Methods of Analysis—Determination of Pesticides in Filtered Water and Suspended Sediment using Liquid Chromatography- and Gas Chromatography-Tandem Mass Spectrometry

U.S. Geological Survey (USGS) | January 31st, 2024

The widespread application of pesticides in agricultural and urban areas leads to their presence in surface waters. Presence of these biologically active chemicals in en

The widespread application of pesticides in agricultural and urban areas leads to their presence in surface waters. Presence of these biologically active chemicals in environmental waters potentially has adverse effects on nontarget organisms. To better understand the environmental fate of these contaminants, a robust method to capture chemicals with wide-ranging physicochemical properties has been developed. The method was developed by the U.S. Geological Survey’s Organic Chemistry Research Laboratory to monitor pesticides, pesticide degradates, and other agrochemicals in environmental surface waters throughout the country. The analysis involves a multiresidue method to determine 183 pesticides and pesticide degradates in filtered water samples and 178 pesticides and pesticide degradates in paired suspended sediment samples. After the filtration of whole water, contaminants are individually measured in the filtered water and the collected suspended sediment. Filtered water is extracted via solid-phase extraction, whereas suspended sediment is extracted using an ultrasonication, solid-liquid extraction. Samples are analyzed by liquid chromatography-tandem mass spectrometry using an electrospray ionization source in positive and negative modes and analyzed by gas chromatography-tandem mass spectrometry using an advanced electron ionization source in positive mode. Instrument parameters were optimized for the highest sensitivity, and at least two transitions (quantifier and qualifier) were monitored for each analyte. Recoveries in test filtered water (n=9; 183 analytes) from the American River, California, and suspended sediment (n=9; 178 analytes) samples fortified at 15 nanograms per liter (ng/L) ranged from 70.1 to 121.0 and 71.1 to 117.0 percent in water and suspended sediment filter samples, respectively.

Microbial Water Quality at Minimally Human-Impacted Reference Beaches in Northern California

San Francisco Estuary Institute (SFEI) | September 3rd, 2018

All of the coastal reference beaches that have been used by the State of California for quantifying “natural loads” of fecal indicator bacteria have been in Southern

All of the coastal reference beaches that have been used by the State of California for quantifying “natural loads” of fecal indicator bacteria have been in Southern California. None has been in the northern and central coastal regions of the State. To fill this information gap, this study assessed bacteria concentrations at coastal reference beaches in Northern California, investigated possible factors influencing the bacteria concentrations, and evaluated how these concentrations compare to results from the Southern California reference beaches. Reference beaches were defined as open beaches with breaking waves that receive runoff from undeveloped watersheds. The study beaches were selected to represent a variety of geographical conditions and watershed sizes in Northern California. Five reference beaches were sampled between January 2016 and September 2017 for a total of 25‐30 sampling events, including 10 wet weather events, 10 winter dry events, and 10 summer dry events. The number of samples collected was admittedly small for characterizing variable bacteria concentrations but was deemed sufficient for providing initial information relevant to management questions. At each beach, samples were collected from an ocean site in the surf zone and from a freshwater site in the watershed draining to the beach. Samples were analyzed for total coliform, fecal coliform, Escherichia coli (E. coli), enterococci (ocean sites only), as well as a human‐specific genetic marker (human Bacteroides HF183).

Microparticles, Microplastics, and PAHs in Bivalves in San Francisco Bay

San Francisco Estuary Institute (SFEI) | November 15th, 2019

Microplastic Contamination in San Francisco Bay - Fact Sheet

San Francisco Estuary Institute (SFEI) | November 2nd, 2015

Microplastic contamination in the San Francisco Bay, California, USA

Marine Pollution Bulletin (Elsevier) | August 15th, 2015

Despite widespread detection of microplastic pollution in marine environments, data describing microplastic abundance in urban estuaries and microplastic discharge via tr

Despite widespread detection of microplastic pollution in marine environments, data describing microplastic abundance in urban estuaries and microplastic discharge via treated municipal wastewater are limited. This study presents information on abundance, distribution, and composition of microplastic at nine sites in San Francisco Bay, California, USA. Also presented are characterizations of microplastic in final effluent from eight wastewater treatment plants, employing varying treatment technologies, that discharge to the Bay. With an average microplastic abundance of 700,000 particles/km2, Bay surface water appears to have higher microplastic levels than other urban waterbodies sampled in North America. Moreover, treated wastewater from facilities that discharge into the Bay contains considerable microplastic contamination. Facilities employing tertiary filtration did not show lower levels of contamination than those using secondary treatment. As textile-derived fibers were more abundant in wastewater, higher levels of fragments in surface water suggest additional pathways of microplastic pollution, such as stormwaterrunoff.

