Effect Of Heavy Metal Pollution On The Soil Fauna Community Structure

Heavy metal pollution is a serious environmental problem in china. The main sources of the heavy metal pollution include sewage irrigation, solid wastes, pesticides, fertilizers and air settlements. With the development of economy, more and more pollutants enter the environment. If the amounts of pollutants are so high that the environment can't decompose them through the abilities of self-restore, the functions of soil ecology will become maladjusted. Currently the sustainable utilization of soil resources absorbed the interest of the human being. In order to indicate the functions of soil, scientists invented the term of soil quality or soil health. Soil researchers have recently recognized the need for a reliable and systematic way to assess soil quality. A soil quality index has been developed, it include chemical properties, physical properties, soil biological properties.Fauna is an important part of soil environment. It is involved in many aspects of organic matter decomposition, partial regulation of microbial activities, nutrient cycles and crumbly structure. Depending on their diet (saprophagous, phytophagous or predation), soil fauna is closely linked both to each other and to microorganisms, plants and soil. Disturbances caused by pollutants in the soil result in both qualitative and quantitative changes in fauna, which directly affect soil function.The objectives of the present study are to investigate the fauna community in paddy soils polluted by heavy metals around a smelter factory in Fuyang County, Zhejiang province, and to examine the effect of added Cu on soil fauna community structure and ecological indicators in a greenhouse experiment. The results are summarized as follows:1 .The soil used in the pot experiment is clay loam, which is sampled from Xiasha, Hangzhou. All 1232 individuals collected could be classified into 3 phyla, 10 classes, and 16 orders. The dominant genera are Acari, Collembola and Hymenoptera, and the common genera is Heteroptera. Their frequencies are 41.07%, 17.21%, 35.23% and 2.11%, respectively. The rare genera included Corrodentia, Enchytraeidae, Isopoda, Diptera, Pauropoda, Symphyla, Araneae, Diplopoda, Lumbricidae, Nematoda, Coleoptera, Chilopda and Lepidoptera. In the collembolan community, Sinella, Onychiurus, Isotomurus are the dominance species, the frequencies are 37.26%, 31.6%,and 21.23%, respectively.2.In the agricultural ecology of Fuyang, the dominant species are Collembola and Acari. Their frequencies are 66.37% and 16.72%, respectively. Liposcelididae, Ceratopogonidae, Chironomidae, Staphylinidae, Nematoda, Enchytraeidae are common species. In the Collembolan community Folsomia and Isotomurus are the dominant species, their frequencies are 33.03% and 21.2%. The common species included Onychiurus, Desoria, Proisotoma, their frequencies are 4.3%, 1.3%, 3.21%, respectively.3.Responses of different genera of collembola to the heavy metal pollution are different. The Sinella is insensitive to Cu pollution, while Onychiurus and Isotomurus are sensitive to Cu pollution. With the increase of Cu polluted level the individuals quantities of Onychiurus and Isotomurus decreased. Some of the collembolan species such as Isotomurus and Entomobrya are sensitive to the soil heavy metal pollution, but some species such as Folsomides, Sphaeridia, Tullbergia, Sminthwidae and Lepidocyrtus are insensitive to pollution.4.The four parameters, species number, individuals abundance, diversity index and evenness index, are often used to characterize the soil fauna community structure. A negative correlation was found between Cu pollution index (total Cu concentration, Pi, and available Cu concentration) and soil fauna diversity, and between species and evenness index. The coefficient between Pi and diversity index is -0.892*. With the increase of Cu concentration, the size of MBC (microbial biomass carbon) decreased. In the agricultural ecological system, the heavy metal pollution index is significantly related to the fauna diversity index with a correlation...