First WHO/UNEP survey of the current concentrations of persistent organic pollutants in human milk in Morocco

The presence of persistent organic pollutants (POPs) in human milk is an indicator of the level of these substances in the environment and enables evaluation of the potential exposure of breastfed children. POPs concentrations in a Moroccan human milk pooled sample (59 donors) were determined for the first time by the WHO reference laboratory to provide a baseline and allow monitoring of the future trends for those persistent organohalogen compounds. Eighty-one different POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dioxins and furans (PCDD/Fs) were identified and quantified by using gas chromatography (GC) with an electron capture detector (ECD) and confirmed by gas chromatography-mass spectrometry (GC/LRMS). The obtained results showed that the sum of DDT (sum of o,p'-DDD, p,p'-DDD, o,p'-DDE, p,p'-DDE, o,p'-DDT, and p,p'-DDT) was 237.9 ng/g, representing 94.0% of all detected OCPs levels, with a dominance of p,p'-DDE, and p,p'-DDT. Cis-heptachlor epoxide, HCB, and HCH were found at much lower levels. PCB indicator level was 60.7 ng/g of lipid, with the dominance of PCB 138, PCB 153, and PCB 180, presenting 98.3% of the total. Among the 25 PBDE congeners quantified, BDE-47, BDE-153, BDE-197, and BDE-207 were the dominant congeners account for 15.4% of the total concentration of PBDE (1.3 pg/g lipid). The lipid-adjusted level of PCDD/Fs and dl-PCBs expressed in Toxic Equivalents (TEQs: 6.65 pg/g) were lower in comparison to those found in the other countries. In summary, detected POPs levels in Moroccan human milk were much lower compared to the other countries, reflecting the effectiveness of the compliance with Stockholm Convention requirements on eliminating or reducing emissions of selected POPs. Continued monitoring is needed for these compounds, for which this is the first data available, provided by the WHO/UNEP survey in Morocco.

WHO/UNEP global surveys of PCDDs, PCDFs, PCBs and DDTs in human milk and benefit-risk evaluation of breastfeeding

Since 1987, the World Health Organization (WHO) carried out global surveys on polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in human milk. This study presents a review of the three most recent surveys from 2000 to 2010, including DDT. The objective was to identify global quantitative differences and provide baseline information for 52 countries or provide time-trends for countries with previous data. Individual human milk samples were collected following a WHO-designed procedure and combined to form a national pooled sample. Here, we report global levels for PCDDs, PCDFs, PCBs and the sum of o,p'-DDT, p,p'-DDT, o,p'-DDE, p,p'-DDE, o,p'-DDD and p,p'-DDD (ΣDDTs). A concise risk-benefit evaluation related to human milk contamination with these persistent organic pollutants (POPs) was also done. Large global and regional differences were observed. Levels of PCDDs and PCDFs were highest in India and some European and African countries. PCB levels were highest in East and West Europe. The highest levels of ΣDDTs were found in less industrialized countries. A temporal downward trend for PCDDs, PCDFs and PCBs is indicated. A risk-benefit assessment indicates that human milk levels of PCDDs, PCDFs and PCBs are still significantly above those considered toxicologically safe, while ΣDDTs are below or around those considered safe. With respect to potential adverse health effects, a more dominant role of in utero exposure versus lactational exposure is indicated. If potential adverse effects are balanced against positive health aspects for (breastfed) infants, the advantages of breastfeeding far outweigh the possible disadvantages. Our observations provide a strong argument to plea for further global source-directed measures to reduce human exposure further to dioxin-like compounds.

Exposure patterns of UV filters, fragrances, parabens, phthalates, organochlor pesticides, PBDEs, and PCBs in human milk: correlation of UV filters with use of cosmetics

In order to assess potential risks of exposure to environmental chemicals, more information on concomitant exposure to different chemicals is needed. We present data on chemicals in human milk of a cohort study (2004, 2005, 2006) of 54 mother/child pairs, where for the first time, cosmetic UV filters, synthetic musks, parabens and phthalate metabolites were analyzed in the same sample along with persistent organochlor pollutants (POPs), i.e., organochlor pesticides and metabolites, polybrominated diphenylethers and polychlorinated biphenyls (PCBs). The two groups of chemicals exhibited different exposure patterns. Six out of seven PCB congeners and a majority of pesticides were present in all milk samples, with significant correlations between certain PCB congener and pesticide levels, whereas the cosmetic-derived compounds, UV filters, parabens and synthetic musks, exhibited a more variable exposure pattern with inter-individual differences. UV filters were present in 85.2% of milk samples, in the range of PCB levels. Comparison with a questionnaire revealed a significant correlation between use of products containing UV filters and their presence in milk for two frequently used and detected UV filters, 4-methylbenzylidene camphor and octocrylene, and for the whole group of UV filters. Concentrations of PCBs and organochlor pesticides were within ranges seen in Western and Southern European countries. For several POPs, mean and/or maximum daily intake calculated from individual concentrations was above recent US EPA reference dose values. Our data emphasize the need for analyses of complex mixtures to obtain more information on inter-individual and temporal variability of human exposure to different types of chemicals.

