Bioaccumulation of selected veterinary medicinal products (VMPs) in the blue mussel (Mytilus edulis).

Veterinary medicinal products (VMPs) are widely used within the fish farming industry to control sea lice infestations. There is concern that wild and farmed mussels in the vicinity to these fish farms may be exposed and subsequently bioaccumulate these chemicals, which could pose a threat to human health. To understand the fate of these chemicals in the environment, controlled laboratory exposures were performed to establish the uptake and depuration of selected VMPs in the blue mussel (Mytilus edulis). The VMPs included teflubenzuron, emamectin benzoate and deltamethrin. The effects of salinity on the bioaccumulation of teflubenzuron were also investigated to see whether mussels in brackish waters exhibit different bioaccumulation dynamics. Salinity had no significant effect on the uptake or depuration curves for teflubenzuron down to 15‰. The uptake rate constants (k1) for teflubenzuron, emamectin benzoate and deltamethrin in mussels were 192, 4.82 and 2003, with kinetic bioconcentration factors (BCFs) of 1304, 49 and 2516. Depuration rate constants (k2) were also found to differ between the three VMPs at 0.147, 0.048 and 0.796 for teflubenzuron, emamectin benzoate and deltamethrin, with calculated elimination half-lives (t1/2)of 4.7, 14 and 0.87 days. The longer elimination half-lives for teflubenzuron and emamectin benzoate, suggest that these chemicals accumulate in blue mussels and therefore have the potential to bioaccumulate in wild and farmed mussel populations in the environment.

Routine analysis of hydrocarbons, PCB and PAH in marine sediments using supercritical CO2 extraction

Automated Supercritical Fluid Extraction (SFE), using CO2, was tested and optimised for routine analysis of hydrocarbons (THC), polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) in marine sediments. The aim of the exercise was to reduce the amount of solvents used and to reduce the manual handling time for each sample. The sediments contained elemental sulphur, which was removed during the extraction step using activated Cu. Similar recoveries and reproducibility where found for THC when conventional solvent extractions and SFE where compared. Modifying the CO2 with methanol was necessary to obtain extraction recoveries similar to conventional extraction methods for PCB and PAH.

Ecotoxicological characterization of industrial wastewater--sulfite pulp mill with bleaching.

Different process wastewaters from a sulfite pulp mill with bleaching were characterized by chemical analysis and toxicity tests. The amount of adsorbable organically bound halogen (AOX) from the bleachery was 3.6 kg per ton pulp. The extractable organically bound chlorine was 15% of AOX. Some identified organochlorine compounds in the effluent could be traced in the receiving water. Effluents from the chlorination and alkaline extraction stages and the condensate were the main contributors to the effluent toxicity. The effluents were particularly toxic to the alga Skeletonema costatum. The EC50 value for growth of the alga was 24-29 ml/liter of the total effluent. The toxicity cannot be ascribed to single chemical components in the effluents. Degradation of toxic components occurs after dilution of the effluents in the receiving water. The toxicity may be reduced to 30-50% of the initial toxicity within 1 week. Predictions of toxic effects in the receiving water, based on results of toxicity tests and estimated dilution, indicate that large areas are affected by the discharges. Som observations of the distribution of organisms in the receiving water indicate that predictions from the toxicity tests may be valid.