Author(s): DAI Ming-xin1, 2, PENG Shi-tao1, 2, MAO Tian-yu2, BAI Zhi-peng11.College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China2.Laboratory of Environmental Protection in Water Transport Engineering, Tianjin Research Institute for Water Transport Engineering, Tianjin 300456, China
Pages: 8-12
Year: 2009 Issue:  4
Journal: Research of Environmental Sciences
Keyword:  Bohai Bay; dissolved inorganic nitrogen(DIN); spatial-temporal variation;
Abstract: We studied the characteristics of dissolved inorganic nitrogen(DIN) from 17 monitoring sites in Bohai Bay over the past 11 years.The statistical characteristics,seasonal differences and spatial-temporal variation of DIN in the research area were analyzed using box-plots,correlation analysis,Mann-Kendall and spline interpolation methods.The reasons causing DIN mass concentration variation at Bohai Bay were also analyzed.The results showed that the DIN mass concentrations were mostly positively skewed,and the DIN mass concentrations in the 2,4 and 6 monitoring sites were the highest of all the sites.This indicates that the DIN mass pollution from land-based sources and the port development should not be neglected.The DIN mass concentrations over high-flow period and mean-flow period were significantly correlated,although those over low-flow period were not.As for the temporal variation,during the 11 years,the DIN mass concentrations at Bohai Bay increased first,then remained steady for several years,and then increased rapidly.As for the spatial distribution,the mass concentration of DIN was higher in North Bohai Bay than in the South,and higher near-shore than off-shore.