A critical analysis of recreational water guidelines developed from temperate climate data and applied to the tropics.

Recreational water epidemiology studies are rare in settings with minimal wastewater treatment where risk may be highest, and in tropical settings where warmer temperature influences the ecology of fecal indicator bacteria commonly used to monitor recreational waters. One exception is a 1999 study conducted in São Paulo Brazil. We compared the risk and exposure characteristics of these data with those conducted in the United Kingdom (UK) in the early 1990s that are the basis of the World Health Organization's (WHO) guidelines on recreational water risks. We then developed adjusted risk difference models (excess gastrointestinal illness per swimming event) for children (<10 years of age) and non-children (≥10 years of age) across five Brazil beaches. We used these models along with beach water quality data from 2004 to 2015 to assess spatial and temporal trends in water quality and human risk. Risk models indicate that children in Brazil have as much as two times the risk of gastrointestinal illness than non-children. In Brazil, 11.8% of the weekly water samples from 2004 to 2015 exceeded 158 enterococci CFU/100 ml, the highest level of fecal streptococci concentration measured in the UK study. Risks associated with these elevated levels equated to median NEEAR-Gastrointestinal Illness (NGI) risks of 53 and 96 excess cases per 1000 swimmers in non-children and children, respectively. Two of the five beaches appear to drive the overall elevated NGI risks seen during this study. Distinct enteric pathogen profiles that exist in tropical settings as well as in settings with minimal wastewater treatment highlight the importance of regionally specific guideline development.

Are fecal indicator bacteria appropriate measures of recreational water risks in the tropics: A cohort study of beach goers in Brazil?

Regulating recreational water exposure to pathogens within the tropics is a major public health and economic concern. Although numerous epidemiological studies estimating the risk to recreational marine water exposure have been conducted since the 1950s, few studies have been done in the tropics. Furthermore, many have suggested that the use of fecal indicator bacteria for monitoring recreational water quality in temperate regions is not appropriate in the tropics. We analyzed a large cohort study of five beaches in Sao Paulo, Brazil, conducted during consecutive weekends in the summer of 1999 that estimated risk to water, sand, and food exposures. Enterococci and Escherichia coli concentrations were measured each day of the study. Elevated risks were estimated for both swimming (OR = 1.36 95% CI: 1.05-1.58) and sand contact (OR = 1.29 95% CI 1.05-1.58). A 1 log increase in enterococci concentration was associated with an 11% increase in risk (OR = 1.11 95% CI: 1.04-1.19). For E. coli a 1-log increase in concentration was associated with 19% increase in risk (OR = 1.19 95% CI: 1.14-1.28). Most countries with beaches in the tropics are lower or middle income countries (LMIC) and rely on tourism as a major source of income. We present data that suggests fecal indicator bacteria such as enterococci are an appropriate indicator of risk in tropical urban settings where contamination is coming from predominantly human sources. Additional studies in tropical settings could help inform and refine guidelines for safe use of recreational waters.

Sanitary quality of sands from marine recreational beaches of São Paulo, Brazil

A sanitary evaluation of sand and water from 16 beaches of São Paulo State, Brazil, was undertaken during spring of 1997 and summer of 1998. Ninety six samples each of wet and dry sand and seawater were collected and analysed for fecal indicator bacteria. A parasitological examination and Candida albicans analysis were also performed in sand samples and F-specific bacteriophages were determined in seawater. Statistical analysis of the results demonstrated higher concentrations of fecal coliforms and fecal streptococci in dry sand during summer. Correlation analysis indicated a significant relationship between fecal indicator densities in wet sand and seawater. There was a significant correlation between the densities of fecal coliforms and fecal streptococci for both types of sand, and this correlation was higher in wet sand. Cysts and eggs of parasites were detected in 4.2 percent of the samples and Candida albicans was isolated in 18 percent of the samples. The high concentrations of fecal indicators detected in sand during summer demonstrate that there is a health risk to the users of these recreational areas and suggest the necessity of some criteria for microbiological control. Preventive measures, such as education campaings and some management actions are important precautionary measures.

Dinâmica da serapilheira em manguezais de Bertioga, Regiäo Sudeste do Brasil / The litterfall dynamics in mangroves of Bertioga, SP, Southeastern region of Brazil

Os manguezais de Bertioga localizam-se próximos ao limite sul de distribuiçäo dessa comunidade vegetal na costa brasileira e no hemisfério sul. A produçäo de serapilheira desses bosques reflete seus baixos índices estruturais, embora sejam bosques de franja inundados duas vezes ao dia por marés de mais de 1 m de amplitude. A taxa média anual de produçäo de serapilheira foi de 5,6 t/ha no rio Iriri e 4,6 no rio Itapanhaú. Embora o processo de decomposiçäo seja intenso nesses manguezais pela existência de condiçöes favoráveis, a maior parte da renovaçäo se dá através da exportaçäo da serapilheira pelo movimento das marés. A partir da elaboraçäo de um modelo ecológico da dinâmica da serapilheira incluindo sua produçäo, estoque e decomposiçäo, foi possível estimar essa exportaçäo cujos valores estäo em torno de 0,7 gPS/m2 por dia com uma exportaçäo acumulada anual de cerca de 2,5 tPS/ha, o que significa que estes manguezais exportam aproxidamente 50 por cento da serapilheira que produzem. Essa dinâmica da serapilheira influencia também a ciclagem de nutrientes nesse ecossistema. A variaçäo anual da concentraçäo de nutrientes nas folhas da serapilheira mostrou um padräo sazonal com maiores valores no inverno e menores no veräo. Já as folhas verdes näo apresentam essa sazonalidade täo nítida: o que ocorre, portanto, é uma maior retranslocaçäo durante a época de maior produçäo de folhas, mantendo os teores desses nutrientes na copa