Determination of Toxic Metals in Petroleum, Cultivated Land and Ore Samples Using Laser-Induced Breakdown Spectroscopy

Abstract

The growth of the petroleum industry worldwide and the marketing of petroleum products have resulted in the pollution of the environment with heavy metals due to oil spills and leakage from oil tanks and waste oil dumps. The effects of such pollution on the environment, humans, livestock, wildlife, aquatic life, crops, and soil have been enormous. The hazardous waste generated from the petroleum industry poses great dangers to human and animal health, especially since some of the waste is non degradable. For example, it could stay in the soil for many years and pollute precious water resources. The determination of nutrients and trace metal in soil samples is important due to the following reasons: i) soil contaminated with high concentrations of trace metals could pollute underground water resources, ii) within a single farming field, an agricultural producer may encounter non uniform distribution of nutrients (NUDN). Due to NUDN, the field may result in an over or under stress of nutrients (Lal, 1999). This can affect the overall crop yield. Precision farming, where uniform nutrient distribution is managed, is of growing interest among agriculturists and crop producers. In precision farming, management of nutrients allows growers to optimize inputs of nutrients like calcium, phosphorus, nitrogen, sulfur, iron and potassium, on a site-specific basis. By identifying sites where there is deficiency of nutrients in a field, farmers can create management zones and treat these areas with nutrients to enhance the crop yield. Hence the soil analysis is essential for guiding farmers to better identify fertilizer needs within a field. Many researchers are presently investigating optimum soil testing methods for precision agriculture. Efficient testing methods for measuring the concentration of nutrients are required for better estimates of crop yield. The interest in the analysis of ore samples is due to two main factors: i) runoff from mineral processing, and ii) open pit mines dumping tons of toxic waste into nearby water reservoirs, which can directly affect human life, vegetation and livestock in the region. Another significance of ore sample analysis is the determination of ore content quality and the identification of the constituents present in the ore sample. Thus the identification of analytical techniques for detecting elemental composition of ore samples is very important and needs rapid attention. Due to the above-mentioned reasons, a laser induced breakdown spectroscopy (LIBS) spectrometer was tested for the determination of heavy and toxic metals in crude oil residue sample obtained from a local oil producing company. The LIBS system was also tested for analysis of the soil samples collected from tomato cultivated green house soil. LIBS was also used for the chemical elemental analysis of ore samples. In addition to pollution control, information regarding the chemical composition of a substance is also of fundamental importance for numerous tasks during process control and quality assurance in industrial production units. M. A. Gondal (&) Z. H. Yamani Laser Research Laboratory, Physics Department, King Fahd University of Petroleum & Minerals (KFUPM), Box 5047, Dhahran 31261, Saudi Arabia e-mail: magondal@kfupm.edu.sa