Risk Assessment of Some Selected Vegetables Grown in Metal Contaminated Soil Supplements
2016
Pal, Raikamal | Kundu, Rita
Application of municipal solid waste and sewage sludge to supplement soil is an age-old agronomic practice due to its rich organic contents. These soil-supplements also contain significant amount of non-essential heavy metals, posing threat to crop yield and human health. The present study aims to compare the phytotoxicity of the heavy metals and potential dietary toxicity of some selected vegetables grown in soil supplemented with municipal solid waste and sewage sludge. To assess the phytotoxicity of the supplements, plants were grown in three different sets; (1) Hoagland’s nutrient media [as control] (2) municipal solid waste and (3) sewage sludge soil mix. To study the phytotoxic markers, photosynthetic pigments, proline, protein content and antioxidant enzyme activities were measured and metal content of the vegetables were measured to estimate the potential dietary toxicity. It was observed from the study that vegetables grown in supplemented soils showed reduced chlorophyll and protein content while carotenoid, proline and antioxidative enzymes showed enhanced activity. In both the supplemented soil, it was observed that cadmium was present above the maximum allowable limits, amount of lead was marginal and that of chromium was below the level. It was observed that the two leafy vegetables, i.e., Lagenaria sp. and Cucurbita sp. accumulated more lead in their aerial parts, Lagenaria grown in sewage sludge supplemented soil also accumulated significant amount of cadmium in the aerial parts. Edible parts of Raphanus and maize grains also accumulated considerable amount of cadmium, which were above the value of daily tolerable limits.
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