Contents

State of Washington, Department of Ecology Research Related to 6PPD Stormwater Best Management Practices

Client: State of Washington, Department of Ecology, WA
Role: Project Manager / Scientific Lead
Timeline: August 2024 – Present

Leading comprehensive research to identify factors affecting 6PPD-quinone concentrations in stormwater, including crumb rubber use, street sweeping frequencies, traffic intensities, land use, and BMP type. Responsibilities include developing the Study Plan and Quality Assurance Project Plan, coordinating monitoring activities, communicating with participating municipalities, conducting literature reviews, performing statistical analysis, and delivering detailed reports. This project addresses a critical emerging contaminant affecting salmon populations in the Pacific Northwest.

County of San Diego Microbial Source Tracking Work Plan Development

Client: County of San Diego, CA
Role: Scientific Advisor/Project Manager
Timeline: April 2024 – Present

Developed a comprehensive Microbial Source Identification Work Plan to fulfill requirements of the Time Schedule Order (R9-2024-0010) for the Bacteria TMDL. The plan details additional monitoring and source investigation requirements with the goal of meeting final dry weather Water Quality Based Effluent Limitations. Created a strategic framework that includes historical compliance data analysis, evaluation of previous MST efforts, and an adaptive microbial source identification approach to achieve compliance.

City of Vista Continuous Low Flow Monitoring

Client: City of Vista, CA
Role: Project Manager
Timeline: July 2024 – Present

Managing continuous dry and wet weather flow monitoring at Guajome Lake. Responsibilities include field reconnaissance, equipment installation and maintenance, flow monitoring, flow calculation, data collection and comprehensive QA/QC. This project provides critical data for understanding hydrological patterns and potential contaminant transport pathways.

City of Vista MS4 Outfall Monitoring Program Support

Client: City of Vista, CA
Role: Project Manager
Timeline: July 2024 – Present

Providing comprehensive support for monitoring persistently flowing MS4 outfalls. Coordinating with laboratories, collecting and validating data, performing long-term data analysis, and prioritizing outfalls based on compliance needs. This work helps the City meet regulatory requirements while identifying critical areas for potential remediation efforts.

Riverside County Flood Control District Santa Margarita River WQIP Wet Weather Monitoring

Client: Riverside County Flood Control District, CA
Role: Project Manager
Timeline: July 2024 – Present

Conducting wet weather monitoring for the Santa Margarita River Water Quality Improvement Plan at mass loading stations and MS4 outfall locations. Responsibilities include field reconnaissance, equipment installation, flow monitoring, automated sample collection, data collection, and CEDEN data formatting and uploading of field, chemistry, and toxicity data. This program supports compliance with MS4 permit requirements while providing insights into contaminant sources and transport dynamics.

As-Needed Water Quality Monitoring Project Consulting Services

Client: County of San Diego, CA
Role: Program Manager
Timeline: September 2018 – December 2023

Served as the primary liaison for the County of San Diego’s As-Needed Water Quality Monitoring Project consulting services contract. Managed 53 task orders for special studies across all watersheds in the County, including MST stormwater assessments, HF183 dry weather outfall monitoring, BMP effectiveness studies, and continuous flow monitoring. Deliverables included meeting support, field monitoring implementation, data review and statistical analysis, and comprehensive reporting.

Water Quality Monitoring and Reporting Program

Client: County of San Diego and Regional Copermittees, CA
Role: Project Manager and Scientific Advisor
Timeline: July 2019 – December 2023

Managed the compliance Bacteria TMDL monitoring in San Luis Rey River (SLR) and San Diego River (SDR), SDR Bacteria TMDL follow-up studies, turf replacement study with SCCWRP, Bight13 microbiology study at SLR, and SLR River and San Diego River MST studies. Provided scientific advisory support and laboratory direction for special studies and source identification investigations. Supported negotiations with the San Diego Regional Board regarding statistical and data analysis related to the Time Sensitive Order for the Bacteria TMDL.

As-Needed Environmental Analytical Services

Client: San Diego Unified Port District, CA
Role: Program Manager
Timeline: January 2022 – December 2023

Served as the primary client liaison for the Port of San Diego, providing oversight for all task orders under the as-needed environmental analytical services contract. Coordinated analytical services, ensured quality control, and maintained effective communication between the Port and the project team.

Annual Bacteria TMDL Reporting for San Diego River and San Luis Rey River watersheds

Client: County of San Diego and Regional Copermittees, CA
Role: Project Manager
Timeline: July 2023 – December 2023

Managed the development and submission of TMDL Annual Reports for the San Luis Rey River and San Diego River watersheds. This included data compilation and analysis, trend assessment, compliance evaluation, and comprehensive reporting of monitoring results and implementation activities.

Carlsbad WMA WQIP Monitoring Program

Client: City of San Marcos, CA
Role: Scientific Advisor
Timeline: January 2023 – December 2023

Reviewed and contributed to data analysis and reporting for the stressor identification study in Agua Hedionda and Batiquitos Lagoons. The study was conducted in response to SQO assessments completed during the Southern California Regional Bight Monitoring Program. Provided expertise on toxicity identification and evaluation (TIE) analysis to determine chemical causes of toxicity in benthic organisms and evaluation of benthic infaunal community composition.

Loma Alta Slough Long-Term Nutrient Water Quality Monitoring

Client: City of Oceanside, CA
Role: Scientific Advisor
Timeline: January 2016 – December 2023

Supported statistical data analysis (trend and correlation analysis) and reporting for the long-term nutrient water quality monitoring program in Loma Alta Slough. The monitoring included watershed stream inflow and nutrient loading, slough macroalgal cover and biomass, slough water quality nutrient levels, and dissolved oxygen concentrations. Results were used to evaluate and demonstrate water quality improvements achieved through MS4 Permit compliance actions and to track progress toward numeric targets and phosphorus loading reductions outlined in Resolution R9-2014-0020.

City of Oceanside Utilities NPDES Support

Client: City of Oceanside, CA
Role: Project Manager
Timeline: May 2020 – December 2023

Supported the City in negotiations with the San Diego Regional Board regarding NPDES permit requirements. Conducted sample analysis and data reporting to assist with compliance efforts and regulatory interactions. Provided technical expertise to navigate complex regulatory requirements and develop effective compliance strategies.

Marina del Rey Coordinated Integrated Monitoring Program (CIMP)

Client: Los Angeles County Flood Control District, CA
Role: Scientific Advisor
Timeline: February 2017 – December 2023 oring program that included stormwater and dry weather water quality monitoring, sediment, fish, and mussel tissue monitoring. Contributed to reporting and data quality control for multiple surveys throughout the year to meet NPDES Permit and TMDL requirements.

