We know that research is one of the things our members most want Northwest Biosolids to prioritize! This round-up for 2020-21 gathers the past year’s infamous Resource Libraries in one place, captures learning events and the valuable research conducted during the 2020/21 research cycle. Your membership dues helped to fund all of this and more.

Resource Libraries Each month, Dr. Sally Brown provides a review of five research publications in a themed area and helps our members make sense of it all.

July 2020 More Microplastics – Like everything else, they end up in wastewater and your laundry is a primary source

Aug 2020 NPDES – Focus on macro issues: NPDES permit compliance (evaluation of different technologies and considering resource recovery potential)

Sep 2020 COVID-19: Part 3 -There is even more evidence that fecal transmission is not a major pathway and that wastewater treatment and its products are not a real concern for transmission

Oct 2020 Fire – Fire’s impact on soils and how biosolids and compost can fit in to limit the damage

Nov 2020 More PFAS – Review of 2020 publications to broaden the understanding of PFAS in the environment, the role of biosolids and composts and a what to do about it

Dec 2020/Jan 2021 Protect Your Turf – Lawns can have an environmental upside, one that biosolids and compost make better

Feb 2021 Safe to Swim? – Health risks associated with swimming in waters with potential contamination resulting from aging sewage pipes, CSOs and stormwater

Mar 2021 Carbon Models – Soil health to fight climate change; a look to see how biosolids is recognized by people who don’t work directly with ‘cake’

Apr 2021 Biosolids Based Biochar– A review of how biosolids biochar can be used as a soil amendment reveals there’s limited research and suggests biochar has no clear advantage over cake

May 2021 How Organics Can Help Fight Against Soil Borne Pathogens; and PFAS – Still in the News – Putting PFAS in biosolids into perspective

Jun 2021 More PFAS – This Time in Your Cosmetic Bag – More perspective coinciding with Sierra Club’s publication on toxic sludge and PFAS

Events – Member Access Only (Please login to the Information Portal on the website before viewing)

June 2020- Understanding Risk Assessment – How to Utilize Risk Assessment for Biosolids (recording) Dr. Sally Brown, University of Washington led 2 class series: basics of risk assessment & how to use risk assessment in biosolids programs.

Sep 2020- Community Outreach & Education Toolkit (recording) Featured speaker Siena Ezekiel, Education & Outreach Specialist, King County (WA). Numerous resources are provided in this webinar toolkit.

Dec 2020- Biosolids 101 (recording) Crash course featuring seasoned professionals, each with over 25 years direct biosolids experience, from across sectors specializing in regulations, research, and program management. Featured speakers: Andy Bary, Soil Scientist WSU; Sally Brown, WSU; Kyle Dorsey, WA State Department of Ecology; and Dan Thompson, City of Tacoma-TAGRO.

Jan 2021- NW Biosolids 201 – (recording) Overview of key biosolids research projects and findings that range from crop response to risk analyses. Sally Brown (UW) and Andy Bary and Deirdre Griffin-LaHue (WSU) share what biosolids research has unveiled over the past 30 years.

Jan – Feb 2021- Soils 101Six-part classroom series with Dr. Sally Brown was delivered to Cohort 1. Course syllabus: Biosolids are applied to soils at rates to meet the fertilizer demands of crops. To really understand what all the fuss is about – both good and bad, it helps to have a basic understanding of soils and soil processes.

Research Study Outcomes

Urban agriculture/food quality – Dr. Sally Brown, University of Washington
This King County-NWB co-funded study is nearing completion with the final manuscript in-progress! The study focused on urban soil, or soils near urban areas. The study also included a greenhouse trial component. A range of soil amendments including two biosolids products, vermicompost, Bokashi, and compost tea were tested for their impact on soil health. For high quality urban soils, the biosolids amendments are generally similar to fertilizer addition for plant yield. However, using amendments instead of fertilizers improves multiple soil properties including total C and N, water infiltration rate, and bulk density. Nutrient availability is also generally increased. The research results suggest that amendments including vermicompost and biosolids compost and topsoil blends can be much more effective in restoring soil health and plant yield to low quality urban soils. Anne Beebe, a MS student working on a component of this study, defended her research in July 2021. The manuscript synthesizes the soil and plant data from the greenhouse and field trials.

