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This research project aims to investigate the contamination of pasture by flooding rivers as a potential source of dioxins and PCBs in cows' milk.
<p>The following samples that were collected for project C01007 from farms with flood-prone pasture and from nearby control farms that do not flood will be analysed:<br> <ul>
<li>12 additional milk samples collected during October 1998
<li>37 milk samples collected during August 1999
<li>17 soil samples collected during October 1998
<li>17 animal feed samples collected in March 1999
<li>40 soil samples collected during August 1999
<li>18 grass samples collected during August 1999
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<p>The results of these analyses will be interpreted together with those obtained in C01007. Further statistical investigations will be carried out, including principal component analysis to characterise the dioxin and PCB congener profiles in milk and other matrices.
<p>Comparison between the milk samples collected in October 1998 and August 1999 is expected to provide insight into the variation of dioxin and PCB concentrations in successive grazing seasons.
<p>Analysis of the feed samples will allow the relationship between the dioxin and PCB patterns in feed and the changes in dioxin and PCB concentrations in milk between October 1998 and March 1999 to be assessed.
The concentrations and patterns of dioxins and PCBs in soil and/or grass samples will be compared with matched milk samples. This is expected to be informative in determining the significance of flooding as a pathway contributing to the presence of dioxins and PCBs in milk from cows grazing on flood-prone pasture.
<p>The aim of the current project is to analyse matched soil, grass and feed samples collected during the original project as well as some milk samples that were collected in August 1999.
This will provide valuable data on the correlation between the patterns and levels of dioxins and PCBs in corresponding samples of environmental media (grass and soil) and cows' milk form flood-prone and control sites.
This will also provide new insights into the transfer and uptake of dioxins and PCBs into cows' milk from feed as well as from environmental media.
Sediment in rivers flowing through industrial or urban areas can contain relatively high levels of dioxins and polychlorinated biphenyls (PCBs).
<p>Consequently deposition of contaminated sediment onto floodplains when rivers flood could cause an increase in the levels of dioxins and/or PCBs in milk from cows grazing on flood-prone pasture.
<p>This project is an extension to a previous study (project C01007). The original study showed that:<br><ul>
<li>cows' milk from flood-prone farms on contaminated river reaches contained significantly higher dioxin and PCB WHO-TEQ than milk samples from matched control sites;
<li>the main impact of flooding appears to result from cumulative depositions of contaminated silt onto floodplains rather than individual flooding events; and
<li>the mean WHO-TEQ values for milk from flood-prone farms on the Doe Lea/Rother/Don and the Trent river systems, which are polluted, were at least twice that for flood-prone farms on the River Dee.
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<p>However, although matched samples of soil, grass and feed as well as milk were collected in the original study, only milk samples collected in October 1998 and March 1999 were analysed.
<P>
The final report, "<a href="http://www.foodbase.org.uk/results.php?f_report_id=196" target="_new">Study of the Effects of Flooding on Concentrations of PCDD/Fs and PCBs in Milk from Cattle Grazing on Affected Pastureland</a>" is available at Foodbase, an open access repository of the <acronym title="Food Standards Agency">FSA</acronym>.
<p> Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research webpage</a>.