Heavy metal elements of Cu, Pb, Zn, Cd, Cr, Hg and As in the sediments of Weizhou Island in 2015—2016 were determined and assessed by using single factor pollution index, integrated pollution index and correlation coefficient. In 2015, the mass concentration of heavy metals showed that Hg<Cr<Cd<As<Pb<Cu<Zn, corresponding with 0.052 0, 0.2, 0.28, 0.521, 0.76, 1.0, 10.0 μg·L-1. In 2016, the relation was Hg<Cd<As<Cr<Cu<Pb<Zn with 0.019 4, 0.07, 0.406, 0.5, 1.3, 2.29, 45.8 μg·L-1, respectively. When referring the first class of seawater quality standard of China, the synthetical pollution indexes for 2015 and 2016 in Weizhou Island were both less than 1.0, which means the seawater of Weizhou Island in these two years was in clean status. However, the synthetical pollution indexes from the location of S4 and S6 at 2016 exceeded 1.0, demonstrating light and medium pollution in these sites. In addition, Mass concentrations of Pb, Zn and Hg were beyond the seawater quality standard of China and the excesses reached as high as 5.6, 11.7 and 0.3 times of the standard value, respectively. The heavy metal elements of Cu and Cd in 2015 and Zn and Hg in 2016 on Weizhou Island were positively correlated, with the correlation coefficients of 0.757 8 and 0.796 7, respectively. Heavy metal elements of Zn and Hg exceeding the standard limits were due to the anthropogenic activity in Weizhou Island. Heavy metal of As was in a general lower in Weizhou Island than in other Beibu Gulf seawaters, in contrast, heavy metal concentrations of Cu, Pb, Zn, Cd, Cr and Hg in seawater in this island were lower than those seawaters from tidal flat of Beibu Gulf, Beihai, Lianzhou Bay, Qinzhou Bay and Fangcheng. The latter areas are strongly influenced by industry, river input, agriculture and domestic pollution associated with human activity. In general, the level of heavy metal pollution of seawater in Weizhou Island is still clean, but there are individual stations beyond the standard.

To control seafood quality and regulate oyster aquaculture in Qinzhou Harbor, Beibu Gulf, the oysters (Crassostrea rivularis) were collected from three stations in the region in 2015, and analyzed by atomic fluorescence spectrophotometer and atomic absorption spectrometer. Overall, the content of heavy metals in Crassostrea rivularis exhibited Zn>Cu>Cd>Cr>As>Pb>Hg, and contents of Zn and Cu had the average of 532.03 and 126.96 mg/kg, respectively. Referring to aquatic products standard of NY 5073-2006, we found, with the exception ofCrassostrea rivularis collected at the 2nd station of July, the level of Cu from 89% samples exceeded the limit. While referring to aquatic products standard of GB 2762-2012, only the level of samples from the 3rd station of July went beyond the limit. Contents of Pb and Hg were low, with an average of 0.02 and 0.009 mg/kg, respectively. The dietary intakes of heavy metals in Qinzhou Harbor's Crassostrea rivularis were lower than the recommended values of Joint FAO Expert Committee on Food Additives (JECFA), thus the oysters in this region are safe for edibility.

2014年9-11月对广西北部湾市售双壳经济贝类进行采样,采用高效液相色谱法(HPLC)分析麻痹性贝毒(PSP)毒素含量及毒素组成,评价其食用安全性.结果显示采集于北海、东兴、防城港、涠洲岛4个市场的16种市售贝类中均检出麻痹性贝毒,毒素含量为0.24-290.10 μg STXeq· 100 g-1,检出率100％.毒素成分包括GTX类、STX类和C类.其中,dcGTX2、C2、GTX4三者检出率最高,分别为73％、52％、42％.涠洲岛采集的波纹巴非蛤与防城港采集的紫贻贝PSP含量高于联合国规定的麻痹性毒素警戒标准,分别是警戒标准的3.6倍和1.02倍,样品总超标率达6.06％.贝类消化腺和贝肉均检出PSP,前者明显高于后者,建议食用贝类时,去除腺体以降低麻痹性贝类毒素中毒的风险.总的来说,广西北部湾PSP染毒情况不容乐观,亟需加强监控.