Endocrine disrupting chemicals (EDCs) such as natural and synthetic hormones or industrial chemicals can adversely affect the endocrine system at very low concentrations. As such substances can be present in raw water used for drinking-water production, they potentially pose a health risk to humans. In this study laboratory tests were performed to determine removal efficiencies of selected oxidative drinking water treatment processes, namely ozonation (1.4 mg/l O3) and chlorination, using sodium hypochlorite (0.5 mg/l NaClO) and chlorine dioxide (0.4-0.6 mg/l ClO2) under conditions applied in technical plants. 500-300,000 ng/l of bisphenol A (BPA), 4-nonylphenol (4-NP) and 4-nonylphenol-n-ethoxylates (NPnEO) were selected for investigations and measured by HPLC/FLD and HPLC/MS. To investigate possible oxidation by-products, adsorbable organic halogens (AOX) were determined and estrogenic activities were assessed with the help of an estrogen receptor binding assay (YES). Ozonation and chlorination with ClO2 removed both 4-NP and BPA below detection limits, corresponding with AOX and estrogenic activity. Concerning NPnEO ozonation removed NP1EO and NP2EO up to 28% and 30%, respectively, whereas ClO2 showed high removal efficiencies, eliminating >94% and 92%, respectively. NaCIO removed 4-NP and BPA below detection limits, but estrogenic activities increased and AOX could be measured. NP1EO and NP2EO were only marginally reduced corresponding to the slight decrease of estrogenic potential.

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Subacute levels ( 5 pg per day) of 14C-labeled dieldrin or photodieldrin were administered to young adult rats of both sexes for as long as 12 weeks. Photodieldrin was given both orally and intraperitoneally ; dieldrin was given by stomach tube only. Urinary, fecal, and total excretion patterns as well as tissue distribution and storage of 'T-labeled residues were determined. From 59.2 to 64.7z of the 14C-activity administered as photodieldrin was excreted in the urine and feces of male rats and 45.9 to 49.0 z was found in the excreta of females. A total of 63.6z of the 14C-activity from dieldrin was excreted by male rats and only 37.0z by females. Analysis of various tissues showed that from 3 to 10 times more 14C-activity was retained by females as compared to males after photodieldrin, regardless of the route of administration. A similar sex difference in tissue levels was found after administration of dieldrin. Adipose tissue was the principal storage site of both dieldrin and photodieldrin in female rats and of dieldrin in male rats. Extremely high levels of 14C-activity were detected in the kidneys of male rats receiving photodieldrin. D ieldrin (1,2,3,4,10,10-hexachloro-exo-6,7-epoxy-l,4,4a, 5,6,7,8,8a -octahydro -1,4 -endo, exo -5,8 -dimethanonaphthalene), when present as deposits o n grass and subjected to sunlight, undergoes photodecomposition (Roburn, 1963). Acute toxicity studies by Rosen and Sutherland (1967) and by Brown er a/. (1967) have suggested that the photoconversion product of dieldrin (photodieldrin) is more toxic to certain mammalian species than the parent compound. Because of these findings, it became of interest to study excretion and storage patterns after administration of subacute levels of photodieldrin to rats of both sexes and to compare these patterns with those found after administration of dieldrin under the same conditions. Since the desired dose levels were low, it was advantageous to use radiolabeled compounds. METHODS AND MATERIALSReagents and Apparatus. l?C-photodieldrin was prepared by ultraviolet irradiation of IT-dieldrin (NuclearChicago Corp.) using a method recently described by Benson (1969). Both compounds were judged to be essentially free of interfering substances by gas-liquid and thin-layer chromatographic techniques. The specific activity of the I4C-dieldrin used was 5.3 mCi per mmole, and the 14CC-photodieldrin was diluted with pure unlabeled photodieldrin to a specific activity of 4.3 mCi per mmole in order to provide enough material to complete the studies as planned. Both compounds were dissolved in acetone and stored at -20" C in the dark. At the time of administration, the acetone was evaporated and the compounds were redissolved in corn oil.All radioactivity measurements were made with a Packard Model 3375 liquid scintillation spectrometer, using a scintillation phosphor prepared by dissolving 4.0 g of 2,5-diphenyloxazole (PPO, Packard Instrument Co.) and 0.100 g of 1,4-bis-[2-(4-methyl-5-phenyloxolyl)] benzene (DMPOPOP, Packard Instrument Co.) in a mi...

Osborne-Mendel rats were maintained on diets containing 100 p.p.m. of p,p'-DDT. The microflora of the gastrointestinal tract were not significantly altered by this diet. Pure cultures of bacteria, typically found in the gastrointestinal tract, were grown in the presence of DDT. Most of the genera studied degraded the pesticide to DDD; the ex-ception was the Gram-positive cocci. The negative findings for those organisms may be due to intracellular binding of DDT and its metabolites. These data provide evidence that DDD in the feces of rats fed DDT may largely be the product of microbial rather than mammalian metabolism.