Microbial Source Identification Study at Mothers Beach Marina del Rey

Client: LA County Department of Beaches and Harbors, CA
Role: Project Manager
Timeline: April 2022 – October 2022 (WESTON)

Managed a targeted microbial source tracking study at Mother’s Beach in Marina del Rey. Tasks included preparation of the study plan, coordinating monitoring at five locations over a six-week period, overseeing sample analysis, and developing the final report with recommendations for addressing identified contamination sources.

Comprehensive Human Waste Source Reduction Strategy (CHWSRS), Tier 3 Source Identification Implementation

Client: Orange County Department of Public Works, CA
Role: Scientific Advisor
Timeline: June 2020 – December 2020 (WESTON)

Contributed to the development and implementation of the Tier 3 source identification component of the CHWSRS program for South Orange County permittees. The study involved assessment of existing data, prioritization of monitoring locations, field monitoring implementation, and data interpretation to identify and address human waste contamination sources.

Magnolia MST Study

Client: Riverside County Flood Control and Water Conservation District, CA
Role: Scientific Advisor
Timeline: June 2020 – October 2020 (WESTON)

Developed the study design for a fast-track Microbial Source Tracking investigation. Provided reporting support and presented findings to stakeholders. The expedited timeline required efficient coordination and innovative approaches to data collection and analysis while maintaining scientific rigor.

SLR River Wet Weather Microbial Source Tracking Study Phase I and II

Client: County of San Diego, CA
Role: Project Manager
Timeline: July 2017 – June 2019 (WESTON)

Led this multiphase microbial source tracking study focused on the San Luis Rey River watershed. Managed the installation of sampling stations for flow-weighted automatic wet weather sampling, coordinated wet weather monitoring activities, and oversaw laboratory and reporting services. The primary goal was identifying human fecal contamination sources in the watershed to enable targeted mitigation efforts.

Inner Cabrillo Beach Bacteria TMDL and Natural Source Exclusion

Client: Port of Los Angeles, CA
Role: Project Manager
Timeline: February 2015 – June 2022 (WESTON)

Managed the first-ever Natural Source Exclusion program in Southern California, assisting the Port of Los Angeles during negotiations with the Los Angeles Regional Board. The program included ongoing studies to quantify the sources of bacteria loading to the beach and appropriately allocate sources. Conducted Quantitative Microbial Risk Assessment (QMRA) analysis to assess human health risks based on pathogen evaluations linked to predominant bacteria sources. Provided technical support regarding a time-sensitive order issued by the Los Angeles Regional Board and participated in a Technical Advisory Committee for a SCCWRP-performed CBI grant-funded MST and QMRA study.

Molecular Source Tracking Study at Shelter Island Shoreline Park (SISP)

Client: Unified Port District of San Diego, CA
Role: Project Manager
Timeline: February 2016 – May 2017 (WESTON)

Assisted the Port in implementing an initial MST study focused on identifying sources contributing to bacterial loading at the Shelter Island swim beach. Oversaw development of the sampling and analysis plan, managed dry weather monitoring activities, trained Port staff in molecular sampling methods, coordinated quantitative polymerase chain reaction (qPCR) laboratory analysis, ensured QA/QC protocols, and delivered comprehensive project reporting.

Oxford Retention Basin Multiuse Enhancement Project (MEP) Post-Construction Monitoring

Client: Los Angeles County Department of Public Works, CA
Role: Scientific Advisor
Timeline: January 2018 – December 2022 (WESTON)

Provided scientific advisory support to assess the effectiveness of the Multiuse Enhancement Project in improving environmental conditions at the Oxford Retention Basin compared to pre-project conditions. Tasks included evaluating data, performing statistical analysis, and supporting report development to document environmental benefits achieved through the project implementation.

UCLA Run-On Special Study

Client: University of California, Los Angeles, CA
Role: Scientific Advisor and Laboratory Director
Timeline: July 2016 – June 2018 (WESTON)

Consulted with the project team on protocols and sampling approaches to evaluate potential bacterial sources running onto the UCLA campus. Oversaw laboratory quantification testing of the human marker (HF183) in dry weather samples and supported supplemental testing of wet weather samples collected during storm events. The study helped identify potential contamination sources affecting the university grounds.

Loma Alta Slough Microbial Source Tracking Study, Clean Beaches Initiative (CBI) Grant

Client: City of Oceanside, CA
Role: Project Manager
Timeline: January 2016 – June 2018 (WESTON)

Implemented an MST study funded by a Clean Beaches Initiative Grant at Loma Alta Slough. Managed field monitoring, client communications, and qPCR laboratory analysis. Led the qPCR method validation study, data analysis, and reporting. Successfully navigated limited timeframe and budget constraints through strategic power analysis and rigorous scheduling to deliver actionable information for prioritizing mitigation efforts.

Leaching Study Dust Suppressant Products

Client: Confidential Client, Carlsbad, CA
Role: Project Manager
Timeline: April 2017 – February 2018 (WESTON)

Managed a study to evaluate potential toxicological impacts of dust suppressant products designed for dry lake beds. Responsibilities included study planning, execution, and comprehensive reporting of findings to assess environmental safety and performance characteristics of various dust control formulations.

 

Quantification of Pathogens and Sources of Microbial Indicators for Quantitative Microbial Risk Assessment in Recreational Waters

Water Environment Research Foundation , PATH1R08 Laboratory Manager. Responsibilities included contributions to development of filtration and extraction methods, quality control of molecular analyses for human pathogens and MST markers in source water samples, and data analysis of obtained results.

Assessing the Effectiveness of Improved Sanitation on Diarrhoea and Helminth Infection: a cluster randomized controlled trial in rural India

MST sub-study, Bill & Melinda Gates Foundation, Molecular Biology Lead. Designed monitoring plan and coordinated two-year sampling effort. Technical lead on use and quality control of pathogen and MST assays in surface water, stormwater runoff, hand rinses, and groundwater samples.

Potential for Pathogen Growth, Fecal Indicator Growth and Phosphorus Release under Clam Removal Barriers in the Lake Tahoe Basin

US Forest Service, Molecular Biology Lead. Contributed to study design and quality control of microbiological analyses.

