| In this paper, based on the survey data of Yangshan LNG project, select 17℃, 27℃, 22℃respectively represent spring, summer and fall. In accordance with the principles of scientific feasibility, set the residual chlorine concentration of 0mg / L (control group ), 0.02mg / L (A group), 0.08mg / L (B group), 0.14mg / L (C group), 0.20mg / L (D group), select the plankton model organism Chlorella vulgari and Artemia salina as subjects. A study was conducted on the effects of residual chlorine in the cold drainage on Chlorella vulgari and Artemia salina. In toxicological tests based on the combination in September 2009 and September 2010 two cruises of the marine environment of the survey results to assess the residual chlorine on marine plankton in the loss of resources.Specific research results are as follows.(1)The results of toxicity test for Chlorella vulgari showed that: under 17℃, the residual chlorine concentration of group A and B is lower.Chlorella vulgari growth and the control group similar. Chlorella vulgari growth similar to the control group did not show significant difference. Early in the trial group C did not show significant differences. After 72h, algal cells were lower fluid, residual chlorine was significantly increased its inhibitory. The highest concentration of chlorine group D, cell concentration continued to decline. Under the conditions of 17℃, 0.20mg / L for Chlorella vulgari showed significant inhibitory effects and inhibition increased with time. Under 22℃, growth status of each concentration group is basically the same. After 48h, A B C group of algal cell concentration than the control group solution. Residual chlorine is not obvious on the growth inhibitory effects. 72h, D group showed some inhibitory effect, algal cell concentration lower than the rest of the liquid test group. 27℃and 17℃in the initial test showed a similar law. Compared with the control group, low concentration no significant inhibitory effect of each group .The highest concentration of D group, Chlorella vulgari growth was inhibited. Late in the test, D group growth accelerated. Chlorella vulgari demonstrate the adaptability of residual chlorine.(2)The results of toxicity test for Artemia salina showed that: under 17℃, the 96h LC50 of Artemia salina stressed by residual chlorine is 0.186 mg/L.Test groups were not death occurred within 48h. 72h, in addition to the control group, there were deaths in other groups. Group B C lower mortality, group A and D is equal. In the 72h-96h time period, mortality of the group A is unchanged. Mortality of the other groups is increased. D group the largest increase, 96h mortality rate of 53.33% .With the exposure time increase, the more obvious lethal effects. With the increase of chlorine concentration, the mortality rate increased faster.Conditions at 22℃, the 96h LC50 of Artemia salina stressed by residual chlorine is 0.126 mg/L. Similar with 17℃, test groups were not death occurred within 48h.In the 72h-96h time period, mortality of the group A is unchanged. Mortality of the other groups increased. D group the largest increase, reaching 86.67%. Compared with 17℃, under 22℃With the exposure time increase, the more obvious lethal effects. In the same chlorine concentration, the same action time, 22℃mortality is higher. Conditions at 27℃, the 24h LC50 of Artemia salina stressed by residual chlorine is 0.12 mg/L. The lethal effect of residual chlorine on the Artemia salina is more obvious. The mortality of C group has risen to 40%. D has more than 50%. In the 8h-12h time period, CD group increased mortality rate is 3-4 times the AB group. In the 24h-48h time period, AB group increased mortality rate is 2-3 times the CD group.(3)In September 2009 and September 2010 near the LNG project area survey data of 16 stations show that groups of phytoplankton mainly euryhaline marine component. Fresh water component, true estuarine component and high salinity component have occurred, but fewer species. Main dominant species of phytoplankton is Skeletonema costatum and so on. In 2009, phytoplankton species of high tide is 39, 28 species at low tide. In 2010, phytoplankton species of high tide is 39, 29 species at low tide. Compared with September 2009, September 2010 abundance of phytoplankton in the vicinity is significant growth. September 2009 average cell abundance of high tide is 3.61×107 ind/m3, 3.82×107 ind/m3 at low tide. September 2010 average cell abundance of high tide is 177.5×107 ind/m3, 185.4×107 ind/m3 at low tide.The major species of Zooplankton near the engineering are estuary low salinity groups and true estuarine groups. Fresh water component have occurred, but fewer species. Main dominant species of zooplankton is Acartia pacifica and so on. In 2009, zooplankton species of high tide is 32, 29 species at low tide. In 2010, zooplankton species of high tide is 30, 30 species at low tide. Compared with September 2009, September 2010 abundance of phytoplankton in the vicinity is significant reduce. September 2009 average cell abundance of high tide is 181.17ind/m3, 112.84ind/m3 at low tide. September 2010 average cell abundance of high tide is 51ind/m3, 62.34 ind/m3at low tide.(4)It based on the basic formula?which?derived by XU Zhaoli et al. Combination of survey data near the Yangshan LNG project. Under the conditions of 27℃, 0.08 mg / L, toxicological mortality of the different observation time points, the theoretical maximum loss of phytoplankton was 17.93*1010ind, the theoretical maximum loss of zooplankton was 9.87*106indThrough September 2009 and September 2010 the actual investigation of the project area, the test to verify the theoretical value obtained. Found out that compared with 2009, the abundance of phytoplankton cells was increased, the zooplankton cells were reduced. |
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