Analysis of bacteria, parasites, and heavy metals in lettuce (Lactuca sativa) and rocket salad (Eruca sativa L.) irrigated with treated effluent from a biological wastewater treatment plant.
This study aimed to evaluate the viability of using treated residuary water from the Biological Wastewater Treatment Plant of Ribeirão Preto to grow vegetables, through the characterization and quantification of parasites, coliforms, and heavy metals. Three equal cultivation areas were prepared. The first was irrigated with treated/chlorinated (0.2 mg L(-1)) wastewater, the second one with treated wastewater without chlorination, and the third site with potable water, which was the control group. The presence of Hymenolepis nana, Enterobius vermicularis, nematode larvae, and Entamoeba coli was verified in lettuce (Lactuca sativa) samples. Although nematode larvae were observed in rocket salad (Eruca sativa L.), no significant differences were found between the number of parasites and type of irrigation water used. No significant differences were found between the number of fecal coliforms in vegetables and the different types of irrigation. However, the vegetables irrigated with treated effluent without chlorination showed higher levels of fecal coliforms. The risk of pathogens is reduced with bleach addition to the treated effluent at 0.2 mg/L. Concentration of heavy metals in vegetables does not mean significant risks to human health, according with the parameters recommended by the World Health Organization.
Nikaido
Meire
M
Maternal Infant Nursing and Public Health Department, University of São Paulo, WHO Collaborating Centre for Nursing Research Development, Ribeirão Preto, Brazil.
Tonani
Karina A A
KA
Julião
Fabiana C
FC
Trevilato
Tânia M B
TM
Takayanagui
Angela M M
AM
Sanches
Sérgio M
SM
Domingo
José L
JL
Segura-Muñoz
Susana I
SI
D018545:Lactuca / Q000737:chemistry / Q000382:microbiology / Q000469:parasitology; D019216:Metals, Heavy / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D019216:Metals, Heavy; D014874:Water Pollutants, Chemical