Assessment of Current Risks of Excessive Heavy Metal Accumulation in Soils Based on the Concept of Critical Loads: A Review

Abstract

At the international level, the concept of critical loads developed under the Convention on Long-Range Transboundary Air Pollution directed by the United Nations Economic Commission for Europe is actively used to assess the risks of excessive inputs of pollutants into ecosystems. The review considers the main principles of the concept of critical loads and methods of its application for assessing the current risks of excessive accumulation of heavy metals (HMs) in soil as a component of terrestrial ecosystems from the standpoint of ecotoxicological effects (on plants, soil invertebrates, and microorganisms). Under this concept, the critical concentrations of Cd, Pb, Cu, and Zn for soils are for the first time estimated using the functions of critical concentrations taking into account the properties of soils (primarily, acidity and the contents of organic matter and clay). The main attention is paid to the rationale and development of the models for assessment of the critical concentrations and transfer functions connecting the concentrations of HM compounds in soils and soil solutions. The current environmental risks of excessive HM accumulation are assessed by comparing them with their critical concentrations. Current challenges and future prospects for analyzing the current environmental risks based on the concept of critical loads include the reduction in the uncertainty of estimates, combined effect of different metals in a multicomponent pollution, field validation of processes and modeling results, and the impacts of climate change and land use.

Bioavailability of Metals in the Biosphere

“…Climate makes a significant contribution to the formation of soil types, and these two factors, climate and soil type, largely dictate the mobility and availability of elements, including metals and metalloids (Nedrich & Burton, 2017;Koptsik & Koptsik, 2022). Arid climates, such as those in the western United States, tend to a low content of organic matter and high carbonate and salt abundances.…”

Comparative Analysis of Heavy Metal's Toxicity in Plants Physiology and its Remediation

“…Heavy metals availability in terrestrial ecosystems depends on soil characteristics, their physicochemical form, and plant species (Koptsik & Koptsik, 2022). A significant element of nutritional metal acquisition is the exudates released from roots into the rhizosphere through chelator assets.…”

Quantifying Heavy Metal Accumulation in Soil and Vegetation Surrounding Industrial Areas: A Comprehensive Environmental Toxicology Study

“…This body of research has consistently reported elevated concentrations of heavy metals in affected areas compared to control sites. For example, studies documented significant accumulations of lead, cadmium, and chromium in soil samples collected from areas adjacent to metal-processing industries (13,14). Similarly, increased levels of mercury and arsenic were found in vegetation near coal-fired power plants, showcasing the widespread impact of industrial emissions on environmental contamination (10,15).…”