EFFECTS OF INDUSTRIAL POLLUTION AND ARSENIC CONTAMINATION ON YIELD AND METAL ACCUMULATION IN RICE GRAIN AND SOIL

Abstract

Heavy metal accumulation in rice grain appears to be a perilous problem because of application of chemical fertilizers, irrigation with arsenic (As) contaminated groundwater and use of industrial effluents. The present study was done to assess the yield and metal accumulation in Boro (BRRI dhan 28) and T. Aman (BRRI dhan 33) rice grown in industrially polluted and arsenic (As) contaminated soils. Treatments of the first pot culture experiment were T 0 (100% RDCF) and T 2 - N 75 P 15 K 30 S 10 – Control treatment; T 1 Zn 1.5 ii - N 150 P 30 (50% RDCF) + 6 ton cowdung ha ) in industrially polluted soils (S 1 – Non-polluted soil, S 2 – Polluted soil-1 and S 3 – Polluted soil-2). For the second pot experiment, different levels of irrigation (I 1 – Traditional irrigation and I 2 – Alternate wetting drying) were added along with fertilizes and manure doses (T 0 – Control; T 1 - N 150 P 30 K 60 S 20 Zn 3.0 K 60 S 20 (100% RDCF); and T 2 - N 150 P 60 K 60 S 20 Zn 3.0 ; T 3 –(N 75 P 15 K 30 S 10 Zn 1.5 (50% RDCF)+ 6 ton cowdung ha

- N 75 P 15 K 30 S 10 Zn 1.5 (50% RDCF)+ 5-ton compost/ha) were considered as treatments for As-contaminated soils. Both the pot experiments were carried out in the net-house during December 2015 to November 2016. The experiments were laid out in a 2- factor Randomized Complete Block Design (RCBD) with three replications. Results indicated that heavy metal accumulation and yield reduction were more prominent in both types of contaminated soils compared to non-contaminated (control) soils. In contaminated soils, the minimum yield of Boro and T. Aman rice were observed in T 0 S 3 and the maximum yield was in T 2 S 1 followed by T 1 S 1 treatment. However, the maximum value of Cd, Pb and Zn accumulation in the grains of both Boro and T. Aman rice was found in the T 1 S 3 treatment, while the lower values were noted in T 0

treatment. Elevated levels of heavy metals such as Zn, Cd, Pb, Cr and Ni were found in soils receiving T 1 S 3 treatment. In case of As contaminated soils, the minimum yield for both Boro and T. Aman rice was obtained in T 0 I 2 followed by T 1 , and the maximum yield was in T 4 I 1 followed by T 3 I 1 treatment. Higher accumulation of Cd and Zn in both Boro and T. Aman rice, As in Boro rice, and Pb in T. Aman rice grains were recorded in the treatment T 2 I 2 I 2 , while the lowest values were noted in T 0 treatment. The higher and lower values of the heavy metals were recorded in T 4 and T 0 I 2 treatments, respectively. In addition to pot experiments, a field survey was done in Gazipur Sadar upazila to investigate the effect of toxic heavy metals and the contaminated wastewater on the livelihood and food safety of the people living adjacent to industrial areas. The survey results revealed that industrial effluent contamination remarkably affected rice production and further it caused deterioration of grain quality leading to low market price. Nevertheless, industrial effluents are directly or indirectly causing several socioeconomic, health and environment-related problems.