Heavy metals exposures among Mexican farmworkers in eastern North Carolina

Food groups consumption and urinary metal mixtures in women from Northern Mexico

OBJECTIVE

We aimed to evaluate the association between food groups and mixtures of urinary metal concentrations in a sample of women; as well as identify the most important metals within each mixture.

METHODS

This is a cross-sectional analysis between food groups consumption and mixtures of various metals in urine from 439 women, ≥18 years old, from Northen Mexico. We estimated the dietary intake of 20 food groups through a validated semi-quantitative food frequency questionnaire. Urinary metal concentration of aluminum, antimony, arsenic, barium, cadmium, cesium, chromium, cobalt, copper, lead, manganese, magnesium, molybdenum, nickel, selenium, thallium, tin, vanadium, and zinc, were measured by inductively coupled plasma triple quad. We used weighted quantile sum (WQS) regression with binomial family specification to assess the association of food groups and metal mixtures, as well as to identify the most important ones.

RESULTS

We identified tin, lead, and antimony as the most important metals, in the metal mixtures that were positively associated with the consumption of eggs, non-starchy vegetables, fruits, seafood, corn, oil seeds, chicken, soda, legumes, red and/or processed meats, as well as negatively with the consumption of alliums, corn tortillas and/or vegetable oils.

CONCLUSION

Our findings suggest that food consumption is related to more than one metal in the study sample, and highlights the presence of some of them. Further research is required to identify the possible sources of metals in food, as well as the chronic adverse health effects attributed to their simultaneous presence.

Metal exposure and breast cancer among Northern Mexican women: assessment of genetic susceptibility

This study aims to assess breast cancer (BC) association with metals and whether polymorphisms in CYP1A1, CYP1B1, GSTM1 and GSTT1 act as confounders or as modifiers of those relationships. We performed a secondary analysis of 499 histologically confirmed BC cases and the same number of age-matched population controls. We measured urinary concentrations of 18 metals with mass spectrometry. We determined the genetic variants of interest by allelic discrimination and multiplex PCR. After adjusting for covariates, we found BC negatively associated with arsenic, barium, cobalt, copper, magnesium, molybdenum and vanadium concentrations and positively with those of caesium, manganese, tin and thallium. Most associations remained after stratifying by the genetic variants. We identified that polymorphisms in CYP1B1, CYP1A1 and GSTM1 genes interacted with some metals on BC: interaction p-values CYP1B1 G119T × antimony= 0.036, CYP1B1 G119T × cobalt <0.001, CYP1B1 G119T × tin= 0.032, CYP1A1 A4889G × aluminium= 0.018, CYP1A1 A4889G × arsenic= 0.031, CYP1A1 A4889G × nickel= 0.036, CYP1A1 A4889G × vanadium= 0.031 and GSTM1 deletion × barium= 0.035. Exposure to various individual metals, along with genetic characteristics may contribute to BC development. Further studies are warranted to confirm our results.

Breast cancer and urinary metal mixtures in Mexican women

Humans are environmentally exposed to many metals throughout their lives. Simultaneous exposure to several metals could result in synergistic or antagonistic toxicological effects among them; however, the information on exposure to mixtures of metals and breast cancer (BC) is scarce. The objective of this report was to compare metals considered human carcinogens, individually and as mixtures, in women with and without BC. This is a secondary analysis of a population-based case-control study that was carried out from 2007 to 2011 in Northern Mexico. A total of 499 histologically confirmed BC cases and 499 controls were included. Information about sociodemographic, lifestyle and reproductive characteristics was obtained by in-person interviews. Urinary concentrations of aluminum (Al), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), antimony (Sb), cobalt (Co), molybdenum (Mo), tin (Sn), and vanadium (V) were determined by inductively coupled plasma triple quadrupole. Metal mixtures were identified by principal component analysis with creatinine-corrected metals. Over 90% of subjects had metal measurements above the detection limit except tin (86%) and antimony (78.4%). After adjusting by selected covariables, we observed that the individual urinary concentrations of V, Co, and Mo were lower among cases compared to controls; in contrast to Sn that had higher concentrations. We identified two principal component mixtures with opposite relationships with BC: Cr, Ni, Sb, Al, Pb and Sn (OR = 1.15; CI95% 1.06,1.25) and Mo and Co (OR = 0.56; CI95% 0.49,0.64). This is the first study that identified urinary metal mixtures that differed between women with and without BC. Our results warrant confirmation in further prospective epidemiological studies. In addition, the elucidation of underlying mechanisms of metal interactions on BC risk deserves further research.

