Isotope-based analysis method for nitrogen pollutants in offshore aquaculture water area

Abstract

The invention relates to an isotope-based analysis method for nitrogen pollutants in an offshore aquaculture water area. The contribution rate of aquaculture wastewater to nitrogen in offshore water is acquired in the manner of analyzing the abundance values of nitrogen isotopes in the offshore water and the aquaculture wastewater according to the different components of the nitrogen isotopes in different pollution sources and receiving water. The method specifically comprises the following steps: step 1, collecting samples on all the sampling sites before the flood tide according to nationalrelevant industrial standards; and step 2, adopting an isotope mass spectrometer for analyzing the abundance values of nitrogen, hydrogen and oxygen isotopes in all the samples, comparing with the abundance values of the isotopes of a standard sample, calculating an isotope rate value of the samples, accordingly calculating the abundance values of 2H-H20, 18O-H2O and 15N-NO3 in an effluent sample,an aquaculture wastewater sample and a tidal creek sample, and applying a bayesian network model for calculating the contribution rate of the pollution sources. Due to the use of the isotopes in theinvention, the accuracy of analysis result is increased, the monitoring workload is effectively reduced and the human and material resources are saved.

Description

technical field [0001] The patent of the invention belongs to the technical field of environmental pollution prevention and control, and specifically relates to an isotope-based analysis method for nitrogen pollutants in nearshore aquaculture waters. Background technique [0002] With the rapid growth of the population, the demand for seafood also increases, which in turn promotes the development of the mariculture industry. In order to increase the aquaculture output and shorten the aquaculture cycle, a large amount of bait and fertilizers in the aquaculture pond are rich in nitrogen pollution. The feces and unused bait produced after being used by aquaculture organisms enter the surrounding water body along with the aquaculture drainage, and accumulate in the surrounding water body, increasing the risk of eutrophication in the water body; therefore, while ensuring the aquaculture output, how to Monitoring, evaluating and controlling the pollutants produced by aquaculture i...

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Problems solved by technology

[0003] At present, there are few studies on the analysis of nitrogen pollutants in nearshore aquaculture drainage. The conventional methods are mainly large-scale sea area monitoring and indoor simulation analysis of aquaculture ponds. Due to the migration and transformation properties of nitrogen pollutants and the differences in the operation of different aquaculture ponds , so there are certain limitations in the application of these methods: large-scale sea area monitoring monitors the concentration of nitrogen pollutants through aerial survey sampling, which is affected by the draft and water depth of the ship, and the aerial survey route is far away from the coastal breeding area, usually at 4 ~5km away, and nitrogen is not stable in the water body, chemical transformation process will occur, the nitrogen pollution concentration monitored by the aerial survey sampling point is not the real nitrogen pollution concentration in the aquaculture drainage, so there are certain errors in the aerial survey sampling analysis; The indoor simulation analysis method is to analyze the distribution law of the concentration of nitrogen pollutants in the aquaculture drainage by artificially setting the aquaculture conditions, the amount of bait input, and the time interval of the aquaculture drainage. The shore farming areas are all semi-intensive and retail farming, and the farming conditions are complex and diverse, and the amount of bait fed is also quite different. Therefore, the indoor simulation analysis method cannot truly reflect the nitrogen pollutants released by the farming drainage; stable Isotopes will not decay in the environment, the composition is stable, and different pollution sources have different isotopic characteristics. Although the concentration of nitrogen pollutants in wastewater from different aquaculture ponds varies, the abundance of nitrogen isotopes in aquaculture wastewater is relatively fixed, which makes Isotopes have unique advantages in the analysis of nitrogen pollutants in aquaculture drainage

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