Analytical and Biological Characterization of Halogenated Gemfibrozil Produced through Chlorination of Wastewater

The cholesterol-lowering pharmaceutical gemfibrozil is a relevant environmental contaminant because of its frequency of detection in U.S. wastewaters at concentrations which have been shown to disrupt endocrine function in aquatic species. The treatment of gemfibrozil solutions with sodium hypochlorite yielded a 4′-chlorinated gemfibrozil analog (chlorogemfibrozil). In the presence of bromide ion, as is often encountered in municipal wastewater, hypobromous acid generated through a halogen exchange reaction produced an additional 4′-brominated gemfibrozil product (bromogemfibrozil). Standards of chloro- and bromogemfibrozil were synthesized, isolated and characterized using mass spectrometry and NMR spectroscopy. Mass spectrometry was used to follow the in situ halogenation reaction of gemfibrozil in deionized water and wastewater matrices, and to measure levels of gemfibrozil (254 ± 20 ng/L), chlorogemfibrozil (166 ± 121 ng/L), and bromogemfibrozil (50 ± 11 ng/L) in advanced primary wastewater treatment effluent treated by chlorination. Chlorogemfibrozil demonstrated a significant (<i>p</i> < 0.05) reduction in the levels of 11-ketotestosterone at 55.1 μg/L and bromogemfibrozil demonstrated a significant (<i>p</i> < 0.05) reduction in the levels of testosterone at 58.8 μg/L in vivo in Japanese medaka in a 21 day exposure. These results indicated that aqueous exposure to halogenated degradates of gemfibrozil enhanced the antiandrogenicity of the parent compound in a model fish species, demonstrating that chlorination may increase the toxicity of pharmaceutically active compounds in surface water

Reconstitution Studies of Pesticides and Surfactants Exploring the Cause of Estrogenic Activity Observed in Surface Waters of the San Francisco Bay Delta

To evaluate the potential role of endocrine disruption in the decline of pelagic fishes in the San Francisco Bay Delta of California, various surface water samples were collected, extracted, and found to elicit estrogenic activity in laboratory fish. Chemical analysis of the estrogenic samples indicated 2 pesticides (bifenthrin, diuron), 2 alkyphenols (AP), and mixtures of 2 types of alkyphenol polyethoxylates (APEOs). Evaluation of estrogenic activity was further characterized by in vitro bioassays using rainbow trout hepatocytes (<i>Oncorhynchus mykiss</i>) and in vivo studies with Japanese medaka (<i>Oryzias latipes</i>). In the in vitro bioassays, hepatocytes exposed to the pesticides alone or in combination with the AP/APEO mixtures at concentrations observed in surface waters failed to show estrogenic activity (induction of vitelloginin mRNA). In the in vivo bioassays, medaka exposed to individual pesticides or to AP/APEO alone did not have elevated VTG at ambient concentrations. However, when the pesticides were combined with AP/APEOs in the 7-day exposure a significant increase in VTG was observed. Exposure to a 5-fold higher concentration of the AP/APEO mixture alone also significantly induced VTG. In contrast to earlier studies with permethrin, biotransformation of bifenthrin to estrogenic metabolites was not observed in medaka liver microsomes and cytochrome P450 was not induced with AP/APEO treatment. These results showed that mixtures of pesticides with significantly different modes of action and AP/APEOs at environmentally relevant concentrations may be associated with estrogenic activity measured in water extracts and feral fish that have been shown to be in population decline in the San Francisco Bay Delta

NADPH-dependent clearance and transformation of 5ESL to 5ESLO in liver microsomes from four species of butterflyfish and recombinant human CYP3A4.

<p>Different letters indicate significant (P ≤ 0.05) differences between species* indicated signifcnat differences between control and pretreated <i>C</i>. <i>unimaculatus</i> (P ≤ 0.05) (N = 6–8).</p

Effects of dietary exposure to 5ESL on the hepatic content of CYP2M1-like protein (A) and catalytic activity (B) of and CYP2 in four species of butterflyfish.

<p>Different letters indicate significant (P ≤ 0.05) differences between untreated and treated fish (N = 6–8).</p

Effects of dietary exposure to <i>S</i>.<i>maxima</i> tissue homogenate on the hepatic content CYP2K1-like and CYP2M1-like (A, B) and catalytic activity (C) of and CYP2 in four species of butterflyfish.

<p>Different letters indicate significant (P ≤ 0.05) differences between untreated and treated fish (N = 6–8).</p

The percentage survival of butterflyfish after a 7 day oral exposure to high dose (3.0mg/kg), or low dose (1.0mg/kg) of 5ESL.

<p>Each value represents the total survival of 6–8 individuals.</p

Structures of 5ESL (A) of <i>S</i>. <i>maxima</i> and 5ESL 15,16 epoxide (5ESLO) (B).

<p>Structures of 5ESL (A) of <i>S</i>. <i>maxima</i> and 5ESL 15,16 epoxide (5ESLO) (B).</p

Effects of dietary exposure to <i>S</i>.<i>maxima</i> tissue homogenate on the hepatic content (A) and catalytic activity (B, C) of and CYP3A in four species of butterflyfish.

<p>Different letters indicate significant (P ≤ 0.05) differences between untreated and treated fish (N = 6–8).</p