Geographic variation of chlorinated pesticides, toxaphenes and PCBs in human milk from sub-arctic and arctic locations in Russia

Forty-Year Biomonitoring of Environmental Contaminants in Russian Arctic: Progress, Gaps and Perspectives

This article presents a comprehensive survey of the studies on the biomonitoring of persistent organic pollutants (POPs) and metals in biota and human tissues on the territory of the Russian Arctic. It is concluded that a relatively small number of studies were carried out during the last 40 years; for several Russian Arctic regions there is no data up to date, and for some regions the data are scarce, with most of the studies carried out in 1990s, followed by the large-scale GEF/AMAP/RAIPON project of 2001-2004 covering four regions. After that, single projects have been implemented in a few regions. Only the Nenets okrug and the Chukotka okrug (and hardly the Murmansk oblast) can be attributed as the regions where the biomonitoring of contaminants was carried out during last decades on several occasions, and for which the content of POPs and metals in biota and the human organism was assessed in 12-15-year dynamic trends (at least "at three points"). For the rest of the Russian Arctic territories, only fragmentary "cross-sections" of biomonitoring data is available, mainly obtained in the 1990s or early 2000s, which do not allow judging either the dynamics of the processes or the current state of affairs. The overwhelming majority of the studies in the Russian Arctic (more than 90%) were carried out within the framework of international projects, i.e., with cofinancing, assistance and contribution (including laboratory analyses) from the foreign colleagues and partners. The shortcomings of the Russian system of biomonitoring, including the weakness of the laboratory and research base, are considered. Perspectives of the Russian Arctic biomonitoring are discussed in detail, with the proposal of the elaboration of the national Russian Arctic Contaminants Program (RACP).

Pesticide residues in breast milk and the associated risk assessment: A review focused on China

This review aims to provide an overview of studies on pesticide residues in breast milk in China and the related health risk to mother and infants. Results showed that the investigations of breast milk covered 22 provincial administrative regions of China. Beijing and some densely populated and economically developed areas have most publications. The study frequency was followed the order of DDTs>HCHs>HCB > ∑Drins,∑Chlordane. While the residue levels were ranked as DDTs, HCHs > ∑Drins>HCB > ∑Chlordane. The highest residue levels of DDTs and HCHs in breast milk were found in 1980s (~10,000 ng/g lipid), then experienced a sharp decrease in 1990s (~1000-2000 ng/g lipid). In 2000s and 2010s, DDTs, and HCHs residue still showed a decreasing trend. Spatially, people located in urban area, coastal areas and southern China tend to have higher pesticide residues as compared to rural area, inland area and northern China, respectively. Other factors such as dietary habit, living environment, the maternal age, the parity, body mass index, lactation period, menstruation characteristics as well as hormonal drug intake and infertility treatment will also affect the pesticide residues in breast milk of Chinese people. According to the estimated daily ingestion (EDI) of breast milk, the average health risk for infants were generally exceeded the acceptable level before 2006, while after that, most EDI values were within the standard. Body burden of pesticides in mother can also be evaluated by using the residue data in breast milk, but no relevant guidelines were available. Other knowledge gap included 1) for some provinces with large consumption of pesticides or located in remote and plateau areas, there are few/no studies available; 2) current study on pesticide residues in breast milk in China were only focused on organochlorine pesticides, research on current used pesticides (such as pyrethroids, organophosphorus, carbamate) were necessary in the future.

Levels of polychlorinated biphenyls in human milk samples in European countries

Polychlorinated biphenyls (PCBs) are persistent pollutants, harmful to human health, which enter the human body mainly through food and bind to body fat. For these reasons their use in most countries is prohibited. Human milk has an advantage over other types of human samples in measuring human exposure to PCBs, as it is obtained with non-invasive sampling methods. In Europe, including Croatia, PCB levels have been monitored for many years. This review summarises PCB trends in human milk across Europe. The trend is generally downward, with higher levels prevailing in urban areas near industrial plants. The highest PCB levels were reported in the Czech Republic and Slovakia.

The levels of polycyclic aromatic hydrocarbons (PAHs) in human milk and exposure risk to breastfed infants in petrochemical industrialized Lanzhou Valley, Northwest China

We investigated in this paper the presence of PAHs in human milk from lactating women residing in Lanzhou, a petrochemical industrialized valley city in Northwest China. The PAH concentration levels in human milk samples from 98 healthy women were determined by gas chromatography/mass spectrometry (GC/MS). The associations between the lifestyle factors and the PAHs levels of human milk were analyzed. Moreover, we applied principal component analysis (PCA) method to gain a better insight into the similarities or dissimilarities of the human milk PAH loads and different pathways of source exposure. In addition, the exposure risks of breastfed infants due to PAH ingestion via breast milk were assessed and the relative breast-feeding risk to the total intake dose of infants was addressed. The results showed that the average fat-normalized human milk ∑₁₅PAHs concentrations for the lactating women residing in four districts of Lanzhou, namely, Xigu, Anning, Qilihe, and Chengguan were 320.40, 270.36, 374.04, and 259.84 ng/g of fat, respectively. The ∑₁₅PAHs of human milk from the lactating women of Qilihe District exhibited the highest concentration level, while the concentration level for women from Xigu District is the second highest for the observed human milk ∑₁₅PAHs. And the corresponding BaPeq concentrations for women in Xigu, Anning, Qilihe, and Chengguan districts were 58.29, 47.95, 65.13, and 45.60 ng/g of fat, respectively. A significant correlation was only found between human milk and living district environment (p < 0.05). Although the Spearman correlation analysis showed that there were no significant correlation existing between other lifestyle and human milk PAHs, we confirmed that consuming barbecue food could elevate PAHs levels in human milk: the barbecue intake frequency caused 10% fluctuation of ∑₁₅PAHs concentration between high frequency and low frequency group in our study. Furthermore, the exposure to second-hand smoke can also increase the ∑₁₅PAHs levels in human milk by 4 to 11% here. Ingestion doses of PAHs by infants (19.37-77.75 ng kg^-1 day^-1) were much higher than the inhalation doses (2.83-16.48 ng kg^-1 day^-1), which indicated that the ingestion is the main exposure risk pathway for infants. Since there are limited guidelines and standards for PAHs ingestion dose in human milk by infant, we compared the ingestion dose of BaP with the upper bound estimates of BaP dietary exposure of 108 ng kg^-1 day^-1 for toddlers of ages between 1.5 and 2.5 years of age in the UK reported by Committee on Toxicity of Chemicals in Food (COT) and the data we obtained were lower than this upper bound. However, the estimated margin of exposure (MOE) values of BaP-MOE, PAH2-MOE, PAH4-MOE, and PAH8-MOE were smaller than 10,000 which indicated that there are potential hazard for breastfed infants consuming these human milk samples.

Inhibitor of Differentiation-3 and Estrogenic Endocrine Disruptors: Implications for Susceptibility to Obesity and Metabolic Disorders

The rising global incidence of obesity cannot be fully explained within the context of traditional risk factors such as an unhealthy diet, physical inactivity, aging, or genetics. Adipose tissue is an endocrine as well as a metabolic organ that may be susceptible to disruption by environmental estrogenic chemicals. Since some of the endocrine disruptors are lipophilic chemicals with long half-lives, they tend to bioaccumulate in the adipose tissue of exposed populations. Elevated exposure to these chemicals may predispose susceptible individuals to weight gain by increasing the number and size of fat cells. Genetic studies have demonstrated that the transcriptional regulator inhibitor of differentiation-3 (ID3) promotes high fat diet-induced obesity in vivo. We have shown previously that PCB153 and natural estrogen 17β-estradiol increase ID3 expression. Based on our findings, we postulate that ID3 is a molecular target of estrogenic endocrine disruptors (EEDs) in the adipose tissue and a better understanding of this relationship may help to explain how EEDs can lead to the transcriptional programming of deviant fat cells. This review will discuss the current understanding of ID3 in excess fat accumulation and the potential for EEDs to influence susceptibility to obesity or metabolic disorders via ID3 signaling.

