2.1 Test organisms
Chironomus striatipennis Kieffer were cultivated and maintained under optimal conditions in the water ecological restoration Laboratory of Shanghai Ocean University. Organisms were reared in a glass chamber containing fine inorganic sediment (<10 mm), under a 16-hour light to 6-hour dark cycle and constant aeration. The water temperature was maintained at 25 ± 1 ℃. The yeast extract solution (CAS Number: 8013-01-2 from Macklin) was provided as food every day.