Genotoxicity of concentrate swine and cattle operation facilities effluents before and after geotextile filtration

JAVIER GASULLA; NICOLÁS RIERA; BRIAN J. YOUNG; DIANA CRESPO; PEDRO CARRIQUIRIBORDE

Buenos Aires

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

SETAC-LA

Concentrate animal operations (CAOs) arise as an environmental issue due to the high volume of toxic effluents generated. Geotextil filtration (GF) is a treatment system where solids are coagulated and retained, while liquids are pumped through a tube constructed of synthetic fibers. Dewatering of sludge and effluents by GF was proposed as an adequate primary treatment to reduce toxicity of wastewaters. Ecotoxicological evaluations of agricultural effluents are scarce and usually focused only on mortality assessments. Genetic damage may be induced by very low concentrations of toxic species (i.e. metals) present in complex mixtures like CAOs-derived effluents. The aims of this work were i) to study the genotoxicity of effluents from two different animal sources: a swine farm (SE) and a cattle livestock market (CE), and ii) to evaluate the ability of GF to reduce this toxicity. Comet assays were conducted on blood erythrocytes of the freshwater fish Cnesterodon decemmaculatus acutely exposed (48 hs) to different effluents dilutions. Raw and treated effluents were diluted at two levels, corresponding with their 48h-LC10 and 48h-LC5. Each treatment was tested by quadruplicate using 3 fish per replication. In addition, a negative (dilution water) and a positive (MMS 7.5 mg/L) control groups were included. Percentage of tail DNA (%Tail) and tail moment (TM) were measured using CASP software and compared to negative control. High level of chemical oxygen demand (COD) was measured in CE and fish toxicity was mild (LC50, 96hs = 67.9%). Nevertheless, raw CE produced significant genotoxic effects at LC10 (p100%) was observed in GF treated CE. No significant genotoxic effects were observed in fish exposed to undiluted GF-CE. On the other hand, SE showed a high level of toxicity (LC50, 96hs = 2.2%) and produced a significant increase in genotoxicity parameters at both levels tested. Although, mortality was slightly reduced in GF-SE (LC50, 96hs = 5.7%), genotoxic effects shown a marked reduction of 30.7% and 78.3% for LC10 and LC5, respectively. Moreover, the effects in LC5 were similar to that in the control group. Our results highlights that a genotoxicity biomarker is relevant to assess sublethal effects produced by CAOs-derived effluents on freshwater fish and points out that GF is a useful primary treatment in order to reduce effluent toxicity.