Spatial and seasonal occurrence of pesticides and environmental contaminants in fish tissues influenced by snowmelt and municipal effluent discharge

Authors: Sapozhnikova, Yelena; SALAMOVA, AMINA - INDIANA UNIVERSITY; HADDAD, SAMUEL - BAYLOR UNIVERSITY; BURKET, S - BAYLOR UNIVERSITY; LUERS, MICHAEL - GREAT BASIN LANDSCAPE CONSERVATION COOPERATIVE; BROOKS, BRYAN - BAYLOR UNIVERSITY

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2020
Publication Date: 6/15/2020
Citation: Sapozhnikova, Y.V., Salamova, A., Haddad, S., Burket, S.R., Luers, M., Brooks, B. 2020. Spatial and seasonal occurrence of pesticides and environmental contaminants in fish tissues influenced by snowmelt and municipal effluent discharge. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2020.140222.
DOI: https://doi.org/10.1016/j.scitotenv.2020.140222

Interpretive Summary: In this study, we examined occurrence of pesticides and environmental contaminants in two fish species - brown trout (Salmo trutta) and mottled sculpin (Cottus bairdii) collected from East Canyon Creek, Utah, USA. The creek is a unique ecosystem influenced by snowmelt in spring and municipal effluent discharge in summer-fall. Fish tissues were collected in May, August, September and October from four sampling sites - one reference site upstream, and three sites at incremental distances downstream of the effluent discharge to examine spatial and seasonal accumulation of contaminants. The fish tissues were analyzed for 218 lipophilic contaminants, including pesticides and their metabolites, and environmental contaminants. Out of 218 contaminants, 11 were measured in mottled sculpin, and 18 were measured in brown trout tissues, all at low ng/g levels. No differences in levels of contaminants were observed between seasons. Spatial differences were observed for banned flame retardants - polybrominated diphenyl ethers (PBDEs) with lowest levels at the reference upstream site and highest levels downstream close to the effluent discharge.

Technical Abstract: The goal of this study was to examine spatial and seasonal trends in the levels of pesticides and environmental contaminants in brown trout (Salmo trutta) and mottled sculpin (Cottus bairdii) fish tissues influenced by snowmelt and municipal effluent discharge in East Canyon Creek, Utah, USA, an effluent-dominated stream during summer months. Fish tissues were collected from four sampling sites, including one reference site upstream, and three sites at incremental distances downstream of the effluent discharge. The samples were analyzed for 218 lipophilic contaminants, including pesticides and their metabolites, and other environmental contaminants: polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyls (PBDEs) and other flame retardants by low pressure GC-MS/MS. Some PAHs, pesticides and metabolites, PCBs, PBDEs and flame retardants were measured in mottled sculpin (11 analytes) and brown trout (18 analytes). Hexachlorobenzene (HCB), p,p’-DDE, PBDE-47 and triphenyl phosphate (TPP) were the most frequently detected contaminants in mottled sculpin and brown trout tissues, while PBDE-47 and p,p’-DDE were measured at highest concentrations, reaching up to 73 and 19 ng/g wet weight, respectively. A spatial pattern was observed for PBDE congeners, where lowest concentrations were measured in fish tissues from the reference sites, and highest concentrations were measured in fish collected downstream of the effluent discharge, indicating that municipal effluent discharge contributes to the elevated PBDE levels in fish residing in this effluent-dominated stream. Screening level consumption risks were calculated following EPA methods.