Forest carbon sequestration – Dr. Sally Brown, University of Washington
This is a study that was initiated in 2018 by King County with additional funding provided by NWB starting in 2019. Peer review literature suggests that forest applications improve soil quality and increase tree biomass – much of this literature has come from New Zealand. Forest applications are a viable market for many NWB members. Understanding carbon storage for forest applications can be used for municipalities that apply biosolids to forestry for internal carbon accounting. Understanding tree response can be used to quantify the value of biosolids applications to forests – a useful tool in negotiations with forestry companies and contract managers for application sites and to expand or develop new project sites. Soil and tree sampling at long-term, controlled sites on WA’s Department of Natural Resources land as well as commercial applications provides quantitative data for the Pacific NW on tree and soil response to agronomic biosolids application rates. You can read more about this project in Biosolids Forestry & Carbon . A publication is currently in-press in the Journal of Environmental Management based on this research.

Biosolids as a Tool to Improve Soil Health – Soil Health Institute project, Dr. Deirdre LaHue, Washington State University
In 2019, the long-term biosolids research site “GP-17” located in eastern WA was selected to participate in an international study evaluating soil health across North America (United States, Canada and Mexico). The study compares research sites that have been managed uniformly over a long period of time. GP-17 is being compared to other conventionally managed sites using different treatments crop rotation, compost and manure addition, and cover cropping etc. There are over 120 different research sites participating in this study, including one other biosolids site located in Colorado. Major findings demonstrate that long-term biosolids applications have substantially improved physical, chemical, and biological soil properties. Available water holding capacity in the soil is crucial in this low rainfall region with dryland (non-irrigated) agriculture. A manuscript for publication for the GP-17 site was started in June 2021 and the publication will mark the end of this project (2022). However, it will be important to continue monitoring soil health properties over time as this is an important area of research and long-term studies are rare. You can read more about this project in Impacts of Biosolids on Soil Health: Updates from the Soil Health Institute’s project and you can listen in on Biofest Sept 16, 21: Wellness 1 – Soil Health 101 by Griffin LaHue, Bary and Desjardins – YouTube where Dr. LaHue also talks about the Soil Health Institute project.

Accumulation of microplastic and nano particles from biosolids in agricultural soils, Dr. Markus Flury, Washington State University
This is an ongoing study led by Dr. Markus Flury with major funding coming from the USDA National Institute of Food & Agriculture. While there is a wealth of information available about microplastics in aquatic ecosystems, there is very little known about microplastics in terrestrial ecosystems. In 2020 and 2021, soil samples from the long-term biosolids research site GP-17 (Douglas County, WA) were collected to analyze for silver and microplastic concentrations. Silver was included in the study because it is easier to analyze than microplastics (allowed determination of how accurate we can measure a mass balance of silver applied by biosolids and silver measured in soil). The silver concentrations in the biosolids-amended soil increased steadily from 1996 until 2007, after which the concentrations leveled off at 1.25 mg silver/kg. The observed silver concentration is below estimated ecotoxicity limits for silver nanoparticles in soil. New sampling protocols were also developed to improve soil sampling for quantification of microplastics in soil. You can read more about this project in Silver from biosolids accumulates in soil, but overall silver concentrations remain low even after long-term biosolids application – Silver analyses may be used to quantify microplastics in soil and publications:

Taylor, S.E., Pearce, C.I., Sanguinet, K.A., Hu, D., Chrisler, W.B., Kim, Y.M., Wang, Z., Flury, M. 2020. Polystyrene nano- and microplastic accumulation at Arabidopsis and wheat root cap cells, but no evidence for uptake into roots. Environ. Sci. Nano 7, 1942-1953. https://doi.org/10.1039/d0en00309c

