulative trauma exposure in a post-conflict population.

PubMed

Wilker, Sarah; Pfeiffer, Anett; Kolassa, Stephan; Koslowski, Daniela; Elbert, Thomas; Kolassa, Iris-Tatjana

2015-01-01

While studies with survivors of single traumatic experiences highlight individual response variation following trauma, research from conflict regions shows that almost everyone develops posttraumatic stress disorder (PTSD) if trauma exposure reaches extreme levels. Therefore, evaluating the effects of cumulative trauma exposure is of utmost importance in studies investigating risk factors for PTSD. Yet, little research has been devoted to evaluate how this important environmental risk factor can be best quantified. We investigated the retest reliability and predictive validity of different trauma measures in a sample of 227 Ugandan rebel war survivors. Trauma exposure was modeled as the number of traumatic event types experienced or as a score considering traumatic event frequencies. In addition, we investigated whether age at trauma exposure can be reliably measured and improves PTSD risk prediction. All trauma measures showed good reliability. While prediction of lifetime PTSD was most accurate from the number of different traumatic event types experienced, inclusion of event frequencies slightly improved the prediction of current PTSD. As assessing the number of traumatic events experienced is the least stressful and time-consuming assessment and leads to the best prediction of lifetime PTSD, we recommend this measure for research on PTSD etiology.

Beyond the job exposure matrix (JEM): the task exposure matrix (TEM).

PubMed

Benke, G; Sim, M; Fritschi, L; Aldred, G

2000-09-01

The job exposure matrix (JEM) has been employed to assign cumulative exposure to workers in many epidemiological studies. In these studies, where quantitative data are available, all workers with the same job title and duration are usually assigned similar cumulative exposures, expressed in mgm(-3)xyears. However, if the job is composed of multiple tasks, each with its own specific exposure profile, then assigning all workers within a job the same mean exposure can lead to misclassification of exposure. This variability of exposure within job titles is one of the major weaknesses of JEMs. A method is presented for reducing the variability in the JEM methodology, which has been called the task exposure matrix (TEM). By summing the cumulative exposures of a worker over all the tasks worked within a job title, it is possible to address the variability of exposure within the job title, and reduce possible exposure misclassification. The construction of a TEM is outlined and its application in the context of a study in the primary aluminium industry is described. The TEM was found to assign significantly different cumulative exposures to the majority of workers in the study, compared with the JEM and the degree of difference in cumulative exposure between the JEM and the TEM varied greatly between contaminants.

DETERMINANTS OF RESIDENTIAL LEAD EXPOSURE

EPA Science Inventory

The phase-out of leaded gasoline, and the accompanying decrease in lead emissions, resulted in a dramatic decline in mean blood lead levels from the late 1970s through the early 1990s. Nonetheless, lead exposures remain a public health concern. Long-term exposures to even low...

Cumulative exposure to prior collective trauma and acute stress responses to the Boston marathon bombings.

PubMed

Garfin, Dana Rose; Holman, E Alison; Silver, Roxane Cohen

2015-06-01

The role of repeated exposure to collective trauma in explaining response to subsequent community-wide trauma is poorly understood. We examined the relationship between acute stress response to the 2013 Boston Marathon bombings and prior direct and indirect media-based exposure to three collective traumatic events: the September 11, 2001 (9/11) terrorist attacks, Superstorm Sandy, and the Sandy Hook Elementary School shooting. Representative samples of residents of metropolitan Boston (n = 846) and New York City (n = 941) completed Internet-based surveys shortly after the Boston Marathon bombings. Cumulative direct exposure and indirect exposure to prior community trauma and acute stress symptoms were assessed. Acute stress levels did not differ between Boston and New York metropolitan residents. Cumulative direct and indirect, live-media-based exposure to 9/11, Superstorm Sandy, and the Sandy Hook shooting were positively associated with acute stress responses in the covariate-adjusted model. People who experience multiple community-based traumas may be sensitized to the negative impact of subsequent events, especially in communities previously exposed to similar disasters. © The Author(s) 2015.

End-stage renal disease after occupational lead exposure: 20 years of follow-up.

PubMed

Evans, Marie; Discacciati, Andrea; Quershi, Abdul Rashid; Åkesson, Agneta; Elinder, Carl-Gustaf

2017-06-01

Whether low-level exposure to lead may give rise to chronic kidney disease or end-stage renal disease (ESRD) is debated. In this study, we aimed to specifically investigate if low-level occupational exposure to lead was associated with increased incidence of ESRD. The incidence of starting renal replacement therapy as a result of ESRD was examined in a cohort of10 303 lead-workers who had controlled blood lead concentrations due to a compulsory occupational health surveillance programme in Sweden during the time period 1977-1990. The ESRD incidence (obtained through register-linkage) among the lead-exposed workers was compared with the age, sex and calendar period-adjusted expected incidence based on data from the Swedish renal registry. Dose-response association was evaluated in external (general population) and internal (within the occupational cohort) comparisons by highest achieved blood lead level. There were 30 (0.29%) individuals in the cohort who developed ESRD during the median follow-up period of 26.3 years. The standardised incidence ratio (SIR) for ESRD incidence was 0.79 (95% CI 0.54 to 1.13). Among those who achieved the highest blood lead (>41.4 µg/dL), the SIR was 1.01 (0.44 to 1.99). There was no evidence of a dose-response relationship between the maximum achieved blood lead or the cumulative blood lead exposure and ESRD in external or internal comparisons. This study of workers with documented occupational lead exposures followed for 20 years shows no statistically significant association between lead exposure (following the current occupational recommendations for Sweden) and ESRD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Current and historical individual data about exposure of workers in the rayon industry to carbon disulfide and their validity in calculating the cumulative dose.

PubMed

Göen, Thomas; Schramm, Axel; Baumeister, Thomas; Uter, Wolfgang; Drexler, Hans

2014-08-01

The objective of the study was to investigate how exposure to carbon disulfide (CS2) in a rayon-manufacturing plant has changed within two decades and whether it is possible to calculate valid data for the individual cumulative exposure. The data for CS2 concentration in air and biological exposure monitoring (2-thio-1,3-thiaxolidine-4-carboxylic acid (TTCA) in urine) from two cross-sectional studies, performed in 1992 (n = 362) and 2009 (n = 212) in a German rayon-manufacturing plant, were compared to data obtained from company-internal measurements between the studies. Using the data from the cross-sectional studies and company-internal data, cumulative external exposure and the cumulative internal exposure were calculated for each worker. External and internal CS2 exposure of the employees decreased from 1992 (medians 4.0 ppm and 1.63 mgTTCA/g creatinine) to 2009 (medians 2.5 ppm and 0.86 mg/g). However, company-internal CS2 data do not show a straight trend for this period. The annual medians of the company-internal measurement of external exposure to CS2 have varied between 2.7 and 8.4 ppm, in which median values exceeded 5 ppm generally since 2000. The annual medians for the company-internal biomonitoring assessment ranged between 1.2 and 2.8 mg/g creatinine. The cumulative CS2 exposure ranged from 8.5 to 869.5 ppm years for external exposure and between 1.30 and 176.2 mg/g creatinine years for the internal exposure. Significant correlations were found between the current air pollution and the internal exposure in 2009 but also between the cumulative external and internal CS2 exposure. Current exposure data, usually collected in cross-sectional studies, rarely allow a reliable statement on the cumulative dose, because of higher exposure in the past and of fluctuating courses of exposure. On the other hand, company-internal exposure data may be affected by non-representative measurement strategies. Some verification of the reliability of

DEVELOPMENT AND VALIDATION OF THE CUMULATIVE ENVIRONMENTAL EXPOSURE INDEX FOR ARSENIC: A NOVEL ENVIRONMENTAL PUBLIC HEALTH INDICATOR

EPA Science Inventory

Arsenic (As) is a ubiquitous environmental toxin that causes a wide range of diseases. To date, however, there is no methodology for calculating the impact of cumulative As exposure on health outcomes in the US. The current project will develop and validate the Cumulative Envi...

Long-term exposure to high air pollution induces cumulative DNA damages in traffic policemen.

PubMed

Tan, Chaochao; Lu, Shijie; Wang, Yupeng; Zhu, Yan; Shi, Ting; Lin, Mingyue; Deng, Zhonghua; Wang, Zhu; Song, Nana; Li, Shuna; Yang, Pingting; Yang, Liyan; Liu, Yuanyuan; Chen, Zhiheng; Xu, Keqian

2017-09-01

The specific effects of long-term exposure to high air pollution on human health and biological remain unclear. To explore the adverse health effects as well as biological mechanisms and biomarkers for durative exposure to air pollution, 183 traffic policemen and 88 office policemen were enrolled in this study. The concentration of PM2.5 in both the traffic and office policemen's working environments were obtained. Detailed personal questionnaires were completed and levels of inflammation, oxidative stress and DNA damage markers of all participants were analyzed in this study. The average PM2.5 concentration of the intersections of main roads and the offices of control group were 132.4±48.9μg/m 3 and 50.80±38.6μg/m 3 , respectively. The traffic policemen, who stably exposed to at least 2 times higher PM2.5 in their work area as compared with the control group, have a median average duration of 7.00years, and average cumulative intersection duty time reached 8030h. No statistically significant differences in the levels of inflammation markers were observed between the traffic and office policemen. However, the DNA damage markers in traffic policemen shared significant positive correlation with cumulative intersection duty time and higher than those in the office policemen. Multiple linear regression analysis demonstrated that the increase of cumulative intersection duty time by 1h per day for one year was associated with the increase in 8-hydroxy-20-deoxyguanosine of 0.329% (95% CI: 0.249% to 0.409%), tail DNA of 0.051% (95% CI: 0.041% to 0.061%), micronucleus frequency of 0.036‰ (95% CI: 0.03‰ to 0.043‰), and a decrease in glutathione of 0.482% (95% CI: -0.652% to -0.313%). These findings suggest that long-term exposure to high air pollution could induce cumulative DNA damages, supporting the hypothesis that durative exposure to air pollution is associated with an increased risk of cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

Iron Metabolism Genes, Low-Level Lead Exposure, and QT Interval

PubMed Central

Park, Sung Kyun; Hu, Howard; Wright, Robert O.; Schwartz, Joel; Cheng, Yawen; Sparrow, David; Vokonas, Pantel S.; Weisskopf, Marc G.

2009-01-01

Background Cumulative exposure to lead has been shown to be associated with depression of electrocardiographic conduction, such as QT interval (time from start of the Q wave to end of the T wave). Because iron can enhance the oxidative effects of lead, we examined whether polymorphisms in iron metabolism genes [hemochromatosis (HFE), transferrin (TF) C2, and heme oxygenase-1 (HMOX-1)] increase susceptibility to the effects of lead on QT interval in 613 community-dwelling older men. Methods We used standard 12-lead electrocardiograms, K-shell X-ray fluorescence, and graphite furnace atomic absorption spectrometry to measure QT interval, bone lead, and blood lead levels, respectively. Results A one-interquartile-range increase in tibia lead level (13 μg/g) was associated with a 11.35-msec [95% confidence interval (CI), 4.05–18.65 msec] and a 6.81-msec (95% CI, 1.67–11.95 msec) increase in the heart-rate–corrected QT interval among persons carrying long HMOX-1 alleles and at least one copy of an HFE variant, respectively, but had no effect in persons with short and middle HMOX-1 alleles and the wild-type HFE genotype. The lengthening of the heart-rate–corrected QT interval with higher tibia lead and blood lead became more pronounced as the total number (0 vs. 1 vs. ≥2) of gene variants increased (tibia, p-trend = 0.01; blood, p-trend = 0.04). This synergy seems to be driven by a joint effect between HFE variant and HMOX-1 L alleles. Conclusion We found evidence that gene variants related to iron metabolism increase the impacts of low-level lead exposure on the prolonged QT interval. This is the first such report, so these results should be interpreted cautiously and need to be independently verified. PMID:19165391

DOSE-RESPONSE MODELING FOR THE ASSESSMENT OF CUMULATIVE RISK DUE TO EXPOSURE TO N-METHYL CARBAMATE PESTICIDES

EPA Science Inventory

The US EPAs N-Methyl Carbamate Cumulative Risk Assessment (NMCRA) assesses the effect on acetylcholine esterase (AChE) activity of exposure to 10 N-methyl carbamate (NMC) pesticides through dietary, drinking water, and residential exposures.

Cumulative exposure to dust and gases as determinants of lung function decline in tunnel construction workers

PubMed Central

Bakke, B; Ulvestad, B; Stewart, P; Eduard, W

2004-01-01

Aims: To study the relation between lung function decrease and cumulative exposure to dust and gases in tunnel construction workers. Methods: A total of 651 male construction workers (drill and blast workers, tunnel concrete workers, shotcreting operators, and tunnel boring machine workers) were followed up by spirometric measurements in 1989–2002 for an average of six years. Outdoor concrete workers, foremen, and engineers served as a low exposed referent population. Results: The between worker component of variability was considerably reduced within the job groups compared to the whole population, suggesting that the workers within job groups had similar exposure levels. The annual decrease in FEV1 in low-exposed non-smoking workers was 21 ml and 24 ml in low-exposed ever smokers. The annual decrease in FEV1 in tunnel construction workers was 20–31 ml higher than the low exposed workers depending on job group for both non-smokers and ever smokers. After adjustment for age and observation time, cumulative exposure to nitrogen dioxide showed the strongest association with a decrease in FEV1 in both non-smokers, and ever smokers. Conclusion: Cumulative exposure to nitrogen dioxide appeared to be a major risk factor for lung function decreases in these tunnel construction workers, although other agents may have contributed to the observed effect. Contact with blasting fumes should be avoided, diesel exhaust emissions should be reduced, and respiratory devices should be used to protect workers against dust and nitrogen dioxide exposure. PMID:14985522

EPA's SHEDS-multimedia model: children's cumulative pyrethroid exposure estimates and evaluation against NHANES biomarker data.

PubMed

Xue, Jianping; Zartarian, Valerie; Tornero-Velez, Rogelio; Tulve, Nicolle S

2014-12-01

The U.S. EPA's SHEDS-Multimedia model was applied to enhance the understanding of children's exposures and doses to multiple pyrethroid pesticides, including major contributing chemicals and pathways. This paper presents combined dietary and residential exposure estimates and cumulative doses for seven commonly used pyrethroids, and comparisons of model evaluation results with NHANES biomarker data for 3-PBA and DCCA metabolites. Model input distributions were fit to publicly available pesticide usage survey data, NHANES, and other studies, then SHEDS-Multimedia was applied to estimate total pyrethroid exposures and doses for 3-5 year olds for one year variability simulations. For dose estimations we used a pharmacokinetic model and two approaches for simulating dermal absorption. SHEDS-Multimedia predictions compared well to NHANES biomarker data: ratios of 3-PBA observed data to SHEDS-Multimedia modeled results were 0.88, 0.51, 0.54 and 1.02 for mean, median, 95th, and 99th percentiles, respectively; for DCCA, the ratios were 0.82, 0.53, 0.56, and 0.94. Modeled time-averaged cumulative absorbed dose of the seven pyrethroids was 3.1 nmol/day (versus 8.4 nmol/day for adults) in the general population (residential pyrethroid use and non-use homes) and 6.7 nmol/day (versus 10.5 nmol/day for adults) in the simulated residential pyrethroid use population. For the general population, contributions to modeled cumulative dose by chemical were permethrin (60%), cypermethrin (22%), and cyfluthrin (16%); for residential use homes, contributions were cypermethrin (49%), permethrin (29%), and cyfluthrin (17%). The primary exposure route for 3-5 year olds in the simulated residential use population was non-dietary ingestion exposure; whereas for the simulated general population, dietary exposure was the primary exposure route. Below the 95th percentile, the major exposure pathway was dietary for the general population; non-dietary ingestion was the major pathway starting below

Cumulative risk exposure moderates the association between parasympathetic reactivity and inhibitory control in preschool-age children.

PubMed

Giuliano, Ryan J; Roos, Leslie E; Farrar, Jessica D; Skowron, Elizabeth A

2018-04-01

A child's cumulative risk for early exposure to stress has been linked to alterations of self-regulation outcomes, including neurobiological correlates of inhibitory control (IC). We examined whether children's ability to engage the parasympathetic nervous system impacts how risk affects IC. Children ages 3-5 years completed two laboratory measures of IC while respiratory sinus arrhythmia (RSA) was measured, indexing parasympathetic activity. Children with greater risk demonstrated lower IC; risk also moderated associations between RSA reactivity and IC. For children with less risk, greater RSA withdrawal during IC tasks was associated with better IC. In contrast, greater risk was associated with poor IC, regardless of RSA withdrawal. Effects of risk were more pronounced for cumulative than individual measures. Results suggest that cumulative risk exposure disrupts connectivity between physiological and behavioral components of self-regulation in early childhood. Parasympathetic withdrawal to cognitive tasks may be less relevant for performance in developmental samples experiencing greater life stress. © 2018 Wiley Periodicals, Inc.

Shape memory polymer sensors for tracking cumulative environmental exposure

NASA Astrophysics Data System (ADS)

Snyder, Ryan; Rauscher, Michael; Vining, Ben; Havens, Ernie; Havens, Teresa; McFerran, Jace

2010-04-01

Cornerstone Research Group Inc. (CRG) has developed environmental exposure tracking (EET) sensors using shape memory polymers (SMP) to monitor the degradation of perishable items, such as munitions, foods and beverages, or medicines, by measuring the cumulative exposure to temperature and moisture. SMPs are polymers whose qualities have been altered to give them dynamic shape "memory" properties. Under thermal or moisture stimuli, the SMP exhibits a radical change from a rigid thermoset to a highly flexible, elastomeric state. The dynamic response of the SMP can be tailored to match the degradation profile of the perishable item. SMP-based EET sensors require no digital memory or internal power supply and provide the capability of inexpensive, long-term life cycle monitoring of thermal and moisture exposure over time. This technology was developed through Phase I and Phase II SBIR efforts with the Navy. The emphasis of current research centers on transitioning SMP materials from the lab bench to a production environment. Here, CRG presents the commercialization progress of thermally-activated EET sensors, focusing on fabrication scale-up, process refinements, and quality control. In addition, progress on the development of vapor pressure-responsive SMP (VPR-SMP) will be discussed.

Cumulative effects of exposure to violence on posttraumatic stress in Palestinian and Israeli youth.

PubMed

Dubow, Eric F; Boxer, Paul; Huesmann, L Rowell; Landau, Simha; Dvir, Shira; Shikaki, Khalil; Ginges, Jeremy

2012-01-01

We examine cumulative and prospective effects of exposure to conflict and violence across four contexts (ethnic-political, community, family, school) on posttraumatic stress (PTS) symptoms in Palestinian and Israeli youth. Interviews were conducted with 600 Palestinian and 901 Israeli (Jewish and Arab) children (ages 8, 11, and 14) and their parents once a year for 3 consecutive years. Palestinian children, males, and older youth were generally at greatest risk for exposure to conflict/violence across contexts. Regression analysis found unique effects of exposure to ethnic-political (Palestinian sample), school (Palestinian and Israeli Jewish samples), and family conflict/violence (Israeli Arab sample) during the first 2 years on PTS symptoms in Year 3, controlling for prior PTS symptoms. Cumulative exposure to violence in more contexts during the first 2 years predicted higher subsequent PTS symptoms than did exposure to violence in fewer contexts, and this was true regardless of the youth's level of prior PTS symptoms. These results highlight the risk that ongoing exposure to violence across multiple contexts in the social ecology poses for the mental health of children in contexts of ethnic-political violence. Researchers and mental health professionals working with war-exposed youth in a given cultural context must assess both war- and non-war-related stressors affecting youth. Based on this assessment, interventions may not be limited to individual-based, war-trauma-focused approaches but also may include school-based, community-based, and family-level interventions.

Effect of cumulative exposure to corticosteroid and DMARD on radiographic progression in rheumatoid arthritis: results from the ESPOIR cohort.

PubMed

Louveau, Baptiste; De Rycke, Yann; Lafourcade, Alexandre; Saraux, Alain; Guillemin, Francis; Tubach, Florence; Fautrel, Bruno; Hajage, David

2018-05-22

Several authors have tried to predict the risk of radiographic progression in RA according to baseline characteristics, considering exposure to treatment only as a binary variable (Treated: Yes/No). This study aims to model the risk of 5-year radiographic progression taking into account both baseline characteristics and the cumulative time-varying exposure to corticosteroids or DMARDs. The study population consisted of 403 patients of the Etude et Suivi des Polyarthrites Indifférenciées Récentes cohort meeting the 1987 ACR or 2010 ACR/EULAR criteria for RA at inclusion and having complete radiographic data at baseline and 5 years. Radiographic progression was defined at 5 years as a significant increase of the Sharp/van der Heidje score (smallest detectable difference ⩾5). The best logistic regression model was selected from the following: model including only clinico-biological baseline characteristics; model considering baseline characteristics and treatments as binary variables; and model considering baseline characteristics and treatments as weighted cumulative exposure variables. Radiographic progression occurred in 143 (35.5%) patients. The best model combined anti-citrullinated peptide antibody positivity, ESR, swollen joint count >14 and erosion score at baseline, as well as corticosteroids, MTX/LEF (MTX or LEF) and biologic DMARDs (bDMARDs) as weighted cumulative exposure variables. Recent cumulative exposure to high doses of corticosteroids (⩽ 3months) was significantly associated with the risk of 5-year radiographic progression and a significant protective association was highlighted for a 36-month exposure to bDMARDs. Corticosteroids and bDMARDs play an important role in radiographic progression. Accounting for treatment class and intensity of exposure is a major concern in predictive models of radiographic progression in RA patients.

Cumulative occupational mechanical exposures during working life and risk of sickness absence and disability pension: prospective cohort study.

PubMed

Sundstrup, Emil; Hansen, Åse Marie; Mortensen, Erik Lykke; Poulsen, Otto Melchior; Clausen, Thomas; Rugulies, Reiner; Møller, Anne; Andersen, Lars L

2017-09-01

Objectives The aim of this study was to determine the prospective association of cumulative mechanical exposure during working life with health-related labor market outcomes. Methods This prospective cohort study combines data from 5076 older workers (age 49-63 years) from the Copenhagen Aging and Midlife Biobank with a job exposure matrix and a national register containing information on social transfer payment. By coding individual job histories from the Danish version of ISCO-codes (International Standard Classification of Occupations), we calculated cumulative occupational mechanical exposures from a JEM for ton-years (lifting 1000 kg each day in one year), lifting-years (lifting loads weighing ≥20 kg >10 times each day in one year), kneeling-years (kneeling for one hour each day in one year) and vibration-years (whole-body vibration for one hour each day in one year). Cox-regression analyses estimated the relative risk of register-based long-term sickness absence (LTSA) and disability pension with cumulative occupational mechanical exposures throughout working life. Analyses were censored for competing events and adjusted for multiple confounders. Results During the follow-up period, 970 persons (19.3%) had ≥1 episode of LTSA and 85 persons (1.7%) were granted a disability pension. Number of ton-, lifting- and kneeling-years showed an exposure-response association with increased risk of LTSA (P<0.0001). In addition, both long term [≥20 years; hazard ratio (HR) 1.76 95% CI 1.39-2.22] and short term (<10 years; HR 1.20 95% CI 1.02-1.41) exposure to kneeling work increased the risk of LTSA. Lifting-years, but not the other mechanical exposures, were associated with risk of disability pension (HR 1.75 95% CI 1.01-3.04). Conclusions Cumulative occupational mechanical exposures during working life - such as lifting and kneeling work - increased the risk of LTSA. Importantly, being exposed to lifting increased the risk of disability pension.

Tracking Cumulative Radiation Exposure in Orthopaedic Surgeons and Residents: What Dose Are We Getting?

PubMed

Gausden, Elizabeth B; Christ, Alexander B; Zeldin, Roseann; Lane, Joseph M; McCarthy, Moira M

2017-08-02

The purpose of this study was to determine the amount of cumulative radiation exposure received by orthopaedic surgeons and residents in various subspecialties. We obtained dosimeter measures over 12 months on 24 residents and 16 attending surgeons. Monthly radiation exposure was measured over a 12-month period for 24 orthopaedic residents and 16 orthopaedic attending surgeons. The participants wore a Landauer Luxel dosimeter on the breast pocket of their lead apron. The dosimeters were exchanged every rotation (5 to 7 weeks) for the resident participants and every month for the attending surgeon participants. Radiation exposure was compared by orthopaedic subspecialty, level of training, and type of fluoroscopy used (regular C-arm compared with mini C-arm). Orthopaedic residents participating in this study received monthly mean radiation exposures of 0.2 to 79 mrem/month, lower than the dose limits of 5,000 mrem/year recommended by the United States Nuclear Regulatory Commission (U.S. NRC). Senior residents rotating on trauma were exposed to the highest monthly radiation (79 mrem/month [range, 15 to 243 mrem/month]) compared with all other specialty rotations (p < 0.001). Similarly, attending orthopaedic surgeons who specialize in trauma or deformity surgery received the highest radiation exposure of their peers, and the mean exposure was 53 mrem/month (range, 0 to 355 mrem/month). Residents and attending surgeons performing trauma or deformity surgical procedures are exposed to significantly higher doses of radiation compared with all other subspecialties within orthopaedic surgery, but the doses are still within the recommended limits. The use of ionizing radiation in the operating room has become an indispensable part of orthopaedic surgery. Although all surgeons in our study received lower than the yearly recommended dose limit, it is important to be aware of how much radiation we are exposed to as surgeons and to take measures to further limit that exposure.

HEALTH AND ENVIRONMENTAL SCIENCES INSTITUTE'S EXPOSURE FACTORS DATABASE FOR AGGREGATE AND CUMULATIVE RISK ASSESSMENT

EPA Science Inventory

In recent years, the risk analysis community has broadened its use of complex aggregate and cumulative residential exposure models (e.g., to meet the requirements of the 1996 Food Quality Protection Act). The value of these models is their ability to incorporate a range of input...

Evaluating Exposure-Response Associations for Non-Hodgkin Lymphoma with Varying Methods of Assigning Cumulative Benzene Exposure in the Shanghai Women's Health Study.

PubMed

Friesen, Melissa C; Bassig, Bryan A; Vermeulen, Roel; Shu, Xiao-Ou; Purdue, Mark P; Stewart, Patricia A; Xiang, Yong-Bing; Chow, Wong-Ho; Ji, Bu-Tian; Yang, Gong; Linet, Martha S; Hu, Wei; Gao, Yu-Tang; Zheng, Wei; Rothman, Nathaniel; Lan, Qing

2017-01-01

To provide insight into the contributions of exposure measurements to job exposure matrices (JEMs), we examined the robustness of an association between occupational benzene exposure and non-Hodgkin lymphoma (NHL) to varying exposure assessment methods. NHL risk was examined in a prospective population-based cohort of 73087 women in Shanghai. A mixed-effects model that combined a benzene JEM with >60000 short-term, area benzene inspection measurements was used to derive two sets of measurement-based benzene estimates: 'job/industry-specific' estimates (our presumed best approach) were derived from the model's fixed effects (year, JEM intensity rating) and random effects (occupation, industry); 'calibrated JEM' estimates were derived using only the fixed effects. 'Uncalibrated JEM' (using the ordinal JEM ratings) and exposure duration estimates were also calculated. Cumulative exposure for each subject was calculated for each approach based on varying exposure definitions defined using the JEM's probability ratings. We examined the agreement between the cumulative metrics and evaluated changes in the benzene-NHL associations. For our primary exposure definition, the job/industry-specific estimates were moderately to highly correlated with all other approaches (Pearson correlation 0.61-0.89; Spearman correlation > 0.99). All these metrics resulted in statistically significant exposure-response associations for NHL, with negligible gain in model fit from using measurement-based estimates. Using more sensitive or specific exposure definitions resulted in elevated but non-significant associations. The robust associations observed here with varying benzene assessment methods provide support for a benzene-NHL association. While incorporating exposure measurements did not improve model fit, the measurements allowed us to derive quantitative exposure-response curves. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2017.

Childhood Poverty, Cumulative Risk Exposure, and Mental Health in Emerging Adults

PubMed Central

Evans, Gary W.; Cassells, Rochelle C.

2014-01-01

One out of four American children are born into poverty, but little is known about the long-term, mental health implications of early deprivation. The more time in poverty from birth-age-9, the worse mental health as emerging adults (n = 196, M = 17.30 years, 53% male). These results maintain independently of concurrent, adult income levels for self-reported externalizing symptoms and a standard learned helplessness behavioral protocol, but internalizing symptoms were unaffected by childhood poverty. We then demonstrate that part of the reason why early poverty exposure is harmful to mental health among emerging adults is because of elevated cumulative risk exposure assessed at age 13. The significant, prospective, longitudinal relations between early childhood poverty and externalizing symptoms plus learned helplessness behavior are mediated, in part, by exposure to a confluence of psychosocial (violence, family turmoil, child separation from family) and physical (noise, crowding, substandard housing) risk factors during adolescence. PMID:26609499

Lead exposure in US worksites: A literature review and development of an occupational lead exposure database from the published literature

PubMed Central

Koh, Dong-Hee; Locke, Sarah J.; Chen, Yu-Cheng; Purdue, Mark P.; Friesen, Melissa C.

2016-01-01

Background Retrospective exposure assessment of occupational lead exposure in population-based studies requires historical exposure information from many occupations and industries. Methods We reviewed published US exposure monitoring studies to identify lead exposure measurement data. We developed an occupational lead exposure database from the 175 identified papers containing 1,111 sets of lead concentration summary statistics (21% area air, 47% personal air, 32% blood). We also extracted ancillary exposure-related information, including job, industry, task/location, year collected, sampling strategy, control measures in place, and sampling and analytical methods. Results Measurements were published between 1940 and 2010 and represented 27 2-digit standardized industry classification codes. The majority of the measurements were related to lead-based paint work, joining or cutting metal using heat, primary and secondary metal manufacturing, and lead acid battery manufacturing. Conclusions This database can be used in future statistical analyses to characterize differences in lead exposure across time, jobs, and industries. PMID:25968240

(BOSC) DOSE-RESPONSE MODELING FOR THE ASSESSMENT OF CUMULATIVE RISK DUE TO EXPOSURE TO N-METHYL CARBAMATE PRESTICIDES

EPA Science Inventory

THE US EPA'S N-METHYL CARBAMATE CUMULATIVE RISK ASSESSMENT (NMCRA) ASSESSES THE EFFECT ON ACETYLCHOLINE ESTERASE (AChE) ACTIVITY OF EXPOSURE TO 10 N-METHLY CARBAMATE (NMC)PESTICIDES THROUGH DIETARY, DRINKING WATER, AND RESIDENTIAL EXPOSURES. THESE DATA THUS INFORM, BUT DO NOT COM...

Cumulative Effects of Exposure to Violence on Posttraumatic Stress in Palestinian and Israeli Youth

ERIC Educational Resources Information Center

Dubow, Eric F.; Boxer, Paul; Huesmann, L. Rowell; Landau, Simha; Dvir, Shira; Shikaki, Khalil; Ginges, Jeremy

2012-01-01

We examine cumulative and prospective effects of exposure to conflict and violence across four contexts (ethnic-political, community, family, school) on posttraumatic stress (PTS) symptoms in Palestinian and Israeli youth. Interviews were conducted with 600 Palestinian and 901 Israeli (Jewish and Arab) children (ages 8, 11, and 14) and their…

The injury and cumulative effects on human skin by UV exposure from artificial fluorescence emission.

PubMed

Tian, Yan; Liu, Wei; Niu, TianHui; Dai, CaiHong; Li, Xiaoxin; Cui, Caijuan; Zhao, Xinyan; E, Yaping; Lu, Hui

2014-01-01

The injury and cumulative effects of UV emission from fluorescence lamp were studied. UV intensity from fluorescence lamp was measured, and human skin samples (hips, 10 volunteers) were exposed to low-dose UV irradiation (three times per week for 13 consecutive weeks). Three groups were examined: control group without UV radiation; low-dose group with a cumulative dose of 50 J cm(-2) which was equivalent to irradiation of the face during indoor work for 1.5 years; and high-dose group with 1000 J cm(-2) cumulative dose equivalent to irradiation of the face during outdoor activities for 1 year. Specific indicators were measured before and after UVA irradiation. The findings showed that extending the low-dose UVA exposure decreased the skin moisture content and increased the transepidermal water loss as well as induced skin color changes (decreased L* value, increased M index). Furthermore, irradiated skin showed an increased thickness of cuticle and epidermis, skin edema, light color and unclear staining collagen fibers in the dermis, and elastic fiber fragmentation. In addition, MMP-1, p53 and SIRT1 expression was also increased. Long-term exposure of low-dose UVA radiation enhanced skin photoaging. The safety of the fluorescent lamp needs our attention. © 2014 The American Society of Photobiology.

Site-specific lead exposure from lead pellet ingestion in sentinel mallards

USGS Publications Warehouse

Rocke, T.E.; Brand, C.J.; Mensik, John G.

1997-01-01

We monitored lead poisoning from the ingestion of spent lead pellets in sentinel mallards (Anas platyhrynchos) at the Sacramento National Wildlife Refuge (SNWR), Willows, California for 4 years (1986-89) after the conversion to steel shot for waterfowl hunting on refuges in 1986. Sentinel mallards were held in 1.6-ha enclosures in 1 hunted (P8) and 2 non-hunted (T19 and TF) wetlands. We compared site-specific rates of lead exposure, as determined by periodic measurement of blood lead concentrations, and lead poisoning mortality between wetlands with different lead pellet densities, between seasons, and between male and female sentinels. In 1986, the estimated 2-week rate of lead exposure was significantly higher (P < 0.005) in P8 (43.8%), the wetland with the highest density of spent lead pellets (>2,000,000 pellets/ha), than in those with lower densities of lead pellets, T19 (18.1%; 173,200 pellets/ha) and TF (0.9%; 15,750 pellets/ha). The probability of mortality from lead poisoning was also significantly higher (P < 0.01) in sentinel mallards enclosed in P8 (0.25) than T19 (0) and TF (0) in 1986 and remained significantly higher (P < 0.001) during the 4-year study. Both lead exposure and the probability of lead poisoning mortality in P8 were significantly higher (P < 0.001) in the fall of 1986 (43.8%; 0.25), before hunting season, than in the spring of 1987 (21.6%; 0.04), after hunting season. We found no significant differences in the rates of lead exposure or lead poisoning mortality between male and female sentinel mallards. The results of this study demonstrate that in some locations, lead exposure and lead poisoning in waterfowl will continue to occur despite the conversion to steel shot for waterfowl hunting.

A mixture of Iprodione and Vinclozolin delays the onset of puberty in the male rat in a cumulative manner.

EPA Science Inventory

Vinclozolin and iprodione are dicarboximide fungicides that display anti-androgenic effects in the male rat, which suggests co-exposure to these fungicides would lead to cumulative effects on androgen-sensitive endpoints. In order to test for cumulative effects by iprodione and v...

Cumulative Risk Exposure and Mental Health Symptoms among Maltreated Youths Placed in Out-of-Home Care

PubMed Central

Raviv, Tali; Taussig, Heather N.; Culhane, Sara E.; Garrido, Edward F.

2010-01-01

Maltreated children placed in out-of-home care are at high risk for exhibiting symptoms of psychopathology by virtue of their exposure to numerous risk factors. Research examining cumulative risk has consistently found that the accumulation of risk factors increases the likelihood of mental health problems. The goal of the current study was to elucidate the relation between cumulative risk and mental health symptomatology within a sample of 252 maltreated youths (aged 9–11) placed in out-of-home care. Results confirmed the high-risk nature of this sample and identified seven salient risk variables. The cumulative risk index comprised of these seven indicators was a strong predictor of mental health symptoms, differentiating between children who scored in the clinical range with regard to mental health symptoms and those who did not. Finally, the data supported a linear model in which each incremental increase in cumulative risk was accompanied by an increase in mental health problems. This is the first known study to examine cumulative risk within a sample of youths in out-of-home care. PMID:20932576

Cumulative dietary exposure to a selected group of pesticides of the triazole group in different European countries according to the EFSA guidance on probabilistic modelling.

PubMed

Boon, Polly E; van Donkersgoed, Gerda; Christodoulou, Despo; Crépet, Amélie; D'Addezio, Laura; Desvignes, Virginie; Ericsson, Bengt-Göran; Galimberti, Francesco; Ioannou-Kakouri, Eleni; Jensen, Bodil Hamborg; Rehurkova, Irena; Rety, Josselin; Ruprich, Jiri; Sand, Salomon; Stephenson, Claire; Strömberg, Anita; Turrini, Aida; van der Voet, Hilko; Ziegler, Popi; Hamey, Paul; van Klaveren, Jacob D

2015-05-01

The practicality was examined of performing a cumulative dietary exposure assessment according to the requirements of the EFSA guidance on probabilistic modelling. For this the acute and chronic cumulative exposure to triazole pesticides was estimated using national food consumption and monitoring data of eight European countries. Both the acute and chronic cumulative dietary exposures were calculated according to two model runs (optimistic and pessimistic) as recommended in the EFSA guidance. The exposures obtained with these model runs differed substantially for all countries, with the highest exposures obtained with the pessimistic model run. In this model run, animal commodities including cattle milk and different meat types, entered in the exposure calculations at the level of the maximum residue limit (MRL), contributed most to the exposure. We conclude that application of the optimistic model run on a routine basis for cumulative assessments is feasible. The pessimistic model run is laborious and the exposure results could be too far from reality. More experience with this approach is needed to stimulate the discussion of the feasibility of all the requirements, especially the inclusion of MRLs of animal commodities which seem to result in unrealistic conclusions regarding their contribution to the dietary exposure. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cumulative exposure to shift work and sickness absence: associations in a five-year historic cohort.

PubMed

van Drongelen, Alwin; Boot, Cécile R L; Hlobil, Hynek; van der Beek, Allard J; Smid, Tjabe

2017-01-11

Exposure to shift work has been associated with negative health consequences, although the association between shift work and sickness absence remains unclear. The aim of this study is to investigate associations between cumulative exposure to shift work and sickness absence among ground staff employees of an airline company. This study used data from the MORE (Monitoring Occupational Health Risks in Employees) cohort, which is a 5-year historic cohort. The population of the present study consisted of 7562 ground staff employees. For each employee, work schedules and sickness absence days between 2005 and 2009 were obtained from company records. For the exposure to different shift schedule types and to the cumulative number of night shifts, the association with long-term sickness absence (>7 consecutive sickness absence days) and the number of sickness absence episodes during 2009, was calculated using logistic and Poisson regression analyses. Socio-demographic variables, work-related variables, job classification variables, and previous sickness absence days were regarded as confounders. After adjusting for previous sickness absence and job classification variables, only the group of employees that switched into working in a three-shift schedule, showed a significantly increased risk for long-term sickness absence (OR = 1.31, 95%CI 1.02-1.69). Night shift exposure was not significantly associated with long-term sickness absence. Exposure to shift work was negatively associated with more sickness absence episodes. Employees who were exposed to more than 46 night shifts also showed a lower risk for more sickness absence episodes. Subgroup analyses showed that single employees and employees without children had an increased risk for long-term sickness absence when exposed to a three-shift schedule, and when they had changed between shift schedule types. Cumulative exposure to shift work proved to be negatively associated with more sickness absence episodes, and

Radiation dose from common radiological investigations and cumulative exposure in children with cystic fibrosis: an observational study from a single UK centre

PubMed Central

Ward, Rebecca; Carroll, William D; Cunningham, Paula; Ho, Sheng-Ang; Jones, Mary; Lenney, Warren; Thompson, David

2017-01-01

Objectives Cumulative radiation exposure is associated with increased risk of malignancy. This is important in cystic fibrosis (CF) as frequent imaging is required to monitor disease progression and diagnose complications. Previous estimates of cumulative radiation are outdated as the imaging was performed on older equipment likely to deliver higher radiation. Our objectives were to determine the radiation dose delivered to children during common radiological investigations using modern equipment and to identify the number of such investigations performed in a cohort of children with CF to calculate their cumulative radiation exposure. Design, setting and participants Data including age at investigation and radiation exposure measured as estimated effective dose (EED) were collected on 2827 radiological studies performed on children at one UK paediatric centre. These were combined with the details of all radiological investigations performed on 65 children with CF attending the same centre to enable calculation of each child’s cumulative radiation exposure. Results The mean EED for the common radiological investigations varied according to age. The range was 0.01–0.02 mSv for chest X-rays, 0.03–0.11 mSv for abdominal X-rays, 0.57–1.69 mSv for CT chest, 2.9–3.9 mSv for abdominal and pelvic CT, 0.20–0.21 mSv for sinus CT and 0.15–0.52 mSv for fluoroscopy-guided procedures. The mean EED was three to five times higher for helical compared with axial chest CT scans. The mean annual cumulative EED for our cohort of children with CF was 0.15 mSv/year with an estimated cumulative paediatric lifetime EED (0–18 years) of 3.5 mSv. Conclusions This study provides up-to-date estimations of the radiation exposure when using common radiological investigations. These doses and the estimates of cumulative radiation exposure in children with CF are lower than previously reported. This reflects the reduced EED associated with modern equipment and the

Modeling Joint Exposures and Health Outcomes for Cumulative Risk Assessment: the Case of Radon and Smoking

EPA Science Inventory

Community-based cumulative risk assessment requires characterization of exposures to multiple chemical and non-chemical stressors, with consideration of how the non-chemical stressors may influence risks from chemical stressors. Residential radon provides an interesting case exam...

Associations of cumulative Pb exposure and longitudinal changes in Mini-Mental Status Exam scores, global cognition and domains of cognition: The VA Normative Aging Study.

PubMed

Farooqui, Zishaan; Bakulski, Kelly M; Power, Melinda C; Weisskopf, Marc G; Sparrow, David; Spiro, Avron; Vokonas, Pantel S; Nie, Linda H; Hu, Howard; Park, Sung Kyun

2017-01-01

Lead (Pb) exposure has been associated with poorer cognitive function cross-sectionally in aging adults, however the association between cumulative Pb exposure and longitudinal changes in cognition is little characterized. In a 1993-2007 subcohort of the VA Normative Aging Study (Mini-mental status exam (MMSE) n=741; global cognition summary score n=715), we used linear mixed effects models to test associations between cumulative Pb exposure (patella or tibia bone Pb) and repeated measures of cognition (MMSE, individual cognitive tests, and global cognition summary). Cox proportional hazard modeling assessed the risk of an MMSE score falling below 25. Among men 51-98 at baseline, higher patella Pb concentration (IQR: 21μg/g) was associated with -0.13 lower baseline MMSE (95% CI: -0.25, -0.004) and faster longitudinal MMSE decline (-0.016 units/year, 95% CI: -0.032, -0.0004) over 15 years. Each IQR increase in patella Pb was associated with increased risk of a MMSE score below 25 (HR=1.21, 95% CI: 0.99, 1.49; p=0.07). There were no significant associations between Pb and global cognition (both baseline and longitudinal change). Patella Pb was associated with faster longitudinal decline in Word List Total Recall in the language domain (0.014 units/year, 95% CI: -0.026, -0.001) and Word List Delayed Recall in the memory domain (0.014 units/year, 95% CI: -0.027, -0.002). We found weaker associations with tibia Pb. Cumulative Pb exposure is associated with faster declines in MMSE and Word List Total and Delayed Recall tests. These findings support the hypothesis that Pb exposure accelerates cognitive aging. Copyright © 2016 Elsevier Inc. All rights reserved.

