Monitoring hydrocarbons and inorganic compounds in a Lebanese river : case of Nahr Ibrahim

Abstract

About 80% of the Earths surface is covered by water, but only 1% of that is fresh water that can directly be used for domestic, industrial, commercial, and recreational purposes. Although there is the same amount of water as millions of years ago, the demand for water has increased dramatically. Increased demand and diverse use for water has put enormous stress on our water supply, its quality and the aquatic life and habitat it sustains. Through the process of the water cycle, the same water is continually recycled. Pollution from human activities upsets this delicate natural purification process. Land and water use are interconnected and water quality is affected by how the surrounding land is used. Almost everything we do on the land impacts the water. However, water resources in Lebanon are limited and decreasing. Past studies indicate that 70 percent of the water resources in Lebanon were polluted in the early 1990s. Significant number of hydrocarbon compounds are ubiquitous environmental pollutants that posses carcinogenic and mutagenic effects on living organisms including humans. Organic compounds can be a major pollution problem in groundwater, surface water and soil in Lebanon. Their presence in environment can create a hazard to public health and the environment. Such hazardous organic compounds are the BTEX. The term of BTEX refers to Benzene, Toluene, Ethylbenzene and three isomers of Xylene. They are some of the volatile organic hydrocarbons (VOHs) that make up a significant percentage of petroleum products and are found in petroleum derivates such as gasoline. BTEX are used as gasoline. They are also used extensively in manufacturing processes such as in the production of synthetic materials and consumer products, like synthetic rubber, plastics, nylon, insecticides, solvent for paints, coatings, gums, oils, resins, inks, plastics, printing pesticides and leather industries. Usually they are often found together at contaminated sites. All these substances are important to be investigated due their adverse health effects on humans such as destruction of the central nervous system. Longer exposure to these compounds release in the destruction of the kidney, liver and blood systems. Also according to the U.S. Environmental Protection Agency (U.S. EPA), there is sufficient evidence from both human and animal studies to believe that some of these compounds are human carcinogen. The purpose of this study is to test the levels of BTEX compounds in Nahr Ibrahim River and monitoring the physical and inorganic parameters. BTEX compounds were analyzed by using Gas Chromatography coupled to Mass Spectrometry (GC-MS) technique. Inorganic compounds were analyzed by using DR5000 spectrophotometer. Six sampling sites along the length of the river were chosen. Sampling was conducted monthly during the dry season of 2012. The examination of BTEX compounds in the surface water of Nahr Ibrahim River shows that the river is contaminated with Benzene. The concentration of Benzene was above its maximum contaminant level set by U.S. EPA which is 0.005ppm.The presence of benzene in the river can be explained by the presence of surrounding companies and agricultural lands. Concentrations of toluene and Xylene were very low compared to their MCL. Whereas, Ethylbenzene compound was absent in all the six locations of the river. All inorganic and physical parameters concentrations were below the U.S.EPA MCL except the phosphate level which was higher than 0.1mg.L-1. All results were correlated with GIS system and discussed.