An Investigation for Heavy Metals’ Contamination in Farmers’ Fingernails: Case Study in Libya

This study aims to assess the concentration levels of heavy metals, which are associated with health hazards: arsenic (As), cadmium (Cd), and lead (Pb) among Libyan farmers using fingernails as a biomarker. Factors that may contribute for accumulation of these toxic heavy metals in the farmers’ fingernails were also evaluated. This cross-sectional study involved 127 farmers and 25 high school teachers living in the same geographical area as the farmers (served as the control group). Fingernail samples of the participants were collected, treated, and analyzed by inductively coupled plasma mass spectrometry (ICP-MS) for As, Cd, and Pb contents after microwave acid digestion. Results of this study indicated that the concentration levels of the investigated heavy metals in fingernail samples of both participating farmers and control group were in order of Pb > Cd > As. Also, the results showed that As, Cd, and Pb levels in the farmers’ fingernails were found to be higher than in the control group by about 9-, 5-, and 2-fold, respectively. This difference for all heavy metals analyzed was found to be statistically significant $\left(P<0.05\right)$ . As a conclusion, the results of this study clearly indicated that Libyan farmers have been exposed to high levels of toxic heavy metals as a result of their agricultural activities compared with the general population living in the same geographical area as farmers, which, in turn, pose a high risk to their health. Thus, toxicological, epidemiological, and clinical studies for the Libyan farmers are strongly recommended.

Case-control study in ALS using the National ALS Registry: lead and agricultural chemicals are potential risk factors

Objective: To identify occupational risk factors for ALS using well-characterized participants with ALS (P-ALS), sibling controls (S-controls), and matched population controls (P-controls) within the National ALS Registry. We also compared oxidative stress (OS) biomarkers between groups. Methods: P-ALS were recruited over 4 years. Demographic, socioeconomic, and medical data were ascertained from medical records and structured interviews. P-ALS were followed prospectively for 2 years or until death, whichever came sooner. S-controls and age-, sex-, race/ethnicity-, and residential location-matched P-controls were recruited over 3 years. Occupational exposure to lead and agricultural chemicals (ACs) were assigned by an occupational hygienist, blinded to case status. OS biomarkers in urine were measured. Results: P-ALS (mean age 62.8 years; 63% males) resided across the United States. Demographic and socioeconomic variables did not differ among P-ALS, S-controls, and P-controls. P-ALS were more likely to report occupations with exposure to lead (adjusted OR (aOR)=2.3, 95% CI 1.1, 4.6) and ACs (aOR = 2.4, 95% CI 1.2, 4.6) compared to pooled controls. Among those with occupations with exposure to both lead and ACs, aOR was 7.2 (95% CI 2.0, 26.1). Urinary 8-oxo-dG was significantly elevated among P-ALS (11.07 ± 5.42 ng/mL) compared to S-controls, P-controls, or pooled controls (pooled 7.43 ± 5.42 ng/mL; p < 0.0001) but was not associated with occupational exposure to either lead or ACs. Conclusions: Findings reveal increased risk of ALS diagnosis among those with occupational exposure to lead and ACs and increased OS biomarkers among cases compared to controls. OS may be an important pathogenic mechanism in ALS.

Association of exposure to multiple metals with papillary thyroid cancer risk in China

Papillary thyroid cancer (PTC) has inflicted huge threats to the health of mankind. Metal pollution could be a potential risk factor of PTC occurrence, but existing relevant epidemiological researches are limited. The current case-control study was designed to evaluate the relationships between exposure to multiple metals and the risk of PTC. A total of 262 histologically confirmed PTC cases were recruited. Age- and gender-matched controls were enrolled at the same time. Urine samples were used as biomarkers to reflect the levels of environmental exposure to 13 metals. Conditional logistic regression models were adopted to assess the potential association. Single-metal and multi-metal models were separately conducted to evaluate the impacts of single and co-exposure to 13 metals. The increased concentration of urinary Cd, Cu, Fe, and Pb quartiles was found significant correlated with PTC risk. We also found the decreased trends of urinary Se, Zn, and Mn quartiles with the ORs for PTC. These dose-response associations between Pb and PTC were observed in the single-metal model and remained significant in the multi-metal model (OR_25-50th=1.39, OR_50-75th=3.32, OR_>75th=7.62, p for trend <0.001). Our study suggested that PTC was positively associated with urinary levels of Cd, Cu, Fe, Pb, and inversely associated with Se, Zn, and Mn. Targeted public health policies should be made to improve the environment and the recognition of potential risk factors. These findings need additional studies to confirm in other population.

Association of urinary metal profiles with serum uric acid: a cross-sectional study of traffic policemen in Wuhan, China

OBJECTIVES

Serum uric acid (SUA) is both a strong antioxidant and one of the key risk factors of cardiovascular diseases (CVDs). We aimed to investigate the associations of urinary metal profile with SUA in traffic policemen in Wuhan, China.

DESIGN

A cross-sectional study was carried out in traffic policemen.

SETTING

A seriously polluted Chinese city.

