Changes in Growth, Secondary Sex Characteristics, and Reproduction of Fathead Minnows Exposed for a Life Cycle to Bleached Sulfite Mill Effluent

Although multiple reproductive tests have been developed in small-bodied fish to determine the effects of endocrine-disrupting substances, few direct comparisons have been made among the available tests. Side-by-side reproductive tests with mummichog (Fundulus heteroclitus) and fathead minnow (FHM; Pimephales promelas) were conducted with 0, 3, 10, and 30% effluent from a bleached kraft pulp mill in Saint John, New Brunswick, Canada. Egg production was significantly increased in mummichog exposed to 3% combined mill effluent, but no difference was observed in FHM. No differences were found in whole-body testosterone or estradiol levels in mummichog, and whole-body 11-ketotestosterone levels in males were increased in 3% exposed fish compared to those in 10% effluent. Male FHM exposed to 30% effluent had increased whole-body testosterone levels, and female FHM in 30% effluent had decreased testosterone. No differences in estradiol or 11-ketotestosterone were observed in FHM. Relatively limited response occurred in other endpoints. A comparison of the results of the present study to other published studies suggests that current reproductive bioassays are only sensitive for detecting magnitudes of change of greater than 50% and that differences exist in the sensitivities of fish. Future research should address methods of reducing variability within test populations and focus on understanding the comparative responses among species commonly used for endocrine-disrupting substance testing.

Section: Discussionmentioning

confidence: 99%

Detectable effect size and bioassay power of mummichog (Fundulus heteroclitus) and fathead minnow (Pimephales promelas) adult reproductive tests

Melvin

Munkittrick

Bosker

et al. 2009

“…Hewitt, Environment Canada, Burlington, ON, unpublished data) shows the presence of compounds with estrogenic activity in screenings of the final treated effluent from this mill. Development of ovipositors and feminization of mature male fish has been shown to be a sensitive indicator of estrogenic effects in FHM full life‐cycle tests [28]. Development of ovipositors in mature male fish after exposure to bleached sulfite effluent also has been reported by Parrott and Wood [14], in which 18% of males exposed to 3.2% (v/v) effluent, 25% exposed to 10% (v/v) effluent, and 47% exposed to 32% (v/v) effluent developed ovipositors.…”

Section: Discussionmentioning

confidence: 99%

Use of paired fathead minnow (Pimephales promelas) reproductive test. Part 1: Assessing biological effects of final bleached kraft pulp mill effluent using a mobile bioassay trailer system

Rickwood¹,

Dubé²,

Hewitt³

et al. 2006

Self Cite

Reproductive effects have been recorded in wild fish in waters receiving pulp mill effluent (PME) since the mid to late 1980s. Laboratory assays with fathead minnow (FHM; Pimephales promelas) have been developed to better understand fish responses to PME. However, observations from laboratory studies have been variable, making it difficult to establish cause/effect relationships. A lack of environmental relevance in these laboratory studies may have contributed to the variability observed. The objectives of the present study were, first, to determine the effects of bleached kraft PME (BKME) on FHM under environmentally realistic conditions (i.e., ambient water and effluent quality) and, second, to determine the suitability of pair-breeding FHM to better link BKME-induced changes in indicators at the biochemical, individual, and population levels. A mobile bioassay trailer was situated on-site at a bleached kraft mill for 60 d, allowing supply of both ambient water (Lake Superior, Canada) and final BKME. The reproductive output of FHM was initially assessed for 21 d to obtain baseline data pre-exposure. At the end of the pre-exposure period, selected breeding pairs were exposed to final BKME (100% v/v and 1% v/v) for 21 d. Results demonstrated a stimulatory response pattern at 1% BKME (e.g., increased egg production) compared to control. In the 100% treatment, spawning events were reduced and fewer eggs were produced during the first two weeks of exposure. Exposure to 100% (v/v) BKME also resulted in ovipositor development in males and development of male secondary sex characteristics in females. Obtaining pre-exposure data and use of pair-breeding FHM in this assay gave a sensitive indication of effluent effects and allowed accurate comparisons of endpoints to be made.

“…This estrogenic response differs from the results in the Northern Hemisphere. Worldwide, the principal response in sites downstream of pulp mill discharge has been a reduction in gonad size, as has been seen in Canada [7,[33][34][35][36][37][38][39], the United States [40][41][42], Sweden [43], Finland [44], and New Zealand [45], where the possible causes are a reduction in the fish's steroid production capacity [46][47][48]. The alterations we observed at the reproductive level in individuals downstream of the discharge could be responsible for the differences in the size structure of the populations of both species, in which there is a temporal tendency toward a loss of smaller sizes.…”

Section: Discussionmentioning

confidence: 99%

Health status of native fish (Percilia gillissi and Trichomycterus areolatus) downstream of the discharge of effluent from a tertiary‐treated elemental chlorine‐free pulp mill in Chile

Chiang

McMaster

Urrutia

et al. 2011

Few data exist on the possible effects of pulp and paper effluent discharge on native fish populations in the Southern Hemisphere, relative to the research done in the Northern Hemisphere. The present research examined two native fish species (Trichomycterus areolatus and Percilia gillissi) for effects at both the molecular and individual level due to the discharge of effluent from a tertiary treated elemental chlorine-free pulp mill into a fluvial system in Central Chile over three seasons (February 2007, October 2007, January 2008). Different responses were observed between species and between sexes. There was an increase in the production of gonadal 17β-estradiol in the females of both species but a drop in 11-ketotestosterone production in P. gillissi males. Female gonadal size was increased, especially during the summer period, with corresponding increases the frequency of advanced oocyte development, and in the oocyte diameter in both species. Hepatic ethoxyresorufin-O-deethylase (EROD) activity was elevated for both species downstream of the discharge point, although overall it was higher in P. gillissi than T. areolatus. Decreases in the frequency of smaller-sized fish for both species, as well as a drop in the size of the adults downstream of the discharge point, were observed. The present study is the first evidence of endocrine disruption in native freshwater fish associated with modern pulp mills in South America. This study establishes possible links in the reproductive alterations observed at the subindividual and individual levels that could explain the changes observed at the population level.