Exposure assessment of polybrominated diphenyl ethers (PBDEs) in Mexican children

Release, transformation, and risk factors of polybrominated diphenyl ethers from landfills to the surrounding environments: A review

Polybrominated diphenyl ethers (PBDEs) serve as brominated flame retardants when added to various products. When these products reach their end of life, a large amount of domestic waste containing PBDEs enters the landfills. Given their weak chemical bonds, they are easily affected by physical, chemical, and biological processes. These processes result in their release and the subsequent contamination of the surrounding soil, groundwater, and atmosphere, causing harm to humans and ecosystems. However, despite the progress made in the research of PBDEs over the years, understanding of the environmental behavior and fate of pollutants is still limited. With the development of cities, the release of PBDEs in old landfills will gradually increase the risk to the surrounding environment. Here we review the biological and nonbiological transformation of PBDEs and their derivatives in landfills and surrounding areas, as well as their distribution in soil, groundwater, and atmosphere. Specifically, this review aims to provide insights into the following aspects: 1) the biological (plant, animal, and microbial) and nonbiological (metal catalysis and photodegradation) conversion of PBDEs and their derivatives in landfills and surrounding areas; 2) the distribution of landfill-sourced PBDEs in the soil, groundwater, atmosphere and cross-media migration; and 3) suggestions and future research directions for the management and control of PBDEs in landfills.

Global distribution and trends of polybrominated diphenyl ethers in human blood and breast milk: A quantitative meta-analysis of studies published in the period 2000-2019

Polybrominated diphenyl ethers (PBDEs) are a class of flame-retardants that are found throughout the human body. However, global trends and diversity of the concentrations in human body and the potential risks remain largely unresolved. Based on published data during 2000-2019, we conducted a systematic meta-analysis to understand the burden and risks of PBDEs in humans and their spatiotemporal variations. The report provides a global picture of PBDE concentrations in human blood and breast milk. We found the levels of body PBDE burden in the North American population were higher than those from Asia and Europe. However, high concentrations of blood PBDEs in occupational population from Asia were observed, largely because of poorly controlled e-waste recycling operations. Penta- and deca-BDE were the main contributors in North America and Asia, respectively, reflecting the difference in the production and use of these chemicals. On a global scale, no substantial decreases in the concentrations of PBDEs in the blood and breast milk were observed, although most of the chemicals have been phased out. The results suggested that humans will be exposed to PBDEs with relatively high concentrations in a certain period because of the legacy in products and the environmental media. And the potential health risks necessitate careful study in the future. Our results also remind that the uses of degradation-resistant chemicals should be attached great importance to their safety.

DNA damage in earthworms by exposure of Persistent Organic Pollutants in low basin of Coatzacoalcos River, Mexico

Persistent Organic Pollutants (POPs) are stable organic chemicals that represent a potential risk for ecosystems due to their high toxicity, persistence and biomagnification through food chains. Bioindicators in ecosystems have emerged to assess the effect of environmental pollutants. Earthworms are some of the most common bioindicator organisms in terrestrial ecosystems. The main objective of this study was to evaluate the geontoxicity of POP exposure in wild earthworms captured at different levels of urbanization throughout the lower basin of the Coatzacoalcos River (industrial, urban and rural areas). POP soil and earthworm tissue concentrations were measured via Gas-Mass Chromatography, and earthworm DNA damage was evaluated through the comet assay. The greatest concentrations of ΣPOPs, DDT and HCH were found in soil from industrial sites, followed by urban and rural areas (504.68, 383.10, 298.16; 22.6, 4.6, 2.6 and 433.7, 364, 255.6 mg/kg, respectively). Unlike other pollutants, mean ΣPCBs values were highest for industrial soil samples, followed by those from rural and urban areas (41.10, 33.97 and 12.44 mg/kg respectively). For all earthworm tissue POP analyses, the highest concentrations were found in individuals from industrial sites, followed by the urban and rural areas. Furthermore, the highest levels of DNA damage were registered in the industrial area, followed by the urban and rural areas. These assays suggest a strong links among regional soil contamination, POPs bioavailability and the potential risk of detrimental health effects for organisms that inhabit surface soil (soil life). Earthworms contribute vital ecosystem services that could be affected by these results. This work provides evidence of the potential ecological risk that exists in the Lower Basin of the Coatzacoalcos River.

Air pollution and body burden of persistent organic pollutants at an electronic waste recycling area of China

This paper reviews the concentrations of persistent organic pollutants (POPs) in atmosphere of an electronic waste (e-waste) recycling town, Guiyu, in Southeast China, focusing on polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). We assess the evidence for the association between air pollution and human body burden, to provide an indication of the severity of respiratory exposure. Compared with standards and available existing data for other areas, it clearly shows that four typical POPs, derived from recycling processes, lead to serious atmospheric pollution and heavy body burden. From published data, the estimated respiratory exposure doses of Guiyu adults and children, varied between 2.48-10.37 and 3.25-13.6 ng kg^-1 body weight (bw) day^-1 for PBDEs, 2.31-7.6 and 4.09-13.58 pg World Health Organization-Toxic Equivalent Quantity (WHO-TEQ) kg^-1 bw day^-1 for PCDD/Fs, 5.57 and 20.52 ng kg^-1 bw day^-1 for PCBs, and 8.59-50.01 and 31.64-184.14 ng kg^-1 bw day^-1 for PAHs, respectively. These results show that air pollution is more harmful to children. Furthermore, except for PBDEs, the hazard quotient (HQ) of the other three pollutants was rated more than 1 by respiratory exposure only, and all of them are at risk of carcinogenesis. So we speculate these pollutants enter the body mainly through air inhalation, making respiratory exposure may be more important than dietary exposure in the Guiyu e-waste recycling area. Effective management policies and remediation techniques are urgently needed to prevent the deterioration of ambient air quality in the e-waste recycling area.

