曹妃甸海域化学需氧量(COD)的季节性分布特征

通过建立曹妃甸海域潮流、污染物输运数学模型，分析了洪枯季曹妃甸海域化学需氧量（COD）的变化规律。结果表明:季节性入海通量决定COD浓度空间分布，海域潮流运动控制COD动态迁移过程。曹妃甸甸头东部海域二泄大庄河口洪枯季均为COD高浓度区，最大浓度可达2.2 mg/L，大清河及二滦河COD浓度枯季明显降低，污染物涨潮向SW运移并向外海扩展，落潮沿NE向河口输运。甸头西侧海域COD浓度分布季节性变化不大，COD浓度主要集中于沙河口以及三友化工排污口附近海域，在NW-SE潮流作用下，COD呈涨潮向河口输运，落潮流向外海扩散的运动规律。

Seasonal and spatial distribution of chemical oxygen demand (COD) in Caofeidian sea area

Based on hydrodynamic and pollutant transport model, the transport processes of chemical oxygen demand (COD) in Caofeidian sea area under in flood and dry seasons are simulated.Numerical results show that COD concentration is determined by seasonal discharges and pollutants, while regional tidal current controls its dynamic transport process.In eastern Caofeidian sea area, the area of high concentration of COD exists in Erxiedazhuang estuary in both flood and dry seasons with maximum concentration of 2.2 mg/L, while concentration of COD in Daqinghe estuary and Erluanhe estuary decreases significantly in dry season.Pollutants expand to the sea along SW direction during flood tide and transport to the estuary again during NE ebb tide.In contrast, the seasonal variation of COD concentration distribution in western Caofeidian sea area is not significant, and COD mainly concentrated in Shahe estuary and drain outlet of Sanyou Chemical Industries Company.Effected by NW-SE direction reciprocating tidal current, COD transports toward estuary during flood tide while expand to the sea during ebb tide.