Sustainability, Vol. 12, Pages 2868: As-Hg Compound Pollution: Rice Growth, Yield and Environmental Safety Limits (Sustainability)

With rapid economic and industrial development, the potentially toxic element (PTE)pollution of farmlands in China has become increasingly serious. Based on the Hakanson potentialecological risk index (RI) and national food pollutant limit standards (GB 2762-2017), the effects ofexogenous potentially toxic elements (PTEs), i.e., arsenic (As) and mercury (Hg), on rice growthwere studied. Common varieties of hybrid (YY 538, CY 84) and conventional (XS 134, JH 218) ricewere grown in pots having representative paddy soil from Zhejiang Province, China. The resultsshowed that As and Hg in soil significantly inhibited growth; however, the plant height of hybridrice was less affected. Further, there were significant correlations between concentrations of PTEsin soil and rice grains; however, hybrid rice had a stronger ability to absorb and accumulate PTEs.The comprehensive potential ecological RI of soil PTEs was 39.4–89.9, which is below the level of‘minor ecological hazard’, and the contribution rate of Hg was 79.9%–84.2%; as such, Hg posed thegreatest potential ecological risk in the study area. The ecological risk limits of As and Hg in the safeproduction of different rice varieties decreased in the order XS 134 > JH 218 > YY 538 > CY 84. Theecological risk limits of As and Hg for conventional rice were higher, and the risk limits of As andHg for hybrid rice were lower, than the limit of the soil environmental quality assessment index inthe national “Soil quality control criteria for soil pollution in agricultural land (for trialimplementation) (Trial)” (GB15618-2018). The health risk limit of soil As in the typical paddy soil ofChina decreased in the order XS 134 > JH 218 > CY 84 > YY 538. The health risk limit of Hg decreasedin the order XS 134 > JH 218 > YY 538 > CY 84. The health risk limit of As was lower, whereas therisk limit of Hg was higher, than the limit of the soil environmental quality evaluation index in thenational “Soil quality control criteria for soil pollution in agricultural land (for trial implementation)(Trial)”(GB15618-2018).