Investigation Of Fish Resources And Analysis Of Nutrients And Heavy Metals In The Sanggan River

In this paper,in order to know the fish resources in Sanggan River and the contents of nutrients and heavy metals in fish,5 sampling cross-sections were selected in Sanggan River Basin.National standards were used to detect the contents of conventional nutrients and heavy metals in the catches.Through statistical analysis,the current situation of fish resources,the nutritional components,the content of heavy metals and the pollution degree in fish muscles were obtained.The results showed that:(1)In this survey,there were 9 species in catches,belonging to 9genera,4 families and 2 orders,with a total of 1198 catches.Among them,Cypriniformes were the most,with a total of 7 species,accounting for 77.7%of the total species,and Perciformes include 2 kinds,accounting for 22.3%of the total species.Among them,6 species belonged to Cyprinidae,accounting for 66.7% of the total species.Cobitidae,Gobiidae and Channidae accounted for 11.1% of the total species,respectively.(2)The fauna division of catches is mainly composed of river-plain faunal complex and late tertiary early faunal complex,accounting for71.28% of the total catches;in the ecological type,the spawning way was mainly composed of demersal egg and adhesive egg,there were 8 species of fish distributed in the bottom or lower middle layer of the water body,and the feeding type was mainly omnivorous fish;the relationship between body length and body weight showed that Abbottina rivularis,Cyprinus carpio,Ctenopharyngodon idellus grew at different speed,Carassiusauratus and Pseudorasbora parva grew at the same speed;the dominant species were,Abbottina rivularis,Ctenopharyngodon idellus Carassiusauratus and Pseudorasbora parva,the main species were Ctenogobius giurinus,Oriental weatherfish,Cyprinus carpio,and Hypophthalmichthys molitrix,and the general species was Ophiocephalus argus.(3)The conventional nutrients in the back muscle of the catches wereas follows: water content ranged from 76.48% to 81.3%,protein content ranged from 15.8% to 19.5%,the highest crude fat content of Hypophthalmichthys molitri in the catches reached 5.54%,the lowest crude fat content of Pseudorasbora parva was 1.4%,and ash content ranged from1.12% to1.64%.(4)The total amino acids of 9 species of fish ranged from 12.44 to18.99(g/100g),the essential amino acids ranged from 4.85 to 7.73(g/100g),the fresh amino acids ranged from 4.57 to 7.09(g/100g),the WEAA / WTAA(%)of 9 species of fish ranged from 39% to 43.22%,and the WEAA/ WNEAA(%)ranged from 63.89% to 72.58%.According to the data of AAS,the essential amino acids score ranged from 0.73 to 2.01,and according to the data of CS,the chemical score of freshwater fish ranged from 0.46 to 1.43,which was consistent with the ideal model of FAO / WHO.(5)The results showed that the contents of heavy metals in the back muscles of 9 species of fishes were lower than the national limit standards,Zn: 5.913-20.113 mg/kg,Pb: 0.025-0.209 mg/kg,Cd: 0.004-0.053 mg/kg,As: 0.013-0.090 mg/kg,Hg: 0.017-0.055 mg/kg.(6)The single factor pollution indexes of heavy metals in fishes from Sanggan River were as follows from high to low: As(Pi= 0.558)>Cd(Pi=0.296)> Pb(Pi= 0.239)> Zn(Pi= 0.226)> Hg(Pi= 0.071),and the comprehensive pollution indexes of heavy metals in 9 species of fishes was less than 1,which belonged to the pollution-free level,but the comprehensive pollution indexes of Cyprinus carpio,Ophiocephalus argus,and Ctenogobius giurinus were relatively high.The potential risk of heavy metal pollution was high.The comprehensive pollution indexes of heavy metals in catches were as follows from high to low: Cyprinus carpio >Ctenogobius giurinus>Ophiocephalus argus >Ctenopharyngodon idellus>Carassiusauratus>Oriental weatherfish> Hypophthalmichthys molitrix> Pseudorasbora parva > Abbottina rivularis;but the total target hazard quotient(TTHQ)of the 9 species of fishes was as follows from high to low:Ophiocephalus argus > Carassiusauratus > Cyprinus carpio > Oriental weatherfish > Abbottina rivularis > Ctenogobius giurinus >Hypophthalmichthys molitrix>Pseudorasbora parva = Ctenopharyngodon idellus.However,the TTHQ values of the 9 species of fishes were all less than 1,and the potential health risks of fish exposed to heavy metals were small after eating.