Bioassessment of a combined chemical-biological treatment for synthetic acid mine drainage.
In this work, ecotoxicological characteristics of synthetic samples of acid mine drainage (AMD) before and after a combined chemical-biological treatment were investigated by using Lepidium sativum and Daphnia magna. AMD treatment was performed in a two-column apparatus consisting of chemical precipitation by limestone and biological refinement by sulphate reducing bacteria. Synthetic samples of AMD before treatment were toxic for both L. sativum (germination index, G, lower than 10%) and D. magna (100% immobility) due to acid pH and presence of copper and zinc. Chemical treatment (raising pH to 5-6 and eliminating copper) generated effluents with reduced toxicity for L. sativum (G=33%), while 100% immobility was still observed for D. magna. Dynamic trends of toxicity for the first and fifth outputs of the biological column denoted a gradual improvement leading to hormesis for Lepidium (after the initial release of organic excess), while a constant residual toxicity remained for Daphnia (probably due to H(2)S produced by sulphate reducing bacteria).
Pagnanelli
F
F
Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy. francesca.pagnanelli@uniroma1.it
De Michelis
I
I
Di Muzio
S
S
Ferella
F
F
Vegliò
F
F
D000818:Animals; D003621:Daphnia; D004305:Dose-Response Relationship, Drug; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000633:toxicity*; D004787:Environmental Pollution / Q000517:prevention & control; D018525:Germination / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007220:Industrial Waste / Q000009:adverse effects / Q000032:analysis*; D031220:Lepidium sativum; D019216:Metals, Heavy / Q000032:analysis; D008906:Mining; D009043:Motor Activity / Q000187:drug effects; D012037:Refuse Disposal / Q000379:methods*; D018675:Toxicity Tests
D004785:Environmental Pollutants; D007202:Indicators and Reagents; D007220:Industrial Waste; D019216:Metals, Heavy