Associations of cumulative Pb exposure and longitudinal changes in Mini-Mental Status Exam scores, global cognition and domains of cognition: The VA Normative Aging Study

PubMed Central

Farooqui, Zishaan; Bakulski, Kelly M.; Power, Melinda C.; Weisskopf, Marc G.; Sparrow, David; Spiro, Avron; Vokonas, Pantel S.; Nie, Huiling; Hu, Howard; Park, Sung Kyun

2016-01-01

Background Lead (Pb) exposure has been associated with poorer cognitive function cross-sectionally in aging adults, however the association between cumulative Pb exposure and longitudinal changes in cognition is little characterized. Methods In a 1993–2007 subcohort of the VA Normative Aging Study (Mini-mental status exam (MMSE) n=741; global cognition summary score n=715), we used linear mixed effects models to test associations between cumulative Pb exposure (patella or tibia bone Pb) and repeated measures of cognition (MMSE, individual cognitive tests, and global cognition summary). Cox proportional hazard modeling assessed the risk of an MMSE score falling below 25. Results Among men 51–98 at baseline, higher patella Pb concentration (IQR: 21 µg/g) was associated with −0.13 lower baseline MMSE (95% CI: −0.25, −0.004) and faster longitudinal MMSE decline (−0.016 units/year, 95% CI: −0.032, −0.0004) over 15 years. Each IQR increase in patella Pb was associated with increased risk of a MMSE score below 25 (HR=1.21, 95% CI: 0.99, 1.49; p=0.07). There were no significant associations between Pb and global cognition (both baseline and longitudinal change). Patella Pb was associated with faster longitudinal decline in Word List Total Recall in the language domain (0.014 units/year, 95% CI: −0.026, −0.001) and Word List Delayed Recall in the memory domain (0.014 units/year, 95% CI: −0.027, −0.002). We found weaker associations with tibia Pb. Conclusions Cumulative Pb exposure is associated with faster declines in MMSE and Word List Total and Delayed Recall tests. These findings support the hypothesis that Pb exposure accelerates cognitive aging. PMID:27770710

Cumulative Exposure Assessment for Trace-Level Polycyclic Aromatic Hydrocarbons (PAHs) using Human Blood and Plasma Analysis

EPA Science Inventory

Humans experience chronic cumulative trace-level exposure to mixtures of volatile, semi-volatile, and non-volatile polycyclic aromatic hydrocarbons (PAHs) present in the environment as by-products of combustion processes. Certain PAHs are known or suspected human carcinogens and ...

Health risks of children's cumulative and aggregative exposure to metals and metalloids in a typical urban environment in China.

PubMed

Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Chen, Yiting; Wang, Beibei; Sun, Chengye; Zheng, Binghui; Wei, Fusheng

2016-03-01

Rapid development of industrialization and urbanization results in serious environmental contamination by metal(loid)s, which would consequently cause deleterious health effects to the exposed people through multi-pathways. Therefore, total health risk assessment for the population in urban environment is very important. Unfortunately, few studies to date investigate the cumulative health risks of metal(loid)s through aggregative pathways in Children who are often susceptible population. 12 metal(loid)s including Lead(Pb), Cadmium(Cd), Arsenic(As), Chromium(Cr), Zinc(Zn), Copper(Cu), Nickel(Ni), Manganese(Mn), Cobalt(Co), Selenium(Se), Antimony(Se) and Vanadium(V), were analyzed in PM10, drinking water, food, soil and indoor dust in this study. The cumulative and aggregative risks of these metal(loid)s among the local children were then evaluated on a field sampling and questionnaire-survey basis. The results showed that the environments were heavily polluted by metal(loid)s. For most metal(loid)s, food ingestion accounted for more than 80% of the total daily exposure dose. The non-cancer risks were up to 30 times higher than the acceptable level due to the food ingestion via Pb, Cr, Cu, Zn, As, Se, Cd and Sb, and the PM10 inhalation via Cr and Mn. While, the cancer risks were mainly attributed to Cr via food ingestion and As via food and dust ingestion, and approximately 100 times of the maximum acceptable level of 1.0 × 10(-4). The study highlights the cumulative and aggregative exposure assessment, instead of pollutant investigation to evaluate the potential health risks and emphasizes concerns to improve indoor hygienic and environmental quality and to decrease the potential harmful health effects of children living in urban area. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Cumulating Exposure to Abacavir on the Risk of Cardiovascular Disease Events in Patients From the Swiss HIV Cohort Study.

PubMed

Young, Jim; Xiao, Yongling; Moodie, Erica E M; Abrahamowicz, Michal; Klein, Marina B; Bernasconi, Enos; Schmid, Patrick; Calmy, Alexandra; Cavassini, Matthias; Cusini, Alexia; Weber, Rainer; Bucher, Heiner C

2015-08-01

Patients with HIV exposed to the antiretroviral drug abacavir may have an increased risk of cardiovascular disease (CVD). There is concern that this association arises because of a channeling bias. Even if exposure is a risk, it is not clear how that risk changes as exposure cumulates. We assess the effect of exposure to abacavir on the risk of CVD events in the Swiss HIV Cohort Study. We use a new marginal structural Cox model to estimate the effect of abacavir as a flexible function of past exposures while accounting for risk factors that potentially lie on a causal pathway between exposure to abacavir and CVD. A total of 11,856 patients were followed for a median of 6.6 years; 365 patients had a CVD event (4.6 events per 1000 patient-years). In a conventional Cox model, recent--but not cumulative--exposure to abacavir increased the risk of a CVD event. In the new marginal structural Cox model, continued exposure to abacavir during the past 4 years increased the risk of a CVD event (hazard ratio = 2.06; 95% confidence interval: 1.43 to 2.98). The estimated function for the effect of past exposures suggests that exposure during the past 6-36 months caused the greatest increase in risk. Abacavir increases the risk of a CVD event: the effect of exposure is not immediate, rather the risk increases as exposure cumulates over the past few years. This gradual increase in risk is not consistent with a rapidly acting mechanism, such as acute inflammation.

Lead exposures in the human environment. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elias, R.W.

Humans consume lead by inhaling air, drinking beverages, eating food and ingesting dust. The natural source of this lead is primarily soil. Anthropogenic sources are lead in gasoline, fossil fuels and industrial products and processes. Lead is ubiquitous in the human environment, and pinpointing the primary sources of lead in any particular environmental component is difficult. Nevertheless, our purpose is to describe the total exposure of humans to environmental lead and to determine the sources of lead contributing to this exposure. The total exposure is the total amount of lead consumed by ingestion and inhalation. Excluding lead exposure from choicemore » or circumstance, a baseline level of potential human exposure can be defined for a normal individual eating a typical diet and living in a non-urban community remote from industrial sources of lead in a house without lead-based paints. Beyond this level, additive exposure factors can be determined for other environments (e.g. urban, occupational and smelter communities) and for certain habits and activities (e.g. pica, smoking, drinking and hobbies), with variation for age, sex or socioeconomic status.« less

Prenatal lead exposure and bone growth. Doctoral thesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamilton, J.D.; O'Flaherty, E.J.

1990-07-24

An experimental system of lead (7439921) related prenatal and postnatal growth retardation in rats was developed. Sprague-Dawley-rats and Long-Evans-rats were used in these studies. Rats were exposed to lead in their drinking water at up to 1000 parts per million. A significant effect on fetal bone mineralization could not be excluded and there was a definite effect on fetal body weight following maternal lead exposure. Reduced food intake during the first week of lead exposure was the primary determinant of reduced body and skeletal growth in the lead exposed weanling female rats. When maternal lead exposure was continued during lactationmore » a greater degree of lead related growth retardation in rat offspring occurred than when maternal lead exposure was terminated at parturition. Combined prenatal and postnatal lead exposure impaired bone resorption and increased growth plate widths. In studies using matrix induced endochondral bone plaques, locally applied lead enhanced plaque mineralization through comineralization of lead with calcium. When lead was administered in drinking water, plaque mineralization was also enhanced through the comineralization of lead with calcium.« less

Cumulative Risk Assessment: An Overview of Methodological Approaches for Evaluating Combined Health Effects from Exposure to Multiple Environmental Stressors

PubMed Central

Sexton, Ken

2012-01-01

Systematic evaluation of cumulative health risks from the combined effects of multiple environmental stressors is becoming a vital component of risk-based decisions aimed at protecting human populations and communities. This article briefly examines the historical development of cumulative risk assessment as an analytical tool, and discusses current approaches for evaluating cumulative health effects from exposure to both chemical mixtures and combinations of chemical and nonchemical stressors. A comparison of stressor-based and effects-based assessment methods is presented, and the potential value of focusing on viable risk management options to limit the scope of cumulative evaluations is discussed. The ultimate goal of cumulative risk assessment is to provide answers to decision-relevant questions based on organized scientific analysis; even if the answers, at least for the time being, are inexact and uncertain. PMID:22470298

Recommendations for Medical Management of Adult Lead Exposure

PubMed Central

Kosnett, Michael J.; Wedeen, Richard P.; Rothenberg, Stephen J.; Hipkins, Karen L.; Materna, Barbara L.; Schwartz, Brian S.; Hu, Howard; Woolf, Alan

2007-01-01

Research conducted in recent years has increased public health concern about the toxicity of lead at low dose and has supported a reappraisal of the levels of lead exposure that may be safely tolerated in the workplace. In this article, which appears as part of a mini-monograph on adult lead exposure, we summarize a body of published literature that establishes the potential for hypertension, effects on renal function, cognitive dysfunction, and adverse female reproductive outcome in adults with whole-blood lead concentrations < 40 μg/dL. Based on this literature, and our collective experience in evaluating lead-exposed adults, we recommend that individuals be removed from occupational lead exposure if a single blood lead concentration exceeds 30 μg/dL or if two successive blood lead concentrations measured over a 4-week interval are ≥ 20 μg/dL. Removal of individuals from lead exposure should be considered to avoid long-term risk to health if exposure control measures over an extended period do not decrease blood lead concentrations to < 10 μg/dL or if selected medical conditions exist that would increase the risk of continued exposure. Recommended medical surveillance for all lead-exposed workers should include quarterly blood lead measurements for individuals with blood lead concentrations between 10 and 19 μg/dL, and semiannual blood lead measurements when sustained blood lead concentrations are < 10 μg/dL. It is advisable for pregnant women to avoid occupational or avocational lead exposure that would result in blood lead concentrations > 5 μg/dL. Chelation may have an adjunctive role in the medical management of highly exposed adults with symptomatic lead intoxication but is not recommended for asymptomatic individuals with low blood lead concentrations. PMID:17431500

Lead Exposure Hazard Management Guide

DTIC Science & Technology

1993-12-01

that may pose chemical or physical problems . Make this section specific to your base or location. b. Exposure Routes. The potential routes of...Pregnant Mother ........ 14 nstallatio (Base) Lead Te xicity Investigations . Team Makeup and Duties ............ 15 Lead Toxicity Investigation...occurring in tradesmen who used lead in their occupations. The favorable physical and chemical properties of lead accounted for its extensive use. Lead can

Children’s Phthalate Intakes and Resultant Cumulative Exposures Estimated from Urine Compared with Estimates from Dust Ingestion, Inhalation and Dermal Absorption in Their Homes and Daycare Centers

PubMed Central

Bekö, Gabriel; Weschler, Charles J.; Langer, Sarka; Callesen, Michael; Toftum, Jørn; Clausen, Geo

2013-01-01

Total daily intakes of diethyl phthalate (DEP), di(n-butyl) phthalate (DnBP), di(isobutyl) phthalate (DiBP), butyl benzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) were calculated from phthalate metabolite levels measured in the urine of 431 Danish children between 3 and 6 years of age. For each child the intake attributable to exposures in the indoor environment via dust ingestion, inhalation and dermal absorption were estimated from the phthalate levels in the dust collected from the child’s home and daycare center. Based on the urine samples, DEHP had the highest total daily intake (median: 4.42 µg/d/kg-bw) and BBzP the lowest (median: 0.49 µg/d/kg-bw). For DEP, DnBP and DiBP, exposures to air and dust in the indoor environment accounted for approximately 100%, 15% and 50% of the total intake, respectively, with dermal absorption from the gas-phase being the major exposure pathway. More than 90% of the total intake of BBzP and DEHP came from sources other than indoor air and dust. Daily intake of DnBP and DiBP from all exposure pathways, based on levels of metabolites in urine samples, exceeded the Tolerable Daily Intake (TDI) for 22 and 23 children, respectively. Indoor exposures resulted in an average daily DiBP intake that exceeded the TDI for 14 children. Using the concept of relative cumulative Tolerable Daily Intake (TDIcum), which is applicable for phthalates that have established TDIs based on the same health endpoint, we examined the cumulative total exposure to DnBP, DiBP and DEHP from all pathways; it exceeded the tolerable levels for 30% of the children. From the three indoor pathways alone, several children had a cumulative intake that exceeded TDIcum. Exposures to phthalates present in the air and dust indoors meaningfully contribute to a child’s total intake of certain phthalates. Such exposures, by themselves, may lead to intakes exceeding current limit values. PMID:23626820

Determinants of bone and blood lead concentrations in the early postpartum period

PubMed Central

Brown, M. J.; Hu, H.; Gonzales-Cossio, T.; Peterson, K.; Sanin, L.; Kageyama, M. d.; Palazuelos, E.; Aro, A.; Schnaas, L.; Hernandez-Avila, M.

2000-01-01

OBJECTIVE—This study investigated determinants of bone and blood lead concentrations in 430 lactating Mexican women during the early postpartum period and the contribution of bone lead to blood lead.
METHODS—Maternal venous lead was measured at delivery and postpartum, and bone lead concentrations, measured with in vivo K-x ray fluorescence, were measured post partum. Data on environmental exposure, demographic characteristics, and maternal factors related to exposure to lead were collected by questionnaire. Linear regression was used to examine the relations between bone and blood lead, demographics, and environmental exposure variables.
RESULTS—Mean (SD) blood, tibial, and patellar lead concentrations were 9.5 (4.5) µg/dl, 10.2 (10.1) µg Pb/g bone mineral, and 15.2 (15.1) µg Pb/g bone mineral respectively. These values are considerably higher than values for women in the United States. Older age, the cumulative use of lead glazed pottery, and higher proportion of life spent in Mexico City were powerful predictors of higher bone lead concentrations. Use of lead glazed ceramics to cook food in the past week and increased patellar lead concentrations were significant predictors of increased blood lead. Patellar lead concentrations explained one third of the variance accounted for by the final blood lead model. Women in the 90th percentile for patella lead had an untransformed predicted mean blood lead concentration 3.6 µg/dl higher than those in the 10th percentile.
CONCLUSIONS—This study identified the use of lead glazed ceramics as a major source of cumulative exposure to lead, as reflected by bone lead concentrations, as well as current exposure, reflected by blood lead, in Mexico. A higher proportion of life spent in Mexico City, a proxy for exposure to leaded gasoline emissions, was identified as the other major source of cumulative lead exposure. The influence of bone lead on blood lead coupled with the long half life of lead in bone has

Lead remediation and changes in human lead exposure: some physiological and biokinetic dimensions.

PubMed

Mushak, Paul

2003-02-15

This paper presents a qualitative and quantitative analysis of the various aspects of lead remediation effectiveness with particular reference to human health risk assessment. One of the key elements of lead remediation efforts at such sites as those under the Superfund program deals with populations at elevated exposure and toxicity risk in the proximity of, or at, the site of remediation, especially remediation workers, workers at other tasks on sites that were remediated down to some action level of lead concentration in soils, and groups at risk in nearby communities. A second element has to do with how one measures or models lead exposure changes with special reference to baseline and post-remediation conditions. Various biomarkers of lead exposure can be employed, but their use requires detailed knowledge of what results using each means. The most commonly used approach is measurement of blood lead (Pb-B). Recognized limitations in the use of Pb-B has led to the use of predictive Pb exposure models, which are less vulnerable to the many behavioral, physiological, and environmental parameters that can distort isolated or 'single shot' Pb-B testings. A third aspect covered in this paper presents various physiological factors that affect the methods by which one evaluates Pb remediation effectiveness. Finally, this article offers an integrated look at how lead remediation actions directed at one lead source or pathway affect the total lead exposure picture for human populations at elevated lead exposure and toxicity risk.

Assessment of Lead Exposure Risk in Locksmiths

PubMed Central

Kondrashov, Vladislav; McQuirter, Joseph L.; Miller, Melba; Rothenberg, Stephen J.

2005-01-01

Exposure to lead has been well recognized in a number of work environments, but little is known about lead exposure associated with machining brass keys containing lead. The brass that is widely used for key manufacturing usually contains 1.5% – 2.5 % of lead. Six (6) licensed locksmiths and 6 case-matched controls successfully completed the pilot study to assess the prevalence of increased body lead burden of professional locksmiths. We measured both Blood Lead (atomic absorption spectrometry), bone-lead (KXRF) and had each subject complete a health and lead exposure risk questionnaire. One locksmith had not cut keys during the past two years, therefore this subject and case-matched control was excluded from the blood lead analysis only. The average blood-lead concentration (±SEM) for the 5 paired subjects was 3.1 (± 0.4) μg/dL and 2.2 (± 0.3) μg /dL for controls. Bone measurements, including all 6 paired subjects, showed tibia lead concentration (±SEM) for locksmiths and controls was 27.8 (± 2.3) μg /g and 13.7 (± 3.3) μg /g, respectively; average calcaneus lead concentration for locksmiths and controls was 31.9 (± 3.7) μg /g and 22.6 (± 4.1) μg /g, respectively: The t-test shows a significantly higher tibia lead (p<0.05) and blood lead (p<0.05) for locksmiths than for their matched controls, but no significant difference for calcaneus lead (p>0.10). Given that the mean tibia bone lead concentration was 13.1μg/g higher in locksmiths than in their matched controls, this average difference in the two groups would translate to an OR of increased hypertension in locksmiths of between 1.1 and 2.3, based on the published literature. Even with the very small number of subjects participating in this pilot study, we were able to demonstrate that locksmiths had significantly higher current exposure to lead (blood lead concentration) and significantly higher past exposure to lead (tibia lead concentration) than their age, sex and ethnically matched controls

Examining cumulative victimization, community violence exposure, and stigma as contributors to PTSD symptoms among high-risk young women.

PubMed

Kennedy, Angie C; Bybee, Deborah; Greeson, Megan R

2014-05-01

This study examines patterns of lifetime victimization within the family, community violence exposure, and stigma as contributors to posttraumatic stress disorder (PTSD) symptoms within a sample of 198 high-risk young women who are pregnant or parenting. We used cluster analysis to identify 5 profiles of cumulative victimization, based on participants' levels of witnessing intimate partner violence (IPV), physical abuse by an adult caregiver, and sexual victimization, all beginning by age 12. Hierarchical regression was used to examine these 5 clusters (ranging from a High All Victimization cluster characterized by high levels of all 3 forms of violence, to a Low All Victimization cluster characterized by low levels of all 3 forms), along with community violence exposure and stigma, as predictors of PTSD symptoms. We found that 3 of the cumulative victimization clusters, in comparison with Low All Victimization, were significant predictors of PTSD symptoms, as was stigma, while community violence exposure was not a significant predictor. PsycINFO Database Record (c) 2014 APA, all rights reserved

Cumulative exposure to medical sources of ionizing radiation in the first year after pediatric heart transplantation.

PubMed

McDonnell, Alicia; Downing, Tacy E; Zhu, Xiaowei; Ryan, Rachel; Rossano, Joseph W; Glatz, Andrew C

2014-11-01

Pediatric heart transplant recipients undergo a variety of radiologic tests with the attendant risk of exposure to ionizing radiation. We sought to quantify and describe the cumulative exposure to all forms of medical radiation during the first year after pediatric heart transplantation and identify factors associated with higher exposure. Pediatric patients who received a heart transplant between January 2009 and May 2012 with follow-up at our institution were retrospectively reviewed. Patients were included if they survived through 1 year and the first coronary angiography. All medical testing using ionizing radiation performed during follow-up was compiled, and exposures were converted to effective dose (mSv). Included were 31 patients who underwent heart transplantation at a median age of 13.6 years (range, 0.3-18.3 years). The median number of radiologic tests performed was 38 (range, 18-154), including 8 catheterizations (range, 2-12), and 28 X-ray images (range, 11-135). Median cumulative effective dose was 53.5 mSv (range, 10.6-153.5 mSv), of which 91% (range, 34%-98%) derived from catheterizations, 31% (range, 8%-89%) of the exposure occurred during the transplant admission, 59% (range, 11%-88%) during planned follow-up, and 3% (0%-56%) during unplanned follow-up. Older age at transplant was a risk factor for increased exposure (p = 0.006). When adjusted for age, a trend toward increased exposure was shown for congenital heart disease as the indication for transplant (p = 0.08), pre-sensitization (p = 0.12), and positive crossmatch (p = 0.09). Pediatric heart transplant patients are exposed to significant amounts of ionizing radiation during the first post-transplant year, most during scheduled catheterization. As survival improves, considering the long-term risks associated with these levels of exposure is important. Copyright © 2014 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Using exposomics to assess cumulative risks and promote health.

PubMed

Smith, Martyn T; de la Rosa, Rosemarie; Daniels, Sarah I

2015-12-01

Under the exposome paradigm all nongenetic factors contributing to disease are considered to be 'environmental' including chemicals, drugs, infectious agents, and psychosocial stress. We can consider these collectively as environmental stressors. Exposomics is the comprehensive analysis of exposure to all environmental stressors and should yield a more thorough understanding of chronic disease development. We can operationalize exposomics by studying all the small molecules in the body and their influence on biological pathways that lead to impaired health. Here, we describe methods by which this may be achieved and discuss the application of exposomics to cumulative risk assessment in vulnerable populations. Since the goal of cumulative risk assessment is to analyze, characterize, and quantify the combined risks to health from exposures to multiple agents or stressors, it seems that exposomics is perfectly poised to advance this important area of environmental health science. We should therefore support development of tools for exposomic analysis and begin to engage impacted communities in participatory exposome research. A first step may be to apply exposomics to vulnerable populations already studied by more conventional cumulative risk approaches. We further propose that recent migrants, low socioeconomic groups with high environmental chemical exposures, and pregnant women should be high priority populations for study by exposomics. Moreover, exposomics allows us to study interactions between chronic stress and environmental chemicals that disrupt stress response pathways (i.e., 'stressogens'). Exploring the impact of early life exposures and maternal stress may be an interesting and accessible topic for investigation by exposomics using biobanked samples. © 2015 Wiley Periodicals, Inc.

Measuring women's cumulative neighborhood deprivation exposure using longitudinally linked vital records: a method for life course MCH research.

PubMed

Kramer, Michael R; Dunlop, Anne L; Hogue, Carol J R

2014-02-01

A life course conceptual framework for MCH research demands new tools for understanding population health and measuring exposures. We propose a method for measuring population-based socio-environmental trajectories for women of reproductive age. We merged maternal longitudinally-linked births to Georgia-resident women from 1994 to 2007 with census economic and social measures using residential geocodes to create woman-centered socio-environmental trajectories. We calculated a woman's neighborhood deprivation index (NDI) at the time of each of her births and, from these, we calculated a cumulative NDI. We fit Loess curves to describe average life course NDI trajectories and binomial regression models to test specific life course theory hypotheses relating cumulative NDI to risk for preterm birth. Of the 1,815,944 total live births, we linked 1,000,437 live births to 413,048 unique women with two or more births. Record linkage had high specificity but relatively low sensitivity which appears non-differential with respect to maternal characteristics. Georgia women on average experienced upward mobility across the life course, although differences by race, early life neighborhood quality, and age at first birth produced differences in cumulative NDI. Adjusted binomial models found evidence for modification of the effect of history of prior preterm birth and advancing age on risk for preterm birth by cumulative NDI. The creation of trajectories from geocoded maternal longitudinally-linked vital records is one method to carry out life course MCH research. We discuss approaches for investigating the impact of truncation of the life course, selection bias from migration, and misclassification of cumulative exposure.

Lead Exposure during Early Human Development and DNA Methylation of Imprinted Gene Regulatory Elements in Adulthood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yue; Xie, Changchun; Murphy, Susan K.

Here, lead exposure during early development causes neurodevelopmental disorders by unknown mechanisms. Epidemiologic studies have focused recently on determining associations between lead exposure and global DNA methylation; however, such approaches preclude the identification of loci that may alter human disease risk. The objective of this study was to determine whether maternal, postnatal, and early childhood lead exposure can alter the differentially methylated regions (DMRs) that control the monoallelic expression of imprinted genes involved in metabolism, growth, and development. Questionnaire data and serial blood lead levels were obtained from 105 participants (64 females, 41 males) of the Cincinnati Lead Study frommore » birth to 78 months. When participants were adults, we used Sequenom EpiTYPER assays to test peripheral blood DNA to quantify CpG methylation in peripheral blood leukocytes at DMRs of 22 human imprinted genes. Statistical analyses were conducted using linear regression. Mean blood lead concentration from birth to 78 months was associated with a significant decrease in PEG3 DMR methylation (β = –0.0014; 95% CI: –0.0023, –0.0005, p = 0.002), stronger in males (β = –0.0024; 95% CI: –0.0038, –0.0009, p = 0.003) than in females (β = –0.0009; 95% CI: –0.0020, 0.0003, p = 0.1). Elevated mean childhood blood lead concentration was also associated with a significant decrease in IGF2/H19 (β = –0.0013; 95% CI: –0.0023, –0.0003, p = 0.01) DMR methylation, but primarily in females, (β = –0.0017; 95% CI: –0.0029, –0.0006, p = 0.005) rather than in males, (β = –0.0004; 95% CI: –0.0023, 0.0015, p = 0.7). Elevated blood lead concentration during the neonatal period was associated with higher PLAGL1/HYMAI DMR methylation regardless of sex (β = 0.0075; 95% CI: 0.0018, 0.0132, p = 0.01). The magnitude of associations between cumulative lead exposure and CpG methylation remained unaltered from 30 to 78 months. Our

Lead Exposure during Early Human Development and DNA Methylation of Imprinted Gene Regulatory Elements in Adulthood

DOE PAGES

Li, Yue; Xie, Changchun; Murphy, Susan K.; ...

2015-06-26

Here, lead exposure during early development causes neurodevelopmental disorders by unknown mechanisms. Epidemiologic studies have focused recently on determining associations between lead exposure and global DNA methylation; however, such approaches preclude the identification of loci that may alter human disease risk. The objective of this study was to determine whether maternal, postnatal, and early childhood lead exposure can alter the differentially methylated regions (DMRs) that control the monoallelic expression of imprinted genes involved in metabolism, growth, and development. Questionnaire data and serial blood lead levels were obtained from 105 participants (64 females, 41 males) of the Cincinnati Lead Study frommore » birth to 78 months. When participants were adults, we used Sequenom EpiTYPER assays to test peripheral blood DNA to quantify CpG methylation in peripheral blood leukocytes at DMRs of 22 human imprinted genes. Statistical analyses were conducted using linear regression. Mean blood lead concentration from birth to 78 months was associated with a significant decrease in PEG3 DMR methylation (β = –0.0014; 95% CI: –0.0023, –0.0005, p = 0.002), stronger in males (β = –0.0024; 95% CI: –0.0038, –0.0009, p = 0.003) than in females (β = –0.0009; 95% CI: –0.0020, 0.0003, p = 0.1). Elevated mean childhood blood lead concentration was also associated with a significant decrease in IGF2/H19 (β = –0.0013; 95% CI: –0.0023, –0.0003, p = 0.01) DMR methylation, but primarily in females, (β = –0.0017; 95% CI: –0.0029, –0.0006, p = 0.005) rather than in males, (β = –0.0004; 95% CI: –0.0023, 0.0015, p = 0.7). Elevated blood lead concentration during the neonatal period was associated with higher PLAGL1/HYMAI DMR methylation regardless of sex (β = 0.0075; 95% CI: 0.0018, 0.0132, p = 0.01). The magnitude of associations between cumulative lead exposure and CpG methylation remained unaltered from 30 to 78 months. Our

Occupational lead exposure aboard a tall ship.

PubMed

Landrigan, P J; Straub, W E

1985-01-01

To evaluate occupational exposures to lead in shipfitters cutting and riveting lead-painted iron plates aboard an iron-hulled sailing vessel, we conducted an environmental and medical survey. Lead exposures in seven personal (breathing zone) air samples ranged from 108 to 500 micrograms/m3 (mean 257 micrograms/m3); all were above the Occupational Safety and Health Administration (OSHA) standard of 50 micrograms/m3. In two short-term air samples obtained while exhaust ventilation was temporarily disconnected, mean lead exposure rose to 547 micrograms/m3. Blood lead levels in ten shipfitters ranged from 25 to 53 micrograms/dl (mean, 37.8 micrograms/dl); levels in three of these workers exceeded the upper normal limit of 40 micrograms/dl. Blood lead levels in shipfitters were significantly higher than in other shipyard workers (mean 10.0 micrograms/dl; p less than 0.001). Smoking shipfitters (mean, 47 micrograms/dl) had significantly higher lead levels than nonsmokers (mean, 32 micrograms/dl; p = 0.03). Lead levels in shipfitters who wore respirators were not lower than in those who wore no protective gear (p = 0.68). Four shipfitters had erythrocyte protoporphyrin (EP) concentrations above the adult upper normal limit of 50 micrograms/dl. A close correlation was found between blood lead and EP levels (r = 0.70). Prevalence of lead-related symptoms was no higher in shipfitters than in other workers. No cases of symptomatic lead poisoning were noted. These data indicate that serious occupational exposure to lead can occur in a relatively small boatyard.

Alzheimer’s Disease and Environmental Exposure to Lead: The Epidemiologic Evidence and Potential Role of Epigenetics

PubMed Central

Bakulski, Kelly M.; Rozek, Laura S.; Dolinoy, Dana C.; Paulson, Henry L.; Hu, Howard

2013-01-01

Several lines of evidence indicate that the etiology of late-onset Alzheimer’s disease (LOAD) is complex, with significant contributions from both genes and environmental factors. Recent research suggests the importance of epigenetic mechanisms in defining the relationship between environmental exposures and LOAD. In epidemiologic studies of adults, cumulative lifetime lead (Pb) exposure has been associated with accelerated declines in cognition. In addition, research in animal models suggests a causal association between Pb exposure during early life, epigenetics, and LOAD. There are multiple challenges to human epidemiologic research evaluating the relationship between epigenetics, LOAD, and Pb exposure. Epidemiologic studies are not well-suited to accommodate the long latency period between exposures during early life and onset of Alzheimer’s disease. There is also a lack of validated circulating epigenetics biomarkers and retrospective biomarkers of Pb exposure. Members of our research group have shown bone Pb is an accurate measurement of historical Pb exposure in adults, offering an avenue for future epidemiologic studies. However, this would not address the risk of LOAD attributable to early-life Pb exposures. Future studies that use a cohort design to measure both Pb exposure and validated epigenetic biomarkers of LOAD will be useful to clarify this important relationship. PMID:22272628

Childhood Lead Exposure from Battery Recycling in Vietnam.

PubMed

Daniell, William E; Van Tung, Lo; Wallace, Ryan M; Havens, Deborah J; Karr, Catherine J; Bich Diep, Nguyen; Croteau, Gerry A; Beaudet, Nancy J; Duy Bao, Nguyen

2015-01-01

Battery recycling facilities in developing countries can cause community lead exposure. To evaluate child lead exposure in a Vietnam battery recycling craft village after efforts to shift home-based recycling outside the village. This cross-sectional study evaluated 109 children in Dong Mai village, using blood lead level (BLL) measurement, parent interview, and household observation. Blood samples were analyzed with a LeadCare II field instrument; highest BLLs (≥45 μg/dL) were retested by laboratory analysis. Surface and soil lead were measured at 11 households and a school with X-ray fluorescence analyzer. All children had high BLLs; 28% had BLL ≥45 μg/dL. Younger age, family recycling, and outside brick surfaces were associated with higher BLL. Surface and soil lead levels were high at all tested homes, even with no recycling history. Laboratory BLLs were lower than LeadCare BLLs, in 24 retested children. In spite of improvements, lead exposure was still substantial and probably associated with continued home-based recycling, legacy contamination, and workplace take-home exposure pathways. There is a need for effective strategies to manage lead exposure from battery recycling in craft villages. These reported BLL values should be interpreted cautiously, although the observed field-laboratory discordance may reflect bias in laboratory results.

Lead exposure potentiates predatory attack behavior in the cat.

PubMed

Li, Wenjie; Han, Shenggao; Gregg, Thomas R; Kemp, Francis W; Davidow, Amy L; Louria, Donald B; Siegel, Allan; Bogden, John D

2003-07-01

Epidemiologic studies have demonstrated that environmental lead exposure is associated with aggressive behavior in children; however, numerous confounding variables limit the ability of these studies to establish a causal relationship. The study of aggressive behavior using a validated animal model was used to test the hypothesis that there is a causal relationship between lead exposure and aggression in the absence of confounding variables. We studied the effects of lead exposure on a feline model of aggression: predatory (quiet biting) attack of an anesthetized rat. Five cats were stimulated with a precisely controlled electrical current via electrodes inserted into the lateral hypothalamus. The response measure was the predatory attack threshold current (i.e., the current required to elicit an attack response on 50% of the trials). Blocks of trials were administered in which predatory attack threshold currents were measured three times a week for a total of 6-10 weeks, including before, during, and after lead exposure. Lead was incorporated into cat food "treats" at doses of 50-150 mg/kg/day. Two of the five cats received a second period of lead exposure. Blood lead concentrations were measured twice a week and were <1, 21-77, and <20 micro g/dL prior to, during, and after lead exposure, respectively. The predatory attack threshold decreased significantly during initial lead exposure in three of five cats and increased after the cessation of lead exposure in four of the five cats (P<0.01). The predatory attack thresholds and blood lead concentrations for each cat were inversely correlated (r=-0.35 to -0.74). A random-effects mixed model demonstrated a significant (P=0.0019) negative association between threshold current and blood lead concentration. The data of this study demonstrate that lead exposure enhances predatory aggression in the cat and provide experimental support for a causal relationship between lead exposure and aggressive behavior in humans.

HUMAN EXPOSURE MODELING FOR CUMULATIVE RISK

EPA Science Inventory

US EPA's Office of Research and Development (ORD) has identified cumulative risk assessment as a priority research area. This is because humans and other organisms are exposed to a multitude of chemicals, physical agents, and other stressors through multiple pathways, routes, an...

Repeated exposure to high-frequency spanking and child externalizing behavior across the first decade: a moderating role for cumulative risk.

PubMed

MacKenzie, Michael J; Nicklas, Eric; Brooks-Gunn, Jeanne; Waldfogel, Jane

2014-12-01

This study used the Fragile Families and Child Well-Being Study to examine the effects of repeated exposure to harsh parenting on child externalizing behavior across the first decade of life, and a moderating role for cumulative ecological risk. Maternal report of harsh parenting, defined as high frequency spanking, was assessed at age 1, 3, 5, and 9, along with child externalizing at age 9 (N=2,768). Controlling for gender, race, maternal nativity, and city of residence, we found a cumulative risk index to significantly moderate the effects of repeated harsh parenting on child behavior, with the effects of repeated high-frequency spanking being amplified for those experiencing greater levels of cumulative risk. Harsh parenting, in the form of high frequency spanking, remains a too common experience for children, and results demonstrate that the effects of repeated exposure to harsh parenting across the first decade are amplified for those children already facing the most burden. Copyright © 2014. Published by Elsevier Ltd.

Repeated exposure to high-frequency spanking and child externalizing behavior across the first decade: A moderating role for cumulative risk

PubMed Central

MacKenzie, Michael J.; Nicklas, Eric; Brooks-Gunn, Jeanne; Waldfogel, Jane

2016-01-01

This study used the Fragile Families and Child Well-being study to examine the effects of repeated exposure to harsh parenting on child externalizing behavior across the first decade of life, and a moderating role for cumulative ecological risk. Maternal report of harsh parenting, defined as high frequency spanking, was assessed at age 1, 3, 5, and 9, along with child externalizing at age 9 (N=2768). Controlling for gender, race, maternal nativity, and city of residence, we found a cumulative risk index to significantly moderate the effects of repeated harsh parenting on child behavior, with the effects of repeated high-frequency spanking being amplified for those experiencing greater levels of cumulative risk. Harsh parenting, in the form of high frequency spanking, remains a too common experience for children, and results demonstrate that the effects of repeated exposure to harsh parenting across the first decade are amplified for those children already facing the most burden. PMID:25465318

Cumulative Risk Exposure and Mental Health Symptoms among Maltreated Youth Placed in Out-of-Home Care

ERIC Educational Resources Information Center

Raviv, Tali; Taussig, Heather N.; Culhane, Sara E.; Garrido, Edward F.

2010-01-01

Objective: Maltreated children placed in out-of-home care are at high risk for exhibiting symptoms of psychopathology by virtue of their exposure to numerous risk factors. Research examining cumulative risk has consistently found that the accumulation of risk factors increases the likelihood of mental health problems. The goal of the current study…

Associations of cumulative sun exposure and phenotypic characteristics with histologic solar elastosis

PubMed Central

Thomas, Nancy E.; Kricker, Anne; From, Lynn; Busam, Klaus; Millikan, Robert C.; Ritchey, Mary E.; Armstrong, Bruce K.; Lee-Taylor, Julia; Marrett, Loraine D.; Anton-Culver, Hoda; Zanetti, Roberto; Rosso, Stefano; Gallagher, Richard P.; Dwyer, Terence; Goumas, Chris; Kanetsky, Peter A.; Begg, Colin B.; Orlow, Irene; Wilcox, Homer; Paine, Susan; Berwick, Marianne

2010-01-01

Background Solar elastosis adjacent to melanomas in histologic sections is regarded as an indicator of sun exposure although the associations of ultraviolet (UV) exposure and phenotype with solar elastosis are yet to be fully explored. Methods The study included 2,589 incident primary melanoma patients with assessment of histologic solar elastosis in the population-based Genes, Environment, and Melanoma study. Ambient erythemal UV (UVE) at places of residence and sun exposure hours, including body site-specific exposure, were collected. We examined the association of cumulative site-specific and non site-specific sun exposure hours and ambient UVE with solar elastosis in multivariable models adjusted for age, sex, center, pigmentary characteristics, nevi and, where relevant, body site. Results Solar elastosis was associated most strongly with site-specific UVE (OR for top exposure quartile, 5.20; 95% CI, 3.40-7.96; P for trend <0.001) and also with site-specific sun exposure (OR for top quartile, 5.12; 95% CI, 3.35-7.83; P for trend <0.001). Older age (OR at >70 years, 7.69; 95% CI, 5.14-11.52); P trend < 0.001) and having more than 10 back nevi (OR, 0.77; 95% CI, 0.61-0.97; P = 0.03) were independently associated with solar elastosis. Conclusion Solar elastosis had a strong association with higher site-specific UVE dose, older age and fewer nevi. Impact Solar elastosis could be a useful biomarker of lifetime site-specific UV. Future research is needed to explore whether age represents more than simple accumulation of sun exposure and the reason that people with more nevi may be less prone to solar elastosis. PMID:20802019

Associations of cumulative sun exposure and phenotypic characteristics with histologic solar elastosis.

PubMed

Thomas, Nancy E; Kricker, Anne; From, Lynn; Busam, Klaus; Millikan, Robert C; Ritchey, Mary E; Armstrong, Bruce K; Lee-Taylor, Julia; Marrett, Loraine D; Anton-Culver, Hoda; Zanetti, Roberto; Rosso, Stefano; Gallagher, Richard P; Dwyer, Terence; Goumas, Chris; Kanetsky, Peter A; Begg, Colin B; Orlow, Irene; Wilcox, Homer; Paine, Susan; Berwick, Marianne

2010-11-01

Solar elastosis adjacent to melanomas in histologic sections is regarded as an indicator of sun exposure, although the associations of UV exposure and phenotype with solar elastosis are yet to be fully explored. The study included 2,589 incident primary melanoma patients with assessment of histologic solar elastosis in the population-based Genes, Environment, and Melanoma study. Ambient erythemal UV (UVE) at places of residence and sun exposure hours, including body site-specific exposure, were collected. We examined the association of cumulative site-specific and non-site-specific sun exposure hours and ambient UVE with solar elastosis in multivariable models adjusted for age, sex, center, pigmentary characteristics, nevi, and, where relevant, body site. Solar elastosis was associated most strongly with site-specific UVE [odds ratio (OR) for top exposure quartile, 5.20; 95% confidence interval (95% CI), 3.40-7.96; P for trend <0.001] and also with site-specific sun exposure (OR for top quartile, 5.12; 95% CI, 3.35-7.83; P for trend <0.001). Older age (OR at >70 years, 7.69; 95% CI, 5.14-11.52; P for trend < 0.001) and having more than 10 back nevi (OR, 0.77; 95% CI, 0.61-0.97; P = 0.03) were independently associated with solar elastosis. Solar elastosis had a strong association with higher site-specific UVE dose, older age, and fewer nevi. Solar elastosis could be a useful biomarker of lifetime site-specific UV. Future research is needed to explore whether age represents more than simple accumulation of sun exposure and to determine why people with more nevi may be less prone to solar elastosis. ©2010 AACR.

An analysis of cumulative risks based on biomonitoring data for six phthalates using the Maximum Cumulative Ratio

EPA Science Inventory

The Maximum Cumulative Ratio (MCR) quantifies the degree to which a single chemical drives the cumulative risk of an individual exposed to multiple chemicals. Phthalates are a class of chemicals with ubiquitous exposures in the general population that have the potential to cause ...

Childhood Lead Exposure from Battery Recycling in Vietnam

PubMed Central

Van Tung, Lo; Wallace, Ryan M.; Havens, Deborah J.; Karr, Catherine J.; Bich Diep, Nguyen; Croteau, Gerry A.; Beaudet, Nancy J.; Duy Bao, Nguyen

2015-01-01

Background. Battery recycling facilities in developing countries can cause community lead exposure. Objective. To evaluate child lead exposure in a Vietnam battery recycling craft village after efforts to shift home-based recycling outside the village. Methods. This cross-sectional study evaluated 109 children in Dong Mai village, using blood lead level (BLL) measurement, parent interview, and household observation. Blood samples were analyzed with a LeadCare II field instrument; highest BLLs (≥45 μg/dL) were retested by laboratory analysis. Surface and soil lead were measured at 11 households and a school with X-ray fluorescence analyzer. Results. All children had high BLLs; 28% had BLL ≥45 μg/dL. Younger age, family recycling, and outside brick surfaces were associated with higher BLL. Surface and soil lead levels were high at all tested homes, even with no recycling history. Laboratory BLLs were lower than LeadCare BLLs, in 24 retested children. Discussion. In spite of improvements, lead exposure was still substantial and probably associated with continued home-based recycling, legacy contamination, and workplace take-home exposure pathways. There is a need for effective strategies to manage lead exposure from battery recycling in craft villages. These reported BLL values should be interpreted cautiously, although the observed field-laboratory discordance may reflect bias in laboratory results. PMID:26587532

Cumulative Retrospective Exposure Assessment (REA) as a predictor of amphibole asbestos lung burden: validation procedures and results for industrial hygiene and pathology estimates.

PubMed

Rasmuson, James O; Roggli, Victor L; Boelter, Fred W; Rasmuson, Eric J; Redinger, Charles F

2014-01-01

A detailed evaluation of the correlation and linearity of industrial hygiene retrospective exposure assessment (REA) for cumulative asbestos exposure with asbestos lung burden analysis (LBA) has not been previously performed, but both methods are utilized for case-control and cohort studies and other applications such as setting occupational exposure limits. (a) To correlate REA with asbestos LBA for a large number of cases from varied industries and exposure scenarios; (b) to evaluate the linearity, precision, and applicability of both industrial hygiene exposure reconstruction and LBA; and (c) to demonstrate validation methods for REA. A panel of four experienced industrial hygiene raters independently estimated the cumulative asbestos exposure for 363 cases with limited exposure details in which asbestos LBA had been independently determined. LBA for asbestos bodies was performed by a pathologist by both light microscopy and scanning electron microscopy (SEM) and free asbestos fibers by SEM. Precision, reliability, correlation and linearity were evaluated via intraclass correlation, regression analysis and analysis of covariance. Plaintiff's answers to interrogatories, work history sheets, work summaries or plaintiff's discovery depositions that were obtained in court cases involving asbestos were utilized by the pathologist to provide a summarized brief asbestos exposure and work history for each of the 363 cases. Linear relationships between REA and LBA were found when adjustment was made for asbestos fiber-type exposure differences. Significant correlation between REA and LBA was found with amphibole asbestos lung burden and mixed fiber-types, but not with chrysotile. The intraclass correlation coefficients (ICC) for the precision of the industrial hygiene rater cumulative asbestos exposure estimates and the precision of repeated laboratory analysis were found to be in the excellent range. The ICC estimates were performed independent of specific asbestos

Comparative Risks of Cancer from Drywall Finishing Based on Stochastic Modeling of Cumulative Exposures to Respirable Dusts and Chrysotile Asbestos Fibers.

