Environmental pollution assessment of Al-Musk Lake, Jeddah, Saudi Arabia

Jeddah represents the second largest city in Saudi Arabia and has more than 3.5 million residents. The daily estimated water used per capita is 200 L. The absence of a well-done network of sewage in some places especially in south Jeddah (Old Jeddah) considered a serious environment. In Jeddah, the potable water used for municipal purposes is mostly returning to the surrounding environments as wastewater (e.g., Al-Musk Lake). The site Al-Musk Lake uses as sewage dumping lake without any purification processes till the year 2010. The wastewater of this lake caused various environmental dangers owing to heavy metal contamination of surface sediments, groundwater, soil and air. Its areal distribution has been increased during last 17 years (2000–2017). Its surface fine-grained sediments are including a huge amount of heavy metals and organic contaminants owing to accumulation of sewage water during the last two decades. The climate of the Saudi Arabia is mostly dry hot continental condition so that, the topmost clayey sediments of this lake are enriched in pollutants. That means, wind will carry these pollutants directly to Jeddah and the surrounding regions and are inhaled by residing citizens in these regions during respiration and thus could cause a variety of respiratory diseases or other infections. Owing to accumulation of sewage water-bearing organic materials during last 17 years, Al-Musk Lake subsurface sediments contain considerable amounts of heavy metals (Pb, Cd, As, Cu, Co and Hg) and organic materials. The organic matter content (OMC) of the studied surface soil samples varies from 4.2 to 11.3%. The OMC has a significant strong relationship with both silt and clay contents of the studied soil samples.