Human biomonitoring in Australian children: Brominated flame retardants decrease from 2006 to 2015

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD) were used intensively as flame retardants, worldwide. They have been detected in human serum samples and PBDEs have been found to be elevated in young children. Commercial Penta- and Octa-PBDE mixtures were banned in Australia in 2005, while HBCDD was banned worldwide in 2013. We investigated PBDE and HBCDD concentrations in serum collected from young children. We also investigated temporal trends in PBDE concentration 10 years after their Australian ban. Surplus human blood serum samples were collected through a pathology clinic (n = 800), in 2014/15, stratified by age (0-6, 6-12, 12-18, 18-24, 24-30, 30-36, 36-42, 42-48, 48-54 and 54-60 months) and sex and pooled for analysis of PBDEs (BDEs -28, -47, -99, -100, -153, -154, -183) and HBCDD. In 2014/15, the geometric mean concentration of the sum of all PBDEs measured (ΣPBDEs) was 4.5 ng/g lipid (median: 4.6 ng/g lipid, range: 0.88-26 ng/g lipid). A positive association between BDE-47 concentration and age was observed (R = 0.41, p = 0.008), however there were no trends between other PBDE congeners or HBCDD and age. There were no significant differences between genders for PBDEs (t-test, p = 0.802) or HBCDD (t-test, p = 0.740).The highest concentrations observed were in pools from the females 30-36 month (26 ng/g lipid) and Males 6-12 month (21 ng/g lipid) categories. BDEs -47 and -99 were the predominant congeners with a combined average contribution of 75% of ΣPBDEs. PBDEs showed a significant reduction in children aged 0-4 years over an eight year period. In 2014/15, the mean (range) concentration of BDE-47 is 2.8 (0.23 to 11) ng/g lipid compared to pools in 2006/07 at 19 (3-55) ng/g lipid (p < 0.0001) and for BDE-153 is 0.73 (<0.1 = -2.9) ng/g lipid compared to pools in 2006/07 at 4.7 (2-10) ng/g lipid (p < 0.0001). HBCDD concentrations were lower than PBDEs with a mean concentration of 0.45 ng/g lipid. There were no temporal trends observed for HBCDD when compared to samples collected in 2012. The dominant stereoisomer was α-HBCDD (mean = 0.38 ng/g lipid) with an average contribution of 65% towards ΣHBCDD. Levels of PBDEs in young Australian children have significantly decreased since the bans of commercial Penta- and Octa-BDE in 2005. There has been no observed decrease in HBCDD levels in Australian children since its ban in 2012.

Exposure to Mixtures of Pollutants in Mexican Children from Marginalized Urban Areas

Background:

Exposure to contaminant mixtures in developing countries is an important public health issue. Children are identified as the most susceptible group to adverse health effects due to the exposure.

Objective:

The aim of this study was to conduct a screening for mixture pollutants in Mexican children in urban marginalized communities.

Methods:

We analyzed children (aged 6–12 years old) who resided in four urban marginalized communities in San Luis Potosi, Mexico: i) Bellas Lomas (BEL), a site with vehicular traffic; ii) Tercera Chica (TC), a site with brick kilns; Iii) Rincon de San Jose (SJR), a site with a hazardous waste landfill; and (iv) Morales (MOR) a metallurgical zone with copper-arsenic and electrolytic zinc smelters. Polycyclic Aromatic Hydrocarbons (1-hydroxypyrene (1-OHP)), benzene (trans, trans-muconic acid (t,t-MA), manganese, arsenic and fluoride were quantified in urine and lead in blood samples.

Findings:

Our results indicate that median exposures to manganese were 4.4, 5.2, 5.8 and 6.3 µg/L for BEL, TC, SJR and MOR, respectively. For BEL, fluoride was present at a higher concentration with 2.3 mg/L followed by MOR, TC and SJR with 1.7, 1.5 and 1.2 mg/L respectively. The highest concentrations of arsenic that were found were 11 µg/L in MOR and lead concentration was reported between 4.2 and 6.8 µg/dL, in BEL, TC and MOR. 1-OHP and t,t-MA were higher in TC (0.23 µmol/mol creatinine (cr), 429.7 µg/g cr, respectively) followed by SJR (0.09 µmol/mol cr, 427.4 µg/g cr), MOR (0.03 µmol/mol cr, 258.6 µg/g cr) and BEL (0.06 µmol/mol cr, 220.6 µg/g cr).

Conclusion:

Considering the large number of people, especially children, exposed to multiple pollutants, it is important to design effective intervention programs that reduce exposure and the resultant risk in the numerous urban marginalized communities in Mexico.

Polybrominated diphenyl ethers (PBDEs) levels in blood samples from children living in the metropolitan area of Guadalajara, Jalisco, Mexico

The aim of this study was to perform a polybrominated diphenyl ethers (PBDEs) exposure assessment using blood samples collected from children living in the metropolitan area of Guadalajara, Jalisco, Mexico (GDL). Five congeners of PBDEs were analyzed using a gas chromatography/mass spectrometry technique. The blood concentrations of total PBDEs ranged from 5.50 to 169 ng/g lipid (42.0 ± 18.0 ng/g lipid; mean ± standard deviation). Regarding BDE congeners, the main congener (highest blood levels) was BDE99 (14.5 ± 5.50 ng/g lipid), followed by BDE100 (9.80 ± 3.40 ng/g lipid) and BDE154 (9.80 ± 5.90 ng/g lipid), and finally BDE153 (5.80 ± 2.30 ng/g lipid) and BDE47 (2.20 ± 1.20 ng/g lipid). In conclusion, blood PBDEs concentrations of concern were detected in this study, as blood levels were similar to the ones found in North America (the highest worldwide).

Occurrence and profiles of polybrominated diphenyl ethers (PBDEs) in riverine sediments of Shanghai: a combinative study with human serum from the locals

Herein, we studied the occurrence and profiles of thirteen PBDE congeners in 30 river sediment samples from Shanghai, China. The concentrations of Σ₁₃PBDEs ranged from 110 to 13,071 pg g ^-1 dw, with an average value of 2,841 pg g ^-1 dw. BDE-209 was the predominant congener accounting for more than 65 % of total PBDEs, demonstrating that the major source of PBDEs in sediment samples was associated with the prevalent use of technical deca-BDE products. Moreover, low brominated BDEs in sediments also came from the degradation of higher brominated BDEs. In addition, taking into consideration of dietary exposure, PBDEs in serum samples collected from the locals were also detected with range of 419-26,744 pg g^-1 (average 5,561 pg g ^-1), which suggested a relatively low burden of PBDEs contamination to human body compared with the condition in other place. And in serum, low brominated compounds constituted the majority of total PBDE congeners.

