Assessment of Cadmium accumulation in rice in the Red river delta due to polluted irrigation water

Abstract

     The study was conducted on agricultural cultivation land in the Red River Delta with irrigation water from the North Hung Hai irrigation system with an average Cd concentration of 4 consecutive crops (from May 2019 to May 2021) of 0.039 ppm. Under normal farming conditions, samples including soils, plant and grains were collected according to the 3 growth periods of rice to analyse the Cd content. The results indicated that the Cd accumulation in the roots gradually increases over of the growth life of rice plant with an increase rate from 1.1 - 1.2 times. The Cd content in plant increases rapidly over 3 periods with an average accumulation rate of 3.9 times. Experimental results in four crops showed the
uniform of the average Cd content in grains of 0.00575 ppm lower than the FAO standard (0.01 ppm). Furthermore, results of the correlation in Cd content in parts of the rice plant in the greenhouse experiment in order: the Cd content in roots > straws > seeds. This result due to rice grains take 80% of the dry matter from photosynthesis and the remaining nutrients taken from the roots and leaves. In addition, the duration of the seeding process accounts for only 25% of the life cycle of the rice plant, so that the Cd content in grains is lower than plant and roots