Background:A germicide like Izal is chemical agent used for reducing and preventing microbial loads in systems for treating water as well as other industries like agriculture and aquaculture.The environmental impact o...Background:A germicide like Izal is chemical agent used for reducing and preventing microbial loads in systems for treating water as well as other industries like agriculture and aquaculture.The environmental impact of germicide is often more than the target intended by those who use them.The purpose of the current study was to ascertain the toxicity levels and behavioral alterations of Juvenile African catfish,Clarias gariepinus,subjected to Izal exposure.Methods:The stock solution was created from the 100 mL by mixing 1 mL of the Izal with 99 mL of water.After that,different nominal concentrations of Izal were prepared using the stock solution by diluting the toxin with tap water in determined amounts(10 L).The fish were exposed to acute concentrations of 1.0,1.5,2.0,2.5 and 3.0 mg/L of Izal had a control that served as a reference point.Results:The lethal concentration of Izal(24 h LC50)was found to be 2.4136 mg/L(95%confidence interval=2.1707–2.6838)for test fish under a semi-static system showing that Izal is moderately poisonous to the species in a dose-dependent manner and time(duration).The highest mortality was recorded in the highest concentration(3.0 mg/L)of Izal while the least mortality was observed in the 1.5 mg/L group.Izal-exposed fish had aberrant behavior,including hyperactivity,gasping of air,respiratory distress,attempts to jump out of the water,erratic swimming,refusal to feed,lethargic movement,and slow response to feed,loss of balance and depigmentation.The severity of the abnormal behavior decreased after 24 h,but remained mildly to moderately high at 2.0 and 2.5 mg/L of Izal.It was found that the death rate increased with Izal concentration and duration.Conclusion:The present study revealed that Izal was moderately toxic to Claris gariepinus juveniles and should be used prudently in the environment to guard against toxicological effect on non-target organisms such as fish.For this reason,the use of the germicides should be with caution especially near water bodies.展开更多
Earthworms as test animats,were exposed in different concentrations of two pesticides:1 (6 chloro 3 pyridinylmthyl) N nitromidazoliding 2 ylideneamin and 2′benzoyi 1′ tert butylbenzoylhydrazinc.The acute toxicity of...Earthworms as test animats,were exposed in different concentrations of two pesticides:1 (6 chloro 3 pyridinylmthyl) N nitromidazoliding 2 ylideneamin and 2′benzoyi 1′ tert butylbenzoylhydrazinc.The acute toxicity of these two pesticides was measured as median lethal concentration values(LC 50 ) of earth worms.Tests of three different exposure systems were performed:the comact filter paper bioassay,the immersion bioassay and the artificial soil bioassay.The results indicated that the two new type pesticides showed vaious toxic effects through different exposure paths .The LC 50 of 1 (6 chloro 3 pyridinymethyl) N nitromidazolidin 2 ylideneamine was 0.034 ug·cm 2 for 48hr filter paper test,0.77mg·ml -1 for 48hr inmersion test and 2.3mg·kg -1 for 14d artiflcial soil test,respectively; while the 2′ benzoy 1′tert butylbenzoylhydrazine was>480 μg·cm -2 for 48hr filter paper test. 2655 mg·ml -1 for 48hr immersion test,and>10000mg·kg -1 for 14d artificial soil test,respectively.These outcome led to a conelusion that 1 (6 chloro 3 pyridinylmethyl) N nitromidazolidin 2 ylideneamine was far more toxic than 2′ benzoyl 1′tert butylbenzoylhydrazine with regard to acute toxicity to earthworm.However,the comprehensive assessment of the influence of both the two pesticides to soil ecosystem could not be made only by acute toxic tests because we were not aware of the mechanism acted on organisms.展开更多
文摘Background:A germicide like Izal is chemical agent used for reducing and preventing microbial loads in systems for treating water as well as other industries like agriculture and aquaculture.The environmental impact of germicide is often more than the target intended by those who use them.The purpose of the current study was to ascertain the toxicity levels and behavioral alterations of Juvenile African catfish,Clarias gariepinus,subjected to Izal exposure.Methods:The stock solution was created from the 100 mL by mixing 1 mL of the Izal with 99 mL of water.After that,different nominal concentrations of Izal were prepared using the stock solution by diluting the toxin with tap water in determined amounts(10 L).The fish were exposed to acute concentrations of 1.0,1.5,2.0,2.5 and 3.0 mg/L of Izal had a control that served as a reference point.Results:The lethal concentration of Izal(24 h LC50)was found to be 2.4136 mg/L(95%confidence interval=2.1707–2.6838)for test fish under a semi-static system showing that Izal is moderately poisonous to the species in a dose-dependent manner and time(duration).The highest mortality was recorded in the highest concentration(3.0 mg/L)of Izal while the least mortality was observed in the 1.5 mg/L group.Izal-exposed fish had aberrant behavior,including hyperactivity,gasping of air,respiratory distress,attempts to jump out of the water,erratic swimming,refusal to feed,lethargic movement,and slow response to feed,loss of balance and depigmentation.The severity of the abnormal behavior decreased after 24 h,but remained mildly to moderately high at 2.0 and 2.5 mg/L of Izal.It was found that the death rate increased with Izal concentration and duration.Conclusion:The present study revealed that Izal was moderately toxic to Claris gariepinus juveniles and should be used prudently in the environment to guard against toxicological effect on non-target organisms such as fish.For this reason,the use of the germicides should be with caution especially near water bodies.
文摘Earthworms as test animats,were exposed in different concentrations of two pesticides:1 (6 chloro 3 pyridinylmthyl) N nitromidazoliding 2 ylideneamin and 2′benzoyi 1′ tert butylbenzoylhydrazinc.The acute toxicity of these two pesticides was measured as median lethal concentration values(LC 50 ) of earth worms.Tests of three different exposure systems were performed:the comact filter paper bioassay,the immersion bioassay and the artificial soil bioassay.The results indicated that the two new type pesticides showed vaious toxic effects through different exposure paths .The LC 50 of 1 (6 chloro 3 pyridinymethyl) N nitromidazolidin 2 ylideneamine was 0.034 ug·cm 2 for 48hr filter paper test,0.77mg·ml -1 for 48hr inmersion test and 2.3mg·kg -1 for 14d artiflcial soil test,respectively; while the 2′ benzoy 1′tert butylbenzoylhydrazine was>480 μg·cm -2 for 48hr filter paper test. 2655 mg·ml -1 for 48hr immersion test,and>10000mg·kg -1 for 14d artificial soil test,respectively.These outcome led to a conelusion that 1 (6 chloro 3 pyridinylmethyl) N nitromidazolidin 2 ylideneamine was far more toxic than 2′ benzoyl 1′tert butylbenzoylhydrazine with regard to acute toxicity to earthworm.However,the comprehensive assessment of the influence of both the two pesticides to soil ecosystem could not be made only by acute toxic tests because we were not aware of the mechanism acted on organisms.