Biomonitoring of persistent organic pollutants (POPs) in child populations living near contaminated sites in Mexico

The aim of this study was to conduct a POP biomonitoring programme for children in high-risk areas. We evaluated 247 serum samples from children between the ages of 6 and 12years old from two zones in Mexico: (1) indigenous zones, which included Cuatlamayan (CUA), Tocoy (TOC), and Santa Maria Picula (SAM); and (2) industrial zones, which included Tercera Chica (TC), Industrial San Luis (IND) and Rincon de San Jose (SJR); Mundo Nuevo (MN); and Alpuyeca (ALP). Our results showed that α-endosulfan was similar to CUA, TOC, SAM, TC and MN (178.6-306.9ng/g lipid). β-Endosulfan levels were higher in ALP (901.5ng/g lipid), followed by CUA (139.9ng/g lipid) and TOC, SAM, TC and MN, which had similar levels (55.4-64.5ng/g lipid). For endosulfan sulfate, the ALP community had the highest concentration levels (1096.4ng/g lipid), whereas CUA and TOC (212.3 and 289ng/g lipid, respectively) had concentrations similar to those found in SAM and TC (99.5 and 119.1ng/g lipid, respectively). DDE levels were found in malaria-endemic areas of SAM, CUA and TOC (1782.2, 1358.3 and 57.0ng/g lipid), followed by MN (35.1ng/g lipid). HCB concentration levels were found to be higher in MN and SJR (691.8 and 575.4ng/g lipid, respectively), followed by CUA and TC (363.9 and 269.1ng/g lipid, respectively), with levels similar to those found in TOC and SAM (191.8 and 181.9ng/g lipid, respectively). Finally, PCB 101 concentration levels were found to be the highest in ALP (1032.7ng/g lipid), followed by similar levels of SJR and IND (567.5 and 327.3ng/g lipid, respectively) and TC and MN, with 109.1 and 144.5ng/g lipid, respectively. The evidence provided by this exploratory study indicates that the evaluation of the health risks posed to children living in contaminated areas is a high priority health issue.

Assessment of exposure to mixture pollutants in Mexican indigenous children

The aim of the present work was to complete an exposure assessment in three Mexican indigenous communities using the community-based health risk assessment, which is the first step in the CHILD framework. We used 1-hydroxypyrene (1-OHP) as an exposure biomarker to polycyclic aromatic hydrocarbons (PAHs) and trans, trans-muconic acid (t,t-MA) as an exposure biomarker to benzene, persistent organic pollutants (POPs), lead, manganese, arsenic, and fluoride. Anthropometric measurements were also taken. In these communities, high percentages of children with chronic malnutrition were found (28 to 49 %) based on their weight and age. All communities showed a high percentage of children with detectable levels of four or more compounds (70 to 82 %). Additionally, our results showed that in indigenous communities, children are exposed to elevated levels of certain environmental pollutants, including manganese with 17.6, 16.8, and 7.3 μg/L from SMP, TOC, and CUA, respectively. Lead and HCB levels were similar in the indigenous communities (2.5, 3.1, and 4.2 μg/dL and 2.5, 3.1, and 3.7 ng/mL, respectively). 1-OHP and t,t-MA levels were higher in TOC (0.8 μmol/mol of creatinine, 476 μg/g of creatinine, respectively) when compared with SMP (0.1 μmol/mol of creatinine, 215.5 μg/g of creatinine, respectively) and CUA (0.1 μmol/mol of creatinine, 185.2 μg/g of creatinine, respectively). DDE levels were 30.7, 26.9, and 9.6 ng/mL in CUA, SMP, and TOC, respectively. The strength of this study is that it assesses exposure to pollutants with indications for the resultant risk before an intervention is made by the CHILD program to manage this risk in the indigenous communities. Considering the large number of people, especially children, exposed to multiple pollutants, it is important to design effective intervention programs that reduce exposure and the resultant risk in the numerous indigenous communities in Mexico.

Exposure Assessment to Environmental Chemicals in Children from Ciudad Juarez, Chihuahua, Mexico

It has been demonstrated that the human biomonitoring of susceptible populations is a valuable method for the identification of critical contaminants. Therefore, the purpose of this study was to assess the exposure profile for arsenic (As), lead (Pb), mercury (Hg), 1-hydroxypyrene (1-OHP), 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT), 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) in children living in Ciudad Juarez, Chihuahua, Mexico (a major manufacturing center in Mexico). In 2012, we evaluated a total of 135 healthy children living in Ciudad Juarez since birth. The total PBDEs levels ranged from nondetectable (< LOD) to 215 ng/g lipid, with a mean total PBDEs level of 29.5 ± 53.0 ng/g lipid (geometric mean ± standard deviation). The mean total PCBs level in the study participants was 29.0 ± 10.5 ng/g lipid (range 4.50-50.0 ng/g lipid). The mean concentration of total DDT (DDT + DDE) was 11.9 ± 6.70 ng/g lipid (range 3.00-26.0 ng/g lipid). The mean 1-OHP levels was 1.2 ± 1.1 µmol/mol creatinine (range <LOD to 3.90 µmol/mol creatinine). Regarding heavy metals levels, the mean urinary As levels was 19.5 ± 3.07 µg/g creatinine, for urinary mercury the levels ranged from <LOD to 11.5 µg/L, with a mean value of 2.10 µg/L, and finally, the mean blood lead level was 4.20 ± 3.80 µg/dL. In conclusion, our data indicate high exposure levels to chemicals analyzed in the children living in the study community. Therefore, a biomonitoring program for the surveillance of the child population in Ciudad Juarez is necessary.

Serum concentrations of PCBs and OCPs among prepubertal Korean children

Although children are more vulnerable than adults to environmental hazards, due to their physiological and behavioral characteristics, few studies have assessed their internal exposure to persistent organic pollutants (POPs). The objective of this study was to determine the serum levels of certain polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) among pre-pubertal children in Korea and examine their variation with age and gender. We analyzed a total of 51 POPs in 214 children (age range, 7-9 years), using data from the Ewha Birth and Growth Cohort Study. To examine change over time, POP concentrations were measured at both 7 and 9 years of age in a sub-cohort of 26 children. The median and interquartile range (IQR, 25th to 75th percentiles) data for the sum of PCB congeners was 26.44 ng/g lipid (18.27-37.63 ng/g lipid). The median (IQR) concentration for the sum of OCPs was 74.82 ng/g lipid (51.11-112.45 ng/g lipid). Our results showed significant increases in serum concentrations of total PCBs with age (p = 0.0001), no gender dependence of total PCBs (p = 0.38) and total OCPs (p = 0.12), and strong correlations between individual POPs. Childhood exposure to POPs was relatively low compared to other studies carried out in different countries. However, even though the use of POPs has been banned since 2001, our results indicated that children in the general population are still exposed to various POPs. Because long-term, low-level exposure to POPs in the general population remains a concern for human health, future research should examine major routes of exposure and identification of risk factors.