Wastewater Reuse in Israel

Timeline: 2009-2012
Collaborators:

• Zuckerberg Institute for Water Research, Ben Gurion University of the Negev, Israel
• Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, USA
• The Agricultural Research Organization (ARO), Ministry of Agriculture and Rural Development, Israel

Role: Scientific Advisor regarding pathogen detection

Full Title: Science-based monitoring for produce safety: Comparing indicators and pathogens in water, soil, and crops

 

Background:

Contamination of irrigation water, soil and edible crops with pathogens is a significant and growing health concern worldwide. Outbreaks of disease due to consumption of produce that has been contaminated with human-derived viruses, bacteria, and protozoa have been documented in developing as well as developed nations (Sivapalasingam et al 2004; Doyle & Erickson 2008). Moreover, diminishing sources of freshwater supplies needed for irrigation pose a serious challenge to agriculture practices. In arid and semi-arid regions (such as Israel and portions of the United States), freshwater supplies are extremely limited, and as populations and the demand for freshwater have grown in the municipal sector, agricultural policy has had to adapt. In Israel, over the past three decades this adaptation has come in the form of reducing overall freshwater available to the agricultural sector and increasing the amount of treated wastewater supplied to farmers. At present, 91% of all municipal sewage in Israel is treated, 73% of which is reclaimed [versus 2.5% in the United States (National Academy of Science, 1996)], contributing roughly one-fifth of Israel’s total water supply. Water shortage and the deterioration in the quality of freshwater resources in Israel have made necessary a national policy recommending reuse of practically all municipal wastewater in order to supply a major part of agricultural water demand (Brenner et al., 2000).

The environmentally sustainable approach of using treated wastewater for irrigation can lead to contamination of produce with fecal pathogens that may remain in treated water. Irrigation with wastewater has been found to be associated with a high risk of fecally derived bacterial, parasitic and viral infections (Shuval et al., 1986; Doyle and Erickson 2008; Nygard et al., 2008). Partial as well as advanced treated wastewater used for irrigation has been implicated as a source of infection with intestinal parasites and as cause of chronic diarrhea, particularly in children (Cifuentes, 1998; Peasey, 2000; Blumenthal et al., 2003). Historically, water quality monitoring guidelines have targeted fecal indicator bacteria instead of fecal pathogens due to the simpler and cheaper methods involved. However, numerous studies have shown that the presence of fecal indicators in wastewater does not always correlate with the presence of disease-causing microorganisms (Payment et al., 2001; Harwood et al., 2005; Ottoson et al., 2006). Bacterial pathogens including Salmonella, Campylobacter, Vibrio, E. coli O157:H7, protozoal pathogens such as Cryptosporidium and Giardia, and viruses such as adenoviruses and enteroviruses may be present in wastewater effluents, and waterborne infections with these pathogens have been known to cause severe disease in humans (Mead et al, 1999; Nachamkin, 1999; Tison, 1999;). The lack of correlation between indicators of fecal pollution that are currently used in microbiological monitoring standards of irrigation waters and the presence of these organisms on produce presents a serious risk to public health.
In addition to direct contamination of produce with contaminated irrigation water, soil can serve as a vehicle for transferring pathogens to produce because some pathogens may persist in soil following irrigation of the soil matrix with wastewater, as well as via fertilization practices. Pathogens within soil may contaminate crops directly, when heavy rain or sprinkler irrigation cause leaf splash, or indirectly, by penetrating the plant tissues. Fecal pathogens are known to survive for long periods and in some instances propagate in the soil until crops are planted (Bernstein et al., 2007a; Heaton and Jones, 2008), increasing the likelihood of crop contamination during the plant’s growth cycle or through the harvest process.
The ability of fecal pathogens to persist on crop tissues including the leaf surface (phylloplane), the root, and the fruit, has drawn increasing attention following recent produce-related disease outbreaks (Doyle and Erickson, 2008; Heaton and Jones, 2008). Accumulation of pathogens on crop tissues increases the chance of an infectious dose remaining at the time of produce consumption. Enteropathogens, specifically E. coli and Salmonella, in irrigation water were shown to be taken up by the root systems and enter the edible portion of lettuce (Bernstein et al., 2007b), apple (Burnett et al 2000), tomato (Guo et al., 2001) and maize (Bernstein et al., 2007c). The uptake of pathogenic viruses, protozoa and opportunistic pathogens such as Pseudomonas aeruginosa by crops were poorly investigated.
In addition, the actual correlation between levels of indicator fecal organisms in irrigation water and presence of pathogens on plant tissues is largely unknown. An effluent standard based on a single fecal indicator is thus insufficient. We aim to investigate a suite of indicators and pathogens in an effort to promote science-based management as improved guidelines are developed.
Findings from the study will have immediate application potential to agriculture management and public health policy decisions regarding optimal microbial sampling schemes needed to protect consumers from exposure to disease-causing microorganisms from fruit and vegetables.
The overall goal of this research is to evaluate the correlation between fecal indicator organism and presence of pathogens in irrigation water, soil, and plant tissues. Towards this end, we have identified three objectives to better understand the relationship between levels of fecal indicator bacteria and presence of pathogenic fecal bacteria, protozoa, and viruses in reclaimed wastewater and the soil and crops that are irrigated with these waters. Specifically, the project will evaluate if current monitoring techniques that target fecal indicator organisms accurately predict the presence of fecal pathogens on produce using wastewater irrigated tomatoes as our model plant cultivated in plots constructed for the purpose of this project.

 

Avalon Bay Water Quality Improvement Project

Timeline: 2009
Client/Partner: the University of California, Irvine – Prof. Stanley Grant
Study Location: City of Avalon
Role: Lab Manager

Background:

The City of Avalon, located on Catalina Island, is a recreational destination for boaters, fishermen, divers, beachgoers, and other ocean-oriented visitors. In 1999 the County of Los Angeles began testing Avalon Bay for fecal indicator bacteria in accordance with AB 411. These test results frequently exceeded California single-sample standards for fecal indicator bacteria in coastal bathing waters, and as a result beaches in Avalon have been frequently posted as unfit for swimming.
In response to these test results, a series of studies and mitigations efforts were undertaken. In 2000, Ms. Alison Davis in Jed Fuhrman’s laboratory at USC was hired to conduct a microbial source tracking study, to determine if there was evidence of human fecal pollution in Avalon Bay. This study, which was very small in scope, found no evidence of human viruses in Avalon Bay. Based on the results of this study, the City concluded that the fecal indicator bacteria problem in Avalon Bay was due to fecal material produced by birds, in particular pigeons.
Accordingly, the City focused on controlling bird populations in and around the City. In 2001, the City received a $500,000 grant from the State of California’s Clean Beaches Initiative to further investigate the water quality problem in Avalon Bay, and pursue mitigation measures.
This grant had three goals: 1) provide baseline monitoring information for water quality in Avalon Bay; 2) identify possible sources of fecal indicator bacteria in the Bay, 3) conduct microbial source tracking studies, and 4) characterize circulation in Avalon Bay.

Based on the study results, the City implemented the following mitigation measures:
a) Sewer mains and manholes in the first three blocks from the waterfront were slip-lined and sealed; this effort was completed in May, 2002.
b) Bird control measures were intensified; this ongoing effort was initiated in 2001.
c) Plumbing under the wharfs was repaired and a regular twice per year inspection program initiated.
d) Street wash down procedures were modified to prevent run-off.
e) Sewer laterals in the first three blocks from the waterfront were repaired and sealed; this effort was initiated in May 2005 and completed in November 2005.

