Low levels of persistent organic pollutants (POPs) in New Zealand eels reflect isolation from atmospheric sources Niklas Holmqvist a, * , Patrik Stenroth b , Olof Berglund a , Per Nystro ¨m b , Karin Olsson b , Don Jellyman c , Angus R. McIntosh d , Per Larsson a a Department of Ecology, Section of Ecotoxicology, Ecology Building, Lund University, SE-223 62 Lund, Sweden b Department of Ecology, Section of Limnology, Ecology Building, Lund University, SE-223 62 Lund, Sweden c National Institute of Water and Atmospheric Research Ltd., PO Box 8602, Christchurch, New Zealand d School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand Received 18 January 2005; accepted 19 August 2005 Low levels of PCBs found in New Zealand eels reflect isolation from atmospheric sources while DDTs levels are determined by land use. Abstract Polychlorinated biphenyls (PCBs) and organic pesticides (i.e., DDTs) were measured in long finned eels (Anguilla dieffenbachii) in 17 streams on the west coast of South Island, New Zealand. Very low levels of PCBs and low levels of ppDDE were found. The concentrations of PCBs and ppDDE were not correlated within sites indicating that different processes determined the levels of the two pollutants in New Zealand eels. The PCBs probably originate from atmospheric transport, ppDDE levels are determined by land use and are higher in agriculture areas. The low contamination level of these aquatic systems seems to be a function of a low input from both long and short-range transport as well as few local point sources. No correlation could be found between lipid content and persistent organic pollutants (POPs) concentration (as shown in previous studies) in the eels which could be explained by low and irregular intake of the pollutants. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Persistent organic pollutants; New Zealand; Eels; Atmospheric transport; Land use 1. Introduction Because they are driven by temperature and their volatility, persistent organic pollutants (POPs) are transported in the at- mosphere all over the world. The ‘‘global distillation theory’’ predicts that in the northern hemisphere POPs (e.g., PCB and DDT) are transported towards the Arctic by multiple revolati- lazation events in the high temperature regions (Wania and Mackay, 1993). In the southern hemisphere the opposite latitudinal relationship could be expected using the same prin- ciples invoked in the northern hemisphere i.e., a global trans- port towards the Antarctic regions. Several POPs have been found in both Arctic and Antarctic ‘‘pristine’’ areas (e.g., Larsson et al., 1992). Generally, levels found in the Antarctic are lower than levels found in Arctic areas. In fact, levels found in polar bears and indigenous people in the Arctic are among the highest detected worldwide (AMAP, 2004). New Zealand is a rather industrialized country with many probable point sources of POPs. However, apart from estuarine regions (e.g., Hickey et al., 1995), there have been few studies reported on the level of contamination of POPs in this region of the world. Both long-range transport from the more indus- trial areas in Asia and short-range transport from local point * Corresponding author. Department of Chemical Ecology/Ecotoxicology, Ecology Building, Lund University, 22362 Lund, Sweden. Tel.: C46 46 2224598; fax: C46 46 2223790. E-mail address: niklas.holmqvist@ekol.lu.se (N. Holmqvist). 0269-7491/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2005.08.052 Environmental Pollution 141 (2006) 532e538 www.elsevier.com/locate/envpol