Assessing soil cadmium quality standards for different land use types: A global synthesis

Abstract

The contamination of cadmium (Cd) in soil has become an increasingly serious issue worldwide, presenting significant risks to human health, crop safety, and ecosystems. Despite its importance, there is a lack of standardized soil threshold values for use in regulating exposure to Cd-contaminated surface soil. By synthesizing soil environmental standards for Cd from 61 countries and 75 regions, this study analyzed and categorized these standards by land use types. The distribution of Cd quality standards among various countries was determined, based on available data primarily from the United States, Canada, Europe, Australia, and China. The established soil Cd quality standards were also determined for different land types, including lands for agricultural, residential, industrial, construction, commercial uses, and parks/green spaces. Using the ecological environment criteria - species sensitivity distribution (ECC-SSD) model, Cd levels were analyzed across different land use types, and it was determined that a log-logistic distribution was the best fitted model. Our findings indicated that soil Cd quality standards ranged from 0.11 to 5.20 mg/kg for agricultural land, 1.25 to 171.51 mg/kg for residential land, and 2.58 to 1845.26 mg/kg for industrial land, all within the 5-95 % percentile range. The 5 % hazard concentration (HC5) value was recommended as the latest national quality standards for each land type. This comprehensive assessment of global soil Cd quality standards provides valuable insight for decision-makers tasked with effectively managing and mitigating Cd pollution in soil.

Keywords: Cadmium; Land type; Soil quality standard; Species sensitivity distribution (SSD).