花生对DDT的吸收积累

采用盆栽试验,通过向土壤中添加DDT设置3个浓度处理(T1,295 ng g-1;T2,3723 ng g-1;T3,6109 ng g-1)和1个对照(CK,31 ng g-1),研究花生(Arachis hypogaea)对DDT的吸收积累。花生果实成熟后将植株分成根、茎、果壳和果仁四部分,GC-ECD测定各部位中的DDT浓度。结果表明,在T2和T3处理中,花生果仁中的DDT含量高达200 ng g-1左右,超过100 ng g-1的WHO/FAO最大残留限量标准。虽然在CK和T1中,花生的果仁没有超标,但是,果壳和茎中,特别是根中DDT的高浓度值得关注。根部的总量最大,果仁中的总量最小,根部是DDT吸收积累的最主要部位。花生根部和茎部较高的生物蓄积系数暗示着花生对DDT具有较强的吸收积累能力。此外,研究显示花生果仁中高的含油量可能有助于亲脂性DDT的吸收积累。

UPTAKE AND ACCUMULATION OF DDT BY PEANUT (ARACHIS HYPOGAEA)

A pot experiment was conducted with three treatments (T1,295 ng g^-1;T2,3 723 ng g^-1;T3,6 109 ng g^-1 in concentration of DDT) and one control (CK,31 ng g^-1),When peanuts were mature whole peanut (Arachis hypogaea) plants were harvested and divided into four parts,roots,stems,husks and kernels.Concentrations of DDT in these parts were determined separately by GC ECD.Results show that the concentration of DDT in the kernels was about 200 ng g^-1 in T2 and T3,exceeding the maximum residue limit for DDT residue (100 ng g^-1) set by WHO/FAO.In general,the concentration of DDT in peanut ker nels is not likely to exceed the maximum residue limit in current environment,but the concentrat ions of DDT in the husks and stems,especially in the roots,of the plants were rather high,which causes more concerns.The total amount of ΣDDT in the roots was the highest,indicat ing the roots are the dominating part of the plant that takes up and accumulates DDT.Fairly high bioaccu mulation factors of the roots and the stems suggest the peanut plant is great in capacity of absorbing and accumulating DDT.Fur thermore,the results suggest that the high oil content in peanut kernels might facilitate the uptake and accumulat ion of lipophilic DDT.