Poultry litter is one of the main sources of fluoroquinolones (FQs) in agricultural soils. In this study, our main goal was to investigate FQ-contaminated poultry litter effects on Eisenia andrei earthworms. To achieve this, acute and chronic tests covered several endpoints, such as avoidance, biomass, lethality, reproduction and changes to immune cells. FQs (enrofloxacin and ciprofloxacin) were determined in a poultry litter sample through high performance liquid chromatography with a fluorescence detector. The avoidance test indicates that poultry litter strongly repels earthworms, even at the lowest concentration (50 g kg-1). In the acute test, the lethal concentration of poultry litter to 50% of the earthworms (LC50), was estimated at 28.5 g kg-1 and a significant biomass loss (p < 0.05) occurred at 40 g kg-1. In the chronic test, a significant reproduction effect was observed at 20 g kg-1. Cell typing, density and feasibility indicated significant effects ranging from 5 to 20 g kg-1. A high risk quotient was estimated based on recommended poultry litter applications in field studies. Although FQ contamination in poultry litter and soils has been widely reported in previous studies, this is, to the best of our knowledge, the first toxicological assessment concerning earthworms exposed to FQ-contaminated poultry litter.
The objective of the present study was to investigate the reduction of mobility, availability and toxicity found in soil contaminated with lead (Pb) and cadmium (Cd) from Santo Amaro Municipality, Bahia, Brazil using two combined methods, commonly tested separately according to the literature: metal mobilization with phosphates and phytoextraction. The strategy applied was the treatment with two sources of phosphates (separately and mixed) followed by phytoremediation with vetiver grass (Vetiveria zizanioides (L.)). The treatments applied (in triplicates) were: T1—potassium dihydrogen phosphate (KH2PO4); T2—reactive natural phosphate fertilizer (NRP) and; T3—a mixture 1:1 of KH2PO4 and NRP. After this step, untreated and treated soils were planted with vetiver grass. The extraction procedures and assays applied to contaminated soil before and after the treatments included metal mobility test (TCLP); sequential extraction with BCR method; toxicity assays with Eisenia andrei. The soil-to-plant transfer factors (TF) for Pb and Cd were estimated in all cases. All treatments with phosphates followed by phytoremediation reduced the mobility and availability of Pb and Cd, being KH2PO4 (T1) plus phytoremediation the most effective one. Soil toxicity however, remained high after all treatments.