Source Investigations, Quality Indexing of Vegetable Farmland and Human Health Risk Implications

Abstract

Climate changes effects, food security and self-sufficiency targets in densely populated countries like Bangladesh forced excessive human activities on vegetable farmland, and heavy metal contamination may result. An analysis of three toxic heavy metals, such as lead (Pb), cadmium (Cd), and chromium (Cr), was conducted to determine their source and associated health risks in vegetables, taking into account source pathways, fertilizers/pesticides and soil, using 12 sampling points at two different locations in two different Flam-Atomic Absorption Spectrometry (F-AAS) and Graphite Furnace-AAS (GF-AAS) modes. In soil and fertilizers/pesticides, the mean concentration of heavy metals declined in the same order of Cr > Pb > Cd. For vegetables, the mean concentration decreased in the order of Pb > Cr > Cd with some extra quantity of Pb compared with an allowable limit of World Health Organization (WHO) predicting industrial and fertilizer usage impact on location B. For both locations, the quality indexing of soil projected low levels of contamination with insignificant ecological risks. The toxic metal transfer to vegetables followed the order Cd > Pb > Cr, the same for both locations but higher at location B. However, the toxic metals uptake through vegetables was much less than maximum tolerable daily intake. The human health risks arising from harmful metals exposure at both locations were ineffective (< 1) in evaluating non-carcinogenic risk patterns through target hazard quotient (THQ), total THQ and hazard index (HI). Again considering probable carcinogenic risk patterns, vegetable consumption with studied exposure levels of toxic metals will be significant (between 1.0E-04 to 1.0E-04). Overall, location B is a little bit more vulnerable than A by considering the non-carcinogenic and carcinogenic model and related intervention and protective measures are needed to be taken.