Soil eco-risk assessment using a simple earthworm (Eisenia fetida) qualitative avoidance test: A Romanian case study of five swine farm surroundings

Abstract

The assessment of soil contamination and natural self-purification dynamic soil processes can be accomplished by numerous eco-hygienic and sanitary means without additional pollution. Among these, sublethal earthworm avoidance behavior tests have proven to be most effective. The aim of this case study was to determine the soil pollution risk in five large swine farms in Romania by using an avoidance behavior test as a screening tool with adult specimens of the earthworm Eisenia fetida (ISO 17512-1:2008 qualitative test). Two soil samples were extracted at 100 to 300 m (328 to 984 ft) and 500 to 1,000 m (1,640 to 3,280 ft) distance from each swine farm, and a single sample was taken at 1,300 m (4,265 ft) distance. The results were analyzed statistically using the Anderson-Darling Normality Test (NIST/SEMATECH) and have shown that out of the 11 soil samples, the earthworms strongly avoided (p ≤ 0.005) 4 of them, confirming a potential eco-risk. The majority of the samples avoided by the specimens were collected at the 500 to 1,000 m range. However, the soil sample taken 1,300 m away from the farm showed that, at this distance, the soil had no sign of contaminants, as earthworms preferred the testing soil to the reference sample. In our opinion, this simple assessment, which produces fast and accurate results, should be included in a battery of tests as a helpful early qualitative screening tool in soil contamination assessment procedures to reveal a potential eco-risk.