PubMed

Boelter, Fred W; Xia, Yulin; Dell, Linda

2015-05-01

Sanding joint compounds is a dusty activity and exposures are not well characterized. Until the mid 1970s, asbestos-containing joint compounds were used by some people such that sanding could emit dust and asbestos fibers. We estimated the distribution of 8-h TWA concentrations and cumulative exposures to respirable dusts and chrysotile asbestos fibers for four worker groups: (1) drywall specialists, (2) generalists, (3) tradespersons who are bystanders to drywall finishing, and (4) do-it-yourselfers (DIYers). Data collected through a survey of experienced contractors, direct field observations, and literature were used to develop prototypical exposure scenarios for each worker group. To these exposure scenarios, we applied a previously developed semi-empirical mathematical model that predicts area as well as personal breathing zone respirable dust concentrations. An empirical factor was used to estimate chrysotile fiber concentrations from respirable dust concentrations. On a task basis, we found mean 8-h TWA concentrations of respirable dust and chrysotile fibers are numerically highest for specialists, followed by generalists, DIYers, and bystander tradespersons; these concentrations are estimated to be in excess of the respective current but not historical Threshold Limit Values. Due to differences in frequency of activities, annual cumulative exposures are highest for specialists, followed by generalists, bystander tradespersons, and DIYers. Cumulative exposure estimates for chrysotile fibers from drywall finishing are expected to result in few, if any, mesothelioma or excess lung cancer deaths according to recently published risk assessments. Given the dustiness of drywall finishing, we recommend diligence in the use of readily available source controls. © 2014 Society for Risk Analysis.

Lead exposure in the lead-acid storage battery manufacturing and PVC compounding industries.

PubMed

Ho, S F; Sam, C T; Embi, G B

1998-09-01

This study was conducted as part of the Human Exposure Assessment Location (HEAL) Project which comes under the United Nations Environment Programme/World Health Organisation (UNEP/WHO) Global environmental Monitoring System (GEMS). The objective of the study was to evaluate workers' exposure to lead in industries with the highest exposure. All subjects were interviewed about their occupational and smoking histories, the use of personal protective equipment and personal hygiene. The contribution of a dietary source of lead intake from specified foods known to contain lead locally and personal air sampling for lead were assessed. A total of 61 workers from two PVC compounding and 50 workers from two lead acid battery manufacturing plants were studied together with 111 matched controls. In the PVC compounding plants the mean lead-in-air level was 0.0357 mg/m3, with the highest levels occurring during the pouring and mixing operations. This was lower than the mean lead-in-air level of 0.0886 mg/m3 in the lead battery manufacturing plants where the highest exposure was in the loading of lead ingots into milling machines. Workers in lead battery manufacturing had significantly higher mean blood lead than the PVC workers (means, 32.51 and 23.91 mcg/100 ml respectively), but there was poor correlation with lead-in-air levels. Among the lead workers, the Malays had significantly higher blood lead levels than the Chinese (mean blood levels were 33.03 and 25.35 mcg/100 ml respectively) although there was no significant difference between the two ethnic groups in the control group. There were no significant differences between the exposed and control group in terms of dietary intake of specified local foods known to contain lead. However, Malays consumed significantly more fish than the Chinese did. There were no ethnic differences in the hours of overtime work, number of years of exposure, usage of gloves and respirators and smoking habits. Among the Malays, 94.3% eat with

Cumulative toxicity of neonicotinoid insecticide mixtures to Chironomus dilutus under acute exposure scenarios.

PubMed

Maloney, Erin M; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

2017-11-01

Extensive agricultural use of neonicotinoid insecticide products has resulted in the presence of neonicotinoid mixtures in surface waters worldwide. Although many aquatic insect species are known to be sensitive to neonicotinoids, the impact of neonicotinoid mixtures is poorly understood. In the present study, the cumulative toxicities of binary and ternary mixtures of select neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) were characterized under acute (96-h) exposure scenarios using the larval midge Chironomus dilutus as a representative aquatic insect species. Using the MIXTOX approach, predictive parametric models were fitted and statistically compared with observed toxicity in subsequent mixture tests. Single-compound toxicity tests yielded median lethal concentration (LC50) values of 4.63, 5.93, and 55.34 μg/L for imidacloprid, clothianidin, and thiamethoxam, respectively. Because of the similar modes of action of neonicotinoids, concentration-additive cumulative mixture toxicity was the predicted model. However, we found that imidacloprid-clothianidin mixtures demonstrated response-additive dose-level-dependent synergism, clothianidin-thiamethoxam mixtures demonstrated concentration-additive synergism, and imidacloprid-thiamethoxam mixtures demonstrated response-additive dose-ratio-dependent synergism, with toxicity shifting from antagonism to synergism as the relative concentration of thiamethoxam increased. Imidacloprid-clothianidin-thiamethoxam ternary mixtures demonstrated response-additive synergism. These results indicate that, under acute exposure scenarios, the toxicity of neonicotinoid mixtures to C. dilutus cannot be predicted using the common assumption of additive joint activity. Indeed, the overarching trend of synergistic deviation emphasizes the need for further research into the ecotoxicological effects of neonicotinoid insecticide mixtures in field settings, the development of better toxicity models for neonicotinoid mixture

Cumulative Head Impact Exposure Predicts Later-Life Depression, Apathy, Executive Dysfunction, and Cognitive Impairment in Former High School and College Football Players.

PubMed

Montenigro, Philip H; Alosco, Michael L; Martin, Brett M; Daneshvar, Daniel H; Mez, Jesse; Chaisson, Christine E; Nowinski, Christopher J; Au, Rhoda; McKee, Ann C; Cantu, Robert C; McClean, Michael D; Stern, Robert A; Tripodis, Yorghos

2017-01-15

The term "repetitive head impacts" (RHI) refers to the cumulative exposure to concussive and subconcussive events. Although RHI are believed to increase risk for later-life neurological consequences (including chronic traumatic encephalopathy), quantitative analysis of this relationship has not yet been examined because of the lack of validated tools to quantify lifetime RHI exposure. The objectives of this study were: 1) to develop a metric to quantify cumulative RHI exposure from football, which we term the "cumulative head impact index" (CHII); 2) to use the CHII to examine the association between RHI exposure and long-term clinical outcomes; and 3) to evaluate its predictive properties relative to other exposure metrics (i.e., duration of play, age of first exposure, concussion history). Participants included 93 former high school and collegiate football players who completed objective cognitive and self-reported behavioral/mood tests as part of a larger ongoing longitudinal study. Using established cutoff scores, we transformed continuous outcomes into dichotomous variables (normal vs. impaired). The CHII was computed for each participant and derived from a combination of self-reported athletic history (i.e., number of seasons, position[s], levels played), and impact frequencies reported in helmet accelerometer studies. A bivariate probit, instrumental variable model revealed a threshold dose-response relationship between the CHII and risk for later-life cognitive impairment (p < 0.0001), self-reported executive dysfunction (p < 0.0001), depression (p < 0.0001), apathy (p = 0.0161), and behavioral dysregulation (p < 0.0001). Ultimately, the CHII demonstrated greater predictive validity than other individual exposure metrics.

Global approach to reducing lead exposure and poisoning.

PubMed

Meyer, Pamela A; Brown, Mary Jean; Falk, Henry

2008-01-01

Lead poisoning is an important environmental disease that can have life-long adverse health effects. Most susceptible are children, and most commonly exposed are those who are poor and live in developing countries. Studies of children's blood-lead levels (BLLs) are showing cognitive impairment at increasingly lower BLLs. Lead is dangerous at all levels in children. The sources of lead exposure vary among and within countries depending on past and current uses. Sources of lead may be from historic contamination, recycling old lead products, or from manufacturing new products. In all countries that have banned leaded gasoline, average population BLLs have declined rapidly. In many developing countries where leaded gasoline is no longer used, many children and workers are exposed to fugitive emissions and mining wastes. Unexpected lead threats, such as improper disposal of electronics and children's toys contaminated with lead, continue to emerge. The only medical treatment available is chelation, which can save lives of persons with very high BLLs. However, chelating drugs are not always available in developing countries and have limited value in reducing the sequelae of chronic low dose lead exposure. Therefore, the best approach is to prevent exposure to lead. Because a key strategy for preventing lead poisoning is to identify and control or eliminate lead sources, this article highlights several major sources of lead poisoning worldwide. In addition, we recommend three primary prevention strategies for lead poisoning: identify sources, eliminate or control sources, and monitor environmental exposures and hazards.

DIETARY EXPOSURE OF CHILDREN TO LEAD

EPA Science Inventory

Children are the most susceptible population to lead exposure because 1) they have more opportunity for contact with lead sources due to their activities, 2) lead adsorption occurs more readily in a child as compared to an adult, and 3) the child's development is more vulnerable ...

Cumulative Environmental Impacts: Science and Policy to Protect Communities.

PubMed

Solomon, Gina M; Morello-Frosch, Rachel; Zeise, Lauren; Faust, John B

2016-01-01

Many communities are located near multiple sources of pollution, including current and former industrial sites, major roadways, and agricultural operations. Populations in such locations are predominantly low-income, with a large percentage of minorities and non-English speakers. These communities face challenges that can affect the health of their residents, including limited access to health care, a shortage of grocery stores, poor housing quality, and a lack of parks and open spaces. Environmental exposures may interact with social stressors, thereby worsening health outcomes. Age, genetic characteristics, and preexisting health conditions increase the risk of adverse health effects from exposure to pollutants. There are existing approaches for characterizing cumulative exposures, cumulative risks, and cumulative health impacts. Although such approaches have merit, they also have significant constraints. New developments in exposure monitoring, mapping, toxicology, and epidemiology, especially when informed by community participation, have the potential to advance the science on cumulative impacts and to improve decision making.

An Analysis of Cumulative Risks Indicated by Biomonitoring Data of Six Phthalates Using the Maximum Cumulative Ratio

EPA Science Inventory

The Maximum Cumulative Ratio (MCR) quantifies the degree to which a single component of a chemical mixture drives the cumulative risk of a receptor.1 This study used the MCR, the Hazard Index (HI) and Hazard Quotient (HQ) to evaluate co-exposures to six phthalates using biomonito...

Cumulative exposure to work-related traumatic events and current post-traumatic stress disorder in New York City's first responders.

PubMed

Geronazzo-Alman, Lupo; Eisenberg, Ruth; Shen, Sa; Duarte, Cristiane S; Musa, George J; Wicks, Judith; Fan, Bin; Doan, Thao; Guffanti, Guia; Bresnahan, Michaeline; Hoven, Christina W

2017-04-01

Cumulative exposure to work-related traumatic events (CE) is a foreseeable risk for psychiatric disorders in first responders (FRs). Our objective was to examine the impact of work-related CE that could serve as predictor of posttraumatic stress disorder (PTSD) and/or depression in FRs. Cross-sectional examination of previous CE and past-month PTSD outcomes and depression in 209 FRs. Logistic (probable PTSD; probable depression) and Poisson regressions (PTSD score) of the outcomes on work-related CE indexes, adjusting for demographic variables. Differences across occupational groups were also examined. Receiver operating characteristic analysis determined the sensitivity and specificity of CE indexes. All indexes were significantly and differently associated with PTSD; associations with depression were non-significant. The index capturing the sheer number of different incidents experienced regardless of frequency ('Variety') showed conceptual, practical and statistical advantages compared to other indexes. In general, the indexes showed poor to fair discrimination accuracy. Work-related CE is specifically associated with PTSD. Focusing on the variety of exposures may be a simple and effective strategy to predict PTSD in FRs. Further research on sensitivity and specificity of exposure indexes, preferably examined prospectively, is needed and could lead to early identification of individuals at risk. Copyright © 2016 Elsevier Inc. All rights reserved.

Cumulative radiation exposure and associated cancer risk estimates for scoliosis patients: Impact of repetitive full spine radiography.

PubMed

Law, Martin; Ma, Wang-Kei; Lau, Damian; Chan, Eva; Yip, Lawrance; Lam, Wendy

2016-03-01

To quantitatively evaluate the cumulative effective dose and associated cancer risk for scoliotic patients undergoing repetitive full spine radiography during their diagnosis and follow up periods. Organ absorbed doses of full spine exposed scoliotic patients at different age were computer simulated with the use of PCXMC software. Gender specific effective dose was then calculated with the ICRP-103 approach. Values of lifetime attributable cancer risk for patients exposed at different age were calculated for both patient genders and for Asian and Western population. Mathematical fitting for effective dose and for lifetime attributable cancer risk, as function of exposed age, was analytically obtained to quantitatively estimate patient cumulated effective dose and cancer risk. The cumulative effective dose of full spine radiography with posteroanterior and lateral projection for patients exposed annually at age between 5 and 30 years using digital radiography system was calculated as 15mSv. The corresponding cumulative lifetime attributable cancer risk for Asian and Western population was calculated as 0.08-0.17%. Female scoliotic patients would be at a statistically significant higher cumulated cancer risk than male patients under the same full spine radiography protocol. We demonstrate the use of computer simulation and analytic formula to quantitatively obtain the cumulated effective dose and cancer risk at any age of exposure, both of which are valuable information to medical personnel and patients' parents concern about radiation safety in repetitive full spine radiography. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Cumulative trauma and midlife well-being in American women who served in Vietnam: effects of combat exposure and postdeployment social support.

PubMed

Park, Crystal L; Wachen, Jennifer Schuster; Kaiser, Anica Pless; Mager Stellman, Jeanne

2015-01-01

Research increasingly demonstrates that trauma exposure can have cumulative effects, yet much remains to be learned about effects of cumulative trauma, particularly regarding longer term adjustment. One such trauma, combat exposure, is insufficiently understood, especially for women, who are increasingly engaged in professional combat activities. The study comprised a cross-sectional survey assessing multiple aspects of current well-being in women approximately 25 years after their service in Vietnam during the Vietnam War. Participants were 1374 women (78% military and 22% nonmilitary; mean age = 59.7). This study investigated the relations between three separate categories of trauma exposure (childhood, adulthood, and combat) and well-being and examined whether perceived social support at return from Vietnam moderated the association between combat exposure and well-being. While both childhood and adulthood trauma exposure related to midlife well-being, combat exposure still uniquely predicted outcomes. Further, postdeployment perceived social support moderated the association of combat and well-being: recollected higher perceived social support at homecoming buffered participants from the links between combat exposure and well-being. These results may have important implications for interventions to reduce the impact of traumatic experiences, particularly in light of the increasing exposure of women to direct combat events.

Development of a Prototype Optical Hydrogen Gas Sensor Using a Getter-Doped Polymer Transducer for Monitoring Cumulative Exposure: Preliminary Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Small IV, W; Maitland, D J; Wilson, T S

2008-06-05

A novel prototype optical sensor for monitoring cumulative hydrogen gas exposure was fabricated and evaluated. Chemical-to-optical transduction was accomplished by detecting the intensity of 670 nm laser light transmitted through a hydrogen getter-doped polymer film mounted at the end of an optical fiber; the transmittance of the composite film increased with uptake of hydrogen by the embedded getter. The composite film consisted of the hydrogen getter 1,4-bis(phenylethynyl)benzene, also known as DEB, with carbon-supported palladium catalyst embedded in silicone elastomer. Because the change in transmittance was irreversible and occurred continuously as the getter captured hydrogen, the sensor behaved like a dosimeter,more » providing a unique indication of the cumulative gas exposure.« less

Contribution of maternal smoking during pregnancy and lead exposure to early child behavior problems.

PubMed

Wasserman, G A; Liu, X; Pine, D S; Graziano, J H

2001-01-01

Maternal smoking during pregnancy elevates risk for later child behavior problems. Because prior studies considered only Western settings, where smoking co-occurs with social disadvantage, we examined this association in Yugoslavia, a different cultural setting. Mothers enrolled in pregnancy as the low-exposure group in a prospective study of lead exposure were interviewed about health, including smoking history. A total of 199 children were assessed on the Child Behavior Checklist (CBCL) at ages 4, 4 1/2, and 5 years. Average cumulative blood lead (BPb) was determined from serial samples taken biannually since delivery. Longitudinal analyses were derived from 191 children with available data on behavior and covariates. Smoking was unrelated to social adversity. Controlling for age, gender, birthweight, ethnicity, maternal education, and Home Observation for Measurement of the Environment (HOME) Acceptance, smoking was associated with worse scores on almost all subscales; BPb concentration was related to small increases in the Delinquency subscale. Daughters of smokers received significantly higher scores on Somatic Complaints compared to daughters of nonsmokers, consistent with other work relating biological factors and internalizing problems in young girls. Because the present smoking/child behavior associations persist after control for individual and social factors also related to behavior problems, possible biological mediators are considered.

Dietary sources of cumulative phthalates exposure among the U.S. general population in NHANES 2005-2014.

PubMed

Varshavsky, Julia R; Morello-Frosch, Rachel; Woodruff, Tracey J; Zota, Ami R

2018-06-01

Anti-androgenic phthalates are reproductive toxicants that may have additive effects on male development. Diet is the primary exposure source for most phthalates, which contaminate the food supply through food contact materials and industrialized production. To compare dietary sources of cumulative phthalates exposure between "food at home" (e.g. food consumed from a grocery store) and "food away from home" (e.g. food consumed from fast food/restaurants and cafeterias) in the U.S. general population. We estimated cumulative phthalates exposure by calculating daily intake from metabolite concentrations in urinary spot samples for 10,253 participants (≥6 years old) using National Health and Nutrition Examination Survey (NHANES, 2005-2014) data. We constructed a biologically relevant metric of phthalates daily intake (∑androgen-disruptor, μg/kg/day) by converting phthalates into anti-androgen equivalent terms prior to their summation. Particular foods and the percent of total energy intake (TEI) consumed from multiple dining out sources were ascertained from 24-h recall surveys. Associations with ∑androgen-disruptor levels were estimated for children, adolescents, and adults using multivariable linear regression. We observed a consistent positive association between dining out and Σandrogen-disruptor levels across the study population (p-trend <0.0001). Among adolescents, high consumers of foods outside the home had 55% (95% CI: 35%, 78%) higher Σandrogen-disruptor levels compared to those who only consumed food at home. The contribution of specific dining out sources to Σandrogen-disruptor levels varied by age group. For example, cafeteria food was associated with 15% (95% CI: 4.0%, 28%) and 64% (95% CI: 40%, 92%) higher Σandrogen-disruptor levels in children and adults, respectively. Particular foods, especially sandwiches (i.e. cheeseburgers), were associated with increased Σandrogen-disruptor levels only if they were purchased away from home (p�

Cumulative Head Impact Exposure Predicts Later-Life Depression, Apathy, Executive Dysfunction, and Cognitive Impairment in Former High School and College Football Players

PubMed Central

Montenigro, Philip H.; Alosco, Michael L.; Martin, Brett M.; Daneshvar, Daniel H.; Mez, Jesse; Chaisson, Christine E.; Nowinski, Christopher J.; Au, Rhoda; McKee, Ann C.; Cantu, Robert C.; McClean, Michael D.; Tripodis, Yorghos

2017-01-01

Abstract The term “repetitive head impacts” (RHI) refers to the cumulative exposure to concussive and subconcussive events. Although RHI are believed to increase risk for later-life neurological consequences (including chronic traumatic encephalopathy), quantitative analysis of this relationship has not yet been examined because of the lack of validated tools to quantify lifetime RHI exposure. The objectives of this study were: 1) to develop a metric to quantify cumulative RHI exposure from football, which we term the “cumulative head impact index” (CHII); 2) to use the CHII to examine the association between RHI exposure and long-term clinical outcomes; and 3) to evaluate its predictive properties relative to other exposure metrics (i.e., duration of play, age of first exposure, concussion history). Participants included 93 former high school and collegiate football players who completed objective cognitive and self-reported behavioral/mood tests as part of a larger ongoing longitudinal study. Using established cutoff scores, we transformed continuous outcomes into dichotomous variables (normal vs. impaired). The CHII was computed for each participant and derived from a combination of self-reported athletic history (i.e., number of seasons, position[s], levels played), and impact frequencies reported in helmet accelerometer studies. A bivariate probit, instrumental variable model revealed a threshold dose-response relationship between the CHII and risk for later-life cognitive impairment (p < 0.0001), self-reported executive dysfunction (p < 0.0001), depression (p < 0.0001), apathy (p = 0.0161), and behavioral dysregulation (p < 0.0001). Ultimately, the CHII demonstrated greater predictive validity than other individual exposure metrics. PMID:27029716

Lead exposure in radiator repair workers: a survey of Washington State radiator repair shops and review of occupational lead exposure registry data.

PubMed

Whittaker, Stephen G

2003-07-01

Radiator repair workers in Washington State have the greatest number of very elevated (> or =60 microg/dL) blood lead levels of any other worker population. The goals of this study were to determine the number of radiator repair workers potentially exposed to lead; estimate the extent of blood lead data underreporting to the Occupational Lead Exposure Registry; describe current safety and health practices in radiator repair shops; and determine appropriate intervention strategies to reduce exposure and increase employer and worker awareness. Lead exposure in Washington State's radiator repair workers was assessed by reviewing Registry data and conducting a statewide survey of radiator repair businesses. This study revealed that a total of 226 workers in Washington State (including owner-operators and all employees) conduct repair activities that could potentially result in excessive exposures to lead. Approximately 26% of radiator repair workers with elevated blood lead levels (> or =25 microg/dL) were determined to report to Washington State's Registry. This study also revealed a lack of awareness of lead's health effects, appropriate industrial hygiene controls, and the requirements of the Lead Standard. Survey respondents requested information on a variety of workplace health and safety issues and waste management; 80% requested a confidential, free-of-charge consultation. Combining data derived from an occupational health surveillance system and a statewide mail survey proved effective at characterizing lead exposures and directing public health intervention in Washington State.

Peripheral Blood Signatures of Lead Exposure

PubMed Central

LaBreche, Heather G.; Meadows, Sarah K.; Nevins, Joseph R.; Chute, John P.

2011-01-01

Background Current evidence indicates that even low-level lead (Pb) exposure can have detrimental effects, especially in children. We tested the hypothesis that Pb exposure alters gene expression patterns in peripheral blood cells and that these changes reflect dose-specific alterations in the activity of particular pathways. Methodology/Principal Finding Using Affymetrix Mouse Genome 430 2.0 arrays, we examined gene expression changes in the peripheral blood of female Balb/c mice following exposure to per os lead acetate trihydrate or plain drinking water for two weeks and after a two-week recovery period. Data sets were RMA-normalized and dose-specific signatures were generated using established methods of supervised classification and binary regression. Pathway activity was analyzed using the ScoreSignatures module from GenePattern. Conclusions/Significance The low-level Pb signature was 93% sensitive and 100% specific in classifying samples a leave-one-out crossvalidation. The high-level Pb signature demonstrated 100% sensitivity and specificity in the leave-one-out crossvalidation. These two signatures exhibited dose-specificity in their ability to predict Pb exposure and had little overlap in terms of constituent genes. The signatures also seemed to reflect current levels of Pb exposure rather than past exposure. Finally, the two doses showed differential activation of cellular pathways. Low-level Pb exposure increased activity of the interferon-gamma pathway, whereas high-level Pb exposure increased activity of the E2F1 pathway. PMID:21829687

Low level lead exposure: history and discovery.

PubMed

Needleman, Herbert

2009-04-01

The history of lead toxicity spans 2 millennnia. With increasingly sensitive methods, deficits due to lead exposure have been demonstrated at lower and lower doses. Persuasive evidence suggests that no threshold for lead toxicity exists.

Anxiety and depression following cumulative low-level exposure to organophosphate pesticides.

PubMed

Harrison, Virginia; Mackenzie Ross, Sarah

2016-11-01

Previous research suggests that individuals with a prior history of pesticide poisoning are at increased risk of psychiatric disorder (Freire and Koifman, 2013), but findings regarding the impact of cumulative low-level exposure are inconsistent. The aim of the current study was to investigate whether sheep farmers with a history of low-level exposure to organophosphate pesticides (1) report a higher level of psychological distress on subjective symptom questionnaires, compared to unexposed controls (2) also meet internationally agreed diagnostic criteria for a psychiatric disorder more often than unexposed controls. 127sheep farmers were evaluated and compared to 78 unexposed controls, matched in terms of gender, education, level of intelligence, working status and area of residence. Both self-report measures and structured clinical interviews were used to assess mental health. The exposed cohort reported significantly higher rates of anxiety and depression when self-report questionnaires were used to evaluate mood, even when stressful life events, demographic and physical health factors were taken into account. However, when diagnostic interviews were used to assess mood, this pattern only held true for anxiety. Copyright © 2016 Elsevier Inc. All rights reserved.

Sources of lead exposure in Mexico City.

PubMed Central

Romieu, I; Palazuelos, E; Hernandez Avila, M; Rios, C; Muñoz, I; Jimenez, C; Cahero, G

1994-01-01

Many countries, including Mexico, are facing a largely unrecognized epidemic of low-level lead poisoning. Mexico is the sixth largest lead-producing country in the world, and 40% of its production is used locally in different industrial processes that cause lead contamination of the environment. The major sources and pathways of lead exposure among the Mexican population are gasoline emissions, lead-glazed ceramics, leaded paint, and lead in canned foods and beverages. In this paper we present evidence for the presence of lead in different environmental media and its impact on blood lead levels of the Mexican population. Although during the last few years important measures have been implemented to decrease lead exposure, our findings suggest that lead poisoning is still an important problem in Mexico. There is an urgent need for regulatory policies that implement stricter control to protect the Mexican population. There is also a need to develop adequate programs to reduce the lead burden and the associated health effects in the population that has been chronically exposed. Images Figure 1. PMID:7523102

Sources of lead exposure in Mexico City.

PubMed

Romieu, I; Palazuelos, E; Hernandez Avila, M; Rios, C; Muñoz, I; Jimenez, C; Cahero, G

1994-04-01

Many countries, including Mexico, are facing a largely unrecognized epidemic of low-level lead poisoning. Mexico is the sixth largest lead-producing country in the world, and 40% of its production is used locally in different industrial processes that cause lead contamination of the environment. The major sources and pathways of lead exposure among the Mexican population are gasoline emissions, lead-glazed ceramics, leaded paint, and lead in canned foods and beverages. In this paper we present evidence for the presence of lead in different environmental media and its impact on blood lead levels of the Mexican population. Although during the last few years important measures have been implemented to decrease lead exposure, our findings suggest that lead poisoning is still an important problem in Mexico. There is an urgent need for regulatory policies that implement stricter control to protect the Mexican population. There is also a need to develop adequate programs to reduce the lead burden and the associated health effects in the population that has been chronically exposed.

[Blood cerebrospinal fluid barrier damage of rats induced by lead acetate or nano-lead exposure].

PubMed

Feng, P P; Zhai, F J; Jiang, S F; Wu, J Z; Xue, L; Zheng, M M; Zhou, L L; Meng, C Y; Cao, M Y; Zhang, Y S

2016-05-20

To investigate the damage of blood-cerebrospinal fluid barrier (BCB) of rats induced by lead and nano-lead exposure in order to provide the basis for mechanism study of lead neurotoxicity. 39 male rats were randomly divided into control group, lead acetate exposed group and nano-lead exposed group. Rats in lead acetate exposed group and nano-lead exposed group were given 20 mg/kg lead acetate or nano-lead by oral gavage and rats in control groups were given the same amount saline for 9 weeks.Morris maze was used to test the learning function, serum albumin and CSF albumin were determined by ELISA. Confocal laser scanning microscope was applied to detect ZO-1 and Occludin protein expression in choroid plexus, real time-PCR was used to test the expression of ZO-1 and Occludin mRNA expression. Pathological changes of choroid plexus cells were observed by the electron microscopy. Compared with the control group, the escape latency of rats in lead acetate or nano-lead exposure group were longer and times of across platform were less. The levels of CSF albumin and the CSF albumin index in lead acetate or nano-lead exposed rats were obviously higher, and the fluorescence intensity of ZO-1, Occludin as well as mRNA expressions were lower than those in control group(P<0.05). Compared with lead acetate exposed group, the levels of CSF albumin and the CSF albumin index in nano-lead exposure group were higher. The fluorescence intensity and mRNA expressions of ZO-1, Occludin in nano-lead exposure group were than those in lead acetate group(P<0.05). Electron microscopy revealed that lead acetate or nano-lead exposure could induce shorter microvillus of choroid plexus epithelial cells, mitochondrion destruction and partial disconnection in intracellular junctions between two adjacent epithelial cells. Lead acetate and nano-lead exposed can result in the blood-cerebrospinal fluid barrier damage, which may involve in the process of lead induced neurotoxicity. Meanwhile, nano-lead

Lead exposure in Canada geese of the Eastern Prairie Population

USGS Publications Warehouse

DeStefano, S.; Brand, C.J.; Rusch, D.H.; Finley, Daniel L.; Gillespie, M.M.

1991-01-01

We monitored lead exposure in Eastern Prairie Population Canada geese during summer-winter, 1986-1987 and 1987-1988 at 5 areas. Blood lead concentrations in geese trapped during summer at Cape Churchill Manitoba were below levels indicative of recent lead exposure (0.18 ppm). Geese exposed to lead (≥0.18 ppm blood lead) increased to 7.6% at Oak Hammock Wildlife Management Area (WMA), southern Manitoba, where lead shot was still in use, and to 10.0% at Roseau River WMA, northern Minnesota, when fall-staging geese were close to a source of lead shot in Manitoba. Proportion of birds exposed to lead dropped to <2% at Lac Qui Parle WMA, Minnesota, a steel shot zone since 1980. On the wintering grounds at Swan Lake National Wildlife Refuge in Missouri, 4.9% of all geese showed exposure to lead before the hunting season. Lead exposure rose to 10.0% after hunting ended and then decreased to 5.2% in late winter. Incidence of lead shot in gizzards and concentrations of lead in livers supported blood assay data. Soil samples indicated that lead shot continues to be available to geese at Swan Lake, even though the area was established as a non-toxic shot zone in 1978. Steel shot zones have reduced lead exposure in the Eastern Prairie Population, but lead shot persists in the environment and continues to account for lead exposure and mortality in Eastern Prairie Population Canada geese.

Dietary exposure to lead of adults in Shenzhen city, China.

PubMed

Pan, Liubo; Wang, Zhou; Peng, Zhaoqiong; Liu, Guihua; Zhang, Huimin; Zhang, Jinzhou; Jiang, Jie; Pathiraja, Nimal; Xiao, Ying; Jiao, Rui; Huang, Wei

2016-07-01

Lead, a ubiquitous heavy metal, can be found in the environment and food. The present study is the first to estimate the lead dietary exposure of Shenzhen adults (≥ 20 years old) in various age-gender subgroups, and to assess the associated health risk. Food samples that represented the Shenzhen people's dietary pattern were collected and prepared for analysis. Lead was determined in 13 food groups using 276 individual cooked samples by inductively coupled plasma-mass spectrometry (ICP-MS). Dietary exposures were estimated by combining the analytical results with the local food consumption data of Shenzhen adults. The mean and 95th percentile lead exposure of Shenzhen adults were 0.59-0.73 and 0.75-0.94 μg kg(-1) bw day(-1), respectively. In all food groups, the highest lead exposure was from 'Eggs and their products' (42.4-51.6% of the total exposure); preserved eggs being the main contributor. The other major contributors to lead exposure of Shenzhen adults were 'Fish and seafood, and their products' (14.3-16.7% of the total exposure) and 'Vegetables and their products' (15.5-16.2% of the total exposure). The margin of exposure (MOE) approach was used for the risk assessment of lead, and the results showed that the risk was considered to be low in all age-gender groups for Shenzhen adults. However, having considered a number of toxic effects of lead, it is suggested that more efforts should be made to reduce the lead levels in foodstuff for Shenzhen adults.

Effects of exposure to lead among lead-acid battery factory workers in Sudan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohamed, A.A.E.K.; Hamed, A.A.S.; Elhaimi, Y.A.A.

Health effects of occupational exposure to lead were investigated among 92 exposed workers in lead-acid battery factory and 40 nonexposed workers serving as a control group from an oil mill in Khartoum North industrial area. The two groups were closely similar in age, stature, body weight, and socioeconomic conditions. A highly significant increase (P<.01) was recorded in blood lead, urinary coproporphyrin, and basophilic stippled red blood cells of the exposed group in comparison to the control group. Central nervous system symptoms (insomnia, fatigue, weakness, and drowsiness) were reported by 50% and other symptoms such as abdominal colic and constipation weremore » reported by 41% of the exposed group. Blue line on the gum was detected only on 2% of the exposed group. Strong associations between exposure to lead and the prevalence of central nervous system symptoms, abdominal colic, and constipation were recorded. Exposure to exceedingly high levels of lead in the working environment causes adverse health effects.« less

A Screening Method for Assessing Cumulative Impacts

PubMed Central

Alexeeff, George V.; Faust, John B.; August, Laura Meehan; Milanes, Carmen; Randles, Karen; Zeise, Lauren; Denton, Joan

2012-01-01

The California Environmental Protection Agency (Cal/EPA) Environmental Justice Action Plan calls for guidelines for evaluating “cumulative impacts.” As a first step toward such guidelines, a screening methodology for assessing cumulative impacts in communities was developed. The method, presented here, is based on the working definition of cumulative impacts adopted by Cal/EPA [1]: “Cumulative impacts means exposures, public health or environmental effects from the combined emissions and discharges in a geographic area, including environmental pollution from all sources, whether single or multi-media, routinely, accidentally, or otherwise released. Impacts will take into account sensitive populations and socio-economic factors, where applicable and to the extent data are available.” The screening methodology is built on this definition as well as current scientific understanding of environmental pollution and its adverse impacts on health, including the influence of both intrinsic, biological factors and non-intrinsic socioeconomic factors in mediating the effects of pollutant exposures. It addresses disparities in the distribution of pollution and health outcomes. The methodology provides a science-based tool to screen places for relative cumulative impacts, incorporating both the pollution burden on a community- including exposures to pollutants, their public health and environmental effects- and community characteristics, specifically sensitivity and socioeconomic factors. The screening methodology provides relative rankings to distinguish more highly impacted communities from less impacted ones. It may also help identify which factors are the greatest contributors to a community’s cumulative impact. It is not designed to provide quantitative estimates of community-level health impacts. A pilot screening analysis is presented here to illustrate the application of this methodology. Once guidelines are adopted, the methodology can serve as a screening

Dose-response relationship between cumulative physical workload and osteoarthritis of the hip - a meta-analysis applying an external reference population for exposure assignment.

PubMed

Seidler, Andreas; Lüben, Laura; Hegewald, Janice; Bolm-Audorff, Ulrich; Bergmann, Annekatrin; Liebers, Falk; Ramdohr, Christina; Romero Starke, Karla; Freiberg, Alice; Unverzagt, Susanne

2018-06-01

There is consistent evidence from observational studies of an association between occupational lifting and carrying of heavy loads and the diagnosis of hip osteoarthritis. However, due to the heterogeneity of exposure estimates considered in single studies, a dose-response relationship between cumulative physical workload and hip osteoarthritis could not be determined so far. This study aimed to analyze the dose-response relationship between cumulative physical workload and hip osteoarthritis by replacing the exposure categories of the included studies with cumulative exposure values of an external reference population. Our meta-regression analysis was based on a recently conducted systematic review (Bergmann A, Bolm-Audorff U, Krone D, Seidler A, Liebers F, Haerting J, Freiberg A, Unverzagt S, Dtsch Arztebl Int 114:581-8, 2017). The main analysis of our meta-regression comprised six case-control studies for men and five for women. The population control subjects of a German multicentre case-control study (Seidler A, Bergmann A, Jäger M, Ellegast R, Ditchen D, Elsner G, Grifka J, Haerting J, Hofmann F, Linhardt O, Luttmann A, Michaelis M, Petereit-Haack G, Schumann B, Bolm-Audorff U, BMC Musculoskelet Disord 10:48, 2009) served as the reference population. Based on the sex-specific cumulative exposure percentiles of the reference population, we assigned exposure values to each category of the included studies using three different cumulative exposure parameters. To estimate the doubling dose (the amount of physical workload to double the risk of hip osteoarthritis) on the basis of all available case-control-studies, meta-regression analyses were conducted based on the linear association between exposure values of the reference population and the logarithm of reported odds ratios (ORs) from the included studies. In men, the risk to develop hip osteoarthritis was increased by an OR of 1.98 (95% CI 1.20-3.29) per 10,000 tons of weights ≥20 kg handled, 2.08 (95% CI

Environmental urban lead exposure and blood lead levels in children of Mexico City.

PubMed Central

Romieu, I; Carreon, T; Lopez, L; Palazuelos, E; Rios, C; Manuel, Y; Hernandez-Avila, M

1995-01-01

Lead contamination is now a leading public health problem in Mexico. However, there are few data on the lead content of various environmental sources, and little is known about the contribution of these sources to the total lead exposure in the population of children residing in Mexico City. We conducted a cross-sectional study in a random sample of 200 children younger than 5 years of age who lived in one of two areas of Mexico City. Environmental samples of floor, window, and street dust, paint, soil, water, and glazed ceramics were obtained from the participants' households, as well as blood samples and dirt from the hands of the children. Blood lead levels ranged from 1 to 31 micrograms/dl with a mean of 9.9 micrograms/dl (SD 5.8 micrograms/dl). Forty-four percent of the children 18 months of age or older had blood lead levels exceeding 10 micrograms/dl. The lead content of environmental samples was low, except in glazed ceramic. The major predictors of blood lead levels were the lead content of the glazed ceramics used to prepare children's food, exposure to airborne lead due to vehicular emission, and the lead content of the dirt from the children's hands. We conclude that the major sources of lead exposure in Mexico City could be controlled by adequate public health programs to reinforce the use of unleaded gasoline and to encourage production and use of unleaded cookware instead of lead-glazed ceramics. PMID:8605853

Feather lead concentrations and (207)Pb/(206)Pb ratios reveal lead exposure history of California Condors (Gymnogyps californianus).

PubMed

Finkelstein, M E; George, D; Scherbinski, S; Gwiazda, R; Johnson, M; Burnett, J; Brandt, J; Lawrey, S; Pessier, A P; Clark, M; Wynne, J; Grantham, J; Smith, D R

2010-04-01

Lead poisoning is a primary factor impeding the survival and recovery of the critically endangered California Condor (Gymnogyps californianus). However, the frequency and magnitude of lead exposure in condors is not well-known in part because most blood lead monitoring occurs biannually, and biannual blood samples capture only approximately 10% of a bird's annual exposure history. We investigated the use of growing feathers from free-flying condors in California to establish a bird's lead exposure history. We show that lead concentration and stable lead isotopic composition analyses of sequential feather sections and concurrently collected blood samples provided a comprehensive history of lead exposure over the 2-4 month period of feather growth. Feather analyses identified exposure events not evident from blood monitoring efforts, and by fitting an empirically derived timeline to actively growing feathers, we were able to estimate the time frame for specific lead exposure events. Our results demonstrate the utility of using sequentially sampled feathers to reconstruct lead exposure history. Since exposure risk in individuals is one determinant of population health, our findings should increase the understanding of population-level effects from lead poisoning in condors; this information may also be helpful for other avian species potentially impacted by lead poisoning.

Feather lead concentrations and 207Pb/206Pb ratios reveal lead exposure history of California Condors (Gymnogyps californianus)

USGS Publications Warehouse

Finkelstein, M.E.; George, D.; Scherbinski, S.; Gwiazda, R.; Johnson, M.; Burnett, J.; Brandt, J.; Lawrey, S.; Pessier, Allan P.; Clark, M.R.; Wynne, J.; Grantham, And J.; Smith, D.R.

2010-01-01

Lead poisoning is a primary factor impeding the survival and recovery of the critically endangered California Condor (Gymnogyps californianus). However, the frequency and magnitude of lead exposure in condors is not well-known in part because most blood lead monitoring occurs biannually, and biannual blood samples capture only ∼10% of a bird’s annual exposure history. We investigated the use of growing feathers from free-flying condors in California to establish a bird’s lead exposure history. We show that lead concentration and stable lead isotopic composition analyses of sequential feather sections and concurrently collected blood samples provided a comprehensive history of lead exposure over the 2−4 month period of feather growth. Feather analyses identified exposure events not evident from blood monitoring efforts, and by fitting an empirically derived timeline to actively growing feathers, we were able to estimate the time frame for specific lead exposure events. Our results demonstrate the utility of using sequentially sampled feathers to reconstruct lead exposure history. Since exposure risk in individuals is one determinant of population health, our findings should increase the understanding of population-level effects from lead poisoning in condors; this information may also be helpful for other avian species potentially impacted by lead poisoning.

Lead exposure in Nunavik: from research to action

PubMed Central

Couture, Ariane; Levesque, Benoît; Dewailly, Éric; Muckle, Gina; Déry, Serge; Proulx, Jean-François

2012-01-01

Background In 1999, the Government of Canada regulated the use of lead shot for hunting. Concurrently, the Nunavik Regional Board of Health and Social Services (NRBHSS) was informed of the results of an isotope study that pointed to lead ammunition as a likely source of lead exposure in Nunavik. Rapidly thereafter, a coalition for the banning of lead shot was implemented by the NRBHSS as well as by regional/local partners and by Inuit hunters in order to disseminate this information to the public. Objectives The purpose of this article is to describe the intervention conducted in the winter of 1999 by the NRBHSS and to assess the combined impact of national legislation and an awareness campaign on blood lead levels in Nunavik. Study design Impact assessment of the intervention for the banning of lead shot conducted in 1999 in Nunavik using blood lead levels data before and after the intervention. Methods Data on blood lead levels in Nunavik describing foetal exposure as well as during childhood and in adults published between 1992 and 2009 were compiled. Blood lead levels in Nunavik prior to and after the interventions were compared. To assess the current situation, the most recent blood lead levels were compared with those from surveys conducted during the same period in North America. Results Analysis of blood samples collected from umbilical cord and from adults show that blood lead levels in Nunavik significantly declined between 1992 and 2004. Nevertheless, lead exposure in Nunavik still remains higher in comparison to that observed in other North American surveys. Conclusions The current situation regarding lead exposure in Nunavik has significantly improved as a result of the implemented intervention. However, according to recent data, a gap still subsists relative to other North American populations. PMID:22818717

The intersection of aggregate-level lead exposure and crime.

PubMed

Boutwell, Brian B; Nelson, Erik J; Emo, Brett; Vaughn, Michael G; Schootman, Mario; Rosenfeld, Richard; Lewis, Roger

2016-07-01

Childhood lead exposure has been associated with criminal behavior later in life. The current study aimed to analyze the association between elevated blood lead levels (n=59,645) and crime occurrence (n=90,433) across census tracts within St. Louis, Missouri. Longitudinal ecological study. Saint Louis, Missouri. Blood lead levels. Violent, Non-violent, and total crime at the census tract level. Spatial statistical models were used to account for the spatial autocorrelation of the data. Greater lead exposure at the census-tract level was associated with increased violent, non-violent, and total crime. In addition, we examined whether non-additive effects existed in the data by testing for an interaction between lead exposure and concentrated disadvantage. Some evidence of a negative interaction emerged, however, it failed to reach traditional levels of statistical significance (supplementary models, however, revealed a similar negative interaction that was significant). More precise measurements of lead exposure in the aggregate, produced additional evidence that lead is a potent predictor of criminal outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Occupational exposure to airborne lead in Brazilian police officers.

