Invertebrate mercury bioaccumulation in permanent, seasonal, and flooded rice wetlands within California's Central Valley
Invertebrate mercury bioaccumulation in permanent, seasonal, and flooded rice wetlands within California's Central Valley
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DOI：
10.1016/j.scitotenv.2009.10.030
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发表时间：
2010-01-01
影响因子：
9.8
通讯作者：
Eagles-Smith, Collin A.
中科院分区：
文献类型：
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作者：
Ackerman, Joshua T.;Miles, A. Keith;Eagles-Smith, Collin A.
在春夏两季，我们研究了加州中央谷农业区四种最主要的湿地生境（白米、野生稻、永久湿地和浅淹休耕地）中甲基汞（MeHg）的生物利用度。在水稻生长季节前后的两个时间段（共96个样本），分别对4个复制湿地生境（共8个湿地）的入口、中心和出口的2个水生大型无脊椎动物类群的MeHg和THg浓度进行了采样。总体而言，刺尾科（刺尾科，背游泳者：1.18 +/- 0.08 μ g g（-1）干重[dw]）中THg浓度（平均标准误差）高于刺尾科(刺尾科，水船工：0.89 +/- 0.06 μ g（-1) dw, MeHg: 0.74 +/- 0.05 μ g g(-1) dw）。甲螨科中甲基汞浓度与THg浓度呈正相关（R(2) = 0.80）， 88%的THg以甲基汞形式存在。湿地生境类型对水生无脊椎动物THg浓度有重要影响，但这种影响取决于采样时间和分类群。特别是在永久湿地中，野蠓科的THg浓度高于白米，而薏虫科的THg浓度则高于白米。野生稻，或浅淹的休耕地。稻蠓科的THg浓度在水稻生长季结束时高于汛期，而稻蠓科的THg浓度在不同时期之间没有差异。湿地生境类型对水稻生长的影响在水稻生长季末更为明显，在此期间，柽柳THg浓度在永久湿地中最高。此外，无脊椎动物THg浓度在湿地出水口高于入水口。研究结果表明，虽然无脊椎动物THg浓度从湿地淹水到退潮期间呈上升趋势，但白米、野生稻和浅淹休耕地等临时淹水生境的无脊椎动物THg或MeHg浓度并不高于永久湿地。Elsevier B.V.出版
We examined methylmercury (MeHg) bioavailability in four of the most predominant wetland habitats in California's Central Valley agricultural region during the spring and summer: white rice, wild rice, permanent wetlands, and shallowly-flooded fallow fields. We sampled MeHg and total mercury (THg) concentrations in two aquatic macroinvertebrate taxa at the inlets, centers, and outlets of four replicated wetland habitats (8 wetlands total) during two time periods bounding the rice growing season and corresponding to flood-up and pre-harvest (96 total samples). In general, THg concentrations (mean standard error) in Notonectidae (Notonecta, back swimmers: 1.18 +/- 0.08 mu g g(-1) dry weight [dw]) were higher than in Corixidae (Corisella, water boatmen; 0.89 +/- 0.06 mu g g(-1) dw, MeHg: 0.74 +/- 0.05 mu g g(-1) dw). MeHg concentrations were correlated with THg concentrations in Corixidae (R(2) = 0.80) and 88% of THg was in the MeHg form. Wetland habitat type had an important influence on THg concentrations in aquatic invertebrates, but this effect depended on the sampling time period and taxa. In particular, THg concentrations in Notonectidae, but not Corixidae, were higher in permanent wetlands than in white rice. wild rice, or shallowly-flooded fallow fields. THg concentrations in Notonectidae were higher at the end of the rice growing season than near the time of flood-up, whereas THg concentrations in Corixidae did not differ between time periods. The effect of wetland habitat type was more prevalent near the end of the rice growing season, when Notonectidae THg concentrations were highest in permanent wetlands. Additionally, invertebrate THg concentrations were higher at water outlets than at inlets of wetlands. Our results indicate that although invertebrate THg concentrations increased from the time of flood-up to draw-down of wetlands, temporarily flooded habitats such as white rice, wild rice, and shallowly-flooded fallow fields did not have higher THg or MeHg concentrations in invertebrates than permanent wetlands. Published by Elsevier B.V.