scholarly journals Source Apportionment and Ecological Risk Assessment of Potentially Toxic Elements in Cultivated Soils of Xiangzhou, China: A Combined Approach of Geographic Information System and Random Forest

2021 ◽  
Vol 13 (3) ◽  
pp. 1214
Author(s):  
He Huang ◽  
Yong Zhou ◽  
Yu-Jie Liu ◽  
Liang Xiao ◽  
Ke Li ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Information System ◽  
Geographic Information System ◽  
Random Forest ◽  
Ecological Risk ◽  
Ecological Risk Assessment ◽  
Toxic Elements ◽  
Geographic Information ◽  
Potentially Toxic Elements ◽  
Anthropogenic Sources

Soil is both an important sink and a source for contaminants in the agricultural ecosystem. To research the sources and ecological risk of potentially toxic elements in Xiangzhou, China, 326 soil samples from arable land were collected and analyzed for five potentially toxic elements: cadmium (Cd), mercury (Hg), arsenic (As), lead (Pb), and chromium (Cr). In this research, ecological risk assessment was used to determine the degree of contamination in the research area, the outcome of the Geographic Information System was as used to study the spatial distribution characteristics of potentially toxic elements, and random forest was used to evaluate the natural and artificial influencing factors. We surveyed the sources of potentially toxic elements through quantifying the indicators, which gave further opinions. The results were as follows: (1) The average contents of potentially toxic elements were 0.14 mg/kg (Cd), 0.05 mg/kg (Hg), 12.33 mg/kg (As), 28.39 mg/kg (Pb), and 75.21 mg/kg (Cr), respectively. The results compared with the background value of Hubei, neighboring regions, and countries for Cd, As, Pb, and Cr showed mild pollution. (2) The total evaluation of soil pollution via the comprehensive pollution index indicated slight contamination by Cd. Assessment by the potential ecological risk index indicated low ecological risk due to Cd and moderate contamination by Hg. Evaluation through the geo-accumulation index evinced the low ecological risk for Cd, As, and Pb and moderate contamination by Hg. (3) We found that in addition to natural factors (such as soil parent material, soil pH, etc.), long-term industrial pollution, mineral mining and processing, exhaust emissions from transportation, the application of manure from farms as farmyard manure, and sewage irrigation were the primary anthropogenic sources of potentially toxic element contamination in the soil.

scholarly journals Toxicity Impact on Bioaccumulation of Potentially Toxic Elements in African Giant Land Snail (Archachatina margenata) Treated with Different Soils and Its Ecological Risk Assessment

2019 ◽  
pp. 1-15
Author(s):  
Oguh C. Egwu ◽  
Ugwu C. Victor ◽  
Uzoefuna C. Casmir ◽  
Usman Sa’adat ◽  
Nkwocha C. Chibueze ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Ecological Risk ◽  
Ecological Risk Assessment ◽  
Toxic Elements ◽  
Land Snail ◽  
Potentially Toxic Elements ◽  
Soil Samples ◽  
Mining Site ◽  
Permissible Limits ◽  
Before And After

This study investigated the concentrations of heavy metals (As, Cd, Cr, Cu, Hg and Pb) in African Giant Land Snail (AGLS) treated with different soil samples dumpsite (A), mining site (B) and control soil (C) (a reserve area where no activities) use in farming AGLS and also to ascertain if they are within permissible limits and its ecological risk assessment on the consumption. Soil samples; at site A, B and C was collected at 0-30 cm depth with the aid of soil auger and were used for AGLS farming, to ascertain whether the potentially toxic elements (PTEs) concentration were within the permissible limits and their ecological risk assessment on AGLS consumption. A total of 54 juvenile snails of similar weights was used for the study. The experiment lasted for six month (182 days), during which the snails were subjected to similar dietary reign and equal quantity of feed. Snail’s morphological characteristics such as Weight, length and diameter of its shell were measured after farming. The soil samples were analysed for PTEs before and after farming, and snail were also analyzed for PTEs after farming for six month using atomic absorptions spectrophotometer (AAS). The ecological health risk from the consumption of these snails was assessed using standard methods and formulas. The result of different soil before and after farming shows a significant different (P<0.05) between the activities sites (dump and mining) and the control site. The concentration of PTEs (As, Cd, Cr, Cu, Hg, and Pb) in snails treated with dump site soil were 3.05, 3.89, 3.60, 2.89, 3.98, and 2.55 mg/kg, and snails treated with mining site soil recorded 2.73, 2.74, 3.91, 4.96, 2.88 and 4.82 mg/kg. The values were greater than the maximum permissible limit of 0.5, 2.0, 0.3, 0.04, 0.1 and 0.1 mg/kg respectively recommended by FAO/WHO compared to the control. The study concludes that snail bioaccumulate toxic elements from the soil used in rearing them which is deleterious to humans when consumed. Also the DIM, HQ, HI on the consumption of snail reared with dumpsite, mining site soils are nearly free of risks, but continuous consumption can lead to bioaccumulation in the food chain.

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