PCBs and OCPs in human milk in Eastern Siberia, Russia: Levels, temporal trends and infant exposure assessment

The aim of our study is to investigate the spatial distribution of polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (p,p'-DDT) and its metabolites, α- and γ-isomers of hexachlorocyclohexane (HCH) in 155 samples of human milk (HM) from Eastern Siberia (six towns and seven villages in Irkutsk Region, one village of the Republic of Buryatia and one town in Zabaikal'sk Region, Russia), and to examine the dietary and social factors influencing the human exposure to the organochlorines. The median and range of the concentration of six indicator PCBs in HM in 14 localities in Eastern Siberia (114 (19-655) ng g^-1 lipids respectively) are similar to levels in the majority of European countries. However, in one village, Onguren, the median and range of levels of six indicator PCBs (1390 (300-3725) ng g^-1 lipids) were comparable to levels measured in highly contaminated populations. The Lake Baikal seals are highly exposed to persistent organic pollutants (POPs) and could be a potential source of PCB and DDT exposure in the Onguren cohort via the consumption of the Lake Baikal seal tissue. The location of food production in areas exposed to the emissions of local POP sources can also significantly influence POP levels in HM samples from industrialized areas. Estimated daily intakes (EDI) of HCH and HCB for infants are considerably lower or close to acceptable daily intake (ADI). The EDI of total DDTs and total PCBs are higher than ADI.

Relationship between e-waste recycling and human health risk in India: a critical review

Informal recycling of waste (including e-waste) is an emerging source of environmental pollution in India. Polychlorinated biphenyls (PCBs), polychlorinated diphenyl ethers (PBDEs), and heavy metals, among other substances, are a major health concern for workers engaged in waste disposal and processing, and for residents living near these facilities, and are also a detriment to the natural environment. The main objective of this review article was to evaluate the status of these impacts. The review found that, huge quantity of e-waste/waste generated, only a small amount is treated formally; the remainder is processed through the informal sector. We also evaluated the exposure pathways, both direct and indirect, and the human body load markers (e.g., serum, blood, breast milk, urine, and hair), and assessed the evidence for the association between these markers and e-waste exposure. Our results indicated that the open dumping and informal e-waste recycling systems should be replaced by the best available technology and environmental practices, with proper monitoring and regular awareness programs for workers and residents. Further and more detailed investigation in this area is also recommended.

Hexachlorocyclohexane (HCH) in human blood in the south of the Russian Far East

The content of organochlorine pesticides in blood of residents of the Russian Far East is assessed. Among hexachlorocyclohexane isomers, only β-HCH has been found. This fact indicates that contamination of the environment and human organisms by this pesticide began long ago. Its concentration varies from 2060 to 22,230 ng/g lipid. The probable sources of the toxicant found in human organisms are discussed.

Levels of PCDD/Fs, PCBs and PBDEs in breast milk of women living in the vicinity of a hazardous waste incinerator: assessment of the temporal trend

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were determined in breast milk from women living in the vicinity of a hazardous waste incinerator (HWI) in Catalonia, Spain. The results were compared with the levels obtained in previous surveys carried out in the same area in 1998 (baseline study), 2002 and 2007. The current total concentrations of 2,3,7,8-chlorinated PCDD/Fs in breast milk ranged from 18 to 126 pg g(-1)fat (1.1-12. 3 pg WHO2005-TEQPCDD/F), while the total levels of PCBs ranged from 27 to 405 pg g(-1)fat(0.7-5.3 pg WHO2005-TEQPCB). In turn, PBDE concentrations (sum of 15 congeners) ranged 0.3-5.1 g g(-1)fat, with a mean value of 1.3 ng g(-1)fat. A general decrease in the concentrations for PCDD/Fs, both planar and total PCBs, and PBDEs in breast milk was observed. The levels of PCDD/Fs, PCBs, and PBDEs in milk of women living in urban zones were higher than those corresponding to industrial zones (41%, 26%, and 8%, respectively). For PCDD/Fs and PCBs, the current decreases are in accordance with the reduction in the dietary intake of these pollutants that we have also observed in recent studies carried out in the same area of study.

Extraction and clean-up methods for organochlorine pesticides determination in milk

Organochlorine pesticides (OCPs) can cause environmental damage and human health risks since they are lipophilic compounds with high resistance to degradation and long half-lives in humans. As most persistent OCPs have been banned years ago, it is expected to find these compounds at trace levels in environment. Therefore, increasingly sensitive and reliable analytical techniques are required to ensure effective monitoring of these compounds. The aim of this review is to discuss extraction and clean-up methods used to monitor OCP residues in milk, reported in the last 20 years. To carry out this review, an exhaustive bibliographic review was conducted. Despite the disadvantages of conventional extraction and clean-up methods, such as liquid-liquid, solid-phase or Soxhlet extractions, these procedures are still used due to their reliability. New extraction methods, like solid-phase microextraction, matrix solid-phase dispersion or QuEChERS, have not been thoroughly evaluated for OCP determination in milk. Almost all the methodologies analyzed in this review presented good performance characteristics according to the performance acceptability criteria set in SANCO's procedure. Comparison between limits of quantification (LOQ) and detection (LOD), for the reported methodologies, is not always possible due to the heterogeneity of the units. Thus, researchers should take into account an homogenization of LOD and LOQ units, according to the international regulations and MRLs established. Finally, more research is necessary to obtain the ideal methodology for OCPs determination in milk, which comprises the environmentally friendly characteristics of the new techniques and the reliability of the traditional methodologies.

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in blood and breast milk collected from pregnant women in Sapporo City, Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), and non-dioxin-like PCBs in paired samples of blood and breast milk collected from 67 secundiparas in Sapporo City, Japan, and combined this data with those of the 30 secundiparas previously measured. The arithmetic mean total toxic equivalents (TEQ-WHO) concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of the 97 secundiparous subjects were 3.0-23 (mean: 13, median: 14) and 2.7-20 (mean: 8.6, median: 8.5) pg TEQ g(-1) lipid, respectively. The sums of the concentrations of 56 non-dioxin-like PCB congeners that were measured in the subjects' blood and breast milk were 16-326 (mean: 107, median: 100) and 12-252 (mean: 73, median: 67) ng g(-1) lipid, respectively. The partitioning ratios of individual congeners of PCDDs, PCDFs, dioxin-like PCBs, and non-dioxin-like PCBs from blood to breast milk in secundiparas were almost the same as those of primiparas that have been recently reported, suggesting that the partitioning ratios of these compounds from maternal blood to breast milk in women is little affected by delivery. Furthermore, the partition of PCB congeners with chlorine at the 2-, 3-, 4'-, and 5-positions or the 2-, 4-, 4'-, and 5-positions of the biphenyl ring from the blood to the breast milk tended to occur at a higher level than that of other congeners. In particular, the levels of tetraCB-74 and hexaCB-146 in the breast milk for both primiparous and secundiparous mothers were slightly higher than those in the blood.

Polycyclic aromatic hydrocarbon residues in human milk, placenta, and umbilical cord blood in Beijing, China

This paper provides the results of an investigation on dietary intakes and internal doses of polycyclic aromatic hydrocarbons (PAHs) for nonsmoking women from Beijing, China. Concentrations of PAHs were measured by gas chromatography/mass spectrometry (GC/MS) for human milk, placenta, and umbilical cord blood samples from 40 nonsmoking women and for 144 composite food samples covering major food categories. Information on food consumption and estimated ingestion doses of PAHs by the cohort was also collected individually. Relationship among the studied human samples and relative importance of breastfeeding to the total exposure dose of infants were addressed. The median (mean and standard deviation) total concentrations of 15 PAHs in human milk, placenta, and umbilical cord blood with (or without) fat normalization were 278 (9.30 ± 5.75), 819 (35.9 ± 15.4), and 1370 (5.521 ± 3.71) ng/g of fat, respectively, and the corresponding levels of benzo[a]pyrene equivalent (B[a]P(equiv)) were 11.2 (0.473 ± 0.605), 16.2 (0.717 ± 0.318), and 13.1 (0.140 ± 0.225) ng/g of fat, respectively. The calculated intake of B[a]P(equiv) by Beijing cohort varied from 0.609 to 4.69 ng·kg(-1)·day(-1) with a median value of 1.93 (2.09 ± 0.921 mean ± standard deviation) ng·kg(-1)·day(-1). Significant correlations were found among human milk, placenta, and umbilical cord blood (p < 0.05) for low-molecular-weight PAHs, indicating selective transfer potential of individual PAHs from mother to fetus. Internal dose of PAHs was not in proportion to amounts of food ingestion, daily dietary intake, lifestyle, and social-demographic characteristics of the participants (p > 0.05). Ingested doses of PAHs (3.00-102 ng·kg(-1)·day(-1)), which were much higher than the inhaled doses (0.152-8.50 ng·kg(-1)·day(-1)), were 3-4 orders of magnitude lower than the recommended reference doses, unlikely to impose any obvious risk based on current knowledge.

