Evaluation of waterborne estrogenic activity at a land-based, water recirculation aquaculture facility using E-screen

Authors: Shappell, Nancy; GOOD, CHRISTOPHER - Freshwater Institute; Harper, Susan; DAVIDSON, JOHN - Freshwater Institute; HARRISON, COURTNEY - Freshwater Institute

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/2019
Publication Date: 11/3/2019
Citation: Shappell, N.W., Good, C.M., Harper, S.B., Davidson, J., Harrison, C.E. 2019. Evaluation of waterborne estrogenic activity at a land-based, water recirculation aquaculture facility using E-screen [abstract]. 40th Annual Mtg of North American Society of Environmental Toxicology and Chemistry. November 3 - 7, 2019. Toronto, Canada. Poster No. 354.

Interpretive Summary:

Technical Abstract: Land-based, closed-containment production of Atlantic salmon Salmo salar using recirculation aquaculture system (RAS) technologies could prove a viable avenue for aquaculture industry expansion, given the limited coastal locations worldwide that are suitable for raising this species in tradition sea cage systems. At present, certain hurdles remain regarding RAS Atlantic salmon production; these include early maturation, which can result in decreased product quality through reduction in normal flesh coloration. It is hypothesized that accumulating steroid hormones in RAS water can influence early maturation. We therefore sought to investigate waterborne estrogenic activity at a land-based RAS facility raising Atlantic salmon, utilizing the highly sensitive in vitro assay E-screen. Water samples were collected from replicated (n=3) RAS (treated with or without ozone, +O3 or - O3), as well as influent spring water and combined facility effluent water, over a 4-month sampling period. Samples were also collected from the facility spring pond, receiving both spring water and facility effluent, and a nearby duck pond (presumed positive control). E-screen results indicated that estrogenic activity of influent RAS water from +O3 or -O3 was never greater than 0.008 ng/L of estradiol equivalents (E2Eq), with 75% of intake samples either = solvent method blanks or below the limits of quantitation. Concentrations of all water samples collected were 10-fold lower than the predicted No Effect Concentration for E2 in fish (2 ng/L). While culture tank water from +O3 RAS tended to be lower in E2Eq than those from -O3 RAS, there was some inconsistency across all RAS culture tanks. On one sampling date the ozonated culture tanks had higher E2Eqs than two of the non-ozonated RAS tanks. Liquid chromatography, tandem mass spectrometric (LC-MSMS) analysis of samples from this date confirmed the presence of estrone in all RAS tank samples, with quantitation valid only in the three RAS with higher E2Eqs. Estradiol glucuronide was present in the same three RAS, and in spring and duck pond samples. Estrone concentrations were ~ 3 times higher in the duck pond than in the RAS tank waters. The extremely low concentrations of E2Eqs in tank waters indicate there would be no threat to aquatic life by release of tank effluents to environmental surface waters. While estrogenic activity of water from ozonated RAS tanks tended to be lower, ozonation treatment had no significant effect on Atlantic salmon early maturation, which was high in both +O3 or - O3 RAS. Further investigation is therefore required to assess the role of accumulating steroid hormones in RAS, alone and in combination with other important environmental variables, on the development of early sexual maturation in Atlantic salmon.