Unfortunately, the mitigation measures described above did not result in substantial improvement in shoreline water quality, with the result that the main beach areas in Avalon Bay continue to be posted as unfit for swimming. Given the City’s substantial efforts to control contamination of the Bay from boats, dry weather runoff, bird droppings, and under wharf plumbing, attention has now focused on the possibility that sewage contaminated shallow groundwater is the primary cause of water quality impairment in Avalon Bay. In light of the above, the current Proposition 13 Clean Beaches Grant was funded to characterize the extent of
sewage-contaminated shallow groundwater; to conduct a pilot remediation study on sewage-contaminated shallow groundwater; to identify sources of fecal indicator bacteria (FIB) in ankle-
depth waters; and to improve sewer infrastructure.
UC Davis conducted laboratory analyses consistent with the MST monitoring plan outlined in the Work Plan for the Avalon Bay Water Quality Improvement Project.

Dr. Alexander Schriewer was responsible for the identification of fecal sources and human adenoviruses.

Epidemiological Study at Southern California Beaches

Timeline: 2008-2009
Collaborator/Organizer: Southern California Coastal Water Research Project (SCCWRP)
Funding Agency: CEE portion funded by the California Department of Transportation (Caltrans)
Study Locations:

  • Doheny State Beach, Dana Point, CA (June – September 2008)
  • Avalon Beach, Avalon, CA (June – September 2008)
  • Surfrider Beach, Malibu, Ca (June – September 2009)

Background and Objectives (from planning document):

A number of epidemiology studies that have demonstrated a relationship between indicator bacteria and health risk, but they have been mostly conducted on beaches impacted by point sources with known human fecal contributions. Few studies have examined this relationship at beaches where non-point sources are the dominant fecal input source.
To address this, SCCWRP organized and conducted three epidemiology studies between 2007 and 2009. The first was at Doheny State Beach in Dana Point, which is a site where the bacterial inputs are thought to be primarily from nonhuman sources (birds, urban runoff). The second was at Avalon Beach on Catalina Island, where leaking sewage infrastructure is believed to be the predominant bacterial source. The third is Surfrider Beach in Malibu, where local septic systems, birds, and urban runoff are all believed to contribute to the bacterial load.
Together, these sites allow investigation of indicator/health-risk relationships across a spectrum of bacterial input sources with a varying degree of human fecal contribution.

The study focused on three primary questions:
1) Did water contact increase the risk of illness during the two weeks following exposure to water?
2) Among those individuals with water contact, were there associations between illness and measured levels of traditional water quality indicators?
3) Among those individuals with water contact, were there associations between illness and measured levels of non-traditional water quality indicators?

The study was conducted using a prospective cohort design, in which swimmers (and non-swimmers) are monitored for water exposure while at the beach and surveyed for illnesses that occur in the two weeks subsequent to their beach visit. They were queried with respect to gastrointestinal, respiratory, dermatological, ear, eye, and other nonspecific symptoms.
Water quality was assessed at the same times and locations as beachgoer recruitment in order to assess swimmer exposure. Measurements included both traditional and non-traditional indicators. Traditional FIB methods quantify total coliform, fecal coliform, and enterococcus using membrane filtration. Enterococcus was also measured using the Enterolert chromogenic substrate method. Nontraditional measurements included rapid methods for quantifying enterococcus and E. coli, host-specific Bacteroidales, Bacteroides thetaiotamicron, adenovirus, norovirus, and coliphage (somatic and F+), among others. SCCWRP took a collaborative approach, supplying samples to numerous investigators who have developed a variety of methods for new indicators since the marginal cost for additional sample collection is small relative to the fixed cost of the epidemiological data collection and analysis.

Alexander Schriewer was responsible for all processes pertaining to the laboratory analysis, compilation, and submission of results regarding host-specific Bacteroidales, bird-specific Catellicoccus marimmamalium marker, Adeno- and Enteroviruses to SCCWRP. These analyzes at the UCD, Dr. Wuertz laboratory are exclusively funded by the California Department of Transportation (Caltrans).

Collaborators for the SCCWRP epidemiological study are from:

  • Center for Genome Research & Biocomputing, Oregon State University
  • Department of Biological Sciences, University of Southern California
  • Department of Biological Sciences, University of Southern Mississippi
  • Department of Civil and Environmental Engineering, University of California at Davis
  • Department of Environmental Sciences and Engineering at University of North Carolina at Chapel Hill
  • Department of Integrative Biology, University of South Florida
  • Institute of Marine Sciences at University of North Carolina at Chapel Hill
  • U.S. Geological Survey (USGS) Ohio Water Science Center

 

Evaluation of Alternative Indicator Methods for Use in the Epidemiology Study

Timeline: 2007
Collaborator: Southern California Coastal Water Research Project (SCCWRP)
Study Location: Laboratory of the Orange County Sanitation District Laboratory (OCSD)
Role: Lab Manager

Background:

The Southern California Coastal Water Research Project (SCCWRP), in partnership with the Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET), was planning to conduct an epidemiology study of swimming-related illness (see section 10) in summer 2007 at Doheny State Beach and other beaches. Part of the study involved measuring new indicators, most of which have been anticipated to be present at much lower density than historically measured fecal indicator bacteria (FIB). Moreover, the principal fecal sources at Doheny Beach were thought to be urban runoff and birds. Even though more than half of the samples previously taken at the site exceed enterococcus standards, it was thought possible that many of the samples collected during the epidemiology study will contain low counts of the alternative targets.
Interpreting outcomes from the epidemiology study required the ability to confidently differentiate non-detects of target organisms attributable to low density at the study site from a recovery issue associated with the new measurement method. To better understand method sensitivity for the new measurement methods and measurement targets, SCCWRP wanted to conduct a methods evaluation study prior to the epidemiology study. Results from the evaluation study will provide participants an opportunity to refine their methods before they begin processing irreplaceable field samples from the epidemiological study.
A secondary objective of the study was to train SCCWRP personnel in the sample processing and analysis techniques that will be performed during the epidemiological study. More than 20 water quality measurement methods have been included in the epidemiological study. For most of these, SCCWRP will be responsible for collecting, filtering, storing and shipping filters to our partners at external laboratories. While some methods share a common filtration or DNA extraction technique, most have been developed independently and require individual filtrations or unique sample manipulations. SCCWRP was committed to performing each sample preparation and/or analysis protocol in a manner that ensures quantification of a target if it is present in the sample. This study allowed SCCWRP personnel to interact with the method
developer to ensure familiarity with each method in advance of the epidemiological study.
Alexander Schriewer participated in this study in April 2007 as a representative of the Dr. Wuertz laboratory and its methods for the following epidemiological study.

