Evaluation of PCB Concentrations, Masses, and Movement from Dredged Areas in San Francisco Bay

San Francisco Estuary Institute (SFEI) | March 28th, 2019

This report is a product of a Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) project funded to analyze sediment PCB data in the Dredged Materia

This report is a product of a Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) project funded to analyze sediment PCB data in the Dredged Materials Management Office (DMMO) database to address priority management questions for PCBs. 

Examination of the ocean as a source for atmospheric microplastics

PLOS | May 12th, 2020

Global plastic litter pollution has been increasing alongside demand since plastic products gained commercial popularity in the 1930s. Current plastic pollutant research

Global plastic litter pollution has been increasing alongside demand since plastic products gained commercial popularity in the 1930s. Current plastic pollutant research has generally assumed that once plastics enter the ocean they are there to stay, retained permanently within the ocean currents, biota or sediment until eventual deposition on the sea floor or become washed up onto the beach. In contrast to this, we suggest it appears that some plastic particles could be leaving the sea and entering the atmosphere along with sea salt, bacteria, viruses and algae. This occurs via the process of bubble burst ejection and wave action, for example from strong wind or sea state turbulence. In this manuscript we review evidence from the existing literature which is relevant to this theory and follow this with a pilot study which analyses microplastics (MP) in sea spray. Here we show first evidence of MP particles, analysed by μRaman, in marine boundary layer air samples on the French Atlantic coast during both onshore (average of 2.9MP/m3) and offshore (average of 9.6MP/ m3) winds. Notably, during sampling, the convergence of sea breeze meant our samples were dominated by sea spray, increasing our capacity to sample MPs if they were released from the sea. Our results indicate a potential for MPs to be released from the marine environment into the atmosphere by sea-spray giving a globally extrapolated figure of 136,000 ton/yr blowing on shore.

Expert review of the sediment screening guidelines for the beneficial reuse of dredged material in San Francisco Bay, Workshop Summary Report

Publisher not available | March 17th, 2020

Exploring scientific and management implications of upper trophic level food webs in the Delta

Delta Stewardship Council (Delta Council) | April 17th, 2024

The Sacramento-San Joaquin Delta (the Delta) has complex and evolving ecosystems characterized by multiple food webs that vary in time and space. Here, food webs are defi

The Sacramento-San Joaquin Delta (the Delta) has complex and evolving ecosystems characterized by multiple food webs that vary in time and space. Here, food webs are defined as the network of species interactions (competition, predation) and interactions with their environment that are related through the flow of energy through the ecosystem (e.g., Paine 1980). Physical modifications, in addition to the introduction of non-native species and the changing climate, have significantly altered the structure and energetic pathways of the food webs for decades. The science clearly suggests that predicting the impacts of habitat restoration, fisheries, changes in environmental drivers (e.g., climate, changes in nutrient loading, invasive species) on the ecological carrying capacity and productivity of the Delta, as well as the bioaccumulation of contaminants on species or the ecosystem, requires an understanding of food web processes.

Factors Affecting Marsh Vegetation at the Liberty Island Conservation Bank in the Cache Slough Region of the Sacramento–San Joaquin Delta, California

U.S. Geological Survey (USGS) | July 5th, 2017

The Liberty Island Conservation Bank (LICB) is a tidal freshwater marsh restored for the purpose of mitigating adverse effects on sensitive fish populations elsewhere in

The Liberty Island Conservation Bank (LICB) is a tidal freshwater marsh restored for the purpose of mitigating adverse effects on sensitive fish populations elsewhere in the region. The LICB was completed in 2012 and is in the northern Cache Slough region of the Sacramento–San Joaquin Delta. The wetland vegetation at the LICB is stunted and yellow-green in color (chlorotic) compared to nearby wetlands. A study was done to investigate three potential causes of the stunted and chlorotic vegetation: (1) improper grading of the marsh plain, (2) pesticide contamination from agricultural and urban inputs upstream from the site, (3) nitrogen-deficient soil, or some combination of these. Water samples were collected from channels at five sites, and soil samples were collected from four wetlands, including the LICB, during the summer of 2015. Real-time kinematic global positioning system (RTK-GPS) elevation surveys were completed at the LICB and north Little Holland Tract, a closely situated natural marsh that has similar hydrodynamics as the LICB, but contains healthy marsh vegetation. The results showed no significant differences in carbon or nitrogen content in the surface soils or in pesticides in water among the sites. The elevation survey indicated that the mean elevation of the LICB was about 26 centimeters higher than that of the north Little Holland Tract marsh. Because marsh plain elevation largely determines the hydroperiod of a marsh, these results indicated that the LICB has a hydroperiod that differs from that of neighboring north Little Holland Tract marsh. This difference in hydroperiod contributed to the lower stature and decreased vigor of wetland vegetation at the LICB. Although the LICB cannot be regraded without great expense, it could be possible to reduce the sharp angle of the marsh edge to facilitate deeper and more frequent tidal flooding along the marsh periphery. Establishing optimal elevations for restored wetlands is necessary for obtaining the full suite of ecosystem services provided by tidal wetlands. A better system of tidal benchmarks throughout the delta is needed to help restoration practitioners correctly grade the elevation of newly restored wetlands.