Temporal trends in the levels of polychlorinated dioxins, -furans, -biphenyls and polybrominated diethyl ethers in bank voles in Northern Finland

Dioxin-like chemicals and brominated flame retardants are ubiquitous in the environment, despite the introduction of international prohibitions and restrictions. These chemicals do not remain in the vicinity of their source, instead they can be transported over long distances, in fact even to pristine areas in the northern latitudes. However, there have been rather few time series experiments monitoring the trends in the levels of chlorinated and brominated forms of these chemicals in the environment. In this study, the concentrations of polychlorinated dibenzo-p-dioxins and -furans (PCDDs/Fs), polychlorinated biphenyls (PCBs) and polybrominated diethyl ethers (PBDEs) were measured in the liver and muscle of bank voles (Myodes glareolus) caught in a remote area in Finnish Lapland during 1986-2007. Five time points were selected: years 1986, 1992, 1998, 2003 and 2007. The levels of PCDDs/Fs and PCBs declined from 1986 until 2003 in both females and males, but tended to increase again in 2007. The peak levels of the most abundant PBDE congeners (PBDEs 47, 99, 100 and 153) were measured in 1998 and 2003. These results reveal that the levels of dioxin-like chemicals remain high also in rural areas in Lapland, whereas the concentrations of brominated flame retardants decreased and follow the current restriction prohibitions.

Influence of physicochemical and chemical parameters on polybrominated diphenyl ethers in selected landfill leachates, sediments and river sediments from Gauteng, South Africa

Polybrominated diphenyl ethers (PBDEs) are known to be persistent, endocrine disruptors and bioaccumulative and can cause adverse health effects in animals and humans. In this study, river and landfill sediment samples were collected from selected rivers and municipal solid waste landfill (MSWL) sites across Gauteng Province in South Africa to determine the levels of common PBDEs (BDE-17, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183 and BDE-209). The mean and median concentrations of Σ8 PBDEs from river sediment samples was 2.4 and 0.4 ng g(-1), respectively, and a range of 0.8-114 ng g(-1). The highest concentration of Σ8 PBDEs (43.6 ng g(-1)) was observed at Jukskei River with more than two orders of magnitude greater than the rest. The observed total PBDE concentrations in landfill sediment and leachate samples ranged from 0.8 to 8.4 ng g(-1) and 127-3,702 pg L(-1) for the two matrices. BDE-209 was predominantly detected in most of the sediment samples. Two of the MSWLs which are lined with geomembranes gave the highest concentrations of ∑7 PBDEs (2,678 and 3,702 pg L(-1)). Correlation values for ∑7 PBDEs versus Co (r = 0.65), Cu (r = 0.52), Mn (r = 0.10), Mg (r = 0.76), Ca (r = 0.66) and Ni (r = 0.77) with a statistical significance (p < 0.05) were observed except for Na, Cr, Pb, K, Fe and Zn (p > 0.05). The observed positive correlation may suggest a possible influence of trace metals on PBDE concentrations in leachates. Furthermore, a test of relationship between major anions and PBDEs yielded positive relationship with Cl(-) (r = 0.94, p = 0.16), F(-) (r = 0.97, p = 0.21), Br(-) (r = 0.6, p = 0.29) and NO3 (2-) (r = 0.96, p = 0.08) with an insignificant statistical difference. However, evaluation of the relationship between some water quality parameters (pH, dissolved oxygen and electrical conductivity) gave negative correlation with PBDE concentrations.

Differences in health symptoms among residents living near illegal dump sites in Los Laureles Canyon, Tijuana, Mexico: a cross sectional survey

Living near landfills is a known health hazard prompting recognition of environmental injustice. The study aim was to compare self-reported symptoms of ill health among residents of four neighborhoods, living in haphazardly constructed settlements surrounded by illegal dumpsites in Tijuana, Mexico. One adult from each of 388 households located in Los Laureles Canyon were interviewed about demographics, health status, and symptoms. Distance from each residence to both the nearest dumpsite and the canyon bottom was assessed. The neighborhoods were selected from locations within the canyon, and varied with respect to proximity to dump sites. Residents of San Bernardo reported significantly higher frequencies of ill-health symptoms than the other neighborhoods, including extreme fatigue (OR 3.01 (95% CI 1.6-5.5)), skin problems/irritations (OR 2.73 (95% CI 1.3-5.9)), stomach discomfort (OR 2.47 (1.3-4.8)), eye irritation/tears (OR 2.02 (1.2-3.6)), and confusion/difficulty concentrating (OR 2.39 (1.2-4.8)). Proximity to dumpsites did not explain these results, that varied only slightly when adjusted for distance to nearest dumpsite or distance to the canyon bottom. Because San Bernardo has no paved roads, we hypothesize that dust and the toxicants it carries is a possible explanation for this difference. Studies are needed to further document this association and sources of toxicants.

Long-range atmospheric transport of persistent organic pollutants to remote lacustrine environments

Concentrations, temporal trends and fluxes of persistent organic pollutants (POPs: PAHs, PCBs and PBDEs) were determined in soil and (210)Pb-dated sediment cores from remote lacustrine environments (El Tule and Santa Elena lakes) in rural areas of Central Mexico. In both areas, the concentrations of target analytes in soil and sediment samples were comparable and indicative of slightly contaminated environments. The prevalence of low-molecular-weight PAHs in soils suggested their mainly atmospheric origin, in contrast to the aquatic sediments where runoff contribution was also significant. Increasing contamination trends of PCBs and PBDEs were evident, showing maximum fluxes of 4.8 ± 2.1 and 0.3 ± 0.1 ng cm(-2) a(-1) for PCBs and PBDEs, respectively. The predominance of lower-brominated PBDEs and lower-chlorinated PCBs in soils and sediments indicated that their presence is mostly due to long-range atmospheric transport.