Publication:

Griffith, J.F., Cao, Y., McGee, C.D., Weisberg, S.B., 2009. Evaluation of rapid methods and novel indicators for assessing microbiological beach water quality. Water Research 43, 4900-4907.

Monitoring and Mitigation to Address Fecal Pathogen Pollution along California Coast

Timeline: 2007-2008
Client/Partner: Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis.
Study Location: Rivers and Estuaries along Monterey Bay
Role: Lab Manager

Background:

The central California coast has an especially rich tourism industry, attracted by the diverse estuarine and marine resources of the region, including extensive sandy beaches and scenic, rocky coastlines. In addition, this area offers ample opportunity for water-contact sports such as swimming, surfing, kayaking, and wildlife viewing. Fisheries also exist locally for the harvest of marine-origin foods for human consumption including shellfish, crustaceans, squid, fish, and kelp products. Fecal pollution by terrestrial-origin bacteria and parasites is significantly impairing coastal beneficial uses throughout California by causing beach closures and human disease. Between 2000 and 2002, the number of days of beach closure for Santa Cruz and Monterey County almost tripled, from 3.9 to 11.8 beach-mile days. This finding is substantiated by recent CCLEAN data indicating that most coastal streams between the San Lorenzo River and Salinas River have exceeded the proposed Basin Plan Amendment for concentrations of E. coli (CCLEAN, 2005).

Fecal-origin biologic pollutants also appear to be negatively impacting the health of the southern sea otter. As a federally protected threatened species, the survival and maintenance of sea otters must be supported by the quality of California coastal waters. Despite decades of protection, the southern sea otter population has demonstrated an alarmingly slow rate of recovery. Elevated mortality due to infectious disease, including disease associated with terrestrial-origin protozoa and bacteria appears to be a main factor limiting southern sea otter recovery (Kreuder et al., 2003; Thomas and Cole, 1996). Several pathogens isolated from dead and dying sea otters appear to have anthropogenic origins and could be associated with coastal development, wetlands ablation, and coastal wastewater discharge (Conrad et al., 2005; Miller et al., 2002, 2005c, 2006). Many of these sea otter pathogens are similar or identical to fecal pathogens that cause illness in humans. Collectively these data indicate significant impairment to the water contact recreation beneficial use and sea otters along the central California coast, though contributing sources and sustainable solutions to mitigate fecal pollution are not well understood. The recipients of the benefits from this project are all users of streams, rivers and near-shore marine waters that are impaired by fecal pathogens. The information provided by this project is especially useful to resource managers for guiding implementation actions needed to reduce loads of fecal pathogens. As part of the environmental monitoring component, this project measured indicator bacteria and fecal pathogens in streams, sewage, and mussels to determine which watersheds and times of the year contribute the most to loadings of fecal pathogens and how the incidence of fecal pathogens corresponds to the concentrations of indicator bacteria.

Dr. Alexander Schriewer was responsible for all processes with regards to the laboratory analysis of microbial source tracking markers, compilation and submission of results, and QA/QC. Moreover he compiled the complete data and wrote a peer-reviewed journal publication.

Publication:

Schriewer A., Miller W.A., Byrne B.A., Miller M.A., Conrad P.A., Hardin D., Yang H-H, Oates S., Chouicha N., Melli A., Jessup D., Wuertz S. (2010). Bacteroidales as a predictor of pathogens in surface waters of the central California coast. Applied and Environmental Microbiology, 76(17), 5802-5814.

Toxoplasma Quantification Study

Timeline: 2007
Client/Partner: Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis.
Study Location: Laboratory Study
Role: Lab Manager

Background:

While reports on waterborne infections with Toxoplasma gondii are emerging worldwide, the detection of this zoonotic parasite in water remains challenging. Lack of standardized and quantitative methods for the detection of T. gondii oocysts in water also limits research on the transport and fate of this pathogen through aquatic habitats. In this project, the ability of hollow-fiber ultrafiltration and capsule filtration was compared to concentrate oocysts in spiked tap water, fresh surface water, and seawater samples. Detection of T. gondii oocysts in concentrated samples was achieved using molecular methods, as well as visually via epifluorescent
microscopy. In addition to oocysts, water samples were spiked with T. gondii surrogate microspheres, and detection of microspheres was performed using flow cytometry and epifluorescent microscopy. Results demonstrate that both water concentration methods followed by microscopy allowed for quantitative detection of T. gondii oocysts and surrogate microspheres. For T. gondii oocysts, microscopy was more sensitive than TaqMan and conventional PCR, and allowed for detection of oocysts in all water samples tested. Compared with flow cytometry, microscopy was also a more cost-efficient and precise method for detection
of fluorescent surrogate microspheres in tap, fresh and seawater samples. This study describes a novel approach for quantitative detection of T. gondii oocysts in drinking and environmental water samples. The techniques described for concentrating and detecting surrogate microspheres have broad application for evaluating the transport and fate of oocysts, as well as the efficiency of water treatment methods for removal of T. gondii from water supplies.

Dr. Alexander Schriewer planned coordinated and executed the hollow-fiber ultrafiltration experiments as well as the sample and data analysis. He also contributed to a resulting peer reviewed publication.

Publication:

Shapiro, K., J. A. K. Mazet, A. Schriewer, S. Wuertz, H. Fritz, W. A. Miller, J. Largier, Conrad P.A. (2010). Detection of Toxoplasma gondii oocysts and surrogate microspheres in water using ultrafiltration and capsule filtration. Water Research (44), 893 – 903.

MST Comparison Study

Timeline: 2008
Client/Partner: CDM
Study Location: Santa Ana River Watershed, Laboratory
Role: Lab Manager

Background:

The first year implementation of the Urban Source Evaluation Plan (USEP) for the Middle Santa Ana River Total Maximum Daily Load (TMDL) included the collection of water samples from thirteen locations to evaluate urban sources of bacteria. Sample analysis for this USEP monitoring program included assays for Bacteroidales by two different laboratories: University of California at Davis (UCD) and the Orange County Water District (OCWD). Each laboratory used its own methods for the extraction and analysis of human, bovine and dog Bacteroidales markers. The objective of this single blind test was to evaluate the comparability of these laboratory methods for detecting and quantifying the presence of host-specific Bacteroidales markers. Several samples were produced and split into two subsamples which have been
analyzed by each laboratory: (1) aqueous grab samples with no spike of Bacteroidales; (2) aqueous grab samples spiked with various combinations of Bacteroidales markers (treatments);
and (3) aqueous blank samples. Aqueous grab samples will were collected from three sites that had been previously sampled under the USEP Monitoring Program.