PARTICIPANTS

A total of 186 traffic policemen were recruited in this study. About 56 of them worked in the logistics department and the other 130 maintained traffic order or dealt with traffic accidents on the roads. All these subjects had worked as a policeman for at least 1 year.

MAIN OUTCOME MEASURES

SUA.

RESULTS

The significantly negative association of lead with SUA was consistent between single-metal and multiple-metal models (p=0.004 and p=0.020, respectively). Vanadium, chromium and tin were reversely associated with SUA levels in the single-metal models after false discovery rate (FDR) adjustment (all P_{_FDR} < 0.05). One IQR increase in vanadium, chromium, tin and lead was associated with 26.9 µmol/L (95% CI -44.6 to -9.2; p=0.003), 27.4 µmol/L (95% CI -46.1 to -8.8; p=0.004), 11.2 µmol/L (95% CI -18.9 to -3.4; p=0.005) and 16.4 µmol/L (95% CI -27.6 to -5.2; p=0.004) decrease in SUA, respectively. Significant interaction between smoking and vanadium on decreased SUV was found (p_{for interaction} = 0.007 and p_{_FDR} = 0.028).

CONCLUSIONS

Urinary vanadium, chromium, tin and lead were negatively associated with SUA. Vanadium and cigarette smoking jointly affected SUA levels. Further studies are needed to replicate these findings and to investigate the potential mechanisms.

Phthalate metabolite exposures among immigrants living in the United States: findings from NHANES, 1999-2014

Phthalates exposure has been linked to multiple health risks, and US immigrants may have different exposures to phthalates due to lifestyle differences. Urinary concentrations of eight phthalate metabolites (mono-ethyl phthalate [MEP], mono-n-butyl phthalate [MnBP], mono-isobutyl phthalate [MiBP], mono-(3-carboxypropyl) phthalate [MCPP], mono-benzyl phthalate [MBzP], mono-2-ethylhexyl phthalate [MEHP], mono-(2-ethyl-5-hydroxyhexyl) phthalate [MEHHP], mono-(2-ethyl-5-oxohexyl) phthalate [MEOHP]) were measured in 10318 US-born and 3511 foreign-born individuals from NHANES 1999-2014. Using multivariate adjusted linear regression, we assessed whether phthalate metabolite levels differed by nativity in the whole population, within racial/ethnic groups, and by years in the US. We also tested whether immigrant demographics predicted phthalate metabolite levels. In fully adjusted models, MEP, MnBP, and MiBP were significantly higher, and MBzP significantly lower, among immigrants than US-born participants. Among immigrants, MnBP and MiBP significantly declined with longer time in the US (P_trend = 0.029 and P_trend = 0.039, respectively), while MCPP and MBzP significantly rose (P_trend = 0.019 and P_trend = 0.043, respectively). Results within each racial/ethnic group were consistent with the whole population. Among immigrants, women had significantly higher metabolite levels than men (all p < 0.01), and MEP, MnBP, and MCPP differed by race/ethnicity. Due to higher phthalate exposures, immigrants may be especially vulnerable to phthalate-associated health problems.

Industrial metal pollution in water and probabilistic assessment of human health risk

Concentration of eight heavy metals in surface and groundwater around Dhaka Export Processing Zone (DEPZ) industrial area were investigated, and the health risk posed to local children and adult residents via ingestion and dermal contact was evaluated using deterministic and probabilistic approaches. Metal concentrations (except Cu, Mn, Ni, and Zn) in Bangshi River water were above the drinking water quality guidelines, while in groundwater were less than the recommended limits. Concentration of metals in surface water decreased as a function of distance. Estimations of non-carcinogenic health risk for surface water revealed that mean hazard index (HI) values of As, Cr, Cu, and Pb for combined pathways (i.e., ingestion and dermal contact) were >1.0 for both age groups. The estimated risk mainly came from the ingestion pathway. However, the HI values for all the examined metals in groundwater were <1.0, indicating no possible human health hazard. Deterministically estimated total cancer risk (TCR) via Bangshi River water exceeded the acceptable limit of 1 × 10^-4 for adult and children. Although, probabilistically estimated 95th percentile values of TCR exceeded the benchmark, mean TCR values were less than 1 × 10^-4. Simulated results showed that 20.13% and 5.43% values of TCR for surface water were >1 × 10^-4 for adult and children, respectively. Deterministic and probabilistic estimations of cancer risk through exposure to groundwater were well below the safety limit. Overall, the population exposed to Bangshi River water remained at carcinogenic and non-carcinogenic health threat and the risk was higher for adults. Sensitivity analysis identified exposure duration (ED) and ingestion rate (IR) of water as the most relevant variables affecting the probabilistic risk estimation model outcome.

