Heavy metal concentrations in riparian soils along the Han River, China: The importance of soil properties, topography and upland land use

Abstract

Riparian zones can act as an important sink for various contaminants, including heavy metals. The retention and accumulation of heavy metals in riparian soils varies spatially and is related to many local factors, such as soil properties, topography and land use. However, the relative importance of such factors in determining the heavy metal contamination of riparian soils remains unclear. In this study, we investigated the concentrations of 10 heavy metals (i.e., Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr and Zn) and their relationships to environmental features in 67 soil samples collected from 26 riparian sites along the Han River, China. Our results showed that there were significant and positive correlations among the concentrations of all heavy metals except for Ba, Mn and Sr. Heavy metal concentrations were, in general, positively associated with conductivity, fine substrate, carbon, nitrogen and phosphorus contents in soils but were negatively related to soil pH and density. Among the topographic conditions studied, elevation and distance from the river mouth were positively associated with the concentrations of Ba, Cd, Cr and Ni in riparian soils. Upland land use had a significant effect on the concentrations of Co, Cu and Zn. Generalized linear models revealed that soil properties, topography and land use together accounted for 11-69% of the variance in single metal concentrations, while redundancy analysis showed that such factors could explain 48% of the variance in overall metal levels. Our findings suggest that heavy metal concentrations in riparian soils are regulated not only by soil properties but also by physical characteristics such as topography and land use.

An integrated assessment of land-use change impact, seasonal variation of pollution indices and human health risk of selected toxic elements in sediments of River Atuwara, Nigeria

“…Riparian zones acting as aquatic-terrestrial links play a significant role in the environment by maintaining the balance between riverbank stability, water quality and aquatic biodiversity (Liu et al, 2016). Globally, riparian areas are considered as natural buffers that filter pollutants between upland regions and open waters, as well as reducing erosion at the stream bank (Ramião et al, 2020).…”

Accumulation and ecotoxicological risk assessment of heavy metals in surface sediments of the Olt River, Romania

“…Additionally, we observed that Pb was correlated negatively with elevation in both June ( r = − 0.41, p = 0.08) and October ( r = − 0.40, p = 0.08). Other research indicated a relationship between the decreasing trend of HM content and increases in elevation and river flow rate during the spring 68 . During the spring, the Pearson product-moment correlation coefficient demonstrated a strong ( p < 0.001) intermetal relationship in March for Pb vs. Cu ( r = 0.74), Pb vs. Zn ( r = 0.75), Ni vs. Cr ( r = 0.74), Ni vs. Cu ( r = 0.95), and Ni vs. Zn ( r = 0.80) and in May for Cd vs. Cu ( r = 0.73), Ni vs. Cr ( r = 0.90), and Ni vs. Cu ( r = 0.92) (Fig.…”

Sources, Spatial Distribution and Extent of Heavy Metals in Relation to Land Use, Lithology and Landform in Fuzhou City, China

“…Likewise, the correlations of As, Cu, Zn and Co with TN and TC suggest that heavy metals were influenced by organic matter content, as it may serve as a sink for metal(loid)s [13,39]. The result shows that improving the soil organic matter contents of the soil in the form of plant and animal residues, microbial biomass and other amendments may increase the metal(loid) adsorption of the soils and decrease soil contamination [16,39].…”