A study on concentration of total petroleum hydrocarbons in lentic water bodies near oil field areas of upper Assam, India

Abstract

Aim Contamination of water and soil by crude oil and their accumulation in biota as a result of exploration, production, maintenance, transportation, storage and accidental release, add hazardous chemicals to the ecosystem. To determine the spatial and temporal variations of total petroleun hydrocarbon (TPH) concentrations in water, sediment and plant samples, a study was conducted in ten selected lentic water bodies in and around oil fields, group gathering stations and oil collecting stations of upper Assam, India. Methodology The samples (water, sediment and plant) were collected seasonally diring June, 2013 to May, 2014. Water samples were collected from the surface in amber colored glass bottles. The sediment samples were collected from 15 - 30cm depth below the water surface with soil sampler from three points (1/4,1/2 and 3/4) across the lentic water bodies in sterile polythene bags. Aquatic plant samples were uprooted, carefully separated from the soil and rinsed. The samples were transported to the laboratory in ice boxes under low temperature conditions and TPH extraction was done by standard methods. The extracted samples from water, sediment and plants were analysed fa TPH in Gas Chromatography. Results Results showed that both water and sediments contained significant (p < 0.05) concentration of TPH ranging behseen 89 to 843 mg 14 and 9643.35 b 59194.48 mg kgJ respectively. The collected plants also showed the presence of significant (p < 0.05) concentration of TPH in shoot (295 to 872 mg kg ') and in root (178 to 617mgkg4). Interpretation The TPH concentration in water, sediments and plants were relatively higher during the post monsoon season compared to winter and monsoon seasons. The TPH content in plants varied considerably with species.