Toxicity Evaluation Of Water Pollution Of Baiyin Section Of The Yellow River Using The Peripheral Blood Cells Of Carassius Auratus

In recent years, with the fast development of industry and agriculture and the rapid increase of the population, plenty of industrial sewage and domestic sewage was poured into the Yellow River without effective control, at the same time, there were prevalent phenomena in the upstream of the Yellow River, such as water loss, soil erosion and discharging back of irrigating water, which caused serious pollution of Baiyin Section of the Yellow River (BSYR). The paper mainly evaluated the effect of water pollution on the peripheral blood cell of Carassius auratus. The Reservoir Liujiaxia (RL) was devoid of any industry and had been reported to carry relatively little toxic substance, so it could be considered as a control between two sites under study. Some relative parameters like the number of erythrocytes and leucocytes, erythrocyte micronuclei and nuclear abnormalities, counts on various leucocytes, the size of erythrocytes and so on were assessed to strengthen the basis for the research. The results were as follows:Compared to RL, in BSYR, the number of erythrocytes decreased in the three months (December in 2005, April and June in 2006) and reached the significant level (P<0.05) in December and April; Total number of leucocytes had the tendency to increase in the three months but reached the significant level only in April (P<0.05). The counting results showed that the number of lymphocytes had the tendency to increase in general, however reached the significant level only in June (P<0.05); Neutrophil numbers were significantly decreased (P<0.05) in the three months except in June (P>0.05); and yet thrombocyte numbers were obviously increased in the three months but did not reach the significant level (P>0.05) in April; Monocyte numbers had no regular changes in the three months between the two studied areas. Thus, the number of peripheral blood cells was altered by the polluted water in BSYR.The frequencies of erythrocyte micronuclei (P<0.05) were significant higher in BSYR than that in RL in the three months; The frequencies of nuclei abnormalities and total nuclei abnormalities were increased in the three months but reached to significant level only in April (P<0.05). The results showed that the water in BSYR had been causing the genotoxity to the C. auratus.Comparative analysis of C. auratus erythrocytes and nuclei size showed that the short diameter of nuclei and cells became shorter, and the ratio of the long diameter of nuclei and cells was diminished in BSYR compared to RL. And all parameters showed that the shape of erythrocytes had been affected by the polluted water in BSYR.Observation on C. auratus morphological characteristics showed that the ratio of head length and total length was increased, but the ratio of tail length and total length and the ratio of body weight and total length were decreased. And from comparing the organ index between the two sites, the results showed that spleen index, kidney index and head kidney index were much lower but the gonad index was much higher in BSYR than that in RL. Thus, the results suggested that the long period and low-concentration contamination of the BSYR had been causing the form and important immune organ indexes of C. auratus changed, thus likely to affect the immune and hematopoietic function of the fish, at the same time, that might be the signal that the body of C. auratus had somewhat adaptive alterations to protect against the water pollution.In conclusion, the contamination at environmental level in BSYR had been causing obvious toxic effects to the peripheral blood cells and forming potential threat to the physiological function of C. auratus. In addition, the results demonstrated that the pollution of BSYR was rather serious, it was necessary to strengthen monitoring, prevention and cure to protect the water resource of the Yellow River.