PSR-FCCLP model based total maximum allocated loads optimization of TN and TP in Bohai Bay.

Eutrophication is a global problem for coastal ecosystems, one that Bohai Bay, China, has been severely afflicted due to rapid economic and social development in the past decades. It was urgent to manage the total maximum allocated loads (TMALs) of the total nitrogen (TN) and total phosphorus (TP) on land-based, which was closely related to coastal eutrophication. In this study, from the perspective of economy-resources-environment (ERE) system, we presented the fuzzy credibility constrained linear programming based on pressure-state-response (PSR-FCCLP) model, which calculated the TMALs of TN and TP at three credibility levels (λ = 0.55, 0.75, and 0.95) in Bohai Bay. The results showed that when the credibility level increased from 0.55 to 0.95, the TMALs of TN and TP would decrease from 13,573.38 t/a to 12,820.00 t/a and from 2665.58 t/a to 2514.90 t/a, respectively. This study will provide support for environmental management in coastal regions.

Regime shifts in trophic status and regional nutrient criteria for the Bohai Bay, China.

Identifying trophic status shift and developing nutrient criteria were considered important for controlling coastal eutrophication. Based on data from 1980 to 2018, we used sequential t-test analysis of regime shifts and assessment of coastal trophic status models to detect regime shifts in trophic status in Bohai Bay (China). We identified four distinct periods: unimpaired (1980-1984), minimally impacted (1985-1994), tipping point (1995-1999) and severely degraded (2000-2018). Using the reference conditions at different trophic status, a frequency distribution analysis was performed to develop candidate nutrient criteria. By considering other factors, such as the quantity and quality of data and long-term nutrient variations, we determined recommended criteria for dissolved inorganic nitrogen (15.3 µmol L-1) and phosphorus (0.42 µmol L-1) in Bohai Bay. This study provides a novel and feasible approach to determine reference conditions for the determination of nutrient criteria for coastal waters.

[Determination of arsenic species in bunge pricklyash seed by HG-AFS].

Some of traditional Chinese medicine (TCM) contain arsenide, such as realgar. The total amount of arsenic in the TCM exceeds the limits according to related regulations. But the roles of arsenic in TCM or its side-effects depend on its species existing in those therapies, not on the total amount of arsenic. Therefore, in recent years, the analysis of arsenic in TCM focuses on the species of arsenic. The present paper combines the method of extracting chemical composition from bunge pricklyash seed and analyzing the contents and the speciation of arsenic of bunge pricklyash seed (BPS) in different habitat by atomic fluorescence spectrometry (AFS-3100). By using 0.45 microm filter membrane and mixed solvent, two different species of the decoction of BPS were extracted, named the suspended and the soluble, and by using ion-exchange resin, the soluble arsenic could be separated as As(III), As(V), MMA and DMA. The authors established the segregation analysis methods for those species. The results shows that BPS in different habitat all contain arsenic, mostly as the species of inorganic arsenic, and the contents of As(V) are higher than As(III). The lixiviating rate of arsenic is highest with the solvent of methanol-water (4/1), reaching 53.7%-62.3%. The recovery of the method was 96.0%-101.3% and the relative standard deviation was less than 2.66%. The results show that the sensitivity and reproducibility of this method were excellent, and provided theoretical basis for further development of BPS

[Speciation analysis of zinc in bunge pricklyash seed by AAS].

A method was developed for the investigation of the contents and the speciation of zinc in bunge pricklyash seed (BPS) in different habitats by atomic absorption spectrum (AAS). By using 0.45 microm filter membrane and chloroform, four different species of the decoction of BPS, named the suspended, the soluble, the inorganic and organic species, were obtained, and the segregation analysis methods for those species were developed. The octanol-water system was proposed to simulate the distribution of decocted zinc in the stomach and the intestine of the human body. The results showed that the decocted zinc was the main content of the total zinc, and the contents of zinc were different in different habitats, but the percentages of decocted zinc and the organism zinc were similar. The recovery for the method was 97.5%-104.0% and the relative standard deviation was less than 2.36%. The results showed that the sensitivity and reproducibility of this method were excellent.