PubMed

Rocha, Ernesto Díaz; Sarkis, Jorge E Souza; Carvalho, Maria de Fátima H; Santos, Gerson Vechio Dos; Canesso, Claudemir

2014-07-01

Shooting with lead-containing ammunition in indoor firing ranges is a known source of lead exposure in adults. Police officers may be at risk of lead intoxication when regular training shooting exercises are yearly mandatory to law enforcement officers. Effects on health must be documented, even when low-level elemental (inorganic) lead exposure is detected. Forty police officers (nineteen cadets and twenty-one instructors) responded to a questionnaire about health, shooting habits, and potential lead exposure before a training curse. Blood samples were collected and analyzed for blood lead level (BLL) before and after a three days training curse. The mean BLL for the instructors' group was 5.5 μg/dL ± 0.6. The mean BLL for the cadets' group before the training was 3.3 μg/dL ± 0.15 and after the training the main BLL was 18.2 μg/d L± 1.5. Samples were analyzed by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). All the participants in the training curse had significantly increased BLL (mean increment about 15 μg/dL) after the three days indoor shooting season. In conclusion, occupational lead exposure in indoor firing ranges is a source of lead exposure in Brazilian police officers, and appears to be a health risk, especially when heavy weapons with lead-containing ammunition are used in indoor environments during the firing training seasons. Copyright © 2013 Elsevier GmbH. All rights reserved.

Incorporating Nonchemical Stressors Into Cumulative Risk Assessments

PubMed Central

Rider, Cynthia V.; Dourson, Michael L.; Hertzberg, Richard C.; Mumtaz, Moiz M.; Price, Paul S.; Simmons, Jane Ellen

2012-01-01

The role of nonchemical stressors in modulating the human health risk associated with chemical exposures is an area of increasing attention. On 9 March 2011, a workshop titled “Approaches for Incorporating Nonchemical Stressors into Cumulative Risk Assessment” took place during the 50th Anniversary Annual Society of Toxicology Meeting in Washington D.C. Objectives of the workshop included describing the current state of the science from various perspectives (i.e., regulatory, exposure, modeling, and risk assessment) and presenting expert opinions on currently available methods for incorporating nonchemical stressors into cumulative risk assessments. Herein, distinct frameworks for characterizing exposure to, joint effects of, and risk associated with chemical and nonchemical stressors are discussed. PMID:22345310

Lead exposures in U.S. Children, 2008: implications for prevention.

PubMed

Levin, Ronnie; Brown, Mary Jean; Kashtock, Michael E; Jacobs, David E; Whelan, Elizabeth A; Rodman, Joanne; Schock, Michael R; Padilla, Alma; Sinks, Thomas

2008-10-01

We reviewed the sources of lead in the environments of U.S. children, contributions to children's blood lead levels, source elimination and control efforts, and existing federal authorities. Our context is the U.S. public health goal to eliminate pediatric elevated blood lead levels (EBLs) by 2010. National, state, and local exposure assessments over the past half century have identified risk factors for EBLs among U.S. children, including age, race, income, age and location of housing, parental occupation, and season. Recent national policies have greatly reduced lead exposure among U.S. children, but even very low exposure levels compromise children's later intellectual development and lifetime achievement. No threshold for these effects has been demonstrated. Although lead paint and dust may still account for up to 70% of EBLs in U.S. children, the U.S. Centers for Disease Control and Prevention estimates that >or=30% of current EBLs do not have an immediate lead paint source, and numerous studies indicate that lead exposures result from multiple sources. EBLs and even deaths have been associated with inadequately controlled sources including ethnic remedies and goods, consumer products, and food-related items such as ceramics. Lead in public drinking water and in older urban centers remain exposure sources in many areas. Achieving the 2010 goal requires maintaining current efforts, especially programs addressing lead paint, while developing interventions that prevent exposure before children are poisoned. It also requires active collaboration across all levels of government to identify and control all potential sources of lead exposure, as well as primary prevention.

Modeling Joint Exposures and Health Outcomes for Cumulative Risk Assessment: The Case of Radon and Smoking

PubMed Central

Chahine, Teresa; Schultz, Bradley D.; Zartarian, Valerie G.; Xue, Jianping; Subramanian, SV; Levy, Jonathan I.

2011-01-01

Community-based cumulative risk assessment requires characterization of exposures to multiple chemical and non-chemical stressors, with consideration of how the non-chemical stressors may influence risks from chemical stressors. Residential radon provides an interesting case example, given its large attributable risk, effect modification due to smoking, and significant variability in radon concentrations and smoking patterns. In spite of this fact, no study to date has estimated geographic and sociodemographic patterns of both radon and smoking in a manner that would allow for inclusion of radon in community-based cumulative risk assessment. In this study, we apply multi-level regression models to explain variability in radon based on housing characteristics and geological variables, and construct a regression model predicting housing characteristics using U.S. Census data. Multi-level regression models of smoking based on predictors common to the housing model allow us to link the exposures. We estimate county-average lifetime lung cancer risks from radon ranging from 0.15 to 1.8 in 100, with high-risk clusters in areas and for subpopulations with high predicted radon and smoking rates. Our findings demonstrate the viability of screening-level assessment to characterize patterns of lung cancer risk from radon, with an approach that can be generalized to multiple chemical and non-chemical stressors. PMID:22016710

Integrating human health and ecological data into cumulative risk assessment through the Aggregate Exposure Pathway and Adverse Outcome Pathway frameworks

EPA Science Inventory

Cumulative risk assessment (CRA) methods promote the use of a conceptual site model (CSM) to apportion exposures and integrate risk from relevant stressors across different species. Integration is important to provide a more complete assessment of risk, but evaluating endpoints a...

Testing for lead in toys at day care centers.

PubMed

Sanders, Martha; Stolz, Julie; Chacon-Baker, Ashley

2013-01-01

Exposure to lead-based paint or material has been found to impact children's cognitive and behavioral development at blood lead levels far below current standards. The purpose of the project was to screen for lead in toy items in daycare centers in order to raise awareness of inside environmental lead exposures and minimize lead-based exposures for children. Occupational therapy students in a service learning class tested for lead in ten daycare or public centers using the XRF Thermo Scientific Niton XL3t, a method accepted by the Consumer Product Safety Commission (CPSC). A total of 460 items were tested over a two-month period for an average of 66 toys per setting. Fifty six (56) items tested > 100 ppm, which represented 12% of the entire sample. Items with high lead levels included selected toys constructed with lead-based paint, lead metals, plastics using lead as a color enhancer, and decorative objects. While the actual number of lead-based products is small, the cumulative exposure or habitual use may pose an unnecessary risk to children. Indoor exposures occurred for all day care centers regardless of socio-economic levels. Recommendations to minimize exposures are provided.

Childhood lead exposure and sexually transmitted infections: New evidence.

PubMed

Nelson, Erik J; Shacham, Enbal; Boutwell, Brian B; Rosenfeld, Richard; Schootman, Mario; Vaughn, Michael; Lewis, Roger

2015-11-01

The adverse health effects of lead exposure in children are well documented and include intellectual and behavioral maladies. Childhood lead exposure has also been linked to impulsive behaviors, which, in turn, are associated with a host of negative health outcomes including an increased risk for sexually transmitted infections (STI). The purpose of this study was to assess the association of lead exposure with STI rates across census tracts in St. Louis City, Missouri. Incident cases of gonorrhea and chlamydia (GC) during 2011 were identified from the Missouri Department of Health and Senior Services and aggregated by census tract. We also geocoded the home address of 59,645 children >72 months in age who had blood lead level tests performed in St. Louis City from 1996 to 2007. Traditional regression and Bayesian spatial models were used to determine the relationship between GC and lead exposure while accounting for confounders (condom and alcohol availability, crime, and an index of concentrated disadvantage). Incident GC rates were found to cluster across census tracts (Moran's I=0.13, p=0.006). After accounting for confounders and their spatial dependence, a linear relationship existed between lead exposure and GC incidence across census tracts, with higher GC rates occurring in the northern part of St. Louis City At the census-tract level, higher lead exposure is associated with higher STI rates. Visualizing these patterns through maps may help deliver targeted interventions to reduce geographic disparities in GC rates. Copyright © 2015 Elsevier Inc. All rights reserved.

Lead absorption in indoor firing range users.

PubMed Central

Valway, S E; Martyny, J W; Miller, J R; Cook, M; Mangione, E J

1989-01-01

To determine if users of indoor firing ranges may be at risk from lead exposure, we studied a law enforcement trainee class during three months of firearms instruction. Blood lead levels were obtained before training and at four-week intervals during training. Air lead levels were measured three times during instruction. Blood lead levels rose from a pre-training mean of 0.31 mumol/L to 2.47 mumol/L. Mean air lead levels were above 2,000 micrograms/m3, more than 40 times the Occupational Safety and Health Administration's standard of 50 micrograms/m3. Cumulative exposure to lead and the change in blood lead were positively correlated. Control measures need to be studied to determine their efficacy in decreasing or eliminating this health risk. PMID:2751019

Lead Exposures in U.S. Children, 2008: Implications for Prevention

PubMed Central

Levin, Ronnie; Brown, Mary Jean; Kashtock, Michael E.; Jacobs, David E.; Whelan, Elizabeth A.; Rodman, Joanne; Schock, Michael R.; Padilla, Alma; Sinks, Thomas

2008-01-01

Objective We reviewed the sources of lead in the environments of U.S. children, contributions to children’s blood lead levels, source elimination and control efforts, and existing federal authorities. Our context is the U.S. public health goal to eliminate pediatric elevated blood lead levels (EBLs) by 2010. Data sources National, state, and local exposure assessments over the past half century have identified risk factors for EBLs among U.S. children, including age, race, income, age and location of housing, parental occupation, and season. Data extraction and synthesis Recent national policies have greatly reduced lead exposure among U.S. children, but even very low exposure levels compromise children’s later intellectual development and lifetime achievement. No threshold for these effects has been demonstrated. Although lead paint and dust may still account for up to 70% of EBLs in U.S. children, the U.S. Centers for Disease Control and Prevention estimates that ≥30% of current EBLs do not have an immediate lead paint source, and numerous studies indicate that lead exposures result from multiple sources. EBLs and even deaths have been associated with inadequately controlled sources including ethnic remedies and goods, consumer products, and food-related items such as ceramics. Lead in public drinking water and in older urban centers remain exposure sources in many areas. Conclusions Achieving the 2010 goal requires maintaining current efforts, especially programs addressing lead paint, while developing interventions that prevent exposure before children are poisoned. It also requires active collaboration across all levels of government to identify and control all potential sources of lead exposure, as well as primary prevention. PMID:18941567

Associations between parenting, media use, cumulative risk, and children's executive functioning.

PubMed

Linebarger, Deborah L; Barr, Rachel; Lapierre, Matthew A; Piotrowski, Jessica T

2014-01-01

This study was designed to examine how parenting style, media exposure, and cumulative risk were associated with executive functioning (EF) during early childhood. A nationally representative group of US parents/caregivers (N = 1156) with 1 child between 2 and 8 years participated in a telephone survey. Parents were asked to report on their child's exposure to television, music, and book reading through a 24-hour time diary. Parents also reported a host of demographic and parenting variables as well as questions on their child's EF. Separate multiple regressions for preschool (2-5 years) and school-aged (6-8 years) children grouped by cumulative risk were conducted. Parenting style moderated the risks of exposure to background television on EF for high-risk preschool-age children. Educational TV exposure served as a buffer for high-risk school-aged children. Cumulative risk, age, and parenting quality interacted with a number of the exposure effects. The study showed a complex pattern of associations between cumulative risk, parenting, and media exposure with EF during early childhood. Consistent with the American Academy of Pediatrics, these findings support the recommendation that background television should be turned off when a child is in the room and suggest that exposure to high-quality content across multiple media platforms may be beneficial.

The identification of lead ammunition as a source of lead exposure in First Nations: the use of lead isotope ratios.

PubMed

Tsuji, Leonard J S; Wainman, Bruce C; Martin, Ian D; Sutherland, Celine; Weber, Jean-Philippe; Dumas, Pierre; Nieboer, Evert

2008-04-15

The use of lead shotshell to hunt water birds has been associated with lead-contamination in game meat. However, evidence illustrating that lead shotshell is a source of lead exposure in subsistence hunting groups cannot be deemed definitive. This study seeks to determine whether lead shotshell constitutes a source of lead exposure using lead isotope ratios. We examined stable lead isotope ratios for lichens, lead shotshell and bullets, and blood from residents of Fort Albany and Kashechewan First Nations, and the City of Hamilton, Ontario, Canada. Data were analyzed using ANOVA and regression analyses. ANOVA of isotope ratios for blood revealed significant differences with respect to location, but not sex. Hamilton differed from both Kashechewan and Fort Albany; however, the First Nations did not differ from each other. ANOVA of the isotope ratios for lead ammunition and lichens revealed no significant differences between lichen groups (north and south) and for the lead ammunition sources (pellets and bullets). A plot of (206)Pb/(204)Pb and (206)Pb/(207)Pb values illustrated that lichens and lead ammunition were distinct groupings and only the 95% confidence ellipse of the First Nations group overlapped that of lead ammunition. In addition, partial correlations between blood-lead levels (adjusted for age) and isotope ratios revealed significant (p<0.05) positive correlations for (206)Pb/(204)Pb and (206)Pb/(207)Pb, and a significant negative correlation for (208)Pb/(206)Pb, as predicted if leaded ammunition were the source of lead exposure. In conclusion, lead ammunition was identified as a source of lead exposure for First Nations people; however, the isotope ratios for lead shotshell pellets and bullets were indistinguishable. Thus, lead-contaminated meat from game harvested with lead bullets may also be contributing to the lead body burden.

Control of excessive lead exposure in radiator repair workers.

PubMed

1991-03-01

In 1988, 83 automotive repair workers with blood lead levels (BLLs) greater than 25 micrograms/dL were reported to state health departments in the seven states that collaborated with CDC's National Institute for Occupational Safety and Health (NIOSH) in maintaining registries of elevated BLLs in adults. In 18 (22%) of these 83 persons, BLLs were greater than 50 micrograms/dL. Among automotive repair workers for whom a job category was specified, radiator repair work was the principal source of lead exposure. The major sources of exposure for radiator repair workers are lead fumes generated during soldering and lead dust produced during radiator cleaning. This report summarizes current BLL surveillance data for radiator repair workers and describes three control technologies that are effective in reducing lead exposures in radiator repair shops.

Primary prevention of lead exposure: the Philadelphia lead safe homes study.

PubMed

Campbell, Carla; Tran, Mary; Gracely, Edward; Starkey, Naomi; Kersten, Hans; Palermo, Peter; Rothman, Nancy; Line, Laura; Hansen-Turton, Tine

2011-01-01

Lead exposure in children can lead to neuropsychological impairment. This study tested whether primary prevention interventions in the newborn period prevent elevated blood lead levels (BLLs). The Philadelphia Lead Safe Homes (LSH) Study offered parental education, home evaluation, and lead remediation to the families of urban newborns. Households were randomized to a standard lead education group or maintenance education group. We conducted home visits at baseline, six months, and 12 months. To compare BLLs, we identified a matched comparison group. We enrolled and randomized 314 newborns in the intervention component; 110 completed the study. There were few significant differences between the randomized groups. In the combined intervention groups, positive results on visual inspection declined from baseline to 12 months (97.0% to 90.6%, p = 0.007). At baseline, 36.9% of homes were above the U.S. Environmental Protection Agency's lead dust standard, compared with 26.9% at 12 months (p = 0.032), mainly due to a drop in windowsill dust levels. Both groups showed a significant increase in parental scores on a lead education test. Children in the intervention and matched control groups had similar geometric mean initial BLLs (2.6 vs. 2.7, p = 0.477), but a significantly higher percentage of children in the intervention group had an initial blood lead screening compared with those in the matched group (88.9% vs. 84.4%, p = 0.032). A study of primary prevention of lead exposure showed a higher blood lead screening rate for the combined intervention groups and mean BLLs at one year of age not statistically different from the comparison group. Most homes had lead hazards. Lead education significantly increased knowledge.

Exposure to lead affects male biothiols metabolism.

PubMed

Kasperczyk, Sławomir; Błaszczyk, Iwona; Dobrakowski, Michał; Romuk, Ewa; Kapka-Skrzypczak, Lucyna; Adamek, Mariusz; Birkner, Ewa

2013-01-01

The most important biothiols include glutathione, homocysteine (HCY), cysteine and proteins. The aim of the presented study was to evaluate the influence of lead on the biothiol turnover--the concentration of HCY and protein sulfhydryl groups (P-SH) in the serum and reduced glutathione (G-SH) in erythrocytes--in individuals (employees of metal works) exposed to lead and to evaluate its probable oxidative disorders, measured as the carbonyl protein (CP) concentration in serum. The exposed workers were divided into 2 subgroups: 1) low lead exposure (LPb), with a lead concentration in the blood (PbB) of 20-45 µg dl(-1) (n= 102), and 2) high lead exposure (HPb), with PbB = 45-60 µg dl(-1) (n= 81). The control group consisted of 72 office workers or other healthy subjects with no history of occupational exposure to lead. All the controls had normal PbB (<10 μg dl(-1)) and ZPP (<2.5 μg dl(-1)) levels. The concentration of HCY was higher in the LPb group by 11% and in the HPb group by 26%, compared with the control group (n=72). The CP concentration in these 2 groups was more than twice as high as that of the control group, with 108% and 125% increases for the LPb and HPb groups, respectively; G-SH was lower by 6.6% and 7.4% for the LPb and HPb groups, respectively; P-SH was lower by 8.2% and 13% for the LPb and HPb groups, respectively. Lead decreases levels of glutathione and protein thiol groups. Lead-induced oxidative stress contributes to the observed elevation of protein carbonyl groups. Besides, lead poisoning seems to be associated with hyperhomocysteinaemia, which may promote the development of atherosclerosis.

Consumption of fruits and vegetables and probabilistic assessment of the cumulative acute exposure to organophosphorus and carbamate pesticides of schoolchildren in Slovenia.

PubMed

Blaznik, Urška; Yngve, Agneta; Eržen, Ivan; Hlastan Ribič, Cirila

2016-02-01

Adequate consumption of fruits and vegetables is a part of recommendations for a healthy diet. The aim of the present study was to assess acute cumulative dietary exposure to organophosphorus and carbamate pesticides via fruit and vegetable consumption by the population of schoolchildren aged 11-12 years and the level of risk for their health. Cumulative probabilistic risk assessment methodology with the index compound approach was applied. Slovenia, primary schools. Schoolchildren (n 1145) from thirty-one primary schools in Slovenia. Children were part of the PRO GREENS study 2009/10 which assessed 11-year-olds' consumption of fruit and vegetables in ten European countries. The cumulative acute exposure amounted to 8.3 (95% CI 7.7, 10.6) % of the acute reference dose (ARfD) for acephate as index compound (100 µg/kg body weight per d) at the 99.9th percentile for daily intake and to 4.5 (95% CI 3.5, 4.7) % of the ARfD at the 99.9th percentile for intakes during school time and at lunch. Apples, bananas, oranges and lettuce contributed most to the total acute pesticides intake. The estimations showed that acute dietary exposure to organophosphorus and carbamate pesticides is not a health concern for schoolchildren with the assessed dietary patterns of fruit and vegetable consumption.

Environmental exposures to lead and cadmium measured in human placenta.

PubMed

Falcón, María; Viñas, Pilar; Osuna, Eduardo; Luna, Aurelio

2002-01-01

Pregnant women exposed to even low levels of environmental lead and cadmium may experience adverse perinatal effects. To evaluate the usefulness of the placenta for monitoring environmental lead and cadmium exposure, concentrations of both metals were measured in placentas (n = 86) with atomic absorption spectrometry. Environmental exposure was assessed in accordance with the degree of industrial activity and transport pollution near the places of residence. The authors found significantly higher lead and cadmium levels in placentas of women living in urban-industrial areas than in placentas of women living in rural areas. Lead concentrations in placenta reflect environmental exposures; smoking during gestation explained a large portion of placental cadmium. This finding suggests that when a pregnant woman is a heavy smoker, tobacco exposure masks environmental cadmium exposure, especially in areas with low levels of cadmium pollution.

Lead Exposure in Military Outdoor Firing Ranges.

PubMed

Greenberg, Nili; Frimer, Ron; Meyer, Robert; Derazne, Estella; Chodick, Gabrial

2016-09-01

Several studies have reported significant airborne lead exposures during training at indoor firing ranges. Scarce attention has been given to airborne lead exposures in outdoor shooting ranges with automatic weapons. To assess the prevalence and magnitude of airborne and blood lead levels (BLL) among firing instructors and shooters in military outdoor ranges. Exposure assessment, for both trainees and instructors, included airborne and BLL during basic and advanced training at outdoor firing ranges. Personal airborne samples were collected in both day and night shooting during both training periods. During basic training, there is 95% likelihood that up to 25% of instructors and 99% likelihood that up to 5% of trainees might be exposed above the action level (AL) (25 μg/m(3)). During advanced training, there is 90% likelihood that 10% of instructors and 99% likelihood that up to 10% of trainees might be exposed above the AL. Military personnel participating in automatic weapon marksmanship training can be exposed to considerable levels of airborne lead during outdoor firing range training. As a result, the Israel Defense Force Medical Corp has classified firing range instructors as workers that require periodic medical examinations. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Urban gardens: lead exposure, recontamination mechanisms, and implications for remediation design.

PubMed

Clark, Heather F; Hausladen, Debra M; Brabander, Daniel J

2008-07-01

Environmental lead contamination is prevalent in urban areas where soil represents a significant sink and pathway of exposure. This study characterizes the speciation of lead that is relevant to local recontamination and to human exposure in the backyard gardens of Roxbury and Dorchester, MA, USA. One hundred forty-one backyard gardens were tested by X-ray fluorescence, and 81% of gardens have lead levels above the US EPA action limit of 400 microg/g. Raised gardening beds are the in situ exposure reduction method used in the communities to promote urban gardening. Raised beds were tested for lead and the results showed that the lead concentration increased from an initial range of 150+/-40 microg/g to an average of 336 microg/g over 4 years. The percent distribution of lead in the fine grain soil (<100 microm) and the trace metal signature of the raised beds support the conclusion that the mechanism of recontamination is wind-transported particles. Scanning electron microscopy and sequential extraction were used to characterize the speciation of lead, and the trace metal signature of the fine grain soil in both gardens and raised gardening beds is characteristic of lead-based paint. This study demonstrates that raised beds are a limited exposure reduction method and require maintenance to achieve exposure reduction goals. An exposure model was developed based on a suite of parameters that combine relevant values from the literature with site-specific quantification of exposure pathways. This model suggests that consumption of homegrown produce accounts for only 3% of children's daily exposure of lead while ingestion of fine grained soil (<100 microm) accounts for 82% of the daily exposure. This study indicates that urban lead remediation on a yard-by-yard scale requires constant maintenance and that remediation may need to occur on a neighborhood-wide scale.

Lead exposure in Mexican radiator repair workers.

PubMed

Dykeman, Ronald; Aguilar-Madrid, Guadalupe; Smith, Tom; Juárez-Pérez, Cuauhtemoc Arturo; Piacitelli, Gregory M; Hu, Howard; Hernandez-Avila, Mauricio

2002-03-01

Lead exposure was investigated among 73 Mexican radiator repair workers (RRWs), 12 members of their family (4 children and 8 wives), and 36 working controls. RRWs were employed at 4 radiator repair shops in Mexico City and 27 shops in Cuernavaca and surrounding areas. Exposure was assessed directly through the use of personal air sampling and hand wipe samples. In addition, industrial hygiene inspections were performed and detailed questionnaires were administered. Blood lead levels were measured by graphite furnace atomic absorption spectroscopy (AAS). The mean (SD) values for blood lead of the RRWs, 35.5 (13.5) microg/dl, was significantly greater than the same values for the working controls, 13.6 (8.7) microg/dl; P < 001. After excluding a single outlier (247 microg/m(3)), air lead levels ranged from 0 to 99 microg/m(3) with a mean (SD) value of 19 (23) microg/m(3) (median = 7.9 microg/m(3)). In a final multivariate regression model of elevated blood lead levels, the strongest predictors were smoking (vs. non-smoking), the number of radiators repaired per day on average, and the use (vs. non-use) of a uniform while at work, which were associated with blood lead elevations of 11.4 microg/dl, 1.95 microg/dl/radiator/day, and 16.4 microg/dl, respectively (all P <.05). Uniform use was probably a risk factor because they were not laundered regularly and consequently served as reservoir of contamination on which RRWs frequently wiped their hands. Lead exposure is a significant problem of radiator repair work, a small industry that is abundant in Mexico and other developing countries. Copyright 2002 Wiley-Liss, Inc.

Primary Prevention of Lead Exposure: The Philadelphia Lead Safe Homes Study

PubMed Central

Campbell, Carla; Tran, Mary; Gracely, Edward; Starkey, Naomi; Kersten, Hans; Palermo, Peter; Rothman, Nancy; Line, Laura; Hansen-Turton, Tine

2011-01-01

Objective Lead exposure in children can lead to neuropsychological impairment. This study tested whether primary prevention interventions in the newborn period prevent elevated blood lead levels (BLLs). Methods The Philadelphia Lead Safe Homes (LSH) Study offered parental education, home evaluation, and lead remediation to the families of urban newborns. Households were randomized to a standard lead education group or maintenance education group. We conducted home visits at baseline, six months, and 12 months. To compare BLLs, we identified a matched comparison group. Results We enrolled and randomized 314 newborns in the intervention component; 110 completed the study. There were few significant differences between the randomized groups. In the combined intervention groups, positive results on visual inspection declined from baseline to 12 months (97.0% to 90.6%, p=0.007). At baseline, 36.9% of homes were above the U.S. Environmental Protection Agency's lead dust standard, compared with 26.9% at 12 months (p=0.032), mainly due to a drop in windowsill dust levels. Both groups showed a significant increase in parental scores on a lead education test. Children in the intervention and matched control groups had similar geometric mean initial BLLs (2.6 vs. 2.7, p=0.477), but a significantly higher percentage of children in the intervention group had an initial blood lead screening compared with those in the matched group (88.9% vs. 84.4%, p=0.032). Conclusions A study of primary prevention of lead exposure showed a higher blood lead screening rate for the combined intervention groups and mean BLLs at one year of age not statistically different from the comparison group. Most homes had lead hazards. Lead education significantly increased knowledge. PMID:21563715

Neurotoxic effects and biomarkers of lead exposure: a review.

PubMed

Sanders, Talia; Liu, Yiming; Buchner, Virginia; Tchounwou, Paul B

2009-01-01

Lead, a systemic toxicant affecting virtually every organ system, primarily affects the central nervous system, particularly the developing brain. Consequently, children are at a greater risk than adults of suffering from the neurotoxic effects of lead. To date, no safe lead-exposure threshold has been identified. The ability of lead to pass through the blood-brain barrier is due in large part to its ability to substitute for calcium ions. Within the brain, lead-induced damage in the prefrontal cerebral cortex, hippocampus, and cerebellum can lead to a variety of neurologic disorders. At the molecular level, lead interferes with the regulatory action of calcium on cell functions and disrupts many intracellular biological activities. Experimental studies have also shown that lead exposure may have genotoxic effects, especially in the brain, bone marrow, liver, and lung cells. Knowledge of the neurotoxicology of lead has advanced in recent decades due to new information on its toxic mechanisms and cellular specificity. This paper presents an overview, updated to January 2009, of the neurotoxic effects of lead with regard to children, adults, and experimental animals at both cellular and molecular levels, and discusses the biomarkers of lead exposure that are useful for risk assessment in the field of environmental health.

Environmental lead exposure: a public health problem of global dimensions.

PubMed Central

Tong, S.; von Schirnding, Y. E.; Prapamontol, T.

2000-01-01

Lead is the most abundant of the heavy metals in the Earth's crust. It has been used since prehistoric times, and has become widely distributed and mobilized in the environment. Exposure to and uptake of this non-essential element have consequently increased. Both occupational and environmental exposures to lead remain a serious problem in many developing and industrializing countries, as well as in some developed countries. In most developed countries, however, introduction of lead into the human environment has decreased in recent years, largely due to public health campaigns and a decline in its commercial usage, particularly in petrol. Acute lead poisoning has become rare in such countries, but chronic exposure to low levels of the metal is still a public health issue, especially among some minorities and socioeconomically disadvantaged groups. In developing countries, awareness of the public health impact of exposure to lead is growing but relatively few of these countries have introduced policies and regulations for significantly combating the problem. This article reviews the nature and importance of environmental exposure to lead in developing and developed countries, outlining past actions, and indicating requirements for future policy responses and interventions. PMID:11019456

Impact of the California lead ammunition ban on reducing lead exposure in golden eagles and turkey vultures.

PubMed

Kelly, Terra R; Bloom, Peter H; Torres, Steve G; Hernandez, Yvette Z; Poppenga, Robert H; Boyce, Walter M; Johnson, Christine K

2011-04-06

Predatory and scavenging birds may be exposed to high levels of lead when they ingest shot or bullet fragments embedded in the tissues of animals injured or killed with lead ammunition. Lead poisoning was a contributing factor in the decline of the endangered California condor population in the 1980s, and remains one of the primary factors threatening species recovery. In response to this threat, a ban on the use of lead ammunition for most hunting activities in the range of the condor in California was implemented in 2008. Monitoring of lead exposure in predatory and scavenging birds is essential for assessing the effectiveness of the lead ammunition ban in reducing lead exposure in these species. In this study, we assessed the effectiveness of the regulation in decreasing blood lead concentration in two avian sentinels, golden eagles and turkey vultures, within the condor range in California. We compared blood lead concentration in golden eagles and turkey vultures prior to the lead ammunition ban and one year following implementation of the ban. Lead exposure in both golden eagles and turkey vultures declined significantly post-ban. Our findings provide evidence that hunter compliance with lead ammunition regulations was sufficient to reduce lead exposure in predatory and scavenging birds at our study sites.

Impact of the California Lead Ammunition Ban on Reducing Lead Exposure in Golden Eagles and Turkey Vultures

PubMed Central

Kelly, Terra R.; Bloom, Peter H.; Torres, Steve G.; Hernandez, Yvette Z.; Poppenga, Robert H.; Boyce, Walter M.; Johnson, Christine K.

2011-01-01

Predatory and scavenging birds may be exposed to high levels of lead when they ingest shot or bullet fragments embedded in the tissues of animals injured or killed with lead ammunition. Lead poisoning was a contributing factor in the decline of the endangered California condor population in the 1980s, and remains one of the primary factors threatening species recovery. In response to this threat, a ban on the use of lead ammunition for most hunting activities in the range of the condor in California was implemented in 2008. Monitoring of lead exposure in predatory and scavenging birds is essential for assessing the effectiveness of the lead ammunition ban in reducing lead exposure in these species. In this study, we assessed the effectiveness of the regulation in decreasing blood lead concentration in two avian sentinels, golden eagles and turkey vultures, within the condor range in California. We compared blood lead concentration in golden eagles and turkey vultures prior to the lead ammunition ban and one year following implementation of the ban. Lead exposure in both golden eagles and turkey vultures declined significantly post-ban. Our findings provide evidence that hunter compliance with lead ammunition regulations was sufficient to reduce lead exposure in predatory and scavenging birds at our study sites. PMID:21494329

Childhood lead exposure in France: benefit estimation and partial cost-benefit analysis of lead hazard control

PubMed Central

2011-01-01

Background Lead exposure remains a public health concern due to its serious adverse effects, such as cognitive and behavioral impairment: children younger than six years of age being the most vulnerable population. In Europe, the lead-related economic impacts have not been examined in detail. We estimate the annual costs in France due to childhood exposure and, through a cost benefit analysis (CBA), aim to assess the expected social and economic benefits of exposure abatement. Methods Monetary benefits were assessed in terms of avoided national costs. We used results from a 2008 survey on blood-lead (B-Pb) concentrations in French children aged one to six years old. Given the absence of a threshold concentration being established, we performed a sensitivity analysis assuming different hypothetical threshold values for toxicity above 15 μg/L, 24 μg/L and 100 μg/L. Adverse health outcomes of lead exposure were translated into social burden and economic costs based on literature data from literature. Direct health benefits, social benefits and intangible avoided costs were included. Costs of pollutant exposure control were partially estimated in regard to homes lead-based paint decontamination, investments aiming at reducing industrial lead emissions and removal of all lead drinking water pipes. Results The following overall annual benefits for the three hypothetical thresholds values in 2008 are: €22.72 billion, €10.72 billion and €0.44 billion, respectively. Costs from abatement ranged from €0.9 billion to 2.95 billion/year. Finally, from a partial CBA of lead control in soils and dust the estimates of total net benefits were € 3.78 billion, € 1.88 billion and €0.25 billion respectively for the three hypothesized B-Pb effect values. Conclusions Prevention of childhood lead exposure has a high social benefit, due to reduction of B-Pb concentrations to levels below 15 μg/L or 24 μg/L, respectively. Reducing only exposures above 100 μg/L B-Pb has

Long-term human exposure to lead from different media and intake pathways.

PubMed

Pizzol, Massimo; Thomsen, Marianne; Andersen, Mikael Skou

2010-10-15

Lead (Pb) is well known as an environmental pollutant: it can accumulate in various media, so actual lead exposure reflects both historical and present contaminations. Two main challenges then emerge: obtaining updated information to gain an overall picture of the sources of exposure, and predicting the resulting internal body exposure levels and effects that occur under long-term exposure conditions. In this paper, a modeling approach is used to meet these challenges with reference to Danish exposure conditions. Levels of lead content in various media have been coupled with data for lead intake and absorption in the human body, for both children and adults. An age-dependent biokinetic model allows then for determination of the blood lead levels resulting from chronic exposure. The study shows that the actual intake of lead is up to 27% of the Provisional Tolerable Daily Intake (PTDI) for children and around 8% for adults. It is confirmed that the critical route of exposure is via ingestion, accounting for 99% of total lead intake, while inhalation contributes only to 1% of total lead intake. The resulting lead levels in the blood after 2 years of exposure to actual contamination conditions have been estimated as up to 2.2μg/dl in children and almost 1μg/dl in adults. Impacts from lead can occur even at such levels. The role of historical and present sources to lead in the environment is discussed, and, for specific child and adult exposure scenarios, external-internal concentration relationships for the direct linkage between lead in environmental media and resulting concentrations of lead in blood are then presented. Copyright © 2010 Elsevier B.V. All rights reserved.

Cumulative hazard: The case of nuisance flooding

NASA Astrophysics Data System (ADS)

Moftakhari, Hamed R.; AghaKouchak, Amir; Sanders, Brett F.; Matthew, Richard A.

2017-02-01

The cumulative cost of frequent events (e.g., nuisance floods) over time may exceed the costs of the extreme but infrequent events for which societies typically prepare. Here we analyze the likelihood of exceedances above mean higher high water and the corresponding property value exposure for minor, major, and extreme coastal floods. Our results suggest that, in response to sea level rise, nuisance flooding (NF) could generate property value exposure comparable to, or larger than, extreme events. Determining whether (and when) low cost, nuisance incidents aggregate into high cost impacts and deciding when to invest in preventive measures are among the most difficult decisions for policymakers. It would be unfortunate if efforts to protect societies from extreme events (e.g., 0.01 annual probability) left them exposed to a cumulative hazard with enormous costs. We propose a Cumulative Hazard Index (CHI) as a tool for framing the future cumulative impact of low cost incidents relative to infrequent extreme events. CHI suggests that in New York, NY, Washington, DC, Miami, FL, San Francisco, CA, and Seattle, WA, a careful consideration of socioeconomic impacts of NF for prioritization is crucial for sustainable coastal flood risk management.

DIETARY EXPOSURE OF CHILDREN IN LEAD-LADEN ENVIRONMENTS

EPA Science Inventory

Children are the most susceptible population to lead exposure because of three interacting factors; they have more opportunity for contact with lead sources due to their activities, lead absorption occurs more readily in a child compared to an adult, and the child's development i...

Prenatal lead exposure and childhood blood pressure and kidney function.

PubMed

Skröder, Helena; Hawkesworth, Sophie; Moore, Sophie E; Wagatsuma, Yukiko; Kippler, Maria; Vahter, Marie

2016-11-01

Exposure to lead, a common environmental pollutant, is known to cause cardiovascular and nephrotoxic effects in adults. Potential effects of early-life lead exposure on these functions are, however, less well characterized. To assess blood pressure and kidney function in preschool-aged children in relation to prenatal lead exposure. This prospective study in rural Bangladesh measured children's systolic and diastolic blood pressure in triplicate at the follow-up at 4.5±0.11 years. Their kidney function was assessed by the estimated glomerular filtration rate (eGFR), calculated based on serum cystatin C concentrations, and by kidney volume, measured by sonography. Exposure to lead was assessed by concentrations in the mothers' blood (erythrocyte fraction; Ery-Pb) in gestational weeks (GW) 14 and 30, the effects of which were evaluated separately in multivariable-adjusted linear regression analyses. We found no associations between maternal exposure to lead [n~1500 for GW14 and 700 for GW30] and children's blood pressure or eGFR. However, we found an inverse association between late gestation lead and kidney volume, although the sample size was limited (n=117), but not with early gestation lead (n=573). An increase of 85µg/kg in Ery-Pb (median concentration at GW30) was associated with a 6.0cm 3 /m 2 decrease in kidney volume (=0.4SD; p=0.041). After stratifying on gender, there seemed to be a somewhat stronger association in girls. Prenatal lead exposure may cause long-lasting effects on the kidney. This warrants follow-up studies in older children, as well as additional studies in other populations. Copyright © 2016. Published by Elsevier Inc.

Urban gardens: Lead exposure, recontamination mechanisms, and implications for remediation design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Heather F.; Hausladen, Debra M.; Brabander, Daniel J.

2008-07-15

Environmental lead contamination is prevalent in urban areas where soil represents a significant sink and pathway of exposure. This study characterizes the speciation of lead that is relevant to local recontamination and to human exposure in the backyard gardens of Roxbury and Dorchester, MA, USA. One hundred forty-one backyard gardens were tested by X-ray fluorescence, and 81% of gardens have lead levels above the US EPA action limit of 400 {mu}g/g. Raised gardening beds are the in situ exposure reduction method used in the communities to promote urban gardening. Raised beds were tested for lead and the results showed thatmore » the lead concentration increased from an initial range of 150{+-}40 {mu}g/g to an average of 336 {mu}g/g over 4 years. The percent distribution of lead in the fine grain soil (<100 {mu}m) and the trace metal signature of the raised beds support the conclusion that the mechanism of recontamination is wind-transported particles. Scanning electron microscopy and sequential extraction were used to characterize the speciation of lead, and the trace metal signature of the fine grain soil in both gardens and raised gardening beds is characteristic of lead-based paint. This study demonstrates that raised beds are a limited exposure reduction method and require maintenance to achieve exposure reduction goals. An exposure model was developed based on a suite of parameters that combine relevant values from the literature with site-specific quantification of exposure pathways. This model suggests that consumption of homegrown produce accounts for only 3% of children's daily exposure of lead while ingestion of fine grained soil (<100 {mu}m) accounts for 82% of the daily exposure. This study indicates that urban lead remediation on a yard-by-yard scale requires constant maintenance and that remediation may need to occur on a neighborhood-wide scale.« less

Silicosis among gold miners: exposure--response analyses and risk assessment.

PubMed

Steenland, K; Brown, D

1995-10-01

This study sought to estimate the risk of silicosis by cumulative exposure-years in a cohort of miners exposed to silica, as well as the lifetime risk of silicosis under the current Occupational Safety and Health Administration (OSHA) standard (0.09 mg/m3). In a cohort study of 3330 gold miners who worked at least 1 year underground from 1940 to 1965 (average 9 years) and were exposed to a median silica level of 0.05 mg/m3 (0.15 mg/m3 for those hired before 1930), 170 cases of silicosis were determined from either death certificates or two cross-sectional radiographic surveys. The risk of silicosis was less than 1% with a cumulative exposure under 0.5 mg/m3-years, increasing to 68% to 84% for the highest cumulative exposure category of more than 4 mg/m3-years. Cumulative exposure was the best predictor of disease, followed by duration of exposure and average exposure. After adjustment for competing risks of death, a 45-year exposure under the current OSHA standard would lead to a lifetime risk of silicosis of 35% to 47%. Almost 2 million US workers are currently exposed to silica. Our results add to a small but increasing body of literature that suggests that the current OSHA silica exposure level is unacceptably high.

Silicosis among gold miners: exposure--response analyses and risk assessment.

PubMed Central

Steenland, K; Brown, D

1995-01-01

OBJECTIVES. This study sought to estimate the risk of silicosis by cumulative exposure-years in a cohort of miners exposed to silica, as well as the lifetime risk of silicosis under the current Occupational Safety and Health Administration (OSHA) standard (0.09 mg/m3). METHODS. In a cohort study of 3330 gold miners who worked at least 1 year underground from 1940 to 1965 (average 9 years) and were exposed to a median silica level of 0.05 mg/m3 (0.15 mg/m3 for those hired before 1930), 170 cases of silicosis were determined from either death certificates or two cross-sectional radiographic surveys. RESULTS. The risk of silicosis was less than 1% with a cumulative exposure under 0.5 mg/m3-years, increasing to 68% to 84% for the highest cumulative exposure category of more than 4 mg/m3-years. Cumulative exposure was the best predictor of disease, followed by duration of exposure and average exposure. After adjustment for competing risks of death, a 45-year exposure under the current OSHA standard would lead to a lifetime risk of silicosis of 35% to 47%. CONCLUSIONS. Almost 2 million US workers are currently exposed to silica. Our results add to a small but increasing body of literature that suggests that the current OSHA silica exposure level is unacceptably high. PMID:7573620

Cumulative Exposure to Systolic Blood Pressure During Young Adulthood Through Midlife and the Urine Albumin-to-Creatinine Ratio at Midlife.

PubMed

Kramer, Holly; Colangelo, Laura; Lewis, Cora E; Jacobs, David R; Pletcher, Mark; Bibbins-Domingo, Kirstin; Chang, Alex; Siscovick, David; Shlipak, Michael; Peralta, Carmen A; Bansal, Nisha; Muntner, Paul; Liu, Kiang

2017-05-01

Higher blood pressure during young adulthood may increase cardiovascular and kidney disease risk later in life. This study examined the association of cumulative systolic blood pressure (SBP) exposure during young adulthood through midlife with urine albumin-to-creatinine ratios (ACR) measured during midlife. We used data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a biracial cohort recruited in 4 urban areas during years 1985-1986. Cumulative SBP was calculated as the average SBP between 2 exams multiplied by years between exams over 20 year years. ACR was measured 20 years after baseline when participants were age 43-50 years (midlife). A generalized additive model was used to examine the association of log ACR as a function of cumulative SBP with adjustment for covariates including SBP measured concurrently with ACR. Cumulative SBP ranged from a low of 1,671 to a high of 3,260 mm Hg. Participants in the highest cumulative SBP quartile were more likely to be male (61.4% vs. 20.7%; P < 0.001), Black (61.5% vs. 25.6%; P < 0.001) and have elevated ACR (18.7% vs. 4.8%; P < 0.001) vs. lowest quartile. Spline regression curves of ACR vs. cumulative SBP demonstrated an inflection point in ACR with cumulative SBP levels >2,350 mm Hg with linear increases in ACR above this threshold. Adjusted geometric mean ACR values were significantly higher with cumulative SBP ≥2,500 vs. <2500 (9.18 [1.06] vs. 6.92 [1.02]; P < 0.0001). Higher SBP during young adulthood through midlife is associated with higher ACR during midlife. © American Journal of Hypertension, Ltd 2017. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Lead exposure in Latin America and the Caribbean. Lead Research Group of the Pan-American Health Organization.