Urinary heavy metals in Hispanics 40-85 years old in Doña Ana County, New Mexico

Exposure to As, Cd, Pb, and U among older Hispanic adults residing in underserved communities in southern New Mexico was investigated. Personal information was obtained by standardized interview from 188 adults aged 40-85 years. Urinary metal concentrations were measured and compared to results from the National Health and Nutritional Examination Survey (NHANES). Urinary As and U in study participants significantly (p < .05) exceeded NHANES reference values. Elevated urinary As concentration was significantly associated with older age, Latin American birthplace, clinic site, private-well drinking water, higher self-rated health, and diabetes. Higher urinary Cd was significantly associated with older age, clinic site, female sex, agricultural work, and current cigarette smoking. No personal characteristics were significantly associated with urinary Pb or U. Our results suggest elevated levels of As and U in this population.

A quantitative risk assessment for metals in surface water following the application of biosolids to grassland

During episodic rainfall events, land application of treated municipal sludge ('biosolids') may give rise to surface runoff of metals, which may be potentially harmful to human health if not fully treated in a water treatment plant (WTP). This study used surface runoff water quality data generated from a field-scale study in which three types of biosolids (anaerobically digested (AD), lime stabilised (LS), and thermally dried (TD)) were spread on micro-plots of land and subjected to three rainfall events at time intervals of 24, 48 and 360h following application. Making the assumption that this water directly entered abstraction waters for a WTP without any grassed buffer zone being present, accounting for stream dilution, and modelling various performance scenarios within the WTP, the aim of this research was to conduct a human health risk assessment of metals (Cu, Ni, Pb, Zn, Cd and Cr), which may still be present in drinking water after the WTP. Different dose-response relationships were characterised for the different metals with reference to the lifetime average daily dose (LADD) and the Hazard Quotient (HQ). The results for the LADD show that child exposure concentrations were highest for Cu when the measured surface runoff concentrations from the LS biosolids treatment were used as input into the model. The results for the HQ showed that of all the scenarios considered, Cu had the highest HQ for children. However, values were below the threshold value of risk (HQ<0.01 - no existing risk). Under the conditions monitored, metal concentrations in the biosolids applied to grassland were not considered to result in a risk to human health in surface water systems.

Ergonomics and Beyond: Understanding How Chemical and Heat Exposures and Physical Exertions at Work Affect Functional Ability, Injury, and Long-Term Health

OBJECTIVE

To honor Tom Waters's work on emerging occupational health issues, we review the literature on physical along with chemical exposures and their impact on functional outcomes.

BACKGROUND

Many occupations present the opportunity for exposure to multiple hazardous exposures, including both physical and chemical factors. However, little is known about how these different factors affect functional ability and injury. The goal of this review is to examine the relationships between these exposures, impairment of the neuromuscular and musculoskeletal systems, functional outcomes, and health problems with a focus on acute injury.

METHOD

Literature was identified using online databases, including PubMed, Ovid Medline, and Google Scholar. References from included articles were searched for additional relevant articles.

RESULTS

This review documented the limited existing literature that discussed cognitive impairment and functional disorders via neurotoxicity for physical exposures (heat and repetitive loading) and chemical exposures (pesticides, volatile organic compounds [VOCs], and heavy metals).

CONCLUSION

This review supports that workers are exposed to physical and chemical exposures that are associated with negative health effects, including functional impairment and injury. Innovation in exposure assessment with respect to quantifying the joint exposure to these different exposures is especially needed for developing risk assessment models and, ultimately, preventive measures.

APPLICATION

Along with physical exposures, chemical exposures need to be considered, alone and in combination, in assessing functional ability and occupationally related injuries.

Systematic review of differential inorganic arsenic exposure in minority, low-income, and indigenous populations in the United States

Inorganic arsenic (iAs) is a human carcinogen and associated with cardiovascular, respiratory, and skin diseases. Natural and anthropogenic sources contribute to low concentrations of iAs in water, food, soil, and air. Differential exposure to environmental hazards in minority, indigenous, and low income populations is considered an environmental justice (EJ) concern, yet it is unclear if higher iAs exposure occurs in these populations. A systematic review was conducted to evaluate evidence for differential iAs exposure in the United States (US). The peer-reviewed literature was searched for studies that (1) estimated iAs exposure based on environmental concentrations of iAs in water, food, soil, or iAs biomarkers and (2) examined iAs exposure in minority, indigenous, and low income US populations. Five studies were identified that estimated exposures and provided demographic information about EJ populations. These studies reported arsenic concentrations in water, soil, or food to estimate exposure, with varied evidence of differential exposure. Additionally, six studies were identified that suggested potential arsenic exposure from environmental sources including soil, rice, private well-water, and fish, but did not report data stratified by demographic information. Evidence across these 11 studies was qualitatively integrated to draw conclusions about differential iAs exposure. The total body of evidence is limited by lack of individual exposure measures, lack of iAs concentration data, and insufficient comparative demographic data. Based upon these data gaps, there is inadequate evidence to conclude whether differential exposure to iAs is an EJ concern in the US.

