Leaching Behavior of As, Pb, Ni, Fe, and Mn from Subsurface Marine and Nonmarine Depositional Environment in Central Kanto Plain, Japan

Abstract

The leaching behavior of arsenic (As), lead (Pb), nickel (Ni), iron (Fe), and manganese (Mn) was investigated from subsurface core sediment of marine and nonmarine depositional environments in central Kanto Plain, Japan. A four-step sequential extraction technique was adopted to determine the chemical speciation, potential mobility, and bioavailability of metals under natural conditions in variable depositional environments. In addition, a correlation of these properties with pore water and total metal content was carried out. The concentration of As in pore water was found to be 2–3 times higher than the permissible limit (10 µg/L) for drinking water and leachate in fluvial, transitional, and marine environments. The trend of potential mobile fractions of As, Pb, and Ni showed Fe–Mn oxide bound > carbonate bound > ion exchangeable bound > water soluble in the fluvial environment. However, in the marine environment, it showed Fe–Mn oxide bound > water soluble > carbonate bound > ion exchangeable bound for As. The leaching of As in this fluvial environment is due to the organic matter-mediated, reductive dissolution of Fe–Mn oxide bound, where Mn is the scavenger. The amount of total content of As and sulfur (S) in transitional sediment reflects an elevated level of leachate in pore water, which is controlled by S reduction. However, the leaching of As in marine sediment is controlled by pH and organic matter content.

Spatial Distribution of Toxic Metal(loid)s and Microbial Community Analysis in Soil Vertical Profile at an Abandoned Nonferrous Metal Smelting Site

“…Higher pH values were obtained in the upper layer of soil possibly due to the effect of slags which contained alkaline minerals; and the lower pH values in the subsoil might ascribe to the acid red soil [ 22 ]. Besides, the ORP in different depth of soil was generally less than 300 mV, which mainly contributed to the anaerobic environment of soil [ 23 ]. The MC values in soil were about 20% and the values in top layer was slightly larger than the lower soil layer.…”

Assessment of contamination level of a Tanzanian river system with respect to trace metallic elements and their fate in the environment

“…A step-by-step Tessier and modified BCR sequential extraction methods were applied for the fractionation of the potential bioavailable forms of Fe in the sediments (Tessier 1979;Pueyo et al 2008;Sutherland 2010;Hossain et al 2019). Metal fractions were extracted by thoroughly mixing 1 g of oven-dried sediments in 12.5 mL of leaching solution.…”

“…The classification is based on the percentage of metals in the first three fractions (water-soluble, ion-exchangeable, and carbonate bound). These fractions together are regarded as very weakly bonded fractions and readily available for biological uptake (Hossain et al 2019).…”