Model ecosystem evaluation of the environmental impacts of the veterinary drugs phenothiazine, sulfamethazine, clopidol, and diethylstilbestrol.

Abstract

Four veterinary drugs of dissimilar chemical structure were evaluated for environmental stability and penchant for bioaccumulation. The techniques used were I1) a model aquatic ecosystem (3 days) and (2) a model feedlpt ecosystem 133 days I in which the drugs were introduced via the excreta of chicks or mice. The model feedlot ecosystem was supported by metabolism cage studies to determine the'amount and the form of the drug excreted by the chicks or mice. Considerable quantities of all,the drugs were excreted intact or as environmentally short-lived conjugates.Diethylstilbestrol (DES) and Clopidol were the most persistent molecules, but only DES bioaccumulated to any 4ppreciable degree. Phenothiazine was very biodegradable; sulfamethazine was' relatively biodegradable and only accumulated in the organisms to very low levels.Data from the aquatic model ecosystem demonstrated a good correlation between the partitibn coefficients of the drugs and their accumulation in the fish.

Environmental fate of five radio-labeled coal conversion by-products evaluated in a laboratory model ecosystem

“…The unextractable radioactivity represented 88.6% of the total radioactivity in alga, 19.9% in snail, 47.9o in mosquito, and 61.9% in fish. The overall environmental behavior of dibenzothiophene was very similar to that observed in comparable studies with '4C-phenothiazine (23 (25) and these lead to ready conjugation and excretion. Benzo[a]pyrene is also highly photodegradable.…”

Fate and bioavailability of sulfamethazine in freshwater ecosystems

“…Previous soil fate studies have indicated that SMZ is not strongly sorbed to soils and is likely to be highly mobile in the aqueous portion of runoff, thus being likely to reach surface water bodies, e.g. small ponds (5,(10)(11)(12). Though its fate has been extensively examined in soil, SMZ fate in surface water, and sediment in particular, has not been extensively studied.…”

Human Pharmaceuticals in the Aquatic Environment: A Review of Recent Toxicological Studies and Considerations for Toxicity Testing

“…The prototypical estrogen compound diethylstilbestrol (DES) has been well studied, in that four studies have been conducted on six different species. Coats et al ( 1976 ) investigated the acute toxicity of DES on algae, invertebrates, and fi sh, identifying invertebrates ( Culex pipiens and D. magna ) as the most sensitive group (48-h LC 50 = 4 mg/L). Baldwin et al ( 1995 ) and Zou and Fingerman ( 1997 ) reported D. magna to be even more sensitive than previously reported to DES exposure, based on 48-h LC 50 values ranging from 1.1 to 1.2 mg/L; however, EE2 is signifi cantly more acutely toxic than DES to algae (EC 50 = 0.84 mg/L) and fi sh (96-h EC 50 = 1.6 mg/L) (Kopf 1995 ;Schweinfurth et al 1996 ) .…”