Taylor, S. E., C. I. Pearce, I. Chowdhury, L. Kovarik, S. Baum, A. I. Bary, and M. Flury. 2020. Long-term accumulation, vertical distribution, and speciation of silver nanoparticles in biosolids-amended soils. J. Environ. Qual., 49, 1679-1689. https://doi.org/10.1002/jeq2.20156

Yu, Y., and M. Flury. 2021. How to take representative samples to quantify microplastic particles in soil? Sci. Total Environ., 748, 147166. https://doi.org/10.1016/j.scitotenv.2021.147166

Effects of biosolids on food webs in northern rangelands, Dr. Karen Hodges, University British Columbian-Okanagan
Previous research where biosolids have been applied at OK Ranch in British Columbia has shown that the soil health and grass productivity improved substantially. However, questions about potential impacts of biosolids on wildlife had not yet been answered. In 2016, Dr. Hodges and her team with support from SYLVIS, Metro Vancouver, National Sciences & Engineering Research Council of Canada, Upland Bird Society, Nature Trust, and UBC started to tackle this question. Over four summers, researchers examined grouse and songbird populations and their behavior, as well as raptors’ nesting patterns. They also measured grasshopper and vole populations that are the main prey species (food sources) for all these birds. Starting in 2020, NWB contributed funding towards the research program. This funding helped to support the last season of field and corresponding lab work and peer-reviewed publications. You can read more about the body of research Wildlife Responses to Terrestrial Grassland Application of Biosolids and you can listen in on Biofest Sept 21, 2021: Wildlife Research at OK Ranch – YouTube and www.metrovancouver.org/media-room/video-gallery/liquid-waste/500556099

The following publication came out during this cycle and three additional manuscripts are nearing completion. Publications will help to paint the picture of ecosystem foodwebs and a more complex analysis of wildlife response to biosolids and interactions amongst species.

Ormrod, A., F.I. Doyle, K.J. Lawson, and K.E. Hodges. 2021. Niche partitioning of avian predators in northern

grasslands amended by biosolids. Ecology and Evolution11:6248-6259. https://doi.org/10.1002/ece3.7461

Arizona Water & Energy Sustainable Technology Center (WEST Center), Dr. Ian Pepper
Though King County’s membership with the WEST Center, NWB coordination with the County captures and shares relevant information with our membership: Wastewater-Based Epidemiology for Averting COVID-19 Outbreaks on the University of Arizona Campus (Oct 2020 research short story)

Wastewater-based epidemiology (WBE) helped avert an outbreak of COVID-19 on Campus, and the news resulted in a frenzy of media activity, including broadcasts on CNN, NPR, ABC, NBC, and CBS; dozens of newspaper reports and articles in “The Atlantic” and “Politico.” Since the report of this Case Study was announced, numerous universities in the U.S. and abroad implemented WBE for monitoring student dorms.

PFAS in Biosolids: A Southern Arizona Case Study (Feb 2021 research short story)
This study took a broad look at PFAS contamination, retention, and migration in farm soils where biosolids were historically land applied. The data presented demonstrates very low concentrations of PFAS compounds in soils receiving biosolids with migration attenuated in the first few feet of soil. The concentrations are lower than published health-based screening criteria published by the USEPA. The low concentrations of PFAS in biosolids coupled with depth to groundwater of 150 to 400 feet and Arizona’s low rainfall helps minimize the impact on public health and groundwater. Here is the report PFAS in Biosolids: A Southern Arizona Case Study and peer-review publication:

Pepper, I.L., Brusseau, M.L., Prevatt, F.J., Barbara, A., Escobar. 2021. Incidence of PFAS in soil following long-term

application of Class B biosolids: A Southern Arizona Case Study. Sci. Tot. Environ.