PCDD/Fs and dioxin-like PCBs in human milk and estimation of infants' daily intake: a review

This paper reviews the recent scientific literature on PCDDs, PCDFs and dioxin-like PCBs in human milk. All the papers reporting levels of these contaminants in human breast milk published from January 2000 to January 2009 and available on the www.sciencedirect.com web site were identified and included. The aim was (1) to study levels of PCDDs, PCDFs and PCBs in human milk in mothers from different geographical areas and assess infant exposure to these contaminants; (2) to study the effect of variables such as the mother's age, number of deliveries, dietary and smoking habits and her own nutrition in infancy, and the environment, on levels of the contaminants in breast milk; (3) to study time patterns, and (4) to identify data gaps.

Body burden of POPs of Hong Kong residents, based on human milk, maternal and cord serum

This study is one of the very few investigating the body burdens of persistent organic pollutants in residents of Hong Kong. Twenty-nine human milk samples and 21 human blood (and cord blood) samples collected from 2005 were analyzed for PAHs, OCPs and PCBs levels. Higher levels of PAHs, DDTs and PCBs were detected in human milk samples when compared to maternal serum and cord serum (PAHs: milk: 1981 ng g⁻¹ fat, maternal serum: 1461, cord serum: 1158; DDTs: 3099, 1934, 1556; PCBs: 49, 41, 40). Among the 16 PAHs, naphthalene (human milk: 786 ng g⁻¹ fat, maternal serum: 331, cord serum: 348), phenanthrene (361, 144, 193), pyrene (187, 154, 98) and fluoranthene (158, 128, 89) were the major PAHs detected in three human tissues. p,p'-DDE and p,p'-DDT were the only metabolites of DDT detected in the three types of human tissues. High detection rate of the p,p'-DDE and p,p'-DDT (> 90%) were noted in the three types of human samples. On the contrary, low detection frequency of PCBs in human milk (10.7%), maternal serum (1.7%) and cord serum (0.8%) were observed. The correlation coefficients of the PAHs, DDTs and PCBs levels in the three types of human tissues together with fish consumption, maternal age and tissue fat were analyzed. The following significant correlations were observed: Σ DDTs and p,p'-DDE in human milk with consumption of freshwater and marine fish, and maternal age; Σ PCBs in human milk with marine fish consumption, and maternal age; Σ PAHs in human milk with maternal age, respectively. The estimated daily intakes of DDTs by infants indicated that 7 out of 29 of the human milk samples exceeded 20 ng g⁻¹ day⁻¹, the tolerable daily intake (TDI) proposed by the Health Canada Guideline in terms of DDTs levels. The high intake of DDTs by infants may be of concern as infants are more susceptible to the adverse effects imposed by various environmental contaminants. Human milk is a reliable and comparatively non-invasive tool for monitoring body loading of POPs, which also allows health risk assessment of residual chemicals on our next generation.

Levels and patterns of Persistent Organic Pollutants (POPS) in selected food items from Northwest Russia (1998-2002) and implications for dietary exposure

Residues of persistent organic pollutants (POPs) were analysed in 70 selected food items from Northwest Russia in 1998-2002. Levels of PCBs ranged from 0.2 to 16ng/g wet weight (ww) in dairy products and fats, 0.2 to 23ng/g ww in meat products, 0.5 to 16ng/g ww in eggs and 0.3 to 30ng/g ww in fish. High levels of DDT (16ng/g ww) were found in locally produced butter from Kola Peninsula, in pork fat from Arkhangels region (10 to 130ng/g ww) and in some fish samples from White Sea and Kargopol region (17 and 30ng/g ww). Findings of low DDE/DDT ratios in many of the studied food items indicated recent contamination to DDTs. Mean levels of sum TEQs(WHO1998) of dioxin-like mono-ortho PCBs: PCBs 105, 118, 156 and 157 (∑mo-PCBs-TEQs(WHO1998)) were highest in dairy products, chicken eggs and fish, with levels of 0.292, 0.245 and 0.254pg/g ww, respectively. The estimated daily intake (EDI) for ∑mo-PCBs-TEQs(WHO1998) was 0.74pg/kgbw/day and in the same range as in Sweden and Denmark. Fish, dairy products, eggs and meat were the main contributors to the EDI of ∑mo-PCBs-TEQs(WHO1998). The EDIs of DDTs, HCHs and HCB were several times higher than in Sweden and Denmark. Consumption of meat and poultry were important sources for intake of DDTs and HCHs, respectively. Contamination of animal feed and agricultural practice were assumed the most important causes for the results in the present study. However, increased control on maximum residue levels in food and feed may have resulted in large changes on levels and patterns of POPs in food in the studied areas.

Relationship between the concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in maternal blood and those in breast milk

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), and non-dioxin-like PCBs in paired samples of blood and breast milk collected from 89 primiparous mothers in Sapporo City, Japan, and studied the relationships of these compounds between blood and breast milk for these women plus 30 primiparous mothers in whom these data had been previously reported. The present study is one of the few studies in which the concentration distributions of PCDDs, PCDFs, dioxin-like PCBs, and non-dioxin-like PCBs have been investigated in blood and breast milk collected from the same mothers. The arithmetic mean TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of these 119 subjects were 8.2, 2.9, 5.1, and 0.4 pg TEQ g(-1)lipid, respectively, and 4.8, 2.0, 4.0, and 0.4 pg TEQ g(-1)lipid, respectively, with the total TEQ concentrations of these dioxin-like compounds being 7.0-36 (mean: 17, median: 14) and 5.7-41 (mean: 11, median: 10) pg TEQ g(-1)lipid, respectively. The sums of the concentrations of 56 non-dioxin-like PCB congeners that were measured in the subjects' blood and breast milk were 43-445 (mean: 120, median: 106) and 34-366 (mean: 90, median: 81) ng g(-1)lipid, respectively, indicating that the total TEQ concentration and the total concentration of 56 non-dioxin-like PCB congeners in the maternal blood were notably higher than those in the breast milk. Statistically significant correlations were observed between maternal age and the total TEQ concentration of PCDDs, PCDFs, and dioxin-like PCBs or the total concentration of 56 non-dioxin-like PCB congeners in maternal blood, and significant correlations were also observed between maternal age and the total TEQ concentration of these dioxin-like compounds or the total concentration of 56 PCB congeners in breast milk. The total TEQ concentration of PCDDs, PCDFs, and dioxin-like PCBs in maternal blood showed a close correlation to that in subjects' breast milk, and there was also good correlation between the total concentration of 56 non-dioxin-like PCB congeners in maternal blood and that in subjects' breast milk. Pearson and Spearman correlation analyses showed a relationship between the total TEQ concentration of PCDDs, PCDFs, and dioxin-like PCBs and the total concentration of 56 non-dioxin-like PCB congeners in maternal blood, and also showed an association between the total TEQ concentration of these dioxin-like compounds and the total concentration of 56 PCB congeners in breast milk. The concentration of hexaCB-153 in maternal blood showed significant correlations to the total TEQ concentration of PCDDs, PCDFs, and dioxin-like PCBs or the total concentration of 56 non-dioxin-like PCBs in that sample. Moreover, the concentration of hexaCB-153 in breast milk also showed significant correlations to the total TEQ concentration of these dioxin-like compounds or the total concentration of 56 PCB congeners in that sample. These findings suggested that hexaCB-153 may be an indicator of total TEQ concentrations of PCDDs, PCDFs, and dioxin-like PCBs and total concentrations of 56 non-dioxin-like PCB congeners in blood and breast milk of primiparous mothers.

