ABSTRACT
Taking a city in Guangdong Province as the research area, the concentration and spatial distribution characteristics of heavy metals in the surface soil were studied to clarify the situation of soil heavy metal pollution and priority control factors, providing basic data for the prevention and control of soil heavy metal pollution in the city. The content characteristics of heavy metals in 221 soil samples in the city were analyzed, and the potential health risk assessment and source analysis were carried out through the Monte Carlo model, the potential health risk assessment (HRA) model, and the PMF receptor model. It was found that heavy metals ω(As), ω(Hg), ω(Cd), ω(Pb), ω(Cr), ω(Cu), ω(Ni), and ω(Zn) in the soil of the city were 18.16, 0.43, 1.46, 68.57, 98.34, 64.19, 26.53, and 257.32 mg·kg-1, respectively, with a moderate to high degree of variation. Except for Ni concentration, the soil concentrations of other heavy metal elements exceeded the background values of soil in Guangdong Province to a certain extent, and the concentrations of Cd and Zn exceeded the national secondary standards, resulting in severe heavy metal pollution; the main sources of heavy metals were industrial sources, and natural parent materials, lead battery manufacturing, transportation, artificial cultivation, and pesticide and fertilizer inputs also had an undeniable impact on the accumulation of heavy metals in the soil. Heavy metals in the soil had a certain degree of tolerable carcinogenic health risk for both children and adults, whereas non-carcinogenic risks could be ignored. The potential health risk of children was greater than that of adults, and the main exposure route was through oral intake. The input sources of pesticides and fertilizers and As should be the main controlling factors for the health risks of heavy metals in the city's soil, followed by mixed sources and Cr. There were differences in the spatial distribution characteristics and relative pollution levels of heavy metals, and it is necessary to deepen zoning monitoring and control, strengthen soil pollution prevention and control, and reduce human input of heavy metals in soil.
Subject(s)
Metals, Heavy , Soil Pollutants , Child , Adult , Humans , Environmental Monitoring , Soil , Cadmium/analysis , Soil Pollutants/analysis , Metals, Heavy/analysis , Risk Assessment , ChinaABSTRACT
In order to comprehensively study the pollution characteristics of polycyclic aromatic hydrocarbons ï¼PAHsï¼ in soils of Guangzhouï¼ 222 topsoil samples were collected and analyzed. The ecological risk of soil PAHs pollution was evaluated using the effect interval low/median method ï¼ERL/ERMï¼ and the ï¼BaPï¼ toxicity equivalent methodï¼ and the health risk of soil PAHs pollution was evaluated using the lifelong cancer risk increment model. The source of PAHs was analyzed using the characteristic compound ratio method and PMF model. The results indicated thatï¼ the content of surface soil ï¼∑16PAHsï¼ in Guangzhou was 38-11 115 µg·kg-1ï¼ with an average of 526 µg·kg-1ï¼ and 16 types of polycyclic aromatic hydrocarbon monomers showed strong variation. There was a certain degree of ecological risk of PAHs in Guangzhouï¼ and there was already a significant ecological risk of PAHs pollution in individual sampling pointsï¼ which were generally in a state of mild pollution. Based on the results of the health risk assessmentï¼ the contribution rates of total cancer risk in both adults and children were presented as followsï¼ skin contact > ingestion of soil > respiratory intake. The health risk of children was greater than that of adultsï¼ and the overall health risk was within an acceptable range. Source analysis showed that the main sources of soil PAHs in Guangzhou were coal ï¼37.1%ï¼ï¼ diesel ï¼32%ï¼ï¼ coking ï¼17.3%ï¼ï¼ and mixed sources of traffic emissionsï¼ biomass combustionï¼ and petrochemical product volatilization ï¼13.6%ï¼. The overall source of soil PAHs belonged to mixed sources. The research results have enriched our understanding of the pollution status of PAHs in the surface soil of Guangzhou and are helpful in promoting soil pollution prevention and control actions.
Subject(s)
Neoplasms , Polycyclic Aromatic Hydrocarbons , Soil Pollutants , Child , Adult , Humans , Soil/chemistry , Environmental Monitoring/methods , Polycyclic Aromatic Hydrocarbons/analysis , Soil Pollutants/analysis , Environmental Pollution/analysis , Risk Assessment , ChinaABSTRACT
Objective To evaluated the safety and feasibility of excimer laser atherectomy (ELA) combined with drug-eluting balloon angioplasty in treating chronic ischemia of lower limbs.Methods ELA combined with paclitaxel-eluting balloon angioplasty was adopted to treat chronic ischemia of lower limbs caused by arteriosclerosis occlusive disease of lower extremity in three patients.All three patients had arteriosclerosis occlusive disease of superficial femoral artery;in two of them the disease was primary occlusive lesion and in another patient the disease was in-stent re-occlusion lesion after sten implantation.Results After the treatment,the blood flow in the diseased arteries was unobstructed,the blood supply of the lower limbs was obviously improved.No procedure-related complications occurred.Two weeks after the treatment,no recurrence of ischemic symptoms was observed,the blood flow in superficial femoral artery kept unobstructed.The patients recovered smoothly.Conclusion For the treatment of chronic ischemia of lower limbs,which are caused by the primary arteriosclerosis occlusive disease of lower extremity or by the in-stent re-occlusion lesion after sten implantation,ELA combined with paclitaxel-eluting balloon angioplasty is clinically safe and feasible,although its long-term effect needs to be clarified with more studies.