Detection and analysis of organic pollutants in wastewater and their effect on proteins

Rhia Nelson, Tennessee State University


Part I: Water samples from environmental waters—namely the Mammoth Cave in Kentucky, the Harpeth and Cumberland rivers from Tennessee—were analyzed to determine the extent of organic pollutants. Tap water and deionized water samples were also collected and used as controls. Acid/base liquid/liquid extractions were performed on the water samples including the controls. The aqueous layers were discarded and the collected organic layers were stored temporarily at -20ºC before analysis. The dried organic layers were analyzed using a Varian Saturn Gas Chromatograph – Mass Spectrometer (GC-MS). Chromatograms of sample peaks were analyzed according to retention time using the GC-MS’s embedded library to determine the perspective compounds present. The detected compounds were classified as nontoxic, mildly toxic or toxic to humans based on the available information form the literature. The results indicate the presence of several organic pollutants, which may compromise the quality of drinking water for populations who largely depend on them. Part II: Polycyclic Aromatic Hydrocarbons (PAH) are a group of organic pollutants that form from the deficient combustion of hydrocarbons, such as gasoline and oil. PAHs are toxic to aquatic life and are assumed to be human carcinogens, which make them an environmental concern. Most PAHs do not dissolve in water but, instead, they bind strongly to sediments. PAHs are known to target proteins due their abundance in cells, stimulate the formation of reactive oxidative stress and produce free radicals. The importance of the role of oxidative stress in numerous of age-related diseases has become undisputable due to the huge amount of supporting evidence. One of the most projecting oxidative modifications of proteins is the introduction of carbonyl groups. In this study, anthracene and 7,12 Dimethylbenz (α)-anthracene (DMBA), at different doses of 0, 2, 4, 6, 8 and 10 μM, were tested at different incubation periods of 8, 12 and 24 hours to determine its bio-catalytic effect on hemoglobin and myoglobin using the Fenton’s pathway. Following the incubation, arginine residues in both proteins are measured using 9,10-phenathrenequinone (PTQ) and spectrophotometric determination of total protein carbonyl groups are quantified by using 2,4 dinitro phenylhydrazine (DNPH). The results indicate that arginine residues increased in a dose- and time-dependent manner following the exposure to anthracene and 7, 12 Dimethylbenz (α)-anthracene (DMBA) suggesting a possible mechanism of protein oxidation. The discovery of elevated levels of protein carbonyls is not only a sign of oxidative stress but also of a disease- related dysfunction. Thus, exposure to low doses of anthracene and DMBA may be harmful to proteins.

Subject Area

Environmental Health|Analytical chemistry|Biochemistry|Environmental science

Recommended Citation

Rhia Nelson, "Detection and analysis of organic pollutants in wastewater and their effect on proteins" (2015). ETD Collection for Tennessee State University. Paper AAI10003155.