Life-cycle exposure of fathead minnows to a mixture of six common pharmaceuticals and triclosan.

Fathead minnows were exposed for a life cycle to environmentally relevant concentrations of a mixture of six common pharmaceuticals and one personal care product (nominal concentrations: 1,000, 300, 100, 30, or 10 ng/L). Mean measured concentrations of each chemical in the highest fish exposure aquaria were: naproxen 793 ng/L, gemfibrozil 662 ng/L, diclofenac 331 ng/L, ibuprophen 217 ng/L, triclosan 115 ng/L, salicylic acid 67 ng/L, and acetaminophen (chemical analysis inconclusive, nominal 1000 ng/L). Fish exposed for a life cycle even to the highest concentrations of the six pharmaceuticals and personal care product (PPCP) mixture showed no significant changes in growth and development compared to control. Length, weights, condition factors, liver weights, and gonad weights of PPCP-exposed fish were similar to water and solvent controls (0.000005% ethanol v/v). There were no marked effects of PPCP mixture exposure on external sex characteristics of the fish or on egg production. The only parameter that appeared to be affected was percent larval deformities in F1, which showed a significant increase in the 100- and 300-ng/L (nominal) PPCP mixture. Larvae from control fish had 4.7% (water controls) and 3.4% (solvent controls) deformities, compared to 9.3% in the 100-ng/L (nominal) PPCP mixture and 9.2% deformities in the 300-ng/L (nominal) PPCP mixture. Chronic exposure to environmentally relevant concentrations of seven PPCP most often detected in Canadian municipal wastewater effluents (MWWE) did not appear to affect fathead minnow survival, growth, or egg production, although it produced quantitative increases in deformities in the F1 generation.

Effect of a mixture of seven pharmaceuticals on Hyalella azteca over multiple generations.

A mixture of seven common pharmaceutical agents (acetaminophen, diclofenac, gemfibrozil, ibuprofen, naproxen, salicylic acid, and triclosan) was tested for its effects on the freshwater amphipod Hyalella azteca over three generations. The target concentration of each chemical (100ngl(-1)) was representative of the upper range observed for these substances in Canadian fresh waters, except in the immediate vicinity of effluent discharges. No statistically significant effects were observed on survival, mating, body size or reproduction. The sex ratio changed slightly to 17% more males. The seven pharmaceuticals tested do not appear to be substances of major concern for Hyalella in most Canadian fresh waters, but significant impacts might be observed in areas closer to effluent discharges.

Distribution of estrogens, 17beta-estradiol and estrone, in Canadian municipal wastewater treatment plants.

The distribution of female hormones, 17beta-estradiol and estrone, was determined in effluents of 18 selected municipal treatment plants across Canada. Replicate 24-h composite samples were collected from the influent and final effluent of each treatment plant, and the removal efficiency compared to the operational characteristics of the plants. In conventional activated sludge and lagoon treatment systems, the mean concentrations of 17beta-estradiol and estrone in influent were 15.6 ng/l (range 2.4-26 ng/l) and 49 ng/l (19-78 ng/l). In final effluents, the mean concentrations of both 17beta-estradiol and estrone were reduced to 1.8 ng/l (0.2-14.7 ng/l) and 17 ng/l (1-96 ng/l), respectively. 17beta-estradiol was removed effectively, >75% and as high as 98%, in most of the conventional mechanical treatment systems with secondary treatment. The removal of estrone was much more complex with removal varying from 98% to situations where the concentrations in the effluent were elevated above that detected in the influent. The estrogenicity, measured using a transfected estrogen receptor in yeast (YES) assay, was also variable, ranging from high removal to elevations of estrogenicity in final effluent. Although the apparent removals were not statistically correlated with either hydraulic (HRT) or solid (SRT) retention times, plants or lagoons with high SRT were very effective at reducing the levels of hormones. Well-operated plants that achieved nitrification also tended to have higher removal of hormones than those that did not nitrify. Laboratory aerobic reactor experiments confirmed the rapid removal of 17beta-estradiol, estrone, and estrogenicity when exposed to sewage slurries.