摘要
研究和测定海水中汞的存在形态和在海水-底质间的相互交换,对于探明汞在海洋中的转移变化及其最后归宿,评价海区汞的自净能力,以及防治汞对海洋的污染等均具有重要意义。
In this paper, the concentrations of total Hg, inorganic Hg, methyl-mercury in sea water, and those adsorbed on particulate matter in water samples taken from fifteen coastal sites of Jiao Zhou Bay near Qingdao have been determined and reported. And a laboratory experiment of seawa-ter-sediment interchange of Hg has also been performed.Interesting results are obtained.1 、 As we have seen in Table 1 -3 , the percentage of KgInorg/ HgTo (a)in water samples at sites outside the Bay ( sites 101, 102、 103、 104 )and site 3A are 11-17%. It shows that the Hg in water samples taken from sites far from Hg sources is mainly existed in organic combined state or organo compds. The percentage of HgInorg/HgTo(a) in samples at sites 5、 6、 4A、 4B、 6A、 6B which naer the sources of inorg. Hg is significantly higher.2 , The concns. of inorganic Hg in seawater samples taken on July. 5th. 1978 are lower than those observed on Nov. 1 st. 1978 and Sep. 5th. 1977 in the same region.The possible explanation is that the concns. of suspended matter in samples collected on July, 5th, 1978 are much higher than those in the two other surveyings. This rule is in agreement to the concns. of inorg. Hg in coastal sea waters of England and East China Sea observed by Gardner(1975). 3、 The reaults from table 2 show that the concn. of methyl mercury in sea water sample at site 6 is 0.0012 ppb. It is equivalent to 1. 7% of the total Hg (0.069 ppb) in water sample. Our results indicate that the methyl mercury surely exists in sea water at the coastal site near Jig source,although the concn. of methyl Hg is exceedingly low in this water sample and plays an insignificant role in the transport of mercury to the ocean.4 、 The results of laboratory experiment of absorption show that the absorption percentage of Hg from sea water by the suspended marine sediment is 59.3% at a 1 ppb level of Hg in sea water and a water-sediment ratio of 1000:1 (Table 4). It is apparent that the suspended particulate matter acts as a 'scanvenger' of inorganic Hg in sea water.5、 The results of Table 2 and 3 show that with the exception of individual site, there is a positive correlation between the concns. of total particulate Hg and concns. of Hg which can be released by cone. HC1 and determined directly.According to the results of the surveyings and laboratory experiments (2 and4) , we consider that the unstable combined portion of total particulate Hg mostly is much more likely formed by adsorption of inorg. Hg onto suspended solids.6, The results of Table 5 indicate that the release of Hg into sea water from Hg polluted sediment is little (0. 11 ppb at most, Fig . 2)It seems to be possible that the release of Hg from Hg polluted sediment will not cause the 'secondary pollution' of sea water under ordinary conditions. However, the mercury contaminated sediment is still an important pollution source to the nektons and benthos.