Efficiency of the salt flotation technique in the recovery of Ascaris lumbricoides eggs from the soil.

The efficacy of the salt flotation technique using saturated solutions of sodium nitrate (specific gravity 1.30) and zinc sulphate (specific gravity 1.16) for separating Ascaris lumbricoides eggs from clay, loamy and sandy soils has been investigated. Ten samples of each of the egg concentrations of 100, 500, 2500, 5000 and 10,000 eggs/25 g of soil were used for each soil type. Using T-test and ANOVA, the number of eggs recovered from sand was significantly higher than from loam and the number from loam significantly higher than from clay. With sodium nitrate, the maximum egg recovery rate was 25.04% from sandy soil at a concentration of 500 eggs/25 g soil while with zinc sulphate it was 13.88% also from sandy soil and concentration of 500 eggs/25 g soil. While the number of eggs recovered increased with soil egg concentration, the percentage of eggs recovered is inversely proportional to egg concentration. The number of eggs recovered with sodium nitrate was significantly higher than with zinc sulphate solution in the three soil types.