Estudo do inseticida carbofurano em solo e sedimento de área de produção de arroz irrigado e controle do gorgulho aquático Oryzophagus oryzae, Taubaté, São Paulo, Brasil / Study of the insecticide carbofuran in the soil and sediment of paddy rice fields with control of the weevil Oryzophagus oryzae, in Taubaté, state of São Paulo, Brazil

Resíduos do inseticida e nematicida carbofurano e de seu principal metabólito 3-hidroxicarbofurano foram averiguados em tabuleiros de arroz irrigado e em áreas adjacentes para controle do gorgulho aquático da espécie Oryzophagus oryzae Lima, 1936. As amostras foram coletadas no período de 6/9/1999 a 4/5/2000 e analisadas por cromatografia a líquido de alta eficiência (HPLC) utilizando-se detector de fluorescência. Não foram detectados resíduos de carbofurano e de seu metabólito 3-hidroxicarbofurano dentro dos limites de determinação do método.

The presence of residues of the insecticide and nematicide carbofuran, used for weevil (Oryzophagus oryzae Lima 1936) control, and its principal metabolite 3-hydroxycarbofuran were evaluated in soil and sediment plots from paddy rice fields and adjacent areas. The samples were analyzed using a high-performance liquid chromatography and fluorescence detector. Carbofuran and 3-hydroxycarbofuran residues were not detected in any sample in amounts above the method’s detection threshold.

Population dynamics: seasonal variation of phytoplankton functional groups in brazilian reservoirs (Billings and Guarapiranga, São Paulo).

Phytoplankton may function as a 'sensor' of changes in aquatic environment and responds rapidly to such changes. In freshwaters, coexistence of species that have similar ecological requirements and show the same environmental requirements frequently occurs; such species groups are named functional groups. The use of phytoplankton functional groups to evaluate these changes has proven to be very useful and effective. Thus, the aim of this study was to evaluate the occurrence of functional groups of phytoplankton in two reservoirs (Billings and Guarapiranga) that supply water to millions of people in São Paulo city Metropolitan Area, southeastern Brazil. Surface water samples were collected monthly and physical, chemical and biological (quantitative and qualitative analyses of the phytoplankton) were performed. The highest biovolume (mm(3).L-1) of the descriptor species and functional groups were represented respectively by Anabaena circinalis Rabenh. (H1), Microcystis aeruginosa (Kützing) Kützing (L M/M) and Mougeotia sp. (T) in the Guarapiranga reservoir and Cylindrospermopsis raciborskii (Wolosz.) Seen. and Subba Raju (S N), Microcystis aeruginosa and M. panniformis Komárek et al. (L M/M), Planktothrix agardhii (Gom.) Anagn. and Komárek and P. cf. clathrata (Skuja) Anagn. and Komárek (S1) in the Billings reservoir. The environmental factors that most influenced the phytoplankton dynamics were water temperature, euphotic zone, turbidity, conductivity, pH, dissolved oxygen, nitrate and total phosphorous.

Giardia and Cryptosporidium in source waters of São Paulo State, Brazil.

Giardia lamblia and Cryptosporidium parvum are two protozoan intestinal parasites responsible for many drinking-water-related disease outbreaks in recent years. They are very resistant to conventional water treatment processes, can persist for long times in the environment and are, therefore, of great concern for public health. This work aimed to evaluate the presence of Giardia and Cryptosporidium in water sources from São Paulo State, Brazil, as part of the "Evaluation of Inland Waters from São Paulo State" project from CETESB. Over a period of 19 months, 278 water samples from 28 sites located in 10 watersheds were analysed. The immunofluorescence assay was used after concentration of the samples by the calcium carbonate flocculation technique. Thermotolerant (faecal) coliforms, faecal streptococci and Clostridium perfringens were also determined in order to verify the existence of correlation between these bacterial indicators and the protozoa. Giardia and Cryptosporidium were detected in 27% and 2.5% of the samples, respectively, a lower figure compared with the results reported by other authors, especially for Cryptosporidium. A Spearman rank correlation test demonstrated a significant correlation between Giardia and faecal indicator concentrations. According to the American Regulation of Monitoring (ICR), treated water from 16 of these 28 collection sites should also be analysed to evaluate whether the treatment process could remove the parasites. Some technical deficiencies of these methods still limit the utilisation of the monitoring results for public health decisions, but the data here reported will help to improve the quality of drinking water in São Paulo State.