Heavy Metals in Agricultural Soil and Their Impacts on Rice Production and Human Health: A Review

Rice is one of the most important sources of carbohydrates for humans. The non-degradable and carcinogenic characteristics of heavy metals are the main concerns. Intensive use of farm inputs, industrialization and urbanization cause heavy metals accumulation in the soil, water, and rice grains. This review aimed to assess heavy metals pollution in agricultural soil and their transformation into rice grains. It collected information from different journals, websites, and published reports on heavy metals in soils, water, and accumulated rice grains in the last 13 years. The analysis results illustrated that the amount of heavy metal in the soil and rice of different rice-producing countries was higher than the permissible limits of the WHO, United Kingdom, Tianjin, and European Union standards. The accumulation of heavy metals in agricultural land has become a threat to humans as well as the environment. Reports showed that the higher concentrations of heavy metals in rice grains may cause heart disease, diabetes, possibly stroke, liver changes, hearing changes, changes in blood pressure, diarrhea, flushing of the face, etc. in humans. Regular monitoring and strict regulations of industrial discharge and chemical fertilizer should be recommended for the safety of soil and public health in rice-producing countries.