Chronic exposure of adults and embryos of Pandalus borealis to oil causes PAH accumulation, initiation of biomarker responses and an increase in larval mortality Renée Katrin Bechmann a, * , Bodil Katrine Larsen a,1 , Ingrid Christina Taban a , Lars I. Hellgren b , Per Møller b , Steinar Sanni a,c a International Research Institute of Stavanger/IRIS-Biomiljø, Mekjarvik 12, 4070 Randaberg, Norway b Technical University of Denmark, Dept. of Systems Biology, DK-2800 Kgs. Lyngby, Denmark c University of Stavanger, Faculty of Science and Technology, N-4036 Stavanger, Norway article info Keywords: Oil–water dispersion (OWD) Pandalus borealis Embryo Larvae Biomarkers PAH abstract Adult shrimps (Pandalus borealis) and their embryos were exposed to an oil–water dispersion (OWD) at concentrations of 0.015, 0.06 and 0.25 mg/L using a continuous flow system. Lysosomal membrane sta- bility was analysed in haemocytes using the neutral red retention assay and an alkaline unwinding assay was used to measure DNA damage in hepatopancreas tissue. Exposure to oil induced concentration and time dependent biomarker responses in adult shrimps together with the accumulation of PAH in their tissues. Oil exposure of shrimp embryos caused increased mortality in the resultant larvae, even if the larvae were kept in clean water after hatching. There were minor differences observed in larval stage development times in the first part of the experiments. The fatty acid composition of embryos exposed to oil was different to that of non-exposed larvae. PAH tissue concentration and biomarker responses cor- related to the reduced survival of the shrimp larvae. Ó 2010 Published by Elsevier Ltd. 1. Introduction We have studied the effects of chronic exposure to oil–water dispersion (OWD) on the Northern shrimp Pandalus borealis. The effects on survival and development of shrimp larvae following embryo exposure to oil was studied, and in the same experiments biomarker responses and tissue concentrations of polycyclic aromatic hydrocarbons (PAH) were analysed in the parent shrimps. The main objective was to investigate if significant biomarker responses and increased tissue concentration of PAH could be detected in adult shrimps at lower oil concentrations than those affecting survival and development of shrimp early life stages. P. borealis is an ecologically and commercially important shrimp species found in colder parts of the Atlantic and Pacific Oceans. The adults are hyperbenthic, during daytime, they rest and feed on or near the bottom, and at night, substantial numbers migrate vertically into the water column, feeding on zooplankton (Bergs- tröm, 2000). Hence this species can be found in the whole water column and is a relevant organism to use in future monitoring of regular discharges by oil and gas operators or following accidental discharges of petroleum compounds. The shrimps were exposed to OWD to simulate produced water discharges or a sub-sea blow out of oil (Rye et al., 2000). Produced water is primarily formation water trapped in the petroleum reservoirs, but brought to the sur- face along with oil or gas during petroleum production. The water is separated from the oil on the offshore oil production installa- tions and continuously discharged into the surrounding water masses. A sub-sea blow-out of oil at depths below 100 m will also have a size distribution of oil droplets between 2 and 20 lm(Rye et al., 2000), similar to PW and the oil droplet size generated in our exposures. This size range of oil droplets are not expected to rise, but to remain within the underwater plume generated by the blow-out (Rye et al., 2000). Firstly, we analysed a selection of biomarker responses and the tissue concentration of PAH in adult shrimps exposed to increasing but low oil concentrations. This was done to investigate if PAHs were accumulated in detectable concentrations in shrimp tissues even when exposed to relatively low concentrations of oil, and to assess the suitability of the selected biomarkers for environmental monitoring of shrimps in regions where oil and gas activities exist or are proposed. The selected biomarkers were lysosomal mem- brane stability, a general health indicator, and alkaline unwinding, an indicator of DNA damage. The lysosomal membrane stability was analysed using the neutral red retention (NRR) assay (Lowe et al., 1995; Moore et al., 2008), and a Microplate Assay was used 0025-326X/$ - see front matter Ó 2010 Published by Elsevier Ltd. doi:10.1016/j.marpolbul.2010.07.010 * Corresponding author. Tel.: +47 51 87 55 10; fax: +47 51 87 55 40. E-mail address: rkb@iris.no (R.K. Bechmann). 1 Present address: Technical University of Denmark, DTU Aqua, Section for Aquaculture, The North Sea Research Centre, P.O. Box 101, DK-9850 Hirtshals, Denmark. Marine Pollution Bulletin 60 (2010) 2087–2098 Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul