Identification of Soil Heavy Metal Sources in a Large-Scale Area Affected by Industry

Abstract

Heavy metals (HMs) in soil are some of the most serious pollutants due to their toxicity and nonbiodegradability. Especially across large-scale areas affected by industry, the complexity of pollution sources has attracted extensive attention. In this study, an approach based on zoning to analyze the sources of heavy metals in soil was proposed. Qualitative identification of pollution sources and quantification of their contributions to heavy metals in soil are key approaches in the prevention and control of heavy metal pollution. The concentrations of five HMs (Cd, Hg, As, Pb and Cr) in the surface soil of the Chenzhou industrial impact area were the research objects. Multiple methods were used for source identification, including positive matrix factorization (PMF) analysis combined with multiple other analyses, including random forest modeling, the geo-accumulation index method and hot spot analysis. The results showed that the average concentrations of the five heavy metals were 9.46, 2.36, 2.22, 3.27 and 1.05 times the background values in Hunan soil, respectively. Cd was associated with moderately to strongly polluted conditions, Hg, As and Pb were associated with unpolluted to moderately polluted conditions and Cr was associated with practically unpolluted conditions. The mining industry was the most significant anthropogenic factor affecting the content of Cd, Pb and As in the whole area, with contribution rates of 87.7%, 88.5% and 62.5%, respectively, and the main influence area was within 5 km from the mining site. In addition, we conducted hot spot analysis on key polluting enterprises and identified hot spots, cold spots, and areas insignificantly affected by enterprises, used this information as the basis for zoning treatment and discussed the sources of heavy metals in the three subregions. The results showed that Cd originated mainly from agricultural activities, with a contribution rate of 63.6%, in zone 3. As originated mainly from sewage irrigation, with a contribution rate of 65.0%, in zone 2, and the main influence area was within 800 m from the river. This element originated mainly from soil parent materials, with a contribution rate of 69.7%, in zone 3. Pb mainly originated from traffic emissions, with a contribution rate of 72.8%, in zone 3, and the main influence area was within 500 m from the traffic trunk line. Hg was mainly derived from soil parent materials with a contribution rate of 92.1% in zone 1, from agricultural activities with a contribution rate of 77.5% in zone 2, and from a mixture of natural and agricultural sources with a contribution rate of 74.2% in zone 3. Cr was mainly derived from the soil parent materials in the whole area, with a contribution rate of 90.7%. The study showed that in large-scale industrial influence areas, the results of heavy metal source analysis can become more accurate and detailed by incorporating regional treatment, and more reasonable suggestions can be provided for regional enterprise management and soil pollution control decision making.

Heavy Metal(loid)s Pollution of Agricultural Soils and Health Risk Assessment of Consuming Soybean and Wheat in a Typical Non-Ferrous Metal Mine Area in Northeast China

“…Lower soil Cd in the present study than that in Shanxi Province, China and Central Greece can be observed [1], which might result from long-term agricultural activities, such as the application of agrochemicals and fertilizer in Shanxi Province and Central Greece [33]. Cu was more obviously accumulated in some sites (DM soils, T1 soil, and KQ soil) than in other studies [1,32], but concentrations of Pb in DM, TM, and DDS soils were lower than that in Hunan Province (97 mg/kg) [31]. Se, Mo, and Mn are not listed in the soil quality standard of China, but their concentrations were comparable to the background values of soil (except Se in KQ soil), indicating a lower environmental risk.…”

“…Notes:1 Coefficient variation, 2 Date from reference[1],3 Date from reference[31],4 Date from reference[32],5 Background values of soil heavy metal(loid)s in Heilongjiang province[22],6 Date from reference[30].…”

Contents and spatial distribution patterns of heavy metals in the hinterland of the Tengger Desert, China

“…The reason for the high content of heavy metals can be attributed to human activities. At the same time, researchers analyzed the spatial distribution characteristics, sources, and input pathways of heavy metals in soils based on principal component analysis (PCA) (Ustaoglu and Islam, 2020), positive matrix decomposition (PMF) (Xu et al, 2021), cluster analysis (CA) (Kelepertzis, 2014), geographic information systems (GIS) (Anaman et al, 2022), indicators such as contamination factors (CF) (Marrugo-Negrete et al, 2017;Baltas et al, 2020), geologic enrichment index (I-geo) (Islam et al, 2015;Adimalla, 2020), and potential ecological risk (PERI) (Maanan et al, 2015;Kusin et al, 2018). The application of those integrated methods can help to identify the sources and transport routes of heavy metals under different land-use patterns, and provide more reliable data for ecological risk assessments.…”

Transformation of the chemical properties of soils in the zone of influence of the asphalt concrete plant

“…But the most dangerous factor for plants and other living organisms is the degree of accessibility, which is determined by the mobility of chemical elements [6]. Heavy metals (HM) in soil are one of the most serious pollutants due to their toxicity and nonbiodegradability [7]. Heavy metals are involved in biological circulation, are transferred along food chains and cause a number of negative consequences.…”