Long-term (summer 2015–2018 and short-term (summer 2018) water quality monitoring was performed to understand spatial and temporal variations of surface water quality in the Newark Bay Estuary, as well as the Upper New York Bay, parts of the Hudson-Raritan Estuary in the New York–New Jersey metropolitan area. Electrical conductivity (EC), pH, temperature, and dissolved oxygen (DO) were measured in the field, while dissolved nitrate, phosphate, and ammonia concentrations were determined in the laboratory. Long-term and short-term water quality monitoring data consistently indicated that nutrients are significantly elevated in the Hackensack River most likely due to sewage effluent from a major sewage treatment plant. Dissolved oxygen levels were sufficiently high in most parts of the estuaries, whereas the Hackensack River showed a sign of hypoxia. Nutrients in the estuaries showed significant temporal variations typically by 2 to 3-fold during the 1-month short-term monitoring period, and were correlated with EC, DO or pH. The effects of combined sewer overflows (CSOs) during wet weather on the water quality of Newark Bay appeared uncertain except for ammonia, but long-term effects of CSOs need to be further investigated because nutrients from CSOs can accumulate in bottom sediments and be remobilized. Frequent water quality monitoring is necessary to better understand the impact of human activities on temporal variations of nutrients in urban estuaries and to efficiently protect coastal ecosystems.

在1个月的短期监测期间，河口中的营养物质显示出明显的时间变化，通常变化2至3倍，并与EC，DO或pH相关。潮湿天气下的下水道溢流（CSOs）对纽瓦克湾水质的影响似乎不确定，除了氨气外，但由于来自CSOs的养分会积聚在底部沉积物中并被迁移，因此需要进一步研究CSOs的长期影响。为了更好地了解人类活动对城市河口养分的时空变化的影响并有效保护沿海生态系统，必须进行频繁的水质监测。潮湿天气下的下水道溢流（CSOs）对纽瓦克湾水质的影响似乎不确定，除了氨气外，但由于来自CSOs的养分会积聚在底部沉积物中并被迁移，因此需要进一步研究CSOs的长期影响。为了更好地了解人类活动对城市河口养分的时空变化的影响并有效保护沿海生态系统，必须进行频繁的水质监测。潮湿天气下的下水道溢流（CSOs）对纽瓦克湾水质的影响似乎不确定，除了氨气外，但由于来自CSOs的养分会积聚在底部沉积物中并被迁移，因此需要进一步研究CSOs的长期影响。为了更好地了解人类活动对城市河口养分的时空变化的影响并有效保护沿海生态系统，必须进行频繁的水质监测。