Levels and regional trends of persistent organochlorines and polybrominated diphenyl ethers in Asian breast milk demonstrate POPs signatures unique to individual countries

Human breast milk samples collected in 2007-2008 from four countries, Vietnam (Hanoi), China (Beijing), Korea (Seoul) and Japan (Sendai, Kyoto and Takayama), were analyzed for persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane-related compounds (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Comparing with previous surveys, the present study indicates that the DDTs in breast milk from China and Vietnam had gradually decreased during the last decade, but were still 5-10 times higher than those in other nations. The ratios of p,p'-DDE/p,p'-DDT and o,p'-DDT/p,p'-DDT were higher in Beijing than in the other countries, suggesting that there is less fresh intake of commercial DDT products and a possible exposure to dicofol in China. CHL and PCB levels were relatively higher in mothers from Japan, whereas beta-HCH and HCB were more common in Chinese women. In Japan, it is suspected that mothers in the urban/coastal area (Sendai) were more continuously exposed to organochlorine pesticides (OCPs) than mothers in the rural/inland area (Takayama). In addition, OCP levels in primiparae were significantly higher than those in multiparae from Japan and Korea. These indicate that both parity and regional factors are major determinants of the levels of OCPs and PCBs in human milk. On the other hand, higher concentrations of PBDEs were observed in mothers' milk from Korea. The congener was dominated by BDE-47 (43-54%), followed by BDE-153 (23-33%) in all regions except for Beijing where BDE-28 (23%) was relatively abundant. In Japanese breast milk, regional and parity-dependent distributions were not observed for PBDEs. Among PBDE congeners, age-dependency was observed for BDE-153, which was negatively correlated (p<0.05) to the age of mothers in Kyoto (17 participants were housewives), while it increased with age in Sendai (10 participants were clerks). No such correlation was seen for BDE-47, indicating that BDE-47 was ingested and assimilated via different kinetics or routes from BDE-153 in Japan.

Levels of chlorinated pesticides and polychlorinated biphenyls in Norwegian breast milk (2002-2006), and factors that may predict the level of contamination

In the present study, polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in 423 breast milk samples from women living in Norway. Various predictors for the contaminant levels were also investigated. The samples were collected in six counties, representing South, Central and North Norway in 2002-2006. Initial results showed significantly lower levels of OCPs in breast milk from ethnic Norwegians (N=377) compared to ethnic non-Norwegians (N=46). Median concentrations (range) of PCBs, p,p'-DDE, HCB, beta-HCH and oxychlordane in breast milk of the Norwegian women, all parities included, were 103 (34-450), 41 (5.4-492), 11 (3.6-24), 4.7 (0.9-37) and 2.8 (0.5-16) ng/g lipid weight, respectively. Results indicated that sum of 18 PCBs, p,p'-DDE and beta-HCH are good predictors for monitoring of PCB, DDT and HCH levels in Norwegian breast milk. Multivariable linear regression analyses showed that age was strongly associated with increasing OC levels (P<0.001), whereas parity was associated with decreasing OC levels (P<0.001). Smoking was associated with higher levels of PCBs, p,p'-DDE and beta-HCH. The models explained from 17 to 35% of the variance. Median levels of OCs in the present Norwegian primparaes seemed to be 29-62% lower than corresponding results found in a Norwegian study from 2000-2002.

Dietary intake and human milk residues of hexachlorocyclohexane isomers in two Chinese cities

Residues of hexachlorocyclohexane isomers (HCHs, including alpha-HCH, beta-HCH, gamma-HCH, and delta-HCH) in human milk of two populations from Beijing and Shenyang, China were studied. In addition to human milk samples from 76 women, 271 composite food samples covering major food categories were also collected for HCH analysis. The food consumption and social-demographic characteristics of the studied populations were investigated and dietary intakes of HCHs of the milk donors on an individual basis were calculated. The dependences of HCH concentration in the human milk on food consumption, dietary intake of HCHs, and demographic characteristics were studied. It was found that beta-HCH dominated the HCHs detected in the human milk. Although there were dramatic declines in HCHs in the human milk compared to historical data, the current levels (312 +/- 377 ng/g fat and 360 +/- 235 ng/g fat as the means and standard deviations for Beijing and Shenyang, respectively) were still much higher than those reported in other cities within China and around the world. It was revealed that the residual level of HCHs in the human milk was positively correlated (p < 0.001) to the quantities of food consumption. Milk, oil, vegetables, and fruits contributed a large portion of HCHs intake in Beijing, while cereals, milk, vegetables, oil, and meat were the most important dietary intake sources of HCHs in Shenyang. Both daily dietary intake of HCHs (p < 0.001) and body mass index (BMI, body weight divided by the squared height) (p < 0.01) were significantly correlated with human milk HCHs. A nonlinear model was developed to predict the residues of HCHs in human milk using both dietary intake and BMI as independent variables. Potential risk of the HCH exposure of breastfed infants is discussed.

Organochlorine pesticide and polychlorinated biphenyl residues in human milk from the Southern Coast of Caspian Sea, Iran

In the present study, human milk was sampled in October 2006 from Nour and Noushahr cities and their countryside on the Southern Coast of Caspian Sea, Iran. They were analyzed for organochlorine pesticides, such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), alpha, beta and gamma-hexachlorocycloexane (HCH) isomers and six PCBs congeners (IUPAC Nos. 28, 52, 101, 138, 153 and 180). Average concentrations of HCHs, DDTs, PCBs and HCB were 3780, 2554, 1560 and 930 ng g(-1) lipid wt, respectively. There was no significant difference between the concentrations of investigated pollutants between the two cities and their countryside. No significant differences in OCPs and PCBs were found between primiparous and multiparous mothers. There was no correlation between levels of OCPs and PCBs in human milk and the age of mothers. There was a significant difference in the organochlorine levels, including DDTs, between mothers who have eaten fish once a week and those who consumed fish more than once (p>0.05). An analysis of the infant exposure to OCPs and PCBs via breast milk indicated that the daily intake rates for most of the mothers were above the guideline proposed by Health Canada which is definitely caused on children health for concern.

Population physiologically based pharmacokinetic modeling for the human lactational transfer of PCB-153 with consideration of worldwide human biomonitoring results

BACKGROUND

One of the most serious human health concerns related to environmental contamination with polychlorinated biphenyls (PCBs) is the presence of these chemicals in breast milk.

OBJECTIVES

We developed a physiologically based pharmacokinetic model of PCB-153 in women, and predict its transfer via lactation to infants. The model is the first human, population-scale lactational model for PCB-153. Data in the literature provided estimates for model development and for performance assessment.

METHODS

We used physiologic parameters from a cohort in Taiwan and reference values given in the literature to estimate partition coefficients based on chemical structure and the lipid content in various body tissues. Using exposure data from Japan, we predicted acquired body burden of PCB-153 at an average childbearing age of 25 years and compared predictions to measurements from studies in multiple countries. We attempted one example of reverse dosimetry modeling using our PBPK model for possible exposure scenarios in Canadian Inuits, the population with the highest breast milk PCB-153 level in the world.

RESULTS

Forward-model predictions agree well with human biomonitoring measurements, as represented by summary statistics and uncertainty estimates.

CONCLUSION

The model successfully describes the range of possible PCB-153 dispositions in maternal milk, suggesting a promising option for back-estimating doses for various populations.

