Maria Therezinha Martins

Mutagenicity of airborne particulate organic material from urban and industrial areas of São Paulo, Brazil

The mutagenicity of airborne particulate matter at three different sites within the São Paulo urban area and the Cubatão industrial area, São Paulo State, Brazil, was evaluated using the Salmonella mutagenicity assay over a years period (June 1990-May 1991). Total suspended particles (TSP) were collected using a Hi-vol sampler and extracted with methylene chloride by ultrasonication. Pooled seasonal extracts were tested using S. typhimurium TA98 and TA100 with and without metabolic activation (S9) and TA98NR and TA98/1,8-DNP6 without metabolic activation. Organic extracts of the samples with the highest monthly TSP concentration were also assayed for mutagenicity. All samples collected at São Paulo and Cubatão showed mutagenicity with strain TA98, and in general the addition of S9 did not modify the mutagenic response, suggesting the prevalence of direct-acting frameshift mutagens in the atmosphere of these sites. The mutagenicity detected in the urban areas of São Paulo (mainly downtown) was much higher than in the Cubatão industrial area and similar to the more urbanized cities in the world, where vehicle emissions are the major pollution source. Results obtained with the strains TA98NR and TA98/1,8-DNP6 suggested the presence of mononitro- and dinitroarenes contributed to the mutagenicity of these atmospheric samples. A seasonal variation was observed with higher levels of frameshift mutagens during Spring in São Paulo and Summer in Cubatão. During the Winter, more significant responses were found with strain TA100 in the presence of S9 at all sites. Monthly samples presented high levels of mutagenicity during the period of June to November. Results from this research provide support for Air Pollution Control Programs in the detection of the more potent organic mutagenic compounds in the atmosphere and may help in the establishment of priorities for control and regulatory actions.

Assessment of microbiological quality for swimming pools in South America

Concerning the great importance of the safety of bathing water, and due to the dispute about the better microbiological indicator to assess the water quality of swimming pools, 1345 samples of water collected from 60 swimming pools in a period of four years were analyzed for total (TC) and fecal coliforms (FC), fecal streptococci (FS), heterotrophic bacteria (HPC), S. aureus (Sa), C. albicans (Ca) and P. aeruginosa (Pa). The frequency of positive results for these indicators ranged up to 70.4% (HPC), 13.3% (TC), 9.1% (Sa), 7.7% (FS), 5.6% (FC) and 2.0% (Pa and Ca). A correlation matrix (Spearman rank correlation) showed strong positive relationship among the levels of these microorganisms and between their densities and bather load and water temperature. As expected, all the microbiological variables presented a negative correlation with chlorine, C. albicans showing to be the more resistant to this disinfectant. Considering the good correlation among all these microbiological parameters, the highest rates of isolation of heterotrophic bacteria and total coliforms and the costs for microbiological analysis, it is possible to achieve an effective monitoring of swimming pool water quality by using only these two indicators, with no need of applying the other ones on a routine basis. P. aeruginosa and C. albicans, besides their high resistance to chlorine, presented a very low incidence and its use for evaluating swimming pool waters quality in routine is not indicated.

Evaluation of disinfected and untreated drinking water supplies in chile by the h2s paper strip test

Abstract Potable water studies have suggested that the presence of coliforms in contaminated potable water supplies was also associated with hydrogen sulphide producing organisms. Based on these observations, a paper strip testing method was used and modified to screen for bacteriological contamination of potable waters. The simplicity and low cost of the H 2 S paper strip technique, if applicable to tropical and subtropical potable waters, would provide countries with an affordable, locally produced water quality monitoring test. To evaluate the feasibility of this test, 622 drinking water samples, disinfected and non-disinfected, were collected from three districts in Chile and tested by the H 2 S paper strip method and total coliform MPN method and for coliphages. Results from this study indicated that (l) in treated and untreated drinking waters tested by the H 2 S paper strip and total coliform MPN test, the H 2 S test produced slightly more (10%) positive findings and (2) when the positive H 2 S paper strip samples were tested for coliforms, the number of H 2 S positive samples containing coliforms was similar to the number of samples testing positive by the total coliform MPN.

