Exchangeable form of potentially toxic elements in floodplain soils along the river-marine systems of Southern Russia

Abstract

Large rivers and especially their deltaic parts and adjacent coastal zones are subjected to strong anthropogenic influence and are often considered as hotspots of environmental pollution. The Don River is one of the largest and most important rivers in the South of Russia. The Don River basin is a highly urbanized area with developed agriculture and industry which negatively affect water quality, aquatic ecosystems and soils. The main objectives of the proposed research were to determine the levels exchangeable form of PHEs in soils of various aquatic landscapes of the study area, as well as to reveal the relationships between the content of exchangeable PTEs and the physical-chemical properties of floodplain soils. The obtained results showed that soils of the Lower Don and Taganrog Bay coastal zone are rather contrast in terms of properties and metal contents, which indicates the variability of landscapes, natural and anthropogenic processes in the studied systems. High CV values for a number of metals such as Pb, Zn, Cd and Cr indirectly indicate strong anthropogenic influence on these environments. The group median values for extractable forms for most of the metals except for Cu and Ni were higher for urbanized areas. The results of PCA analysis showed that there are two association of metals in terms of geochemical behavior and sources. The first one included Cr-Zn-Pb-Cd, the elements of anthropogenic origin, the second Mn, Ni, and Cu, which are probably of mixed origin. The obtained results showed that the Lower Don and Taganrog Bay coastal zone is a diverse and complex system subjected to anthropogenic activities, which is pronounced in the enrichment of aquatic soils with a number of metals and higher proportions of exchangeable forms from different types of sources that likely can be of both local and whole basin scale. KKeywords: Floodplain, heavy metals, Fluvisols, the Don River, Taganrog Bay, Azov Sea.

Discharge Patterns of Potentially Harmful Elements (PHEs) from Coking Plants and Its Relationship with Soil PHE Contents in the Beijing–Tianjin–Hebei Region, China

“…This was in accordance with the literature, suggesting the Tianjin coastal area was one of the high-risk regions in China [ 52 ]. The coastal zone is usually a diverse and complex system subjected to diversified anthropogenic activities, which is pronounced in the enrichment of aquatic soils with a number of metals from different types of sources that likely can be of both local and whole basin scale [ 29 ].…”

“…At a regional scale, coal combustion may lead to differences in the temporal and spatial distribution of PHEs, leading to the heterogeneous distribution of risks caused by coking plants [ 28 , 29 ]. Current risk assessments mostly focus on the soil pollution status inside a certain coking plant, with few considerations of the pollution from coking plants to the surrounding soil through atmospheric deposition of coking gas [ 30 , 31 , 32 ].…”