Antioxidant enzymes status and reproductive health of adult male workers exposed to brick kiln pollutants in Pakistan

The present study was designed to study the effect of brick kilns emissions on the reproductive health and biochemical status of brick kiln workers and people living in the area near brick kilns. Body mass index (BMI) was significantly reduced in brick makers, carriers, and bakers compared to the control. Red blood cells count and hematocrit (%) were significantly high in brick bakers while MCH was significantly reduced in brick makers and brick bakers. Heavy metals (lead, cadmium, and chromium) concentration in whole blood of the brick kiln workers were significantly higher as compared to the control. Antioxidant enzymes (CAT, SOD, POD, GSH, and GR) were significantly reduced in brick kiln workers as compared to the control while TBARS level were significantly high in brick bakers as compared to the control. Plasma leutinizing hormone (LH) was significantly high in brick bakers while testosterone concentrations were significantly reduced in brick makers, carriers, and bakers. The present study shows that brick kiln workers and people living in the brick kiln vicinity are exposed to heavy metals and other pollutants that is a serious threat to their health. Alternate technology is needed to be developed and brick kilns should be replaced.

Urinary Cotinine Levels Among Latino Tobacco Farmworkers in North Carolina Compared to Latinos Not Employed in Agriculture

INTRODUCTION

This analysis describes urinary cotinine levels of North Carolina Latino farmworkers, compares cotinine levels of farmworkers to those of Latinos non-farmworkers, determines factors associated with farmworker cotinine levels, and determines if differences in farmworker and non-farmworker cotinine levels are associated with smoking.

METHODS

Data are from 63 farmworkers and 44 non-farmworkers who participated in a larger study of occupational exposures. Questionnaire data and urine samples collected in 2012 and 2013 are analyzed.

RESULTS

Farmworkers had urinary cotinine levels that were far greater than the non-farmworker group. Geometric mean (GM) urinary cotinine levels for farmworkers were 1808.22ng/ml in 2012, and 396.03ng/ml in 2013; corresponding GM levels for non-farmworkers were 4.68ng/ml and 9.03ng/ml. Farmworker GM cotinine levels were associated with harvesting tobacco (1242.77ng/ml vs. 471.26ng/ml; P = .0048), and working in wet shoes (1356.41ng/ml vs. 596.93ng/ml; P = .0148). Smoking did not account for cotinine level differences; the GM cotinine level for farmworkers who did not smoke was 541.31ng/ml; it was 199.40ng/ml for non-farmworkers who did smoke.

CONCLUSION

North Carolina farmworkers experience large nicotine doses. The long-term health effects of these doses are not known. Although procedures to reduce occupational nicotine exposure are known, no changes in work practices or in policies to protect workers have been implemented. Research on the health effects of occupational nicotine exposure must become a priority. Current knowledge of occupational transdermal nicotine exposure must be used to improve occupational safety practice and policy for tobacco workers.

IMPLICATIONS

This study documents the heavy burden of nicotine exposure and dose experienced by tobacco workers in North Carolina. Hundreds of thousands of farmworkers and farmers in the United States and Canada, as well as agricultural workers around the world, share this burden of nicotine exposure and dose. These results support the need to change work practices and regulations to protect workers. They also document the need to delineate the health effects of long-term exposure to high transdermal nicotine doses.

Urinary cadmium and estimated dietary cadmium in the Women's Health Initiative

Cadmium, a heavy metal dispersed in the environment as a result of industrial and agricultural applications, has been implicated in several human diseases including renal disease, cancers, and compromised bone health. In the general population, the predominant sources of cadmium exposure are tobacco and diet. Urinary cadmium (uCd) reflects long-term exposure and has been frequently used to assess cadmium exposure in epidemiological studies; estimated dietary intake of cadmium (dCd) has also been used in several studies. The validity of dCd in comparison with uCd is unclear. This study aimed to compare dCd, estimated from food frequency questionnaires, to uCd measured in spot urine samples from 1,002 participants of the Women's Health Initiative. Using linear regression, we found that dCd was not statistically significantly associated with uCd (β=0.006, P-value=0.14). When stratified by smoking status, dCd was not significantly associated with uCd both in never smokers (β=0.006, P-value=0.09) and in ever smokers (β=0.003, P-value=0.67). Our results suggest that because of the lack of association between estimated dCd and measured uCd, dietary estimation of cadmium exposure should be used with caution in epidemiologic studies.

