Water Quality Monitoring and Trends in New York Harbor

Water pollution in the New York Harbor has been quantified each summer since 1909 for conventional and, more recently, nonconventional (i.e., toxic) parameters. Construction and upgrading of water pollution control plants have provided long-term improving trends for conventional water quality (DO, coliform bacteria, BOD, and nutrients), but not for heavy metal concentrations, except for lead at some sites. DO saturation is increasing, returning to 1909 conditions. Analysis of compliance with State water quality standards indicates increasingly acceptable DO and bacterial levels, but unacceptable concentrations of heavy metals. An industrial pretreatment program has been initiated to reduce toxics pollution. The data represent weekly samples at each of 52 stations each summer. Regression and factor analyses show relationships among variables and are helpful in determining the causes of the observed conditions. This paper highlights turning points in water quality over the last 80 years.