甘肃徽县铅锌污染农业区冬季土壤纤毛虫群落特征

Community Characteristics of Soil Ciliates in Lead-Zinc-Contaminated Agricultural Areas of Huixian County, Gansu Province in Winter

2006年10月至2008年5月,用活体观察和固定染色方法对甘肃省徽县铅锌污染农业区土壤中纤毛虫冬季的群落特征进行了研究。在5个样点中共鉴定到土壤纤毛虫75种(包括9个未定名种和3个国内新记录种),隶属于3纲、11目、30科、41属;对照1、对照2、厂区、县城和牟坝各样点的土壤中分别有纤毛虫42、39、17、16和28种;对照样点与受污染较重的厂区、县城和牟坝土壤中纤毛虫群落相似性系数为极不相似(q=0.14、0.22、0.27之间);各样点的物种多样性指数分别为4.76、4.28、2.15、2.05和3.28;各样点的铅含量分别为211、182、490、427和434mg·kg-1,锌含量分别为48.4、46.8、1194、166和392mg·kg-1。结果表明,铅锌污染对农业土壤纤毛虫群落有很大影响,主要体现在群落结构趋于简单化,物种多样性明显下降。

The community characteristics of soil ciliates in Lead-zinc-contaminated agricultural areas of Huixian County, Gansu Province in winter were studied from October 2006 to May 2008.The farmlands of Xinsicun and Mubacun villages around a Lead-zinc smelter in Shuiyangxiang township were selected as the sampling sites while the farmland and hillslopes which are distant from pollution sources but have a similar soil environment were selected as the control sampling sites. The methods and results based on the study were summarized as follows： Sampling sites introduction： （1）Control site 1 lies in a hillslope （major crops there：wheat, maize and soybean） which is about 4 kilometers away from the smeher.（2）Control Site 2 is a scenic spot located on a hill about 3 kilometers far from the county town.（3）Xiancheng site is a farmland-based hillslope located on the banks of the Shuiyangjiang River to the southwest of the county town. （4）Changqu site, a core Lead-zinc-contaminated area lies in a farmland（major crops there：wheat, maize, soybean and vegetables） next to the Lead-zinc smelter about 2 kilometers far from the county town.（5）Muba site is located in a farmland（major crops：wheat, maize and soybean） about 3 kilometers away from the core Lead-zinc-contaminated area. The quincunx-sampling method was adopted in an area about 400 m^2. 30 mL stainless steel cylinders were used to collect 20 soil samples which were about 3 000 g after blending and then were divided into 2 shares used respectively for the cultivation of ciliates and determination of the content of heavy metals（ Pb, Zn） in the soil. The soil temperature, humidity and pH were also measured while sampling. Research method：The ＂non-flooded petri dish method＂ was used for the continuous cuhivation of soil ciliates, after which the species identification was conducted with an optical microscope and the respective abundances were recorded as well on the 2^nd, 4^th, 7^th, 11^th, 20^th and 28^th day. The identification techniques include in vivo observation and fixation-staining as well as species identification and taxonomy references[21]-[32]. The determination of the concentrations of lead and zinc in the various samples was measured using an atomic absorption spectrophotometer（AAnaLyHt 400） （made by a shanghai branch of American TE Company） by the Upstream Yellow River Water Environment Monitoring Center.Research results ： The study results were summarized as follows ： 75 species were totally identified in 5 sampling sites, including 9 unnamed species and 3 new records of soil ciliates in China, belonging to 3 classes, 11 orders, 30 families and 41 genera. There were 42, 39 species respectively distributed in soil sites of Controls 1 and 2, and 17, 16, 28 species respectively distributed in pollution soil sites of Changqu, Xiancheng and Muba.The soil ciliate communities in the control sites and pollution sites were quite dissimilar（q=0.14, 0.22, 0.27 ）. The species diversity index was respectively 4.76, 4.28, 2.15, 2.05 and 3.28 in sampling sites of Controls 1 and 2, Changqu, Xiancheng and Muba. Their lead coneentrations were respectively 211, 182, 490, 427 and 434 mg·kg^-1 in the 5 sampling sites and the zinc concentrations were respectively 48.4, 46.8, 1 194, 166 and 392 mg·kg^-1. The results show that community structure of soil ciliates have been influenced greatly by lead and zinc pollution, which indicates in the simplification of community structure and significant deeline in species diversity.