As assigned Water Quality Laboratory QA Officer Dr. Alexander Schriewer was responsible for all processes pertaining to the laboratory analysis, compilation, and submission of results to CDM.

Microbial Source Tracking as Component of the Middle Santa Ana River (MSAR) Watershed TMDL Implementation Plan

Timeline: 2007-2008
Client/Partner: CDM
Study Location: Middle Santa Ana River Watershed
Role: Lab Manager

Summary:

Various waterbodies in the Middle Santa Ana River watershed are listed on the state 303(d) list of impaired waters due to high levels of fecal coliform bacteria. The Middle Santa Ana River (MSAR) Bacterial Indicator Total Maximum Daily Load (TMDL) was adopted by the Santa Ana Regional Water Quality Control Board (RWQCB) and approved by the State Water Resources Control Board (SWRCB) to address these fecal coliform impairments. Environmental Protection Agency (EPA) Region 9 approved the TMDL May 16, 2007. As part of the TMDL Implementation Plan, implementation of a bacteria monitoring program for the MSAR watershed was required. In addition, monitoring was incorporated into the implementation of activities designed to gather information regarding urban and agricultural sources of bacteria.
Microbial source tracking (MST) is an evolving watershed management tool for the development of TMDLs and the assessment of various inputs of fecal microorganisms into surface and groundwater from point source and nonpoint source runoff. MST based on Bacteroidales may serve as a management tool to validate the concept of allowable bacterial loads as specified by TMDL regulations. As part of the monitoring plan water quality framework, samples from 13 stations in the Middle Santa Ana River (MSAR) Watershed have been analyzed by UC Davis for microbial MST markers.

As assigned Water Quality Laboratory QA Officer Alexander Schriewer was responsible for all processes pertaining to the laboratory analysis and creation of the MST result database for CDM.

The study was conducted on behalf of:

  • Santa Ana Watershed Project Authority
  • San Bernardino County Stormwater Program
  • Riverside County Flood Control District
  • Cities of Chino, Chino Hills, Corona, Fontana, Montclair, Norco, Ontario, Rancho Cucamonga, Rialto, Riverside, and Upland
  • Milk Producers Council, and
  • Chino Watermaster Agricultural Pool

Report:

CDM (2008) Middle Santa Ana River Water Quality Monitoring Plan, April 03, 2008.

Los Angeles River Bacteria Source Identification Study

Timeline: 2007-2008
Client/Partner: AMEC
Study Location: Los Angeles River Watershed
Role: Lab Manager

Summary (Report Excerpt):

Recreational beneficial uses in the Los Angeles River (LA River) are impaired due to elevated concentrations of fecal coliform and E. coli. A Bacteria Total Maximum Daily Load (TMDL) for the LA River is being developed by the Los Angeles Region – Regional Water Quality Control Board (RWQCB) in cooperation with the Cleaner Rivers through Effective Stakeholder-led TMDLs (CREST) stakeholder group. In order to assist with dry weather source assessment and implementation of the TMDL, a Bacteria Source Identification (BSI) Study was developed and conducted through the CREST stakeholder process. The CREST stakeholder group involved in the Study included USEPA, RWQCB, City of Los Angeles and other watershed cities, LA County, Caltrans, Heal the Bay, Southern California Coastal Water Research Program (SCCWRP), the University of California, Davis, and others. The overall goal of the BSI Study was to increase the accuracy of the to-be-developed LA River Bacteria TMDL and improve the likelihood of success for future bacteria source control efforts associated with the TMDL’s implementation plan. That is, the study was designed to characterize the bacteria inputs to the LA River, support the development of a TMDL source assessment, and assist with prioritization of the types and locations of TMDL implementation actions. The BSI Study employed a microbial source tracking “toolkit” that assisted with identification of human versus non-human inputs including potentially-pathogenic human viruses. The dataset collected during the BSI Study is unprecedented within the LA River watershed in terms of the number and type of sampling locations, application of cutting-edge laboratory methods, and detail of gathered GIS information. In fact, the BSI Study is one of the most advanced microbial source tracking studies of urban runoff conducted to date.

Alexander Schriewer was the responsible contact person for sample processing, data analysis and reporting to create the source tracking and human pathogens database at the University of California, Davis.

Other companies and organizations involved:

  • Larry Walker and Associates
  • CH2MHill
  • CRG Marine Laboratories
  • CREST Stakeholders: USEPA, RWQCB, City of Los Angeles and other watershed cities, LA County, Caltrans, Heal the Bay, Southern California Coastal Water Research Program, the University of California, Davis and others

Report:

CREST (2008) Los Angeles River Bacteria Source Identification Study: Final Report, November 2008.

Santa Monica Bay Microbial Source Tracking Study

Timeline: October 2007 through April 2008
Client: California Department of Transportation (Caltrans)
Study Locations: Highway 1 (also SR-1) along Santa Monica Bay (California)
Role: PM/Lab Manager

Objectives:

Using the environmental toolkit, which was previously developed in the Dr. Wuertz Laboratory of the Department of Civil and Environmental Engineering at University of California, Davis,  the main goal of the monitoring study was to provide information about the extent of fecal pollution of stormwater representing non-commingled Caltrans highway runoff before it enters Santa Monica Bay within Jurisdiction 1 to 6 of the Santa Monica Bay Beaches Bacteria TMDLs. It is well known that traditional fecal indicator bacteria (FIB) tests for E. coli, fecal coliforms and enterococci can overestimate recent microbial pollution due to the ability of indicator organisms to survive and even multiply in environmental niches. In addition, the detection of human pathogens rarely correlates with the abundance of FIB in recreational waters. To address these concerns, microbial source tracking (MST) assays developed and validated previously were chosen to identify animal- or human-specific contributions. In addition, several molecular assays that target human viruses directly were applied to relate source tracking information to the presence of actual human pathogens. All samples were filtered and analyzed for the presence of human adenoviruses and enteroviruses as well as for host-specific genetic markers indicative of fecal pollution from cow-, dog-, or human fecal pollution or any fecal source of warm-blooded animals (universal marker). Traditional fecal indicator bacteria (FIB) measurements were performed side by side on each stormwater sample.

Report:

Schriewer A. and Wuertz, S. (2009). Santa Monica Bay Microbial Source Tracking Study, 2007-2008 Monitoring Season. Final report prepared for the Environmental Division of California Department of Transportation. Document #: CTSW-RT-09-168-23.1

Completion of Environmental Toolkit for Fecal Source Tracking and Pathogen Analysis in Stormwater

Timeline: 2006 – 2008
Client: California Department of Transportation (Caltrans)
Study Locations: Laboratory studies at the Department for Civil and Environmental Engineering, UC Davis
Role: PM/Lead Scientist

Background:

Under Section 303(d) of the 1972 Clean Water Act, states, territories, and authorized tribes are required to develop a list of water quality limited segments. These waters on the list do not meet water quality standards, even after point sources of pollution have installed the minimum required levels of pollution control technology. The California Water Board currently has many waters on this 303(d) list, and regional water boards are responsible for establishing and implementing TMDLs in these watersheds.

