渤海湾天津近岸海域沉积物氮赋存形态及其环境意义

本研究采用连续分相浸取法，研究了渤海湾近岸海域沉积物中离子交换态氮（IEF-N）、碳酸盐结合态氮（CF-N）、铁锰氧化态氮（IMOF-N）及有机态和硫化物结合态氮（OSF-N）4种可转化态氮（TF-N）的含量及空间分布特征，进而揭示其环境意义。结果表明，表层沉积物中TF-N含量范围为145~233μg/g，均值为193...

Nitrogen forms and their environmental significance in the sediments of Tianjin coastal waters,Bohai bay

The concentrations and spatial distribution characteristics of the transferable nitrogen (TF-N) including ion-exchangeable form (IEF-N), carbonate form (CF-N), iron-manganese oxides form (IMOF-N) and organic matter-sulfide form (OSF-N) in the sediments of the coastal waters of Bohai bay were studied by the sequential extraction method, and further to reveal their environmental significance. The results showed that the concentrations of TF-N in the surface sediments ranged from 145 μg/g to 233 μg/g, with an average value of 193 μg/g. Affected by terrestrial sources, the overall distribution characteristics of nearshore content were higher than far shore; the proportion of nitrogen forms in TN was: IEF-N (9.6%) > IMOF-N (4.4%) > OSF-N (3.9%) > CF-N (0.08%), and their spatial distribution was different. The vertical variation range of TF-N concentrations was 24 ~ 313 μg/g, and the vertical distribution varied in different research sites. IEF-N and IMOF-N in TF-N showed an increasing trend with increasing deposition depth, OSF-N had different vertical distributions at different stations, the concentrations of CF-N was the smallest, and its vertical change was not significant. According to the sediment quality assessment guidelines, TN in the sediments in the study area was at the lowest level; The absolute contributions of various forms of nitrogen after being completely released according to binding capacity to the overlying water were as follows: IEF-N (44.4%) > OSF-N (35.4%) > IMOF-N (19.7%) > CF-N (0.5%).