MODELING THE ENVIRONMENTAL IMPACTS OF POTENTIAL OIL PIPELINE LEAKS IN THE PÁRAMO REGION UPON THE WATER SUPPLY FOR QUITO, ECUADOR

The Trans-Ecuadorian Pipeline carries crude oil from oilfields in eastern Ecuador to refineries on the Pacific coast, crossing the Páramo region, an alpine tundra ecosystem within the province of Pichincha, which also serves as the water supply for the capital city of Quito. The objective of this study has been to create a model for predicting the likelihood that the effects of a crude oil spill in the Páramo region would impact the water supply of Quito by comparing the residence times of organic compounds in soil with the time required for microbial degradation. A custom MATLAB script included linear partitioning of multiple organic compounds among the water, air, soil and NAPL phases. The three organic compounds considered were anthracene, benzene, and naphthalene. The relevant soil parameters for the Páramo region were obtained from the ISRIC-WISE Harmonized Global Soil Profile Dataset. The soil organic matter content is a critical parameter that was estimated from a very small number of measurements. Residence time half-lives were calculated for depths of penetration of the initial spill ranging from 0.1-5 m. For a depth of penetration of 1 m, residence time half-lives for benzene, naphthalene and anthracene were 1.5, 23.1 and 247.8 years, respectively. Comparing with typical biodegradation half-lives of 10-730 days for benzene, 1‑258 days for naphthalene, and 199-252 days for anthracene, it can be seen that penetration to groundwater and transport to the reservoir that supplies water to Quito is unlikely for naphthalene and anthracene, but is a distinct possibility for benzene. Current modeling involves including the effect of volatilization within the soil and improving the estimates of biodegradation rates within an alpine tundra ecosystem. Further results will be reported at the meeting.