Department of Applied Chemistry, China Agricultural University, Beijing, People's Republic of China.
Chirality. 2012 Aug;24(8):615-20. doi: 10.1002/chir.22034. Epub 2012 Jun 6.
The enantioselective bioaccumulation and elimination behaviors of α-hexachlorocyclohexane (α-HCH) enantiomers in earthworm and soil were investigated by chiral gas chromatography. Enantiomer fraction values were calculated as indicators of the enantioselectivity. The mature earthworms were exposed to 0.10 µg g(-1)(wwt) (0.14 µg g(-1)(dwt)) spiked soil continuously for the bioaccumulation, and the elimination was conducted after an enrichment period in the soil. The results showed that both the bioaccumulation and elimination processes followed monophasic kinetics, body residues of α-HCH in earthworm increased to high level at the fifth day, and enantioselectivity was found in the bioaccumulation process with the rate constant (k) of 0.80 d(-1) for (+)-α-HCH and 0.74 d(-1) for (-)-α-HCH. The half life (t(1/2)) of the enantiomers obtained in the elimination process was within one day. The bioaccumulation factors of steady state of α-HCH enantiomers were 2.82 for (+)-α-HCH and 2.75 for (-)-α-HCH. The enantiomer fractions of earthworm and soil obviously below 0.5 during uptake and elimination processes indicate significant enantioselectivity and preferential depuration of (+)-α-HCH in earthworm. However, earthworms do not have a great capacity for getting rid of α-HCH in polluted soil shown by a contradistinctive experiment.
采用手性气相色谱法研究了α-六氯环己烷（α-HCH）对映体在蚯蚓和土壤中的对映体选择性生物积累和消除行为。对映体分数值被计算为对映体选择性的指标。成熟的蚯蚓持续暴露于 0.10µg g(-1)(wwt)（0.14µg g(-1)(dwt))污染土壤中进行生物积累，然后在土壤中富集一段时间后进行消除。结果表明，生物积累和消除过程均遵循单相位动力学，蚯蚓体内α-HCH 残留量在第 5 天增加到高水平，并在生物积累过程中发现了对映体选择性，（+）-α-HCH 的速率常数（k）为 0.80 d(-1)，（-）-α-HCH 的 k 值为 0.74 d(-1)。消除过程中获得的对映体半衰期（t(1/2)）在一天内。α-HCH 对映体的稳态生物积累因子分别为 2.82（+）-α-HCH 和 2.75（-）-α-HCH。摄取和消除过程中蚯蚓和土壤的对映体分数明显低于 0.5，表明蚯蚓对（+）-α-HCH 具有明显的对映体选择性和优先降解能力。然而，蚯蚓在污染土壤中清除α-HCH 的能力并不强，这表明了一个明显的对比实验结果。