On the 2002 303(d) list are 258 water bodies with biological contaminants (i.e., pathogens, high coliforms, bacterial indicators, or Enterococci). Of these, most sites are listed with point/nonpoint sources or source unknown, but a total of 55 have runoff/storm water listed as a definitive source. Several other studies (Ackerman and Weisberg 2003, Boehm et al. 2002; Noble et al. 2003) have shown correlations between rainfall events and widespread pollution of fecal indicator bacteria at southern California coasts. While roadways contribute the largest proportion of impervious surfaces, one might assume their runoff is highly loaded with pathogens. However, there is no knowledge about the distribution of pathogenic pollution to different surfaces. Tools have to be found to quantify pathogens and land-use specific fecal loads that can produce reliable results independent of specific sample matrices.

The purpose of this Task Order was to complete a set of methods and protocols for environmental monitoring of stormwater. The objective was to be able to measure real pathogen loads in highway runoff and identify sources of microbial contamination. The microbial source tracking approach is based on the occurrence of bacterial cells of the order Bacteroidales that are indicative of feces originating from specific host organisms broadly attributable to human, domestic pet, cattle, or horse waste. Bacteroidales are among the key organisms currently targeted by the U.S. EPA for microbial source tracking.

Knowledge about decay rates of quantified targets is a key component. In situ experiments were conducted to assess the persistence of genetic markers in freshwater and seawater and the influence of light. This information will significantly increase the utility of monitoring data. Additionally, a conditional probability approach was used to develop a quantitative statistical model to provide confidence limits for reported microbial source tracking data.

Another specific goal of the task order includes the development of a suitable surrogate that can be added to stormwater samples and used to determine filtration efficiencies for the quantitative detection of protozoan pathogens like Cryptosporidium and Toxoplasma. Particularly, the presence of pathogens that are infective in low numbers accentuates the importance of reliable and sensitive test methods. For the optimization of the detection of pathogens and bacterial markers by qPCR suitable methods have to be found that ensure efficient nucleic acid extraction and quantification/detection. Knowledge about the affinity of pathogens to solids in the context of ultrafiltration is also missing. Therefore, the sorption of viruses and the question of whether pathogens and bacterial markers are lost due to association with solids is examined in this study. PCR inhibitors prevalent in natural samples such as humic acids can significantly interfere with the quantification of targets and even lead to false non-detects. Finally, methods to treat inhibitors have been reviewed and developed. Furthermore, the previously developed methods and processes were optimized in regard to sensitivity, recovery, and quantitation.

Publication:

Schriewer A., Wehlmann A. and Wuertz S. (2011). Improving qPCR Efficiency in Environmental Samples by Selective Removal of Humic Acids with DAX-8. Journal of Microbiological Methods. 85 (1), 16-21.

Report:

Schriewer, A., Bae, S., Rizvi, A., Sirikanchana, K., Wang, D. and Wuertz, S. (2009). Completion of environmental toolkit for fecal source tracking and pathogen analysis in stormwater. Report prepared for the Environmental Division of California Department of Transportation. Report #: CTSW-RT-09-168-23.2.

Microbial Source Tracking as Component of the Stockton Pathogen TMDL Characterization Study

Timeline: 2006-2008
Prime: Larry Walker & Associates
Study Location: City of Stockton: Mormon Slough, Smith Canal (Phase I)
Role: PM / Lab Manager

Background:

The federal Clean Water Act requires states to develop water cleanup plans for “impaired” rivers, lakes and streams. Impaired waters are those that do not meet water quality standards. Recent monitoring efforts have identified bacteria (pathogens) as an impairment to seven waterbodies within the Stockton Urbanized Area (this includes the City of Stockton and portions of San Joaquin County). In addition, the City and County (Permittees) received a National Pollutant Discharge Elimination System (NPDES) permit covering discharges from the storm drain system. The State Board has designated seven waterbodies within the Stockton Urbanized Area as being impaired by pathogens:
Mosher Slough , Five-Mile Slough, Lower Calaveras River, Smith Canal, Mormon Slough, Walker Slough, Deep Water Ship Channel.
Smith Canal, Five Mile Slough and the urbanized portion of Mormon Slough receive storm water runoff only from the Stockton Urbanized Area. In addition to storm water runoff from the Stockton Urbanized Area, Calaveras River, Mosher Slough, and Walker Slough receive storm water runoff from agricultural areas upstream of the Stockton Urbanized Area. In most areas of the Stockton Urbanized Area, dry weather flow and storm water runoff flow by gravity to pump stations where the flows are released to sloughs/rivers. The sloughs drain westerly into the San Joaquin River, which runs along the western side of the Stockton Urbanized Area. The quality and quantity of these discharges vary considerably and are affected by hydrology, geology, land use, season, and sequence and duration of hydrologic events.
The waterbodies in questions are protected for recreational uses, including boating, fishing, water skiing and swimming. The permit requires the Permittees to develop a Pathogen Monitoring Plan to address the bacteria within six of these waterbodies. The primary objectives of this Pathogen Monitoring Plan are to (1) identify the timing, extent, and magnitude of bacterial concentrations in six 303(d) listed waterbodies within the City of Stockton (City) by collecting dry and wet weather discharge and receiving water data, and (2) identifying the specific sources of bacterial pollution.
As part of phase I of the monitoring plan water quality samples were collected and analyzed for microbial source tracking markers and human pathogens by UC Davis at 8 stations in the City of Stockton at Mormon Slough and Smith Canal from 2006 to 2008. For the timeframe between October 2006 and September 2008 Dr. Alexander Schriewer has been in charge of phase I monitoring efforts for the Dr. Wuertz group.