Validation of dietary intake of dichlorodiphenyltrichloroethane and metabolites in two populations from Beijing and Shenyang, China based on the residuals in human milk

This paper presents the results of an investigation on association between dietary intakes and human milk concentrations of dichlorodiphenyltrichloroethane and metabolites (DDTs) of two populations from Beijing and Shenyang, China. We analyzed human milk samples from 76 women and 287 composite food samples covering major food categories for concentrations of DDTs. We also collected information on food consumptions and calculated dietary intakes of DDTs of the participants on individual basis. The median values of the measured DDTs in human milk were 125 ng/g lipid and 132 ng/g lipid for the samples from Beijing and Shenyang, respectively. The mean (+/-standard deviation) daily dietary intakes of DDTs by the two groups were 32.0 +/- 14.2 ng/kg day and 27.9 +/- 11.3 ng/kg day, respectively. The temporal trends of decreasing in DDTs and increasing in DDE/DDT ratio suggested that the residuals were primarily from historical application. We found a significant correlation between human milk concentration and daily dietary intake of DDTs, while the dietary intake could explain 22% of the variation in the DDTs in human milk. In addition to dietary exposure, we also found that maternal body mass index (body weight divided by the squared height), body weight, body height, and mother's age contributed significantly to the variation of DDTs in human milk after intake normalization. The result of a probabilistic risk assessment indicated that the exposure of infants to DDTs through breast feeding would be a public health concern for years to come, although breast feeding is still recommended.

Distribution of polychlorinated biphenyls and organochlorine pesticides in human breast milk from various locations in Tunisia: levels of contamination, influencing factors, and infant risk assessment

The concentrations of dichlorodiphenytrichloroethane and its metabolites (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), dieldrin, and 20 polychlorinated biphenyls (PCBs) were determined in 237 human breast milk samples collected from 12 locations in Tunisia. Gas chromatography with electron capture detector (GC-ECD) was used to identify and quantify residue levels on a lipid basis of organochlorine compounds (OCs). The predominant OCs in human breast milk were PCBs, p,p'-DDE, p,p'-DDT, HCHs, and HCB. Concentrations of DDTs in human breast milk from rural areas were significantly higher than those from urban locations (p<0.05). With regard to PCBs, we observed the predominance of mid-chlorinated congeners due to the presence of PCBs with high K(ow) such as PCB 153, 138, and 180. Positive correlations were found between concentrations of OCs in human breast milk and age of mothers and number of parities, suggesting the influence of such factors on OC burdens in lactating mothers. The comparison of daily intakes of PCBs, DDTs, HCHs, and HCB to infants through human breast milk with guidelines proposed by WHO and Health Canada shows that some individuals accumulated OCs in breast milk close to or higher than these guidelines.

Levels and temporal trends of chlorinated pesticides, polychlorinated biphenyls and brominated flame retardants in individual human breast milk samples from Northern and Southern Norway

Human breast milk samples from primipara women from Northern (Tromsø) (N=10) and Southern Norway (Oslo) (N=19) collected in 2000-2001 were analysed with respect to hexachlorobenzene (HCB), hexachlorocyclohexane (HCHs), chlordanes (CHLs), DDTs, mirex, toxaphenes (CHBs), polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and hexabromocyclododecane (HBCD). CHBs, PBDEs and HBCD were only analysed in the Tromsø samples. Sum-PCBs and sum-DDTs were the major organochlorines (OCs) (170 and 110 ng g(-1) lipid weight (lw), respectively). Other OCs were found in levels of approximately 10- to 300-fold lower than sum-PCBs. Overall, the concentrations of OCs followed the decreasing order of PCBs>DDTs>HCB>HCHs approximately CHLs>CHBs>mirex. Concentrations of sum-HCHs were significantly higher in breast milk from Oslo compared to Tromsø (p<0.05). The PCB profile was dominated by PCB-153, -138 and -180. The PBDE pattern was dominated by PBDE-47 and PBDE-153. The median level of sum-PBDEs was 4.1 ng g(-1) lw. PBDE-209 was detected in all analysed samples (median 0.13 ng g(-1) lw). The estimated daily intake (EDI) for the median (range) of sum mono-ortho (mo) PCBs(8) was 3.7 (1-9) pg TEQ kg(-1) body weight per day for breast fed infants in Norway. This exceeded the TDI by a factor of 1.8 (1-4) based only on intake of mono-ortho PCBs. The present study shows that concentrations of OCs in primipara breast milk have decreased 50-60% since 1991, and that this trend is continuing.

PCDD/F and PCB in human serum of differently exposed population groups of an Italian city

A chemical plant located in Brescia, an industrial city in North-Western Italy, produced polychlorobiphenyls (PCBs) during a 30-50 year period, causing widespread pollution of the surrounding agricultural area. This area contains several small farms, which principally produce veal meat for private consumption of the farmers' families. The pollution went undiscovered for many years, during which period contaminated food was regularly consumed. This paper reports the polychlorodibenzodioxin (PCDD), polychlorodibenzofuran (PCDF) and PCB levels of a serum sample pooled from the consumers of contaminated food, compared to six population groups of the city of Brescia. Four of these groups were selected in order to represent, respectively, the local general population and the residents of three zones of the polluted area, while the last two groups represented, respectively, the present and the former workers of the plant. One human milk sample from one of the consumers of contaminated food was also analyzed. Results show that the consumers of the contaminated food and the former workers of the plant display considerably higher levels than all other groups. The levels of general population and of all other groups were generally similar both to each other and to the range of literature values for unexposed populations. The respective contribution of PCDDs, PCDFs, mono-ortho and non-ortho PCBs (dioxin-like PCBs) to (Toxicity Equivalents) TEQ of the population groups of this study were also compared to literature data: the two groups with a high contamination level, together with the human milk sample, displayed a higher incidence of mono-ortho PCBs and a lower contribution of PCDD, possibly correlated with the source of contamination.

DDT and its metabolites in breast milk from the Madeira River basin in the Amazon, Brazil

Until the 1990s the 1,1,1-trichloro-bis-2,2'-(4chlorophenyl) ethane (DDT) was sprayed in the walls of the house along the Madeira River basin, Brazilian Amazon, a region well known for its large number of malaria cases. In 1910, Oswaldo Cruz described the presence of malaria in 100% of the population living in some localities from the Madeira River basin. Data available in the literature point to the DDT contamination in fishes captured in Madeira River region. Fish is the major source of dietary protein to these people. DDT tends to accumulate in lipid rich tissues and is being eliminated by different events, including lactation. Considering the importance of feeding breast milk to the children, the associated risks of DDT exposure via breast milk intake to children must be assessed. This is the main objective of this work: to analyse the presence of the p,p'-DDT and its metabolites p,p'-DDE and p,p'-DDD in 69 human milk samples and to estimate the intake of DDT and its metabolite in terms of total DDT (total DDT=p,p'-DDE+p,p'-DDD+p,p'-DDT). All the samples showed contamination with DDT and its metabolites ranging from 25.4 to 9361.9 ng of total DDT/g of lipid (median=369.6 ng of total DDT/g of lipid) and 8.7% of the estimated daily intake (EDI), in terms of total DDT, which was higher than the acceptable daily intake proposed by the WHO.

Determination of dioxins and polychlorinated biphenyls in breast milk, maternal blood and cord blood from residents of Tohoku, Japan

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are bioaccumulative chemicals that are considered to be toxic contaminants based on several epidemiological studies. To elucidate exposure levels of these chemicals in the present study, concentrations of PCDD/DFs, dioxin-like PCBs (DL-PCBs) and PCBs in breast milk, maternal blood and cord blood obtained from the same participants registered in a birth cohort study in Tohoku, Japan, were measured. Congener-specific analysis revealed several differences in minor congeners of these compounds among the three specimen types, although major congeners were detected in the specimens. The toxicity equivalence quantity concentrations (1998 WHO-TEF) and PCBs in breast milk, maternal blood and cord blood on the whole and on a lipid basis were in the order of breast milk > maternal blood > cord blood. Pearson's correlation coefficients of TEQs and total PCBs among the three specimens were high, with the correlation coefficient of TEQ between breast milk and maternal blood being the highest (r=0.94, p<0.001). On the other hand, the TEQ between breast milk and cord blood was the lowest (r=0.79, p<0.001). Pearson's correlation coefficient between the TEQ and PCBs in each specimen was also high (r=0.82-0.95, p<0.001). The associations of chemical concentrations with maternal age, parity, fish intake, BMI and the rate of body weight increase during pregnancy were analyzed with multiple linear regression analysis. TEQ concentrations and PCBs were negatively associated with parity (p<0.05), and maternal age was positively associated with PCBs (p<0.05). However, the associations with BMI and fish intake during pregnancy were not significant. These results suggest that parity is an important factor affecting the concentrations of dioxins and PCBs in these specimens.

