Possible human health risk of selected heavy metals mobility from municipal waste compost amended agricultural soil

Abstract

Use of organic compost in soil amendment in agricultural practice may tend to transfer heavy metals and can be a health concern. This study aims to investigate the possible mobilization of selected heavy metals from municipal compost amended soil. Experimental plots (250 m 2 ) were divided into four equal portions and alternate portions were amended with municipal compost and left for 5 weeks. Soil physicochemical characteristics for compost, compost amended soil, and unamended soil were obtained by standard procedures, single extraction was obtained by diethylenetriamine penta acetic acid (DTPA) protocol, and the geochemical forms were obtained by Bureau Community of Reference (BCR) sequential extraction method. The extracts were analyzed using Atomic Absorption Spectrophotometer (Buck Scientific Model 210). In this study, the amendment of soil with compost resulted in significant changes in various physico-chemical properties, with notable percentage increases: pH (16.72%), electrical conductivity (EC, 1509.63%), organic carbon (OC, 100.24%), organic matter (OM, 24.43%), organic nitrogen (ON, 24.41%), potassium (K, 1950.63%), sodium (Na, 325.03%), calcium (Ca, 67.93%), and magnesium (Mg, 112.92%). Although, the concentrations of metals were marginally altered by amendments, the study has revealed soil amendment with organic compost a potential source of heavy metals in diet.