Biological Activity in U.S. Food Processing Plant Effluent

Commercial food, beverage, and feedstock processing facilities produce wastewater with complex mixtures that are a probable source of bioactive contaminants. However, current monitoring of these wastewaters is primarily focused on basic constituents including pH, dissolved oxygen, and suspended solids. Therefore we measured organic compound (580 Phase I and 700 Phase II) concentrations  and biological activity in a two-phase study of wastewater effluent from 23 food processing facilities accross the United States. Samples were assessed for estrogenic, androgenic, glucocorticoid, and peroxisome proliferator-activated (PPAR; α and γ) receptor activity and for activation of 24 additional nuclear receptors and 52 transcription factor signatures using the multi-endpoint Attagene Trans-FACTORIALTM and Cis-FACTORIALTM assays, respectively. Effluent samples from each site (23/23) contained estrogenic activity (0.05 – 1.62; median: 0.26 ng E2Eq/L) and 10/23 contained estrogenic activity levels at which adverse effects may occur in aquatic species after chronic exposure. Androgenic activity was detected in 9/23 (0.19 – 8.41; median: 0.32 ng DHTEq/L) but no glucocorticoid or PPAR α/γ activity was detected in any sample above method detection limits (MDL). Attagene analysis corroborated single endpoint bioassay results indicating estrogenic activity in a variety of effluent types. To further characterize environmental exposures in Phase II, effluent, along with stream water up and downstream from the outfall, bed sediment, and aquatic organisms were collected from a subset of Phase I sampling sites (7/23). Samples up and/or downstream from an ethyl alcohol manufacturing and soybean/oilseed processing facility produced estrogenic activity comparable to effluent concentrations. Samples downstream from a non-poultry meat processing and soybean/oilseed processing facility exhibited androgenic activity comparable to effluent concentrations. No biological activity was detected above MDL in sediment samples. Known estrogenic and androgenic chemical concentrations quantified using targeted analytical methods (HPLC/MS-MS) did not completely explain all measured biological activity, confirming the added value of bioassays in water quality screening applications. Future aquatic-species tissue analysis, may provide insight regarding potential effects of exposure to detected mixtures of biologically active contaminants. Abstract does not necessarily reflect USEPA views or policy.

Impact/Purpose

The existence of complex mixtures of anthropogenically-derived chemicals in freshwater environments has long been established, yet water treatment processes eliminate contaminants with variable efficiency. We previously evaluated agricultural, municipal, and industrial impacted surface and source waters for hundreds of organic chemicals as well as biological activity indicative of potential adverse physiological outcomes. Commercial food, beverage, and feedstock processing facilities also produce wastewater with complex chemical mixtures and are a probable source of bioactive contaminants. However, current monitoring of these wastewaters is primarily focused on basic constituents including, pH, dissolved oxygen, and suspended solids. Here, we investigated in vitro biological activity indicative of potential endocrine disrupting contaminants in wastewater effluent from food processing plants across the United States. Chemical concentrations quantified using targeted analytical methods could not completely explain the cumulative bioassay concentrations high enough to potetially ellicit adverse physiological effects in aquatic organisms in almost half of the wastewater effluent samples. Results of this study maintain the importance of applying non-targeted effects-based methods alongside targeted analytical methods during water quality screening. Further, wastewater from the food processing plants assessed in the study likely contain contaminants beyond those currenty monitored in the wastewater types.

Citation

MedlockKakaley, E., N. Evans, B. Blackwell, R. Hofer, L. Hubbard, P. Bradley, D. Kolpin, AND Dan Villeneuve. Biological Activity in U.S. Food Processing Plant Effluent. Society of Environmental Toxicology and Chemistry, Pittsburgh, PA, November 13 - 17, 2022.