This year marks the 50th anniversary of a transformationalturning point for Bay water quality: passage of the FederalWater Pollution Control Act Amendments of 1972, commonlyknown as the Clean Water Act (CWA). On the occasion of this momentous milestone, this edition of The Pulse of the Bay includes nineperspectives written by representatives of the groupsthat have a prominent role in managing Bay water quality, and profiles of the parameters that have been the main water qualityconcerns over the past 50 years, with a focus on long-termtrends and a historical perspective. The CWA provided a legal framework and a considerable amount of federalfunding (over $1 billion, equivalent to approximately $7billion in 2022 dollars) that drove a rapid and remarkableimprovement in Bay water quality. By 1987, all municipalwastewater treatment plants but one were providingsecondary treatment, which effectively removes oxygen demandingorganic matter and bacteria as well as manytoxic metals and organic chemicals. Bay monitoring dataavailable for the 1970s and 1980s show that dissolved oxygenlevels increased, and bacteria and toxic metal concentrationssharply declined. By 1982, public harvesting of shellfish inSan Mateo County was approved for the first time in 50years. By 1987, the Water Board concluded that swimmingwas safe in most areas of the Bay during summer.
