Behavior features of heavy metals in the Haikou Bay waters

Dissolved Cu, Ph, Zn and Cd in the Haikou Bay waters were measured to be respectively in the range concentrations of 0.47-1.16 μg/dm^3, 0. 94-- 2. 36μg/dm^3, 1.28-4.83 μg/dm^3 and 0. 005-0.072μg/dm^3; with respectively average values of 0.78μg/dm^3, 1.36μg/dm^3, 3.14 g/dm^3 and 0. 03 μg/dm^3. Dissolved Cu and Zn concentrations are relatively high at the stations near the Longkun Road Outfall for domestic sewage, the Xiuying Outfall for industry waste water and the Haidian Island Estuary, but dissolved Pb and Cd concentrations are low in these stations. The values in Other stations are comparatively homogenous. Vertical dissolved Cu, Pb and Zn concentrations at the bottom layer are higher than at the surface layer, but dissolved Cd concentration appears to be on the opposite. The measurement results of Cu, Pb, Zn and Cd in suspended particle show that particulate matters in the Haikou Bay seawater play a role in purifying heavy metals. The study on strong complexed form and non-liable form of dissolved copper show that the ratio of strong complexed form and dissolved form is about 85%, and non-liable form is very low with a value lower than 5 nmol/dm^3. Therefore, copper in the Haikou Bay seawater cannot cause influence on marine organisms.

A discussion on typhoon occurred in the Haikou Bay and impact mechanism on seawater quality

Water quality parameters such as pH, DO, COD, PQ4 - P, SiO3 - Si, NO2 - N, NO3 -N in the Haikou Bay were monitored respectively before and after Typhoon 9618 occurring on Sep. 18, 1996. Based on the statistics of typhoon in the Haikou Bay and numerical calculation of stormy current, the mechanism of water quality variation caused by typhoon is discussed. The typhoon impact on the Haikou Bay usually appears between July and November, most usually between August and October. The monitoring results before a typhoon were different from that. The stormy wave and windstorm cur-rent stir up the sediment in near-shore bottom and make the bottom water mix with the surface water strongly, specially windstorm current with strong velocity at the head of the bay stirs up higher pollutants sediment near sea area of sewage outfall, and heavy rain with typhoon carries the pollutants from land through the Nandu River to the Haikou Bay, so the contents of COD, PO4 - P, NO4 - N, NO3 ~N, SiO3 after a typhoon are higher than those before. Windstorm current is violent, which makes offshore high DO water exchange more frequently with inner bay water and oxygen in the air dissolves in sea water faster, so DO content after typhoon is higher than that before typhoon. This strong action of water exchange also causes lower pH change before and after the typhoon.

AstudyonseawaterapparentheavymetalcomplexationcapacityintheHaikouBay

Using semidifferential stripping technique combined with pre-equilibrium complexometric titration, theabnormal phenomena appeared in determining apparent complexation capacity ( ACC) are discussed and the improvedmethod for determinimg ACC is presented in the article. The accuracy of ACC measurement results is tested theoreti-cally and experimentally . Based on determination of ACC Cu, ACC Pb and ACC Cd, copper was selected for complexo-metric titration to determine ACC and the results are proved to be reasonable. ACC Cu measured in the Haikou Bay sur-face water is in the range of 166 . 4 ￣ 320 . 2 nmol/dm3, with the mean value of 240 . 9 nmol/dm3, the maximum valuearound domestic drainage outfall, and the values in other stations are comparatively homogenous. The condition forma-tion constant is in the range of 3 . 46 x 107 ￣ 4 . 76 x 108, and the mean value is 1 . 7 x 108 . Based on the 1 : 1 comlexingmodel of copper-natural organic ligand and the toxic concentration limit to marine organisms, seawater self-purificationcapacity in the Haikou Bay is calculated to be 7 . 43 ug/dm3 .