Traditional seed pretreatment methods cause secondary pollution for the application of various chemicals. This study investigated the effect of dielectric barrier discharge (DBD) cold plasma on seedling growth. Effects of plasma-activated tap water (PATW) and plasma-activated seeds (PAS) were compared for germination rates, seedling height, dry weight, and chlorophyll content. Results show that compared with controls these growth parameters were all increased by more than 50%. The yields and contributions of hydrogen peroxide, nitrate, nitrite, and ammonium were quantified. Hydrogen peroxide and nitrate have an important role in seedling growth. By etching, the seed epidermis free radicals can reduce the apparent contact angle and increase the water absorption of the seeds. In addition to the low cost of PATW and PAS compared with commercial fertilizers, DBD does not involve any chemical addition. Thus, both PATW and PAS can be an alternative for improvement of agricultural production.

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Glucocorticoids (GCs) have drawn great concern due to widespread contamination in the environment and application in treating COVID-19. Most studies on GC removal mainly focused on aquatic environment, while GC behaviors in soil were less mentioned. In this study, degradation of three selected GCs in soil has been investigated using citric acid (CA)-modified Fenton-like processes (H 2 O 2 /Fe(III)/CA and CaO 2 /Fe(III)/CA treatments). The results showed that GCs in soil can be removed by modified Fenton-like processes (removal efficiency gt; 70% for 24 h). CaO 2 /Fe(III)/CA was more efficient than H 2 O 2 /Fe(III)/ CA at low oxidant dosage (< 0.28-0.69 mmol/g) for long treatment time (> 4 h). Besides the chemical assessment with GC removal, effects of Fenton-like processes were also evaluated by biological assessments with bacteria and plants. CaO 2 /Fe(III)/ CA was less harmful to the richness and diversity of microorganisms in soil compared to H 2 O 2 /Fe(III)/CA. Weaker phytotoxic effects were observed on GC-contaminated soil treated by CaO 2 /Fe(III)/CA than H 2 O 2 /Fe(III)/CA. This study, therefore, recommends CaO 2 -based treatments to remediate GC-contaminated soils. Keywords Glucocorticoid degradation . Fenton-like processes . CaO 2 oxidation . Soil remediation . Microbial communities . Phytotoxic effects Highlights • H 2 O 2 -and CaO 2 -based oxidation can effectively remove GCs from soils. • CaO 2 -based oxidation was more efficient than H 2 O 2 at low oxidant dosage. • CaO 2 -based oxidation was less harmful to soil microorganisms than H 2 O 2 . • H 2 O 2 -based oxidation showed stronger phytotoxic effect than CaO 2 .

Glucocorticoids (GCs) have drawn great concern due to widespread contamination in the environment and application in treating COVID-19. Most studies on GC removal mainly focused on aquatic environment, while GC behaviors in soil were less mentioned. In this study, degradation of three selected GCs in soil have been investigated using citric acid (CA)-modified Fenton-like processes (H2O2/Fe(III)/CA and CaO2/Fe(III)/CA treatments). The results showed that GCs in soil can be removed by modified Fenton-like processes (removal efficiency > 70% for 24 h). CaO2/Fe(III)/CA was more efficient than H2O2/Fe(III)/CA at low oxidant dosage (< 0.28–0.69 mmol/g) for long treatment time (> 4 h). Besides the chemical assessment with GC removal, effects of Fenton-like processes were also evaluated by biological assessments with bacteria and plants. CaO2/Fe(III)/CA was less harmful to the richness and diversity of microorganisms in soil compared to H2O2/Fe(III)/CA. Weaker phytotoxic effects were observed on GC-contaminated soil treated by CaO2/Fe(III)/CA than H2O2/Fe(III)/CA. This study therefore, recommends CaO2 based treatments to remediate GC-contaminated soils.