School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
Chemosphere. 2013 Jan;90(1):72-9. doi: 10.1016/j.chemosphere.2012.07.038. Epub 2012 Aug 24.
The first detailed investigation into seasonal variations in PCDD/F, PCB and PBDE concentrations in cows' milk from individual farms was conducted. From August 2009 milk samples were taken at 6 weeks intervals from the bulk tank of 2 farms over a period of one year. Samples of dietary inputs including commercial feed, grass, silage and soil were also collected at 6 weekly intervals from each farm. Detailed animal husbandry information was additionally obtained. For all these samples total TEQ, ∑ICES6 and the ∑7 PBDE congeners was calculated. The results demonstrated that the concentrations of these sets of compounds fluctuate notably over short periods in cows' milk. This variability was such that the highest observed concentrations were nearly double the lowest concentrations detected for both PCDD/Fs and PCBs and PBDEs. Fluctuations between extremes were observed over time periods as short as 6 weeks. Some, but not all, of these variations may be explained by changes in the contaminant concentrations of dietary inputs consumed by the cattle. Changes in contaminant inputs from grass and silage were identified as being the most important source of these fluctuations. Given this variability, the results from PCDD/F and PCB and PBDE monitoring studies may be highly dependent upon when the individual samples were taken. The results have important implications for total diet studies and sampling design.
首次对单个农场牛奶中 PCDD/F、PCB 和 PBDE 浓度的季节性变化进行了详细调查。从 2009 年 8 月开始，在一年的时间里，每隔 6 周从 2 个农场的大罐中采集牛奶样本。还每隔 6 周从每个农场采集包括商业饲料、草、青贮饲料和土壤在内的饲料投入样本。此外，还额外获得了详细的畜牧业信息。对所有这些样品，计算了总 TEQ、∑ICES6 和∑7 PBDE 同系物的浓度。结果表明，这些化合物组在牛奶中短时间内的浓度波动很大。这种可变性如此之大，以至于观察到的最高浓度几乎是检测到的 PCDD/Fs 和 PCBs 和 PBDEs 的最低浓度的两倍。在短短 6 周的时间内就观察到了极端之间的波动。这些变化的一些（但不是全部）可以用牛所食用的饮食污染物浓度的变化来解释。从草和青贮饲料中污染物输入的变化被认为是这些波动的最重要来源。鉴于这种可变性，PCDD/F 和 PCB 和 PBDE 监测研究的结果可能高度依赖于采集个别样本的时间。这些结果对全饮食研究和采样设计具有重要意义。
