Soil Pollution Research Papers - Academia.edu (original) (raw)

Background and Objective: Changes in the pattern of land use through the process of industrialization, infrastructure development and agricultural development is causing environmental issues such as soil pollution. The soil contamination with heavy metals is a serious and expanding problem. Heavy metals entering the food chain, threaten ecosystem and human health. This study aimed to assess and monitor soil contaminants including heavy metals and total petroleum hydrocarbons (TPHs) in soils of five oil refineries.
Materials and Method: In the current study oil- contaminated soils from five refineries including Abadan, Isfahan, Tabriz, Tehran and Shiraz were collected and physical, chemical and biological characteristics of soils examined. Total petroleum hydrocarbons (TPHs) and heavy metals (cadmium, chromium, lead and nickel) in soil samples were measured and the data was ststistically analysed.
Result: TPH levels in contaminated soils of Abadan, Isfahan, Tabriz, Tehran and Shiraz were 6.4 , 13.8 , 11.5 , 2.1 and 15.4 percent respectively and positively correlated with organic carbon of soil amples. The values obtained here were higher than the national and international standards. The highest concentration of chromium (mg/kg) was recorded in Abadan (83.3), Tehran (212) and Shiraz (61.1) refineries. The highest concentrations of nickel (mg/kg) were obtained from Tabriz (76.3) and Isfahan (122.1) respectively. The amount of cadmium and nickel in soil was higher than the standards of Europe and the world. A significant negative correlation was observed between heavy metal and hydrocarbon concentrations and microbial respiration, suggesting negative effects of pollutants on soil microorganisms which may also affect plants and other organisms.
Conclusion: In terms of heavy metals and petroleum hydrocarbon contamination, Tehran Refinery is in a better situation compared to other refineries, and this might be due to an environmental action plan running in this refinery. Given the contamination of refineries` soil, it is recommended that environmental monitoring and industrial cleaning is taken into consideration . It is also recommended to use filtering programs, including bioremediation of soil in these areas.
Result: TPH levels in contaminated soils of Abadan, Isfahan, Tabriz, Tehran and Shiraz were 6.4 , 13.8 , 11.5 , 2.1 and 15.4 percent respectively and positively correlated with organic carbon of soil amples. The values obtained here were higher than the national and international standards. The highest concentration of chromium (mg/kg) was recorded in Abadan (83.3), Tehran (212) and Shiraz (61.1) refineries. The highest concentrations of nickel (mg/kg) were obtained from Tabriz (76.3) and Isfahan (122.1) respectively. The amount of cadmium and nickel in soil was higher than the standards of Europe and the world. A significant negative correlation was observed between heavy metal and hydrocarbon concentrations and microbial respiration, suggesting negative effects of pollutants on soil microorganisms which may also affect plants and other organisms.