Burden of Disease from Coastal Water Pollution

Contamination of coastal water with pathogenic microorganisms is generally considered a relatively lesser environmental concern in developed nations such as the United Arab Emirates (UAE) that require treatment of municipal wastewater prior to discharge. In the Arabian Gulf in the 1990s, measurements of coliform bacteria (which indicate possible contamination with fecal matter and hence disease-causing organisms) generally supported this assumption, with reports of low average coliform concentrations along the coast. However, more recent data provided by the Environment Agency–Abu Dhabi indicate that concentrations of enterococci, which are the most important indicators of fecal contamination in coastal waters, at the city’s public beaches occasionally exceed World Health Organization recommended water quality standards. Additional observations of high coliform concentrations in nearby Abu Dhabi shipping channels and news reports of high E. coli concentrations along the Dubai coastline suggest that episodic events involving high concentrations of microorganisms of fecal origin may need to be addressed to preserve coastal water quality. Microorganisms in coastal water can enter the body through ingestion, inhalation, or transport through existing skin lesions or open wounds. Gastroenteritis (including diarrhea, vomiting, and associated symptoms) is the most common type of illness resulting from such exposures in developed countries. The analysis in this chapter focuses on risks due to pathogenic microorganisms of fecal origin because these organisms pose the most important public health risk from short-term exposure to coastal water as occurs during swimming and other coastal recreational activities. Further, at present, industrial effluents appear to be sufficiently regulated with no recorded violations, and a public notification system exists to warn beachgoers of “catastrophic” single incidents such as local oil spills or red tides. Our model estimates that swimming in UAE coastal waters could contribute to 1,300 medical visits for gastroenteritis per year among UAE residents. If the potential total number of illnesses (reported through medical visits and unreported) is considered, the estimate rises to 64,000. In addition to the cases among residents, another 24,000 cases could be expected among tourists. This suggests that virtually immediate reductions in health risks related to recreational waters could be achieved through increased monitoring of fecal indicator bacteria concentrations at local beaches and closure of areas in violation of international recommended standards until adequate reductions in microbial concentrations are achieved. Ideally, to provide consistent public health safeguards throughout the nation, a standardized coastal water monitoring program should be instituted at the federal level by the Ministry of Environment and Water and implemented by relevant emirate-level agencies.