Effects of salinity on earthworm (Eisenia fetida)

Abstract

Road salts negatively affect environment ecosystems. Sodium chloride (NaCl) from runoff is responsible for the increased salinity of soil surface and ground waters. The aim of the study was to assess the effects of salinity on earthworm Eisenia fetida growth, reproduction and survival. To achieve this, experiment was conducted using OECD artificial soil spiked with NaCl (0, 1000, 2000, 4000, 6000 and 8000 mg NaCl kg-1). Growth was assessed at day 7, 14, 28, mortality and cocoon production - at day 56. Total mortality of worms was found in 6000 mg NaCl kg-1 and 8000 mg NaCl kg-1 tests. The calculated LC50 for mortality after 28 days was 5623 mg NaCl kg-1. Weight of worms was significantly affected by NaCl. Dispersion analysis showed that NaCl concentration had statistically significant influence on weight of worms (P < 0.05). The calculated EC50 (effect concentration at which a 50 % reduction in a measured parameter) for growth was 2512 mg NaCl kg-1. Cocoon production was significantly affected by increased NaCl substance. There was no cocoon production in soil with 4000 mg NaCl kg -1 and higher concentrations. It is concluded that sodium chloride negatively effects lifecycle of earthworms. It is essential to find less toxic de-icers on purpose to ensure transport safety.