The occurrences of heavy metals in farmland soils and their propagation into paddy plants

Abstract

In this research, heavy metal accumulation pattern was investigated using the data measured from the soil, paddy plants, and irrigation water samples in Jessore district in Bangladesh with the aid of principal component analysis. A total of 28 samples representing farmland soil and irrigation water along with paddy plant were collected from 28 locations in the Jessore district in November 2016. In agricultural soil, arsenic (As) and nickel (Ni) were found 2.78 and 1.11 times more concentrated than their background values. In addition, 89% of the sample sites exhibited enhanced As concentrations relative to the background value. Principal component analysis (PCA) of soil data showed strong homogeneity in many species (e.g., Ni, Cu, Fe, and As) to reflect intense agricultural activities. In contrast, Pb showed no such homogeneity in soil accumulation pattern. In plant samples, Cu, Fe, and As were strongly correlated and homologous. This homology of pollution was in agreement with the pollution homology in the agricultural soil in which the plants were grown. In irrigation water, Cu and Ni were homologous. Observation of spatial distribution and other variables indicated that the accumulation of any particular metal in paddy plants was correlated with its content in soil and irrigation water, which was influenced by the soil organic matter, soil/water pH, and other metals present in that environment.

Keywords: Arsenic; Heavy metals; PCA (principal component analysis); Spatial distribution; Statistical modeling.