This paper describes an analytical procedure for free estrogens and their conjugates in domestic wastewater. The procedure demonstrated in this study is innovative in terms of levels of detection and quantification of the following substances: estrone (E1); 17beta-estradiol (E2); 17alpha-ethynylestradiol (EE2); estriol (E3); estrone-3-sulfate (E1-S); beta-estradiol 3-sulfate (E2-S); estriol 3-sulfate (E3-S); estrone beta-D-glucuronide (E1-G); beta-estradiol 17-(beta-D)-glucuronide (E2-G); estriol 3-(beta-D)-glucuronide (E3-G); beta-estradiol 3-sulfate 17-glucuronide (E2-SandG); and estradiol 3,17-disulfate (E2-diS). The detection limits of this method ranged from 0.1 to 1.4 ng/l. The recovery efficiencies of the estrogens in the analysis from influent and effluent of the secondary settling tank in a wastewater treatment plant (WWTP) were higher than 94% for the free estrogens, but were less than 50% for the conjugated estrogens. The field study using this method was conducted at twenty WWTPs in Japan. The median concentrations of the estrogens ranged from ND to as high as >100 ng/l. In the influent and secondary effluent samples, the concentrations of E1, E2 and E3 were the same levels as those previously reported. We found that the conjugated estrogens exist at higher concentrations in the influent and the secondary effluent than in the other studies, and that the concentrations of the conjugated estrogens were higher than those of the free estrogens.

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Laboratory evaluations were conducted to study the toxic responses of heavy metals such as copper and nickel of an autotrophic culture of strict nitrifiers (Nitrosomonas sp. and Nitrobacter sp.) in continuous flow stirred tank reactors (CSTR). One of the CSTRs was operated as a suspended growth (SG) system while the other was operated as an attached & suspended growth (A&SG) system. Nitrification inhibition in a SG and A&SG systems was investigated with the emphasis on the effect of shock loading of copper and nickel. As a result of the copper and nickel test, Nitrosomonas sp. was found to be equally or more sensitive than Nitrobacter sp. However, a higher influent nickel concentration of 50 mg/L was needed to cause a similar percent inhibition of ammonium oxidation than the copper concentration of 5 mg/L. A geochemical equilibrium speciation model, MINTEQA2/PRODEFA2, was used to compute the concentrations of various chemical species present in the wastewater for both systems. The high correlations of Cu(NH3)4+2 and Ni(NH3)4+2 with percent inhibition were found and it was thought that they were probably the species responsible for the inhibition of ammonia oxidation.

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A mineral medium for studying the growth of Nitrosomonas europaea was developed and examined. The medium was defined in terms of chemical speciation by using chemical equilibrium computer models. The medium significantly increased the metabolic activity of the organisms compared with previously developed media, yielding a specific growth rate as high as 3.0 day-' (generation time, 5.5 h). The specific growth rate was enhanced by increasing the inoculum and was linearly correlated with the inoculum-to-total-culture volume ratio on a semilog scale. A reproducible growth rate for N. europaea was obtained with this medium under controlled experimental conditions.

Many of the hazardous waste sites identified by U.S. EPA are contaminated with chlorinated organics such as perchloroethylene (PCE) and polychlorinated biphenyls (PCBs). Since these compounds are toxic to indigenous microorganisms, bioremediation is considered impractical at highly contaminated sites, and a chemical treatment method is often recommended. Fenton's reagent has recently drawn considerable attention because of its ability to decompose a variety of organic compounds. This study has been undertaken to examine the efficacy of Fenton's reagent to decompose PCE and PCBs adsorbed on sand. Results have shown that oxidation by Fenton's reagent can be an effective method to remediate PCE-and PCBs-contaminated soils. Over 90% of PCE was decomposed in 2 h, and over 70% of PCBs were degraded in 3 h. PCE followed the first-order decomposition kinetics with a constant value of 1.65/h, while the PCB degradation appeared to be zero-order with a constant value of 37.6 mg PCB/kg sand/hr at pH 3. Possible byproducts during the oxidation reaction were also examined.Tetrachloroethylene (perchloroethylene, PCE) has been widely used as a reagent for dry cleaning, metal degreasing, and as an industrial solvent. PCBs were extensively used (before 1976) in dielectric fluids, plasticizers, cutting oils, and other purposes throughout industries because of their chemical and thermal stability, low or nonflammability, and good electrical insulating properties. These properties are responsible for PCB's extreme persistence in the environment. Both PCE and PCBs are known to be