Elucidating Heavy Metals Concentration and Distribution in Wild Edible Morels and the Associated Soil at Different Altitudinal Zones of Pakistan: a Health Risk Implications Study

Abstract

This study evaluates macro-nutrient (MN) and prevailing heavy metal (HM) concentrations in wild edible morels (WEM) species viz., Morchella crassipes, Morchella pulchella, and Morchella eohespera and the associated soil that were collected from different altitudinal zones (Azad Kashmir, Murree, Swat, and Skardu) of Pakistan. A special emphasis on potential health risk analysis for HM in WEM consumption was also explored. In general, MN concentration in fruiting bodies and their associated soil samples were in the following order: potassium (K) > magnesium (Mg) > calcium (Ca) > sodium (Na) and Ca > Mg > K > Na, respectively. The concentration for HM in WEM ranged between 20.0 and 78.0 mg/kg, 1.09 and 22.1 mg/kg, 2.1 and 22.1 mg/kg, 0.26 and 13.1 mg/kg, 0.43 and 9.1 mg/kg, 1.07 and 7.0 mg/kg, 1.01 and 5.4 mg/kg, and BDL and 3.1 mg/kg for zinc (Zn), copper (Cu), nickel (Ni), manganese (Mn), cobalt (Co), chromium (Cr), lead (Pb), and cadmium (Cd), respectively, and those in underlying soil samples, lowest and highest HM concentration were recorded for Zn (33.7-113.6 mg/kg), Cu (13.0-40.8 mg/kg), Ni (3.1-23.0 mg/kg), Pb (1.3-22.0 mg/kg), Co (2.9-5.6 mg/kg), Cr (2.7-11.1 mg/kg), Mn (2.0-7.1 mg/kg), and Cd (1.1 mg/kg 7.6). Although, Cd, Pb, and Zn concentrations in some of the WEM samples and Cd in the soil had exceeded the permissible limits set by different organizations. The greater accumulation/or transfer potential for Zn, Co, Ni, and Cu were recorded in WEM from their associated soil. The health risk index (HRI) for HM in all assessed samples of WEM was < 1, predicting no risk to the consuming population. Furthermore, the correlation analyses depicted that the power of hydrogen (pH), low organic matter contents, and sandy texture are likely to be responsible for HM transfer to the lower pool of soil. But the increasing concentration of HM in WEM warrants threats and suggests further monitoring and future policy plan and implementation to avoid the potential health risks via its regular consumption.

Keywords: Bio-accumulation; Health risks; Heavy metals; Soil; Transfer factor; Wild edible morels.