Environmental Contamination by Industrial Effluents and Sludge Relative to Heavy Metals

摘要

Oman is located in the tropic of Cancer with extremely hot temperatures ranging between 15°C-25°C in winter and 30 - 48 in the summer with low rainfall. Most of the water source is desalinated seawater. Recycling of sewage effluent is a common practice used for farming, public parks and industry. The dried sludge product is used as fertilizer. The highly concentrated sludge with heavy metals is either incinerated or buried in landfills. Heavy metals were analyzed and compared in treated sewage effluent (TSE), slurry sludge, dried sludge, landfill and underground water. Heavy metal concentrations were analyzed using the inductive coupled plasma optical emission spectrometer (ICP-EOS). All samples contained the same heavy metals with different concentrations. The heaviest concentrations were Zn, Cu, Cr and Ni with traces of V, Cd, Pb and Ba. TSE and sludge were the main sources of landfill and underground water contamination. Due to water evaporation, heavy metals concentrations in sludge were higher compared to TSE and underground water. Dried sludge and landfill contained higher concentrations than the others. Based on this investigation, it appears that the source of heavy metals is from TSE originated mainly in industries. If the infiltration of heavy metals to soil and underground water continues, it will be a serious environmental and health problem in the future.