Qualidade bacteriológica de águas subterrâneas em cemitérios

Groundwater samples collected by piezometers from three cemeteries in geologically distinct areas of S. Paulo and Santos, Brazil, were analysed in order to determine their hygienic and sanitary conditions. Fecal coliformes, fecal streptococci, sulfite reducer clostridia and Salmonella were searched for the purpose of evaluating sanitary conditions, and total coliforms, heterotrophic bacteria, proteolitic and lipolitic microorganisms for evaluating hygienic conditions. In some samples, nitrate levels were also determined. It was discovered that these waters do not present adequate sanitary and hygienic conditions and that, in some cases, nitrate levels were extremely high (75.7 mg/l). In most samples, higher levels of fecal streptococci and sufite reducer clostridia than fecal coliforms were detected, which seems to show that the two former indicators would be more appropriate for evaluating the sanitary conditions of this kind of water. Salmonella were detected in only one of 44 samples analysed and coliphages in none. In the statistical analysis, the correlation matrix showed significant correlations among three fecal pollution indicators, as well as among anaerobic and aerobic heterotrophs and lipolitic bacteria. A direct relationship between the deterioration of water quality and the geological and hydrogeological conditions of the environment studied was observed. When cemeteries are constructed these conditions should, therefore, be taken into consideration.Foram analisadas amostras de aguas subterrâneas de tres cemiterios localizados em areas geologicamente distintas de Sao Paulo e de Santos, Brasil, com relacao as condicoes higienicas e sanitarias. Para as primeiras foram considerados os coliformes totais, bacterias heterotroficas, microrganismos proteoliticos e lipoliticos. Para as sanitarias foram pesquisados coliformes fecais, estreptococos fecais, clostridios sulfito redutores, colifagos e salmonelas. Verificou-se que as aguas nao apresentaram condicoes higienicas satisfatorias e, em alguns casos, foram encontrados niveis altos de nitrato (75,7 mg/l). A detecao de niveis mais elevados de estreptococos fecais e de clostridios sulfito redutores em relacao aos coliformes fecais, na maior parte das amostras, parece mostrar que os dois primeiros indicadores seriam mais adequados para avaliacao das condicoes sanitarias deste tipo de agua. Foi detectada Salmonella apenas em uma amostra e nao foram detectados colifagos. Na analise estatistica, foram encontradas correlacoes significantes entre tres indicadores de poluicao fecal assim como entre as contagens em placas de bacterias heterotroficas aerobias, anaerobias e lipoliticas. Foi observada uma relacao direta entre a deterioracao da qualidade da agua e as condicoes geologicas e hidrogeologicas do ambiente estudado, devendo este fator ser considerado para o planejamento e implantacao de cemiterios.

Evaluation of culture media for Candida albicans and Staphylococcus aureus recovery in swimming pools

Abstract S. aureus and C. albicans have been proposed as alternative indicators in swimming pools, so the upgrade of methods for detection of these microorganisms can provide better assessment of pool water quality. A total of 136 water samples collected from 25 public swimming pools in the city of Sao Paulo, Brazil were analyzed concerning the sensitivity and specificity of culture media in the recovery of S. aureus and C. albicans . For S. aureus , MF technique was applied, and five culture media were tested: Chapman-Stone, Chapman-mannitol, Baird-Parker, Vogel-Johnson and m- Staphylococcus agar. Typical colonies were characterized by catalase and coagulase activities and glucose and mannitol fermentation. Analysis of C. albicans was performed by quantitative (MF technique, m-CA agar) and qualitative (yeast nitrogen base glucose) procedures. Isolates from both procedures were characterized by germ tube and chlamydospore production and sugar assimilation. The superiority of m-CA agar with an accuracy level of 89.6% in C. albicans recovery was shown. In relation to S. aureus , Baird-Parker presented an increase in recovery from 5.7 to 17.2% than the other media. However, none of the media tested were sufficiently differential to permit the accurate identification of S. aureus in swimming pool waters.

Comparison of the presence-absence (P-A) test and conventional methods for detection of bacteriological water quality indicators

Abstract Fifty samples of water, comprising sewage-polluted river water and artificially-contaminated spring water, were analyzed in order to compare the P-A test and the conventional membrane filter and multiple tube methods for the detection of total and fecal coliforms, fecal streptococci, Pseudomonas aeruginosa, Staphylococcus aureus and sulfite reducer clostridia. The two presumptive media proposed for the P-A test, the MacConkey broth with tryptone (MacConkey-PA) and the lactose-lauryl tryptosetryptone broth (STM-PA), were also compared. The P-A test using STM-PA medium showed better results than the MacConkey-PA when water with lower levels of contamination (artificially-contaminated spring water) was analyzed. For coliform detection the P-A test with 48 h of incubation showed better results than with an incubation period of 5 days. For the detection of other indicators such as Ps. aeruginosa , sulfite reducer clostridia, and fecal streptococci in water with low levels of contamination the incubation period should be extended, as very different results after 48 and 120 h incubation were obtained with percentages of positivity being respectively, for Ps. aeruginosa , 48%, 76%; for sulfite reducer clostridia, 16%, 48%; and, for fecal streptococci 24%, 92%. Similar results were obtained for sewage polluted river water. Staphylococcus aureus was not detected by the P-A test. The P-A test using the STM-PA medium showed a good performance and is a promising tool for the evaluation of bacteriological quality of drinking water, especially in tropical climates where the coliform indicator may not be adequate. This test could overcome this problem, allowing the use of a multiple indicator approach.