Quantification of the sorption of organic pollutants to minerals via an improved mathematical model accounting for associations between minerals and soil organic matter

Jie Cheng; Qi Ye; Zhijiang Lu; Jiangjiang Zhang; Lingzao Zeng; Sanjai J Parikh; Wanzhu Ma; Caixian Tang; Jianming Xu; Yan He

doi:10.1016/j.envpol.2021.116991

Quantification of the sorption of organic pollutants to minerals via an improved mathematical model accounting for associations between minerals and soil organic matter

Environ Pollut. 2021 Jul 1:280:116991. doi: 10.1016/j.envpol.2021.116991. Epub 2021 Mar 23.

Authors

Jie Cheng¹, Qi Ye¹, Zhijiang Lu¹, Jiangjiang Zhang¹, Lingzao Zeng¹, Sanjai J Parikh², Wanzhu Ma³, Caixian Tang⁴, Jianming Xu¹, Yan He⁵

Affiliations

¹ Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou, 310058, China.
² Department of Land, Air and Water Resources, University of California - Davis, Davis, CA, USA.
³ Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture and Rural Affairs of China, Hangzhou, 310021, China.
⁴ Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria, 3086, Australia.
⁵ Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou, 310058, China. Electronic address: yhe2006@zju.edu.cn.

PMID: 33845409
DOI: 10.1016/j.envpol.2021.116991

Abstract

The retention of organic pollutant (OP) in soils is commonly attributed to interactions with soil organic matter (SOM), perhaps overlooking substantial involvement of soil minerals. In this study, 36 soil samples with far-ranging ratios of clay to organic carbon were used to examine contribution of minerals on soil sorption of pentachlorophenol (PCP) and phenanthrene (PHE). Sorption isotherms (n = 216) were fit individually using three typical sorption models, with the most fitted K_d values screened out for quantification of the net mineral contribution to total sorption via development of mathematical model accounting for associations between minerals and SOM. Two mineral-relevant parameters [adsorption distribution coefficient (K_min) and mineral contribution index (MCI)] were simultaneously defined. Previously reported soil sorption data of PCP, PHE and butachlor (13, 12 and 46, respectively) were also extracted and included to improve the credibility of mathematic model. The average MCI values were calculated as 0.421, 0.405 and 0.512 in PCP, PHE and butachlor treated soils, respectively, very close to or even over than the minerals dominant critical value (0.5). This suggested the significant, or even predominant, contribution of minerals - as compared to SOM. Significant dependence of MCI with four conventional parameters of soil property further offered the possibility to roughly evaluate mineral contributions based on estimated threshold values of soil property parameters (especially TOC). This study provides an accessible approach for predicting the contribution of minerals in soil OP retention, especially highlighting their predominant roles vs. SOM in regulating OP removal in most of subsurface soil or contaminated brownfields where organic carbon content of soil was very low, that was not like what previously believed.

Keywords: Adsorption distribution coefficient (); Mineral contribution index (MCI); Minerals; Organic pollutant; Organic-soil equilibrium equation.

MeSH terms

Adsorption
Environmental Pollutants*
Minerals
Models, Theoretical
Soil
Soil Pollutants* / analysis

Substances

Environmental Pollutants
Minerals
Soil
Soil Pollutants