Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, s...Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, substantial attention has been given to the effects of pesticides on vertebrate species and, to a lesser extent, species of zooplankton. The present study was designed to show that the fission time effective concentration in ciliates is a potential aquatic detection index for environmental monitoring. The ciliate Urostyla grandis was treated with doses of chlorpyrifos and dimethoate. After exposed to the pesticides, the LC_(50)(i.e., concentration that killed 50% of the ciliate cells within 24 h) values were 0.029 mg L^(-1) for chlorpyrifos and 0.0685 mg L^(-1) for dimethoate. The fission time effective concentrations after 168 h of exposure were 0.0075–0.0093 mg L^(-1) for chlorpyrifos and 0.2640–0.2750 mg L^(-1) for dimethoate. These results show that the fission time effective concentration is lower than the LC_(50) value in ciliates, indicating that fission time effective concentration is more suitable than the LC_(50) value for environmental monitoring using ciliates. The effects of chlorpyrifos and dimethoate on ciliate cell ultrastructures included agglutination of chromatin in the macronucleus, protruded and discontinuous macronuclear and micronuclear membranes, loss of integrity of mitochondrial membranes and contents, and abscission and deformation of the adoral zone of membranelles.展开更多
KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and relea...KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and releasing aluminum of four kinds of canons was in the decreasing order Ca2+ >K+ >NH+4 >Na+.The dissolution of aluminum increased with the canon concentration. The adsorption affinity of various soils for aluminum was different. The aluminum in the soil with a stronger adsorption affinity was difficult to be exchanged and released by canons. The Al-F complexes were main species of inorganic aluminum at a low concentration of canons, while Al3+ became major species of inorganic aluminum at a high concentration of canons. The results on the effect of anions indicated that the concentrations of total aluminum, three kinds of inorganic aluminum (Al3+, Al-F and Al-OH complexes) and organic aluminum complexes (Al-OM)when SO2-4 was added into soil suspension were lower than those when Cl- was added. The dissolution of aluminum from soils and the distribution of aluminum forms in solution were edicted by the adsorption of Fon the soil. For soils with strong affinty for F- , the concentrations of the three inorganic aluminum species in soil solution after addition of F- were lower than those after addition of Cl-; but for soils with weak affinity for F- , the concentrations of Al3+ and Al-OM were lower and the concentrations of Al-F complexes and total inorganic aluminum after addition of F- were higher than those after addition of Cl-. The increase of F- concentration in soil solution accelerated the dissolution of aluminum from soils.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 31601866 and 31501844)the Heilongjiang Province Colleges and Universities Youth Innovative Training Program (Nos. UNPYSCT2017178 and 2017180)
文摘Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, substantial attention has been given to the effects of pesticides on vertebrate species and, to a lesser extent, species of zooplankton. The present study was designed to show that the fission time effective concentration in ciliates is a potential aquatic detection index for environmental monitoring. The ciliate Urostyla grandis was treated with doses of chlorpyrifos and dimethoate. After exposed to the pesticides, the LC_(50)(i.e., concentration that killed 50% of the ciliate cells within 24 h) values were 0.029 mg L^(-1) for chlorpyrifos and 0.0685 mg L^(-1) for dimethoate. The fission time effective concentrations after 168 h of exposure were 0.0075–0.0093 mg L^(-1) for chlorpyrifos and 0.2640–0.2750 mg L^(-1) for dimethoate. These results show that the fission time effective concentration is lower than the LC_(50) value in ciliates, indicating that fission time effective concentration is more suitable than the LC_(50) value for environmental monitoring using ciliates. The effects of chlorpyrifos and dimethoate on ciliate cell ultrastructures included agglutination of chromatin in the macronucleus, protruded and discontinuous macronuclear and micronuclear membranes, loss of integrity of mitochondrial membranes and contents, and abscission and deformation of the adoral zone of membranelles.
文摘KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and releasing aluminum of four kinds of canons was in the decreasing order Ca2+ >K+ >NH+4 >Na+.The dissolution of aluminum increased with the canon concentration. The adsorption affinity of various soils for aluminum was different. The aluminum in the soil with a stronger adsorption affinity was difficult to be exchanged and released by canons. The Al-F complexes were main species of inorganic aluminum at a low concentration of canons, while Al3+ became major species of inorganic aluminum at a high concentration of canons. The results on the effect of anions indicated that the concentrations of total aluminum, three kinds of inorganic aluminum (Al3+, Al-F and Al-OH complexes) and organic aluminum complexes (Al-OM)when SO2-4 was added into soil suspension were lower than those when Cl- was added. The dissolution of aluminum from soils and the distribution of aluminum forms in solution were edicted by the adsorption of Fon the soil. For soils with strong affinty for F- , the concentrations of the three inorganic aluminum species in soil solution after addition of F- were lower than those after addition of Cl-; but for soils with weak affinity for F- , the concentrations of Al3+ and Al-OM were lower and the concentrations of Al-F complexes and total inorganic aluminum after addition of F- were higher than those after addition of Cl-. The increase of F- concentration in soil solution accelerated the dissolution of aluminum from soils.
