Distribution And Edible Risk Assessment Of Cadmium, Lead In Main Economic Fishes From Dongting Lake,China

Fish is one of the major aquatic for human consumption, which is very popular because the high-quality protein and the higher nutritional value. Now, with the pollution of heavy metals in water environment is worsening, more and more people attention to the heavy metals contamination in fishes. Heavy metal contamination in fishes will not only cause harm to the fish itself, but also have some impacts on the aquatic ecosystem and environmental safety and the healthy development of freshwater fisheries. Contaminated fish may through the food chain to transfered the heavy metals to humans, and resulting in a serious threat to people’s health and consumer safety. Therefore, in order to protect the safety of fish-eating consumers and healthy development of the fisheries, it is particularly important to analysis the heavy metals accumulations and the fish contamination levels and the health risk assessment of humans intake the heavy metals by fish-eating and the edible safety evaluation offish.In this study, we used six major economic fish species including grass carp (Ctenopharyngodon idella),bream (Parabramis pekinensis),carp (Cyprinus carpio), alburnus(Erythroculter ilishaeformis), snakehead (Channa argus) and mandarin(Siniperca chuatsi) as the research object, which were collected at Dongting Lake from September 2014 to March 2015. Using wet digestion method for sample pretreatment, the heavy metal cadmium (Cd) and lead (Pb) contents (in terms of wet weight) in different fish tissues were determined respectively by graphite atomic absorption spectrometry (GF-AAS) and flame atomic absorption spectrometry (AAS). The contents distribution of Cd, Pb between the various tissues and species, and the characteristic of spatial distribution were analyzed. In addition, Analyzed the influence of Cd, Pb accumulations on fish by feeding habits, body length, body weight and other factors. The method of single factor pollution index, PTWI and THQ were used to evaluate the pollution degree, edible security and health risk. The results as follows:(1) The Cd, Pb concentrations varied with fish species. Heavy metals (Cd, Pb) contents did not exceed the national limit standard and in the security edible range which detected in fish muscle tissue. The accumulations of Cd, Pb are significant difference in different organizations which were detected (p< 0.05). The Cd, Pb concentrations varied in the same organization (Pb> Cd). Except the concentrations of Cd, Pb is relatively higher in the scale and the skin in fewer fish, most fish are mainly concentrated in the hepatopancreas and intestine, while the concentrations reached the lowest levels in muscle.(2) In some extent, the accumulations of Cd, Pb in fish was affected from feeding habit, habitat, the difference in length and weight and the seasonal changes. There is a certain biomagnifications in addition to the muscle tissues which were detected, the concentrations of Pb in fishes are:omnivorous> herbivorous> carnivorous, the rest as follows:carnivorous> omnivorous> herbivorous. The accumulations of Cd, Pb in pelagic fish and demersal fish is relatively higher than the herbivorous fish which living in the middle and lower. There is a certain positive correlation between the accumulations of Cd, Pb and body length and body weight in different fish and tissues. The contents of Cd, Pb in autumn are higher than spring.(3) The Cd, Pb accumulations in fishes from different sampling sites showed certain spatial difference. Comparative analysis the spatial distribution of Cd, Pb contents on the parameters of the Cd, Pb average accumulated amount in four fishes which are grass carp, bream, carp, alburnus. The results as follow:the spatial distribution characteristics of Cd in fishes is:Chenglingji= East Dongting Lake> West Dongting Lake; the spatial distribution characteristics of Pb in fishes is:Chenglingji> East Dongting Lake> West Dongting Lake. Comparative analysis the spatial distribution of Cd, Pb contents on the parameters of the Cd, Pb accumulated amount in carp muscle. The results as follow:the distribution characteristics of Cd in fishes is:Chenglingji> Lujiao> Yueyanglou> Junshan> Leijiazui> Jiangjiazui> Dalianzhang; the spatial distribution characteristics of Pb in fishes is:Lujiao> Chenglingji> Yueyanglou> Junshan> Leijiazui> Jiangjiazui> Dalianzhang.(4) The Cd, Pb contamination levels in fish muscle which were detected from Dongting Lake is:Pb> Cd. The pollution levels of sampling regions is Chenglingji> East Dongting Lake> West Dongting Lake. There is a varying degrees of pollution levels in fish tissues from different regions, except muscle tissues (Pi< 0.2).(5) The Target Hazard Quotients (THQ) of Cd and Pb in muscle was less than 1, and the Estimated Weekly Intake (EWI) was far below the Provisional Tolerable Weekly Intake (PTWI), which indicates the risks for the general population consumption is lower in Dongting Lake. Respective to arrange the health risk assessment of six fish tissues, the Target Hazard Quotients (THQ) of Cd and Pb in each tissue was less than 1. But the Cd accumulations of intestine and hepatopancreas in bream, carp, alburnus, snakehead and the Pb accumulations of hepatopancreas in snakehead, the ratio of EWI accounted PTWI was higher than 10%. Therefore, can be considered that when eat amount of intestine of fishes (carp, alburnus) may have some security risks.