Essential Metals Zinc, Selenium, and Strontium Protect against Chromosome Damage Caused by Polycyclic Aromatic Hydrocarbons Exposure

Essential metals play important roles in maintaining cellular homeostasis, but the effects of their interaction with the environmental pollutants are still not very well-known in human subjects. The aim of this study was to evaluate the roles of essential metals and their interactions with polycyclic aromatic hydrocarbons (PAHs) on chromosome damage, an early carcinogenic event. A total of 1245 male workers were included in this study and the levels of 11 urinary essential metals, 12 urinary PAH metabolites, plasma concentrations of benzo[a]pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts, and lymphocyte micronucleus (MN) frequencies were monitored. We found that zinc (Zn), selenium (Se), and strontium (Sr) have significant inverse dose-response relationships with MN frequencies (all P < 0.05). Furthermore, the protective roles of Zn, Se, and Sr were mainly shown among subjects with high levels of BPDE-Alb adducts. Significant effect modification of BPDE-Alb adducts on the associations of Zn, Se, and Sr with MN frequencies was observed (all Pinteraction < 0.05). Our study showed evidence that Zn, Se, and Sr play protective roles in reducing chromosome damage, and these effects can be modified by PAH exposure levels. These findings add potential evidence for the preventive effects of Zn, Se, and Sr against carcinogenesis in human subjects.

Urinary metals and heart rate variability: a cross-sectional study of urban adults in Wuhan, China

BACKGROUND

Epidemiological studies have suggested an association between external estimates of exposure to metals in air particles and altered heart rate variability (HRV). However, studies on the association between internal assessments of metals exposure and HRV are limited.

OBJECTIVES

The purpose of this study was to examine the potential association between urinary metals and HRV among residents of an urban community in Wuhan, China.

METHODS

We performed a cross-sectional analysis of 23 urinary metals and 5-min HRV indices (SDNN, standard deviation of normal-to-normal intervals; r-MSSD, root mean square of successive differences in adjacent normal-to-normal intervals; LF, low frequency; HF, high frequency; TP, total power) using baseline data on 2,004 adult residents of Wuhan.

RESULTS

After adjusting for other metals, creatinine, and other covariates, natural log-transformed urine titanium concentration was positively associated with all HRV indices (all p < 0.05). Moreover, we estimated negative associations between cadmium and r-MSSD, LF, HF, and TP; between lead and r-MSSD, HF, and TP; and between iron, copper, and arsenic and HF, SDNN, and LF, respectively, based on models adjusted for other metals, creatinine, and covariates (all p < 0.10). Several associations differed according to cardiovascular disease risk factors. For example, negative associations between cadmium and r-MSSD were stronger among participants ≤ 52 years of age (vs. > 52), current smokers (vs. nonsmokers), body mass index < 25 kg/m2 (vs. ≥ 25), and among those who were not hypertensive.

CONCLUSIONS

Urine concentrations of several metals were associated with HRV parameters in our cross-sectional study population. These findings need replication in other studies with adequate sample sizes.

Urinary concentrations of toxic and essential trace elements among rural residents in Hainan Island, China

BACKGROUND

Toxic element exposure and essential trace element consumption may have changed after the Chinese economy transformed to a market-oriented system. The objectives of this study were to measure urinary concentrations of toxic (arsenic, cadmium, lead) and essential trace (selenium, zinc, copper) elements among rural residents in Hainan, China and to examine if variations in economic development are linked to differences in toxic and trace element exposure.

METHODS

We conducted a questionnaire-based survey and undertook anthropometric measurements of residents aged ≥20 years (n = 599). Urinary samples were collected and analyzed using inductively coupled plasma mass spectrometry.

RESULTS

The median (μg/g creatinine) element concentrations were: arsenic, 73.2; cadmium, 1.8; lead, 3.1; selenium, 36.5; zinc, 371; and copper, 11.0. Intra-community variation in element concentrations was explained by age (arsenic, cadmium, zinc and copper), sex (arsenic, cadmium and selenium: higher in females; zinc: higher in males), body mass index (cadmium) and individual involvement in the market economy as indexed by agrochemical use (lead and selenium). The degree of community-level economic development, which was determined by the proportion of people living in better housing among the study communities, was positively associated with cadmium concentration.

CONCLUSIONS

The degree of community-level economic development was positively associated with urinary cadmium concentration while individual involvement in the market economy was positively associated with lead and selenium.

Lifetime and current pesticide exposure among Latino farmworkers in comparison to other Latino immigrants

BACKGROUND

Pesticide exposure poses a health risk for farmworkers. This analysis documents lifetime and current pesticide exposure of North Carolina Latino migrant farmworkers, with comparison to non-farmworker Latino immigrants.

METHODS

During May to October 2012, 235 Latino farmworkers and 212 Latino non-farmworkers completed interviews with items to construct measures of lifetime, current residential and occupational pesticide exposure.

