Distribution and persistence of the anti sea-lice drug teflubenzuron in wild fauna and sediments around a salmon farm, following a standard treatment Ole B. Samuelsen a, ⁎, Bjørn T. Lunestad b , Rita Hannisdal b , Raymond Bannister a , Siri Olsen a , Tore Tjensvoll b , Eva Farestveit a , Arne Ervik a a Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen, Norway b National Institute of Nutrition and Seafood Research, P.O. Box 2029 Nordnes, N-5817 Bergen, Norway HIGHLIGHTS • Distribution of teflubenzuron was studied in the marine environment after medication • Teflubenzuron containing organic particles were collected 1100 m from the farm • Teflubenzuron persists in the sediment for a prolonged time • Residues were found in nearly all species of biota collected • Residues found in saith and crab exceeded the MRL value given for farmed salmon abstract article info Article history: Received 25 September 2014 Received in revised form 25 November 2014 Accepted 25 November 2014 Available online xxxx Editor: Adrian Covaci Keywords: Aquaculture Teflubenzuron Environmental distribution Sediment Fish Crustaceans Food safety The salmon louse (Lepeoptheirus salmonis) is a challenge in the farming of Atlantic salmon (Salmo salar). To treat an infestation, different insecticides are used like the orally administered chitin synthetase inhibitor teflubenzuron. The concentrations and distribution of teflubenzuron were measured in water, organic particles, marine sediment and biota caught in the vicinity of a fish farm following a standard medication. Low concentra- tions were found in water samples whereas the organic waste from the farm, collected by sediment traps had concentrations higher than the medicated feed. Most of the organic waste was distributed to the bottom close to the farm but organic particles containing teflubenzuron were collected 1100 m from the farm. The sediment under the farm consisted of 5 to 10% organic material and therefore the concentration of teflubenzuron was much lower than in the organic waste. Teflubenzuron was persistent in the sediment with a stipulated halflife of 170 days. Sediment consuming polychaetes had high but decreasing concentrations of teflubenzuron through- out the experimental period, reflecting the decrease of teflubenzuron in the sediment. During medication most wild fauna contained teflubenzuron residues and where polychaetes and saith had highest concentrations. Eight months later only polychaetes and some crustaceans contained drug residues. What dosages that induce mortality in various crustaceans following short or long-term exposure is not known but the results indicate that the concentrations in defined individuals of king crab, shrimp, squat lobster and Norway lobster were high enough shortly after medication to induce mortality if moulting was imminent. Considering food safety, saith and the brown meat of crustaceans contained at first sampling concentrations of teflubenzuron higher than the MRL-value set for Atlantic salmon. The concentrations were, however, moderate and the amount of saith fillet or brown meat of crustaceans to be consumed in order to exceed ADI is relatively large. © 2014 Elsevier B.V. All rights reserved. 1. Introduction The copepod ecto-parasite salmon louse (Lepeoptheirus salmonis, Krøyer 1837) is the major challenge in the production of Atlantic salmon (Salmo salar) in Europe and North America. Infestation with the parasite reduces the general welfare of the farmed fish and causes economic loss due to reduced growth, increased mortality and downgrading of fish quality (Burka et al., 2012; Costello, 2006, 2009; MacKinnon, 1997; Pike and Wadsworth, 2000). Furthermore, salmon lice derived from aquacul- ture sources may negatively impact the wild populations of sea trout and migrating wild post-smolts of Atlantic salmon (Costello, 2009; Wagner et al., 2008). Science of the Total Environment 508 (2015) 115–121 ⁎ Corresponding author. http://dx.doi.org/10.1016/j.scitotenv.2014.11.082 0048-9697/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv