Preliminary environmental assessment of the pollution of soil and water at Wadi Uranah, Makkah Al-Mukarramah, Saudi Arabia

Abstract EN

The environmental impact of sewagewater effluent discharged into the lower part of Wadi Uranah, Makkah Al-Mukarramah area on soil and underground water was evaluated.

Water samples from the stream and the adjacent wells, in addition to soil samples from the wadi and the stream were collected.

Chemical analysis and bacterial examinations for stream wastewater, contaminated well water, stream polluted soil and wadi unpolluted soil were performed.

Physical properties for soil samples were also determined.

The results of chemical analyses revealed that, the values of most of the tested elements are higher in wastewater than in well water except for pH, Ca, Mg, Fe, Cl, Ni, Cr, and Cu.

It was also found that, the BOD, COD, NO3 and the heavy metals such as Zn, Mn, Cu, Ni, Pb, Cr and Cd, in the tested wastewater, are higher than the permissible standard limits, in addition to the presence of huge quantities of infectious bacteria.

The amount of Zn, Pb and NO3 in the wastewater and polluted soil are extremely high.

Sewagewater was found more contaminated than the well-water.

Furthermore, the values of Ca, Mg and PO4 are higher in the wadi soil than the polluted soil.

The study indicates that, the sewagewater and the well water, in their present condition, are not suitable and unhealthy for human consumption or domestic and irrigation purposes.

This situation was due to the presence of high concentration of organic materials, salts, heavy metals and bacteria.

The study results also indicated that the treated wastewater in the stream is unfit for direct discharge and reuse.

The farms should be prevented from the use of wastewater either directly or from the contaminated wells.