Spatial and temporal changes of chlorinated pesticides, PCBs, dioxins (PCDDs/PCDFs) and brominated flame retardants in human breast milk from Northern Russia

This study presents for the first time temporal changes of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in Russian human breast milk samples. Concentrations of OCPs and PCBs in samples from three locations in the North West of Russia in 2000-2002 (n=42), were compared to corresponding levels measured in 1993-1996 (n=58). In addition brominated flame retardants (BFRs), consisting of polybrominated diphenylethers (PBDEs) (including BDE-209) and hexabromocyclododecane (HBCD) were analysed in samples from 2000-2002 (n=37). The present levels of SigmaDDTs and SigmaHCHs were 5 and 10 times higher than corresponding levels in the neighbouring country Norway. Median concentrations of SigmaHCHs (196 microg/kg lw), SigmaCHBs (19.7 microg/kg lw) and SigmaPCBs(16) (316 microg/kg lw) were highest in Murmansk. The percentage of p,p'-DDT to SigmaDDTs and ratio DDE/DDT suggest possible ongoing use of DDT in Russia. Levels of PBDE were low and dominated by the congeners BDE-47 and BDE-153. The deca brominated BDE-209 was detected in all analysed samples (median concentration 0.19 microg/kg lipid). Levels of SigmaOCPs and SigmaPCBs decreased 56 and 30% in Murmansk and 36 and 43% in Arkhangelsk during the study period. The decline of SigmaOCPs was significant at both locations (p<0.05-p<0.0001). For SigmaPCBs, the decreasing trend was only significant in Arkhangelsk (p<0.0001). In addition, a decline of Sigmatotal TEQs (SigmaTEQs of PCDDs/PCDFs, non-ortho- and mono-ortho PCBs) was observed in Murmansk and Arkhangelsk during the study period. The exposure of infants by PCDDs/PCDFs and dioxin-like PCBs is still exceeding the daily tolerable intake (TDI) in North West Russia. However, the concentrations of PCDDs/PCDFs and dioxin-like PCBs seem to decline very rapidly.

Persistent organochlorine pesticides in human milk samples from Australia

Human milk has been used as a surrogate for the assessment of body burden and exposure to persistent lipophilic organochlorine pesticides (OCPs). With the exception of restricted use of mirex, the use of persistent, lipophilic OCPs has been banned in Australia since the 1980s. The decline of human body burden of OCPs following their ban in many industrialised countries is well recorded worldwide from the 1970s until the 1990s though little is known on whether these trends are continuing. In this study, 157 human milk samples collected during 2002 and 2003 as well as 24 samples collected in 1993 were analysed as 20 regional pools for 17 OCPs. OCPs were detected in all pooled human milk samples from 2002/03 typically with highest concentrations of p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) (mean+/-standard deviation; median concentration 311+/-174; 279 ng g(-1) lipid) followed by beta-hexachlorocyclohexane (beta-HCH) (80+/-173; 21 ng g(-1) lipid). Other OCPs consistently detected included dieldrin (16+/-6; 17 ng g(-1) lipid), hexachlorobenzene (HCB) (18+/-16; 14 ng g(-1) lipid), transnonachlor (11+/-5; 9 ng g(-1) lipid) and p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) (9+/-6; 7 ng g(-1) lipid). The results from this study indicated that following a substantial decline of OCP concentrations from the early 1980s to the 1990s, little decline could be observed since then. Furthermore the use of multivariate statistics indicated some regional trends with slightly higher levels of the broadly used insecticides DDT and HCH in both historic and recent samples from Melbourne, whereas, sample pools collected from mothers that lived in rural Queensland and New South Wales as well as Adelaide and Sydney showed comparatively higher levels of heptachlor and dieldrin - both of which have been used for termite treatment. These results indicate that even 20 years after the discontinuation of usage, historical use of OCPs rather than exposure via global transport of OCPs is responsible for continuous low exposure in Australia.

Intra- and intercompartmental associations between levels of organochlorines in maternal plasma, cord plasma and breast milk, and lead and cadmium in whole blood, for indigenous peoples of Chukotka, Russia

Long-range transport of pollutants towards circumpolar regions emphasizes the need for up-to-date and reliable biological monitoring data. This paper explores the use, reliability and availability of maternal blood (MB) and plasma (MP), cord blood (CB) and plasma (CP) and mother's milk (MM) in terms of assessing exposure to persistent toxic substances (PTSs). It is concluded that MP has the best combination of availability, sensitivity in terms of number of PTSs, their detection frequency and concentrations, and physiological relevance. The study group consisted of 48 pregnant women of indigenous origin from the Chuchki district in the eastern Russian arctic. Blood, CB and MM specimens were collected from all women and MP, CP and MM were analyzed for the Arctic Monitoring and Assessment Programme (AMAP) suite of organochlorines (OCs) and metals (Pb and Cd in MB and CB). Generally speaking, the levels of PTSs coincided with those indicated in several AMAP publications from Chukotka and other areas of northern Russia. The correlations of PTS concentrations between the three body fluid compartments exceeded the minimum statistical requirements of alpha = 0.05 and beta = 0.20 for most of the compounds, with r > 0.46 except for Cd (r = 0.05); lipid adjustments for the OCs did not affect the r-values to any significant extent. The majority of the inter-OC correlations within compartments also fulfilled the indicated statistical condition. Careful consideration is given to the replacement of concentrations below the detection limit, OC detection frequency, the criteria for log-transformation of the data, analytical uncertainty, and biological variability. Practical implications of the findings are explored.

Organohalogen compounds in human breast milk from Republic of Buryatia, Russia

Human breast milk samples collected during 2003/04 in Buryatia, a Russian autonomous republic, were analyzed in order to assess human exposure to organohalogen compounds including organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). When compared with available worldwide data, levels of HCB (23-880 ng/g lipid wt.), PCBs (69-680 ng/g lipid wt.), and HCHs (100-3700 ng/g lipid wt.) were relatively high, indicating elevated human exposure to these organochlorines (OCs) in Buryatia. In contrast to OCs, PBDE concentrations were low (0.46-1.7 ng/g lipid wt.). Out of 14 BDE congeners analyzed, BDE-28, BDE-47, BDE-100, BDE-153, BDE-197, and BDE-207 were detected. Estimated daily intakes (EDIs) of HCHs, HCB, CHLs, and PCBs by infants solely from human milk for 100%, 43%, 34%, and 17% of the samples, respectively, exceeded guideline thresholds. Although high EDIs raise concern for possible toxic effects of OCs, women in Buryatia are recommended to breastfeed due to numerous advantages of breastfeeding for mother and child.

Development of a reference dose for the persistent congeners of weathered toxaphene based on in vivo and in vitro effects related to tumor promotion

Toxaphene is a mixture of chlorinated camphenes and bornanes that was produced and used in the United States until 1982. 1.3 million tons of toxaphene have been released worldwide. "Technical" toxaphene (TT) consists of a mixture of up to 800 different chemicals, known as congeners. TT weathers in the environment by both biotic and abiotic processes. The human body burden of toxaphene consists of only five persistent congeners that are not metabolized; three of these occur in considerably greater amounts than the other two. Because of the rapid metabolism and excretion of the non-persistent congeners, the persistent congeners that make up the human body burden most likely play a role in eliciting any potential adverse effects. EPA's toxicity assessment for TT is based on the occurrence of liver cancer in rodents, and considerable doubt exists whether this assessment is applicable to weathered toxaphene (WT). Using experimental results from European Union scientists, a reference dose (RfD) was developed for WT based on the three most persistent congeners that comprise the human body burden. The critical effect chosen was tumor promotion and this endpoint is considered protective for other endpoints as well. Although RfDs are typically derived for non-carcinogenic effects, the endpoint of tumor promotion is appropriate for RfD development because the experimental data suggest a dose threshold. The RfD for weathered toxaphene represented by the sum of the three major persistent congeners ( summation 3PC) is 2E-05 mg/kg-day. To apply this reference dose to a particular WT mixture, information is needed regarding the percentage of summation 3PC in the mixture.

