Accumulation of heavy metals in grape fruit, leaves, soil and water: A study of influential factors and evaluating ecological risks in Jaffna, Sri Lanka

Abstract

Heavy metals are environmental pollutants which threatens human health and natural ecosystem. These affect the quality of soil and water and it can be transferred to human body while consuming agricultural crops and drinking water. Intense cultivation has been resulted in accumulation of heavy metals and trace elements due to the excess use of agrochemical substances for obtaining better yield in Sri Lanka. The usage of agrochemicals leads to loss of originality of soil, water and food with bioaccumulation. This study aimed to find out the effect of fertilizer and pesticides on grape yard, water, leaves and grape fruits. The samples from water, soil and plant materials were collected in intensive cultivated areas in Jaffna and tested for heavy metal contamination. The concentrations of Zn, Ni, Cu, As, Pb, Mg and Al in soils varied from 7.5 to 61.4, 0.4–48.3, 3.6–20.3, 0.56–3.56, 3.1–11.6, 108–957, 0.1–3.6 mgkg−1 respectively. Assessed ecological risk indicated that soil was moderately contaminated by Pb and Cu. While considering toxic effect of heavy metals in soil was classified as the moderate degree based on their intensities. The content of metals in fruit samples varied such as Zn from 0.2 to 1.9 mgkg−1, Ni from 0.05 to 0.2 mgkg−1, Cu from 0.3 to 1.3 mgkg−1, As and Pb less than 0.05 mgkg−1. The concentrations of tested metals were found in negligible amount in water. Most of the accumulated metals are mainly concentrated in the leaves of the grape tree than in the fruit. The findings of this study can be applied in the adoption of measures to reduce the usage of metals that generate toxicological effect in the grape cultivated ecosystem of Northern part of Sri Lanka.