Concentrations of persistent organic pollutants (POPs) in human blood samples from Mexico City, Mexico

Studies in Mexico have demonstrated exposure to persistent organic pollutants (POPs) in people living in different sites through the country. However, studies evaluating exposure to POPs in people living in Mexico City (one of most contaminated places in the world) are scarce. Therefore, the aim of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) in the blood as exposure biomarkers in people living in Mexico City. A total of 123 participants (blood donors aged 20-60 years) were recruited during 2010 in Mexico City. Quantitative analyses of blood samples were performed using gas chromatography coupled with mass spectrometry. Levels of the assessed compounds ranged from non-detectable (<LOD) to 350 ng/g lipid; from 8.20 to 91.0 ng/g lipid and from <LOD to 34.0 ng/g lipid for total PBDEs, total PCBs and total DDT, respectively. The current study indicates POP exposure in the people assessed and highlights the need for further biomonitoring studies of these POPs in the region. In this regard, biomonitoring of toxins on a global scale may be the first step towards the prevention of toxin-induced illnesses in the population.

Occurrence, characteristics and leakage of polybrominated diphenyl ethers in leachate from municipal solid waste landfills in China

Raw leachate samples were collected from various municipal solid waste (MSW) landfills in a densely populated city in North China to measure the levels and compositional patterns of polybrominated diphenyl ethers (PBDEs) in leachate. The total concentration of PBDEs ranged from 4.0 to 351.2 ng/L, with an average of 73.0 ng/L. BDE-209 dominated the congeners in most of the samples, followed by BDE-47 and -99. Higher PBDEs concentrations were found in leachate from younger landfill facilities in the urban area. Pearson correlation analysis implied a potential dependence of the PBDEs level on landfill age, suspended solids and dissolved organic carbon, while the results of principal component analysis (PCA) suggested potential origins and transportation of PBDEs in leachate. The Monte Carlo method was adopted to estimate the annual leakage of PBDEs into the underground environment nationwide, based on two main scenarios: simple landfills with inadequate liner systems and composite-lined landfills with defective geomembranes.

Elevated serum polybrominated diphenyl ethers and alteration of thyroid hormones in children from Guiyu, China

Informal electronic waste (e-waste) recycling results in serious environmental pollution of polybrominated diphenyl ethers (PBDEs) and heavy metals. This study explored whether there is an association between PBDEs, heavy metal and key growth- and development-related hormones in children from Guiyu, an e-waste area in southern China. We quantified eight PBDE congeners using gas chromatographic mass spectrometry, lead and cadmium utilizing graphite furnace atomic absorption spectrometry, three thyroids with radioimmunoassay and two types of growth hormones by an enzyme-linked immune-sorbent assay (ELISA) in 162 children, 4 to 6 years old, from Guiyu. In blood, median total PBDE was 189.99 ng/g lipid. Lead and cadmium concentrations in blood averaged 14.53±4.85 µg dL-1 and 0.77±0.35 µg L-1, respectively. Spearman partial correlation analysis illustrated that lead was positively correlated with BDE153 and BDE183. Thyroid-stimulating hormone (TSH) was positively correlated with almost all PBDE congeners and negatively correlated with insulin-like growth factor binding protein-3 (IGFBP-3), whereas free triiodothyronine (FT3) and free thyroxine (FT4) were negatively correlated with BDE154. However, no correlation between the hormones and blood lead or cadmium levels was found in this study. Adjusted multiple linear regression analysis showed that total PBDEs was negatively associated with FT3 and positively associated with TSH. Notably, FT4 was positively correlated with FT3, house functions as a workshop, and father's work involved in e-waste recycling and negatively correlated with vitamin consumptions. TSH was negatively related with FT4, paternal residence time in Guiyu, working hours of mother, and child bean products intake. IGFBP-3 was positively correlated with IGF-1 and house close to an e-waste dump. These results suggest that elevated PBDEs and heavy metals related to e-waste in Guiyu may be important risk factors for hormone alterations in children.

Synthesis and characterization of bromophenol glucuronide and sulfate conjugates for their direct LC-MS/MS quantification in human urine as potential exposure markers for polybrominated diphenyl ethers

Bromophenol glucuronide and sulfate conjugates have been reported to be products of mammalian metabolism of polybrominated diphenyl ethers (PBDEs), a group of additive flame-retardants found ubiquitously in the environment. In order to explore their occurrence in human urine, four water-soluble bromophenol conjugates, namely, 2,4-dibromophenyl glucuronide, 2,4,6-tribromophenyl glucuronide, 2,4-dibromophenyl sulfate, and 2,4,6-tribromophenyl sulfate, were synthesized, purified, and characterized. An analytical protocol using solid-phase extraction and ion-paired liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) quantification has been developed for the direct and simultaneous determination of these glucuronide and sulfate conjugates in human urine samples. The limit of detections for all analytes were below 13 pg mL(-1), with 73-101% analyte recovery and 7.2-8.6% repeatability. The method was applied to analyze 20 human urine samples collected randomly from voluntary donors in Hong Kong SAR, China. All the samples were found to contain one or more of the bromophenol conjugates, with concentration ranging from 0.13-2.45 μg g(-1) creatinine. To the best of our knowledge, this is the first analytical protocol for the direct and simultaneous monitoring of these potential phase II metabolites of PBDEs in human urine. Our results have also suggested the potential of these bromophenol conjugates in human urine to be convenient molecular markers for the quantification of population exposure to PBDEs.

Assessment of the levels of polybrominated diphenyl ethers in blood samples from Guadalajara, Jalisco, Mexico

The purpose of this study was to measure levels of polybrominated diphenyl ethers (PBDEs) in the blood of children (50 individuals) living in Guadalajara, Jalisco, Mexico. We analyzed six PBDE congeners by gas chromatography-mass spectrometry. Total PBDE levels ranged from not detectable (nd) to 15.2 μg/L on a whole-weight basis and from nd to 6,435 ng/g lipid on a lipid-weight basis. The dominant congener in our study was BDE-153, followed by BDE-154, BDE-99, BDE-100, and BDE-47. Levels of BDE-209 were below the detection limit. Our data indicate that children living in the areas studied in this work are exposed to high levels of PBDEs.