Levels of organochlorine pesticides in human milk from central Taiwan

The present study determined the residues of organochlorine pesticides (OCPs) in human milk collected in central Taiwan between December 2000 and November 2001. The OCPs were analyzed by GC/MS for 36 human milk samples from healthy women ranging between 20 and 36 years of age. The predominant OCPs were p,p'-DDE, p,p'-DDT, alpha-CHL, heptachlor epoxide, heptachlor, beta-HCH, and gamma-HCH, with median levels of 228, 19, 7.4, 4.0, 2.3, 1.2, and 0.8 ng/g lipid, respectively. The residues of OCPs in human milk from central Taiwan were comparable to those described in results from Sweden, the United Kingdom, and Japan, and were significantly lower than those from investigations in Asian countries, including China, Thailand, Indonesia, and Vietnam. Low DDE/DDT ratio (mean=13.6, SD=6.54) indicated that residual OCPs in human milk mainly originate from past exposure. A notable decrease in DDT levels ( sigma DDT=333 ng/g lipid) in human milk was found in this study compared to results from the previous two decades ( sigma DDT=3,595 ng/g lipid). Hypothetically, the level of alpha-CHL was significantly associated with total TEQ levels in Taiwanese human milk because of the sources of food contaminant, i.e. animal fat. Based on low OCP levels in Taiwanese human milk and low estimated median daily intake of total DDTs for a breastfed infant (1,358 ng/kg/day) with the assumption of an infant weighting 4 kg and consuming 699 g milk per day in the first month after birth, the Taiwanese policy of breast-feeding promotion was supported.

The potential impact of climate on human exposure to contaminants in the Arctic

Many northern indigenous populations are exposed to elevated concentrations of contaminants through traditional food and many of these contaminants come from regions exterior to the Arctic. Global contaminant pathways include the atmosphere, ocean currents, and river outflow, all of which are affected by climate. In addition to these pathways, precipitation, animal availability, UV radiation, cryosphere degradation and human industrial activities in the North are also affected by climate change. The processes governing contaminant behaviour in both the physical and biological environment are complex and therefore, in order to understand how climate change will affect the exposure of northern people to contaminants, we must have a better understanding of the processes that influence how contaminants behave in the Arctic environment. Furthermore, to predict changes in contaminant levels, we need to first have a good understanding of current contaminant levels in the Arctic environment, biota and human populations. For this reason, it is critical that both spatial and temporal trends in contaminant levels are monitored in the environment, biota and human populations from all the Arctic regions.

Specific accumulation of organochlorines in human breast milk from Indonesia: levels, distribution, accumulation kinetics and infant health risk

This study determined concentrations of polychlorinated biphenyls (PCBs) and organochlorine compound (OC) pesticides in the milk samples of women from the general population in four locations of Indonesia. The most prevalent residues of OCs were DDTs, PCBs and hexachlorocyclohexane isomers (HCHs), whereas other OCs such as chlordane compounds (CHLs), tris(4-chlorophenyl)methane and hexachlorobenzene were lower. The levels of OCs varied between locations and individuals, with DDTs higher in suburban and rural areas than urban localities, may be due to the differences in food habits and sources between the individuals and locations. Data from Purwakarta site indicated continuing DDT exposure, which may confirm recent usage of DDT in Indonesia. A positive correlation was observed between concentration of OCs in human milk and age of mothers, primiparas women having higher OCs than multiparas, suggesting these parameters play an important role influencing the OC burdens in lactating women. Some individuals accumulated DDTs and HCHs in breast milk close to or even higher than the TDI (tolerable daily intake) guidelines proposed by Health Canada.

Hexachlorobenzene in the global environment: emissions, levels, distribution, trends and processes

Hexachlorobenzene (HCB) is considered here as a 'model persistent organic pollutant.' Data on its sources, emissions, environmental levels and distributions and trends are compiled and used to assess its fate and behaviour in the global environment. Consideration is given as to the extent to which it has undergone repeated air-surface exchange or 'hopping' to become globally dispersed, the balance between primary and secondary sources in maintaining ambient levels, and its ultimate sinks in the environment. Global production exceeded 100,000 tonnes and primary emissions to atmosphere probably peaked in the 1970s. There has been a consistent downward trend in the environment over the past 20 years. Temporal trends of HCB in the environment vary, dependent on time period measured, media studied and study location, but the average half-life from all the studies is approximately 9 years. Estimates are made of the contemporary burden in the environment; these range between 10,000 and 26,000 tonnes and are dominated by the loadings in treated and background soils, sediments and oceans. Estimates of the trends of HCB emissions from treated soils are derived. At its peak, the amount of HCB emitted from soil to air may have been in the hundreds to thousands of tonnes per year, which would have made it a significant source of HCB to the environment. Whilst the amount of HCB being emitted from contemporary soil is much lower, only a small amount of re-emission of HCB from soil to air is required to maintain contemporary air concentrations under the current primary emission scenario.

Persistent organochlorine compounds in human breast milk from mothers living in Penang and Kedah, Malaysia

This study determined the concentrations of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides, and tris(4-chlorophenyl) methane (TCPMe) in human breast milk samples collected in 2003 from primipara mothers living in Penang, Malaysia. OCs were detected in all the samples analyzed with DDTs, hexachlorocyclohexane isomers (HCHs), and PCBs as the major contaminants followed by chlordane compounds (CHLs), hexachlorobenzene (HCB), and TCPMe. The residue levels of DDTs, HCHs, and CHLs were comparable to or higher than those in general populations of other countries, whereas PCBs and HCB were relatively low. In addition, dioxins and related compounds were also detected with a range of dioxin equivalent concentrations from 3.4 to 24 pg-TEQs/g lipid wt. Levels of toxic equivalents (TEQs) were slightly higher than those in other developing countries but still much lower than those of industrialized nations. One donor mother contained a high TEQs level, equal to the mean value in human breast milk from Japan, implying that some of the residents in Malaysia may be exposed to specific pollution sources of dioxins and related compounds. No association was observed between OCs concentrations and maternal characteristics, which might be related to a limited number of samples, narrow range of age of the donor mothers, and/or other external factors. The recently identified endocrine disrupter, TCPMe, was also detected in all human breast milk samples of this study. A significant positive correlation was observed between TCPMe and DDTs, suggesting that technical DDT might be a source of TCPMe in Malaysia. The present study provides a useful baseline for future studies on the accumulations of OCs in the general population of Malaysia.

In Utero and Lactational Exposure to an Environmentally Relevant Organochlorine Mixture Disrupts Reproductive Development and Function in Male Rats1

We hypothesized that in utero and lactational exposure of male rats to a mixture of more than 15 organochlorines, resembling that found in blubber from northern Quebec seals, alters reproductive development and function. Female rats were gavaged with either corn oil (controls) or the organochlorine mixture in increasing doses (low, medium, and high) for 5 wk before mating and through gestation. Developmental effects were monitored in the male offspring from Postnatal Day (PND) 2 until PND 90. The high-dose mixture reduced the number of pups per litter, percentage of live offspring, and pup weights (P < 0.05). Because only three rats from the high-dose treatment survived, data from this group beyond PND 2 were not included in the statistical analyses. As assessed by the time of preputial separation, puberty was delayed in the pups from treated dams (P < 0.05). Testes weights in the medium-dose group were greater than those in controls on PND 21 (P < 0.05). Ventral prostate weights were lower for the medium-dose group on PND 60 (P < 0.05). On PND 90, weights of the epididymis, ventral prostate, and seminal vesicle of the medium-dose rats were reduced compared to those of controls (P < 0.05). On PND 90, sperm motility parameters assessed by computer-assisted sperm analysis were altered in the low- and medium-dose groups (P < 0.05). Testicular and epididymal morphology was severely affected in rats exposed to the high dose of the mixture. Serum testosterone, LH, FSH, prolactin, and total thyroxine levels did not differ because of organochlorine treatment. Therefore, in utero and lactational exposure to an environmentally relevant organochlorine mixture adversely affects the reproductive system of male rats, perhaps via antiandrogenic effects during testis development, suggesting a possible reproductive health hazard for humans and other species.