RESULTS

Farmworkers experience levels of lifetime and residential pesticide exposure that are consistently greater than among non-farmworkers. Farmworkers report a large number of occupational pesticide exposures. Lifetime exposure and current residential pesticide exposure are related to social determinants. Education is inversely related to lifetime pesticide exposure for farmworkers and non-farmworkers; farmworkers with H-2A visas report greater residential pesticide exposure than those without H-2A visas.

CONCLUSIONS

Occupational safety policy needs to consider these patterns of lifetime exposure when setting standards. Health care providers should be aware of the lifetime and current exposure of this vulnerable population.

Medical repatriation of migrant farm workers in Ontario: a descriptive analysis

BACKGROUND

Approximately 40 000 migrant farm workers are employed annually in Canada through temporary foreign worker programs. Workers experiencing health conditions that prevent ongoing work are normally repatriated to their home country, which raises concerns about human rights and health equity. In this study, we present data on the reasons for medical repatriation of migrant farm workers in Ontario.

METHODS

In this retrospective descriptive study, we examined medical repatriation data from Foreign Agricultural Resource Management Services, a non-profit corporation managing the contracts of more than 15 000 migrant farm workers in Ontario annually. We extracted repatriation and demographic data for workers from 2001-2011. Physician volunteers used a validated system to code the reported reasons for medical repatriation. We conducted descriptive analyses of the dominant reasons for repatriation and rates of repatriation.

RESULTS

During 2001-2011, 787 repatriations occurred among 170 315 migrant farm workers arriving in Ontario (4.62 repatriations per 1000 workers). More than two-thirds of repatriated workers were aged 30-49 years. Migrant farm workers were most frequently repatriated for medical or surgical reasons (41.3%) and external injuries including poisoning (25.5%).

INTERPRETATION

This study provides quantitative health data related to a unique and vulnerable occupational group. Our findings reinforce existing knowledge regarding occupational hazards and health conditions among migrant farm workers. Medical repatriation of migrant farm workers merits further examination as a global health equity concern.

Biomonitoring of cadmium, chromium, nickel and arsenic in general population living near mining and active industrial areas in Southern Tunisia

The human health impact of the historic and current mining and industrial activities in Tunisia is not known. This study assessed the exposure to metals in the population of Southern Tunisia, using biomonitoring. The aim of this pilot study was to evaluate metal exposure on 350 participants living near mining and active industrial areas in the South of Tunisia. Blood specimens were analyzed for metals (Cd, Cr, As, and Ni) by Atomic Absorption Spectrometer equipped with Zeeman background correction and AS-800 auto sampler by graphite furnace and graphite tubes with integrated L'vov platform. The sample population was classified according to different age groups, sex, smoking habit, sea food and water drinking consumption, occupational exposure, amalgam fillings and place of residence. The blood As, Cd, Cr and Ni values expressed as mean ± SD were 1.56 ± 2.49, 0.74 ± 1.15, 35.04 ± 26.02 and 30.56 ± 29.96 μg/l, respectively. Blood Cd and Ni levels in smokers were 2 and 1.2 times, respectively, higher than in non-smokers. Blood Cd levels increase significantly with age (p = 0.002). As, Cd and Ni were significantly correlated with gender and age (p < 0.05). Cd level in blood samples of subjects occupationally exposed was 1.3 times higher than that of non-exposed. Blood metals were not significantly affected by amalgam fillings, place of living and sea food and drinking water consumption. This first biomonitoring study of metal exposure in the South of Tunisia reveals a substantial exposure to several metals. The pathways of exposure and health significance of these findings need to be further investigated.

Immigration, Work, and Health: A Literature Review of Immigration Between Mexico and the United States

Understanding the influence someone's job or career has on their health goes beyond the physical, emotional and social hazards, risks and conditions that they face at work. One's job or career also exerts a significant influence over other aspects of life that contribute or detract from their health and that of their family. Work is the major incentive for Latin American migration to the United States. Latino immigrants experience increasingly poorer outcomes for physical health and chronic diseases the longer they remain in the U.S. The strong link between work and immigration suggests that, for many Latin Americans, immigration can be understood as a career path which puts them, and their family members, in situations that can change their physical, emotional, and social health as a condition of their employment. Given the large number of Latin Americans who emigrate for work, it is essential that the unique physical, mental and social impacts of emigration are accounted for when working with clients impacted by emigration at the individual, family and community level as well as those social workers practicing at the system level. This paper is a literature review that explores the impact that emigrating for work has on the health of those that emigrate and their family members that stay behind.

