On the comparative expense of light derived from different sources, and on the use of chlorine as an indication of the illuminating power of coal gas

Abstract

Based on 1186 published studies, the first national-scale assessment of cadmium (Cd) contamination in agricultural soils across China was conducted. Cd concentrations, temporal and spatial variations, and ecological and health risks resulted from Cd exposure were analyzed. A small part of sampling sites with Cd concentration surpass the screening value and the control value (GB15618-2018), respectively. Soil Cd concentrations in South China were higher than other regions. Ecological risks resulting from Cd contamination were low. Soil Cd concentrations accumulated gradually from 1981 to 2016. Cd mainly came from anthropogenic activities, such as mining, smelting, sewage irrigation, and fertilization. Linear correlations were observed between application amounts of fertilizers and Cd concentrations in soil, indicating that the application of nitrogen, phosphorus, potassium, and compound fertilizers is an important contributor of Cd in soils. This study details the overall Cd contamination status of agricultural soils in China, thus can provide insights for policymakers regarding contamination prevention measures.