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Pollution levels have been increasing in water ecosystems worldwide. A water quality index (WQI) is an available tool to approximate the quality of water and facilitate the work of decision-makers by grouping and analyzing numerous parameters with a single numerical classification system. The objective of this study was to develop a WQI for a dam used for irrigation of about 5000 ha of agricultural land. The dam, La Vega, is located in Teuchitlan, Jalisco, Mexico. Seven sites were selected for water sampling and samples were collected in March, June, July, September, and December 2014 in an initial effort to develop a WQI for the dam. The WQI methodology, which was recommended by the Mexican National Water Commission (CNA), was used. The parameters employed to calculate the WQI were pH, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS), total hardness (TH), alkalinity (Alk), total phosphorous (TP), Cl-, NO3, SO4, Ca, Mg, K, B, As, Cu, and Zn. No significant differences in WQI values were found among the seven sampling sites along the dam. However, seasonal differences in WQI were noted. In March and June, water quality was categorized as poor. By July and September, water quality was classified as medium to good. Quality then decreased, and by December water quality was classified as medium to poor. In conclusion, water treatment must be applied before waters from La Vega dam reservoir can be used for irrigation or other purposes. It is recommended that the water quality at La Vega dam is continually monitored for several years in order to confirm the findings of this short-term study.

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Irrigation water has been recognized as an important microbial risk factor for fruits and vegetables in many production areas, but there is still a lack of information about how the microbiological quality of different irrigation water sources and climatic conditions influence the safety of vegetables produced in Brazil. This study evaluated the distribution of generic E. coli and the prevalence of E. coli O157:H7 in two different water sources (ponds and streams bordering farmlands and urban areas) used for irrigation and on commercially produced lettuces in Southern Brazil. We also evaluated the effect of agricultural factors and meteorological conditions in the potential contamination of water and produce samples. A longitudinal study was conducted on four farms during a year (July 2014 to August 2015). The results showed generic E. coli prevalence of 84.8% and 38.3% in irrigation water samples and on lettuces, respectively, indicating irrigation water as an important source of contamination of lettuces. No significant differences were detected in the counts of E. coli between the two different surface water sources. The climatic conditions, particularly rainfall and environmental temperature, have influenced the high concentration of E. coli. The highest loads of E. coli in irrigation water and on lettuces were found during the warmest time of the year. E. coli O157:H7 was detected by qualitative polymerase chain reaction (qPCR) in 13 water samples but only 4 were confirmed by isolation in culture media.

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A presença de Salmonella spp.,que é um patógeno de importância clínica, tem sido detectada em lodos de esgoto gerados ao redor do mundo. O objetivo desse estudo foi o de estimar o risco anual de infecção relacionado à ingestão de alface, tomate e cenoura cultivados em solos acondicionados com o lodos de esgoto provenientes de cinco Estações de Tratamento de Esgoto (ETEs) da Região Metropolitana de São Paulo bem como o risco de infecção anual que trabalhadores agrícolas, através da ingestão involuntária de partículas de solo, são submetidos. Como no Brasil ainda não há o estabelecimento de valor de risco tolerável, o valor usado pela USEPA, de 1/10.000 (10-4), foi utilizado para que a comparação com os resultados obtidos fosse realizada. Métodos Foram coletadas 54 amostras de lodos de esgotos de cinco ETEs num período de 12 meses (janeiro a dezembro de 2011). A concentração de Salmonella spp nessas amostras foi obtida utilizando o método USEPA 1682/2006. Foram selecionadas 40 cepas isoladas e identificadas como Salmonella spp. para sorotipificação em laboratório de referência. Essas cepas foram submetidas à detecção dos genes de virulência invA, ssel e spvC, presença de plasmídeo por técnicas moleculares e ainda à resistência a antimicrobianos. Para a estimativa dos riscos anuais de infecção por Salmonella foram desenhados nove cenários diferentes considerando como fatores principais a presença ou ausência da variação da concentração de Salmonella spp. nos solos...

Introduction - The presence of Salmonella spp., an important pathogen, has been reported in sewage sludge worldwide. The aim of this study was to estimate the annual risk of infection related to ingestion of lettuce, tomatoes and carrots grown in soil conditioned with sewage sludge from five Wastewater Treatment Plant (WWTP) in the Metropolitan Region of São Paulo. Also the annual risk of infection of farm workers through involuntary ingestion of soil particles were estimated. As in Brazil there is no establishment of the value of tolerable risk, the value used by the USEPA, 1/10,000 (10-4), was adopted in order to proceed the comparison with the results obtained. Methods - 54 samples of sewage sludge from the five WWTPs were collected over a period of 12 months (January to December, 2011). The concentration of Salmonella spp. in these samples was obtained using the method 1682/2006 USEPA. 40 strains identified as Salmonella spp were selected for serotyping in a reference laboratory. These strains were subjected by molecular techniques to detection of virulence genes invA, sseL and spvC, presence of plasmid and even resistance to antimicrobials. To estimate the annual risk of infection by Salmonella spp. nine different scenarios were designed considering the presence or absence of varying concentrations of Salmonella spp. in soils treated with sewage sludge, the presence or absence of growth of the bacteria in vegetables, the growth inhibition of Salmonella spp. in carrots...

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