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(207) Long-term effects and bioaccumulation of produced water components (PAH and phenols) in Acartia tonsa. Johnsen, Hanne 1, Frost, Tone1, Neverdal, Gunhild1, Johnsen, Ståle1, 1 ABSTRACT- Long-term effects and bioaccumulation of two groups of persistent compounds found in produced water discharges from offshore oil production have been examined, based on available knowledge that these compounds are expected to contribute most to the chronic toxicity in produced water. 10 chronic experiments were carried out, 5 experiments with polycyclic aromatic hydrocarbons (PAH) and 5 experiments with alkylated phenols. The experiments were performed using a continuous flow-through system, allowing exposure of the copepod Acartia tonsa to five different concentration levels of the selected produced water component and five different exposure times. Radioactive labeled chemicals were used to be able to obtain control of the exposure concentrations. The concentration level chosen in each experiment were based on acute toxicity tests with Acartia tonsa, performed in advance of each chronic experiment. Egg production per female per day, the success of hatching, survival of nauplii and the cephalothorax length of the copepods were chosen as effect parameters. To be able to relate the observed effects to the body residue concentration, a simultaneous study of the long term effects and bioaccumulation were performed in the same setup. The results from these experiments give us three dimensional dose-response curves used as input data for the risk assessment tool DREAM (Dose related Risk and Effect Assessment Model), which is used to quantify and predict the potential long-term environmental impacts of produced water discharges from offshore oil production. NOEC-levels (No Observable Effect Concentration) and LOEC-values (Lowest Observable Effect Concentration) will be calculated and compared with the concentration level found in produced water. The environmental risk approach in DREAM is described in detail in another abstract (Smit et al.) Key words: produced water, long-term effects, PAH and phenols, risk assessment |