PubMed Central

Romieu, I; Lacasana, M; McConnell, R

1997-01-01

As a result of the rapid industrialization of Latin America and the Caribbean during the second half of this century, exposure to lead has become an increasingly important problem. To obtain an estimate of the magnitude of lead exposure in the region, we carried out a survey and a literature search on potential sources of lead exposure and on blood lead concentrations. Sixteen out of 18 Latin American and 2 out of 10 Caribbean countries responded to the survey. Lead in gasoline remains a major problem, although the lead content has decreased in many countries in the last few years. The impact of leaded fuel is more important in urban settings, given their high vehicular density. Seventy-five percent of the population of the region lives in urban areas, and children younger than 15 years of age, the most susceptible group, comprise 30% of the population. Other sources of lead exposure identified in the region included industrial emissions, battery recycling, paint and varnishes, and contaminated food and water. Lead is recognized as a priority problem by national authorities in 72% of the countries that responded to the survey, and in 50% of the countries some legislation exists to regulate the lead content in certain products. However, compliance is low. There is an urgent need for a broad-based coalition between policy makers, industry, workers, unions, health care providers, and the community to take actions to reduce environmental and occupational lead exposures in all the Latin American and Caribbean countries. Images Figure 1. Figure 2. PMID:9189704

Aggregate-level lead exposure, gun violence, homicide, and rape

PubMed Central

Nelson, Erik J.; Qian, Zhengmin; Vaughn, Michael G.; Wright, John P.; Beaver, Kevin M.; Barnes, J. C.; Petkovsek, Melissa; Lewis, Roger; Schootman, Mario; Rosenfeld, Richard

2017-01-01

Context An increasing body of research has linked the geographic distribution of lead with various indicators of criminal and antisocial behavior. Objective The current study, using data from an ongoing project related to lead exposure in St. Louis City, MO, analyzed the association between aggregate blood lead levels and specific indicators violent crime within the city. Design Ecological study. Setting St. Louis, Missouri. Exposure measure Blood lead levels. Main outcome measure Official reports of violent crimes were categorized as 1) crimes involving a firearm (yes/no), 2) assault crimes (with or without a firearm), 3) robbery crimes (with or without a firearm), 4) homicides and 5) rape. Results With the exception of rape, aggregate blood-lead levels were statistically significant predictors of violent crime at the census tract level. The risk ratios for each of the outcome measures were as follows: firearm crimes 1.03 (1.03–1.04), assault crimes 1.03 (1.02–1.03), robbery crimes 1.03 (1.02–1.04), homicide 1.03 (1.01, 1.04), and rape 1.01 (0.99–1.03). Conclusions Extending prior research in St. Louis, results suggest that aggregated lead exposure at the census tract level predicted crime outcomes, even after accounting for important sociological variables. Moving forward, a more developed understanding of aggregate level crime may necessitate a shift toward studying the synergy between sociological and biological risk factors such as lead exposure. PMID:29176826

Risk assessment of the cumulative acute exposure of Hungarian population to organophosphorus pesticide residues with regard to consumers of plant based foods.

PubMed

Zentai, Andrea; Szabó, István J; Kerekes, Kata; Ambrus, Árpád

2016-03-01

Based on the Hungarian pesticide residues monitoring data of the last five years and the consumption data collected within a 3-day dietary record survey in 2009 (more than 2 million pesticide residue results and almost 5000, 0-101-year-old consumers 3 non-consecutive-day personal fruit and vegetable consumption data), the cumulative acute exposure of organophosphorus pesticide residues was evaluated. The relative potency factor approach was applied, with acephate chosen as index compound. According to our conservative calculation method, applying the measured residues only, the 99.95% of the 99th percentiles of calculated daily intakes was at or below 87 μg/kgbwday, indicating that the cumulative acute exposure of the whole Hungarian population (including all age classes) to organophosphorus compounds was not a health concern. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cumulants, free cumulants and half-shuffles

PubMed Central

Ebrahimi-Fard, Kurusch; Patras, Frédéric

2015-01-01

Free cumulants were introduced as the proper analogue of classical cumulants in the theory of free probability. There is a mix of similarities and differences, when one considers the two families of cumulants. Whereas the combinatorics of classical cumulants is well expressed in terms of set partitions, that of free cumulants is described and often introduced in terms of non-crossing set partitions. The formal series approach to classical and free cumulants also largely differs. The purpose of this study is to put forward a different approach to these phenomena. Namely, we show that cumulants, whether classical or free, can be understood in terms of the algebra and combinatorics underlying commutative as well as non-commutative (half-)shuffles and (half-) unshuffles. As a corollary, cumulants and free cumulants can be characterized through linear fixed point equations. We study the exponential solutions of these linear fixed point equations, which display well the commutative, respectively non-commutative, character of classical and free cumulants. PMID:27547078

Lead and ethanol co-exposure lead to blood oxidative stress and subsequent neuronal apoptosis in rats.

PubMed

Flora, Swaran J S; Gautam, Pratibha; Kushwaha, Pramod

2012-01-01

The present study was aimed at investigating chronic exposure to lead and ethanol, individually and in combination with blood oxidative stress leading to possible brain apoptosis in rats. Rats were exposed to lead (0.1% w/v in drinking water) or ethanol (1 and 10%) either individually or in combination for four months. Biochemical variables indicative of oxidative stress (blood and brain) and brain apoptosis were examined. Native polyacrylamide agarose gel electrophoresis was carried out in brain homogenates for glucose-6-phosphate dehydrogenase (G6PD) analysis, whereas western blot analysis was done for the determination of apoptotic markers like Bax, Bcl-2, caspase-3, cytochrome c and p53. The results suggest that most pronounced increase in oxidative stress in red blood cells and brain of animals co-exposed to lead and 10% ethanol compared all the other groups. Decrease in G6PD activity followed the same trend. Upregulation of Bax, cytochrome c, caspase-3, p53 and down-regulation of Bcl-2 suggested apoptosis in the rat brain co-exposed to lead and ethanol (10%) compared with their individual exposures. Significantly high lead accumulation in blood and brain during co-exposure further support synergistic toxicity. The present study thus suggests that higher consumption of ethanol during lead exposure may lead to brain apoptosis, which may be mediated through oxidative stress.

Multimedia lead exposure and associated risk assessment in Dhaka, Bangladesh

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarwar, M.

1998-12-31

Motor vehicles consume the largest amount of leaded gasoline in Bangladesh. The number of vehicles and fuel consumption have increased significantly in recent years. These vehicles, which are believed to be the major sources of lead emissions in Dhaka, may cause an excessive level of lead exposure in children. The paper describes the results of a study conducted to determine risk associated with the multimedia lead exposure for children in Dhaka. Specifically, data related to lead content in air and soil in Dhaka were collected and used to estimate the blood lead levels in children. The Integrated Exposure Uptake Biokineticsmore » Model, developed by the United States Environmental Protection Agency (USEPA), was used. Bangladesh is yet to adopt any blood lead standards. The results of the study indicated that the model predicted geometric blood lead levels in children in Dhaka are significantly below the blood lead standard recommended by the World Health Organization (WHO). It was also found that children in Dhaka are not expected to contain blood lead levels higher than the WHO recommended standard.« less

Cumulative Injury

PubMed Central

LaDou, Joseph

1978-01-01

A few states, notably California, are experiencing large increases in the number and cost of disability settlements under workers' compensation. Claims of cumulative injury for coronary heart disease, hypertension, stroke, cancer and neuropsychiatric problems have all been interpreted as compensable under workers' compensation, even when these conditions are clearly related to the aging process. Legal precedents for such claims are building rapidly throughout the country. The resultant costs may lead to the demise of the workers' compensation system. The situation in California is discussed in detail including the legal aspects, cumulative injury claims by type of disease and age of claimants, legal costs to the individual and the employer, and the economic outlook for the workers' compensation insurance system. PMID:151986

Electric kettles as a source of human lead exposure.

PubMed

Wigle, D T; Charlebois, E J

1978-01-01

Five hundred and seventy-four households in Ottawa were surveyed to evaluate water boiled in electric kettles as a source of lead exposure. Samples of boiled water exceeded the World Health Organization mandatory limit for drinking water (50 microgram/l) in 42.5% of the households. Excessive lead concentrations were observed in 62.8% of water samples from kettles more than 5 years old. Multiple regression analysis indicated that age, sex, and cigarette smoking habits, but not lead concentration in boiled water, nor weekly consumption of boiled water were significantly associated with blood-lead concentration. Lead exposure from electric kettles may be a significant problem only in infants receiving formula prepared with boiled water.

Neurodevelopment in Early Childhood Affected by Prenatal Lead Exposure and Iron Intake.

PubMed

Shah-Kulkarni, Surabhi; Ha, Mina; Kim, Byung-Mi; Kim, Eunjeong; Hong, Yun-Chul; Park, Hyesook; Kim, Yangho; Kim, Bung-Nyun; Chang, Namsoo; Oh, Se-Young; Kim, Young Ju; Kimʼs, Young Ju; Lee, Boeun; Ha, Eun-Hee

2016-01-01

No safe threshold level of lead exposure in children has been recognized. Also, the information on shielding effect of maternal dietary iron intake during pregnancy on the adverse effects of prenatal lead exposure on children's postnatal neurocognitive development is very limited. We examined the association of prenatal lead exposure and neurodevelopment in children at 6, 12, 24, and 36 months and the protective action of maternal dietary iron intake against the impact of lead exposure. The study participants comprise 965 pregnant women and their subsequent offspring of the total participants enrolled in the Mothers and Children's environmental health study: a prospective birth cohort study. Generalized linear model and linear mixed model analysis were performed to analyze the effect of prenatal lead exposure and mother's dietary iron intake on children's cognitive development at 6, 12, 24, and 36 months. Maternal late pregnancy lead was marginally associated with deficits in mental development index (MDI) of children at 6 months. Mothers having less than 75th percentile of dietary iron intake during pregnancy showed significant increase in the harmful effect of late pregnancy lead exposure on MDI at 6 months. Linear mixed model analyses showed the significant detrimental effect of prenatal lead exposure in late pregnancy on cognitive development up to 36 months in children of mothers having less dietary iron intake during pregnancy. Thus, our findings imply importance to reduce prenatal lead exposure and have adequate iron intake for better neurodevelopment in children.

Neurodevelopment in Early Childhood Affected by Prenatal Lead Exposure and Iron Intake

PubMed Central

Shah-Kulkarni, Surabhi; Ha, Mina; Kim, Byung-Mi; Kim, Eunjeong; Hong, Yun-Chul; Park, Hyesook; Kim, Yangho; Kim, Bung-Nyun; Chang, Namsoo; Oh, Se-Young; Kim, Young Ju; Lee, Boeun; Ha, Eun-Hee

2016-01-01

Abstract No safe threshold level of lead exposure in children has been recognized. Also, the information on shielding effect of maternal dietary iron intake during pregnancy on the adverse effects of prenatal lead exposure on children's postnatal neurocognitive development is very limited. We examined the association of prenatal lead exposure and neurodevelopment in children at 6, 12, 24, and 36 months and the protective action of maternal dietary iron intake against the impact of lead exposure. The study participants comprise 965 pregnant women and their subsequent offspring of the total participants enrolled in the Mothers and Children's environmental health study: a prospective birth cohort study. Generalized linear model and linear mixed model analysis were performed to analyze the effect of prenatal lead exposure and mother's dietary iron intake on children's cognitive development at 6, 12, 24, and 36 months. Maternal late pregnancy lead was marginally associated with deficits in mental development index (MDI) of children at 6 months. Mothers having less than 75th percentile of dietary iron intake during pregnancy showed significant increase in the harmful effect of late pregnancy lead exposure on MDI at 6 months. Linear mixed model analyses showed the significant detrimental effect of prenatal lead exposure in late pregnancy on cognitive development up to 36 months in children of mothers having less dietary iron intake during pregnancy. Thus, our findings imply importance to reduce prenatal lead exposure and have adequate iron intake for better neurodevelopment in children. PMID:26825887

Lack of observed movement response to lead exposure of California condors

USGS Publications Warehouse

Poessel, Sharon; Brandt, Joseph; Uyeda, Linda; Astell, Molly; Katzner, Todd E.

2018-01-01

Lead poisoning is an important conservation concern for wildlife, and scavenging birds are especially at risk from consumption of carcasses of animals killed with lead ammunition. Because current methods to identify lead exposure require animal capture and blood collection, management would benefit from the development of a less costly and noninvasive behavioral test for illness in wild animals. We attempted to design such a test to identify lead exposure in California condors (Gymnogyps californianus) that we tracked with global positioning system (GPS) telemetry in southern California, USA, 2013–2016. We measured blood-lead concentrations in tracked birds and expected that flight behavior would be influenced by lead exposure; thus, we measured the effect of blood-lead concentrations on 2 different types of movement rates and on the proportion of time condors spent in flight. We found no effect of lead exposure on any of these 3 behavioral metrics. Our work suggests that the measurements we took of flight behaviors were not a useful tool in predicting lead exposure in the mildly to moderately exposed birds we studied. Wild birds are effective at hiding illness, especially condors who have a strong social hierarchy in which showing weakness is a disadvantage. However, focusing on behaviors other than flight, expanding the sample studied to include birds with a wider range of lead concentration values, or analyzing tissues such as feathers (rather than, or in addition to, blood) may be more useful for identification of lead exposure and other diseases that may limit wildlife populations. © 2017 This article is a U.S. Government work and is in the public domain in the USA.

Lead exposure and radiator repair work.

PubMed Central

Lussenhop, D H; Parker, D L; Barklind, A; McJilton, C

1989-01-01

In 1986, the ambient air for lead in radiator repair shops in the Minneapolis-St. Paul metropolitan area exceeded the Occupational Safety and Health Administration (OSHA) action level in nine of 12 shops sampled by Minnesota OSHA. We therefore sought to determine the prevalence of lead exposure/toxicity in this industry. Thirty-five radiator shops were identified, 30 were visited, and 53 workers were studied. The mean blood lead level was 1.53 (range 0.24-2.80). Seventeen individuals had blood lead levels greater than or equal to 1.93 mumol/L (40 micrograms/dl). The mean zinc protoporphyrin level (ZPP) was 0.55 mumol/L (range 0.16-1.43). No single worksite or personal characteristic was a strong determinant of either blood lead or ZPP level. PMID:2817174

Lead exposure and radiator repair work.

PubMed

Lussenhop, D H; Parker, D L; Barklind, A; McJilton, C

1989-11-01

In 1986, the ambient air for lead in radiator repair shops in the Minneapolis-St. Paul metropolitan area exceeded the Occupational Safety and Health Administration (OSHA) action level in nine of 12 shops sampled by Minnesota OSHA. We therefore sought to determine the prevalence of lead exposure/toxicity in this industry. Thirty-five radiator shops were identified, 30 were visited, and 53 workers were studied. The mean blood lead level was 1.53 (range 0.24-2.80). Seventeen individuals had blood lead levels greater than or equal to 1.93 mumol/L (40 micrograms/dl). The mean zinc protoporphyrin level (ZPP) was 0.55 mumol/L (range 0.16-1.43). No single worksite or personal characteristic was a strong determinant of either blood lead or ZPP level.

Concepts, Methods, and Data Sources for Cumulative Health Risk Assessment of Multiple Chemicals, Exposures and Effects: A Resource Document (Final Report, 2008)

EPA Science Inventory

EPA announced the availability of the final report, Concepts, Methods, and Data Sources for Cumulative Health Risk Assessment of Multiple Chemicals, Exposures and Effects: A Resource Document. This report provides the concepts, methods and data sources needed to assist in...

Glazed clay pottery and lead exposure in Mexico: Current experimental evidence.

PubMed

Diaz-Ruiz, Araceli; Tristán-López, Luis Antonio; Medrano-Gómez, Karen Itzel; Torres-Domínguez, Juan Alejandro; Ríos, Camilo; Montes, Sergio

2017-11-01

Lead exposure remains a significant environmental problem; lead is neurotoxic, especially in developing humans. In Mexico, lead in human blood is still a concern. Historically, much of the lead exposure is attributed to the use of handcrafted clay pottery for cooking, storing and serving food. However, experimental cause-and-effect demonstration is lacking. The present study explores this issue with a prospective experimental approach. We used handcrafted clay containers to prepare and store lemonade, which was supplied as drinking water to pregnant rats throughout the gestational period. We found that clay pots, jars, and mugs leached on average 200 µg/l lead, and exposure to the lemonade resulted in 2.5 µg/dl of lead in the pregnant rats' blood. Neonates also showed increased lead content in the hippocampus and cerebellum. Caspase-3 activity was found to be statistically increased in the hippocampus in prenatally exposed neonates, suggesting increased apoptosis in that brain region. Glazed ceramics are still an important source of lead exposure in Mexico, and our results confirm that pregnancy is a vulnerable period for brain development.

Effects of lead exposure before pregnancy and dietary calcium during pregnancy on fetal development and lead accumulation.

PubMed Central

Han, S; Pfizenmaier, D H; Garcia, E; Eguez, M L; Ling, M; Kemp, F W; Bogden, J D

2000-01-01

Millions of women of child-bearing age have substantial bone lead stores due to lead exposure as children. Dietary calcium ingested simultaneously with lead exposure can reduce lead absorption and accumulation. However, the effects of dietary calcium on previously accumulated maternal lead stores and transfer to the fetus have not been investigated. We studied the effects of lead exposure of female rats at an early age on fetal development during a subsequent pregnancy. We gave 5-week-old female Sprague-Dawley rats lead as the acetate in their drinking water for 5 weeks; controls received equimolar sodium acetate. This was followed by a 1-month period without lead exposure before mating. We randomly assigned pregnant rats (n = 39) to diets with a deficient (0.1%) or normal (0.5%) calcium content during pregnancy. A total of 345 pups were delivered alive. Lead-exposed dams and their pups had significantly higher blood lead concentrations than controls, but the concentrations were in the range of those found in many pregnant women. Pups born to dams fed the calcium-deficient diet during pregnancy had higher blood and organ lead concentrations than pups born to dams fed the 0. 5% calcium diet. Pups born to lead-exposed dams had significantly (p<0.0001) lower mean birth weights and birth lengths than controls. There were significant inverse univariate associations between dam or pup organ lead concentrations and birth weight or length. The 0.5% calcium diet did not increase in utero growth. Stepwise regression analysis demonstrated that greater litter size and female sex were significantly associated with reduced pup birth weight and length. However, lead exposure that ended well before pregnancy was significantly (p<0.0001) associated with reduced birth weight and length, even after litter size, pup sex, and dam weight gain during pregnancy were included in the regression analysis. The data demonstrate that an increase in dietary calcium during pregnancy can reduce

Exploring childhood lead exposure through GIS: a review of the recent literature.

PubMed

Akkus, Cem; Ozdenerol, Esra

2014-06-18

Childhood exposure to lead remains a critical health control problem in the US. Integration of Geographic Information Systems (GIS) into childhood lead exposure studies significantly enhanced identifying lead hazards in the environment and determining at risk children. Research indicates that the toxic threshold for lead exposure was updated three times in the last four decades: 60 to 30 micrograms per deciliter (µg/dL) in 1975, 25 µg/dL in 1985, and 10 µb/dL in 1991. These changes revealed the extent of lead poisoning. By 2012 it was evident that no safe blood lead threshold for the adverse effects of lead on children had been identified and the Center for Disease Control (CDC) currently uses a reference value of 5 µg/dL. Review of the recent literature on GIS-based studies suggests that numerous environmental risk factors might be critical for lead exposure. New GIS-based studies are used in surveillance data management, risk analysis, lead exposure visualization, and community intervention strategies where geographically-targeted, specific intervention measures are taken.

Exploring Childhood Lead Exposure through GIS: A Review of the Recent Literature

PubMed Central

Akkus, Cem; Ozdenerol, Esra

2014-01-01

Childhood exposure to lead remains a critical health control problem in the US. Integration of Geographic Information Systems (GIS) into childhood lead exposure studies significantly enhanced identifying lead hazards in the environment and determining at risk children. Research indicates that the toxic threshold for lead exposure was updated three times in the last four decades: 60 to 30 micrograms per deciliter (µg/dL) in 1975, 25 µg/dL in 1985, and 10 µb/dL in 1991. These changes revealed the extent of lead poisoning. By 2012 it was evident that no safe blood lead threshold for the adverse effects of lead on children had been identified and the Center for Disease Control (CDC) currently uses a reference value of 5 µg/dL. Review of the recent literature on GIS-based studies suggests that numerous environmental risk factors might be critical for lead exposure. New GIS-based studies are used in surveillance data management, risk analysis, lead exposure visualization, and community intervention strategies where geographically-targeted, specific intervention measures are taken. PMID:24945189

Atmospheric Teleconnections From Cumulants

NASA Astrophysics Data System (ADS)

Sabou, F.; Kaspi, Y.; Marston, B.; Schneider, T.

2011-12-01

Multi-point cumulants of fields such as vorticity provide a way to visualize atmospheric teleconnections, complementing other approaches such as the method of empirical orthogonal functions (EOFs). We calculate equal-time two-point cumulants of the vorticity from NCEP reanalysis data during the period 1980 -- 2010 and from direct numerical simulation (DNS) using an idealized dry general circulation model (GCM) (Schneider and Walker, 2006). Extratropical correlations seen in the NCEP data are qualitatively reproduced by the model. Three- and four-point cumulants accumulated from DNS quantify departures of the probability distribution function from a normal distribution, shedding light on the efficacy of direct statistical simulation (DSS) of atmosphere dynamics by cumulant expansions (Marston, Conover, and Schneider, 2008; Marston 2011). Lagged-time two-point cumulants between temperature gradients and eddy kinetic energy (EKE), accumulated by DNS of an idealized moist aquaplanet GCM (O'Gorman and Schneider, 2008), reveal dynamics of storm tracks. Regions of enhanced baroclinicity (as found along the eastern boundary of continents) lead to a local enhancement of EKE and a suppression of EKE further downstream as the storm track self-destructs (Kaspi and Schneider, 2011).

Personalized cumulative UV tracking on mobiles & wearables.

PubMed

Dey, S; Sahoo, S; Agrawal, H; Mondal, A; Bhowmik, T; Tiwari, V N

2017-07-01

Maintaining a balanced Ultra Violet (UV) exposure level is vital for a healthy living as the excess of UV dose can lead to critical diseases such as skin cancer while the absence can cause vitamin D deficiency which has recently been linked to onset of cardiac abnormalities. Here, we propose a personalized cumulative UV dose (CUVD) estimation system for smartwatch and smartphone devices having the following novelty factors; (a) sensor orientation invariant measurement of UV exposure using a bootstrap resampling technique, (b) estimation of UV exposure using only light intensity (lux) sensor (c) optimal UV exposure dose estimation. Our proposed method will eliminate the need for a dedicated UV sensor thus widen the user base of the proposed solution, render it unobtrusive by eliminating the critical requirement of orienting the device in a direction facing the sun. The system is implemented on android mobile platform and validated on 1200 minutes of lux and UV index (UVI) data collected across several days covering morning to evening time frames. The result shows very impressive final UVI estimation accuracy. We believe our proposed solution will enable the future wearable and smartphone users to obtain a seamless personalized UV exposure dose across a day paving a way for simple yet very useful recommendations such as right skin protective measure for reducing risk factors of long term UV exposure related diseases like skin cancer and, cardiac abnormality.

Cumulative exposure to childhood stressors and subsequent psychological distress. An analysis of US panel data.

PubMed

Björkenstam, Emma; Burström, Bo; Brännström, Lars; Vinnerljung, Bo; Björkenstam, Charlotte; Pebley, Anne R

2015-10-01

Research has shown that childhood stress increases the risk of poor mental health later in life. We examined the effect of childhood stressors on psychological distress and self-reported depression in young adulthood. Data were obtained from the Child Development Supplement (CDS) to the national Panel Study of Income Dynamics (PSID), a survey of US families that incorporates data from parents and their children. In 2005 and 2007, the Panel Study of Income Dynamics was supplemented with two waves of Transition into Adulthood (TA) data drawn from a national sample of young adults, 18-23 years old. This study included data from participants in the CDS and the TA (n = 2128), children aged 4-13 at baseline. Data on current psychological distress was used as an outcome variable in logistic regressions, calculated as odds ratios (OR) with 95% confidence intervals (CI). Latent Class Analyses were used to identify clusters based on the different childhood stressors. Associations were observed between cumulative exposure to childhood stressors and both psychological distress and self-reported depression. Individuals being exposed to three or more stressors had the highest risk (crude OR for psychological distress: 2.49 (95% CI: 1.16-5.33), crude OR for self-reported depression: 2.07 (95% CI: 1.15-3.71). However, a large part was explained by adolescent depressive symptoms. Findings support the long-term negative impact of cumulative exposure to childhood stress on psychological distress. The important role of adolescent depression in this association also needs to be taken into consideration in future studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

The cultural parameters of lead poisoning: A medical anthropologist's view of intervention in environmental lead exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trotter, R.T. II

1990-11-01

This article identifies four culturally shaped sources of lead exposure in human societies: modern and historic technological sources; food habits; culturally defined health beliefs; and beauty practices. Examples of these potential sources of lead poisoning are presented from current cultures. They include the use of lead-glazed cooking pottery in Mexican-American households; folk medical use of lead in Hispanic, Arabic, South Asian, Chinese, and Hmong communities; as well as the use of lead as a cosmetic in the Near East, Southeast Asia, and South Asia. Four interacting cultural conditions that create barriers to the reduction of lead exposure and lead poisoningmore » are identified and discussed. These are knowledge deficiencies, communication resistance, cultural reinterpretations, and incongruity of explanatory models.« less

Urban adolescent mothers exposed to community, family, and partner violence: is cumulative violence exposure a barrier to school performance and participation?

PubMed

Kennedy, Angie C; Bennett, Larry

2006-06-01

Using a risk and resilience perspective, the authors assessed urban adolescent mothers' exposure to community, family, and partner violence and analyzed the relationships between cumulative violence exposure and multiple school outcomes, within the context of welfare reforms. Positive attitude toward school and social support were examined as moderators of violence exposure on school outcomes. The authors pilot tested the questionnaire with 10 participants, then surveyed 120 adolescent mothers regarding their violence exposure, school performance and participation, positive attitude toward school, and social support. Results indicate very high rates of lifetime exposure to violence; intercorrelations and regression analyses indicate that as violence exposure increases, school outcomes tend to worsen, with positive attitude toward school found to be a significant moderator of the effects of exposure to community violence on behavior problems in school. Implications for researchers, practitioners, school policies and programs, and welfare policies and programs conclude the article.

Reduced Intellectual Development in Children with Prenatal Lead Exposure

PubMed Central

Schnaas, Lourdes; Rothenberg, Stephen J.; Flores, Maria-Fernanda; Martinez, Sandra; Hernandez, Carmen; Osorio, Erica; Velasco, Silvia Ruiz; Perroni, Estela

2006-01-01

Objective Low-level postnatal lead exposure is associated with poor intellectual development in children, although effects of prenatal exposure are less well studied. We hypothesized that prenatal lead exposure would have a more powerful and lasting impact on child development than postnatal exposure. Design We used generalized linear mixed models with random intercept and slope to analyze the pattern of lead effect of the cohort from pregnancy through 10 years of age on child IQ from 6 to 10 years. We statistically evaluated dose–response nonlinearity. Participants A cohort of 175 children, 150 of whom had complete data for all included covariates, attended the National Institute of Perinatology in Mexico City from 1987 through 2002. Evaluations/Measurements We used the Wechsler Intelligence Scale for Children–Revised, Spanish version, to measure IQ. Blood lead (BPb) was measured by a reference laboratory of the Centers for Disease Control and Prevention (CDC) quality assurance program for BPb. Results Geometric mean BPb during pregnancy was 8.0 μg/dL (range, 1–33 μg/dL), from 1 through 5 years was 9.8 μg/dL (2.8–36.4 μg/dL), and from 6 through 10 years was 6.2 μg/dL (2.2–18.6 μg/dL). IQ at 6–10 years decreased significantly only with increasing natural-log third-trimester BPb (β = −3.90; 95% confidence interval, −6.45 to −1.36), controlling for other BPb and covariates. The dose–response BPb–IQ function was log-linear, not linear–linear. Conclusions Lead exposure around 28 weeks gestation is a critical period for later child intellectual development, with lasting and possibly permanent effects. There was no evidence of a threshold; the strongest lead effects on IQ occurred within the first few micrograms of BPb. Relevance to Clinical Practice Current CDC action limits for children applied to pregnant women permit most lead-associated child IQ decreases measured over the studied BPb range. PMID:16675439

Measuring Lead Exposure in Infants, Children, and Other Sensitive Populations.

ERIC Educational Resources Information Center

National Academy of Sciences - National Research Council, Washington, DC.

Adverse health effects from exposure to lead are now recognized to be among industrialized society's most important health problems. This report, prepared by the National Research Council's Committee on Measuring Lead Exposure in Critical Populations, concurs with new findings issued by the Centers for Disease Control which state that lead…

Lead Levels in Landfill Areas and Childhood Exposure: An Integrative Review.

PubMed

Kim, M Angela; Williams, Kimberly A

2017-01-01

Landfills are high-risk areas for environmental lead exposure for children living in poverty stricken areas in many countries. This review examines landfills and lead toxicity in children. The review discusses the effects of lead toxicity, provides evidenced based recommendations to reduce lead exposure, and identify gaps in the evidence. A database search was conducted of articles in English from 1985 to 2014. Ten articles met the inclusion criteria. The Whittemore and Knafl framework and the John Hopkins Research Evidence Appraisal Tool © were used for reviewing the data. Elevated blood lead levels (BLLs) of children living near landfills were related to increased soil lead levels. Toxic effects of lead included adverse outcomes such as encephalopathy or death for children. Different approaches to decrease lead level include environmental surveillance, BLL screening, and soil abatement which are costly. Increased BLL through environmental exposure is connected with poor health outcomes and death among children. Evidence-based prevention included monitoring and screening and costly soil abatement. It is recommended that future studies focus on community education for exposure avoidance for children living near landfill areas. © 2016 Wiley Periodicals, Inc.

Aggregate-level lead exposure, gun violence, homicide, and rape.

PubMed

Boutwell, Brian B; Nelson, Erik J; Qian, Zhengmin; Vaughn, Michael G; Wright, John P; Beaver, Kevin M; Barnes, J C; Petkovsek, Melissa; Lewis, Roger; Schootman, Mario; Rosenfeld, Richard

2017-01-01

An increasing body of research has linked the geographic distribution of lead with various indicators of criminal and antisocial behavior. The current study, using data from an ongoing project related to lead exposure in St. Louis City, MO, analyzed the association between aggregate blood lead levels and specific indicators violent crime within the city. Ecological study. St. Louis, Missouri. Blood lead levels. Official reports of violent crimes were categorized as 1) crimes involving a firearm (yes/no), 2) assault crimes (with or without a firearm), 3) robbery crimes (with or without a firearm), 4) homicides and 5) rape. With the exception of rape, aggregate blood-lead levels were statistically significant predictors of violent crime at the census tract level. The risk ratios for each of the outcome measures were as follows: firearm crimes 1.03 (1.03-1.04), assault crimes 1.03 (1.02-1.03), robbery crimes 1.03 (1.02-1.04), homicide 1.03 (1.01, 1.04), and rape 1.01 (0.99-1.03). Extending prior research in St. Louis, results suggest that aggregated lead exposure at the census tract level predicted crime outcomes, even after accounting for important sociological variables. Moving forward, a more developed understanding of aggregate level crime may necessitate a shift toward studying the synergy between sociological and biological risk factors such as lead exposure.

Implications of new data on lead toxicity for managing and preventing exposure.

PubMed Central

Silbergeld, E K

1990-01-01

Recent advances in research on low-level lead poisoning point to the need to increase efforts to prevent exposure. Current biomedical consensus accepts that blood lead levels as low as 5 to 15 mcg/dL are risky to fetuses, young children, and adults. Lead at low dose is associated with increased blood pressure in adults, and chronic exposure has been associated in cohort studies with kidney disease and cancer. Data on lead toxicokinetics also points to the hazards of low-level, chronic exposure, since the lead that is accumulated over time in bone can be released at a relatively rapid rate during pregnancy and menopause. Sources that contribute to current lead exposure of the general population include unabated lead-based paint and contaminated soils, as well as lower level but pervasive sources in drinking water, food, and consumer products. PMID:2088754

Psychobiology of cumulative trauma: hair cortisol as a risk marker for stress exposure in women.

PubMed

Morris, Matthew C; Abelson, James L; Mielock, Alyssa S; Rao, Uma

2017-07-01

Childhood trauma (CT) is associated with long-lasting alterations of the hypothalamic-pituitary-adrenal (HPA) axis and elevated risk for stress exposure in adulthood. Although HPA alterations are present in the early aftermath of trauma, it remains unclear how initial HPA activity is associated with subsequent stress exposure and whether CT exposure influences the strength and direction of this association. The present study examined prospective associations between hair cortisol content (HCC) and stress exposure from baseline to 3-month follow-up in young adult women with recent (i.e. past 3 months) exposure to interpersonal violence (IPV; i.e. physical or sexual assault) and non-traumatized controls. History of significant CT abuse or neglect was determined based on clinical cutoffs for a self-report CT measure: 12 women had abuse or neglect and recent IPV exposure (CT + IPV); 7 women had abuse or neglect but no IPV exposure (CT); 15 women had no history of trauma (NTC). HCC was computed for 3 cm sections reflecting cortisol secretion during the 3 months preceding the baseline assessment. The interaction of cumulative trauma and HCC predicted stress exposure over 3-month follow-up, controlling for baseline stress exposure and depressive symptoms. Simple slopes analyses revealed that lower baseline HCC predicted greater stress exposure in the CT + IPV group compared to the CT group; HCC was not associated with stress exposure in the NTC group. The present findings highlight the potential utility of HCC as a predictor of stress exposure for women with a history of childhood abuse or neglect, particularly in the context of recent IPV. Lay summary Adults with a history of CT show long-lasting alterations in major stress response systems, including the HPA axis. They are also more likely to experience stressful life events in adulthood. However, it is not clear how altered HPA activity influences risk for stress exposure and whether CT affects their

Levels and source apportionment of children's lead exposure: could urinary lead be used to identify the levels and sources of children's lead pollution?

PubMed

Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

2015-04-01

As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Assessment of lead exposure in schoolchildren from Jakarta.

PubMed Central

Heinze, I; Gross, R; Stehle, P; Dillon, D

1998-01-01

Children attending schools in urban areas with high traffic density are a high risk group for lead poisoning. We assessed the magnitude of lead exposure in schoolchildren from Jakarta by analyzing blood lead concentrations and biomarkers of heme biosynthesis. A total of 131 children from four public elementary schools in Jakarta (two in the southern district and two in the central district) were enrolled in the study. To evaluate lead pollution in each area, soil samples and tap water were collected. The mean blood lead concentration was higher in the central district than in the southern district (8.3 +/- 2.8 vs. 6.9 +/- 3.5 microg/100 ml; p<0.05); 26.7% of the children had lead levels greater than 10 microg/100 ml. In 24% of the children, zinc protoporphyrin concentrations were over 70 micromol/mol hemoglobin; in 17% of the samples, hemoglobin was less than 11 g/100 ml. All other values were within the physiological range. Blood lead concentration and hematological biomarkers were not correlated. Analyses of tap water revealed lead values under 0. 01 mg/l; lead contamination of soil ranged from 77 to 223 ppm. Our data indicate that Indonesian children living in urban areas are at increased risk for blood lead levels above the actual acceptable limit. Activities to reduce pollution (e.g., reduction of lead in gasoline) and continuous monitoring of lead exposure are strongly recommended. Images Figure 1 PMID:9681978

Indirect lead exposure among children of radiator repair workers.

PubMed

Aguilar-Garduño, C; Lacasaña, M; Tellez-Rojo, M M; Aguilar-Madrid, G; Sanin-Aguirre, L H; Romieu, I; Hernandez-Avila, M

2003-06-01

Secondary exposure to lead has been identified as a public health problem since the late 1940s; we investigate the risk of lead exposure among families of radiator repair workers. A sample of the wives and children, aged 6 months to 6 years (exposed children) (n = 19), of radiator repair workers and a sample of children whose parents were not occupationally exposed to lead (non-exposed children) (n = 29) were matched for age and residence; their geometric mean blood lead levels are compared. Blood samples were obtained by the finger stick method and environmental dust samples by the wipe method; both were analyzed using a portable anodic stripping voltameter. Dust lead levels were significantly higher in the houses of exposed children (143.8 vs. 3.9 microg/g; P < 0.01). In crude analyses, the highest lead levels were observed among children whose fathers worked in home-based workshops (22.4 microg/dl)(n = 6). Children whose fathers worked in an external workshop (n = 13) also had high levels (14.2 microg/dl) (P < 0.01), while blood lead levels in non-exposed children were significantly lower (5.6 microg/dl)(P < 0.01). The observed differences remained significant after adjustment for age and gender. This study confirms that children of radiator repair workers are at increased risk of lead exposure and public health interventions are needed to protect them. Copyright 2003 Wiley-Liss, Inc.

Human health risk assessment of lead from mining activities at semi-arid locations in the context of total lead exposure.

PubMed

Zheng, Jiajia; Huynh, Trang; Gasparon, Massimo; Ng, Jack; Noller, Barry

2013-12-01

Lead from historical mining and mineral processing activities may pose potential human health risks if materials with high concentrations of bioavailable lead minerals are released to the environment. Since the Joint Expert Committee on Food Additives of Food and Agriculture Organization/World Health Organization withdrew the Provisional Tolerable Weekly Intake of lead in 2011, an alternative method was required for lead exposure assessment. This study evaluated the potential lead hazard to young children (0-7 years) from a historical mining location at a semi-arid area using the U.S. EPA Integrated Exposure Uptake Biokinetic (IEUBK) Model, with selected site-specific input data. This study assessed lead exposure via the inhalation pathway for children living in a location affected by lead mining activities and with specific reference to semi-arid conditions and made comparison with the ingestion pathway by using the physiologically based extraction test for gastro-intestinal simulation. Sensitivity analysis for major IEUBK input parameters was conducted. Three groups of input parameters were classified according to the results of predicted blood concentrations. The modelled lead absorption attributed to the inhalation route was lower than 2 % (mean ± SE, 0.9 % ± 0.1 %) of all lead intake routes and was demonstrated as a less significant exposure pathway to children's blood, compared with ingestion. Whilst dermal exposure was negligible, diet and ingestion of soil and dust were the dominant parameters in terms of children's blood lead prediction. The exposure assessment identified the changing role of dietary intake when house lead loadings varied. Recommendations were also made to conduct comprehensive site-specific human health risk assessment in future studies of lead exposure under a semi-arid climate.

U.S. EPA Authority to Use Cumulative Risk Assessments in Environmental Decision-Making

PubMed Central

Alves, Sarah; Tilghman, Joan; Rosenbaum, Arlene; Payne-Sturges, Devon C.

2012-01-01

Conventionally, in its decision-making, the U.S. EPA has evaluated the effects and risks associated with a single pollutant in a single exposure medium. In reality, people are exposed to mixtures of pollutants or to the same pollutant through a variety of media, including the air, water, and food. It is now more recognized than before that environmental exposure to pollutants occurs via multiple exposure routes and pathways, including inhalation, ingestion, and dermal absorption. Moreover, chemical, biologic, radiologic, physical, and psychologic stressors are all acknowledged as affecting human health. Although many EPA offices attempt to consider cumulative risk assessment and cumulative effects in various ways, there is no Agency-wide policy for considering these risks and the effects of exposure to these risks when making environmental decisions. This article examines how U.S. courts might assess EPA’s general authority and discretion to use cumulative risk assessment as the basis for developing data in support of environmental decision-making, and how courts might assess the validity of a cumulative risk assessment methodology itself. PMID:22829786

Exposure to lead in South African shooting ranges.

PubMed

Mathee, Angela; de Jager, Pieter; Naidoo, Shan; Naicker, Nisha

2017-02-01

Lead exposure in shooting ranges has been under scrutiny for decades, but no information in this regard is available in respect of African settings, and in South Africa specifically. The aim of this study was to determine the blood lead levels in the users of randomly selected private shooting ranges in South Africa's Gauteng province. An analytical cross sectional study was conducted, with participants recruited from four randomly selected shooting ranges and three archery ranges as a comparator group. A total of 118 (87 shooters and 31 archers) were included in the analysis. Shooters had significantly higher blood lead levels (BLL) compared to archers with 36/85 (42.4%) of shooters versus 2/34 (5.9%) of archers found to have a BLL ≥10μg/dl (p<0.001). Shooting ranges may constitute an import site of elevated exposure to lead. Improved ventilation, low levels of awareness of lead hazards, poor housekeeping, and inadequate personal hygiene facilities and practices at South African shooting ranges need urgent attention. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Implications of new data on lead toxicity for managing and preventing exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silbergeld, E.K.

1990-11-01

Recent advances in research on low-level lead poisoning point to the need to increase efforts to prevent exposure. Current biomedical consensus accepts that blood lead levels as low as 5 to 15 mcg/dL are risky to fetuses, young children, and adults. Lead at low dose is associated with increased blood pressure in adults, and chronic exposure has been associated in cohort studies with kidney disease and cancer. Data on lead toxicokinetics also points to the hazards of low-level, chronic exposure, since the lead that is accumulated over time in bone can be released at a relatively rapid rate during pregnancymore » and menopause. Sources that contribute to current lead exposure of the general population include unabated lead-based paint and contaminated soils, as well as lower level but pervasive sources in drinking water, food, and consumer products.« less

DIETARY EXPOSURE OF CHILDREN LIVING IN LEAD-LADEN ENVIRONMENTS

EPA Science Inventory

Children are the most susceptible population to lead exposure because of three interacting factors: they have more opportunity for contact with lead sources due to their activities; lead absorption occurs more readily in a child as compared to an adult; and the child's developmen...

Tools to Assess Community-Based Cumulative Risk and Exposures

EPA Science Inventory

Multiple agents and stressors can interact in a given community to adversely affect human and ecological conditions. A cumulative risk assessment (CRA) analyzes, characterizes, and potentially quantifies the effects from multiple stressors, which include chemical agents (for exam...

Towards the prevention of lead exposure in South Africa: contemporary and emerging challenges.

PubMed

Mathee, Angela

2014-12-01

The prevention of lead exposure continues to constitute a major public health challenge in developed countries. In well-resourced countries major lead exposure reduction interventions have resulted in significant improvements in childhood blood lead distributions. In developing countries on the other hand, while lead exposure and poisoning remain serious public health concerns, a range of prevailing factors and circumstances, such as poverty, a large informal sector, competing public health challenges, low levels of awareness of lead hazards and weak capacity to enforce legislation, contribute to an increase in the scale and intensity of the challenge, and limit the prospects of comparable success in the foreseeable future. This paper collates available information to illustrate that despite some progress, a wide range of sources of lead exist in South Africa, and that certain settings and groups continue to be at high risk of lead exposure. Lead exposure in relation to paint, mining, lead melting in subsistence fishing communities, the consumption of Ayurvedic medicines and food production is described, and discussed with regard to the key factors hindering efforts to prevent lead poisoning and exposure in South Africa and many other developing countries. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Sources of lead exposure in Mexico City

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romieu, I.; Palazuelos, E.; Cahero, G.

Many countries, including Mexico, are facing a largely unrecognized epidemic of low-level lead poisoning. Mexico is the sixth largest lead-producing country in the world, and 40% of its production is used locally in different industrial processes that cause lead contamination of the environment. The major sources and pathways of lead exposure among the Mexican population are gasoline emissions, lead-glazed ceramics, leaded paint, and lead in canned foods and beverages. In this paper we present evidence for the presence of lead in different environmental media and its impact on blood lead levels of the Mexican population. Although during the last fewmore » years important measures have been implemented problem in Mexico. There is an urgent need for regulatory policies that implement stricter control to protect the Mexican Population. There is also a need to develop adequate programs to reduce the lead burden and the associated health effects in the population that has been chronically exposed. 37 refs., 1 fig., 8 tabs.« less

Cumulative exposure to biologics and risk of cancer in psoriasis patients: A meta-analysis of Psonet studies from Israel, Italy, Spain, United Kingdom and Republic of Ireland.

