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Aromatic sensitizers and related compounds (SRCs) originating from thermal recording material as impurities in waste paper have been detected in aquatic environments near cities where the paper industry is flourishing. In the present study, the levels of exposure to such SRCs and the stable isotope ratios (δ13C and δ15N) in different fish species (Konosirus punctatus, Takifugu niphobles, and Tribolodon hakonensis) were analyzed. These fish species were collected from the vicinity of waste paper recycling plants in Japan. Eleven SRCs were identified in fish muscle at total concentration levels (ΣSRCs) of 64 to 818 ng/g wet weight (mean 181 ng/L wet wt). The dominant SRCs in the fish samples were 1,1-di(4-methylphenyl)ethane, 1,2-bis(3-methylphenoxy)ethane, and 1,4-dibenzyloxybenzene. Stable isotope ratios showed that, although three species feed on the same trophic level, K. punctatus and T. niphobles live in waters farther offshore than those in which T. hakonensis live. The contributions of various factors to the accumulation were also assessed. The lipid content (r2 = 0.512, p

The ability of some pulp mill effluents (PME) to act as reproductive and endocrine disrupters in fish is well documented in the literature. However, changes are not always consistent with regard to species, gender, hormones, or reproductive effects. In the present study, the presence of the first intersexed fish that, to our knowledge, has been found in a Canadian river exposed to PME, is reported. A field survey of the Wabigoon River near Dryden, Ontario, in the fall of 2000 found intersexed walleye (Sander vitreus vitreus) with significantly altered hormone levels and reduced gonad size. The Wabigoon River receives discharge from a bleached kraft pulp and paper mill and a municipal wastewater (MWW) plant. It also has historical sediment contamination (wood fiber mats) contributing to extended periods of low dissolved oxygen under low flow, drought conditions. A mesocosm-based partial life cycle test exposing fathead minnows (Pimephales promelas) to reference water, 20% effluent volume to river volume (v/v), 40% (v/v), or 60% (v/v) PME as well as a field survey of the walleye in the Wabigoon River were conducted. The only change in our mesocosm exposure was a decrease in testosterone in males with increasing effluent concentration and vitellogenin induction in males exposed to 60% (v/v) effluent. These results did not reflect the magnitude of endocrine disruption seen in the wild fish survey. Several hypotheses that may explain these discrepancies are proposed. Specifically, evidence is offered from published studies indicating that either hypoxia or MWW, alone or in combination with PME, may explain the discrepancy between our field experiment and the wild fish survey. The present study illustrates the complexities of multistressor receiving environments and the need for the development of cumulative effects assessment approaches. Environ. Toxicol. Chem. 2010;29:952–965. © 2010 SETAC

The Canadian environmental effects monitoring (EEM) program is a regulated, cyclical, industry-funded program designed to determine whether receiving water impacts exist when a mill is in compliance with its discharge limits. The results from three cycles of the fish monitoring program (1992 to 2004) are available from over 200 surveys of fish compared between sites located upstream and downstream of pulp and paper mill effluent outfalls. Previous meta-analyses have shown a national average response pattern across cycles characterized by an increase in endpoints measuring energy storage and growth and a decrease in a reproductive endpoint, consistent with a response of nutrient enrichment in combination with some form of metabolic disruption. Although the national average pattern of effects was temporally consistent, there was some variability in the magnitude of effects among cycles. Questions were raised as to whether the intercycle variability was due to changes in effluent quality or due, at least in part, to other factors. The present study compares responses over the first three cycles, and shows that the choice of sentinel species is likely to be a major contributing factor to the variability in observed effects. Subset analyses using studies from mills that used the same sentinel species across cycles reveal fairly uniform responses and little evidence of significant improvements in overall fish health from cycles one to three. However, a meta-analysis using 1991 data collected from 10 mills before the implementation of the EEM program and data from the same mills collected during cycles one to three of the program reveal significantly reduced effects on relative liver weight and potential improvements in other endpoints. Environ. Toxicol. Chem. 2010;29:440–452. © 2009 SETAC