February 7, 2011 Hamilton
Pharmaceuticals, illicit drugs, personal hygiene products, chemical run-off … these and other pollutants are contaminating the giant aquifers under Mexico’s Riviera Maya district (a popular tourism district on the eastern portion of the Yucatán Peninsula), according to a recent UNU-INWEH study.
The area’s highly permeable geology is characterized by numerous cenotes (sinkholes) that provide access to groundwater cave systems, making the aquifers very susceptible to contamination. While the level of pollution is not yet considered to be a health threat, the problem will almost certainly worsen, particularly since the district’s population is predicted to increase by ten-fold in the next two decades.
The study’s findings “clearly underline the need for monitoring systems to pin-point where these aquifer pollutants are coming from,” said UNU-INWEH Senior Research Fellow Chris Metcalfe. “Prevention and mitigation measures are needed to ensure that expanding development does not damage the marine environment and human health and, in turn, the region’s tourism-based economy,” he added.
The study, part of UNU-INWEH’s Caribbean Coastal Pollution Project, was conducted with the cooperation of Amigos de Sian Ka’an, a local nongovernmental organization.
Among the groundwater pollutants found by the study were illicit drugs (cocaine and its post-digestion “metabolite” form, benzoylecgonine), chemicals from pharmaceuticals (including painkillers such as acetaminophen and ibuprofen) and personal care products (deodorants, perfume, toothpaste, hand-sanitizing lotion, etc.), caffeine, and a metabolite of nicotine.
The study points to pit latrines, septic tanks and leaking sewer lines as the likeliest sources of these pollutants, noting only one-third of the area is served by municipal wastewater treatment systems.
Pesticide applications (such as on golf courses) and run-off from highways and other paved surfaces are also sources of groundwater contamination.
The researchers note that the district has “a general lack of expertise and equipment for monitoring or tracking sources of pollution”, and that there are “few administrative links between those responsible for water and coastal management and the labs that generate the (monitoring) data”.
Among the countermeasures recommended by the study are the installation of impermeable liners beneath golf courses and other turf-covered areas to restrict the leaching of contaminants, nutrients and pathogens; lined and impermeable drainage canals, retention ponds and treatment systems; measures to minimize aquifer contamination from hard surface runoff; adequate wastewater treatment infrastructure; a halt to injections of treated sewage into saltwater below the freshwater aquifer; implementation of an integrated approach to coastal zone management; and protection of all remaining mangroves, which serve to buffer coastal areas from pollution.
Without integrated approaches to protecting and managing the aquifer, the UNU-INWEH study warns, “the tourism-based economy of the Maya Riviera region will not be sustainable over the medium to long term”.