Parasite detection in sand from bays on the north coast of São Paulo state, Brazil

Soil contamination by protozoan parasites and soil-transmitted helminths (STH) is common in beach sand due to a number of factors such as pets, pluvial water, garbage, etc. These pathogens may cause many diseases in humans and animals and become a public health problem. Thus, systematic evaluation and inspection are necessary to develop control strategies regarding public contamination. For this purpose, our aims were to evaluate the parasitic profile of sandy soils on an urban beach and an untouched beach and correlate this with environmental and seasonal characteristics in Ubatuba, Brazil, in two seasons (winter and summer). 132 soil samples were collected for parasite analysis utilizing Rugai's method and the sedimentation adapted method. Our results showed positivity in 62% of the samples for at least one parasite in the urban beach and no parasitic structures on the untouched beach. The positivity was higher in summer (85%) than in winter (51.7%). All samples were positive for both, helminths and protozoa. Seasonal influence was noted regarding the presence of STH while for protozoa this influence was not observed. The parasitic structures most found were larvae of hookworms (35%) and Toxocara eggs (31.7%). We also noted the presence of Strongyloides sp, Ascaris lumbricoides, coccidia, Dipylidium caninum, Entamoeba hystolitica/dispar, Endolimax nana, Entamoeba coli, Giardia sp, Toxascaris leonina, Trichuris sp and Dibothricephalus latus. There was a positive correlation between temperature and the presence of STH in the sand samples. Most of the collection sites on the urban beach presented dogs or canine traces and garbage in both seasons. There was an association between the presence of dogs or their traces and parasitic structures. In conclusion, seasonality, urbanization and the presence of pets on beaches can potentially favor environmental contamination by parasites increasing the risk of transmission of zoonotic and parasitic diseases.

Avaliação da eficiência de um índice de estado trófico na determinação da qualidade da água de reservatórios para abastecimento público / Assessment of the efficiency of a trophic state index in determining the water quality of public water supply reservoirs

RESUMO O objetivo deste estudo consiste na avaliação da eficácia do uso de um índice de estado trófico (IET) como ferramenta na análise da qualidade das águas de três reservatórios. O IET foi calculado baseado na transparência do reservatório e nas concentrações de clorofila-a e fósforo total (P total). Para identificar a correlação do uso do solo com a poluição aquática das represas, o IET calculado para cada represa foi comparado ao mapeamento temático de cobertura do solo com base em imagens do satélite Landsat TM 5 do ano de 2010. A análise dos componentes principais (ACP), focada na correlação dos dados, foi realizada utilizando o software PAST®, versão 2.16. Inicialmente, o comportamento dos parâmetros associados ao IET foi avaliado de forma isolada (P total, clorofila-a e transparência) sobre os reservatórios. Em seguida, foram aplicados à ACP os demais parâmetros físicos e químicos associados à qualidade da água dos reservatórios (sem o IET). Por fim, todos os parâmetros foram submetidos à ACP (IET e todos os outros parâmetros em conjunção). O IET utilizado nesta pesquisa demonstrou ser autossuficiente na predição da qualidade de água com a utilização de apenas três parâmetros (P total, clorofila-a e transparência). A análise das imagens de satélite, em conjunto com os dados provenientes do IET, foi suficiente para apontar a redução da qualidade das águas por fontes pontuais de poluição, mesmo em ambientes com maior cobertura vegetal preservada.

ABSTRACT The aim of this study consists in the evaluation of the trophic state index (IET) efficacy as a tool in the water quality analysis of three reservoirs. The IET was calculated based on water transparency in the reservoir and on the surface concentrations of chlorophyll-a and total phosphorus (total P). To identify the correlation of the soil use with the reservoir aquatic pollution, the IET calculated for each reservoir was compared to the thematic mapping of land cover based on Landsat TM 5 satellite images from 2010. The main components analysis (ACP), focused on data correlation, was made using the software PAST®, version 2.16. Initially, the behavior of the parameters associated with the IET was evaluated alone (total P, chlorophyll-a and transparency) on the reservoirs. Then, the other chemical and physical parameters associated with the reservoirs water quality (without the IET) were applied to the ACP. Finally, all the parameters underwent the ACP (IET and all the other parameters in conjunction). The IET used in this research seemed to be self-sufficient in the prediction of water quality using only three parameters (total P, chlorophyll-a and transparency). The satellite images analysis, in conjunction with the IET data, was sufficient to point out the water quality reduction by punctual sources of pollution even in environments with larger preserved vegetal coverage.