Vulnerability of Human Populations to Contamination from Petroleum Exploitation in the Napo River Basin: An Approach for Spatially Explicit Risk Assessment

Abstract

Background: contamination of aquatic ecosystems by oil spills associated with petroleum exploitation represents a serious problem of environmental contamination that can affect human health. We developed a spatial model of contamination risk in the Ecuadorian Amazon, and evaluated the model using independent datasets on environmental contamination and clinical indicators of human health risk factors. Methods: the spatial risk of contamination for the Napo River basin was based on the calculation of a friction surface and the accessibility of possible oil contamination. Human health was evaluated using peripheral blood samples from 256 individuals. We used monitoring data on contamination to validate the spatial model of contamination risk and analyzed whether the estimated risk explained the incidence of human health risk factors. Results: our risk model showed a significant association with actual contamination detected in the study area. According to our risk model, around 30% of the territory has some level of contamination. Risk of contamination was associated with an increasing mean incidence in risk factors for human health in resident populations, but elevated contamination risk was not a significant predictor of the incidence of selected health indicators; only the incidence of inflammation was significantly increased. Conclusions: a large proportion of the populations in the Napo River basin has high vulnerability to contamination from petroleum exploitation, and this contamination risk may be traced in some indicators of health risk. Closer examination of health risk factors is warranted, and our spatial model of contamination risk can inform the design and analysis of such studies, as well as risk mitigation and management. Our approach to building the model of contamination risk could be applied in other catchments where petroleum exploitation is contemplated.

Bacterial Diversity in Old Hydrocarbon Polluted Sediments of Ecuadorian Amazon River Basins

“…Sample 23, in the Indillana River, also showed high concentrations of TPHs and PAHs, while sample 10, at the south shore of the Napo River, showed higher concentrations of TPHs, but not as many PAHs as would be expected. In addition, these three samples were rated with high levels of contamination risk predicted by the model of Espinosa et al [ 2 ]. This model is based on the accessibility of the contaminant, considering factors beyond the distance to the source of the spill, such as the area of contamination, the presence of runoff, and the flow of the watercourse, which influence the final impact of the contaminant.…”

“…Fourteen samples were analyzed in this phase and they were categorized into two groups based on TPH contamination levels: seven samples with low TPH concentrations (<90 mg kg −1 ) and seven samples with high TPH concentrations (>90 mg kg −1 ). In the final phase, the identification of microbial community structures in the different identified areas was addressed, covering the contamination risk spectrum evaluated by Espinosa et al [ 2 ] in the same region, according to three risk levels: 3 samples with low pollution risk (0–0.3), 2 samples with medium risk (0.3–0.6), and 3 samples with high risk (>0.6) ( Table 2 ). Through this comprehensive sampling design, we ensured the fulfillment of the study’s objectives by encompassing measurements of present hydrocarbon contamination (TPHs and PAHs), assessing microbial structures across the expected contamination risk spectrum, and determining the age of pollution.…”

“…One of the most significant non-renewable products for society is petroleum. However, petroleum exploration, extraction, processing, and transportation entail unavoidable pollution risks to the surrounding environment and human populations [ 1 , 2 , 3 ].…”

“…The hydrologic systems of these protected areas are linked to the Aguarico, the Coca and the Napo River basins, and the Limoncocha Lagoon, along with other important Amazonian rivers such as Capucuy, Itaya, Jivino, and Indillana [25], which are inhabited by the Kichwa, Cofán, Waorani, and Ai'cofan indigenous populations [23,26]. Therefore, in addition to the ecological impact of petroleum pollution, there are socio-economic and health repercussions [2,27,28], as more than 40,000 inhabitants of the Napo, Coca, and Aguarico basins use rivers, lagoons, and estuarine waters as sources of drinking water, cooking, personal hygiene, agriculture irrigation, and fishing [29].…”

Is the anemia in men an effect of the risk of crude oil contamination?

“…This region has a high risk of oil contamination that can affect human health. According to Espinosa et al [55] , 64% of population centers have different levels of risk contamination with a higher percentage (39%) of those centers exposed to a high risk of contamination. We selected locations using the categorized contamination risk map proposed by Espinosa et al (2021) to select sampling localities.…”