Safety Assessment Of Different Arsenic Species In Aquatic Organisms

Accumulation and depuration of arsenic in Carassius auratus and Philippinarum Ruditapes were discovered, the content of arsenic species and other heavy metals in samples from coastal areas of China were analyzed. The genetic toxicity of arsenic with different valence and the rapid determination of trivalent arsenic (As³⁺) were also studied.Accumulation and depuration of arsenic in Carassius auratus and Philippinarum Ruditapes were studied in arsenic solution with different concentration. A 35- days experiment of Carassius auratus was conducted to compare the accumulation, depuration, and toxicological effects on AChE forced with 5mg/kg, 10mg/kg, 20mg/kg arsenic solution. Total concentration of arsenic accumulated reached 5.09 mg/kg, 8.64 mg/kg, 23.57mg/kg (dry weight) in exposure time respectively, while a few of arsenic could be excreted when treated with clean-water for 10 days and the decrease trend of AChE activity also be observed. Exposure time of Philippinarum Ruditapes in 5mg/kg, 10mg/kg, 20mg/kg arsenic solution was 30h and then depuration time was also 30h, it could be found that BCF of Philippinarum Ruditapes were 1.66, 1.135, 0.605 and B_1/2 were 0.55d, 0.7d, 0.97d respectivelyoCopper, cadmium, lead, mercury and arsenic in aquatic samples that collected from coastal areas of China were analyzed. It could be observed that the problem of arsenic pollution was not serious, inorganic arsenic in all samples were not over limited ( GB18406.4-2001) , The content of Cu, Cd, Pb, Hg did not show any influence to the accumulation of arsenic in aquatic organisms. The different arsenic species in aquatic samples were separated with extraction and were detected with ICP-AES. It could be found that organic arsenic were dominant species in total arsenic,Arsenosugar was the most important arsenic compound in alga, monomethylarsonic(MMA) was not found in alga; dimethylarsinic acid(DMA), arsenobetaine(AsB) , arsenochline(AsC) and other organic arsenic compounds occupied about 80% in total arsenic of fish and shellfish samples, but the content of arsenosugar and MMA was few.The inhibitory of arsenic (As3+) and arsenate(As5 + ) on brain AChE from eight kinds of fishes were studied. It could be found that the AChE activity of Sabasdotes fuscescens, Scomberomorus niphonius and lateolabrax japonicus had a good linear correlation with -lg[As3+] when the concentration of As3+ from 10⁴mol/L to 10⁶mol/L(R>0.97); It could be conclude from IC50 that the sensitive order of AChE to As3+: sciaenops ocellatus> Ctenopharyngodenidellus, Carassius auratus, lateolabrax japonicus> Sabasdotes fuscescens, Scomberomorus niphonius> Cyprinus carpio, hypophthal michthys molitrix. when the concentration of inorganic arsenic from 10⁶mol/L to 10⁴mol/L, a great significant could be found between the inhibitory rate of As3+ and As5+ (p<0.01) on eight kinds of brain acetylcholinesterase. The inhibitory rate of As3+ was far more than As5+on AChE.A simple, sensitive, rapid and reliable method has been developed for spectrophotometric determinations of As +, The method allows the determination of arsenic in the range of 20 u g/L¹000u g/L,the relative coefficients were more than 0.9994. the relative standard, deviateon for 8 determinations of 100 u g/L of As3+ was 3.12% and the limit of detection, corresponding to a signal to noise ratio of three, was 18.4u g/L. The recovery ratio is more than 90%. The proposed method was applied to the determination of As3+ in water samples with satisfactory results, but for aquatic organism samples, the method should be improved.