Helen Björnfoth

Adipose tissue concentrations of persistent organic pollutants and the risk of prostate cancer.

Objective: We sought to study the concentrations of certain persistent organic pollutants with endocrine-disrupting properties in cases with prostate cancer and controls with benign prostate hyperplasia. Methods: Adipose tissue was obtained from 58 cases and 20 controls. Results: The median concentration among controls was used as cut-off in the statistical analysis. In the total material, a greater-than median concentration of PCB congener 153 yielded an odds ratio (OR) of 3.15 and 95% confidence interval (CI) of 1.04–9.54 and one chlordane type, trans-chlordane, yielded OR 3.49 (95% CI = 1.08–11.2). In the group of case subjects with PSA levels greater than the median level of 16.5 ng/mL, PCB 153 was OR 30.3 (95% CI = 3.24–284), hexachlorobenzene OR = 9.84 (95% CI = 1.99–48.5), trans-chlordane OR = 11.0 (95% CI = 1.87–64.9), and the chlordane-type MC6 OR = 7.58 (95% CI = 1.65–34.9). The grouping of PCBs according to structural and biological activity was found to produce significantly increased risks for enzyme and phenobarbital-inducing PCBs and lower chlorinated PCBs in the case group with PSA levels greater than 16.5 ng/mL. Conclusions: These chemicals might be of etiologic significance but need to be further investigated. The biological relevance of the arbitrary cut-off point of PSA is unclear.

Fractionation and Determination of Ah Receptor (AhR) Agonists in Organic Waste After Anaerobic Biodegradation and in Batch Experiments with PCB and decaBDE (8 pp)

Goals, Scope and BackgroundAnaerobic digestion of organic household waste can lead to an increase in dioxin-like content, as determined by dioxin-specific bioassays. This may be a result of bioactivation of Ah receptor (AhR) agonists into more potent congeners. Work towards identifying the contributing compound groups is important in order to understand the mechanisms and to assess the relevance behind this increase in dioxin-like toxicity, since the residue can be used as a soil fertilising agent. The aim with the present work was to identify compound groups with AhR agonistic properties that caused the previously reported increase in dioxin-like activity after anaerobic biodegradationMethodsFirstly, chemical fractionation combined with dioxin bioassay testing was used to find bioactive classes of compounds. Secondly, batch digestion experiments with an externally added polychlorinated biphenyl (PCB) mixture (Clophen A50) and with decabrominated diphenyl ether (decaBDE), respectively, were studied as a possible process for transformation of precursors into more potent, dioxin-like compounds. Mesophilic (37ºC) and thermophilic (55ºC) anaerobic digestion were studied. Two different dioxin-specific bioassays were used to analyse AhR agonists in the biodegraded material, the CELCAD and the DR-CALUX. Results and DiscussionAhR agonist activity was detected in both di- and polyaromatic fractions of digestate extracts, which indicated that a diverse mixture of compounds contributed to the bioassay responses. No quantifiable activities were induced by the monoaromatic fractions. Further fractionation based on planarity revealed higher concentrations of AhR agonists than what was detected after the first fractionation, probably due to non-additive biological interactions of compounds in the extract that were removed in the second fractionation. These results showed significant activity in the non-planar diaromatic fractions and in the co-planar fractions of both diaromates and polyaromates. In the batch experiment with externally added PCB, an increase in dioxin-like activity was seen after 21 days of digestion at mesophilic conditions. After completed digestion, the content of AhR agonists was equal to the start concentration. PCB analysis with GC-MS indicated that dehalogenation of PCBs occurred in the digestors. The batch experiment with decaBDE showed no significant changes in TEQ-concentrations over time.ConclusionsThe results show that the previously reported increase of AhR agonists during mesophilic anaerobic digestion is probably due to an accumulation of several different groups of AhR agonists, both diaromatic and polyaromatic, and both co-planar and non-planar. Batch experiments with externally added PCBs and decaBDE, respectively, did not result in any accumulation of AhR agonist activity after completed digestion, even though chemical analysis indicate a dechlorination of PCBs. Complex, unfractionated extracts were difficult to test using the bioassay approach. Removal of AhR antagonists or otherwise interacting compounds during fractionation may yield bio-TEQ values that are much higher than in the original extract.Recommendations and PerspectiveOur results indicate that the environmental risk that AhR agonists may pose concerning large-scale anaerobic digestion of organic household waste probably depends on the efficiency of the digester and the sludge residence time. In order to obtain reliable results with the bioassays, an extensive cleanup and fractionation procedure is necessary. Without clean up and fractionation, there is a risk for false negatives and misleading conclusions. DR-CALUX and CELCAD were both suitable for these kinds of studies, provided that suitable fractionation methods are used.

Increased Concentrations of Certain Persistent Organic Pollutants in Subjects with Self-Reported Electromagnetic Hypersensitivity—A Pilot Study

Electromagnetic hypersensitivity (EHS) is used for a variety of subjective symptoms related to exposure to electromagnetic fields (EMF). The aim of this pilot study was to analyze the concentrations of certain persistent organic pollutants (POPs) in subjects with self-reported EHS. In total, 13 EHS subjects and 21 controls were included, all female. The concentration of several POPs was higher in EHS subjects than in controls. Lower concentrations were found for hexachlorobenzene and two types of chlordanes. The only significantly increased odds ratios (ORs) were found for polybrominated diphenyl ether (PBDE) #47 yielding OR=11.7, 95% confidence interval (CI)=1.45–94.7 and the chlordane metabolite MC6 with OR=11.2, 95% CI=1.18–106. The results were based on low numbers and must be interpreted with caution. This hypothesis generating study indicates the necessity of a larger investigation on this issue.