Impacts from Land Use Pattern on Spatial Distribution of Cultivated Soil Heavy Metal Pollution in Typical Rural-Urban Fringe of Northeast China

Abstract

Under rapid urban sprawl in Northeast China, land conversions are not only encroaching on the quantity of cultivated lands, but also posing a great threat to black soil conservation and food security. This study’s aim is to explore the spatial relationship between comprehensive cultivated soil heavy metal pollution and peri-urban land use patterns in the black soil region. We applied spatial lag regression to analyze the relationship between PLI (pollution load index) and influencing factors of land use by taking suburban cultivated land of Changchun Kuancheng District as an empirical case. The results indicate the following: (1) Similar spatial distribution characteristics are detected between Pb, Cu, and Zn, between Cr and Ni, and between Hg and Cd. The Yitong River catchment in the central region, and the residential community of Lanjia County in the west, are the main hotspots for eight heavy metals and PLI. Beihu Wetland Park, with a larger-area distribution of ecological land in the southeast, has low level for both heavy metal concentrations and PLI values. Spatial distribution characteristics of cultivated heavy metals are related to types of surrounding land use and industry; (2) Spatial lag regression has a better fit for PLI than the ordinary least squares regression. The regression results indicate the inverse relationship between heavy metal pollution degree and distance from long-standing residential land and surface water. Following rapid urban land expansion and a longer accumulation period, residential land sprawl is going to threaten cultivated land with heavy metal pollution in the suburban black soil region, and cultivated land irrigated with urban river water in the suburbs will have a higher tendency for heavy metal pollution.

Analysis of Heavy Metal Sources in the Soil of Riverbanks Across an Urbanization Gradient

“…We analyzed the main factors influencing the heavy metals, based on the existing studies [ 6 , 22 , 23 , 24 , 25 ]. There were four categories of factors from five different sources.…”

Application of Time-Lapse Ion Exchange Resin Sachets (TIERS) for Detecting Illegal Effluent Discharge in Mixed Industrial and Agricultural Areas, Taiwan

“…Anthropogenic sources generally have higher reactive fraction than geogenic metal forms [70]. Different land use types [76] and spatial variations in land use pattern [77,78] have been reported to influence heavy metal contamination in soils. Kriging interpolation and spatial regression models are broadly applied to analyze the relationship between metal concentrations and possible influencing factors, as the soil heavy metal concentrations are related to their neighbors and potential sources rather than being independent of each other [78][79][80][81].…”

“…Kriging interpolation and spatial regression models are broadly applied to analyze the relationship between metal concentrations and possible influencing factors, as the soil heavy metal concentrations are related to their neighbors and potential sources rather than being independent of each other [78][79][80][81]. However, the evidence of location accuracy from potential sources is still insufficient [78]. Therefore, we were able to accurately identify the location of direct discharge sources and the amount of discharged metal concentrations to reflect the metal pollution in water under the impacts of effluent discharge from the factories.…”

Does Fallowing Cultivated Land Threaten Food Security? Empirical Evidence from Chinese Pilot Provinces

“…Ecological problems resulting from urban sprawl and polluting industrialization are another issue. Considerable heavy metal contaminant [8], water and soil loss [9], desertification [10], and so on have occurred. Thus, cultivated land in China is unsustainable and needs protective measures.…”