PubMed

Garcia-Doval, I; Descalzo, M A; Mason, K J; Cohen, A D; Ormerod, A D; Gómez-García, F J; Cazzaniga, S; Feldhamer, I; Ali, H; Herrera-Acosta, E; Griffiths, C E M; Stern, R; Naldi, L

2018-05-03

Cancer risk following long-term exposure to systemic immunomodulatory therapies in psoriasis patients is possible. To assess a dose-response relationship between cumulative length of exposure to biologic therapy and risk of cancer. Four national studies (a healthcare database from Israel, and prospective cohorts form Italy, Spain and UK/ROI) collaborating through Psonet (European Registry of Psoriasis) participated in these nested case-control studies, including nearly 60.000 person-years of observation. Cases were patients who developed an incident cancer. Patients with previous cancers and benign or in-situ tumours were excluded. Four cancer-free controls were matched to each case on year of birth, gender, geographic area, and registration year. Follow-up for controls was censored at the date of cancer diagnosis for the matched case. Conditional logistic regression was performed by each registry. Results were pooled using random effects meta-analysis. 728 cases and 2671 controls were identified. After matching, differences between cases and controls were present for the Charlson comorbidity index in all three registries, and in the prevalence of previous exposure to psoralen-ultraviolet-A (PUVA) and smoking (BADBIR only). The risk of first cancers was not significantly associated with cumulative exposure to biologics (adjusted odds ratio per year of exposure 1.02; 95%CI 0.92, 1.13). Results were similar if squamous and basal cell carcinomas were included in the outcome. Cumulative length of exposure to biologic therapies of psoriasis patients in real-world clinical practice does not appear to be linked to a higher risk of cancer after several years of use. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Cumulative Exposure to Cell-Free HIV in Breast Milk, Rather Than Feeding Pattern per se, Identifies Postnatally Infected Infants

PubMed Central

Neveu, Dorine; Viljoen, Johannes; Bland, Ruth M.; Nagot, Nicolas; Danaviah, Siva; Coutsoudis, Anna; Rollins, Nigel Campbell; Coovadia, Hoosen M.; Van de Perre, Philippe; Newell, Marie-Louise

2011-01-01

Background. We quantified the relationship between human immunodeficiency virus (HIV) RNA shedding in breast milk, cumulative RNA exposure, and postnatal transmission, relating timing of infection in the infant to estimated total volume of milk exposure. Methods. Nested case-control study of 36 infants of HIV-infected mothers. Case patients were infants who acquired HIV infection through breastfeeding from age 6 through 28 weeks, and control subjects were uninfected infants matched on age at obtainment of a breast milk sample. Mothers and infants received peripartum single-dose nevirapine prophylaxis. Feeding data were collected daily; breast milk samples were collected and infant anthropometry was performed at 6 weeks and monthly thereafter. Volume of milk ingested was estimated using infant weight and feeding pattern. Results. Before HIV acquisition in case patients, feeding pattern (exclusive breastfeeding; median duration, 65 vs 70 days; P = .6) and daily milk intake (mean volume, 638 vs 637 mL; P = .97) did not differ significantly between case patients and control subjects. Case mothers were more likely to shed virus (64% vs 9% always, 22% vs 20.5% intermittently, 14% vs 70.5% never shed; overall, P < .001). Case patients ingested ∼15 times more HIV-1 RNA particles than did control subjects (196.5 vs 13 × 106 copies; P < .001). Allowing for maternal antenatal CD4 cell count and plasma HIV-1 load, child sex and duration of mixed breastfeeding, the association between HIV RNA exposure and infection remained statistically significant (P < .001). Conclusions. Postnatal acquisition of HIV-1 is more strongly associated with cumulative exposure to cell-free particles in breast milk than with feeding mode. Reducing breast milk viral load through antiretroviral therapy to mother or child can further decrease postnatal transmission in exclusively breastfed infants. PMID:21367736

CUMULATIVE RISK ANALYSIS FOR ORGANOPHOSPHORUS PESTICIDES

EPA Science Inventory

Cumulative Risk Analysis for Organophosphorus Pesticides
R. Woodrow Setzer, Jr. NHEERL MD-74, USEPA, RTP, NC 27711

The US EPA has recently completed a risk assessment of the effects of exposure to 33 organophosphorous pesticides (OPs) through the diet, water, and resi...

The Role of Cumulative Trauma, Betrayal, and Appraisals in Understanding Trauma Symptomatology.

PubMed

Martin, Christina Gamache; Cromer, Lisa Demarni; Deprince, Anne P; Freyd, Jennifer J

2013-03-01

Poor psychological outcomes are common among trauma survivors, yet not all survivors experience adverse sequelae. The current study examined links between cumulative trauma exposure as a function of the level of betrayal (measured by the relational closeness of the survivor and the perpetrator), trauma appraisals, gender, and trauma symptoms. Participants were 273 college students who reported experiencing at least one traumatic event on a trauma checklist. Three cumulative indices were constructed to assess the number of different types of traumas experienced that were low (LBTs), moderate (MBTs), or high in betrayal (HBTs). Greater trauma exposure was related to more symptoms of depression, dissociation, and PTSD, with exposure to HBTs contributing the most. Women were more likely to experience HBTs than men, but there were no gender differences in trauma-related symptoms. Appraisals of trauma were predictive of trauma-related symptoms over and above the effects explained by cumulative trauma at each level of betrayal. The survivor's relationship with the perpetrator, the effect of cumulative trauma, and their combined impact on trauma symptomatology are discussed.

The Role of Cumulative Trauma, Betrayal, and Appraisals in Understanding Trauma Symptomatology

PubMed Central

Martin, Christina Gamache; Cromer, Lisa DeMarni; DePrince, Anne P.; Freyd, Jennifer J.

2012-01-01

Poor psychological outcomes are common among trauma survivors, yet not all survivors experience adverse sequelae. The current study examined links between cumulative trauma exposure as a function of the level of betrayal (measured by the relational closeness of the survivor and the perpetrator), trauma appraisals, gender, and trauma symptoms. Participants were 273 college students who reported experiencing at least one traumatic event on a trauma checklist. Three cumulative indices were constructed to assess the number of different types of traumas experienced that were low (LBTs), moderate (MBTs), or high in betrayal (HBTs). Greater trauma exposure was related to more symptoms of depression, dissociation, and PTSD, with exposure to HBTs contributing the most. Women were more likely to experience HBTs than men, but there were no gender differences in trauma-related symptoms. Appraisals of trauma were predictive of trauma-related symptoms over and above the effects explained by cumulative trauma at each level of betrayal. The survivor’s relationship with the perpetrator, the effect of cumulative trauma, and their combined impact on trauma symptomatology are discussed. PMID:23542882

Paternal occupational lead exposure and offspring risks for schizophrenia.

PubMed

Sallmén, Markku; Suvisaari, Jaana; Lindbohm, Marja-Liisa; Malaspina, Dolores; Opler, Mark G

2016-10-01

This register-based cohort study investigated whether paternal occupational exposure to inorganic lead was related to offspring risk for schizophrenia spectrum disorder (SSD). Exposed men (n=11,863) were identified from blood lead measurements taken at the Finnish Institute of Occupational Health in 1973-1983. Data on mothers and their offspring born from 1972-1984 were obtained from the national Population Information System. Two population comparison offspring for each exposed offspring were matched on date of birth, sex and area (n=23,720). SSD cases were identified from The Finnish Hospital Discharge Register. Hazard ratios of SSD between exposed groups were analyzed using conditional proportional hazards regression, adjusted for parental history of psychoses, parental ages, language of offspring, father's employment, and father's self-employment. After 26-38years of follow up, there were no significant differences in the incidence of schizophrenia, either between the offspring of exposed (188/11,863; 1.6%) and unexposed fathers (347/23,720; 1.5%) or based on blood lead levels (adjusted hazard ratios (aHR): 0.97, CI 0.52-1.83, 1.25, CI 0.85-1.82, 0.90, CI 0.54-1.49, and 1.38, CI 0.65-2.92 for lead categories <0.5, 0.5-0.9, 1.0-1.4, and ≥1.5μmol/L, respectively, as compared to population comparison). Parental psychosis, paternal age and offspring language were associated with offspring risk. The findings suggest that paternal exposure to lead is not a risk factor for schizophrenia in offspring. However, the majority of exposed fathers had low-level exposure, and we cannot exclude the possibility of an effect for higher exposures to lead. Copyright © 2016 Elsevier B.V. All rights reserved.

Economic costs of childhood lead exposure in low- and middle-income countries.

PubMed

Attina, Teresa M; Trasande, Leonardo

2013-09-01

Children's blood lead levels have declined worldwide, especially after the removal of lead in gasoline. However, significant exposure remains, particularly in low- and middle-income countries. To date, there have been no global estimates of the costs related to lead exposure in children in developing countries. Our main aim was to estimate the economic costs attributable to childhood lead exposure in low- and middle-income countries. We developed a regression model to estimate mean blood lead levels in our population of interest, represented by each 1-year cohort of children < 5 years of age. We used an environmentally attributable fraction model to estimate lead-attributable economic costs and limited our analysis to the neurodevelopmental impacts of lead, assessed as decrements in IQ points. Our main outcome was lost lifetime economic productivity due to early childhood exposure. We estimated a total cost of $977 billions of international dollars in low- and middle-income countries, with economic losses equal to $134.7 billion in Africa [4.03% of gross domestic product (GDP)], $142.3 billion in Latin America and the Caribbean (2.04% of GDP), and $699.9 billion in Asia (1.88% of GDP). Our sensitivity analysis indicates a total economic loss in the range of $728.6-1162.5 billion. We estimated that, in low- and middle-income countries, the burden associated with childhood lead exposure amounts to 1.20% of world GDP in 2011. For comparison, in the United States and Europe lead-attributable economic costs have been estimated at $50.9 and $55 billion, respectively, suggesting that the largest burden of lead exposure is now borne by low- and middle-income countries.

Lead exposure from backyard chicken eggs: a public health risk?

PubMed

Bautista, Adrienne C; Puschner, Birgit; Poppenga, Robert H

2014-09-01

Although the USA has made significant strides in reducing lead exposure, new and emerging sources are raising cause for public concern. Recent reports of finding lead in eggs from chickens raised in urban gardens has highlighted the need to consider the potential health risks of consuming eggs from backyard chickens. Following the detection of 0.33 μg/g lead in the edible portion of eggs submitted for lead analysis from a backyard chicken owner, further investigation was conducted to determine the source and extent of lead exposure in the flock. Several birds, almost two dozen eggs, and environmental samples were submitted to the California Animal Health and Food Safety Laboratory for further testing. Lead was detected in the blood, liver, kidney, and bone at varying concentrations in all birds but was not detected in the muscle tissue. All egg shells contained detectable amounts of lead, while only a little over half of the edible portion of the eggs contained lead. The detected concentrations in the edible portion approached or exceeded the recommended threshold of lead consumption per day that should not be exceeded by young children if a child consumed one average-sized egg. Peeling paint from a wooded structure adjacent to the flock's coop was the likely lead source containing 3,700 μg/g lead. Thus, removal of the chickens from the source and periodic testing of eggs for lead were recommended. This case illustrates the need for consumers and health care workers to be aware of potential sources for lead exposure such as backyard chickens.

Lead exposure reduces sperm quality and DNA integrity in mice.

PubMed

Li, Cuiling; Zhao, Kai; Zhang, Huiping; Liu, Lili; Xiong, Fei; Wang, Kunyu; Chen, Biao

2018-05-01

Toxicity of lead on male reproductive functions has raised wide public concern as environmental lead contamination remains common worldwide. Conflicting and controversial data are available regarding effects of lead on male fertility. More importantly, our knowledge on effects of lead on sperm DNA integrity is significantly limited. Thus, further studies should focus on this issue. In the current study, adult male mice were exposed to a series of lead acetate concentrations in drinking water for six weeks. Following administration, lead levels in blood, testicles, and epididymis were measured, and potential changes in morphology of testis and epididymis due to lead exposure were identified. We also analyzed sperm parameters, including sperm density, viability, motility, and morphology, to evaluate quality of sperm collected from epididymis. Especially, hypothetical influence of lead on sperm DNA integrity was also evaluated by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling, alkaline comet assay, and sperm chromatin structure assay. Lead exposure possibly exerted no effect on growth of mice because these animals acquired similar body weight gain during the experimental period. However, high lead concentrations (0.5% and 1%) in drinking water affected sperm motility and increased percentage of spermatozoa with abnormal morphology. In groups treated with 0.25%, 0.5%, and 1% lead acetate, percentages of sperm cells showing DNA breaks and chromatin structure damage significantly increased. Altogether, lead exposure not only exhibits adverse effects on sperm physiological parameters, but also impairs DNA structure and integrity. These effects may lead to significant decline in male fertility. © 2018 Wiley Periodicals, Inc.

Cumulative organophosphate pesticide exposure and risk assessment among pregnant women living in an agricultural community: a case study from the CHAMACOS cohort.

PubMed Central

Castorina, Rosemary; Bradman, Asa; McKone, Thomas E; Barr, Dana B; Harnly, Martha E; Eskenazi, Brenda

2003-01-01

Approximately 230,000 kg of organophosphate (OP) pesticides are applied annually in California's Salinas Valley. These activities have raised concerns about exposures to area residents. We collected three spot urine samples from pregnant women (between 1999 and 2001) enrolled in CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas), a longitudinal birth cohort study, and analyzed them for six dialkyl phosphate metabolites. We used urine from 446 pregnant women to estimate OP pesticide doses with two deterministic steady-state modeling methods: method 1, which assumed the metabolites were attributable entirely to a single diethyl or dimethyl OP pesticide; and method 2, which adapted U.S. Environmental Protection Agency (U.S. EPA) draft guidelines for cumulative risk assessment to estimate dose from a mixture of OP pesticides that share a common mechanism of toxicity. We used pesticide use reporting data for the Salinas Valley to approximate the mixture to which the women were exposed. Based on average OP pesticide dose estimates that assumed exposure to a single OP pesticide (method 1), between 0% and 36.1% of study participants' doses failed to attain a margin of exposure (MOE) of 100 relative to the U.S. EPA oral benchmark dose(10) (BMD(10)), depending on the assumption made about the parent compound. These BMD(10) values are doses expected to produce a 10% reduction in brain cholinesterase activity compared with background response in rats. Given the participants' average cumulative OP pesticide dose estimates (method 2) and regardless of the index chemical selected, we found that 14.8% of the doses failed to attain an MOE of 100 relative to the BMD(10) of the selected index. An uncertainty analysis of the pesticide mixture parameter, which is extrapolated from pesticide application data for the study area and not directly quantified for each individual, suggests that this point estimate could range from 1 to 34%. In future analyses, we

Economic Costs of Childhood Lead Exposure in Low- and Middle-Income Countries

PubMed Central

Trasande, Leonardo

2013-01-01

Background: Children’s blood lead levels have declined worldwide, especially after the removal of lead in gasoline. However, significant exposure remains, particularly in low- and middle-income countries. To date, there have been no global estimates of the costs related to lead exposure in children in developing countries. Objective: Our main aim was to estimate the economic costs attributable to childhood lead exposure in low- and middle-income countries. Methods: We developed a regression model to estimate mean blood lead levels in our population of interest, represented by each 1-year cohort of children < 5 years of age. We used an environmentally attributable fraction model to estimate lead-attributable economic costs and limited our analysis to the neurodevelopmental impacts of lead, assessed as decrements in IQ points. Our main outcome was lost lifetime economic productivity due to early childhood exposure. Results: We estimated a total cost of $977 billions of international dollars in low- and middle-income countries, with economic losses equal to $134.7 billion in Africa [4.03% of gross domestic product (GDP)], $142.3 billion in Latin America and the Caribbean (2.04% of GDP), and $699.9 billion in Asia (1.88% of GDP). Our sensitivity analysis indicates a total economic loss in the range of $728.6–1162.5 billion. Conclusions: We estimated that, in low- and middle-income countries, the burden associated with childhood lead exposure amounts to 1.20% of world GDP in 2011. For comparison, in the United States and Europe lead-attributable economic costs have been estimated at $50.9 and $55 billion, respectively, suggesting that the largest burden of lead exposure is now borne by low- and middle-income countries. Citation: Attina TM, Trasande L. 2013. Economic costs of childhood lead exposure in low- and middle-income countries. Environ Health Perspect 121:1097–1102; http://dx.doi.org/10.1289/ehp.1206424 PMID:23797342

Combined exposure to cyanobacterial biomass, lead and the Newcastle virus enhances avian toxicity.

PubMed

Pikula, Jiri; Bandouchova, Hana; Hilscherova, Klara; Paskova, Veronika; Sedlackova, Jana; Adamovsky, Ondrej; Knotkova, Zora; Lany, Petr; Machat, Jiri; Marsalek, Blahoslav; Novotny, Ladislav; Pohanka, Miroslav; Vitula, Frantisek

2010-10-01

Under environmental conditions, wild birds can be exposed to multiple stressors including natural toxins, anthropogenic pollutants and infectious agents at the same time. This experimental study was successful in testing the hypothesis that adverse effects of cyanotoxins, heavy metals and a non-pathogenic immunological challenge combine to enhance avian toxicity. Mortality occurred in combined exposures to naturally occurring cyanobacterial biomass and lead shots, lead shots and Newcastle vaccination as well as in single lead shot exposure. Mostly acute effects around day 10 were observed. On day 30 of exposure, there were no differences in the liver accumulation of lead in single and combined exposure groups. Interestingly, liver microcystin levels were elevated in birds co-exposed to cyanobacterial biomass together with lead or lead and the Newcastle virus. Significant differences in body weights between all Pb-exposed and Pb-non-exposed birds were found on days 10 and 20. Single exposure to cyanobacterial biomass resulted in hepatic vacuolar dystrophy, whereas co-exposure with lead led to more severe granular dystrophy. Haematological changes were associated with lead exposure, in particular. Biochemical analysis revealed a decrease in glucose and an increase in lactate dehydrogenase in single and combined cyanobacterial and lead exposures, which also showed a decreased antibody response to vaccination. The combined exposure of experimental birds to sub-lethal doses of individual stressors is ecologically realistic. It brings together new pieces of knowledge on avian health. In light of this study, investigators of wild bird die-offs should be circumspect when evaluating findings of low concentrations of contaminants that would not result in mortality on a separate basis. As such it has implications for wildlife biologists, veterinarians and conservationists of avian biodiversity. Copyright 2010 Elsevier B.V. All rights reserved.

Epigenetics, obesity and early-life cadmium or lead exposure

PubMed Central

Park, Sarah S; Skaar, David A; Jirtle, Randy L; Hoyo, Cathrine

2017-01-01

Obesity is a complex and multifactorial disease, which likely comprises multiple subtypes. Emerging data have linked chemical exposures to obesity. As organismal response to environmental exposures includes altered gene expression, identifying the regulatory epigenetic changes involved would be key to understanding the path from exposure to phenotype and provide new tools for exposure detection and risk assessment. In this report, we summarize published data linking early-life exposure to the heavy metals, cadmium and lead, to obesity. We also discuss potential mechanisms, as well as the need for complete coverage in epigenetic screening to fully identify alterations. The keys to understanding how metal exposure contributes to obesity are improved assessment of exposure and comprehensive establishment of epigenetic profiles that may serve as markers for exposures. PMID:27981852

Epigenetics, obesity and early-life cadmium or lead exposure.

PubMed

Park, Sarah S; Skaar, David A; Jirtle, Randy L; Hoyo, Cathrine

2017-01-01

Obesity is a complex and multifactorial disease, which likely comprises multiple subtypes. Emerging data have linked chemical exposures to obesity. As organismal response to environmental exposures includes altered gene expression, identifying the regulatory epigenetic changes involved would be key to understanding the path from exposure to phenotype and provide new tools for exposure detection and risk assessment. In this report, we summarize published data linking early-life exposure to the heavy metals, cadmium and lead, to obesity. We also discuss potential mechanisms, as well as the need for complete coverage in epigenetic screening to fully identify alterations. The keys to understanding how metal exposure contributes to obesity are improved assessment of exposure and comprehensive establishment of epigenetic profiles that may serve as markers for exposures.

Cumulative and episodic vaccine aluminum exposure in a population-based cohort of young children.

PubMed

Glanz, Jason M; Newcomer, Sophia R; Daley, Matthew F; McClure, David L; Baxter, Roger P; Jackson, Michael L; Naleway, Allison L; Lugg, Marlene M; DeStefano, Frank

2015-11-27

In addition to antigens, vaccines contain small amounts of preservatives, adjuvants, and residual substances from the manufacturing process. Some parents have concerns about the safety of these ingredients, yet no large epidemiological studies have specifically examined associations between health outcomes and vaccine ingredients, other than thimerosal. This study examined the extent to which the Vaccine Safety Datalink (VSD) could be used to study vaccine ingredient safety in children. Children born 2004-2011 were identified in VSD data. Using immunization records, two cohorts were identified: children who were up-to-date and children who were undervaccinated before age 2 years. A database was also created linking vaccine type and manufacturer with ingredient amounts documented in vaccine package inserts. Thirty-four ingredients in two or more infant vaccines were identified. However, only amounts (in mg) for aluminum were consistently documented and commonly contained in infant vaccines. Analyses compared vaccine aluminum exposure across cohorts and determined the statistical power for studying associations between aluminum exposure and hypothetical vaccine adverse events. Among 408,608 children, mean cumulative vaccine aluminum exposure increased from 1.11 to 4.00 mg between ages 92-730 days. Up-to-date children were exposed to 11-26% more aluminum from vaccines than undervaccinated children. Power analyses demonstrated that safety studies of aluminum could detect relative risks ranging from 1.1 to 5.8 for a range of adverse event incidence. The safety of vaccine aluminum exposure can be feasibly studied in the VSD. However, possible biological mechanisms and confounding variables would need to be considered before conducting any studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Recent Developments in Low-Level Lead Exposure and Intellectual Impairment in Children

PubMed Central

Koller, Karin; Brown, Terry; Spurgeon, Anne; Levy, Len

2004-01-01

In the last decade children’s blood lead levels have fallen significantly in a number of countries, and current mean levels in developed countries are in the region of 3 μg/dL. Despite this reduction, childhood lead poisoning continues to be a major public health problem for certain at-risk groups of children, and concerns remain over the effects of lead on intellectual development in infants and children. The evidence for lowered cognitive ability in children exposed to lead has come largely from prospective epidemiologic studies. The current World Health Organization/Centers for Disease Control and Prevention blood level of concern reflects this and stands at 10 μg/dL. However, a recent study on a cohort of children whose lifetime peak blood levels were consistently < 10 μg/dL has extended the association of blood lead and intellectual impairment to lower levels of lead exposure and suggests there is no safety margin at existing exposures. Because of the importance of this finding, we reviewed this study in detail along with other recent developments in the field of low-level lead exposure and children’s cognitive development. We conclude that these findings are important scientifically, and efforts should continue to reduce childhood exposure. However, from a public health perspective, exposure to lead should be seen within the many other risk factors impacting on normal childhood development, in particular the influence of the learning environment itself. Current lead exposure accounts for a very small amount of variance in cognitive ability (1–4%), whereas social and parenting factors account for 40% or more. PMID:15198918

Lead concentration in meat from lead-killed moose and predicted human exposure using Monte Carlo simulation.

PubMed

Lindboe, M; Henrichsen, E N; Høgåsen, H R; Bernhoft, A

2012-01-01

Lead-based hunting ammunitions are still common in most countries. On impact such ammunition releases fragments which are widely distributed within the carcass. In Norway, wild game is an important meat source for segments of the population and 95% of hunters use lead-based bullets. In this paper, we have investigated the lead content of ground meat from moose (Alces alces) intended for human consumption in Norway, and have predicted human exposure through this source. Fifty-two samples from different batches of ground meat from moose killed with lead-based bullets were randomly collected. The lead content was measured by atomic absorption spectroscopy. The lead intake from exposure to moose meat over time, depending on the frequency of intake and portion size, was predicted using Monte Carlo simulation. In 81% of the batches, lead levels were above the limit of quantification of 0.03 mg kg(-1), ranging up to 110 mg kg(-1). The mean lead concentration was 5.6 mg kg(-1), i.e. 56 times the European Commission limit for lead in meat. For consumers eating a moderate meat serving (2 g kg(-1) bw), a single serving would give a lead intake of 11 µg kg(-1) bw on average, with maximum of 220 µg kg(-1) bw. Using Monte Carlo simulation, the median (and 97.5th percentile) predicted weekly intake of lead from moose meat was 12 µg kg(-1) bw (27 µg kg(-1) bw) for one serving per week and 25 µg kg(-1) bw (45 µg kg(-1) bw) for two servings per week. The results indicate that the intake of meat from big game shot with lead-based bullets imposes a significant contribution to the total human lead exposure. The provisional tolerable weekly intake set by the World Health Organization (WHO) of 25 µg kg(-1) bw is likely to be exceeded in people eating moose meat on a regular basis. The European Food Safety Authority (EFSA) has recently concluded that adverse effects may be present at even lower exposure doses. Hence, even occasional consumption of big game meat with lead levels as

Cognitive development and low-level lead exposure in poly-drug exposed children.

PubMed

Min, Meeyoung O; Singer, Lynn T; Kirchner, H Lester; Minnes, Sonia; Short, Elizabeth; Hussain, Zehra; Nelson, Suchitra

2009-01-01

The impact of early postnatal lead exposure measured at age 4 on children's IQ and academic achievement at and 11 years of age was examined. The sample consisted of 278 inner-city, primarily African American children who were polydrug exposed prenatally. Regression analyses indicated a linear effect of lead exposure on outcomes and no moderating effects of polydrug exposure. An IQ loss of about 4.1-5.4 Full Scale IQ points was estimated for each 10 microg/dL increase in blood lead level at ages 4, 9, and 11 years as a function of blood lead level at age 4. Decrements in scores on tests of non-verbal reasoning were consistently associated with higher lead levels at age 4, while verbal decrements became apparent only at age 11. Lower reading summary scores at 9 and 11 years were consistently associated with higher lead exposure, while decrements in mathematics were not apparent until 11 years. Subgroup analyses on children with blood lead levels <10 microg/dL showed detrimental lead effects even at the 5 microg/dL level, providing additional evidence of adverse effects occurring at blood lead levels below the current 10 microg/dL public health blood lead action level.

Cognitive Development and Low-Level Lead Exposure in Poly-Drug Exposed Children

PubMed Central

Min, Meeyoung O.; Singer, Lynn T.; Kirchner, H. Lester; Minnes, Sonia; Short, Elizabeth; Hussain, Zehra; Nelson, Suchitra

2009-01-01

The impact of early postnatal lead exposure measured at age 4 on children’s IQ and academic achievement at 4, 9, and 11 years of age was examined. The sample consisted of 278 inner-city, primarily African American children who were polydrug exposed prenatally. Regression analyses indicated a linear effect of lead exposure on outcomes and no moderating effects of polydrug exposure. An IQ loss of about 4.1–5.4 Full Scale IQ points was estimated for each 10 ug/dl increase in blood lead level at ages 4, 9, and 11 years as a function of blood lead level at age 4. Decrements in scores on tests of non-verbal reasoning were consistently associated with higher lead levels at age 4, while verbal decrements became apparent only at age 11. Lower reading summary scores at 9 and 11 years were consistently associated with higher lead exposure, while decrements in mathematics were not apparent until 11 years. Subgroup analyses on children with blood lead levels < 10 μg/dL showed detrimental lead effects even at the 5 μg/dL level, providing additional evidence of adverse effects occurring at blood lead levels below the current 10 μg/dL public health blood lead action level. PMID:19345261

Does exposure to glyphosate lead to an increase in the micronuclei frequency? A systematic and meta-analytic review.

PubMed

Ghisi, Nédia de Castilhos; de Oliveira, Elton Celton; Prioli, Alberto José

2016-02-01

Glyphosate-based herbicides are among the most used pesticides worldwide. Reviews on the safety of glyphosate have been conducted by several regulatory agencies and researches centers, many times with contradictory results. This study is a systematic meta-analytical review of experimental studies on the relationship between exposure to the glyphosate (GLY) and its formulations with the formation of micronuclei (MN) to establish a quantitative estimate of the environmental risks. The natural logarithm (ln) of the estimated response ratio was calculated from 81 experiments. A meta-analysis was performed on the complete data set, and individual meta-analyses were conducted after stratification by test system, class of vertebrate, exposure route, gender, endpoints, type of literature, formulation, GLY dose and exposure time. A forest plot showed an overall positive association between GLY exposure and its formulations and MN, corroborated by the cumulative effects size. Different responses were observed on mammalian and non-mammalian. Interesting results was noticed in exposure route where oral administration of GLY presented no significance. Exposure by intraperitoneal injection presented the highest MN formation. Pure GLY caused fewer effects than to commercial mixtures, but both presented mutagenic effects. The studies with males presented significant responses, while studies with females were not significant. The cumulative effects size was not clearly related to GLY dose, and was negatively related to exposure time. It can be attributed to different test systems, exposure routes and protocols analyzed. In conclusion, our results support the hypothesis that exposure to GLY and its formulations increases the frequency of MN formation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Childhood lead poisoning and the new Centers for Disease Control and Prevention guidelines for lead exposure.

PubMed

Schnur, Julie; John, Rita Marie

2014-05-01

This article will give a brief history, review the latest guidelines, discuss risk factors and sources, and discuss screening, diagnosis, and management of lead poisoning in children. Additionally, the role of the nurse practitioner (NP) caring for children will be reviewed. Review of published literature on lead poisoning and the 2012 lead prevention guidelines of the Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP) of the Centers for Disease Control and Prevention (CDC). While lead poisoning levels have decreased over the past several decades, newer research has shown that even low levels of lead in the blood can have negative effects on children's intelligence and neurodevelopment. As a result, ACCLPP of the CDC issued new, stricter lead prevention guidelines in 2012. Lead exposure and lead poisoning are pediatric public health risks. Studies have shown that no level of lead is considered safe, and the emphasis has shifted to primary prevention of lead exposure. Despite the focus on primary prevention, the NP must remain vigilant in history taking, exploring risk factors, and screening children in order to assure the best possible outcome. ©2014 The Author(s) ©2014 American Association of Nurse Practitioners.

The effect of the OSHA lead exposure in construction standard on blood lead levels among iron workers employed in bridge rehabilitation.

PubMed

Levin, S M; Goldberg, M; Doucette, J T

1997-03-01

Over 50,000 workers are at risk of occupational exposure to lead in the course of renovating the nation's deteriorating infrastructure. In mid-1993, to control exposure to lead in the construction setting OSHA promulgated a Lead in Construction Standard. In this study, we assessed the effect of the mandated changes in exposure conditions which followed the introduction of this new standard. We analyzed changes in baseline and maximum blood lead concentrations and in maximum increments in blood lead levels before and after introduction of the standard among iron workers employed in the renovation of a large, lead-painted, steel bridge in New York City. Results indicated that baseline and maximum blood lead levels fell significantly after the implementation of the provisions of the standard, as did maximum increments in blood lead concentrations. Seventy-six percent of the workers maintained blood lead concentrations below 20 micrograms/dl after the OSHA standard, as compared with 66% prior to its implementation. Increments of 20 micrograms/dl or more occurred considerably more frequently before introduction of the standard (13% before vs. 4% after; p = 0.01). Evidence of decreased exposure to lead was observed among iron workers who were present both before and after the introduction of the OSHA standard, as well as among iron workers newly hired after the OSHA provisions were put in place. These findings document the effectiveness of the OSHA construction lead standard in controlling exposure to lead in this complex and variable environment. The data indicate the utility of blood lead determinations in assessing the outcome of industrial hygiene interventions to reduce exposures to lead in the construction setting.

Low lifetime stress exposure is associated with reduced stimulus–response memory

PubMed Central

Goldfarb, Elizabeth V.; Shields, Grant S.; Daw, Nathaniel D.; Slavich, George M.; Phelps, Elizabeth A.

2017-01-01

Exposure to stress throughout life can cumulatively influence later health, even among young adults. The negative effects of high cumulative stress exposure are well-known, and a shift from episodic to stimulus–response memory has been proposed to underlie forms of psychopathology that are related to high lifetime stress. At the other extreme, effects of very low stress exposure are mixed, with some studies reporting that low stress leads to better outcomes, while others demonstrate that low stress is associated with diminished resilience and negative outcomes. However, the influence of very low lifetime stress exposure on episodic and stimulus–response memory is unknown. Here we use a lifetime stress assessment system (STRAIN) to assess cumulative lifetime stress exposure and measure memory performance in young adults reporting very low and moderate levels of lifetime stress exposure. Relative to moderate levels of stress, very low levels of lifetime stress were associated with reduced use and retention (24 h later) of stimulus–response (SR) associations, and a higher likelihood of using context memory. Further, computational modeling revealed that participants with low levels of stress exhibited worse expression of memory for SR associations than those with moderate stress. These results demonstrate that very low levels of stress exposure can have negative effects on cognition. PMID:28298555

Association of lead exposure, serum uric acid and parameters of renal function in Nigerian lead-exposed workers.

PubMed

Alasia, D D; Emem-Chioma, P C; Wokoma, F S

2010-10-01

The presence of hyperuricemia and renal function impairment, especially in the absence of urate stone formation is strongly suggestive of lead nephropathy. The evaluation of this association is essential in areas where lead exposure is still prevalent and uncontrolled. To determine the relationship between serum uric acid and renal function indices in lead-exposed workers. A cross-sectional study of 190 adults with occupational lead exposure and 80 adults (comparison group), matched for age and sex was performed in Port Harcourt, South-south Nigeria. Blood lead was used as the biomarker of lead exposure while serum urea, serum creatinine, urine albumin (using urine albumin:creatinine ratio), estimated glomerular filtration rate (GFR) and serum uric acid were the renal function indices measured. Occupationally lead-exposed subjects had a significantly (p = 0.008) higher mean±SD blood lead levels (50.37±24.58 μg/dL) than the comparison group (41.40±26.85). The mean±SD serum urea (8.6±2.3 mg/dL), creatinine (1.0±0.2 mg/dL) and serum uric acid (4.6±1.2 mg/dL) were significantly (p < 0.01) higher in the study subjects than the comparison group (7.6±2.4, 0.9±0.2, and 3.9±1.1 mg/dL, respectively). The mean±SD creatinine clearance was significantly (p = 0.002) lower in the study subjects than the comparison group (98.9±21.3 vs. 108.2±25.2 mL/min/1.72 m2). Serum uric acid level correlated positively with serum creatinine (r = 0.134) and negatively with GFR (r = -0.151). People with occupational lead exposure are at risk of developing hyperuricemia and renal impairment.

Evaluating Cumulative OP Pesticide Body Burden of Children: A National Case Study

PubMed Central

Payne-Sturges, Devon; Cohen, Jonathan; Castorina, Rosemary; Axelrad, Daniel A.; Woodruff, Tracey J.

2009-01-01

Biomonitoring is a valuable tool for identifying exposures to chemicals that pose potential harm to human health. However, to date there has been little published on ways to evaluate the relative public health significance of biomonitoring data for different chemicals, and even less on cumulative assessment of multiple chemicals. The objectives of our study are to develop a methodology for a health risk interpretation of biomonitoring data, and to apply it using NHANES 1999–2002 body burden data for organophosphorus (OP) pesticides. OP pesticides present a particularly challenging case given the non-specificity of many metabolites monitored through NHANES. We back-calculate OP pesticide exposures from urinary metabolite data, and compare cumulative dose estimates with available toxicity information for a common mechanism of action (brain cholinesterase inhibition) using data from U.S. EPA. Our results suggest that approximately 40% of children in the United States may have had insufficient margins of exposure (MOEs) for neurological impacts from cumulative exposures to OP pesticides (MOE less than 1,000). Limitations include uncertainty related to assumptions about likely precursor pesticide compounds of the urinary metabolites, sources of exposure, and intra-individual and temporal variability. PMID:19921915

Human cumulative culture: a comparative perspective.

PubMed

Dean, Lewis G; Vale, Gill L; Laland, Kevin N; Flynn, Emma; Kendal, Rachel L

2014-05-01

Many animals exhibit social learning and behavioural traditions, but human culture exhibits unparalleled complexity and diversity, and is unambiguously cumulative in character. These similarities and differences have spawned a debate over whether animal traditions and human culture are reliant on homologous or analogous psychological processes. Human cumulative culture combines high-fidelity transmission of cultural knowledge with beneficial modifications to generate a 'ratcheting' in technological complexity, leading to the development of traits far more complex than one individual could invent alone. Claims have been made for cumulative culture in several species of animals, including chimpanzees, orangutans and New Caledonian crows, but these remain contentious. Whilst initial work on the topic of cumulative culture was largely theoretical, employing mathematical methods developed by population biologists, in recent years researchers from a wide range of disciplines, including psychology, biology, economics, biological anthropology, linguistics and archaeology, have turned their attention to the experimental investigation of cumulative culture. We review this literature, highlighting advances made in understanding the underlying processes of cumulative culture and emphasising areas of agreement and disagreement amongst investigators in separate fields. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

Two cases of acute lead poisoning due to occupational exposure to lead.

PubMed

Ogawa, Masanori; Nakajima, Yoshiaki; Kubota, Ryuichi; Endo, Yoko

2008-04-01

We experienced two cases of acute lead poisoning due to occupational exposure to lead. The patients were engaged in stripping off antirust compounds including Pb from a bridge and re-painting it at the same work place. Both patients exhibited colic, arthralgia, and anemia. Blood lead levels were 73.1 microg/dl and 96.3 microg/dl. Intravenous CaEDTA chelation therapy was therefore performed. After chelation, blood lead levels decreased and symptoms gradually disappeared. Although the patients were working with protective equipment, the workplace was in the mountains and there was no water for washing. The patients were thus unable to washing their hands and faces. We assume that they swallowed lead dust left on their hands and faces when they removed their clothing, and believe that this poisoning occurred due to lack of knowledge sufficient for protection.

Food contamination as a pathway for lead exposure in children during the 2010-2013 lead poisoning epidemic in Zamfara, Nigeria.

PubMed

Tirima, Simba; Bartrem, Casey; von Lindern, Ian; von Braun, Margrit; Lind, Douglas; Anka, Shehu Mohamed; Abdullahi, Aishat

2018-05-01

In 2010, an estimated 400 to 500 children died of acute lead poisoning associated with artisanal gold mining in Zamfara, Nigeria. Processing of gold ores containing up to 10% lead within residential compounds put residents, especially children, at the highest risk. Principal routes of exposure were incidental ingestion and inhalation of contaminated soil and dusts. Several Nigerian and international health organizations collaborated to reduce lead exposures through environmental remediation and medical treatment. The contribution of contaminated food to total lead exposure was assessed during the environmental health response. Objectives of this investigation were to assess the influence of cultural/dietary habits on lead exposure pathways and estimate the contribution of contaminated food to children's blood lead levels (BLLs). A survey of village dietary practices and staple food lead content was conducted to determine dietary composition, caloric intakes, and lead intake. Potential blood lead increments were estimated using bio-kinetic modeling techniques. Most dietary lead exposure was associated with contamination of staple cereal grains and legumes during post-harvest processing and preparation in contaminated homes. Average post-harvest and processed cereal grain lead levels were 0.32mg/kg and 0.85mg/kg dry weight, respectively. Age-specific food lead intake ranged from 7 to 78μg/day. Lead ingestion and absorption were likely aggravated by the dusty environment, fasting between meals, and nutritional deficiencies. Contamination of staple cereal grains by highly bioavailable pulverized ores could account for as much as 11%-34% of children's BLLs during the epidemic, and were a continuing source after residential soil remediation until stored grain inventories were exhausted. Copyright © 2017. Published by Elsevier B.V.

New directions in the toxicokinetics of human lead exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mushak, P.

An important determinant of body lead (Pb) burden and Pb toxicity in exposed humans is Pb metabolism, or more correctly, Pb toxicokinetics. It affects the former through the quantitative processes of uptake, distribution and retention/excretion and the latter via delivery of toxic doses to cellular/molecular sites of action. Pb toxicokinetics has useful application in understanding Pb's behavior in populations. Several of these applications have been studied and results are presented for the toxicokinetic basis of dose-neurotoxic effect relationships in selected longitudinal studies and the use of toxicokinetic modeling for estimation of body lead burden in early populations. Three well-known, ongoingmore » longitudinal studies of developmental neurotoxicity--in Boston, Cincinnati, and Port Pirie, Australia--involve cohorts who differ markedly as to their pre- and postnatal lead exposure profiles. Toxicokinetic examination of these exposure differences helps to explain the temporal variability seen in blood Pb-toxic effect relationships and supports a causal role for lead. Toxicokinetic models of Pb uptake and in-vivo behavior are increasingly being considered for estimating Pb-B levels in lieu of direct measurement. A linear biokinetic model, using reliable input data for natural/prehistoric levels of Pb in sources, was applied to estimation of prehistoric/preindustrial children's blood lead. A range of 0.06 to 0.12 microgram/dl was estimated for two lead intakes. These estimates are still two orders of magnitude (85 to 165-fold) lower than the newly issued CDC toxicity guideline for children of 10 micrograms/dl. Lastly, the toxicokinetics of lead in bone, particularly its resorption with metabolic stimuli, is of concern, particularly for baby boom women who are either of childbearing age or approaching menopause and who had greatly elevated environmental lead exposures in the 1940s to 1970s. 115 refs.« less

A non-linear relationship between the cumulative exposure to occupational stressors and nurses' burnout and the potentially emotion regulation factors.

PubMed

Sun, Ji-Wei; Lin, Ping-Zhen; Zhang, Hui-Hui; Li, Jia-Huan; Cao, Feng-Lin

2017-10-08

Stressful situations can increase the likelihood of nurses experiencing negative emotions, especially burnout. To explore the association of cumulative exposure to occupational stressors and emotion regulation strategies with nurses' burnout. Participants were 602 nurses from three general hospitals in Jinan, China. Social demographic characteristics, occupational stress, burnout, and emotion regulation strategies (cognitive reappraisal, expressive suppression, and rumination), were assessed. Nearly 70% of nurses reported that they were burnt out. Those with a moderate level and high level of stressors were 3.203 times and 26.444 times more likely to have burnout, respectively (x 2 trend = 62.732). Logistic regression revealed that nurses had higher cognitive reappraisal score (odds ratios (OR) = 0.941), scored lower for burnout. Those who had higher expressive suppression score (OR = 1.054), higher rumination score (OR = 1.037), and a higher level of stressors (OR = 2.779-18.259) scored higher for burnout. The results of sensitivity analysis were similar. A non-linear relationship exists between the cumulative exposure to occupational stressors and nurses' burnout. Those who less frequently use cognitive reappraisal, more frequently use rumination and expressive suppression, and have a high level of stressors may be more likely to experience burnout.

Lead exposure and fear-potentiated startle in the VA Normative Aging Study: a pilot study of a novel physiological approach to investigating neurotoxicant effects.

PubMed

Grashow, Rachel; Miller, Mark W; McKinney, Ann; Nie, Linda H; Sparrow, David; Hu, Howard; Weisskopf, Marc G

2013-01-01

Physiologically-based indicators of neural plasticity in humans could provide mechanistic insights into toxicant actions on learning in the brain, and perhaps prove more objective and sensitive measures of such effects than other methods. We explored the association between lead exposure and classical conditioning of the acoustic startle reflex (ASR)-a simple form of associative learning in the brain-in a population of elderly men. Fifty-one men from the VA Normative Aging Study with cumulative bone lead exposure measurements made with K-X-Ray-Fluorescence participated in a fear-conditioning protocol. The mean age of the men was 75.5years (standard deviation [sd]=5.9) and mean patella lead concentration was 22.7μg/g bone (sd=15.9). Baseline ASR eyeblink response decreased with age, but was not associated with subsequent conditioning. Among 37 men with valid responses at the end of the protocol, higher patella lead was associated with decreased awareness of the conditioning contingency (declarative learning; adjusted odds ratio [OR] per 20μg/g patella lead=0.91, 95% confidence interval [CI]: 0.84, 0.99, p=0.03). Eyeblink conditioning (non-declarative learning) was 0.44sd less (95% CI: -0.91, 0.02; p=0.06) per 20μg/g patella lead after adjustment. Each result was stronger when correcting for the interval between lead measurement and startle testing (awareness: OR=0.88, 95% CI: 0.78, 0.99, p=0.04; conditioning: -0.79sd less, 95% CI: -1.56, 0.03, p=0.04). This initial exploration suggests that lead exposure interferes with specific neural mechanisms of learning and offers the possibility that the ASR may provide a new approach to physiologically explore the effects of neurotoxicant exposures on neural mechanisms of learning in humans with a paradigm that is directly comparable to animal models. Copyright © 2013 Elsevier Inc. All rights reserved.

