Full length article The effects of flooding on dioxin and PCB levels in food produced on industrial river catchments Iain R. Lake a, ⁎, Christopher D. Foxall a , Alwyn Fernandes b , Mervyn Lewis c , Martin Rose b , Oliver White c , Andrew A. Lovett a , Shaun White b , Alan Dowding d , David Mortimer d a School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK b The Food and Environment Research Agency (FERA), Sand Hutton, York YO41 1LZ, UK c Askham Bryan College, Askham Bryan, York YO23 3FR, UK d Food Standards Agency, Aviation House, 125 Kingsway, London WC2B 6NH, UK abstract article info Article history: Received 14 July 2014 Received in revised form 15 January 2015 Accepted 15 January 2015 Available online 7 February 2015 Keywords: Dioxins PCBs Flooding Beef Milk Lamb Food Risk assessment Soil Grass This research examined the effect of regular flooding upon PCDD/F and PCB levels in milk, beef and lamb, pro- duced on the floodplains of industrial river catchments. Our unique dataset included more than 200 samples analysed for PCDD/Fs and PCBs over two data collection phases (1998–1999 & 2008–2010) from working farms. A robust paired study design was adopted with samples taken from flood-prone farms and nearby control farms not subject to flooding. On industrial river catchments regular flooding is associated with higher PCDD/F and PCB levels in soils and grass. This contamination may be transferred to food but the impact varied by food type. These contrasts may be due to physiological differences between animals, the ages at which they are sent to market and differences in animal husbandry. To minimise the risks of producing food on flood-prone land in industrial river catchments, as well as on any land with elevated PCDD/F and PCB levels, this research suggests a number of options. The choice of livestock may be important and as an example in our study beef cattle accumulated PCDD/Fs to a higher degree than sheep. Land management may also play a role and could include minimising the time that livestock spend on such land or feeding commercial feed, low in PCDD/Fs and PCBs, where appropriate. © 2015 Published by Elsevier Ltd. 1. Introduction Polychlorinated dibenzo-p-dioxins and furans (dioxins; PCDD/Fs) and polychlorinated biphenyls (PCBs) are recognised persistent organic pollutants (POPs) and are reported to have negative effects on human health (Schecter and Gasiewicz, 2003). In the past, PCBs were common- ly used in many industrial applications, most notably as insulating and cooling fluids for industrial transformers and capacitors. Conversely PCDD/Fs have never been produced intentionally, but are typically formed through combustion activities or as a by-product of the produc- tion of organo-chlorine chemicals. These compounds are now ubi- quitously present in the environment resulting in concerns relating to their environmental persistence, their bioaccumulation potential, and their toxicity. Health impacts associated with these compounds include immunotoxicity, carcinogenicity and developmental and reproductive effects (Schecter and Gasiewicz, 2003). In more developed countries, industrial combustion emissions are tightly regulated and PCB production has ceased. Consequently, levels of PCDD/Fs and PCBs in the environment (Alcock and Jones, 1996; Schuster et al., 2011), food (Durand et al., 2008; Harrison et al., 1998) and humans (Alivernini et al., 2011; Lignell et al., 2009) are declining. Therefore, the issue is one of managing a historical legacy, complicated by the environmental persistence (congener half-lives measured in decades) of many of these compounds. In less developed countries, the situation is different, and rapid industrialisation has led to increased combustion emissions of PCDD/Fs, which are only starting to be regulat- ed (Zhao et al., 2011). The high levels of PCBs in these settings may be due to leaks and spills, illegal disposal, incineration, historical contami- nation (Xia et al., 2012) or due to the practise of importing waste from more developed regions. In some of these countries, PCDD/F and PCB levels in human tissue are now similar to those in European populations (e.g. China; Shen et al., 2009). In addition PCDD/F and PCB concentra- tions are still rising in some populations (e.g. China; Sun et al., 2011). Understanding the mechanisms through which PCDD/Fs and PCBs can be transferred from the environment to humans is essential to min- imise human exposure. The major route of transfer is through food and around 90% of human intake of PCDD/Fs and PCBs is through this route (Liem et al., 2000). These compounds enter the food chain through sev- eral pathways. Atmospheric deposition over crops for food or animal Environment International 77 (2015) 106–115 ⁎ Corresponding author. E-mail address: I.Lake@uea.ac.uk (I.R. Lake). http://dx.doi.org/10.1016/j.envint.2015.01.006 0160-4120/© 2015 Published by Elsevier Ltd. Contents lists available at ScienceDirect Environment International journal homepage: www.elsevier.com/locate/envint