Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shengyang 110016, China.
J Environ Sci (China). 2010;22(2):198-203. doi: 10.1016/s1001-0742(09)60093-0.
Humic acid is an important pool of heavy metals in sediments. Generally, the presence of refractory humic matter in aquatic systems would decrease the bioavailability of Cd and hence control the bioaccumulation of Cd in benthic animals. In the present work, we applied a suspending system to determine the relative importance of particulate and dissolved fractions of humic acid as Cd sources for the bivalve Meretrix meretrix and to investigate the difference of bioaccumulation characteristics of Cd adsorbed on different fractions of humic acid. The results showed that the bioaccumulation characteristics of Cd from particulate and dissolved fractions of humic acid were apparently different due to biological responses of the clam to the particulates. At Cd concentration of 140 mg/kg, the accumulation of Cd from Cd associated with humic acid mixtures was mainly attributed to the dissolved fractions of humic acid. Compared to particulate fractions, Cd associated with the dissolved fractions of humic acid may be more bioavailable.
腐殖酸是沉积物中重金属的重要来源。一般来说，水生系统中难处理的腐殖质的存在会降低 Cd 的生物利用度，从而控制底栖动物对 Cd 的生物积累。在本工作中，我们采用悬浮体系，确定了腐殖酸的颗粒相和溶解相作为双壳贝类贻贝（Meretrix meretrix）Cd 源的相对重要性，并研究了 Cd 吸附在腐殖酸不同相上的生物积累特征的差异。结果表明，由于贻贝对颗粒物质的生物学反应，腐殖酸的颗粒相和溶解相 Cd 的生物积累特征明显不同。在 Cd 浓度为 140mg/kg 时，与腐殖酸混合物结合的 Cd 的积累主要归因于腐殖酸的溶解相。与颗粒相相比，与腐殖酸溶解相结合的 Cd 可能具有更高的生物利用度。
