| In order to reveale the inter-annual variation trends, this paper proceeds stations and total analysis with inorganic nitrogen (NO2-N、NO3-N、NH4-N) content and inorganic phosphorus (PO4-P) content in ecology-monitoring area of Changli in Hebei province on August each year from 2006 to 2010. And we combine with sea water quality standards for potential eutrophication assessment. The analysis results show that: inorganic nitrogen total content (DIN) had continued to decline for the first 4 years, but it has rapidly rose to a record high level in 2010. Among them, the overall level of NO3-N content is far higher than NO2-N content and NH4-N content,becomes a major component of DIN, and inorganic phosphorus content presents the volatility of the rising trend. The results of the potential eutrophication assessment show that: the nutrient levels of 19 stations are P limited potential eutrophication (ⅥP) in 2010, other years of the individual stations are N or P limited potential eutrophication (ⅤN or ⅥP) and moderate nutrition (Ⅱ), and others are poor nutrition (Ⅰ). This paper has important practical significance that we can improve marine water quality conditions and rational use of marine resources. |