Maternal transfer of BDE-47 to offspring and neurobehavioral development in C57BL/6J mice

Polybrominated diphenyl ethers (PBDEs) are flame retardants used worldwide in a variety of commercial goods, and are now widely found in both environmental and biological samples. BDE-47 is one of the most pervasive of these PBDE congeners and therefore is of particular concern. In this study C57BL/6J mice were exposed perinatally to 0.03, 0.1 or 1mg/kg/day of BDE-47, a dose range chosen to encompass human exposure levels. Tissue levels of BDE-47 were measured in the blood, brain, fat and milk of dams and in whole fetal homogenate and blood and brain of pups on gestational day (GD) 15, and postnatal days (PNDs) 1, 10 and 21. From GD 15 to PND 1 levels of BDE-47 increased within dam tissues and then decreased from PNDs 1 to 21. Over the period of lactation levels in dam milk were comparatively high when compared to both brain and blood for all dose groups. Measurable levels of BDE-47 were found in the fetus on GD 15 confirming gestational exposure. From PNDs 1 to 21, levels of BDE-47 in pup tissue increased over the period of lactation due to the transfer of BDE-47 through milk. Behavioral tests of fine motor function and learning and memory were carried out between postnatal weeks 5-17 in order to evaluate the neurobehavioral toxicity of BDE-47. Behavioral deficits were only seen in the Barnes spatial maze where mice in the three exposure groups had longer latencies and traveled longer distances to find the escape hole when compared to vehicle control mice. These results support the conclusions that perinatal exposure to BDE-47 can have neurodevelopmental consequences, and that lactational exposure represents a significant exposure risk during development.

State of polybrominated diphenyl ethers in China: an overview

Polybrominated diphenyl ethers (PBDEs), extensively used as flame retardants, are ubiquitous environmental contaminants that are found in both abiotic and biotic environmental samples. Sufficient evidence shows that PBDEs have been rapidly accumulating in the environment of China, especially in the Southeast regions. This paper summarizes and critically reviews the published scientific data on PBDEs in China, including the levels of PBDEs in the air, soil, water, sediment, the terrestrial and marine organisms, and human samples in China. The data preliminarily reveal the state of PBDEs in China.

Exposure to toxic metals and persistent organic pollutants in Inuit children attending childcare centers in Nunavik, Canada

Arctic populations are exposed to substantial levels of environmental contaminants that can negatively affect children's health and development. Moreover, emerging contaminants have never been assessed in Inuit children. In this study, we document the biological exposure to toxic metals and legacy and emerging persistent organic pollutants (POPs) of 155 Inuit children (mean age 25.2 months) attending childcare centers in Nunavik. Blood samples were analyzed to determine concentrations of mercury, lead, polychlorinated biphenyls (PCBs), pesticides, brominated flame retardants [e.g., polybrominated diphenyl ethers (PBDEs)] and perfluoroalkyl and polyfluoroalkyl substances [PFASs; e.g. perfluorooctanesulfonate (PFOS) and perfluorooctane (PFOA)]. Lead [geometric mean (GM) 0.08 μmol/L], PCB-153 (GM 22.2 ng/g of lipid), BDE-47 (GM 184 ng/g of lipid), PFOS (GM 3369 ng/L), and PFOA (GM 1617 ng/L) were detected in all samples. Mercury (GM 9.8 nmol/L) was detected in nearly all blood samples (97%). Levels of metals and legacy POPs are consistent with the decreasing trend observed in Nunavik and in the Arctic. PBDE levels were higher than those observed in many children and adolescents around the world but lower than those reported in some U.S. cities. PFOS were present in lower concentrations than in Nunavimmiut adults. There is a clear need for continued biomonitoring of blood contaminant levels in this population, particularly for PBDEs and PFASs.

Polybrominated diphenyl ethers (PBDE) in blood of children in Baden-Württemberg between 2002/03 and 2008/09

Polybrominated diphenyl ethers (PBDE) are used in high amounts as flame retardants in plastic materials and textiles. Due to their persistence, their accumulation in the food chain and their toxic properties they have been integrated in the human biomonitoring program of the Baden-Württemberg State Health Office since 2002. In repeated cross-sectional studies in winter 2002/03 (n=162), 2004/05 (n=194), 2005/06 (n=411) and 2008/09 (n=770) blood samples of 9-11-year-old pupils were taken, pooled and analysed for PBDE after extraction and purification by silica gel using HRGC/HRMS. Samples were pooled according to region, gender, and breast feeding. PBDE in the pooled samples ranged from 1.9 to 12.5 ng/g blood fat (sum of all PBDE). Mean concentrations of PBDE, calculated for the four investigation periods, were 6.2 ng/g (2002/03), 5.4 ng/g (2004/05), 7.8 ng/g (2005/06) and 6.7 ng/g (2008/09). While the concentration of the decabrominated diphenyl ether (BDE-209) increased, the concentration of other congeners (BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183) decreased slightly or remained at the same level. Consistent differences with respect to gender and breast-feeding were not recognizable. Concentrations of PBDE in children range on the same level as in adults and do not seem to be critical from the toxicological point of view. Because of the slight increase of BDE 209, the internal concentrations of BDE should be monitored in the future. The strong variations in PBDE concentration between the different pooled samples indicate that, apart from ingestion, other routes of exposure (dermal, inhalation) and additional sources (textiles, building materials) must be taken into consideration.

A comparison of PBDE serum concentrations in Mexican and Mexican-American children living in California

BACKGROUND

Polybrominated diphenyl ethers (PBDE), which are used as flame retardants, have been found to be higher in residents of California than of other parts of the United States.

OBJECTIVES

We aimed to investigate the role of immigration to California on PBDE levels in Latino children.

METHODS

We compared serum PBDE concentrations in a population of first-generation Mexican-American 7-year-old children (n = 264), who were born and raised in California [Center for Health Analysis of Mothers and Children of Salinas (CHAMACOS) study], with 5-year-old Mexican children (n = 283), who were raised in the states in Mexico where most CHAMACOS mothers had originated (Proyecto Mariposa).

RESULTS

On average, PBDE serum concentrations in the California Mexican-American children were three times higher than their mothers' levels during pregnancy and seven times higher than concentrations in the children living in Mexico. The PBDE serum concentrations were higher in the Mexican-American children regardless of length of time their mother had resided in California or the duration of the child's breast-feeding. These data suggest that PBDE serum concentrations in these children resulted primarily from postnatal exposure.

CONCLUSIONS

Latino children living in California have much higher PBDE serum levels than their Mexican counterparts. Given the growing evidence documenting potential health effects of PBDE exposure, the levels in young children noted in this study potentially present a major public health challenge, especially in California. In addition, as PBDEs are being phased out and replaced by other flame retardants, the health consequences of these chemical replacements should be investigated and weighed against their purported fire safety benefits.