Differences in prenatal exposure to mercury in South African communities residing along the Indian Ocean

Mercury is a persistent environmental pollutant that has the potential to adversely affect human health, particularly, foetal neurodevelopment. The purpose of the study was to investigate prenatal mercury (Hg) exposure in the population in three sites along the South Africa coast. Study subjects included women (n=350) who were admitted for delivery at the local hospitals. Maternal and cord blood samples were collected to measure total mercury and each participant was required to answer a questionnaire. The 90th percentile of mercury levels in maternal and cord blood of the total population was 1.15 μg/l and 1.67 μg/l, respectively. Site 1 (Manguzi) participants had the highest maternal geometric mean (GM) values of 0.93 μg/l, which was significantly different from Site 2 (Port Shepstone) (0.49 μg/l) and Site 3 (Empangeni) (0.56 μg/l) (ANOVA test, p<0.001). Umbilical cord blood GM Hg level for Site 1 (1.45 μg/l) was more than double the GM Hg level in Site 2 (0.70 μg/l) and Site 3 (0.73 μg/l). Univariate analysis indicated that the following maternal characteristics were positive predictors for elevated umbilical cord Hg levels: maternal blood Hg levels, living with a partner, residing in Site 1, living in informal housing, using wood and gas for cooking, borehole water as a drinking source, and a member of the household being involved in fishing. Maternal dietary predictors of elevated Hg levels in umbilical cord blood included consuming fresh fish, tinned fish, fruit or dairy products, daily. This study provides baseline data and reveals that 2% of the study population were above the EPA's reference value (5.8 μg/l) suggesting low level exposure to mercury in pregnant women and the developing foetus in South Africa. Further research is required to explore the sources of elevated Hg levels in Site 1.

Effect of long-term human exposure to environmental heavy metals on the expression of detoxification and DNA repair genes

The present study was designed to evaluate the influence of long-term environmental human exposure to three heavy metals, lead (Pb), cadmium (Cd), and mercury (Hg), on the expression of detoxifying, xenobiotic metabolizing, and DNA repair genes in Mahd Ad-Dahab city. The study groups consisted of 40 healthy male residents (heavy metal-exposed) and 20 healthy male from Riyadh city, 700 km away, and served as control group. The heavy metal-exposed group with high exposure to Pb, Cd, or Hg was divided into three subgroups Pb-, Cd-, and Hg-exposed groups, respectively. The mRNA expression levels of detoxifying, NQO1, HO-1, GSTA1, MT-1, and HSP70, were significantly decreased in all heavy metal-exposed group as compared to control group. This was accompanied with a proportional decrease in the expression of xenobiotic metabolizing gene, cytochrome P4501A1. On the other hand, the DNA repair gene OGG1 and the 8-OHdG level were dramatically inhibited in Cd-exposed group only.

Occupational health outcomes for workers in the agriculture, forestry and fishing sector: implications for immigrant workers in the southeastern US

BACKGROUND

Workers in the Agriculture, Forestry, and Fisheries (AgFF) sector experience exposures directly related to the work itself, as well as the physical environment in which the work occurs. Health outcomes vary from immediate to delayed, and from acute to chronic.

METHODS

We reviewed existing literature on the health outcomes of work in the AgFF sector and identified areas where further research is needed to understand the impact of these exposures on immigrant Latino workers in the southeastern US.

RESULTS

Outcomes related to specific body systems (e.g., musculoskeletal, respiratory) as well as particular exposure sources (e.g., pesticides, noise) were reviewed. The most extensive evidence exists for agriculture, with a particular focus on chemical exposures. Little research in the southeastern US has examined health outcomes of exposures of immigrant workers in forestry or fisheries.

CONCLUSION

As the AgFF labor force includes a growing number of Latino immigrants, more research is needed to characterize a broad range of exposures and health outcomes experienced by this population, particularly in forestry and fisheries.

Environmental and Occupational Health Risks Among Agricultural Workers Living in a Rural Community Near Petroleum Refinery and Motorway in Skopje Region

To assess health risks in agricultural workers associated with environmental exposure to pollutants released from a petroleum refinery and from traffic, we performed a cross-sectional study that included 119 randomly selected subjects divided in two groups. Group 1 included 60 agricultural workers living in a rural community near the petroleum refinery and a motorway overpass, whereas Group 2 consisted of 59 agricultural workers performing similar activities and living in a rural community with no exposure to industrial and traffic pollutants. Risk assessment included a questionnaire, blood pressure measurement, spirometry, laboratory tests, and toxicological analysis. The groups showed a similar prevalence of health problems, with exception of muscle pain in the extremities, headache, and fatigue, which were significantly more common in Group 1. Diastolic blood pressure was higher in Group 1, but not significantly (p=0.057). The same is true for blood carbon monoxide. Significantly higher in Group 1 were blood haemoglobin (p=0.001) and blood lead (p<0.001). Serum cholinesterase activity was similar in both groups. Our findings indicate the need of regular medical exams, ambient monitoring and environmental impact assessment in agricultural population in order to detect individuals at risk and to institute adequate preventive measures.