Uso de águas residuárias tratadas na cultura de hortaliças: avaliação de enteroparasitas e metais pesados / The use of treated residuary water to grow vegetables: assessment of enteroparasites and heavy metals.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Water shortage is a worldwide problem, and the use of residuary water is an important theme regarding the preservation of water bodies and conscious use of the resources available. This study aimed to evaluate the viability of using treated residuary water from the Biological Wastewater Treatment Plant of Ribeirão Preto (ETE-RP) to grow vegetables, through the characterization and quantification of parasites, coliforms and heavy metals. Three equal cultivation areas were prepared in a space given by ETE-RP, the first was irrigated with treated/chlorinated (0.2 mg/L) wastewater, the second with treated wastewater and the third with potable water, which was the control group. Parasitological and bacteriological analyses were carried out in the Environmental Health Laboratory in the University of Sao Paulo at Ribeirao Preto College of Nursing. The Spontaneous Sedimentation Method was used to identify parasites and the P/A Test (Presence or Absence) to investigate bacteria of the coliform group. Parasite count was done in Sedgwick-Rafter Chamber and coliform quantification by the Multiple Tubes Technique. Cd, Cu, Cr, Pb and Zn analyses were carried out by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) at the Institute of Chemistry of São Carlos in the University of Sao Paulo. Hg dosage was done by Hydride Generation Atomic Absorption Spectrophotometry at the Pediatrics Laboratory, in the Metals Unit at Hospital das Clínicas, University of Sao Paulo at Ribeirao Preto Medical School (HCFMRP/USP). The presence of Hymenolepis nana, Enterobius vermicularis, Nematode larvae, Ascaris lumbricóides, Schistosoma mansoni and Entamoeba coli was verified in irrigation waters, with except of potable water. Values found are higher than the limits established by the WHO, which are <1 nematode/L. Results of fecal coliforms in potable water and treated/chlorinated wastewater are within the limits established by CVS (Sanitary Vigilance Center) Decree n.21 from December 19 1991. The presence of thHymenolepis nana, Enterobius vermicularis, Nematode larvae and Entamoeba coli was verified in lettuce samples. Coliform count on vegetables did not show statistically significant difference among the three irrigation types. Levels of heavy metals in vegetable growing soil and in irrigation waters are within the maximum limits allowed by CETESB (2001) and the parameters recommended by EPA (2004), respectively. Concentration of heavy metals in vegetables does not represent significant risks to human health, according with recommended parameters by WHO (1989).

ASSUNTO(S)

ribeirão preto wastewater use reúso de água metals enteroparasitas enteroparasites ribeirão preto metais pesados heavy

ACESSO AO ARTIGO

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