Assessing the Presence of Petroleum Hydrocarbons in the Punta Carnero Estuary (Ecuador)

Abstract

Chronic hydrocarbon spills are a threat to coastal ecosystems, and their impact on the water quality along watercourses should be characterised to medium long term in order to assess the risk and define cost-effective and sustainable remediation strategies. For this purpose, a methodology for the measurement of total petroleum hydrocarbons (TPH) on a spatio-temporal scale was designed, implemented and validated in the Punta Carnero estuary, in the Santa Elena province, western Ecuador, which is affected by hydrocarbon pollution. The selection of monitoring stations was made according to the different inflows along the water system corresponding to the different anthropogenic activities in the area, in order to assess whether the effluents involve critical levels of pollution. Measurements of hydrodynamic, environmental and vegetation cover parameters were also carried out to assess their possible variations as a consequence of the impact of the spatio-temporal TPH concentrations. An increase in hydrocarbon concentrations was observed from 2013 to 2021. Mean annual TPH levels were above the maximum allowable limit for the protection of aquatic and other wildlife in estuarine waters according to the Ecuadorian regulation for environmental quality. An increase in mangrove tree cover could contribute to an exponential decrease in contamination levels. The methodology used in this study may support the quantifying of TPH content in future applications, which is a priority task for the restoration of degraded ecosystems.Graphical abstract