Occurrence of chlorinated and brominated dioxins/furans, PCBs, and brominated flame retardants in blood of German adults.

Persistent organic pollutants are widespread in the environment, and are associated with a particular health and ecological concern. The human body burden of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDDs/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenylether (PBDEs), and hexabromocyclododecanes (HBCDs) was determined. Blood samples were collected in Germany, originating from 42 randomly selected subjects between 20 and 68 years old. The median (95th percentile) concentrations, expressed as WHO2005-TEQ for PCDD/PCDFs and dioxin-like PCBs, were 6.2 (19.1) pg/g l.w. and 4.1 (8.8) pg/g l.w., respectively. PBDDs/Fs were found with a median of 2.8 pgTEQ/g l.w. and a 95th percentile of 8.7 pgTEQ/g l.w. (using similar interim TEF values as for PCDDs/Fs) On a median basis, the contribution of PCDD/Fs, dioxin-like PCBs, and PBDDs/Fs to total TEQ were 47%, 31%, and 21%, respectively. The sum of the 6 non-dioxin-like PCBs exhibited a median of 267ng/g l.w. and a 95th percentile of 834ng/g l.w. The median value for the sum of six tetra- to hepta-PBDE congeners was 1.7ng/g l.w. (95th percentile: 4.9ng/g l.w.). BDE 209 was the most abundant congener with a median of 1.8ng/g l.w. HBCDs were only found in some samples, and concentrations ranged between the limit of detection (5ng/g l.w.) and the limit of quantification (16ng/g l.w.). Results for PBDEs and HBCDs are comparable to other European studies. Our study demonstrated that the body burden of PCDD/Fs and PCBs declined continously since the last three decades, but exposure may exceed precautionary guideline levels.

Persistent and emerging pollutants in the blood of German adults: Occurrence of dechloranes, polychlorinated naphthalenes, and siloxanes.

Human biomonitoring is a valid method to determine exposure, identify time trends, and monitor the effects of restrictions and measures. To characterize the recent exposure of Germans to persistent or emerging substances, we analyzed 4 dechloranes, 33 polychlorinated naphthalenes (PCNs), and 3 cyclic volatile methyl siloxanes (cVMS) in 42 plasma samples. The samples were collected from blood donors on a random selection. The median values of both Dechlorane Plus (DDC-CO) isomers were 1.23ng/gl.w. for anti- and 0.77ng/gl.w. for syn-DDC-CO. The two other dechloranes were found at lower levels. The median level of ∑-PCNs was 575pg/gl.w. (range: 101-1406pg/gl.w.). On average, the levels of PCNs in plasma were dominated by the congeners CN73, CN66/67, and CN51, which were responsible for approximately 71% of the total amount of PCNs. The cVMS octa-, deca-, and dodecamethylcyclotetrasiloxane could be determined in only some samples, with maximum values of 0.73, 0.48, and 0.79µg/l, respectively. Regarding dechloranes, our results are similar to those from other western countries but slightly lower than results from China. The levels of PCNs in German blood are similar to those observed in the U.S.A., but considerably lower than those reported for Korea. Using a preliminary TEF (toxic equivalency factor), the mean TEQ of the 9 quantifiable PCNs in Germany was low (0.36pg TEQ/gl.w.). The PCN levels in our study group are lower compared to previous studies.

PCBs, PCDD/Fs, and PBDEs in blood samples of a rural population in South Germany.

The body burden of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like (dl-PCBs) and non-dioxin-like (ndl-PCBs) polychlorinated biphenyls, and polybrominated diphenyl ethers (PBDEs) was determined in blood samples from 70 subjects between 4 and 76 years old. The participants of the study were recruited in the neighborhood of a reclamation plant located in a rural area in Southern Germany. The median concentrations (95th percentiles in parentheses), expressed as WHO2005-TEQ (toxic equivalents), for PCDD/Fs and dl-PCBs were 4.5 (17.9)pgg(-1) l.w. and 2.6 (13.2)pgg(-1) l.w., respectively. The dl-PCBs contributed 40% of the total TEQ (median values), and the most abundant congener was PCB 156. Combined, the sum of the 6 non-dioxin-like PCBs had a median of 0.773µgL(-1) and a 95th percentile of 4.895µgL(-1). For the six tetra to hepta PBDE congeners, the median was 1.8ngg(-1) l.w. (95th percentile: 16.2ngg(-1) l.w.). None of our study subjects had a body burden that exceeded the biomonitoring equivalents for dioxins or PBDE congener 99 or the human biomonitoring values for ndl-PCBs. Likewise the study group did not exceed German reference values or values obtained in similar investigations. Overall, our study did not exhibit elevated internal exposures. The results also hint further decreasing tendencies for PCDD/Fs, PCBs, and PBDEs in Germany and demonstrates that people in the vicinity of a reclamation plant with no indication of an environmental contamination did not exhibit elevated internal exposures.

Effects of chain length, chlorination degree, and structure on the octanol-water partition coefficients of polychlorinated n-alkanes.

Log octanol-water partition coefficients (log Kow) of 40 synthesized polychlorinated n-alkanes (PCAs) with different chlorination degrees were determined using reversed-phase high performance liquid chromatography (RP-HPLC). In addition, log Kow values of a technical mixture namely Cereclor 63L as well as 15 individual in house synthesized C10, C11, and C12 chloroalkanes with known chlorine positions were estimated. Based on these results, the effects of chain length, chlorination degree, and structure were explored. The estimated log Kow values ranged from 4.10 (polychlorinated n-decanes with 50.2% chlorine content) to 11.34 (polychlorinated n-octacosanes with 54.8% chlorine content) for PCAs and from 3.82 (1,2,5,6,9,10-hexachlorodecane) to 7.75 (1,1,1,3,9,11,11,11-octachlorododecane) for the individual chloroalkanes studied. The results showed that log Kow value was influenced linearly at a given chlorine content by chain length, while a polynominal effect was observed in dependence on the chlorination degree of an alkane chain. Chlorine substitution pattern influenced markedly the log Kow value of chloroalkanes.