Residues of persistent organic pollutants (POPs) in human milk in Hong Kong

Data on pesticide body load in the south China region are scarce. Here, we report the concentrations of 24 persistent organic pollutants (POPs), in 10 pools of human milk samples, collected at 2-6weeks postpartum from 238 primiparous women living in Hong Kong and south China, who participated in the 2002-2003 WHO exposure study. Residues were determined by gas chromatography with electron capture detector and confirmed by gas chromatography with mass spectrometry. The mean levels of alpha-HCH (mean 0.6ngg(-1) fat), beta-HCH (940ngg(-1) fat), gamma-HCH (1.8ngg(-1) fat), dieldrin (1.0ngg(-1) fat) and HCB (21.8ngg(-1) fat) were much lower than the 1985 estimates. Mean levels of alpha-HCH, gamma-HCH, dieldrin, cis-heptachlor-epoxide (0.7ngg(-1) fat), sum-chlordane (6.1ngg(-1) fat), trans-nonachlor (12.0ngg(-1) fat), BDE 47 (1.9ngg(-1) fat) and sum PBDE (3.4ngg(-1) fat) were comparable to the international median levels of the 15 other countries participating in the 2002-03 WHO exposure study. Hong Kong had the highest level of beta-HCH, possibly a residual effect of previous high exposures in the 1970s. Body loads of beta-HCH and chlordane were lower among mothers with younger age while mothers born in mainland China had lower levels of beta-HCH, cis-heptachlor-epoxide, oxy-chlordane and trans-nonachlor. Levels of toxaphene, endrin, endosulfan, bromcyclene and nitrofen were not detected in all or almost all of the milk pools. Continuous monitoring of POPs in human milk, especially beta-HCH, is needed for surveillance and interpretation of time trends, and for linkage to strict enforcement of agricultural regulations.

Fourth WHO-coordinated survey of human milk for persistent organic pollutants (POPs): Belgian results

Persistent organic pollutants (POPs) are chemicals that accumulate in the food chain and are toxic to humans and wildlife. The fourth World Health Organization (WHO) survey on POP levels in human milk (2006-2009) aims to provide baseline and trend information on human exposure to POPs. So far Belgium participated in all three previous rounds (1988, 1992, 2001). Whereas the first three rounds focused on determination of dioxins and PCBs in pooled (mixed) samples, the fourth survey comprised the analyses of individual milk samples for nine "basic POPs" (chlorinated pesticides and indicator PCBs) and of pooled milk samples for "basic POPs", "advanced POPs" (dioxins and dioxin-like PCBs) and "optional POPs" (polybrominated diphenylethers [PBDEs], polybrominated dioxins and dibenzofurans [PBrDD/F], mixed halogenated dioxins and dibenzofurans [PXDD/F] and hexabromocyclododecane [HBCD]). For the Belgian participation human milk samples were collected during the summer of 2006 from 197 women between 18 and 30 years old distributed over all Belgian provinces. The individual samples were analyzed in a Belgian Laboratory for "basic" POPs. A pooled sample was made from 178 individual samples and analyzed by the WHO Reference Laboratory for the "basic, advanced and optional" POPs. The results indicate that most organochlorinated pesticides banned 25-30 years ago were below or around detection limits in Belgian human milk samples although DDE was still found at low levels in all samples. Over the last five years the levels of marker PCBs and PCDD/Fs in Belgian human milk decreased, respectively, by 58% and 39%. For some of the other emerging or older compounds recent international data are needed to allow comparison. This shows the importance of international studies as run by WHO.

DDT levels in human milk in Hong Kong, 2001-02

High levels of p,p'-DDT were detected in Hong Kong breast milk sampled in 1976 and 1985. Monitoring DDT levels in human breast milk in this region is important to identify trends in exposure. As part of the 2002-03 WHO/EURO coordinated exposure study, the concentrations of DDT and its metabolites were determined in 10 pooled milk samples classified by geographic origin and dietary history, comprising milk samples from 238 primiparous mothers giving birth in Hong Kong. Analysis was performed by Gas Chromatography (GC) with electron capture detector and confirmed by GC/Mass Spectrometry. The sum-DDT concentration (range: 0.92-2.05 mg/kg fat) was age-dependent and indicated a decreasing trend since the 1970s. Mothers who recently came from mainland China had higher p,p'-DDT to p,p'-DDE ratios, suggesting a more recent exposure compared to women mainly residing in Hong Kong. The average Hong Kong sum-DDT level (1.50 mg/kg fat) was among the highest of the contemporary levels (range: 0.12-1.97 mg/kg fat; median: 0.40 mg/kg fat) in the 16 countries/regions participating in the 2002-03 WHO/EURO exposure study. This is probably due to the previous extensive DDT exposure and continuing use of DDT in agriculture in mainland China. Despite the apparent decrease of DDT body load over 30 years, the environmental health hazard from DDT contamination in the Pearl River Delta region remains a concern. Measures to eradicate illegal use of DDT in mainland China and regular food monitoring programs are needed in the region. Despite the presence of DDT and other persistent organic pollutants in human breast milk, breastfeeding should continue to be strongly supported for its life-long benefits to infants.