Final Environmental Impact Report for Adoption of a Regulation for the Hexavalent Chromium Maximum Contaminant Level

California State Water Resources Control Board (SWRCB) | April 17th, 2024

As the lead agency in accordance with sections 15089 and 15132 of the California Environmental Quality Act (CEQA) Guidelines (Cal. Code Regs., tit. 14, § 15000 et seq.),

As the lead agency in accordance with sections 15089 and 15132 of the California Environmental Quality Act (CEQA) Guidelines (Cal. Code Regs., tit. 14, § 15000 et seq.), this document is the Final Environmental Impact Report (Final EIR) for the adoption of statewide regulations setting the maximum contaminant level (MCL) for hexavalent chromium (Proposed Regulations). The Proposed Regulations include a maximum contaminant level (MCL) of 10 μg/L for hexavalent chromium. (Cal. Code Regs. tit. 22, § 64431 Table 64431-A.) The Proposed Regulations also include a compliance schedule based on public water system size, by adding subdivision (p) and Table 64432-B to section 64432 of title 22 of the California Code of Regulations, identifies a detection limit for purposes of reporting, sets monitoring and reporting requirements and public notice requirements for violations of the MCL, and establishes the Best Available Technologies (BAT) for treating hexavalent chromium in drinking water. California State Water Resources Control Board (SWRCB) Chrom VI MCL rulemaking chronology.

Final Report on the recovery of the Upper Sacramento River - subsequent to the 1991 Cantara spill

Cantara Trustee Council | June 18th, 2007

The Cantara Trustee Council (CTC), and the Cantara Program, operated for a period of 12 years, from 1995-2007. During that time, the CTC funded numerous projects which in

The Cantara Trustee Council (CTC), and the Cantara Program, operated for a period of 12 years, from 1995-2007. During that time, the CTC funded numerous projects which included restoration activities, land acquisition and protection, research, and public education. The purpose of this document is to leave a summary record of events that occurred due to the 1991 Cantara spill. It is our intent to provide a condensed presentation of the spill event, the legal processes following the spill, including the formation of the CTC, the formation of the Cantara Program, and the development of guiding plans and documents used by the CTC in the disbursement of settlement funds.

First flush analysis of urban storm runoff

Science of the Total Environment (Elsevier) | July 3rd, 2003

Stormwater runoff was monitored on 13 separate urban watersheds, which were chosen to represent distinct types of residential and industrial development, along with vario

Stormwater runoff was monitored on 13 separate urban watersheds, which were chosen to represent distinct types of residential and industrial development, along with various watershed characteristics. A total of 38 storm events were monitored to investigate the first flush phenomenon. The first flush phenomenon may be defined as the initial period of stormwater runoff during which the concentration of pollutants is substantially higher than during later stages. The magnitude of the first flush phenomenon, and if it actually occurs, was calculated using a method of data analysis which results in determining the ‘event mean concentration’ (EMC). The magnitude of the first flush phenomenon was found to be greater for some pollutants (e.g. suspended solids from residential areas) and less for others (e.g. chemical oxygen demand from industrial areas). No correlation was observed between the first flush phenomenon and the antecedent dry weather period, however, the first flush phenomenon was greater for smaller watershed areas.

Flame retardants and plastic additives in San Francisco Bay: Targeted monitoring of organophosphate esters and bisphenols

San Francisco Estuary Institute (SFEI) | January 31st, 2020

Fourth National Climate Assessment Chapter 3: Water

U.S. Global Change Research Program | November 23rd, 2018

Significant changes in water quantity and quality are evident across the country. These changes, which are expected to persist, present an ongoing risk to coupled human

Significant changes in water quantity and quality are evident across the country. These changes, which are expected to persist, present an ongoing risk to coupled human and natural systems and related ecosystem services. Variable precipitation and rising temperature are intensifying droughts, increasing heavy downpours, and reducing snowpack. Reduced snow-to-rain ratios are leading to significant differences between the timing of water supply and demand. Groundwater depletion is exacerbating drought risk. Surface water quality is declining as water temperature increases and more frequent high-intensity rainfall events mobilize pollutants such as sediments and nutrients. Click here for the text of the full report.