Laboratory and on-farm studies on the bioaccumulation and elimination of dioxins from a contaminated mineral supplement fed to dairy cows
Laboratory and on-farm studies on the bioaccumulation and elimination of dioxins from a contaminated mineral supplement fed to dairy cows
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DOI：
10.1021/jf0480997
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发表时间：
2005-03-23
影响因子：
6.1
通讯作者：
Smith, DJ
中科院分区：
文献类型：
--
作者：
Huwe, JK;Smith, DJ
用一种被二恶英污染的矿物质补充剂研究了二恶英在两头奶牛体内的生物积累和消除。将添加物与总维持日粮混合饲喂40 d，再饲喂40 d的非强化日粮。每周两次在牛奶和奶牛的选定组织中测量二恶英和共面多氯联苯（PCBs），一次在死亡时（停药后第10天），一次在屠宰时（停药后第40天）。二恶英和多氯联苯很容易转移到牛奶中，在稳定状态下，总毒性当量浓度是饮食中乳脂的6倍。生物富集与氯化次数成反比。牛奶中二恶英和多氯联苯的消除是分两阶段进行的。除了1、2、3、4、6、7、8-七氯二恶英和两种八氯同系物外，牛奶中的二恶英和呋喃的半衰期在a期约为3-5天，在β期约为35-50天。PCB-169的半衰期较长：11天（α）和200天（β）。当对明尼苏达州农场的牛奶和饲料样本进行分析时，发现牛奶中的二恶英含量没有升高。这些农场使用了类似的受污染矿物质补充剂。结果显示，尽管矿物质补充剂中的二恶英有可能在生物体内积累，但将其稀释到总饮食中足以防止这些农场牛奶中二恶英浓度的显著上升。
A dioxin-contaminated mineral supplement was used to study the bioaccumulation and elimination of dioxins in two dairy cows. The supplement was mixed into the total maintenance ration and fed to the cows for 40 days after which unfortified diets were fed for 40 additional days. Dioxins and coplanar polychlorinated biphenyls (PCBs) were measured twice a week in the milk and in selected tissues of the cows, one at death (day 10 of withdrawal) and one at slaughter (day 40 of withdrawal). The dioxins and PCBs were readily transferred into the milk, and at steady state, total toxic equivalents were concentrated 6-fold into the milk fat from the diet. Bioaccumulation was inversely related to chlorination number. The elimination of dioxins and PCBs in milk was biphasic. With the exception of 1,2,3,4,6,7,8-heptachlorodioxin and both octachlorinated congeners, dioxin and furan half-lives in milk were approximately 3-5 days for the a-phase and 35-50 days for the beta-phase. PCB-169 had a longer half-life: 11 (alpha) and 200 days (beta). When milk and feed samples from Minnesota farms that had used similar contaminated mineral supplements were analyzed, no elevated dioxin levels were found in milk. It appeared that although the dioxins from the mineral supplements have the potential to bioaccumulate, dilution into the total diet was sufficient to prevent a significant rise in the dioxin concentrations in the milk at these farms.