Health risks caused by freshwater cyanobacteria in recreational waters.

Toxic cyanobacteria are increasingly being perceived as a potential health hazard, particularly in waters used for recreation. A few countries are developing regulations to protect human health from these toxins, and the World Health Organization (WHO) has published both a guideline value for one cyanotoxin in drinking water and a procedural guideline for recreational waters. This article presents an overview of the currently known cyanotoxins and of documented cases of human illnesses attributed to them. It further discusses exposure pathways and approaches to risk management. In this context, the WHO guideline for recreational waters is presented, and monitoring approaches are outlined.

[Quality of water in the marine environment. The history and application of microbiology standards]. / Calidad del agua en el medio marino. Historia y aplicación de normas microbiológicas.

The history and application of microbiological standards to measure the quality of seawater for primary-contact recreational use and for the harvesting of shellfish are reviewed. Recent research concludes that enterococci, as indicator organisms, provide the most accurate correlation with gastrointestinal disorders attributed to swimming in contaminated waters. Accordingly, a linear relation has been established between mean enterococcus density per 100 ml and swimming associated gastrointestinal disorders per 1,000 population, and in 1984 the U.S. Environmental Protection Agency (EPA) adopted these bacteria as the primary indicator organisms for recreational waters in lieu of the indicators applied up til then, mainly total and fecal coliforms. International, national, and local microbiological standards and guidelines are presented to provide the sanitary engineer with a water quality range for the marine environment. Before adaptation of particular set of standards, local and national circumstances as well as socioeconomic factors should be carefully reviewed. Moreover, the application of quantitative relationships between health risks and the level of indicator organisms should take into account the general health and immunity conditions of the local population.

Developing alternative approaches to urban wastewater disposal in Latin America and the Caribbean

The explosive rate of urbanization and industrialization in Latin America and the Caribbean has aggravated serious wastewater disposal problems. To address those problems, sound pollution control programs are needed - programs that are founded on a firm legal base and supported by an institutional infrastructure suitable for their effective operation. Such programs should make a point of employing technologies that are appropriate for the climatic and economic conditions prevailing in the areas they serve. Promising methods for dealing with such problems include use of submarine outfalls with minimal pretreatment for cities along coasts and estuaries, maximum use of receiving waters' assimilative capacity (as determined through application of system management and water quality models), reuse of treated sewage effluent for irrigation, and the application of unconventional technology for urban slum sanitation. This article reviews those various approches and describes the ongoing collaboration between national governments and PAHO's Pan American Center for Sanitary Engineering and Environmental Sciences (CEPIS) in the areas of research, information exchange, human resources development, and institutional development for the purpose of establishing a viable strategy and framework through which these major problems can be confronted and perhaps ultimately over come.(AU)