| dc.description.abstract | In a report published by the Norwegian Environment Agency (2007), diclofenac and ciprofloxacin were listed as pharmaceuticals to further monitor in Norway. Ciprofloxacin and diclofenac are continuously released into the marine ecosystem through wastewater effluents, and there are considerable uncertainties related to the effect these have on the marine ecosystem. This thesis aimed to assess the environmental risks ciprofloxacin, diclofenac, and the binary mixture of these pose to the marine environment by utilizing Mytilus edulis (blue mussels) as a bioindicator. This was performed by combining theoretical calculations of risk quotients, a laboratory exposure study utilizing a multi-biomarker approach to assess potential oxidative stress to M. edulis under environmentally relevant pharmaceutical concentrations, and an investigation of the possible bioaccumulation under these concentrations.
The results from the multi-biomarker approach implied synergistic activity of ciprofloxacin and diclofenac. However, based on the overall results in this thesis, the different pharmaceutical concentrations and the binary mixture did not induce a significant oxidative stress effect in M. edulis. Therefore, it is unlikely that diclofenac and ciprofloxacin pose a significant risk to M. edulis. This was further validated by chemical analysis of the biota, which showed no bioaccumulation in the M. edulis samples, which had been exposed to 500, 1000, and 10 000 ng/L of ciprofloxacin, diclofenac, or the binary mixture of these pharmaceuticals.
However, this thesis recommends that the precautionary principle should be followed since scientific uncertainty is present regarding the risk ciprofloxacin and diclofenac pose to the environment. Antibiotic resistance was not investigated in this thesis. Uncertainties may result in higher risk than what is presented in this thesis. | |