Characterization of Road Runoff and Re-mobilization Potential of Particle-bound Heavy Metals

Timeline: 2003 – 2005
Funding Source: Oswald Schulze Foundation
Study Location: “Mittlerer Ring” (high capacity ring road in the center) in Munich and Laboratory of the Technical Supervisory Organization of the institute for Water Quality Control and Waste Management.
Role: Primary Researcher

Background:
The National Water Quality Inventory reports that runoff from urbanized areas is the leading source of water quality impairments to surveyed estuaries and the third-largest source of impairments to surveyed lakes (EPA 2003). Since road surfaces comprise the largest proportion of all impervious urban surfaces significant loads of pollutants originate from these surfaces such as nutrients, heavy metals and hydrocarbons (Ngabe et al., 2000; Davis et al., 2001; Farm, 2002). Their runoff is considered a major source of the pollution in the environment (Brezonik and Stadelmann, 2002; Lee et al., 2004). Under certain conditions, related to the nature and characteristics of the road, the runoff event and the receiving water body or ecosystem, pollutants in highway runoff may exert an acute or chronic impact on the receiving soil or water-based ecosystem (Opher et al., 2009). For example in urban receiving waters, the principal pollutants are suspended solids, heavy metals, hydrocarbons and de-icing salts (Mungur et al., 1995). Traffic characteristics (mean vehicle speed, traffic load, etc.), long dry weather periods, climate, rain intensity and rain duration are regarded as important factors in generating pollutions in road runoff (Lee et al., 2004; Crabtree et al., 2006). Therefore, the quality of urban runoff is of increasing concern to communities (Ball et al., 1998).
Unfortunately, significant differences concerning pollutant constituents in stormwater runoff have been found between studies carried out in different countries. The variability from one location to another caused by differences in land-use, climatic influences, traffic density, atmospheric deposition, maintenance, road drainage designs and vehicular traffic density indicates the need for local data (Marsalek et al., 1999; Brezonik and Stadelmann, 2002). Study areas comprise locations in Australia and New Zealand (Ball et al., 1998; Drapper et al., 2000; Mosley and Peake, 2001; Brown and Peake, 2006), North America (Sansalone et al., 1996; Brezonik and Stadelmann, 2002; Lee et al., 2004), Asia (Lee et al., 2002) and Europe (Farm, 2002; Westerlund et al., 2003; Gnecco et al., 2005; Mangani et al., 2005). However, specific data on urban road runoff for Germany are scarce.
On-site treatment plants for elimination of polluted runoff are under consideration and a part of best management practices (BMPs) to replace existing combined or separated sewer systems

(Nanbakhsh et al., 2007). For the development of effective treatment systems knowledge about the occurrence of metals and their attribution to the dissolved or particulate phase is crucial (Sansalone et al., 1996). Many already used treatment systems (geo-textile bags, slow sand filters, etc.) rely on the retention of particulate matter, which is, however, not removed from the runoff flow but remains as passive filter in the systems. A change in runoff composition like e.g. an increase of ionic strength of the runoff due to de-icing salt or a significant pH change within the filter cake due to biological degradation of organic compounds application has the potential of remobilizing these accumulated pollutants at once and thus posing a higher risk than untreated runoff.
The aim of the project was to characterize water quality of heavily polluted urban road runoff for the development of BMPs for climate conditions of the most European countries. Therefore, the concentrations and speciation of the most common heavy metals (Zn, Cu, Pb, Ni, and Cd), organic carbons in general as well as PAHs specifically, de-icing salts, and standard water quality parameter have been analyzed and correlated with climatic and locational factors. Moreover the remobilization potential of heavy metals associated to the particulate portion has been assessed.

This project supported two Research Associates to combine engineering and chemical backgrounds. While his project partner Dr. Rita Hilliges focused on engineering aspects of treatment systems Dr. Schriewer was responsible for the analysis for PAHs, analysis of remobilization capacities for particulate heavy metals and design of laboratory experiments. The responsibility for the overall project management and monitoring schedule was shared by both.

Publications:

Helmreich B., Hilliges R., Schriewer A., Horn H. (2010). Runoff pollutants of a highly trafficked urban road – Correlation analysis and seasonal influences. Chemosphere (80) 991-997.

Schriewer A. (2006): Pollutants in urban storm water runoff and their impact on decentralized treatment systems. Original title (German) Schadstoffpotentiale urbaner Niederschlagsabläufe mit Hinblick auf Behandlungsmöglichkeiten in dezentralen Systemen, Berichte aus Wassergüte- und Abfallwirtschaft der Technischen Universität München“. No 191, Hieronymus Verlag. SSN 0942-914X.

Colloidal Transport of Contaminants During Rain Water Infiltration (KORESI)

Timeline: 2003 – 2006
Funding Source: German Research Foundation (DFG)
Study Location: Zinc roof on campus of the Technische Universität, Munich in Garching, Germany and laboratory experiments at the Institute of Water Quality Control and Waste Management.
Role: Primary Researcher

Background:
Rolled zinc and copper sheets are commonly used as roofing materials and for drainage systems in countries all over the world. The use of copper as a roofing material has a long tradition in Europe back to the 16th century when copper began to be used in Scandinavian countries, originally to prevent buildings from catching fire. Zinc sheet has been used as a roofing material for over two hundred years. Any metal exposed to atmospheric conditions is subjected to corrosion processes through which corrosion products are formed and accumulate on the surface of the metal roof. During a rain event a part of these products will remain on the surface (patina) and a part will be released and driven in the roof runoff. Traditionally the roof runoff is sent to sewers through which the rainwater is either directly transported to the receiving water or, in case of combined sewer systems, sent to waste water treatment facilities. On site infiltration of roof runoff as an alternative dewatering concept is under intensive discussion. The use of artificial porous media to eliminate the contaminant load of the roof runoff such as heavy metals, before the water enters the soil and the ground water includes a high risk. One of the most important factors affecting the performance of those infiltration facilities is the contaminant phase distribution, meaning particle, dissolved and colloidal phase.
Mobile colloids in aquatic systems can act as carriers for sorbing contaminants such as heavy metals and therefore may enhance contaminant transport. The colloidal transport through porous media such as aquifers and water supply wells is well documented. Mc Carthy and Degueldre (1993) have demonstrated that mobile colloids are mostly composed of clay minerals, oxides and hydroxides of Fe and Al, silica, carbonates, and/or natural organic matter (NOM). Manifold different origins for the solid and colloidal fraction in the roof runoff of metal roofs have been reported. According Wallinder et al. (2001) the roof material itself plays an important role on the heavy metal speciation in the roof runoff. By contrast Murakami et al., (2004) demonstrated that the roof orientation has a significant contribution on the origin of the solid and colloidal fraction in the roof runoff. The aim of this study was to define the phase distribution of the contaminants of a fourteen years old zinc roof runoff, regarding weather conditions, roof orientation and profile of the rain event and how this distribution could affect the performance of three different artificial porous media in respect to contaminant elimination.

Publications:

Schriewer A., Horn H., Helmreich B. (2008). Time focused measurements of roof runoff quality. Corrosion Science, (50) 2, 384-391.

Schriewer A., Athanasiadis K., Helmreich B. (2007): The Role of Colloid Transport in Metal Roof Runoff Treatment. Colloidal Transport in Porous Media. Springer Berlin, 273-286. ISBN: 978-3-540-71338-8.