Environmental exposure to POPs and heavy metals in urban children from Dhaka, Bangladesh

Persistent organic pollutants (POPs) and heavy metals are well known environmental pollutants. Even though numerous studies have been carried out to assess human exposures to these compounds, there is still a lack of data on humans from developing countries, especially in underprivileged children. The objective of this study was to assess the exposure to POPs and heavy metals in children from Dhaka, Bangladesh. One specific aim was to investigate whether children working at, or living close to, open waste disposal sites (WDSs) were more heavily exposed than other urban children. In 2008, blood and serum were collected from 73 children aged 7-16 from five neighbourhoods. Some of the children lived and worked at WDSs (N = 31), others lived next to a WDS (N = 17), whereas some children lived far from such sites (N = 25). Blood levels of lead (B-Pb), cadmium (B-Cd), and selenium (B-Se) were determined by ICP-MS for all subjects. The metal levels were high, with B-Pb overall mean 120 μg L(-1) (range 40-220), B-Cd 0.74 μg L(-1) (0.22-4.1), and B-Se 120 μg L(-1) (81-170). There were no marked differences between children from the different neighbourhoods, or between WDS workers and other children. PCB levels were low and with no contrast between neighbourhoods, for CB-153 the overall mean was 7.0 ng g(-1) fat (2.8-51). In contrast, high levels of DDTs were observed in all children, for 4,4'-DDE 1300 ng g(-1) fat (420-4600), and for 4,4'-DDT 326 ng g(-1) fat (44-1400), indicating ongoing exposure. PBDE levels were low, and BDE-209 was quantitated mainly in children working at or living close to WDSs. In conclusion, the high levels of DDTs, lead and cadmium observed in children from Dhaka are of concern. Many children were exposed at levels where health effects have been observed, or at levels without safety margins.

Childhood obesity and environmental chemicals

Childhood and adolescent rates of obesity and overweight are continuing to increase in much of the world. Risk factors such as diet composition, excess caloric intake, decreased exercise, genetics, and the built environment are active areas of etiologic research. The obesogen hypothesis, which postulates that prenatal and perinatal chemical exposure can contribute to risk of childhood and adolescent obesity, remains relatively underexamined. This review surveys numerous classes of chemicals for which this hypothesis has been explored. We focus on human data where they exist and also discuss the findings of rodent and cell culture studies. Organochlorine chemicals as well as several classes of chemicals that are peroxisome proliferator-activated receptor agonists are identified as possible risk factors for obesity. Recommendations for future epidemiologic and experimental research on the chemical origins of obesity are also given.

Polybrominated diphenyl ether (PBDE) in blood from children (age 9-12) in Taizhou, China

Polybrominated diphenyl ethers (PBDEs) as ubiquitous persistent organic pollutants have attracted much attention in recent years. Exposure to PBDEs could induce a high health risk for children. The aim of this study was to investigate the PBDEs exposure of children (9-12 years) from Taizhou, China. Fifty-eight blood samples were collected in one school in a mountainous area in Taizhou. The concentrations of sigma9PBDEs (sum of BDE-28, -47, -99, -100, -153, -154, -183, -197 and -209) ranged from 2.66 to 33.9 ng/g lipid wet (lw) with a median of 7.22 ng/g lw. These concentrations were lower than those of children in USA, but close to European and Asian general population levels. The results showed that children in Taizhou countryside were at a low level of PBDEs exposure. The predominant congener was BDE-209, followed by BDE-28, -47, -197 and -153. High abundance of BDE-209 was consistent with the pollution background of PBDEs in China characterized by high brominated congeners as main pollutants.

Is decabromodiphenyl ether (BDE-209) a developmental neurotoxicant?

Polybrominated diphenyl ether (PBDE) flame retardants have become ubiquitous environmental pollutants. The relatively higher body burden in toddlers and children has raised concern for their potential developmental neurotoxicity, which has been suggested by animal studies, in vitro experiments, and recent human epidemiological evidence. While lower brominated PBDEs have been banned in several countries, the fully brominated decaBDE (BDE-209) is still utilized, though manufacturers will discontinue production in the U.S.A. in 2013. The recent decision by the U.S. Environmental Protection Agency to base the reference dose (RfD) for BDE-209 on a developmental neurotoxicity study has generated some controversy. Because of its bulky configuration, BDE-209 is poorly absorbed and does not easily penetrate the cell wall. Its acute and chronic toxicities are relatively low, with the liver and the thyroid as the primary targets, though there is some evidence of carcinogenicity. A few animal studies have indicated that BDE-209 may cause developmental neurotoxicity, affecting motor and cognitive domains, as seen for other PBDEs. Limited in vivo and in vitro studies have also evidenced effects of BDE-209 on thyroid hormone homeostasis and direct effects on nervous cells, again similar to what found with other lower brominated PBDEs. In contrast, a recent developmental neurotoxicity study, carried out according to international guidelines, has provided no evidence of adverse effects on neurodevelopment, and this should be considered in a future re-evaluation of BDE-209. While estimated exposure to BDE-209 in children is believed to be several orders of magnitude below the most conservative RfD proposed by the USEPA, questions remain on the extent and relevance of BDE-209 metabolism to lower brominated PBDEs in the environment and in humans.

A global review of polybrominated diphenyl ether flame retardant contamination in birds

As a consequence of substantial, long-term usage, polybrominated diphenyl ethers (PBDEs) have contaminated humans, wildlife, and abiotic matrices around the world. Although several reports have reviewed PBDE contamination in general, none have focused specifically on birds. Birds have long been recognized as invaluable monitoring species for organohalogen contamination. This review summarizes most available PBDE data in birds and emphasizes several specific aspects, i.e., inter-regional differences in PBDE contamination, the extent of BDE-209 contamination, differences in congener composition patterns between piscivorous and terrestrial-feeding birds, trophic biomagnification and temporal changes in PBDE contamination. A meta-analysis of PBDE congener profiles reveals distinctly different patterns between birds utilizing terrestrial and aquatic food webs. Terrestrial-feeding birds appear to exhibit heightened Deca-BDE contamination. Inter-regional comparisons reveal elevated PBDE burdens in North American aquatic birds compared to those from the rest of the world, likely related to greater Penta-BDE demand there. Examination of North American and Chinese terrestrial birds also exhibited some of the highest BDE-209 concentrations ever reported in wildlife, and suggested that urban environments in general and some commercial activities (e.g., electronic recycling) may increase exposure of wildlife and humans to Deca-BDE. Summaries of temporal trend studies suggest that varying usage histories and regulations have influenced PBDE contamination patterns at different regions. As a consequence of continued usage of Deca-BDE around the world, significant increases in BDE-209 burdens have been observed in both North American and European birds. Examination of both wild and laboratory-exposed birds also indicated potential degradation of BDE-209 to less brominated, but more bioavailable/toxic congeners. Therefore, it would be wise to reduce releases of Deca-BDE, the only PBDE formulation remaining in production, to the environment.