Time-cumulated blood pressure exposure and incident impairment of glucose tolerance and diabetes mellitus.

PubMed

Wu, Yun Tao; Song, Lu; Liu, Xiao Xue; Gao, Jing Sheng; Zheng, Xiao Ming; Ruan, Chun Yu; Zhao, Hai Yan; Chen, Shuo Hua; Gao, Wen Yuan; Jonas, Jost B; Wu, Shou Ling

2017-05-02

With the marked increase in the prevalence of diabetes mellitus, it was the purpose of our study to assess a potential association of time-cumulated exposure to systolic (CumSBP) and of diastolic blood pressure (CumDBP) with onset of impaired glucose tolerance and diabetes mellitus. The prospective investigation included participants of the longitudinal Kailuan Study with three baseline examinations in 2006-2007, 2008-2009 and 2010-2011, re-examination in 2012-2013, and no diabetes mellitus at baseline. Cumulative blood pressure (BP) was calculated as cumBP = [(BP 1  + BP 2 )/2 × time 1-2 ] + [(BP 2  + BP 3 )/2 × time 2-3 ]. Based on cumSBP, the study population was stratified into four groups (cumSBP < 480mmHgxyear;n = 15,339; 480mmHgxyear ≤ cumSBP < 520mmHgxyear;n = 7214; 520mmHgxyears ≤ cumSBP < 560mmHgxyears;n = 5675; and cumSBP ≥ 560mmHgxyears;n = 10,576). After adjusting for demographic, anthropomorphic, biochemical, socioeconomic and lifestyle parameters and as compared with the first group, the second, third and fourth group showed a significantly higher incidence of diabetes (P-trend < 0.001;hazard ratio (HR);95% confidence interval (CI):1.28(1.08,1.51),1.54(1.29,1.84), and 2.33(1.98,2.73), respectively), higher incidence of impairment of glucose tolerance (P-trend < 0.001;HR;95% CI1.17(1.02,1.33), 1.43(1.25,1.64), and 2.09(1.85,2.37), respectively), and higher incidence of diabetes developing out of an impairment of glucose tolerance (P-trend < 0.001;HR;95% CI:1.22(0.97,1.54),1.47(1.16,1.86), and 2.01(1.62,2.50), respectively). An increase in cumSBP by 10 mmHg/year or an increase in cumDBP by 5 mmHg/year was associated with a hazard ratio of incident diabetes of 1.04 (95% CI:1.03,1.04) and 1.02(1.02,1.03), respectively, with a hazard ratio of incident impairment of glucose tolerance of 1.04(95% CI:1.03,1.04) and 1.03(95% CI:1.02,1.03), respectively, and with a hazard ratio of incident diabetes developing

Chronic lead exposure induces cochlear oxidative stress and potentiates noise-induced hearing loss.

PubMed

Jamesdaniel, Samson; Rosati, Rita; Westrick, Judy; Ruden, Douglas M

2018-08-01

Acquired hearing loss is caused by complex interactions of multiple environmental risk factors, such as elevated levels of lead and noise, which are prevalent in urban communities. This study delineates the mechanism underlying lead-induced auditory dysfunction and its potential interaction with noise exposure. Young-adult C57BL/6 mice were exposed to: 1) control conditions; 2) 2 mM lead acetate in drinking water for 28 days; 3) 90 dB broadband noise 2 h/day for two weeks; and 4) both lead and noise. Blood lead levels were measured by inductively coupled plasma mass spectrometry analysis (ICP-MS) lead-induced cochlear oxidative stress signaling was assessed using targeted gene arrays, and the hearing thresholds were assessed by recording auditory brainstem responses. Chronic lead exposure downregulated cochlear Sod1, Gpx1, and Gstk1, which encode critical antioxidant enzymes, and upregulated ApoE, Hspa1a, Ercc2, Prnp, Ccl5, and Sqstm1, which are indicative of cellular apoptosis. Isolated exposure to lead or noise induced 8-12 dB and 11-25 dB shifts in hearing thresholds, respectively. Combined exposure induced 18-30 dB shifts, which was significantly higher than that observed with isolated exposures. This study suggests that chronic exposure to lead induces cochlear oxidative stress and potentiates noise-induced hearing impairment, possibly through parallel pathways. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Childhood Lead Exposure After the Phaseout of Leaded Gasoline: An Ecological Study of School-Age Children in Kampala, Uganda

PubMed Central

Graber, Lauren K.; Asher, Daniel; Anandaraja, Natasha; Bopp, Richard F.; Merrill, Karen; Cullen, Mark R.; Luboga, Samuel; Trasande, Leonardo

2010-01-01

Background Tetraethyl lead was phased out of gasoline in Uganda in 2005. Recent mitigation of an important source of lead exposure suggests examination and re-evaluation of the prevalence of childhood lead poisoning in this country. Ongoing concerns persist about exposure from the Kiteezi landfill in Kampala, the country’s capital. Objectives We determined blood lead distributions among Kampala schoolchildren and identified risk factors for elevated blood lead levels (EBLLs; ≥ 10 μg/dL). Analytical approach Using a stratified, cross-sectional design, we obtained blood samples, questionnaire data, and soil and dust samples from the homes and schools of 163 4- to 8-year-old children representing communities with different risks of exposure. Results The mean blood lead level (BLL) was 7.15 μg/dL; 20.5% of the children were found to have EBLL. Multivariable analysis found participants whose families owned fewer household items, ate canned food, or used the community water supply as their primary water source to have higher BLLs and likelihood of EBLLs. Distance < 0.5 mi from the landfill was the factor most strongly associated with increments in BLL (5.51 μg/dL, p < 0.0001) and likelihood of EBLL (OR = 4.71, p = 0.0093). Dust/soil lead was not significantly predictive of BLL/EBLL. Conclusions Lead poisoning remains highly prevalent among school-age children in Kampala. Confirmatory studies are needed, but further efforts are indicated to limit lead exposure from the landfill, whether through water contamination or through another mechanism. Although African nations are to be lauded for the removal of lead from gasoline, this study serves as a reminder that other sources of exposure to this potent neurotoxicant merit ongoing attention. PMID:20194080

Reducing lead in air and preventing childhood exposure near lead smelters: learning from the U.S. experience.

PubMed

Sullivan, Marianne

2015-05-01

Childhood lead exposure and poisoning near primary lead smelters continues in developed and developing countries. In the United States, the problem of lead poisoning in children caused by smelter emissions was first documented in the early 1970s. In 1978, Environmental Protection Agency set National Ambient Air Quality Standards for lead. Attainment of this lead standard in areas near operating lead smelters took twenty to thirty years. Childhood lead exposure and poisoning continued to occur after the lead National Ambient Air Quality Standards were set and before compliance was achieved. This article analyzes and discusses the factors that led to the eventual achievement of the 1978 lead National Ambient Air Quality Standards near primary smelters and the reduction of children's blood lead levels in surrounding communities. Factors such as federal and state regulation, monitoring of emissions, public health activities such as blood lead surveillance and health education, relocation of children, environmental group and community advocacy, and litigation all played a role. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Environmental lead exposure to toll booth workers in Hong Kong

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, T.C.; Wong, L.T.L.; Lam, C.W.K.

1988-01-01

A survey of workers in the Lion Rock Tunnel toll booths was conducted, as they were regarded as a high risk group in lead exposure due to high density of vehicular traffic. The exposure of the workers to lead was determined by continuous sapling of air around the breathing zone of workers inside the booths. Blood lead concentration of 50 workers showed a mean of 0.65 {mu}mol/L and the mean urine lead concentration was 0.14 {mu}mol/L. Other tests, such as urinary amino-levulinic acid (ALA), erythrocyte zinc protoporphyrin (ZnPP) and hemoglobin concentration (Hb), were also preformed. The blood lead concentrations andmore » other biological parameters of the toll-booth workers were acceptable and may be attributed to the recent legislation to lower the lead content in petrol and to the good preventive measures taken by the management.« less

Acute lead exposure increases arterial pressure: role of the renin-angiotensin system.

PubMed

Simões, Maylla Ronacher; Ribeiro Júnior, Rogério F; Vescovi, Marcos Vinícius A; de Jesus, Honério C; Padilha, Alessandra S; Stefanon, Ivanita; Vassallo, Dalton V; Salaices, Mercedes; Fioresi, Mirian

2011-04-11

Chronic lead exposure causes hypertension and cardiovascular disease. Our purpose was to evaluate the effects of acute exposure to lead on arterial pressure and elucidate the early mechanisms involved in the development of lead-induced hypertension. Wistar rats were treated with lead acetate (i.v. bolus dose of 320 µg/Kg), and systolic arterial pressure, diastolic arterial pressure and heart rate were measured during 120 min. An increase in arterial pressure was found, and potential roles of the renin-angiotensin system, Na(+),K(+)-ATPase and the autonomic reflexes in this change in the increase of arterial pressure found were evaluated. In anesthetized rats, lead exposure: 1) produced blood lead levels of 37±1.7 µg/dL, which is below the reference blood concentration (60 µg/dL); 2) increased systolic arterial pressure (Ct: 109±3 mmHg vs Pb: 120±4 mmHg); 3) increased ACE activity (27% compared to Ct) and Na(+),K(+)-ATPase activity (125% compared to Ct); and 4) did not change the protein expression of the α1-subunit of Na(+),K(+)-ATPase, AT(1) and AT(2). Pre-treatment with an AT(1) receptor blocker (losartan, 10 mg/Kg) or an ACE inhibitor (enalapril, 5 mg/Kg) blocked the lead-induced increase of arterial pressure. However, a ganglionic blockade (hexamethonium, 20 mg/Kg) did not prevent lead's hypertensive effect. Acute exposure to lead below the reference blood concentration increases systolic arterial pressure by increasing angiotensin II levels due to ACE activation. These findings offer further evidence that acute exposure to lead can trigger early mechanisms of hypertension development and might be an environmental risk factor for cardiovascular disease.

Primary prevention of lead exposure--blood lead results at age two years.

PubMed

Campbell, Carla; Gracely, Edward; Tran, Mary; Starkey, Naomi; Kersten, Hans; Palermo, Peter; Rothman, Nancy; Line, Laura; Hansen-Turton, Tine

2012-04-01

The Philadelphia Lead Safe Homes (LSH) Study was designed to evaluate whether educational and environmental interventions in the first year of life for families of newborns increased knowledge of lead exposure prevention and were associated with less elevation of blood lead levels (BLLs) for these children, when compared to children receiving standard care. The current study performed descriptive statistics on the second-year BLL data for both groups and compared these using chi-square tests for proportions and unpaired t-tests for means. A BLL result was found for 159 (50.6%) of the 314 LSH cohort children and 331 (52.7%) of the 628 control children (p = 0.1). Mean and standard deviation for age at draw was 23.8 (3.4) months versus 23.6 (3.1) months (P = 0.6). Geometric mean BLLs were 3.7 versus 3.5 µg/dL (P = 0.4). The percentages of the cohort group with a BLL of ≥ 20, ≥ 10 and ≥ 5 μg/dL, respectively, were 0.6%, 5% and 30%; for the controls 1.2%, 6.6%, and 25%. These percentages were not significantly different between groups. A comparison of geometric mean BLLs and percentages above several BLL cut points drawn at age two years in a group of urban newborns benefitting from study interventions versus a group of similar urban children did not yield statistically significant differences. Both groups had relatively lower lead levels when compared to historical cohort groups, which may reflect a continuing downward trend in BLLs in U.S. children. The interventions did result in benefits to the families such as an increase in parental knowledge about lead exposure prevention and in-home wet cleaning activity, and a decrease in lead dust levels in study homes.

Effects of occupational lead exposure.

PubMed

Wang, Y L; Lu, P K; Chen, Z Q; Liang, Y X; Lu, Q M; Pan, Z Q; Shao, M

1985-01-01

Fifty-three workers in a battery factory, 52 solderers in a television factory, and 50 embroidery workers (a reference group) were studied. The average air lead levels of the three workplaces were 0.578 mg/m3, 0.002 mg/m3, and 0.001 mg/m3, respectively. Adverse effects in terms of clinical manifestations and biochemical criteria were evident among the battery factory workers. A significant dose-response relationship existed between the toxic effects and the air lead levels. The solderers showed no apparent abnormalities in comparison with the embroidery workers. The early clinical manifestations were dysfunction of the central nervous system, indigestion, arthralgia, and myalgia in the extremities. A positive association was observed between the prevalence of fatigue, mild abdominal pain, and arthralgia and the blood lead (PbB), urinary lead (PbU), and zinc protoporphyrin (ZPP) levels. The symptomatic threshold values of PbB, PbU, and ZPP were 30 micrograms/dl (1.5 mumol/l), 0.045 mg/l (0.2 mumol/l), and 40 micrograms/dl (0.7 mumol/l), respectively. The PbB, PbU, free erythrocyte protoporphyrin, and ZPP levels and the blood aminolevulinic dehydratase ratio could be used as indicators of lead exposure, although ZPP is preferred for a preventive monitoring program. The motor and sensory conduction velocities of the median nerve were slower in the exposed groups than in the reference group. No effects on behavioral function were observed among the solderers.

Sex-based differences in gene expression in hippocampus following postnatal lead exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schneider, J.S., E-mail: jay.schneider@jefferson.edu; Anderson, D.W.; Sonnenahalli, H.

The influence of sex as an effect modifier of childhood lead poisoning has received little systematic attention. Considering the paucity of information available concerning the interactive effects of lead and sex on the brain, the current study examined the interactive effects of lead and sex on gene expression patterns in the hippocampus, a structure involved in learning and memory. Male or female rats were fed either 1500 ppm lead-containing chow or control chow for 30 days beginning at weaning.Blood lead levels were 26.7 {+-} 2.1 {mu}g/dl and 27.1 {+-} 1.7 {mu}g/dl for females and males, respectively. The expression of 175more » unique genes was differentially regulated between control male and female rats. A total of 167 unique genes were differentially expressed in response to lead in either males or females. Lead exposure had a significant effect without a significant difference between male and female responses in 77 of these genes. In another set of 71 genes, there were significant differences in male vs. female response. A third set of 30 genes was differentially expressed in opposite directions in males vs. females, with the majority of genes expressed at a lower level in females than in males. Highly differentially expressed genes in males and females following lead exposure were associated with diverse biological pathways and functions. These results show that a brief exposure to lead produced significant changes in expression of a variety of genes in the hippocampus and that the response of the brain to a given lead exposure may vary depending on sex. - Highlights: > Postnatal lead exposure has a significant effect on hippocampal gene expression patterns. > At least one set of genes was affected in opposite directions in males and females. > Differentially expressed genes were associated with diverse biological pathways.« less

Phthalates and Cumulative Risk Assessment (NAS Final ...

EPA Pesticide Factsheets

On December 18, 2008, the National Academy of Sciences' National Research Council released a final report, requested and sponsored by the EPA, entitled Phthalates and Cumulative Risk Assessment: The Task Ahead. Risk assessment has become a dominant public policy tool for making choices, based on limited resources, to protect public health and the environment. It has been instrumental to the mission of the U.S. Environmental Protection Agency (EPA) as well as other federal agencies in evaluating public health concerns, informing regulatory and technological decisions, prioritizing research needs and funding, and in developing approaches for cost-benefit analysis. People are exposed to a variety of chemicals throughout their daily lives. To protect public health, regulators use risk assessments to examine the effects of chemical exposures. This book provides guidance for assessing the risk of phthalates, chemicals found in many consumer products that have been shown to affect the development of the male reproductive system of laboratory animals. Because people are exposed to multiple phthalates and other chemicals that affect male reproductive development, a cumulative risk assessment should be conducted that evaluates the combined effects of exposure to all these chemicals. The book suggests an approach for cumulative risk assessment that can serve as a model for evaluating the health risks of other types of chemicals.

Pediatric lead exposure from imported Indian spices and cultural powders.

PubMed

Lin, Cristiane Gurgel; Schaider, Laurel Anne; Brabander, Daniel Joseph; Woolf, Alan David

2010-04-01

Significant lead poisoning has been associated with imported nonpaint products. To describe cases of pediatric lead intoxication from imported Indian spices and cultural powders, determine lead concentrations in these products, and predict effects of ingestion on pediatric blood lead levels (BLLs). Cases and case-study information were obtained from patients followed by the Pediatric Environmental Health Center (Children's Hospital Boston). Imported spices (n = 86) and cultural powders (n = 71) were analyzed for lead by using x-ray fluorescence spectroscopy. The simple bioaccessibility extraction test was used to estimate oral bioavailability. The integrated exposure uptake biokinetic model for lead in children was used to predict population-wide geometric mean BLLs and the probability of elevated BLLs (>10 microg/dL). Four cases of pediatric lead poisoning from Indian spices or cultural powders are described. Twenty-two of 86 spices and foodstuff products contained >1 microg/g lead (for these 22 samples, mean: 2.6 microg/g [95% confidence interval: 1.9-3.3]; maximum: 7.6 microg/g). Forty-six of 71 cultural products contained >1 microg/g lead (for 43 of these samples, mean: 8.0 microg/g [95% confidence interval: 5.2-10.8]; maximum: 41.4 microg/g). Three sindoor products contained >47% lead. With a fixed ingestion of 5 microg/day and 50% bioavailability, predicted geometric mean BLLs for children aged 0 to 4 years increased from 3.2 to 4.1 microg/dL, and predicted prevalence of children with a BLL of >10 microg/dL increased more than threefold (0.8%-2.8%). Chronic exposure to spices and cultural powders may cause elevated BLLs. A majority of cultural products contained >1 microg/g lead, and some sindoor contained extremely high bioaccessible lead levels. Clinicians should routinely screen for exposure to these products.

Lead exposure is a risk for worsening bone mineral density in middle-aged male workers.

PubMed

Akbal, Ayla; Tutkun, Engin; Yılmaz, Hınç

2014-09-01

Lead exposure linked to osteoporosis in women. However, there is no direct evidence whether lead exposure has effects on bone metabolism in middle-aged male subjects. Therefore, the present study investigated the relationship between bone mineral densitometry measurements, bone markers, endocrine hormones and blood lead levels. The present study included lead exposure patients (n: 30) and control subjects (n: 32). We recorded information on patient demographics and risk factors of osteoporosis. Blood lead levels were evaluated using Varian AA 240Z atomic absorption spectrophotometry. Bone mineral density measurements were measured using dual-energy X-ray absorptiometry. Each lumbar T and Z scores in the lead exposure group were lower than the control group. There were no significant differences in femur neck and femur total T and Z scores between two groups. Blood lead levels were also negatively correlated with lumbar 2-4 T score, total lumbar T score, lumbar 2-4 Z score and total lumbar Z score. Urinary hydroxyproline and urinary deoxypyridinoline levels in the lead exposure group were significantly higher compared to controls. Blood lead levels were strong, positively correlated with urinary deoxypyridinoline. Endocrine hormone levels and 1,25-dihydroxy-vitamin D3 levels were comparable between lead exposure and control group. Lead exposure in male workers is an important factor for deterioration in bone mineral density. We should be screening blood lead levels and history of lead exposure in male osteoporosis.

Windows of lead exposure sensitivity, attained height, and body mass index at 48 months.

PubMed

Afeiche, Myriam; Peterson, Karen E; Sánchez, Brisa N; Schnaas, Lourdes; Cantonwine, David; Ettinger, Adrienne S; Solano-González, Maritsa; Hernández-Avila, Mauricio; Hu, Howard; Téllez-Rojo, Martha M

2012-06-01

To examine longitudinal associations of prenatal, infancy, and early childhood lead exposure during sensitive periods with height and body mass index (BMI). A total of 773 participants were recruited between 1994 and 2005 in Mexico City. Lead exposure history categories were constructed for the prenatal period (maternal patellar lead concentration) and for infancy and childhood (mean child blood lead concentration at birth to 24 months and 30-48 months, respectively). Linear regression models were used to study lead exposure history with height and BMI at 48 months. Mean height at age 48 months was significantly lower in children with a blood lead level exceeding the median during infancy (-0.84 cm; 95% CI, -1.42 to -0.25) than in children with a level below the median. Prenatal lead exposure was not associated with height at 48 months. Results for attained BMI generally trended in the same direction as for height. Our findings suggest an effect of lead exposure early in life on height attainment at 48 months, with the exposure window of greatest sensitivity in infancy. Copyright © 2012 Mosby, Inc. All rights reserved.

Emotion dysregulation mediates the relationship between lifetime cumulative adversity and depressive symptomatology.

PubMed

Abravanel, Benjamin T; Sinha, Rajita

2015-02-01

Repeated exposure to stressful events across the lifespan, referred to as cumulative adversity, is a potent risk factor for depression. Research indicates that cumulative adversity detrimentally affects emotion regulation processes, which may represent a pathway linking cumulative adversity to vulnerability to depression. However, empirical evidence that emotion dysregulation mediates the relationship between cumulative adversity and depression is limited, particularly in adult populations. We examined the direct and indirect effects of cumulative adversity on depressive symptomatology in a large community sample of adults (n = 745) who were further characterized by risk status: never-depressed (n = 638) and "at-risk" remitted mood-disordered (n = 107). All participants completed the Cumulative Adversity Inventory (CAI), the Difficulties in Emotion Regulation Scale (DERS), and the Center for Epidemiologic Studies Depression Scale (CES-D). Bootstrapped confidence intervals were computed to estimate the indirect effect of emotion dysregulation on the relationship between cumulative adversity and depressive symptomatology and to test whether this indirect effect was moderated by risk status. Emotion dysregulation partially and significantly mediated the relationship between cumulative adversity and depressive symptomatology independent of risk status. Overall, cumulative adversity and emotion dysregulation accounted for 50% of the variance in depressive symptomatology. These findings support the hypothesis that disruption of adaptive emotion regulation processes associated with repeated exposure to stressful life events represents an intrapersonal mechanism linking the experience of adverse events to depression. Our results support the utility of interventions that simultaneously emphasize stress reduction and emotion regulation to treat and prevent depressive vulnerability and pathology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Emotion Dysregulation Mediates the Relationship between Lifetime Cumulative Adversity and Depressive Symptomatology

PubMed Central

Abravanel, Benjamin T.; Sinha, Rajita

2014-01-01

Repeated exposure to stressful events across the lifespan, referred to as cumulative adversity, is a potent risk factor for depression. Research indicates that cumulative adversity detrimentally affects emotion regulation processes, which may represent a pathway linking cumulative adversity to vulnerability to depression. However, empirical evidence that emotion dysregulation mediates the relationship between cumulative adversity and depression is limited, particularly in adult populations. We examined the direct and indirect effects of cumulative adversity on depressive symptomatology in a large community sample of adults (n = 745) who were further characterized by risk status: never-depressed (n = 638) and “at-risk” remitted mood-disordered (n = 107). All participants completed the Cumulative Adversity Inventory (CAI), the Difficulties in Emotion Regulation Scale (DERS), and the Center for Epidemiologic Studies Depression Scale (CES-D). Bootstrapped confidence intervals were computed to estimate the indirect effect of emotion dysregulation on the relationship between cumulative adversity and depressive symptomatology and to test whether this indirect effect was moderated by risk status. Emotion dysregulation partially and significantly mediated the relationship between cumulative adversity and depressive symptomatology independent of risk status. Overall, cumulative adversity and emotion dysregulation accounted for 50% of the variance in depressive symptomatology. These findings support the hypothesis that disruption of adaptive emotion regulation processes associated with repeated exposure to stressful life events represents an intrapersonal mechanism linking the experience of adverse events to depression. Our results support the utility of interventions that simultaneously emphasize stress reduction and emotion regulation to treat and prevent depressive vulnerability and pathology. PMID:25528603

Performance and exposure indices of rats exposed to low concentrations of lead.

PubMed

Cory-Slechta, D A; Weiss, B; Cox, C

1985-04-01

To further characterize the lower end of the function relating lead exposure and biological exposure indices to behavior, male weanling rats were exposed chronically to drinking solutions containing 25 ppm sodium acetate (controls) or 25 ppm lead acetate. Behavioral training began when the animals reached 50 days of age, and performance on a fixed-interval 1-min schedule of food reinforcement was then assessed over 90 experimental sessions (136 days). This exposure produced overall response rate increases over the first 40 sessions that were similar to those observed previously with higher concentrations of lead. Response rates of the two groups tended to merge subsequently. The increased overall response rates in the treated group derived primarily from an increased frequency of shorter interresponse times (IRTs) and increased running rates (calculated without the postreinforcement interval). Blood lead (PbB) and zinc protoporphyrin (ZPP) values were determined following sessions 30, 60, and 90. PbB values of the lead-exposed group averaged 15 to 20 micrograms/dl throughout the study; ZPP did not differ. The mean brain lead value of the treated group was 0.07 micrograms Pb/g. Blood-brain ratios (1.38 to 4.06) were substantially greater than those previously observed at higher exposures. These data extend to even lower exposures, and lower blood lead concentrations, the effective concentration for behavioral effects, and further emphasize the importance of the sensitivity of the endpoint in assessing behavioral toxicity.

Lead exposures and biological responses in military weapons systems: Aerosol characteristics and acute lead effects among US Army artillerymen: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, M.H.; Stebbings, J.H.; Peterson, D.P.

1993-03-01

This study was to determine the concentration and chemical nature of lead (Pb) aerosols produced during the firing of artillery and to determine the exposures and biological responses of crew members exposed to lead aerosols during such firing. The concentrations of lead-containing aerosols at crew positions depended on wind conditions, with higher concentrations when firing into a head wind. Aerosol concentrations were highest in the muzzle blast zone. Concentrations of lead in the blood of crew members rose during the first 12 days of exposure to elevated airborne lead concentrations and then leveled off. There was no rapid decrease inmore » blood lead concentrations after completion of firing. Small decreases in hematocrit and small increases in free erythrocyte porphyrin were correlated with increasing exposure to airborne lead. These changes were reversed by seven weeks after firing. Changes in nerve conduction velocity had borderline statistical significance to airborne lead exposure. In measuring nerve conduction velocity, differences in skin temperature must be taken into account.« less

Evaluation of preventive and control measures for lead exposure in a South African lead-acid battery recycling smelter.

PubMed

Dyosi, Sindiswa

2007-10-01

In South Africa, new lead regulations released in February 2002 served as motivation for a cross-sectional study investigating the effectiveness of preventive and control measures implemented in a lead smelter that recycles lead-acid batteries. Twenty-two workers were observed and interviewed. Structured questionnaires were used to gather workers' personal information, perception about their work environment, health risks, and work practices. Retrospective data from air monitoring and medical surveillance programs were obtained from the plant's records. The smelter implemented a number of control measures for lead exposure, including engineering controls, administrative controls, and, as a last resort, personal protective equipment. Engineering controls were rated the best control measure and included local exhaust ventilation systems and wet methods. Positive pressure systems were used in the offices and laboratory. The local exhaust ventilation system was rated the best engineering control measure. Although control measures were used, areas such as smelting and refinery had average lead in air levels above 0.15 mg/m(3), the occupational exposure limit for lead. This was a concern especially with regard to the smelting area because those workers had the second highest mean blood lead levels; workers in the battery breaking area had the highest. Regular use of personal protective equipment by some workers in the "lead exposure zones" was not observed. Although the mean blood lead levels had been below 40 micro g/dL for more than 90% of the workers since 2001, more than 70% of workers reported concerns about their health while working in the smelter. Even though control measures were implemented, they were not adequate because in some areas lead in air exceeded the occupational exposure limit. Therefore, improvement of existing measures and regular monitoring of personal protective equipment use were included in the recommendations given to the smelter.

The Influence of Lead Exposure and Toxicity to Children's Neurological Development and School Performance.

ERIC Educational Resources Information Center

Kimball, Sarah L.

This report discusses the effects of lead exposure and toxicity on children's cognitive development and school performance and addresses the role of schools in prevention of lead poisoning. Sources of lead exposure include mining, smelting and refining activities, lead paint, leaded gasoline, and industrial emissions. The results of lead poisoning…

Children's Lead Exposure: A Multimedia Modeling Analysis to Guide Public Health Decision-Making.

PubMed

Zartarian, Valerie; Xue, Jianping; Tornero-Velez, Rogelio; Brown, James

2017-09-12

Drinking water and other sources for lead are the subject of public health concerns around the Flint, Michigan, drinking water and East Chicago, Indiana, lead in soil crises. In 2015, the U.S. Environmental Protection Agency (EPA)'s National Drinking Water Advisory Council (NDWAC) recommended establishment of a "health-based, household action level" for lead in drinking water based on children's exposure. The primary objective was to develop a coupled exposure-dose modeling approach that can be used to determine what drinking water lead concentrations keep children's blood lead levels (BLLs) below specified values, considering exposures from water, soil, dust, food, and air. Related objectives were to evaluate the coupled model estimates using real-world blood lead data, to quantify relative contributions by the various media, and to identify key model inputs. A modeling approach using the EPA's Stochastic Human Exposure and Dose Simulation (SHEDS)-Multimedia and Integrated Exposure Uptake and Biokinetic (IEUBK) models was developed using available data. This analysis for the U.S. population of young children probabilistically simulated multimedia exposures and estimated relative contributions of media to BLLs across all population percentiles for several age groups. Modeled BLLs compared well with nationally representative BLLs (0-23% relative error). Analyses revealed relative importance of soil and dust ingestion exposure pathways and associated Pb intake rates; water ingestion was also a main pathway, especially for infants. This methodology advances scientific understanding of the relationship between lead concentrations in drinking water and BLLs in children. It can guide national health-based benchmarks for lead and related community public health decisions. https://doi.org/10.1289/EHP1605.

E-Waste Informal Recycling: An Emerging Source of Lead Exposure in South America.

PubMed

Pascale, Antonio; Sosa, Adriana; Bares, Cristina; Battocletti, Alejandra; Moll, María José; Pose, Darío; Laborde, Amalia; González, Hugo; Feola, Gabriella

2016-01-01

Primitive electronic waste (e-waste) recycling creates exposures to several hazardous substances including lead. In Uruguay, primitive recycling procedures are a significant source of lead exposure. The aim of this study was to examine lead exposure in blood lead levels (BLLs) in low-income children exposed to lead through burning cables. A sample of children and adolescents exposed to lead through burning cable activities were assessed at the Department of Toxicology in Montevideo, Uruguay, between 2010 and 2014. Soil lead levels of residences were taken shortly after their assessment. The final sample included 69 children and adolescents (mean age 7.89 years). More than 66% of participants had an additional source of lead exposure-manual gathering of metals-and <5% were exposed to lead through landfills or paint. Average BLLs at first consultation were 9.19 ug/dL and lower at the second measurement (5.86 μg/dL). Data from soil lead levels ranged from 650 to 19,000 mg of lead/kg of soil. The interventions conducted after the assessment included family education in the clinic and at home, indoor and outdoor remediation. We found a decrease in BLLs of 6.96 μg/dL. Older children had lower BLLs (r = -0.24; P = 0.05). Statistical analyses also showed that children living in areas with higher soil lead levels had significantly higher BLLs (r = 0.50; P < 0.01). Additionally, we found greater BLLs from burning cable activities when children had been exposed to lead-based paint (r = 0.23; P < 0.1). Among children exposed to e-waste recycling, the most common additional source of lead exposure was the manual gathering of metals. The average BLL among children and adolescents in this study is higher than the BLLs currently suggested in medical intervention. Future research should focus on exploring effective interventions to reduce lead exposure among this vulnerable group. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

A Review of Non-Chemical Stressors and Their Importance in Cumulative Risk Assessment

EPA Science Inventory

Cumulative exposure/risk assessments need to include non-chemical stressors as well as human activities and chemical data. Multiple stressor research can offer information on the interactions between chemical and non-chemical stressors needed for cumulative risk assessment resea...

Characterizing Golden Eagle risk to lead and anticoagulant rodenticide exposure: A review

USGS Publications Warehouse

Herring, Garth; Eagles-Smith, Collin A.; Buck, Jeremy A.

2017-01-01

Contaminant exposure is among the many threats to Golden Eagle (Aquila chrysaetos) populations throughout North America, particularly lead poisoning and anticoagulant rodenticides (AR). These threats may act in concert with others (e.g., lead poisoning and trauma associated with striking objects) to exacerbate risk. Golden Eagles are skilled hunters but also exploit scavenging opportunities, making them particularly susceptible to contaminant exposure from ingesting tissues of poisoned or shot animals. Lead poisoning has long been recognized as an important source of mortality for Golden Eagles throughout North America. More recently, ARs have been associated with both sublethal and lethal effects in raptor species worldwide. In this review, we examine the current state of knowledge for lead and AR exposure in Golden Eagles, drawing from the broader raptor contaminant ecology literature. We examine lead and AR sources within Golden Eagle habitats, exposure routes and toxicity, effects on individuals and populations, synergistic effects, and data and information needs. Continued research addressing data needs and information gaps will help with Golden Eagle conservation planning.

Chronic Noise Exposure Acts Cumulatively to Exacerbate Alzheimer’s Disease-Like Amyloid-β Pathology and Neuroinflammation in the Rat Hippocampus

PubMed Central

Cui, Bo; Li, Kang; Gai, Zhihui; She, Xiaojun; Zhang, Na; Xu, Chuanxiang; Chen, Xuewei; An, Gaihong; Ma, Qiang; Wang, Rui

2015-01-01

A putative etiological association exists between noise exposure and Alzheimer’s disease (AD). Amyloid-β (Aβ) pathology is thought to be one of the primary initiating factors in AD. It has been further suggested that subsequent dysregulation of Aβ may play a mechanistic role in the AD-like pathophysiology associated with noise exposure. Here, we used ELISA, immunoblotting, cytokine arrays, and RT-PCR, to examine both hippocampal Aβ pathology and neuroinflammation in rats at different time points after noise exposure. We found that chronic noise exposure significantly accelerated the progressive overproduction of Aβ, which persisted for 7 to 14 days after the cessation of exposure. This effect was accompanied by up-regulated expression of amyloid precursor protein (APP) and its cleavage enzymes, β- and γ-secretases. Cytokine analysis revealed that chronic noise exposure increased levels of tumor necrosis factor-α and the receptor for advanced glycation end products, while decreasing the expression of activin A and platelet-derived growth factor- AA. Furthermore, we found persistent elevations of glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 expression that closely corresponded to the noise-induced increases in Aβ and neuroinflammation. These studies suggest that lifelong environmental noise exposure may have cumulative effects on the onset and development of AD. PMID:26251361

Sex-Dependent Effects of Developmental Lead Exposure on the Brain.

PubMed

Singh, Garima; Singh, Vikrant; Sobolewski, Marissa; Cory-Slechta, Deborah A; Schneider, Jay S

2018-01-01

The role of sex as an effect modifier of developmental lead (Pb) exposure has until recently received little attention. Lead exposure in early life can affect brain development with persisting influences on cognitive and behavioral functioning, as well as, elevated risks for developing a variety of diseases and disorders in later life. Although both sexes are affected by Pb exposure, the incidence, manifestation, and severity of outcomes appears to differ in males and females. Results from epidemiologic and animal studies indicate significant effect modification by sex, however, the results are not consistent across studies. Unfortunately, only a limited number of human epidemiological studies have included both sexes in independent outcome analyses limiting our ability to draw definitive conclusions regarding sex-differentiated outcomes. Additionally, due to various methodological differences across studies, there is still not a good mechanistic understanding of the molecular effects of lead on the brain and the factors that influence differential responses to Pb based on sex. In this review, focused on prenatal and postnatal Pb exposures in humans and animal models, we discuss current literature supporting sex differences in outcomes in response to Pb exposure and explore some of the ideas regarding potential molecular mechanisms that may contribute to sex-related differences in outcomes from developmental Pb exposure. The sex-dependent variability in outcomes from developmental Pb exposure may arise from a combination of complex factors, including, but not limited to, intrinsic sex-specific molecular/genetic mechanisms and external risk factors including sex-specific responses to environmental stressors which may act through shared epigenetic pathways to influence the genome and behavioral output.

Sex-Dependent Effects of Developmental Lead Exposure on the Brain

PubMed Central

Singh, Garima; Singh, Vikrant; Sobolewski, Marissa; Cory-Slechta, Deborah A.; Schneider, Jay S.

2018-01-01

The role of sex as an effect modifier of developmental lead (Pb) exposure has until recently received little attention. Lead exposure in early life can affect brain development with persisting influences on cognitive and behavioral functioning, as well as, elevated risks for developing a variety of diseases and disorders in later life. Although both sexes are affected by Pb exposure, the incidence, manifestation, and severity of outcomes appears to differ in males and females. Results from epidemiologic and animal studies indicate significant effect modification by sex, however, the results are not consistent across studies. Unfortunately, only a limited number of human epidemiological studies have included both sexes in independent outcome analyses limiting our ability to draw definitive conclusions regarding sex-differentiated outcomes. Additionally, due to various methodological differences across studies, there is still not a good mechanistic understanding of the molecular effects of lead on the brain and the factors that influence differential responses to Pb based on sex. In this review, focused on prenatal and postnatal Pb exposures in humans and animal models, we discuss current literature supporting sex differences in outcomes in response to Pb exposure and explore some of the ideas regarding potential molecular mechanisms that may contribute to sex-related differences in outcomes from developmental Pb exposure. The sex-dependent variability in outcomes from developmental Pb exposure may arise from a combination of complex factors, including, but not limited to, intrinsic sex-specific molecular/genetic mechanisms and external risk factors including sex-specific responses to environmental stressors which may act through shared epigenetic pathways to influence the genome and behavioral output. PMID:29662502

Mapping the spatio-temporal risk of lead exposure in apex species for more effective mitigation

PubMed Central

Mateo-Tomás, Patricia; Olea, Pedro P.; Jiménez-Moreno, María; Camarero, Pablo R.; Sánchez-Barbudo, Inés S.; Rodríguez Martín-Doimeadios, Rosa C.; Mateo, Rafael

2016-01-01

Effective mitigation of the risks posed by environmental contaminants for ecosystem integrity and human health requires knowing their sources and spatio-temporal distribution. We analysed the exposure to lead (Pb) in griffon vulture Gyps fulvus—an apex species valuable as biomonitoring sentinel. We determined vultures' lead exposure and its main sources by combining isotope signatures and modelling analyses of 691 bird blood samples collected over 5 years. We made yearlong spatially explicit predictions of the species risk of lead exposure. Our results highlight elevated lead exposure of griffon vultures (i.e. 44.9% of the studied population, approximately 15% of the European, showed lead blood levels more than 200 ng ml−1) partly owing to environmental lead (e.g. geological sources). These exposures to environmental lead of geological sources increased in those vultures exposed to point sources (e.g. lead-based ammunition). These spatial models and pollutant risk maps are powerful tools that identify areas of wildlife exposure to potentially harmful sources of lead that could affect ecosystem and human health. PMID:27466455

A comparison of the diminution rates of lead in blood and lead mobilized by CaEDTA after termination of occupational exposure: a long-term observation in two lead workers.

PubMed

Araki, S; Murata, K; Aono, H; Yanagihara, S; Ushio, K

1983-07-01

CaEDTA 20 mg/kg was administered weekly for 3.5 years after termination of occupational exposure to two lead workers. The diminution half-lives for lead in blood and urine lead mobilized by CaEDTA were 4.8 and 3.3 years respectively for subject 1 following 28 years exposure and 3.3 and 2.0 years respectively for subject 2 following 26 years exposure. The difference in the diminution rate between lead in blood and lead mobilized by CaEDTA was significant in subject 2 (p less than 0.05).

Lead exposure affects health indices in free-ranging ducks in Argentina.

PubMed

Ferreyra, Hebe; Beldomenico, Pablo M; Marchese, Krysten; Romano, Marcelo; Caselli, Andrea; Correa, Ana I; Uhart, Marcela

2015-05-01

Numerous experiments under controlled conditions and extensive investigation of waterfowl die-offs have demonstrated that exposure to lead from spent gunshot is highly detrimental to the health of waterfowl. However, few studies have focused on examining the more subtle sub-lethal effects of lead toxicity on ducks in non-experimental settings. In our study, the health of ducks exposed to varying amounts of lead under natural conditions was assessed by correlating individual lead exposure with relevant indices of health. Based on hunter-killed wild ducks in Argentina, we measured spleen mass, body condition, examined bone marrow smears, and determined Ca and P in bone tissue. In free-ranging live-trapped ducks we determined basic hematology and aminolevulinic acid dehydratase activity. Using multivariate analyses, we found that, when controlling for the potential confounding effect of site type, year, duck species, body mass and age, lead levels in the liver were negatively associated with body condition and spleen mass. Spleen mass was also lower in ducks with higher lead levels in their bones. In live ducks, high blood lead levels were associated with low packed cell volume and red cell morphologic abnormalities. These findings suggest that, despite the lack of recorded lead-induced mortality in the region, lead exposure results in less conspicuous but still significant impacts on the health of ducks, which could have serious implications for their conservation. Moreover, this evidence further supports the need for urgently banning lead shot in the region.

Sublethal Lead Exposure Alters Movement Behavior in Free-Ranging Golden Eagles.

PubMed

Ecke, Frauke; Singh, Navinder J; Arnemo, Jon M; Bignert, Anders; Helander, Björn; Berglund, Åsa M M; Borg, Hans; Bröjer, Caroline; Holm, Karin; Lanzone, Michael; Miller, Tricia; Nordström, Åke; Räikkönen, Jannikke; Rodushkin, Ilia; Ågren, Erik; Hörnfeldt, Birger

2017-05-16

Lead poisoning of animals due to ingestion of fragments from lead-based ammunition in carcasses and offal of shot wildlife is acknowledged globally and raises great concerns about potential behavioral effects leading to increased mortality risks. Lead levels in blood were correlated with progress of the moose hunting season. Based on analyses of tracking data, we found that even sublethal lead concentrations in blood (25 ppb, wet weight), can likely negatively affect movement behavior (flight height and movement rate) of free-ranging scavenging Golden Eagles (Aquila chrysaetos). Lead levels in liver of recovered post-mortem analyzed eagles suggested that sublethal exposure increases the risk of mortality in eagles. Such adverse effects on animals are probably common worldwide and across species, where game hunting with lead-based ammunition is widespread. Our study highlights lead exposure as a considerably more serious threat to wildlife conservation than previously realized and suggests implementation of bans of lead ammunition for hunting.

A Framework for Widespread Replication of a Highly Spatially Resolved Childhood Lead Exposure Risk Model

PubMed Central

Kim, Dohyeong; Galeano, M. Alicia Overstreet; Hull, Andrew; Miranda, Marie Lynn

2008-01-01

Background Preventive approaches to childhood lead poisoning are critical for addressing this longstanding environmental health concern. Moreover, increasing evidence of cognitive effects of blood lead levels < 10 μg/dL highlights the need for improved exposure prevention interventions. Objectives Geographic information system–based childhood lead exposure risk models, especially if executed at highly resolved spatial scales, can help identify children most at risk of lead exposure, as well as prioritize and direct housing and health-protective intervention programs. However, developing highly resolved spatial data requires labor-and time-intensive geocoding and analytical processes. In this study we evaluated the benefit of increased effort spent geocoding in terms of improved performance of lead exposure risk models. Methods We constructed three childhood lead exposure risk models based on established methods but using different levels of geocoded data from blood lead surveillance, county tax assessors, and the 2000 U.S. Census for 18 counties in North Carolina. We used the results to predict lead exposure risk levels mapped at the individual tax parcel unit. Results The models performed well enough to identify high-risk areas for targeted intervention, even with a relatively low level of effort on geocoding. Conclusions This study demonstrates the feasibility of widespread replication of highly spatially resolved childhood lead exposure risk models. The models guide resource-constrained local health and housing departments and community-based organizations on how best to expend their efforts in preventing and mitigating lead exposure risk in their communities. PMID:19079729

Environmental and Occupational Lead Exposure Among Children in Cairo, Egypt

PubMed Central

Moawad, Eman Mohamed Ibraheim; Badawy, Nashwa Mostafa; Manawill, Marie

2016-01-01

Abstract The aim of this study was to assess childhood lead exposure in a representative sample of Cairo, and to investigate the possible risk factors and sources of exposure. This cross-sectional study was conducted from November 2014 through April 2015. The target population was children aged 6 to 18 years, recruited into 4 groups, garbage city, moderate-living standard area, urban and suburban schools, and workshops in the city of Cairo. Blood lead levels (BLLs) and hemoglobin (Hb) concentrations were measured. Also, potential local environmental sources were assessed for hazardous lead contamination. Analysis on 400 participants has been carried out. A total of 113 children had BLLs in the range 10 to 20 μg/dL. Smoking fathers, housing conditions, playing outdoors, and exposure to lead in residential areas were significantly correlated with high BLLs. The mean values of hemoglobin were inversely correlated with BLLs. Children involved in pottery workshops had the highest BLLs and the lowest Hb values with a mean of (43.3 μg/dL and 8.6 g/dL, respectively). The mean value of environmental lead in workshop areas exceeded the recommended levels. Also, those values measured in dust and paint samples of garbage city were significantly high. Moreover, the mean lead levels in the soil samples were significantly higher in urban schools (P = 0.03) than the suburban ones. Childhood lead poisoning accounts for a substantial burden in Egypt, which could be preventable. Development of national prevention programs including universal screening program should be designed to reduce incidence of lead toxicity among children. PMID:26945415

Elevated blood lead levels from exposure via a radiator workshop.

