This year marks the 50th anniversary of a transformational
turning point for Bay water quality: passage of the Federal
Water Pollution Control Act Amendments of 1972, commonly
known as the Clean Water Act (CWA).
On the occasion of this momentous milestone, this edition of
The Pulse of the Bay includes nine
perspectives written by representatives of the groups
that have a prominent role in managing Bay water quality,
and profiles of the parameters that have been the main water quality
concerns over the past 50 years, with a focus on long-term
trends and a historical perspective.
The CWA provided a legal framework and a considerable amount of federal
funding (over $1 billion, equivalent to approximately $7
billion in 2022 dollars) that drove a rapid and remarkable
improvement in Bay water quality. By 1987, all municipal
wastewater treatment plants but one were providing
secondary treatment, which effectively removes oxygen demanding
organic matter and bacteria as well as many
toxic metals and organic chemicals. Bay monitoring data
available for the 1970s and 1980s show that dissolved oxygen
levels increased, and bacteria and toxic metal concentrations
sharply declined. By 1982, public harvesting of shellfish in
San Mateo County was approved for the first time in 50
years. By 1987, the Water Board concluded that swimming
was safe in most areas of the Bay during summer.
