Comprehensive risk assessment and source identification of selected heavy metals (Cu, Cd, Pb, Zn, Hg, As) in tidal saltmarsh sediments of Shuangtai Estuary, China.

Heavy metals do not degrade and can remain in the environment for a long time. In this study, we analyzed the effects of Cu, Cd, Pb, Zn, Hg, and As, on environmental quality, pollutant enrichment, ecological hazard, and source identification of elements in sediments using data collected from samples taken from Shuangtai tidal wetland. The comprehensive pollution indices were used to assess environmental quality; fuzzy similarity analysis and geoaccumulation index were used to analyze pollution accumulation; correlation matrix, principal component analysis, and clustering analysis were used to analyze pollution source; environmental risk index and ecological risk index were used to assess ecological risk. The results showed that the environmental quality was either clean or almost clean. Pollutant enrichment analysis showed that the four sub-regions had similar pollution-causing metals to the background values of the soil element of the Liao River Plain, which were ranked according to their similarity. Source identification showed that all the elements were correlated. Ecological hazard analysis showed that the environmental risk index in the study area was less than zero, posing a low ecological risk. Ecological risk of the six elements was as follows: As > Cd > Hg > Cu > Pb > Zn.

[Research on Remote Sensing Inversion of Suaeda Salsa's Biomass Based on TSAVI for OLI Band Simulation].

Suaeda salsa(S.salsa) is a typical vegetation of coastal wetland in the north of Liaodong Bay. The S. salsa biomass assessment plays an important role in understanding the ecosystem productivity of coastal wetland and the formation of ecosystem structure and function. Usually the S.salsa coverage is inhomogeneous. The low S.salsa coverage can be found at a natural condition, the soil background has a strong influence on S.salsa spectral data. The Transformed Soil Adjusted Vegetation Index (TSAVI) used as independent variable was derived by the Landsat 8 OLI simulation data. The S.salsa biomass inversion models were built based on the regression analysis of TSAVI and ground measured biomass in this study. The correlation between TSAVI (600~687, 820~880 nm) and biomass was significant, the correlation coefficient was about 0.9, up to 0.92. The results of linear and quadratic models were better than those of logarithmic, exponential and power models, the determination coefficient r2 of linear and quadratic models were 0.83. Combined with F value and operation efficiency, the linear model was the best option for mature S.salsa biomass inversion. The linear model was applied to invert the S.salsa biomass by using the Landsat 8 OLI data in the study area and it was further validated using in-situ data. The correlation coefficient between the in-situ value and retrieved value was 0.962, the relative error was 0.106. For higher S.salsa coverage, the relative error was lower. The relative error of the low-cover S.salsa biomass inversion was around 0.18. The results showed that the established model has good accuracy for different coverage. In addition, with the introduction of ±5% error of soil line parameters a and b, the average relative errors were relatively stable, and the correlation coefficients were reduced, but all the correlative coefficients were above 0.9. The results showed that the established model is stable.

[Study on chemical constituents of Kochia scoparia].

OBJECTIVE: To investigate the chemical constituents of Kochia scoparia. METHODS: The constituents of EtOAc-soluble portion were isolated and purified by silica gel column chromatography. Their structures were identified by spectral features. RESULTS: Twelve compounds were isolated and identified as tectorigenin (1), pratensein (2), 5,2'-dihydroxy-6,7-methylenedioxyisoflavone (3), iriflogenin (4), 5-hydroxy-6, 7-methylenedioxyflavone (5), fumalicacid (6), N-trans-feruloylmethoxytyramine (7), N-transferuloyltyramine (8), stigmasterol (9), oleanolic acid (10), beta-stigmasterol (11), daucosterol (12). CONCLUSION: compounds 1-9 are isolated from this plant for the first time.