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利用颗粒物悬浮系统研究了沉积物中Cd的特定赋存形态(如氢氧化铁结合态、氢氧化铝结合态、二氧化锰结合态)对其在文蛤体内富集速率的影响.结果表明,结合于沉积物中不同组分Cd的生物有效性存在明显差异.在Cd浓度为70 mg/kg时,22 d富集实验中氢氧化铁结合态和氢氧化铝结合态Cd在文蛤体内均没有明显的积累,而二氧化锰结合态Cd在文蛤体内有明显的富集,其富集速率为(0.009 4±0.001 0)μg/(g.d)(r2=0.853 9,p<0.000 1).在Cd浓度为140 mg/kg时,氢氧化铁结合态Cd仍然无法被文蛤吸收,氢氧化铝和二氧化锰结合态Cd则可以被文蛤富集,其富集速率分别为(0.016 6±0.001 7)μg/(g.d)和(0.024 8±0.001 7)μg/(g.d).不同赋存形态Cd的生物有效性表现为:Cd-MnO2>Cd-Al(OH)3>Cd-Fe(OH)3.对于不同赋存形态的Cd,吸收效率(AE)和摄食率(IR)的差异导致了其生物有效性的不同.
The effects of specific speciation of Cd (such as iron hydroxide bound, aluminum hydroxide bound and manganese dioxide bound) on the enrichment rate of clam in the sediments were studied by the particle suspension system.The results showed that the binding There was a significant difference in the bioavailability of different components of Cd in the sediments.When Cd concentration was 70 mg / kg, there were no significant differences in the iron-hydroxide bound and aluminum hydroxide bound Cd during the 22-day enrichment , While Mn (superscript 2 +) bound Cd was obviously enriched in the clam, the enrichment rate was 0.009 4 ± 0.001 0 μg / (gd) (r2 = 0.853 9, p <0.000 1) At the concentration of 140 mg / kg, the ferric hydroxide bound Cd was still unable to be absorbed by the clams. Aluminum hydroxide and manganese dioxide bound Cd could be enriched by clam, the enrichment rates were (0.016 6 ± 0.001 7) μg / (gd) and (0.024 8 ± 0.001 7) μg / (gd), respectively.The bioavailability of Cd with different occurrences was: Cd-MnO2> Cd-Al (OH) 3> Cd-Fe Differences in absorption efficiency (AE) and ingestion rate (IR) led to differences in their bioavailability for different cadmium species.