Microplastic Monitoring and Science Strategy for San Francisco Bay

San Francisco Estuary Institute (SFEI) | February 1st, 2017

Microplastic is commonly defined as plastic particles smaller than 5 mm. In 2015, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) conducted a

Microplastic is commonly defined as plastic particles smaller than 5 mm. In 2015, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) conducted a special study to measure microplastic in treated wastewater effluent and Bay surface water. Bay surface water appeared to have higher microplastic levels than other urban water bodies sampled in North America, such as the Great Lakes and Chesapeake Bay. Microbeads derived from personal care products and tiny fibers, a portion of which were likely derived from synthetic clothing, were recovered from all nine Bay sites. Tiny particles, primarily fibers, were also detected in treated effluent from Bay Area facilities; not all of these particles are known to be plastic. These findings received considerable media attention and catalyzed state and federal policy shifts. 

Microplastic Monitoring and Science Strategy for the San Francisco Bay

San Francisco Estuary Institute (SFEI) | February 7th, 2017

Microplastic is commonly defined as plastic particles smaller than 5 mm. In 2015, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) conducte

Microplastic is commonly defined as plastic particles smaller than 5 mm. In 2015, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) conducted a special study to measure microplastic in treated wastewater effluent and Bay surface water. Bay surface water appeared to have higher microplastic levels than other urban water bodies sampled in North America, such as the Great Lakes and Chesapeake Bay. Microbeads derived from personal care products and tiny fibers, a portion of which were likely derived from synthetic clothing, were recovered from all nine Bay sites. Tiny particles, primarily fibers, were also detected in treated effluent from Bay Area facilities; not all of these particles are known to be plastic. These findings received considerable media attention and catalyzed state and federal policy shifts. In 2016, the RMP authorized a special study to develop a strategy for continued study of microplastic in San Francisco Bay. To form this strategy, the RMP convened stakeholders to articulate management questions specific to microplastic pollution, and then conducted a one-day workshop that brought together stakeholders and microplastic experts to develop an understanding of the state of the science on this emerging contaminant, and determine consensus priorities for future work. The resulting strategy document provides: • an overview of microplastic science relevant to San Francisco Bay, • the management questions that will guide future work, • a summary of available sampling and analysis methods, and • a multi-year plan for studies that would provide answers to the management questions. The monitoring and management of both macro- and microplastic are issues that extend beyond the scope of the RMP. In this document, we seek to identify data gaps, next steps, and strategic partners who can help provide information and resources to inform management decisions. This Microplastic Strategy will be refined and adjusted in years to come based on advances in understanding and changes in the sources and management of plastic pollution.

Microplastic pollution is widely detected in US municipal wastewater treatment plant effluent

Environmental Pollution (Elsevier) | August 27th, 2016

Municipal wastewater effluent has been proposed as one pathway for microplastics to enter the aquatic environment. Here we present a broad study of municipal wastewater t

Municipal wastewater effluent has been proposed as one pathway for microplastics to enter the aquatic environment. Here we present a broad study of municipal wastewater treatment plant effluent as a pathway for microplastic pollution to enter receiving waters. A total of 90 samples were analyzed from 17 different facilities across the United States. Averaging all facilities and sampling dates, 0.05 ± 0.024 microparticles were found per liter of effluent. Though a small value on a per liter basis, even minor municipal wastewater treatment facilities process millions of liters of wastewater each day, yielding daily discharges that ranged from ∼50,000 up to nearly 15 million particles. Averaging across the 17 facilities tested, our results indicate that wastewater treatment facilities are releasing over 4 million microparticles per facility per day. Fibers and fragments were found to be the most common type of particle within the effluent; however, some fibers may be derived from non-plastic sources. Considerable inter- and intra-facility variation in discharge concentrations, as well as the relative proportions of particle types, was observed. Statistical analysis suggested facilities serving larger populations discharged more particles. Results did not suggest tertiary filtration treatments were an effective means of reducing discharge. Assuming that fragments and pellets found in the effluent arise from the ‘microbeads’ found in many cosmetics and personal care products, it is estimated that between 3 and 23 billion (with an average of 13 billion) of these microplastic particles are being released into US waterways every day via municipal wastewater. This estimate can be used to evaluate the contribution of microbeads to microplastic pollution relative to other sources (e.g., plastic litter and debris) and pathways (e.g., stormwater) of discharge.

Microplastic Strategy Update on behalf of the Regional Monitoring Program (RMP) for Water Quality in San Francisco Bay

San Francisco Estuary Institute (SFEI) | December 2nd, 2019

Based on the detection of microplastics in San Francisco Bay surface water and Bay Area wastewater effluent in 2015, the Regional Monitoring Program for Water Quality in

Based on the detection of microplastics in San Francisco Bay surface water and Bay Area wastewater effluent in 2015, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) convened a Microplastic Workgroup (MPWG) in 2016 to discuss the issue, identify management information needs and management questions (MQs), and prioritize studies to provide information to answer these management questions. The MPWG meets annually to review on-going microplastic projects and to conduct strategic long-term planning in response to new information in this rapidly evolving field.

Microplastics from Tire Particles in San Francisco Bay

San Francisco Estuary Institute (SFEI) | March 14th, 2022