PubMed

Treble, R G; Thompson, T S; Morton, D N

1998-04-01

Elevated lead levels were discovered in blood samples collected from family members where both the father and the mother worked in a radiator repair workshop. The father and mother were found to have blood lead levels of 2.0 and 0.5 mumol/L (41.7 and 10.4 micrograms/dL), respectively. The father's blood lead level was just below the Canadian occupational health and safety intervention level (2.5 mumol/L or 52.1 micrograms/dL). The two children had blood lead levels of 1.0 and 0.8 mumol/L (20.8 and 16.7 micrograms/dL), both of which are in excess of the recommended guideline for intervention in the case of children (0.5 mumol/L or 10.4 micrograms/dL). The exposure of the two children was possibly due to a combination of pathways including exposure at the workshop itself during visits and also the transportation of lead-containing dust to the home environment.

Unintentional and Sequential Lead Exposure from a Ceramic Mug and Maca (Lepidium meyenii).

PubMed

Johnson-Arbor, Kelly; Vo, Kathy; Wong, Flavia; Gajek, Ryszard

2018-06-01

Although the incidence of lead poisoning has decreased in the USA over the last 30 years, human exposures to lead-containing products are still reported. We present a case of unintentional lead exposure from a store-bought ceramic mug and a nutritional supplement. A 32-year-old female was found to have a whole blood lead concentration of 44 μg/dL. Evaluation of her home, occupation, and hobbies initially did not identify a source of lead exposure. Further investigation revealed that the likely etiology of the exposure was lead leaching from a ceramic mug used by the patient to drink hot lemon water while she was pregnant. She stopped drinking from the mug and her blood lead levels decreased, but increased a year later after she began to ingest a maca root powder supplement. Upon discontinuation of maca root powder ingestion, her blood lead levels decreased further. Over time, the acidity and heat of the hot lemon water used in the ceramic mug enhanced the breakdown of its leaded glaze. Maca powder, which is available as a nutritional supplement and is used to treat fatigue and enhance fertility, may contain lead and other minerals. Consumers, particularly women of childbearing age, and their physicians should be aware that imported products available from commercial retailers and internet vendors may contain significant amounts of lead.

Primary prevention of pediatric lead exposure requires new approaches to transfusion screening.

PubMed

Gehrie, Eric; Keiser, Amaris; Dawling, Sheila; Travis, James; Strathmann, Frederick G; Booth, Garrett S

2013-09-01

To facilitate further assessment of transfusion-associated lead exposure by designing a procedure to test packed red blood cells (pRBCs) prepared for transfusion. The relationship between pRBCs and whole blood lead concentration was investigated in 27 samples using a modified clinical assay. Lead concentrations were measured in 100 pRBC units. Our sample preparation method demonstrated a correlation between whole blood lead and pRBC lead concentrations (R(2) = 0.82). In addition, all 100 pRBC units tested had detectable lead levels. The median pRBC lead concentration was 0.8 μg/dL, with an SD of 0.8 μg/dL and a range of 0.2-4.1 μg/dL. In addition, after only a few days of storage, approximately 25% of whole blood lead was found in the supernatant plasma. Transfusion of pRBCs is a source of lead exposure. Here we report the quantification of lead concentration in pRBCs. We found a >20-fold range of lead concentrations in the samples tested. Pretransfusion testing of pRBC units according to our proposed approach or donor screening of whole blood lead and selection of below-average units for transfusion to children would diminish an easily overlooked source of pediatric lead exposure. Copyright © 2013 Mosby, Inc. All rights reserved.

Cumulative Stress and Cortisol Disruption among Black and Hispanic Pregnant Women in an Urban Cohort.

PubMed

Suglia, Shakira Franco; Staudenmayer, John; Cohen, Sheldon; Enlow, Michelle Bosquet; Rich-Edwards, Janet W; Wright, Rosalind J

2010-12-01

While adult hypothalamic-pituitary-adrenocortical (HPA) axis functioning is thought to be altered by traumatic experiences, little data exist on the effects of cumulative stress on HPA functioning among pregnant women or among specific racial and ethnic groups. Individuals may be increasingly vulnerable to physiological alterations when experiencing cumulative effects of multiple stressors. These effects may be particularly relevant in urban poor communities where exposure to multiple stressors is more prevalent. The goal of this study was to explore the effects of multiple social stressors on HPA axis functioning in a sample of urban Black (n = 68) and Hispanic (n = 132) pregnant women enrolled in the Asthma Coalition on Community, Environment, and Social Stress (ACCESS). Pregnant women were administered the Revised Conflict Tactics Scale (R-CTS) survey to assess interpersonal violence, the Experiences of Discrimination (EOD) survey, the Crisis in Family Systems-Revised (CRISYS-R) negative life events survey, and the My Exposure to Violence (ETV) survey, which ascertains exposure to community violence. A cumulative stress measure was derived from these instruments. Salivary cortisol samples were collected five times per day over three days to assess area under the curve (AUC), morning change, and basal awakening response in order to characterize diurnal salivary cortisol patterns. Repeated measures mixed models, stratified by race/ethnicity, were performed adjusting for education level, age, smoking status, body mass index and weeks pregnant at time of cortisol sampling. The majority of Hispanic participants (57%) had low cumulative stress exposure, while the majority of Black participants had intermediate (35%) or high (41%) cumulative stress exposure. Results showed that among Black but not Hispanic women, cumulative stress was associated with lower morning cortisol levels, including a flatter waking to bedtime rhythm. These analyses suggest that the combined

Risk of cardiovascular events from current, recent, and cumulative exposure to abacavir among persons living with HIV who were receiving antiretroviral therapy in the United States: a cohort study.

PubMed

Dorjee, Kunchok; Baxi, Sanjiv M; Reingold, Arthur L; Hubbard, Alan

2017-10-27

There is ongoing controversy regarding abacavir use in the treatment of HIV infection and the risk of subsequent development of cardiovascular disease. It is unclear how the risk varies as exposure accumulates. Using an administrative health-plan dataset, risk of cardiovascular disease events (CVDe), defined as the first episode of an acute myocardial infarction or a coronary intervention procedure, associated with abacavir exposure was assessed among HIV-infected individuals receiving antiretroviral therapy across the U.S. from October 2009 through December 2014. The data were longitudinal, and analyzed using marginal structural models. Over 114,470 person-years (n = 72,733) of ART exposure, 714 CVDe occurred at an incidence rate (IR) (95% CI) of 6·23 (5·80, 6·71)/1000 person-years. Individuals exposed to abacavir had a higher IR of CVDe of 9·74 (8·24, 11·52)/1000 person-years as compared to 5·75 (5·30, 6·24)/1000 person-years for those exposed to other antiretroviral agents. The hazard (HR; 95% CI) of CVDe was increased for current (1·43; 1·18, 1·73), recent (1·41; 1·16, 1·70), and cumulative [(1·18; 1·06, 1·31) per year] exposure to abacavir. The risk for cumulative exposure followed a bell-shaped dose-response curve peaking at 24-months of exposure. Risk was similarly elevated among participants free of pre-existing heart disease or history of illicit substance use at baseline. Current, recent, and cumulative use of abacavir was associated with an increased risk of CVDe. The findings were consistent irrespective of underlying cardiovascular risk factors.

The Effects of Cumulative Violence Clusters on Young Mothers' School Participation: Examining Attention and Behavior Problems as Mediators.

PubMed

Kennedy, Angie C; Adams, Adrienne E

2016-04-01

Using a cluster analysis approach with a sample of 205 young mothers recruited from community sites in an urban Midwestern setting, we examined the effects of cumulative violence exposure (community violence exposure, witnessing intimate partner violence, physical abuse by a caregiver, and sexual victimization, all with onset prior to age 13) on school participation, as mediated by attention and behavior problems in school. We identified five clusters of cumulative exposure, and found that the HiAll cluster (high levels of exposure to all four types) consistently fared the worst, with significantly higher attention and behavior problems, and lower school participation, in comparison with the LoAll cluster (low levels of exposure to all types). Behavior problems were a significant mediator of the effects of cumulative violence exposure on school participation, but attention problems were not. © The Author(s) 2014.

Reasons for testing and exposure sources among women of childbearing age with moderate blood lead levels.

PubMed

Fletcher, A M; Gelberg, K H; Marshall, E G

1999-06-01

The purpose of this study was to examine the circumstances under which women receive blood lead tests in New York State and to characterize the sources of lead exposure among women of childbearing age with moderate blood lead levels. Telephone interviews were conducted with 135 women between the ages of 18 and 45, with blood lead levels from 10 through 25 micrograms/dl, were used to collect information on the reason for their blood lead test and possible sources of lead exposure. It was found that the two most common reasons to be tested for blood lead were workplace screening (47%) and pregnancy (27%). Occupational exposure was the primary source of lead exposure in this population (46%). Another common source of lead exposure was home renovation (24%). A significant proportion (31%) of women with blood lead levels from 10 through 25 micrograms/dl had no known current source of lead exposure. Based on New York's sample, there are a significant number of women of reproductive age with potentially fetotoxic blood lead levels.

A Psychoneuroimmunologic Examination of Cumulative Perinatal Steroid Exposures and Preterm Infant Behavioral Follow-Up

PubMed Central

Purdy, Isabell B.; Smith, Lynne; Wiley, Dorothy; Badr, Lina

2014-01-01

Purpose This study’s aim was to explore relationships between preterm infant behavioral outcomes and maternal/infant glucocorticoid (dexamethasone [DEX]) treatments using a psychoneuroimmunologic approach. Research questions were (a) do relationships exist between infant cumulative perinatal steroid (PNS) exposure and child behavioral problems? and (b) do maternal/infant characteristics (e.g., immune markers and biophysiologic stressors) influence these relationships? Methods The convenience sample comprised 45 mother–child dyads in which the children (mean age 8 years ± 2.3) had been born at a mean postconceptional age of 28 weeks (± 4.2). We used the Child Behavior Checklist (CBCL) to assess behavior, the Clinical Risk Index for Babies (CRIB) to score stress at birth, and retrospective record review to identify additional perinatal factors (PNS dosage, sepsis, and maternal and infant complete blood counts near delivery). Results Children were dichotomized into high (> 0.2mg/kg; n = 20) versus low–no (≤ 0.2 mg/kg; n = 25) PNS exposure groups. Significant relationships existed between CBCL Total Problems score and sepsis, PNS exposure, timing of initial PNS, and infant length percentile at discharge. Competence problems were significantly associated with PNS, neonatal intensive care unit (NICU) infant length percentile, CRIB score, sepsis, retinopathy of prematurity, hearing deficit, and immunity markers (i.e., maternal lymphocyte percentage and infant band/seg ratio). Children in the higher PNS group exhibited more behavioral problems (e.g., withdrawn, attention, conduct, social, and rule breaking problems), but there were no significant differences. The findings are reassuring regarding long-term effects of this PNS dose on preterm infant behavioral outcomes. PMID:21900308

Cumulative Risk and Impact Modeling on Environmental Chemical and Social Stressors.

PubMed

Huang, Hongtai; Wang, Aolin; Morello-Frosch, Rachel; Lam, Juleen; Sirota, Marina; Padula, Amy; Woodruff, Tracey J

2018-03-01

The goal of this review is to identify cumulative modeling methods used to evaluate combined effects of exposures to environmental chemicals and social stressors. The specific review question is: What are the existing quantitative methods used to examine the cumulative impacts of exposures to environmental chemical and social stressors on health? There has been an increase in literature that evaluates combined effects of exposures to environmental chemicals and social stressors on health using regression models; very few studies applied other data mining and machine learning techniques to this problem. The majority of studies we identified used regression models to evaluate combined effects of multiple environmental and social stressors. With proper study design and appropriate modeling assumptions, additional data mining methods may be useful to examine combined effects of environmental and social stressors.

Prenatal lead exposure modifies the impact of maternal self-esteem on children's inattention behavior

PubMed Central

Xu, Jian; Hu, Howard; Wright, Rosalind; Sánchez, Brisa N.; Schnaas, Lourdes; Bellinger, David C.; Park, Sung Kyun; Martínez, Sandra; Hernández-Avila, Mauricio; Téllez-Rojo, Martha Maria; Wright, Robert O.

2015-01-01

Objective To prospectively evaluate the association of maternal self-esteem measured when their offspring were toddlers with the subsequent development of attention-deficit-hyperactivity-disorder (ADHD)-like behavior in their school-age offspring and the potential modifying effects of prenatal lead exposure. Study design We evaluated a subsample of 192 mother-child pairs from a long-running birth-cohort project that enrolled mothers in Mexico from 1994 to 2011. Prenatal lead exposure was assessed using cord blood lead and maternal bone lead around delivery (tibia and patella lead, measured by K-x-ray-fluorescence). When children were 2 years old, maternal self-esteem was measured using the Coopersmith-Self-esteem-Inventory. When children were 7-to-15 years old, children's blood lead levels and ADHD symptoms were assessed, and Conners’ Parental-Rating-Scales-Revised (CPRS-R) and Behavior-Rating-Inventory-of-Executive-Function-Parent Form (BRIEF-P) were used as measures of ADHD-like behavior. Results Adjusting for family economic status, marital status, maternal education and age, child's age and sex, and children's current blood lead levels, increased maternal self-esteem was associated with reduced child inattention behavior. Compared with those among high prenatal lead exposure (P25-P100), this association was stronger among low prenatal lead exposure groups (P1-P25, p-values for the interaction effects between prenatal lead exposure and maternal self-esteem levels < 0.10). Each 1-point increase in maternal self-esteem scores was associated with 0.6-to-1.3-point decrease in CPRS-R and BRIEF-P T-scores among groups with low cord blood lead and patella lead (P1-P25). Conclusions Children experiencing high maternal self-esteem during toddlerhood were less likely to develop inattention behavior at school-age. Prenatal lead exposure may play a role in attenuating this protective effect. PMID:26047683

Prenatal Lead Exposure Modifies the Impact of Maternal Self-Esteem on Children's Inattention Behavior.

PubMed

Xu, Jian; Hu, Howard; Wright, Rosalind; Sánchez, Brisa N; Schnaas, Lourdes; Bellinger, David C; Park, Sung Kyun; Martínez, Sandra; Hernández-Avila, Mauricio; Téllez-Rojo, Martha Maria; Wright, Robert O

2015-08-01

To prospectively evaluate the association of maternal self-esteem measured when their offspring were toddlers with the subsequent development of attention deficit hyperactivity disorder (ADHD)-like behavior in their school-age offspring and the potential modifying effects of prenatal lead exposure. We evaluated a subsample of 192 mother-child pairs from a long-running birth-cohort project that enrolled mothers in Mexico from 1994-2011. Prenatal lead exposure was assessed using cord blood lead and maternal bone lead around delivery (tibia and patella lead, measured by K-x-ray-fluorescence). When children were 2 years old, maternal self-esteem was measured using the Coopersmith Self-Esteem Inventory. When children were 7-15 years old, children's blood lead levels and ADHD symptoms were assessed, and Conners' Parent Rating Scale-Revised and Behavior Rating Inventory of Executive Function-Parent Form were used as measures of ADHD-like behavior. Adjusting for family economic status, marital status, maternal education and age, child's age and sex, and children's current blood lead levels, increased maternal self-esteem was associated with reduced child inattention behavior. Compared with those among high prenatal lead exposure (P25-P100), this association was stronger among low prenatal lead exposure groups (P1-P25, P values for the interaction effects between prenatal lead exposure and maternal self-esteem levels of <.10). Each 1-point increase in maternal self-esteem scores was associated with 0.6- to 1.3-point decrease in Conners' Parent Rating Scale-Revised and Behavior Rating Inventory of Executive Function-Parent Form T-scores among groups with low cord blood lead and patella lead (P1-P25). Children experiencing high maternal self-esteem during toddlerhood were less likely to develop inattention behavior at school age. Prenatal lead exposure may play a role in attenuating this protective effect. Copyright © 2015 Elsevier Inc. All rights reserved.

An application of the Aggregate Exposure Pathway (AEP) and Adverse Outcome Pathway (AOP) frameworks to mechanistically integrate data sources across multiple species into cumulative risk assessment (CRA)

EPA Science Inventory

Toxicologists use dose-response data from both in vivo and in vitro experiments to evaluate the effects of chemical contaminants on organisms. Cumulative risk assessments (CRAs) consider the effects of multiple stressors on multiple endpoints, and utilize environmental exposure ...

[The influence of occupational lead exposure on transmural repolarization dispersion].

PubMed

Zyśko, Dorota; Gajek, Jacek; Chlebda, Ewa; Mazurek, Walentyna

2005-02-01

The parts of QT interval: time from Q wave to the peak of T wave (QTp) representing the de- and repolarization of subepicardial layer and the time from the peak of T wave to its end (QTp-e) building the transmural dispersion of repolarization enable more exact assessment of repolarization period of the heart muscle. Occupational exposure to lead influences the electrophysiologic properties of the heart. The aim of our study was to assess the QTp and QTp-e interval in workers occupationally exposed to lead. The study was carried out in 22 copper smelters aged 41.8 +/- 8.7 years, occupationally exposed to lead. The control group consisted of 14 healthy men. In all studied subjects blood lead concentration (Pb) and the concentration of free protoporphyrins in erytrocytes were assessed. 24-hour ECG holter monitoring was done to study rhythm disturbances and the duration in lead CM5 of QT interval, QTp interval, RR interval preceding the assessed QT interval (pRR) during sleep, rest during the awake state and moderate daily activity. The QTp-e interval is the difference between the duration of QT and QTp interval. The duration of QTp and QTp-e in occupationally exposed workers and healthy persons did not differ significantly. These parameters were significantly lower in both groups during moderately physical activity comparing to the values during sleep. The QTp-e/ QTp ratio in occupationally exposed workers during night hours was significantly lower than during daily activity what was not the case in control persons. Occupational exposure to lead do not change significantly the transmural dispersion of repolarization. Occupational exposure to lead diminishes the QTp-e/QTp ratio during the night.

E-Waste Informal Recycling: An Emerging Source of Lead Exposure in South America

PubMed Central

Pascale, Antonio; Sosa, Adriana; Bares, Cristina; Battocletti, Alejandra; Moll, María José; Pose, Darío; Laborde, Amalia; González, Hugo; Feola, Gabriella

2016-01-01

BACKGROUND Primitive electronic waste (e-waste) recycling creates exposures to several hazardous substances including lead. In Uruguay, primitive recycling procedures are a significant source of lead exposure. OBJECTIVES The aim of this study was to examine lead exposure in blood lead levels (BLLs) in low-income children exposed to lead through burning cables. METHODS A sample of children and adolescents exposed to lead through burning cable activities were assessed at the Department of Toxicology in Montevideo, Uruguay, between 2010 and 2014. Soil lead levels of residences were taken shortly after their assessment. FINDINGS The final sample included 69 children and adolescents (mean age 7.89 years). More than 66% of participants had an additional source of lead exposure—manual gathering of metals—and <5% were exposed to lead through landfills or paint. Average BLLs at first consultation were 9.19 ug/dL and lower at the second measurement (5.86 μg/dL). Data from soil lead levels ranged from 650 to 19,000 mg of lead/kg of soil. The interventions conducted after the assessment included family education in the clinic and at home, indoor and outdoor remediation. We found a decrease in BLLs of 6.96 μg/dL. Older children had lower BLLs (r = −0.24; P =0.05). Statistical analyses also showed that children living in areas with higher soil lead levels had significantly higher BLLs (r = 0.50; P < 0.01). Additionally, we found greater BLLs from burning cable activities when children had been exposed to lead-based paint (r = 0.23; P < 0.1). CONCLUSION Among children exposed to e-waste recycling, the most common additional source of lead exposure was the manual gathering of metals. The average BLL among children and adolescents in this study is higher than the BLLs currently suggested in medical intervention. Future research should focus on exploring effective interventions to reduce lead exposure among this vulnerable group. PMID:27325077

Household interventions for preventing domestic lead exposure in children.

PubMed

Yeoh, Berlinda; Woolfenden, Susan; Lanphear, Bruce; Ridley, Greta F; Livingstone, Nuala; Jorgensen, Emile

2014-12-15

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children and trials have tested many household interventions to prevent lead exposure. This is an update of the original review by the same authors first published in 2008. To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development. We identified trials through electronic searches of CENTRAL (2012, Issue 1), MEDLINE (1948 to January Week 1 2012), EMBASE (1980 to Week 2 2012), CINAHL (1937 to January 2012), PsycINFO (1887 to January Week 2 2012), ERIC (1966 to January 2012), Sociological Abstracts (1952 to January 2012), Science Citation Index (1970 to 20 January 2012), ZETOC (20 January 2012), LILACS (20 January 2012), Dissertation Abstracts (late 1960s to January 2012), ClinicalTrials.gov (19 January 2012), Current Controlled Trials (19 January 2012), Australian New Zealand Clinical Trials Registry (19 January 2012) and the National Research Register Archive. We also contacted experts to find unpublished studies. Randomised and quasi-randomised controlled trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported. Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We included 14 studies (involving 2656 children). All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. We put studies into subgroups according to their intervention type. We performed meta-analysis of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval

Household interventions for preventing domestic lead exposure in children.

PubMed

Yeoh, Berlinda; Woolfenden, Susan; Lanphear, Bruce; Ridley, Greta F; Livingstone, Nuala

2012-04-18

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children and trials have tested many household interventions to prevent lead exposure. This is an update of the original review by the same authors first published in 2008. To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development. We identified trials through electronic searches of CENTRAL (The Cochrane Library, 2010, Issue 2), MEDLINE (1948 to April Week 1 2012), EMBASE (1980 to 2012 Week 2), CINAHL (1937 to 20 Jan 2012), PsycINFO (1887 to Dec week 2 2011), ERIC (1966 to 17 Jan 2012), Sociological Abstracts (1952 to 20 January 2012), Science Citation Index (1970 to 20 Jan 2012), ZETOC (20 Jan 2012), LILACS (20 Jan 2012), Dissertation Abstracts (late 1960s to Jan 2012), ClinicalTrials.gov (20 Jan 2012), Current Controlled Trials (Jan 2012), Australian New Zealand Clinical Trials Registry (Jan 2012) and the National Research Register Archive. We also contacted experts to find unpublished studies. Randomised and quasi-randomised controlled trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported. Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We included 14 studies (involving 2656 children). All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. We put studies into subgroups according to their intervention type. We performed meta-analysis of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0

Cumulative effects of forest management activities: how might they occur?

Treesearch

R. M. Rice; R. B. Thomas

1985-01-01

Concerns are often voiced about possible environmental damage as the result of the cumulative sedimentation effects of logging and forest road construction. In response to these concerns, National Forests are developing procedures to reduce the possibility that their activities may lead to unacceptable cumulative effects

Specific factors for prenatal lead exposure in the border area of China.

PubMed

Kawata, Kimiko; Li, Yan; Liu, Hao; Zhang, Xiao Qin; Ushijima, Hiroshi

2006-07-01

The objectives of this study are to examine the prevalence of increased blood lead concentrations in mothers and their umbilical cords, and to identify risk factors for prenatal lead exposure in Kunming city, Yunnan province, China. The study was conducted at two obstetrics departments, and 100 peripartum women were enrolled. The mean blood lead concentrations of the mothers and the umbilical cords were 67.3microg/l and 53.1microg/l, respectively. In multiple linear regression analysis, maternal occupational exposure, maternal consumption of homemade dehydrated vegetables and maternal habitation period in Kunming city were significantly associated with an increase of umbilical cord blood lead concentration. In addition, logistic regression analysis was used to assess the association of umbilical cord blood lead concentrations that possibly have adverse effects on brain development of newborns with each potential risk factor. Maternal frequent use of tableware with color patterns inside was significantly associated with higher cord blood lead concentration in addition to the three items in the multiple linear regression analysis. These points should be considered as specific recommendations for maternal and fetal lead exposure in this city.

A pebble count procedure for assessing watershed cumulative effects

Treesearch

Gregory S. Bevenger; Rudy M. King

1995-01-01

Land mangement activities can result in the delivery of fine sediment to streams. Over time, such delivery can lead to cumulative impacts to the aquactic ecosystem. Because numerous laws require Federal land managers to analyze watershed cumulative effects, field personnel need simple monitoring procedures that can be used directly and consistently. One approach to...

Instrumental variables estimation of exposure effects on a time-to-event endpoint using structural cumulative survival models.

PubMed

Martinussen, Torben; Vansteelandt, Stijn; Tchetgen Tchetgen, Eric J; Zucker, David M

2017-12-01

The use of instrumental variables for estimating the effect of an exposure on an outcome is popular in econometrics, and increasingly so in epidemiology. This increasing popularity may be attributed to the natural occurrence of instrumental variables in observational studies that incorporate elements of randomization, either by design or by nature (e.g., random inheritance of genes). Instrumental variables estimation of exposure effects is well established for continuous outcomes and to some extent for binary outcomes. It is, however, largely lacking for time-to-event outcomes because of complications due to censoring and survivorship bias. In this article, we make a novel proposal under a class of structural cumulative survival models which parameterize time-varying effects of a point exposure directly on the scale of the survival function; these models are essentially equivalent with a semi-parametric variant of the instrumental variables additive hazards model. We propose a class of recursive instrumental variable estimators for these exposure effects, and derive their large sample properties along with inferential tools. We examine the performance of the proposed method in simulation studies and illustrate it in a Mendelian randomization study to evaluate the effect of diabetes on mortality using data from the Health and Retirement Study. We further use the proposed method to investigate potential benefit from breast cancer screening on subsequent breast cancer mortality based on the HIP-study. © 2017, The International Biometric Society.

Cumulative life stress in chronic fatigue syndrome.

PubMed

Nater, Urs M; Maloney, Elizabeth; Heim, Christine; Reeves, William C

2011-09-30

We studied the impact of cumulative life stress on CFS in a population-based study. We found that exposure to stressors was significantly more common in persons with CFS compared to NF controls; those with CFS reported experiencing significantly higher levels of psychological distress. Also, post-traumatic stress disorder was significantly more common in people with CFS. These results not only corroborate findings from other studies but, importantly, extend those by: a) measuring a comprehensive spectrum of stress variables, b) for the first time presenting data on stress in a population-based study, thus minimizing the effects of recruitment bias, and c) diagnosing CFS by means of standardized, validated scales, thus allowing replication and extension of our findings. Stress may be an important factor in the pathophysiology of CFS. Consequently, future studies should provide a more detailed understanding of the processes that lead from stress to CFS using longitudinal designs. Published by Elsevier Ireland Ltd.

Acute Stress Symptoms in Seriously Injured Patients: Precipitating Versus Cumulative Trauma and the Contribution of Peritraumatic Distress.

PubMed

Briere, John; Dias, Colin P; Semple, Randye J; Scott, Catherine; Bigras, Noémie; Godbout, Natacha

2017-08-01

The relationship between type of trauma exposure, cumulative trauma, peritraumatic distress, and subsequent acute stress disorder (ASD) symptoms was examined prospectively in 96 individuals presenting with acute medical injuries to a Level 1 emergency/trauma department. Common precipitating traumas included motor vehicle-related events, stabbings, shootings, and physical assaults. At 2 to 3 weeks follow-up, 22.9% of participants had developed ASD. Univariate analysis revealed no relationship between type of precipitating trauma and ASD symptoms, whereas robust path analysis indicated direct effects of gender, lifetime cumulative trauma exposure, and peritraumatic distress. Peritraumatic distress did not mediate the association between cumulative trauma and symptoms, but did mediate the association between gender and symptomatology. These results, which account for 23.1% of the variance in ASD symptoms, suggest that ASD may be more due to cumulative trauma exposure than the nature of the precipitating trauma, but that cumulative trauma does not exert its primary effect by increasing peritraumatic distress to the most recent trauma. Copyright © 2017 International Society for Traumatic Stress Studies.

Multi-Omics Reveals that Lead Exposure Disturbs Gut Microbiome Development, Key Metabolites, and Metabolic Pathways.

PubMed

Gao, Bei; Chi, Liang; Mahbub, Ridwan; Bian, Xiaoming; Tu, Pengcheng; Ru, Hongyu; Lu, Kun

2017-04-17

Lead exposure remains a global public health issue, and the recent Flint water crisis has renewed public concern about lead toxicity. The toxicity of lead has been well established in a variety of systems and organs. The gut microbiome has been shown to be highly involved in many critical physiological processes, including food digestion, immune system development, and metabolic homeostasis. However, despite the key role of the gut microbiome in human health, the functional impact of lead exposure on the gut microbiome has not been studied. The aim of this study is to define gut microbiome toxicity induced by lead exposure in C57BL/6 mice using multiomics approaches, including 16S rRNA sequencing, whole genome metagenomics sequencing, and gas chromatography-mass spectrometry (GC-MS) metabolomics. 16S rRNA sequencing revealed that lead exposure altered the gut microbiome trajectory and phylogenetic diversity. Metagenomics sequencing and metabolomics profiling showed that numerous metabolic pathways, including vitamin E, bile acids, nitrogen metabolism, energy metabolism, oxidative stress, and the defense/detoxification mechanism, were significantly disturbed by lead exposure. These perturbed molecules and pathways may have important implications for lead toxicity in the host. Taken together, these results demonstrated that lead exposure not only altered the gut microbiome community structures/diversity but also greatly affected metabolic functions, leading to gut microbiome toxicity.

Cumulative Risk Exposure and Waist Circumference in Preschool-Aged Children: the Mediating Role of Television and Moderating Role of Sex.

PubMed

Grummon, Anna H; Vaughn, Amber; Jones, Deborah J; Ward, Dianne S

2017-08-01

Children exposed to multiple stressors are more likely to be overweight, but little is known about the mechanisms explaining this association. This cross-sectional study examined whether children exposed to multiple stressors had higher waist circumference, and whether this association was mediated through children's television time. Participants were 319 parent-child dyads. Children were 2-5 years old and had at least one overweight parent (BMI ≥ 25 kg/m 2 ). Data were collected at baseline of a larger childhood obesity prevention study and included information on psychosocial stressors (e.g., parenting stress), demographic stressors (e.g., low income), children's television time, and children's waist circumference. Two cumulative risk scores were created by summing stressors in each domain (demographic and psychosocial). Mediation and moderated mediation analyses were conducted. Indirect effects of both cumulative risk scores on waist circumference through television time were not significant; however, moderated mediation analyses found significant moderation by gender. The indirect effects of both risk scores on waist circumference through television time were significant and positive for girls, but near-zero for boys. Reducing television time should be explored as a strategy for buffering against the negative health effects of exposure to multiple stressors among girls. Longitudinal and intervention research is needed to confirm these results and to identify mediating factors between cumulative risk and body weight among boys.

Cumulative trauma, PTSD and dissociation among Ethiopian refugees in Israel.

PubMed

Finklestein, Michal; Solomon, Zahava

2009-01-01

The aim of this study was to examine the exposure of Ethiopian refugees to pre-, peri- and post-migration stressful events and their implications for both posttraumatic stress disorder (PTSD) and dissociation. A random sample (N = 478) of three groups of refugees took part in the research ("Moses" immigrants, 1984, n = 165; "Solomon" immigrants, 1991, n = 169; "Family Reunification" immigrants, 1995, n = 144). Exposure to stressful events and posttraumatic symptoms were assessed via the Harvard Trauma Questionnaire (HTQ). Post-migration difficulties were assessed via the Post Migration Living Difficulties (PMLD) scale. Dissociation was evaluated using the Dissociation Experience Scale (DES). Significant differences were found among the groups in the rates of PTSD (27%, 15%, and 26%, respectively), but no differences were found in dissociation. A significant relationship was found between PTSD symptoms and cumulative trauma among the three groups, but no such relationship was found between dissociation and cumulative trauma. The differences among the groups were discussed in light of the unique characteristics of cumulative trauma, PTSD and dissociation among Ethiopian refugees.

Lead exposure in adult males in urban Transvaal Province, South Africa during the apartheid era.

PubMed

Hess, Catherine A; Cooper, Matthew J; Smith, Martin J; Trueman, Clive N; Schutkowski, Holger

2013-01-01

Human exposure to lead is a substantial public health hazard worldwide and is particularly problematic in the Republic of South Africa given the country's late cessation of leaded petrol. Lead exposure is associated with a number of serious health issues and diseases including developmental and cognitive deficiency, hypertension and heart disease. Understanding the distribution of lifetime lead burden within a given population is critical for reducing exposure rates. Femoral bone from 101 deceased adult males living in urban Transvaal Province (now Gauteng Province), South Africa between 1960 and 1998 were analyzed for lead concentration by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Of the 72 black and 29 white individuals sampled, chronic lead exposure was apparent in nearly all individuals. White males showed significantly higher median bone lead concentration (ME = 10.04 µg·g(-1)), than black males (ME = 3.80 µg·g(-1)) despite higher socioeconomic status. Bone lead concentration covaries significantly, though weakly, with individual age. There was no significant temporal trend in bone lead concentration. These results indicate that long-term low to moderate lead exposure is the historical norm among South African males. Unexpectedly, this research indicates that white males in the sample population were more highly exposed to lead.

Lead exposure in young school children in South African subsistence fishing communities.

PubMed

Mathee, Angela; Khan, Taskeen; Naicker, Nisha; Kootbodien, Tahira; Naidoo, Shan; Becker, Piet

2013-10-01

Lead is an established toxic substance, with wide-ranging health effects, including neurodevelopmental decrements and behavioural problems, even at low levels in blood. Anecdotal reports of lead melting to make fishing sinkers in South African subsistence fishing communities prompted the conduct of an epidemiological study in two South African fishing villages to investigate the extent of lead melting and the associated risks in children. The objectives of the study were to determine the extent of lead melting, and the blood lead distributions and associated risk factors in children. Cross-sectional, analytical studies were undertaken among 160 young school children in the fishing villages of Struis Bay and Elands Bay located along the south-eastern and western South African coastline, respectively. Blood samples were collected for lead content analysis, and anthropometric and hemoglobin measurements were taken. Questionnaires were administered to obtain information about socio-economic status and risk factors for lead exposure. Blood lead levels ranged from 2.2 to 22.4 µg/dl, with the mean blood lead level equalling 7.4. Around 74% of the children had blood lead levels ≥5 µg/dl and 16% had blood lead levels ≥10 µg/dl. Socio-economic factors, and lead melting practices were strongly associated with elevated blood lead levels. Blood lead levels in these remote subsistence fishing communities were unexpectedly elevated, given the absence of local lead industries or other obvious sources of lead exposure. Lead exposure and poisoning is an important, yet neglected, public health concern in South African subsistence fishing communities, and potentially on the entire African continent. Copyright © 2013 Elsevier Inc. All rights reserved.

Lead exposure at firing ranges-a review.

PubMed

Laidlaw, Mark A S; Filippelli, Gabriel; Mielke, Howard; Gulson, Brian; Ball, Andrew S

2017-04-04

Lead (Pb) is a toxic substance with well-known, multiple, long-term, adverse health outcomes. Shooting guns at firing ranges is an occupational necessity for security personnel, police officers, members of the military, and increasingly a recreational activity by the public. In the United States alone, an estimated 16,000-18,000 firing ranges exist. Discharge of Pb dust and gases is a consequence of shooting guns. The objectives of this study are to review the literature on blood lead levels (BLLs) and potential adverse health effects associated with the shooting population. The search terms "blood lead", "lead poisoning", "lead exposure", "marksmen", "firearms", "shooting", "guns", "rifles" and "firing ranges" were used in the search engines Google Scholar, PubMed and Science Direct to identify studies that described BLLs in association with firearm use and health effects associated with shooting activities. Thirty-six articles were reviewed that included BLLs from shooters at firing ranges. In 31 studies BLLs > 10 μg/dL were reported in some shooters, 18 studies reported BLLs > 20 μg/dL, 17 studies > 30 μg/d, and 15 studies BLLs > 40 μg/dL. The literature indicates that BLLs in shooters are associated with Pb aerosol discharge from guns and air Pb at firing ranges, number of bullets discharged, and the caliber of weapon fired. Shooting at firing ranges results in the discharge of Pb dust, elevated BLLs, and exposures that are associated with a variety of adverse health outcomes. Women and children are among recreational shooters at special risk and they do not receive the same health protections as occupational users of firing ranges. Nearly all BLL measurements compiled in the reviewed studies exceed the current reference level of 5 μg/dL recommended by the U.S. Centers for Disease Control and Prevention/National Institute of Occupational Safety and Health (CDC/NIOSH). Thus firing ranges, regardless of type and user classification

Olfactory recognition memory is disrupted in young mice with chronic low-level lead exposure

PubMed Central

Flores-Montoya, Mayra Gisel; Alvarez, Juan Manuel; Sobin, Christina

2015-01-01

Chronic developmental lead exposure yielding very low blood lead burden is an unresolved child public health problem. Few studies have attempted to model neurobehavioral changes in young animals following very low level exposure, and studies are needed to identify tests that are sensitive to the neurobehavioral changes that may occur. Mechanisms of action are not yet known however results have suggested that hippocampus/dentate gyrus may be uniquely vulnerable to early chronic low-level lead exposure. This study examined the sensitivity of a novel odor recognition task to differences in pre-adolescent C57BL/6J mice chronically exposed from birth to PND 28, to 0 ppm (control), 30 ppm (low-dose), or 330 ppm (higher-dose) lead acetate (N = 33). Blood lead levels (BLLs) determined by ICP-MS ranged from 0.02 to 20.31 µg/dL. Generalized linear mixed model analyses with litter as a random effect showed a significant interaction of BLL × sex. As BLLs increased olfactory recognition memory decreased in males. Among females, non-linear effects were observed at lower but not higher levels of lead exposure. The novel odor detection task is sensitive to effects associated with early chronic low-level lead exposure in young C57BL/6J mice. PMID:25936521

Accumulated body burden and endogenous release of lead in employees of a lead smelter.

PubMed Central

Fleming, D E; Boulay, D; Richard, N S; Robin, J P; Gordon, C L; Webber, C E; Chettle, D R

1997-01-01

Bone lead levels for 367 active and 14 retired lead smelter workers were measured in vivo by X-ray fluorescence in May-June 1994. The bone sites of study were the tibia and calcaneus; magnitudes of concentration were used to gauge lead body burden. Whole blood lead readings from the workers generated a cumulative blood lead index (CBLI) that approximated the level of lead exposure over time. Blood lead values for 204 of the 381 workers were gathered from workers returning from a 10-month work interruption that ended in 1991; their blood level values were compared to their tibia and calcaneus lead levels. The resulting relations allowed constraints to be placed on the endogenous release of lead from bone in smelter works. Calcaneus lead levels were found to correlate strongly with those for tibia lead, and in a manner consistent with observations from other lead industry workers. Relations between bone lead concentration and CBLI demonstrated a distinctly nonlinear appearance. When the active population was divided by date of hire, a significant difference in the bone lead-CBLI slope emerged. After a correction to include the component of CBLI existing before the workers' employment at the smelter was made, this difference persisted. This implies that the transfer of lead from blood to bone in the workers has changed over time, possibly as a consequence of varying exposure conditions. Images Figure 1. A Figure 1. B Figure 2. A Figure 2. B Figure 3. A Figure 3. B Figure 4. A Figure 4. B Figure 5. Figure 6. A Figure 6. B Figure 7. Figure 8. Figure 9. A Figure 9. B PMID:9105798

Impact of robotics and a suspended lead suit on physician radiation exposure during percutaneous coronary intervention.

PubMed

Madder, Ryan D; VanOosterhout, Stacie; Mulder, Abbey; Elmore, Matthew; Campbell, Jessica; Borgman, Andrew; Parker, Jessica; Wohns, David

Reports of left-sided brain malignancies among interventional cardiologists have heightened concerns regarding physician radiation exposure. This study evaluated the impact of a suspended lead suit and robotic system on physician radiation exposure during percutaneous coronary intervention (PCI). Real-time radiation exposure data were prospectively collected from dosimeters worn by operating physicians at the head- and chest-level during consecutive PCI cases. Exposures were compared in three study groups: 1) manual PCI performed with traditional lead apparel; 2) manual PCI performed using suspended lead; and 3) robotic PCI performed in combination with suspended lead. Among 336 cases (86.6% manual, 13.4% robotic) performed over 30weeks, use of suspended lead during manual PCI was associated with significantly less radiation exposure to the chest and head of operating physicians than traditional lead apparel (chest: 0.0 [0.1] μSv vs 0.4 [4.0] μSv, p<0.001; head: 0.5 [1.9] μSv vs 14.9 [51.5] μSv, p<0.001). Chest-level radiation exposure during robotic PCI performed in combination with suspended lead was 0.0 [0.0] μSv, which was significantly less chest exposure than manual PCI performed with traditional lead (p<0.001) or suspended lead (p=0.046). In robotic PCI the median head-level exposure was 0.1 [0.2] μSv, which was 99.3% less than manual PCI performed with traditional lead (p<0.001) and 80.0% less than manual PCI performed with suspended lead (p<0.001). Utilization of suspended lead and robotics were observed to result in significantly less radiation exposure to the chest and head of operating physicians during PCI. Copyright © 2016 Elsevier Inc. All rights reserved.

Lead Exposure in Free-Flying Turkey Vultures Is Associated with Big Game Hunting in California

PubMed Central

Kelly, Terra R.; Johnson, Christine K.

2011-01-01

Predatory and scavenging birds are at risk of lead exposure when they feed on animals injured or killed by lead ammunition. While lead ammunition has been banned from waterfowl hunting in North America for almost two decades, lead ammunition is still widely used for hunting big game and small game animals. In this study, we evaluated the association between big game hunting and blood lead concentration in an avian scavenger species that feeds regularly on large mammals in California. We compared blood lead concentration in turkey vultures within and outside of the deer hunting season, and in areas with varying wild pig hunting intensity. Lead exposure in turkey vultures was significantly higher during the deer hunting season compared to the off-season, and blood lead concentration was positively correlated with increasing wild pig hunting intensity. Our results link lead exposure in turkey vultures to deer and wild pig hunting activity at these study sites, and we provide evidence that spent lead ammunition in carrion poses a significant risk of lead exposure to scavengers. PMID:21494326

Lead exposure in free-flying turkey vultures is associated with big game hunting in California.

PubMed

Kelly, Terra R; Johnson, Christine K

2011-04-06

Predatory and scavenging birds are at risk of lead exposure when they feed on animals injured or killed by lead ammunition. While lead ammunition has been banned from waterfowl hunting in North America for almost two decades, lead ammunition is still widely used for hunting big game and small game animals. In this study, we evaluated the association between big game hunting and blood lead concentration in an avian scavenger species that feeds regularly on large mammals in California. We compared blood lead concentration in turkey vultures within and outside of the deer hunting season, and in areas with varying wild pig hunting intensity. Lead exposure in turkey vultures was significantly higher during the deer hunting season compared to the off-season, and blood lead concentration was positively correlated with increasing wild pig hunting intensity. Our results link lead exposure in turkey vultures to deer and wild pig hunting activity at these study sites, and we provide evidence that spent lead ammunition in carrion poses a significant risk of lead exposure to scavengers.