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Fate of oxytetracycline in streams receiving aquaculture discharges: Model simulations
Author(s) -
Rose Peter E.,
Pedersen Joel A.
Publication year - 2005
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/03-640.1
Subject(s) - settling , biosolids , water column , environmental science , sediment , oxytetracycline , hydrology (agriculture) , streams , water quality , environmental chemistry , zoology , chemistry , environmental engineering , ecology , biology , geology , paleontology , biochemistry , antibiotics , computer network , geotechnical engineering , computer science
The potential aquatic fate of oxytetracycline (OTC) in streams receiving discharge from fish hatcheries was examined using the Water‐Quality Analysis Simulation Program (WASP, Ver 6.1) model. The modeled 4.4‐km stream network included a settling pond, a receiving segment, and two downstream segments. Attainment of quasi‐steady state concentrations (concentration variation, <7.5 mg kg −1 ) in the sediment layers of the receiving segment and first downstream segment required several years. Median water‐column concentrations (truly dissolved and colloid‐ and particle‐associated) were 0, 0.57, 0.80, and 0.83 ng L −1 in the settling pond, receiving segment, first downstream segment, and second downstream segment. Truly dissolved fractions in the water column during dosing were 16% in the settling pond, 64% in the receiving segment, and approximately 78% in the river segments. Concentrations declined 20‐ to 400‐fold, depending on the segment considered, within 1 d of dosing. Truly dissolved fractions in the water column after cessation of dosing were 96% in the settling pond and approximately 78% in the river segments. Expected sediment‐bound concentrations were approximately 4 mg kg −1 in the receiving segment during dosing, with a median annual concentration of approximately 1.5 mg kg −1 . Expected concentrations in downstream sediments were 0.2 mg kg −1 or less. Sensitivity analyses indicated the most important factors influencing fate under the hydrodynamic conditions simulated were settling‐pond biosolids load, biosolids settling velocity, OTC depuration kinetics from biosolids, and OTC river particle‐water distribution coefficient(s).