Toxicity identification evaluation of anaerobically treated swine slurry: A comparison between Daphnia magna and Raphanus sativus
Anaerobic digestion does not efficiently reduce ionic compounds present in swine slurry, which could present a potential risk to aquatic ecosystems (surface runoff) and terrestrial ambient (irrigation). The objective of this study was to evaluate the ecotoxicological characteristics of anaerobically treated swine slurry using acute and chronic (epicotyl elongation) toxicity tests with Daphnia magna and Raphanus sativus and identification of suspected toxic compounds using the Toxicity Identification Evaluation (TIE) method. The evaluation was performed in three phases: physicochemical characterization of the slurry; acute/chronic toxicity testing with Daphnia magna and Raphanus sativus for each fraction of the TIE (cation and anion exchange columns, activated carbon, pH modification/aeration and EDTA) and identification of suspected toxic compounds. The anaerobically treated slurry contained concentrations of ammonium of 1,072 mg L-1, chloride of 815 mg L-1 and metals below 1 mg L 1 with a D. magna acute toxicity (48h-LC50) of 5.3% and R. sativus acute toxicity (144h-LC50) of 48.1%. Epicotyl elongation of R. sativus was inhibited at concentrations above 25% (NOEC). The cation exchange reduced the toxicity and free ammonia by more than 90% for both bio-indicators. Moreover, this condition stimulated the epicotyl growth of R. sativus between 10% and 37%. In conclusion, the main compound suspected of causing acute toxicity in D. magna and acute/chronic toxicity in R. sativus is the ammonium. The findings suggest the need the ammonium treatment prior to the agricultural reuse of swine slurry given the high risk to contaminate the aquatic environment by runoff and toxicity of sensitive plants.
|Título según WOS:||Toxicity identification evaluation of anaerobically treated swine slurry: A comparison between Daphnia magna and Raphanus sativus|
|Título según SCOPUS:||Toxicity identification evaluation of anaerobically treated swine slurry: A comparison between Daphnia magna and Raphanus sativus|
|Título de la Revista:||JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART B-PESTICIDES FOOD CONTAMINANTS AND AGRICULTURAL WASTES|
|Editorial:||TAYLOR & FRANCIS INC|
|Fecha de publicación:||2014|
|Página de inicio:||880|