Accumulation of ligands for aryl hydrocarbon and sex steroid receptors in fish exposed to treated effluent from a bleached sulfite/groundwood pulp and paper mill

Abstract

The accumulation of ligands for the aryl hydrocarbon receptor (AhR) and fish sex steroid receptors was investigated using two separate controlled fish exposures to final effluent from a bleached sulfite/groundwood mill in New Brunswick, Canada. In the first experiment, hepatic tissue extracts from exposed fish were fractionated according to lipophilicity. Fractions with different octanol-water (Kow) partition coefficients were tested for the presence of bioavailable chemicals that function as ligands for the AhR in H4IIE cells, rainbow trout hepatic estrogen receptors (ER), goldfish testicular androgen receptors (AR), and goldfish sex steroid binding protein (SSBP). Fish accumulated ligands for each receptor after 4-d exposure to effluent. Single fractions contained ligands for the AhR and the ER, while multiple fractions competed for the AR and SSBP. Fish also accumulated ligands for the AhR and SSBP from Saint John River dilution water, indicating upstream sources of bioactive substances. Semipermeable-membrane devices deployed concurrently with fish accumulated ligands from effluent for all receptors except the ER. In the second experiment, accumulated ligands were evaluated after exposure of fish to effluent for two different durations and following a depuration period. Hepatic mixed function oxygenase activity and whole-liver hormonal activity, measured as binding to SSBP, returned to background following 6 d depuration and were reduced but still significant after 12-d exposure to effluent. Whole-liver extract affinities for the AR were maintained after extended exposure and depuration, indicating the potential for AR ligands to bioaccumulate. The accumulation of AhR ligands and ligands for sex steroid receptors provides a mechanistic linkage to effects on growth, development, and performance of fish exposed to effluent from this and other mills.

Northern Rivers Ecosystem Initiative: Distribution and Effects of Contaminants

“…SPMDs deployed in effluent accumulated ligands for the fish AR, relative to the reference site. This pattern was consistent with results obtained for SPMDs deployed at other sites where the androgenic response was the strongest response observed (Hewitt et al, 2003). Wood chip extracts from the Grande Prairie mill were active in the assays tested with hexane extracts having the highest potencies .…”

“…SPMDs were deployed in the Wapiti River for 6 d at the Pipestone Creek reference site and in the foam pond at the pulp mill prior to the effluent entering the river. After retrieval, SPMDs were dialyzed into hexane (Hewitt et al, 2003) and dialyzed extracts were purified and solvent exchanged into methanol for incubations with fish sex steroid receptors.…”

Identification of Metabolites of Trenbolone Acetate in Androgenic Runoff from a Beef Feedlot

“…Although most early work focused on changes in the HPG axis caused by chemicals that bind to and activate estrogen receptors, recent studies have highlighted the variety of contaminants that can affect HPG function through interactions with the androgen receptor. For example, investigations of pulp and paper mill effluents from different locations in North America as well as an examination of a beef feedlot discharge from one site (Nebraska), have associated morphological alterations in fish collected from the field with in vitro androgenic activity in water samples from the affected sites (Hewitt et al 2003; Jenkins et al 2001; Orlando et al 2004; Parks et al 2001). Partly because of sample complexity, chemicals responsible for androgenic activity in pulp and paper mill effluents have not been identified successfully (Durhan et al 2002; Hewitt et al 2003).…”

“…For example, investigations of pulp and paper mill effluents from different locations in North America as well as an examination of a beef feedlot discharge from one site (Nebraska), have associated morphological alterations in fish collected from the field with in vitro androgenic activity in water samples from the affected sites (Hewitt et al 2003; Jenkins et al 2001; Orlando et al 2004; Parks et al 2001). Partly because of sample complexity, chemicals responsible for androgenic activity in pulp and paper mill effluents have not been identified successfully (Durhan et al 2002; Hewitt et al 2003). Similarly, little is known concerning the identity of chemicals that might be responsible for androgenic activity in feedlot discharges; however, with these types of samples, insights may be gained through consideration of chemicals used for livestock production.…”

Utilizing Molecular Technologies for Bioindicator Research

“…Some water treatment facilities do not include tertiary treatments to remove natural and synthetic estrogens such as 17-β estradiol (E 2 ) or ethinylestradiol (EE 2 ) (Desbrow et al 1996), or nonionic surfactants such as nonylphenol and octylphenol (Dierickx 1985;Sun et al 1998;Pickford et al 2003). Other sources of hormone contamination are the animal feeding operations that release wastewater contaminated with trenbolone as well as animal hormones (Durhan et al 2002;Orlando et al 2004) and pulp and paper mills ( Durhan et al 2002;Hewitt et al 2003). Plasticizers are also finding their way into the water and sediments, including phthalate esters (Walsh and Bahner 1980;Jobling et al 1996;Harris et al 1997;Meek et al 1997) and bisphenol A (Fry 1995;Kitamura et al 2005), and there is still concern about pesticides such as DDT and its metabolites (Kelce et al 1995), endosulfan (Klotz et al 1996), and methoxychlor, a DDT analog (Nimrod and Benson 1998;Versonnen et al 2004;Magliulo et al 2002).…”