Pollution Levels and Risk Assessment of Heavy Metals in the Soil of a Landfill Site: A Case Study in Lhasa, Tibet

Abstract

As an important ecological security barrier in China, the ecological environment of Tibet has aroused widespread concern domestically and overseas. Landfills are a major solid waste treatment approach in Tibet but also cause severe environmental pollution. To date, there are no studies related to the pollution risk of landfills in Tibetan areas. This study investigated the pollution levels, ecological risk, health risk, and possible pollution sources of eight heavy metals in the soils around a landfill site in Lhasa, Tibet. The results indicated that the concentrations of heavy metals in soil were relatively low, only cadmium (Cd), arsenic (As), copper (Cu), chromium (Cr), zinc (Zn), nickel (Ni), and lead (Pb) were 1–2 times higher than the corresponding background value. The values of the single pollution index and geo-accumulation index show that the study area is most seriously polluted by Cd and As. Based on the Nemerow pollution index and the pollution load index, over 83.3% and 8.33% of soil sampling sites had light and moderate contamination levels. According to the results of potential ecological risk evaluation, the potential ecological risk of heavy metals in soil was very low, and only one out of the 72 sampling sites exhibited considerable ecological risk. Cd, As, and mercury (Hg) served as the dominant ecological risk contributors and contributed over 45.0%, 14.1%, and 18% of the ecological risk. The results of the health risk evaluation showed that adults have a higher risk of cancer (1.73 × 10−5), while the non-carcinogenic risk for adults was low. Waste disposal activities and construction activities have a significant influence on soil heavy metal concentrations, causing a higher pollution level in the southeast part of the landfill site in Lhasa.

A comprehensive investigation of geoenvironmental pollution and health effects from municipal solid waste landfills

“…Olagunju et al ( 2020 ), based on their research performed in the area of Awotan Landfill in Ibadan (Southwest Nigeria), also found that inhalation of soil does not pose health hazards due to HMs. Similar to our study, Obiri-Nyarko et al ( 2021 ) and Zhou et al ( 2022 ) found that direct ingestion is a major pathway for exposing humans to HMs at landfill sites.…”

“…human activities). Raising awareness of the presence of even minor increments of Cd in soils remains a matter of utmost importance when formulating necessary remediation strategies (Zhou et al, 2022 ). It is particularly important as Cd is recognized as one of the most environmentally toxic HMs, known to exert highly detrimental effects on soil health, biological activity, plant metabolism, as well as the overall well-being of humans and animals (Ihedioha et al, 2017 ).…”

“…Major factors influencing contaminants release and increase in HMs concentrations in soil are related to waste disposal, leachate and geothermal wastewater discharge, the energy sector, and the automotive industry (Kosowski et al, 2019 ; Trach, 2020 ; Tucki et al, 2020 ; Wang et al, 2020 ). Zhou et al ( 2022 ) highlighted that the primary source of HMs could be associated with the siting and operation of waste disposal facilities such as waste treatment centres, domestic waste incineration plants, and leachate treatment stations.…”

Exposure Factors in Health Risk Assessment of Heavy Metal(loid)s in Soil and Sediment

“…There are many variations in the definition and presentation of the average daily intake of HMs, and some researchers completely omit the separate definition of the daily intake equation. In that case, this equation must be integrated with the equations for HI and TCR indices [14,110]. Another term encountered is ADD total , which represents the sum of all three ADD for different routes of exposure [102,107].…”

A comprehensive model for quantifying construction waste in high-rise buildings in India

“…Unlike reuse and recycling, landfilling of CDW poses a serious threat to the ecosystem causing environmental pollution, thereby jeopardizing human health and social well-being (Omer and Noguchi, 2020; Zhou et al, 2022) due to its massive proportion and huge weight (Galvez Martos et al, 2018). Considering the current rate of natural resource extraction, there will be a severe shortage of raw materials in the near future.…”