RESUMO
The effects of single and combined pollution of enrofloxacin and Cu on the digestive enzymes of earthworms were studied, based on the actual pollution of caused by the application of livestock feces in farmland soil. Results showed that single enrofloxacin (0.1-4 mg·kg-1, 28 d) did not affect protease, but inhibited cellulase and alkaline phosphatase, with an induced effect on acid phosphatase. Single Cu pollution (20-200 mg·kg-1, 28 d) had inhibitory effects on the four digestive enzymes in earthworms. The effects of combined exposures on the digestive enzymes were mainly negative, showing a synergistic increasing character of toxicity in cellulase and acid phosphatase activities. The response dynamics of digestive enzymes to exposure duration was regulatory response (3 d)-intense response (7 d)-reaction recovery (14 d)-chronic exposure (28 d). Chronic exposure results showed that the combined treatments containing high-dose pollutant (200 mg·kg-1 Cu or 4 mg·kg-1 ENR) had more ecological risk.
