An exploration of an integrated stochastic-fuzzy pollution assessment for heavy metals in urban topsoil based on metal enrichment and bioaccessibility

• Published in: The Science of the total environment Vol. 644; pp. 649 - 660
• Main Authors: Li, Fei, Zhang, Jingdong, Liu, Wenchu, Liu, Jiaan, Huang, Jinhui, Zeng, Guangming
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 10.12.2018
• Subjects: Chemical fractions; Double weight system; Ecotoxicity; Enrichment; Soil toxic metal; Soil toxic metal; Enrichment; Chemical fractions; Double weight system; Ecotoxicity
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.06.366

An integrated stochastic-fuzzy pollution assessment method (ISFPAM) for soil heavy metal was established based on geo-accumulation index (Igeo), stochastic-fuzzy theory and double weight system under synthetical consideration of metal ecotoxicity and bioaccessibility. The pollution characteristics of the topsoil heavy metals (Cu, Zn, Cd, Pb and Cr) in Xiangjiang New District were evaluated by the widely-used Single factor index (SF), Nemerow index (NI), Igeo, Potential ecological index (PERI), Risk assessment code (RAC) and the ISFPAM. The results of SF, NI, Igeo, RI and RAC of the studied metals revealed the following orders: Cd > Zn > Cr > Cu > Pb, Cd > Zn > Pb > Cr > Cu, Cd > Cr > Cu > Zn > Pb, Cd > Cu > Pb > Cr > Zn, and Cd > Pb > Cr > Zn > Cu, respectively. The different pollution assessment methods outputted the differentiated conclusions to some extent except the judgment for Cd. Results based on ISFPAM indicated that metal pollution degrees decreased in the order of Cd (5.91, Grade 6) > Cu (2.81, Grade 3) > Pb (2.66, Grade 3) > Cr (1.58, Grade 2) > Zn (0.69, Grade 1). By detailed comparison analysis, the double weight system and stochastic-fuzzy theory made ISFPAM better resolving ability to find out priority heavy metals and areas with relatively higher enrichment, ecotoxicity and bioaccessibility under efficient parameter uncertainty control. Cd, Cu and Pb were regarded as the priority control metals, especially Cd. Simultaneously, the reliabilities of heavy metal pollution corresponding to adjacent pollution grades were quite close in some sites, which recommend recheck for avoid misleading the decision-makers. [Display omitted] •Soil metal enrichment, ecotoxicity and bioaccessibility need integrated evaluation.•Integrated stochastic-fuzzy pollution assessment method (ISFPAM) was established.•ISFPAM integrated Igeo, stochastic-fuzzy theory and double weight system.•Cd, Cu and Pb was identified to be priority pollutants in topsoil from XND.•ISFPAM show better resolving ability compared with SF, NI, Igeo, RI and RAC.