Study On Soil Heavy Metal Pollution Pattern In Small Watershed Of Black Soil Region

Land plays a vital role in human production and life,and it is the foundation and fundamental guarantee for the development and progress of human society.In recent years,with the rapid development of the economy at the same time is the same rapid increase in the population,followed by pressure to force us to a deeper degree of land resources,human resources in the development and utilization of land resources in the process of development and utilization,Heavy metal pollution and spatial distribution of soil will be changed in different degrees.Rational utilization,regional eco-environmental security and stability,and land sustainable use in the study of huge obstacles.The small watershed in the black soil area is located in the southwest of Heilongjiang Province,in the area of the combination of urban and rural areas between Harbin and the surrounding countryside.In recent years,urbanization,industrialization and agricultural intensification have developed rapidly.Urban expansion and man-made factors pose a serious threat to soil quality.It is necessary for sustainable development of land pollution in watershed soil,spatial pattern,and the impact of landscape pattern on soil heavy metal pollution from a macro perspective.It has important reference significance to guarantee the quality of cultivated land and improve the ecological environment of land.The Haigou River watershed located in the typical black soil area of Northeast China was chosen as the research area.The research background was to protect the soil resources,improve the quality of cultivated land and improve the ecological environment of land,and applied geostatistical analysis and classical statistical theory as the research basis.Based on the "3s" technique and the corresponding spatial interpolation method,the spatial distribution pattern,landscape pattern characteristics and influencing factors of heavy metal Cu,Zn,Hg,As,Pb and Ni pollution in watershed soil were studied.The main conclusions are as follows:(1)Spatial distribution pattern of heavy metals in soil.The spatial distribution characteristics of Cu,Zn,Hg,As and Ni elements were that the high content areas were mainly concentrated in the northwest region,and decreased from the northwest to the southeast,and the contents of Cu,Cu and Ni decreased from northwest to southeast.The spatial distribution characteristics of the content of Pb elements are gradually increasing from the middle region to the east-west direction.The spatial distribution of the six soils polluted by heavy metal elements was different.The distribution of high and low content areas of Cu,Pb and Ni elements showed two grades and thedifference was obvious.The majority of the regions were low content regions,and there was a significant difference in the distribution of high content regions and low content regions of heavy metal elements in the six soils.The regions with high content of Hg elements are more dispersed and the regions with medium content are more.It can be seen from the spatial distribution pattern of potential ecological risk that the high risk area is concentrated in the northwest of the study area,and the whole pollution degree spreads from the west to the east from the high to the low to the east,which is related to the Cu,.The distribution of small area heavy pollution area of Hg and Ni elements is similar.The potential eco-polluted landscape category of the whole study area is mainly medium content area.(2)Landscape pattern of heavy metal pollution in soil.The landscape of the study area is high in concentration,complete in landscape and high in connectivity.The edge length of patch types in the landscape is more uniform.A few large patches are dominant in the landscape,and the same type of patches are highly connected with each other,and the dispersion of each other is small.The fragmentation degree of Pb and Ni landscape was higher,that of Cu and Hg landscape was medium,and that of Zn and As landscape was lower than that of Zn and As landscape.From the view of landscape index of type level,the patch scale index(PLAND,AREA_MN,LPI)first increased and then decreased with the increase of pollution level,but the region with lower content was lower.And medium content area is dominant;The aggregation degree of As decreased with the increase of pollution level.The aggregation degree of low content area of Cu,As and Ni landscape was the highest,and that of low content area of Zn and Hg landscape was the highest.The aggregation degree of potentially polluted landscape is generally higher than that of other element polluted landscape types.(3)Influencing factors of soil heavy metal pollution pattern.The effects of land use on the pattern of soil heavy metal pollution were studied.The results showed that the patch of land use type was relatively concentrated,the spatial connectivity between patches was higher,and the more complex patch shape was,the greater the potential ecological risk of soil heavy metal was.The lower the cleanliness of the land.The effects of topography and landform on the pollution pattern of heavy metals in soil show that the pollution degree of heavy metals in soil decreases with the increase of elevation and slope.