深圳近岸海域全氟化合物的污染特征

Pollution Characteristics of Perfluorinated Compounds in Offshore Marine Area of Shenzhen

为探究深圳近岸海域全氟化合物(perfluorinated compounds,PFCs)的污染特征,2013年9月采集了深圳近岸(离岸﹥2km)10份表层海水和7份表层沉积物.采用固相萃取分离、富集,结合高效液相色谱-质谱联用的方法测定了其中16种PFCs的含量.结果表明,表层海水中有10种PFCs不同程度地检出,包括C4、C6和C8全氟磺酸盐(perfluorinated sulfonates,PFSAs)和C5~C11全氟羧酸(perfluorinated carboxylic acids,PFCAs).ΣPFCs质量浓度范围在1.74~14.7 ng·L-1之间,其中PFBS、PFOS和PFOA是主要的PFCs.ΣPFCs质量浓度分布呈西高东低的态势,伶仃洋和深圳湾ΣPFCs质量浓度显著高于大亚湾和大鹏湾(P<0.05),距岸越远ΣPFCs质量浓度越低.表层海水中PFCs可能主要来自于近岸污水的排放以及河流入海的输入.表层沉积物中有8种PFCs不同程度地检出,包括C6和C8PFSAs和C5,C6,C8~C11PFCAs.ΣPFCs含量范围在2.22~2.62μg·kg-1之间,其中PFOS是主要的PFCs.ΣPFCs含量变化很小,可能主要来自对上覆海水中PFCs的吸附.沉积物吸附PFCs的能力随碳链长度增加而增强,且相同碳链长度的情况下,PFSAs较PFCAs更易于被吸附.此外,不同近岸海域PFCs质量浓度比较结果表明,深圳近岸海域表层海水PFBS污染较为严重,而沉积物PFOS含量与其他海域相差不大.

In order to explore the pollution characteristics of perfluorinated compounds( PFCs),10 surface seawaters and 7 surface sediments were collected in offshore marine area of Shenzhen( offshore distance > 2km) in September 2013. All the samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography-tandem mass spectrometry( HPLC-MS /MS). The results showed that 10 PFCs,including C4,C6 and C8perfluorinated sulfonates( PFSAs) and C5-C11 perfluorinated carboxylic acids( PFCAs) were detected in the surface waters. Σ PFC concentrations ranged from 1. 74 ng·L- 1to 14. 7 ng·L- 1with PFBS,PFOS and PFOA being the dominant compounds. The spatial distribution of Σ PFC concentrations displayed the characteristic of 'the west being higher than the east',with Σ PFC concentrations of Lingding Sea and Shenzhen Bay being higher than those of Daya Bay and Dapeng Bay( P < 0. 05). The farther the sampling location was from the shore,the lower the Σ PFC concentrations were. Direct sewage emissions and rivers emptying into the sea might be the primary sources of PFCs in the surface seawaters. 8 PFCs,including C6 and C8PFSAs and C5,C6,and C8-C11 PFCAs were detected in the surface sediments. Σ PFC concentrations ranged from2. 22 μg·kg- 1to 2. 62 μg·kg- 1with PFOS being the dominant compounds. There was a small change of Σ PFC concentrations in surface sediments,which might be contributed by the adsorption from overlying water. The adsorption of PFCs on sediment significantly increased with the increasing length of carbon chain,and the adsorption of PFSA was higher than that of PFCA with the same length of carbon chain as PFSA. Additionally,the comparison with other seawater PFC measurements showed high PFBS pollution in this study,whereas the level of PFOS in sediment was close to those of other studies.