Long term trends in sewage abatement and water quality in the Hudson-Raritan Estuary
- New York City Dept. of Environmental Protection, NY (United States)
Long-term trends in dissolved oxygen (DO) and coliform bacteria concentrations are used to evaluate the impact of 70 years of sewage abatement and treatment in the Hudson-Raritan Estuary near New York City (NYC). Regional construction of wastewater treatment plants since the 1920`s has reduced discharges of untreated sewage into the estuary from approximately 47 M{sup 3}/S in 1936 to less than 0.1 M{sup 3}/S by 1994. From at least 1922 through the early 1960s, average summer DO percent saturation in the Hudson River varied between 35--50% in surface waters and 25--40% in bottom waters. Beginning in the late 1970s, DO concentrations increased through the 1980s and especially into the 1990s, coinciding with the secondary treatment upgrade of the 7.4 M3/s North River plant in the spring of 1991. Average summer percent saturation in the early 1 990s exceeded 80% in surface waters and 60% in bottom waters. In addition, summer DO minima increased from less than 1.5 mg/L in the early 1970s, to greater than 3.0 mg/L in the 1990s, and the duration of hypoxia during summer months has been reduced. While this general trend has been observed throughout the estuary, some areas have displayed recent declines in DO, possibly due to increasing eutrophication. Total coliforms also display strong decreasing trends from the 1960s into the 1990s, with declines attributed to plant construction and expansion, and improved operation of the sewer system. Metal loadings have also decreased significantly. Signs of improved ecosystem quality include reopened beaches and shellfish beds, re-infestation of woodpilings by marine wood-borers, and the resurgence of wading birds in several areas of the estuary.
- OSTI ID:
- 203590
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9614%%102
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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