Spatial biomonitoring of persistent organic pollutants in Iran: a study using locally produced butter† Amirali Jafari, Claudia Moeckel and Kevin C. Jones * Received 5th February 2008, Accepted 28th April 2008 First published as an Advance Article on the web 21st May 2008 DOI: 10.1039/b802061b Butter is a readily collected, integrative and inexpensive sampling matrix for the spatial mapping of persistent organic pollutants (POPs) at the national or regional scale. As air-plant-animal transfers generally supply the POPs reaching butter lipid, this study used butter for an initial evaluation of the occurrence, levels and distribution of POPs (selected organochlorine pesticides and PCBs) in Iran, a country for which very little information on usage, emissions and environmental burdens of these compounds exists. Fifty samples from rural and urban areas, in the north, west and central regions of the country were collected from local farms in spring 2007. Concentrations of p,p 0 -DDT and p,p 0 -DDE varied widely by a factor of 1000 and 370 (8450 pg g 1 lipid and 46 800 pg g 1 lipid on average). The highest levels, found mainly in urban areas in the centre of the country, were amongst the highest reported in the world. PCB concentrations (4320 pg g 1 lipid on average) varied by a factor of 160 and were highest close to urban centres and lowest in the rural northwest. Although Iran is not known for widespread PCB usage in the past, concentrations were higher than a ‘global average’ reported in a butter survey in 2001. This simple sampling approach could be adopted in other regions where cows graze, as part of an initial screening to help meet obligations under the Stockholm Convention. Introduction Spatial variations in persistent organic pollutants (POPs) need to be assessed on the national, regional and global scale, to evaluate the effectiveness of international treaties designed to eliminate or reduce their release to the environment. Signatory countries to the Stockholm Convention are required to produce a national implementation plan (NIP), to identify and reduce sources, and to monitor for effectiveness in reducing ambient levels and human/wildlife exposure. 1 Under the United Nations Environ- ment Programme (UNEP) a global series of regional reports was produced, which—where possible—summarised measured ambient data in order to evaluate regional hotspots etc. The reports for some regions were relatively ‘data rich’ (e.g. Europe, North America and Asia). 2–4 In contrast, there is still a lack of information for the Middle East. 5 In 2003, UNEP produced a report on the objectives and possible design of a Global Monitoring Network for POPs. 6 Mindful of the costs of sampling and analysis, the report considered the environmental and biological matrices which could be used to perform rapid reconnaissance and assessment of POP levels and distributions. Often there may be interest in an initial, relatively cheap and easy evaluation of a country or region, which has little or no published data or ‘in house’ expertise for environmental sampling and analysis. 6 Air sampling, often using innovative passive sampling techniques, can give useful information to compare with other regions where data are more plentiful. 6,7 However, even passive air sampling requires local operatives for the samplers and return visits to the sites. Iran is a country for which very little information on POPs exists. In 2007, the opportunity to visit and conduct a spatial survey of Iran arose. Less than 6 months and less than $10 000 was available to conduct a study as part of a Masters degree. This figure had to include the flights from the UK to Iran, internal travel in Iran, sampling and analytical costs. Consideration was therefore given to how data could be obtained cheaply, quickly and easily from a single visit to the country. Deployment of passive air samplers was not an option, because they would require a return visit. Butter was selected as the sampling medium instead. Several studies have used butter to assess environmental contamination with POPs. 8–12 It is a convenient and relatively uniform monitoring medium and reflects the regional and global scale distribution of POPs. 8,9 The high lipid content of butter (typically 80% fat) provides relatively high concentrations of most POPs, with good detection limits and relatively easy analysis. 12 Residues in butter reflect the occurrence of POPs in the cow’s feed (typically pasture grass), which in turn is contaminated via atmospheric deposition of diffusive airborne POPs. Supporting studies show the quantitative link between air concentrations, herbage concentrations, and milk fat concen- trations. 13,14 PCBs and other semivolatile persistent, bio- accumulatory organic contaminants reach human tissue primarily via dietary intake of meat and dairy products (i.e., milk, butter, and cheese) and fish. Cows are therefore one of the main suppliers of these chemicals to humans. 13,14 This paper describes a simple survey, but illustrates how useful information about chemical usage and distribution can be obtained on a national scale from such an exercise. Centre for Chemicals Management and Environmental Science Department, Lancaster Environment Centre, Lancaster, UK LA1 4YQ † Electronic supplementary information (ESI) available: Maps of Iran, showing key features of the country, includes the distribution of pollutants and sites selected for sampling. Tables provide sampling data. See DOI: 10.1039/b802061b This journal is ª The Royal Society of Chemistry 2008 J. Environ. Monit., 2008, 10, 861–866 | 861 PAPER www.rsc.org/jem | Journal of Environmental Monitoring