河西走廊及兰州地区土壤中典型有机氯农药残留研究

Typical Organochlorine Pesticides Residues in the Topsoils of Hexi Corridor and Lanzhou Area, China

应用Agilent7890-5975CGC-MSD对甘肃省河西走廊及兰州地区17个表层土壤样品中六六六（HCHs）和滴滴涕（DDTs）的残留水平进行分析,并对其来源进行初步解析。研究结果表明：研究区土壤中DDTs残留范围为0.22~53.69ng·g-1,平均值为8.58ng·g-1;HCHs残留范围为0.07~9.16ng·g-1,平均值为1.32ng·g-1;DDTs的残留较HCHs占优势,约占二者总残留量的87%。（DDE＋DDD）/DDT比值介于0.12~0.48之间,平均值为0.27,o,p′-DDT/p,p′-DDT比值在0.11~0.79之间,平均值为0.34,表明研究区土壤中的DDTs主要来源于工业源DDTs残留。α-HCH/γ-HCH介于0.64~15.5间,平均值为3.19,可推断研究区近期内不存在HCHs的使用,土壤中的HCHs残留主要来源于历史上工业HCHs和林丹的共同输入。与国内外其他地区土壤相比,该地区HCHs和DDTs的残留量处于较低水平;依照土壤环境质量标准（GB15618—1995）的要求,研究区各采样点土壤环境处于相对安全的状态。

Organochlorine pesticides （OCPs） are a group of persistent organic pollutants （POPs） because of their high toxicity, persistence and bioaccumulation. So far few data are available on the Northwest of China. In this paper, 17 topsoil samples were collected in Hexi corridor and Lanzhou area of Gansu Province, meanwhile, the HCHs and DDTs residues in these samples were determinated using Agilent 7890- 5975C GC-MSD. In addition, the sources of HCHs and DDTs were appointed. The study results showed that the OCPs residue levels were in the range of 0.22-53.69 ng·g-1 for DDTs and 0.07-9.16 ng·g-1 for HCHs, respectively, in the topsoils of both Hexi corridor and Lanzhou re- gions. And the average content of OCPs was 8.58 ng·g-1 for DDTs and 1.32 ng·g-1 for HCHs. Moreover, the results also indicated that DDTs was dominant in both topsoils of areas, accounting for 87% of the total residues of HCHs and DDTs. Furthermore, the DDT/（DDE＋DDD） ratio ranged from 0.12 to 0.48, with a mean value of 0.27, and the o,p＇-DDT/p,p＇-DDT ratios were from 0.11 to 0.79 with a mean value of 0.34, which denoted that DDTs residues were mainly from technical DDTs, while a-HCH/y-HCH ratio ranged from 0.64 to 15.5, with a mean val- ue of 3.19, indicated that HCHs residues were mainly from both histor/cal application of technical HCHs and Lindane in the study area. Compared with those in other regions and China＇s Soil Environment Quality Standard（GB 15618--1995 ）, the topsoil burden of HCHs and DDTs in Hexi corridor and Lanzhou area was lower, which instructed that the soil environment in the study area was in a relatively safe state.