No abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractDescription of benthic fauna have traditionally been the most dominating method in offshore environmental impact studies. However, this method has revealed clear limitations. Benthic fauna investigations are retrospective with regard to biological impacts. They are relatively expensive and do not provide information about the impact of discharges in the water column. Today, focus on the water column has increased and the Norwegian Pollution Control Authorities has decided to emphasise on possible biological effects. However, this has not yet been implemented and present monitoring is limited to measurements of chemical concentrations in water and tissue. These data are combined with model simulations of water concentration fields. The rationale behind the change in biomonitoring focus towards biological effects is that one do not necessarily include in monitoring programs those chemicals that cause effects. Therefore, it is considered a better strategy to monitor effects directly. Some biological effect parameters (by definition named general biomarkers) integrate responses to several classes of chemicals in the environment, other parameters respond more specifically to special compounds. For environmental screening purposes, it is important to select the type of biomarkers which is most relevant for the type of pollution expected and the species investigated. If effects are indicated with a screening biomarker, a more detailed environmental analysis will be required. Supplementary biomarker methods and chemical analyses can then decide the real size and cause of the impact in a stepwise and cost-effective manner.