Individual and combined effects of herbicide tribenuron-methyl and fungicide tebuconazole on soil earthworm Eisenia fetida

Abstract

Earthworms are soil engineers that alter the soil bio-physical properties to favor plant growth whereas pesticides represent a significant threat to their abundance and soil health. Thus, we investigated the toxic effects of tribenuron-methyl (TBM) and tebuconazole (TEB) on the soil earthworm, Eisenia fetida. The TBM demonstrated low toxicity to E. fetida in the contact filter paper and artificial soil tests, with median lethal concentrations (LC50) of 135.6 μg cm−2 at 48 h and 511 mg kg−1 on day 14, respectively. Similarly, TEB also showed low toxicity to E. fetida in the artificial soil test with LC50 of 287 mg kg−1 on day 14. However, TEB was highly toxic to earthworm in the contact filter paper test with LC50 of 5.7 μg cm−2 at 48 h. The mixture of two pesticides had an antagonistic effect on the earthworm. Under 0.1 LC50 of TBM and TEB, either single or combined application of pesticides induced oxidative stress and inhibited cellulase activity in early days of the earthworm exposure. However, both pesticides did not damage the earthworm DNA. Our results suggest that pesticides can negatively affect soil earthworms and provide valuable information regarding the responses of soil biological engineers to the lethal agrochemicals.

Continuous Cropping Alters Multiple Biotic and Abiotic Indicators of Soil Health

“…They play a major role in improving the soil conditions, such as breakdown of organic substance, soil aggregation, aeration, nutrient cycling and sequestration, microbial community composition, and functioning [151,152]. Meanwhile, earthworms are considered to be sensitive to the climatic conditions [153], soil moisture, organic matter [154,155], physicochemical properties [156], nutrient resources [157], heavy metals [158], organic pollutants [159,160], and trophic interactions (predation) [161]. The repeated tillage practices under CC may also affect their abundance and functioning in the agricultural soils [162].…”

Assessment of acute toxicity and biochemical responses to chlorpyrifos, cypermethrin and their combination exposed earthworm, Eudrilus eugeniae

“…Earlier reports indicate that application of pesticides pose threat to their lives as they are exposed to pesticides contaminated soil [4]. They are much more susceptible and sensitive to the soil pollutants as compared to other soil inhabitants [5]. Therefore, earthworms are considered most suitable organisms for studying the impact of pesticides on their stress related biochemical parameters.…”

Biotransformation of chlorothalonil by strain Stenotrophomonas acidaminiphila BJ1 isolated from farmland soil

“…However, further research is required to test the toxicity of the two metabolic products on some soil non-target organisms (e.g. earthworms) [42].…”