The global re-cycling of persistent organic pollutants is strongly retardedbysoils WendyA.Ockenden a,1 ,KnutBreivik b ,SandraN.Meijer a ,EilivSteinnes c , Andrew J. Sweetman a ,KevinC.Jones a, * a Environmental Science Department, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster LA1 4YQ, UK b Norwegian Institute for Air Research (NILU), PO Box 100, N-2027, Kjeller, Norway c Department of Chemistry, Norwegian University of Science and Technology, N-7491, Trondheim, Norway Received 14 January 2002; accepted 29 March 2002 ‘‘Capsule’’: C-rich soils of the northern hemisphere appear to be serving as sinks for POPs and preventing their transfer to the Arctic. Abstract ‘Persistent organic pollutants’ (POPs) are semi-volatile, mobile in the environment and bioaccumulate. Their toxicity and pro- pensityforlong-rangeatmospherictransport(LRAT)hasledtointernationalbans/restrictionsontheiruse/release.LRATofPOPs may occur by a ‘single hop’ or repeated temperature-driven air–surface exchange. It has been hypothesised that this will result in global fractionation and distillation—with condensation and accumulation in polar regions. Polychlorinated biphenyls (PCBs)— industrial chemicals banned/restricted in the 1970s—provide a classic illustration of POP behaviour. A latitudinally-segmented global PCB inventory has been produced, which shows that  86% of the 1.310 6 tonnes produced was used in the temperate industrialzoneofthenorthernhemisphere.Aglobalsurveyofbackgroundsurfacesoilsgivesevidencefor‘fractionation’ofPCBs. More significantly, however, very little of the total inventory has ‘made the journey’ via primary emission and/or air–surface exchange and LRAT out of the heavily populated source regions, in the 70 years since PCBs were first produced. Soils generally occlude PCBs, especially soils with dynamic turnover of C/bioturbation/burial mechanisms. This limits the fraction of PCBs availableforrepeatedair–soilexchange.Theforestedsoilsofthenorthernhemisphere,andotherC-richsoils,appeartobeplaying an important role in ‘protecting’ the Arctic from the advective supply of POPs. Whilst investigations on POPs in remote environ- mentsareimportant,itisimperativethatresearchersalsoseektobetterunderstandtheirreleasefromsources,persistenceinsource regions,andthesignificantlossmechanisms/globalsinksofthesecompounds,iftheywishtopredictfuturetrends. # 2002Elsevier ScienceLtd.Allrightsreserved. 1. Introductory remarks The global transport of persistent organic pollutants (POPs)isofcurrentinterestandconcern(Kleckaetal., 2000). Industrial (e.g. PCBs), agricultural (e.g. DDT, Lindane) and by-product (e.g. polychlorinated dibenzo- p-dioxins and -furans) chemicals have been detected in remote Arctic and Antarctic regions, far from the areas of their use and emission. Concern over the tox- icology of these compounds has led to international effortstocontroltheiruseanddisposalandunderstand their global distribution, fate and behaviour. In 1998, the United Nations Economic Commission for Europe (UNECE) protocol (UNECE, 1998) on the long-range trans-boundary air pollution of POPs was signed by 36 countries, although it is still to be ratified. Risk criteria were used to identify 16 substances for inclusion on the UNECEPOPslist.Theprotocolaimstoeliminatetheir useand/ordischarges/emissions.Internationalmeasures have since moved to a larger arena. The United Nations’ Environment Programme (UNEP) is develop- ing a similar protocol, with the objective of global eliminationofcertainPOPs. 0269-7491/03/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved. PII:S0269-7491(02)00204-X Environmental Pollution 121 (2003) 75–80 www.elsevier.com/locate/envpol * Corresponding author. Tel.: +44-1524-593972; fax: +44-1524- 593985. E-mail address: k.c.jones@lancaster.ac.uk (K.C. Jones). 1 Present address: TheScientificWorld, Cherwell Innovation Cen- tre, 77 Heyford Park, Upper Heyford, Bicester, Oxfordshire OX25 5HD,UK.