A review on the usage of POP pesticides in China, with emphasis on DDT loadings in human milk

This article attempts to review the usage of nine pesticides included in the 12 Stockholm Convention persistent organic pollutants (POPs) in China and to examine the extent of DDT contamination in human milk, focusing on the Chinese populations. By comparing all the data available concerning DDTs in human milk from 19 countries, it is revealed that the Chinese populations exhibit rather high concentrations of DDTs, due to the fact that China has been a major producer and consumer of DDTs in the past, and also uses DDT for vector control, resulting in higher background levels of DDTs in different ecological compartments. The high body loading of DDT in Chinese populations is also related to the high dietary intake due to contamination of food. When comparing the data obtained recently (1998-2002), the coastal populations such as Guangzhou (DDE+DDT 2.13 microgg(-1) fat), Hong Kong (2.87 microgg(-1) fat) and Dalian (2.13 microgg(-1) fat) contain higher concentrations of DDTs which may reflect the dietary difference of consuming more meat and fish, than other Chinese populations (Beijing 1.96 microgg(-1) fat; Shenyang 0.87 microgg(-1) fat). In general, the rather low ratio of DDE/DDT (e.g., 4.07 for Guangzhou) of the Chinese milk samples reflected the more recent releases of DDT. It is recommended to impose a tighter control on the use of DDT for vector control as well as for agricultural application, conduct regular monitoring of DDT concentrations in different ecological compartments which include air, water, sediment and biota. Human milk is a preferred indicator reflecting human body loadings of POPs including DDTs, as well as the risk which may impose on our next generation. A national wide survey is needed to investigate the intake of POPs, including POP pesticides, due to dietary differences, with a strong focus on the more sensitive populations, e.g., coastal residents who consume a large amount of fish.

Pesticides and children

Prevention and control of damage to health, crops, and property by insects, fungi, and noxious weeds are the major goals of pesticide applications. As with use of any biologically active agent, pesticides have unwanted side-effects. In this review, we will examine the thesis that adverse pesticide effects are more likely to occur in children who are at special developmental and behavioral risk. Children's exposures to pesticides in the rural and urban settings and differences in their exposure patterns are discussed. The relative frequency of pesticide poisoning in children is examined. In this connection, most reported acute pesticide poisonings occur in children younger than age 5. The possible epidemiological relationships between parental pesticide use or exposure and the risk of adverse reproductive outcomes and childhood cancer are discussed. The level of consensus among these studies is examined. Current concerns regarding neurobehavioral toxicity and endocrine disruption in juxtaposition to the relative paucity of toxicant mechanism-based studies of children are explored.

Effect of in vitro estrogenic pesticides on human oestrogen receptor α and β mRNA levels

Nine widely distributed pesticides were recently demonstrated to possess potential estrogenic properties in oestrogen receptor (ER) transactivation and/or E-screen assays. We tested the effect of these nine pesticides on the human ERalpha and ERbeta mRNA steady state levels in the mamma cancer fibroblast MCF-7BUS cells using on-line RT-PCR. Like 17beta-oestradiol (E2), fenarimol significantly decreased the ERalpha and increased the ERbeta mRNA level. Endosulfan and pirimicarb alone decreased the ERalpha mRNA level weakly. After co-exposure with E2, all the tested pesticides counteracted the E2-induced decrease of the ERalpha mRNA level, but only significantly for prochloraz, dieldrin, and tolchlofos-methyl. Alone no pesticides affected the ERbeta mRNA level significantly, but chlorpyrifos increased the mRNA level weakly. Co-exposure with E2 elicited a significant increased ERbeta mRNA level by prochloraz, fenarimol, endosulfan, dieldrin, and tolchlofos-methyl, whereas no significant effect of the carbamate pesticides on the ERbeta mRNA level was observed. This study demonstrated that organochlor and organophosphorous pesticides possess the ability to interfere with the ERalpha and ERbeta mRNA steady state levels.

Persistent organochlorine residues in human breast milk from Hanoi and Hochiminh City, Vietnam: contamination, accumulation kinetics and risk assessment for infants

Despite the ban on persistent organochlorines (OCs) in most of the developed nations, their usage continued until recently in many Asian developing countries including Vietnam, for agricultural purposes and vector-borne disease eradication programs. In this study, we collected human breast milk samples from the two big cities in Vietnam: Hanoi (n=42) and Hochiminh (n=44) and determined the concentrations of persistent OCs such as PCBs, DDT and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), chlordane compounds (CHLs) and tris-4-chlorophenyl-methane (TCPMe). The contamination pattern of OCs was in the order of DDTs > PCBs > HCHs > CHLs approximately HCB approximately TCPMe. Compilation of available data indicated that DDT residue levels in human breast milk from Vietnam were among the highest values reported for Asian developing countries as well as developed nations. This result suggests recent usage of DDTs in both north and south Vietnam. Interestingly, in both cities, the p,p'-DDT portion was higher in multiparas than those in primiparas. Considering the fact that the interval between the first and the second child of a mother in Vietnam is usually short, this result probably indicates continuous intake of DDTs in the population. Analysis of infant exposure to DDTs via breast milk suggested that the daily intake rates for number of individuals are close to or above the threshold for adverse effects which may raise concern on children health.

Maternal concentration of polychlorinated biphenyls and dichlorodiphenyl dichlorethylene and birth weight in Michigan fish eaters: a cohort study

BACKGROUND

Studies on maternal exposure to polychlorinated biphenyls (PCBs) reported inconsistent findings regarding birth weight: some studies showed no effect, some reported decreased birth weight, and one study found an increase in weights. These studies used different markers of exposure, such as measurement of PCBs in maternal serum or questionnaire data on fish consumption. Additionally maternal exposures, such as dichlorodiphenyl-dichloroethylene (DDE), which are related to PCB exposure and may interfere with the PCB effect, were rarely taken into account.

METHODS

Between 1973 and 1991, the Michigan Department of Community Health conducted three surveys to assess PCB and DDE serum concentrations in Michigan anglers. Through telephone interviews with parents, we gathered information on the birth characteristics of their offspring, focusing on deliveries that occurred after 1968. We used the maternal organochlorine (OC) measurement closest to the date of delivery as the exposure. Although one mother may have contributed more than one child, serum concentrations derived from measurements in different surveys could vary for different children from the same mother. The maternal DDE and PCB serum concentrations were categorized as follows: 0 -< 5 microg / L, 5 -< 15 microg / L, 15 -< 25 microg / L, >or=25 microg / L. Using repeated measurement models (Generalized Estimation Equation), we estimated the adjusted mean birth weight controlling for gender, birth order, gestational age, date of delivery as well as maternal age, height, education, and smoking status.

RESULTS

We identified 168 offspring who were born after 1968 and had maternal exposure information. We found a reduced birth weight for the offspring of mothers who had a PCB concentration >or=25 microg / L (adjusted birth weight = 2,958 g, p = 0.022). This group, however, was comprised of only seven observations. The association was not reduced when we excluded preterm deliveries. The birth weight of offspring was increased in women with higher DDE concentrations when controlling for PCBs; however, this association was not statistically significant.

CONCLUSION

Our results contribute to the body of evidence that high maternal serum PCB concentration may reduce the birth weight in offspring. However, only a small proportion of mothers may actually be exposed to PCB concentrations >or=25 microg / L.