Halogenated flame retardants: do the fire safety benefits justify the risks?

Since the 1970s, an increasing number of regulations have expanded the use of brominated and chlorinated flame retardants. Many of these chemicals are now recognized as global contaminants and are associated with adverse health effects in animals and humans, including endocrine and thyroid disruption, immunotoxicity, reproductive toxicity, cancer, and adverse effects on fetal and child development and neurologic function. Some flame retardants such as polybrominated diphenyl ethers (PBDEs) have been banned or voluntarily phased out by manufacturers because of their environmental persistence and toxicity, only to be replaced by other organohalogens of unknown toxicity. Despite restrictions on further production in some countries, consumer products previously treated with banned retardants are still in use and continue to release toxic chemicals into the environment, and the worldwide use of organohalogen retardants continues to increase. This paper examines major uses and known toxic effects of commonly-used organohalogen flame retardants, replacements for those that have been phased out, their combustion by-products, and their effectiveness at reducing fire hazard. Policy and other solutions to maintain fire safety while reducing toxicity are suggested. The major conclusions are: (1) Flammability regulations can cause greater adverse environmental and health impacts than fire safety benefits. (2) The current options for end-of-life disposal of products treated with organohalogens retardants are problematic. (3) Life-cycle analyses evaluating benefits and risks should consider the health and environmental effects of the chemicals, as well as their fire safety impacts. (4) Most fire deaths and most fire injuries result from inhaling carbon monoxide, irritant gases, and soot. The incorporation of organohalogens can increase the yield of these toxic by-products during combustion. (5) Fire-safe cigarettes, fire-safe candles, child-resistant lighters, sprinklers, and smoke detectors can prevent fires without the potential adverse effects of flame retardant chemicals. (6) Alternatives to organohalogen flame retardant chemicals include using less flammable materials, design changes, and safer chemicals. To date, before evaluating their health and environmental impacts, many flame retardant chemicals have been produced and used, resulting in high levels of human exposure. As a growing literature continues to find adverse impacts from such chemicals, a more systematic approach to their regulation is needed. Before implementing new flammability standards, decision-makers should evaluate the potential fire safety benefit versus the health and environmental impacts of the chemicals, materials, or technologies likely to be used to meet the standard. Reducing the use of toxic or untested flame retardant chemicals in consumer products can protect human and animal health and the global environment without compromising fire safety.

Distribution of PCDD/Fs, PCBs, PBDEs and organochlorine residues in children's blood from Zhejiang, China

Concentrations and congener specific profiles of PCDD/Fs, PCBs, PBDEs and organochlorine residues were measured in 22 pooled blood samples representing 66 children from both polluted areas (E-waste recycling region) and case control areas in Zhejiang province, China. To our knowledge, this is the first report on these pollutants in the blood of Chinese children. The mean concentrations of [summation operator]PCDD/Fs, [summation operator]PCBs, [summation operator]PBDEs, HCB and pp'-DDE in pooled blood samples from polluted areas (Luqiao) were 206+/-157 pg g(-1) lipid, 40.6+/-7.01 ng g(-1) lipid, 32.1+/-17.5 ng g(-1) lipid, 14.6+/-20.1 ng g(-1) lipid and 108+/-21.8 ng g(-1) lipid, respectively. WHO-TEQ-2005 for PCBs and PCDD/Fs were 11.9+/-4.62 pg g(-1) lipid and 10.3+/-6.39 pg g(-1) lipid, respectively. The results showed that PCBs, PBDEs and organochlorine residues in the E-waste recycling area were significantly (P<0.001) higher than the case control areas. High levels of PCDD/Fs were detected in the case control area (Longyou), where Na-PCP had been widely sprayed to prevent snailborne schistosomiasis. The contamination levels and profiles were compared with those documented in previous publications.

Levels and patterns of polybrominated diphenyl ethers in children's plasma from Dalian, China

Polybrominated diphenyl ethers (PBDEs) are potential persistent organic pollutants which have raised many concerns in recent years. Research focusing on children exposure to PBDEs is important but insufficient. The levels and patterns of PBDEs in children's plasma from Dalian, China were studied for the first time. Seventeen PBDE congeners (BDE-30, 28, 35, 37, 75, 47, 66, 100, 99, 116, 155, 154, 153, 183, 181, 190 and 209) in 29 plasma samples were measured. Median PBDE concentration was 31.61 ng g(-1) lipid. BDE-153 was the dominant congener, followed by BDE-99, 47, and 183. High abundance of BDE-183 suggested a higher Octa-BDE use in China. No significant differences were observed between males and females or among different age groups. The levels of PBDEs in children's plasma in the present study were 9-30 times higher than those in non-occupational exposure people from Guangzhou, South China and those in human milk of general adults from other cities of China, but were at the moderate levels of those in children around the world. These results indicate that children in Dalian are at a high risk of exposure to PBDEs.

Polybrominated diphenyl ethers in marine ecosystems of the American continents: foresight from current knowledge

Polybrominated diphenyl ethers (PBDEs) are a class of synthetic halogenated organic compounds used in commercial and household products, such as textiles, furniture, and electronics, to increase their flame ignition resistance and to meet fire safety standards. The demonstrated persistence, bioaccumulation, and toxic potential of these compounds in animals and in humans are of increasing concern. The oceans are considered global sinks for PBDEs, as higher levels are found in marine organisms than in terrestrial biota. For the past three decades, North America has dominated the world market demand for PBDEs, consuming 95% of the penta-BDE formulation. Accordingly, the PBDE concentrations in marine biota and people from North America are the highest in the world and are increasing. Despite recent restrictions on penta- and octa-BDE commercial formulations, penta-BDE containing products will remain a reservoir for PBDE release for years to come, and the deca-BDE formulation is still in high-volume use. In this paper, we review all available data on the occurrence and trends of PBDEs in the marine ecosystems (air, water, sediments, invertebrates, fish, seabirds, and marine mammals) of North and South America. We outline here our concerns about the potential future impacts of large existing stores of banned PBDEs in consumer products, and the vast and growing reservoirs of deca-BDE as well as new and naturally occurring brominated compounds on marine ecosystems.