Helminth eggs as parasitic indicators of fecal contamination in agricultural irrigation water, biosolids, soils and pastures

Abstract

Introduction: A very common practice in agriculture is the disposal of wastewater and biosolids from water treatment systems due to their high nutrient content, which substantially improves crop yields. However, the presence of pathogens of fecal origin creates a sanitary risk to farmers and consumers. Objective: To determine the presence and concentration of helminth eggs in irrigation waters, biosolids, agricultural soils, and pastures. Materials and methods: Water, biosolids, soil, and pasture samples were collected and analyzed for helminth egg detection, total eggs and viable eggs counts. The behavior of helminth eggs was evaluated in irrigation waters and dairy cattle grassland, where biosolids had been used as an organic amendment. Results: Concentrations between 0.1-3 total helminth eggs/L, and 0.1-1 viable helminth eggs/L were found in water. In biosolids and soil, we found 3-22 total helminth eggs/4 g of dry weight, and 2-12 viable helminth eggs/4 g of dry weight, and in grass, we found <2-9 total helminth eggs/g of fresh weight, and <1-3 viable helminth eggs/g of fresh weight. The presence of helminth eggs in each matrix varied from days to months, which may represent a sanitary risk to farmers as well as to consumers. Conclusions: The presence of helminth eggs in the assessed matrixes confirms the sanitary risk of such practices. Therefore, it is important to control and incorporate regulations related to the use of wastewater and biosolids in agriculture.

Keywords

• Helminths
• pollution indicators
• waste water
• health risk
• agricultural zones