Heavy metals from different land use soil in the capital of ancient Pundranagar, Bangladesh: a preliminary study for ecological risk assessment

Safe levels of extractable heavy metals in land-uses urban soil have not been universally established. The pollution of land-uses soils in ancient Pundranagar, Bangladesh arouses growing interest because of severe anthropogenic stress, urbanization, ecotourism, overexploitation of natural resources, and discharges of industrial as well as municipal waste. Our study unfolds the extent of heavy metal pollution in the land-uses surface soil of this ancient terrestrial ecosystem and also investigates the contamination status, source, and ecological risks using pollution indices techniques. Total 90 soil samples were collected from six different land-uses and heavy metals were analyzed by inductively coupled plasma mass spectrometer. The concentration ranges of chromium (Cr), nickel (Ni), copper (Cu), arsenic (As), cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn) and zinc (Zn) in land-uses soils were 5.04-73.06, 18.26-313.2, 25.51-370.6, 4.83-36.30, 0.54-17.25, 8.60-187.9, 1128-8155, 35.04-129.1 and 8.60-187.9 mg/kg, respectively. Multivariate principal component analysis showed that Ni, Pb, Mn, Cu, and Zn in soil mainly from anthropogenic sources while As from lithogenic or natural sources. Considering the potential ecological risk, soil from all land uses showed moderate to high ecological risk. Analysis of the results indicates the alarming condition of this ancient terrestrial ecosystem.