Assessment of seawater quality and bacteriological pollution of rocky shores in the central coast of San Jorge Gulf (Patagonia, Argentina).

We assessed seasonal and spatial variability of seawater quality and bacterial pollution in two sewage-impacted and two reference rocky shores in the area of Comodoro Rivadavia, the largest city in central Patagonia. Samples taken from winter 2015 to autumn 2017 at different intertidal levels showed that the impacted sites experienced a decrease of salinity-more pronounced towards the autumn-, a slightly higher turbidity, the lowest values of dissolved oxygen, and significantly higher concentrations of nitrates throughout the year. They also were up to ten times above the legal limit of fecal indicator bacteria (FIB) for recreation and fishing areas. Enterococci increased particularly during winter. All bacteriological indicators decreased markedly during spring. Principal component analysis arranged the reference sites mostly by their higher salinity, and the impacted sites by concentration of FIB, nitrates and phosphates. Impacted and reference sites overlapped towards lower levels, where the explicative variables were more stable.

Coliform and metal contamination in Lago de Colina, a recreational water body in Chihuahua State, Mexico.

Lago de Colina (Colina Lake) is located about 180 km south of the city of Chihuahua (Mexico), and during the Semana Santa (Holy Week) vacation period its recreational use is high. The objective of this study was to quantify coliform and heavy metal levels in this water body before and after the Holy Week vacation period in 2010. Twenty sampling points were randomly selected and two water samples were collected at each point near the surface (0.30 m) and at 1 m depth. After the Holy Week vacation the same twenty points were sampled at the same depths. Therefore, a total 80 water samples were analyzed for fecal and total coliforms and levels of the following metals: Al, As, B, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se, Si and Zn. It was hypothesized that domestic tourism contaminated this water body, and as a consequence, could have a negative impact on visitor health. An analysis of variance (ANOVA) study was performed for each element and its interactions considering a factorial design where factor A was sample date and factor B was sample depth. Fecal coliforms were only detected at eight sampling points in the first week, but after Holy Week, both fecal and total coliforms were detected at most sampling points. The concentrations of Al, B, Na, Ni and Se were only statistically different for factor A. The levels of Cr, Cu, K and Mg was different for both date and depth, but the dual factor interaction was not significant. The amount of Ca and Zn was statistically different due to date, depth and their interaction. No significant differences were found for any factor or the interaction for the elements As, Fe and Mn. Because of the consistent results, it is concluded that local tourism is contaminating the recreational area of Colina Lake, Chihuahua, Mexico.

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% of the samples and Candida albicans was isolated in 18% 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.

Foi realizada uma avaliação sanitária das águas e areias de 16 praias do litoral do Estado de São Paulo, Brasil, durante a primavera de 1997 e verão de 1998. Cento e noventa e duas amostras de areia seca e úmida, e 96 amostras de água do mar, foram coletadas e analisadas quanto à presença de bactérias indicadoras de contaminação fecal. Também foram realizados exames parasitológicos e análises de Candida albicans nas amostras de areia, e a determinação de bacteriófagos F-específicos nas amostras de água. A análise estatística dos resultados demonstrou concentrações mais elevadas de coliformes e estreptococos fecais na areia seca, durante o verão. Observou-se uma correlação significativa (Pearson) entre as concentrações de coliformes fecais e estreptococos fecais para os dois tipos de areia, correlação esta mais elevada na areia úmida. Ovos e cistos de parasitas e C. albicans foram detectados em 4,2% e 18% das amostras, respectivamente. As elevadas densidades dos indicadores de contaminação fecal detectadas nas areias durante o verão mostram a necessidade de orientar-se adequadamente a população a respeito das doenças veiculadas pela areia e das medidas preventivas necessárias, bem como de buscar-se um critério adequado para monitorar esse risco.