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Abstract Veterinary antiparasitic pharmaceuticals have been detected in surface waters and several of these pharmaceuticals act on the nervous system on the target organisms implying that neurological effects also might be of concern in non-target animals such as fish. We tested if exposure to antiparasitic pharmaceuticals affect swimming activity in 6 days old zebrafish larvae. The results revealed that most pharmaceuticals did not cause any effects in swimming activity. However, larvae exposed to 0.58 mg/L doramectin displayed reduced swimming activity even though they were classified as normal, having no morphological abnormalities. [ABSTRACT FROM AUTHOR]

Abstract: For reliable monitoring of environmental improvement, the PCB contaminated bay Örserumsviken on Sweden’s Baltic coast was investigated prior to remediation. We examined PCB congener patterns and the relative toxic potential of PCBs in extracts of three matrices: bottom sediment, settling particulate matter and the dissolved phase (obtained from semi-permeable membrane devices). Congener patterns were similar in all matrices. Three fractions were isolated from the extracts: (1) aliphatic and monocyclic aromatic compounds (MAC-fraction), (2) dicyclic aromatic compounds (DAC-fraction), including PCBs, and (3) polycyclic aromatic compounds (PAC-fraction), including PAHs. Total extracts and fractions were injected into newly fertilised rainbow trout eggs. At larval stage, hepatic EROD activities were quantified. Though high, the PCB contamination could explain only an estimated 1–5% of the total EROD induction. The order of EROD induction potential was: total extract>PAC-fraction>DAC-fraction>MAC-fraction in all matrices, suggesting that in Örserumsviken PACs made a larger contribution to the EROD induction potential than PCBs and other DACs. [Copyright &y& Elsevier]

• Nitrate retention was estimated by flow-proportional sampling and sensors. • Summer nutrient retention was efficient (%), but was a small part of yearly mass. • Organic nitrogen retention was efficient in the first winter, but not the second. • Sensors are essential for evaluating nutrient dynamics and retention. Constructed free water surface wetlands (CWs) are used to reduce nutrient and sediment loads to receiving waters in highly impacted catchments by e.g., agricultural land use. In this paper, we evaluated the retention effectiveness of a Swedish CW in two consecutive hydrological years, 3–4 years after construction respectively. We compared nutrient loads based on concentrations from flow-proportional sampling (C fp) and turbidity and nitrate concentrations measured with optical sensors (C s). CW's retention was estimated based on differences between inlet and outlet concentrations and flow (Q) at both the inlet and outlet (2Q), or only at the inlet (1Q). In the first year (2012/2013), with a cold winter (mean topsoil temperature −0.2 °C), nitrate-nitrogen (NO 3 N) retention was 32% (C fp and C s , 2Q). In the second year, with a mild winter (mean topsoil temp 1.8 °C) and less water runoff, the corresponding values were 37% (C fp , 2Q) and 39% (C s , 2Q). Nitrate-nitrogen retention was significantly correlated to water residence time and temperature, and was most effective relative to the load (80%) in summer and least effective (40%) in winter. Quantitatively, however, summer NO 3 N retention contributed only 7% (2Q) or 8% (1Q) of yearly NO3N mass retention. Particulate phosphorus (PP) concentrations were significantly correlated with suspended solids (SS) concentrations at both inlet and outlet. Seasonal PP retention (C fp , 2Q) was related to particle residence time estimated from turbidity measurements by sensors, and was less effective in the cold winter (3%) than in the mild winter (32%) (C fp , 2Q). Yearly retention (2Q) as a mean of the two years was: SS 40%, total P 36%, PP 34%, dissolved reactive P 30%, total N 56%, NO 3 N 35%, organic N 75%, and organic C 30%. Overall, the wetland satisfactorily removed nutrients from agricultural drainage water. However, longer-term studies over a range of flow and temperature conditions are needed to evaluate climate conditions and hydrological residence time as key factors in nutrient removal efficiency. [ABSTRACT FROM AUTHOR]