| The situation of global environmental pollution is becoming more and more serious,and the damage of terrigenous Pollution to marine ecological environment is very serious.The establishment of the monitoring system of terrigenous pollutants in Qinhuangdao is to continuously,automatically and rapidly monitor the seasonal characteristics,regional distribution and total amount of terrigenous pollutants.Before the establishment of the monitoring system,this research mainly put forward reasonable suggestions on the monitoring time focus,regional focus and index focus of the monitoring system through the analysis and summary of sampling survey data;in the initial stage of the monitoring system,the environmental conditions,operation parameters and application scope of key equipment and facilities were optimized through simulation tests;and in the monitoring system trial run.In order to ensure the accuracy of the monitoring data,the water quality was studied to estimate the pollutant flux into the sea through the analysis of the monitoring data.In the early stage of this study,the data collected during the one-year survey were analyzed and studied,and some seasonal and regional characteristics were found.In season,the pollutant value is lower in flood season and higher in dry season.The heavy metal pollutants such as lead,hexavalent chromium and other heavy metal pollutants caused by the sudden increase of precipitation just entering flood season are tens of times higher than the standard of '?' types of water bodies.Later,the pollutant value gradually decreases with the steady flow of rivers.Total nitrogen and total phosphorus in Shihe,Xinhe and artificial rivers are higher than those in other five rivers.Based on the results of the investigation,the key monitoring suggestions are put forward in the areas of total nitrogen,total lead,seasonal change,abnormal weather,Shihe and Daihe.After the preliminary establishment of the monitoring system,the environmental conditions such as temperature,humidity,negative high voltage,lamp current,spectral band,etc.required by the workstation equipment,as well as the applicability of the testing equipment to the specific detection parameters were studied by using the workstation testing equipment to directly sample and detect the preset samples.In terms of testing environmental conditions,after comprehensive study on the requirements of sample collection equipment,pretreatment equipment facilities and operation environmental conditions of each testing equipment,it can be determined that all equipment and facilities can operate normally under the conditions of temperature 20?±5?,relative humidity50%±20%.In terms of testing equipment operation parameters,taking the total nitrogen/nitrate nitrogen monitor as an example,the best wave for total nitrogen/nitrate nitrogen detection can be obtained.With 221.5 nm in length,275.5 nm in background wavelength,1.0 nm in spectral bandwidth and 0.05 s in response time,the precision and accuracy of the measured data are the best.In terms of the applicability of the detection equipment for specific detection parameters,the optimum detection range is 0.1 mg/l~10 mg/l for nitrate,and the limit detection range is 0.05 mg/l~15 mg/l.During the trial operation of the monitoring system,the application of the key monitoring parameters of heavy metals such as lead,copper,zinc,hexavalent chromium,total nitrogen,nitrate,ammonia nitrogen,total phosphorus,phosphate,toxic and harmful substances such as fluoride ion,nitrite,TOC,COD and other organic compounds were sampled and compared.Through comparative study,it can be determined that the overall qualified rate of the five monitoring parameters of dissolved oxygen,sulfide,flow rate,nitrite nitrogen and fluoride ion is over 85%.The overall qualified rate of water temperature,pH,salinity,turbidity,COD,TOC,total nitrogen,nitrate nitrogen,total phosphorus,ammonia nitrogen and phosphate is over 90%.The overall qualified rate of total lead,copper ion,zinc ion,hexavalent chromium and divalent iron is over 90%.The overall qualified rate of accuracy is low,and there are some systematic errors.A correction coefficient can be obtained by statistical calculation of trial operation data for nearly one year.For example,the correction coefficients of eight workstations with total lead are 1.48,1.46,1.69,1.81,1.41,1.44,1.57 and 1.33,respectively.The overall qualified rate of accuracy of heavy metal parameters after correction factor is more than 95%.After the monitoring system was put into use,the monitoring data were analyzed and studied,and the quality of monitoring target water quality was evaluated through data analysis.Except Xinhe and Xinkai rivers,whose water quality reached the standard of three types of water in a few months,other rivers were in five categories and inferior five categories for most of the time,which resulted in the lower water quality evaluation mainly due to the total factor.Environmental protection and marine ecological departments should pay attention to the high pollution degree of eutrophic salts such as phosphorus and total nitrogen,which are easy to cause damage to the marine ecological environment and produce marine ecological disasters such as red tide.At the same time,the terrigenous pollutant flux of rivers in Qinhuangdao area was estimated by monitoring data.From March to December 2018,the pollutant flux into the sea was more than 7,000 tons.The New River has more than 2,000 tons of tidal flux,and the Dapu River has at least 200 tons.In terms of time,the three months of August,September and October have a larger flux,accounting for 40% of the President's measurement,while the rest months are relatively small.This study has played an active role in the continuous improvement of the monitoring system,the optimization of the operating conditions of equipment and facilities,the accuracy of the monitoring system results and the application of the monitoring system,and ensured the continuous and effective operation of the Qinhuangdao terrigenous pollutant monitoring system. |
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