Evaluation of potential contamination of groundwater and spring protection areas of the Maravilla-Chiz and Quebrada Honda sub-basins, Cartago, Costa Rica

The threat of groundwater contamination was determined by evaluating the state of the protection areas in public supply springs. Potential point, line, and diffuse sources of contamination were considered and classified according to the POSH (Pollutant Origin and its Surcharge Hydraulically) method. Results identified that 7% of the area showed diffuse sources of high potential generating pollutant load, due to the large quantities of pesticides used in greens and vegetables, while 55% presented a moderate potential in plots of sugarcane, coffee, and urban areas with no sanitary sewer. Half of the point sources found were classified as a high potential and 46% as moderate. Of the 252 line-kilometers corresponding to rivers, road network, and pipeline, 89% was classified as moderate potential, 10% as high, and 1% as reduced. Finally, the invasion of line and diffuse sources in the spring protection areas was confirmed; therefore, the local government is recommended to start a legal procedure to address the problem