Surface and Groundwater Cleanup – Aluminum Aquatic Toxicity
Florida has established default surface water cleanup target levels (SWCTLs), which apply to surface water and groundwater impacting a nearby surface water body. The default SWCTLs for many chemicals are lower than the groundwater cleanup target levels (GCTLs) and, in some cases, even lower than background conditions. Meeting these cleanup endpoints can be technically challenging, time-consuming, and sometimes cost-prohibitive. Today’s technical blog highlights achieving aquatic protection more sustainably and economically.
Such is the case for aluminum. The default freshwater SWCTL for aluminum is 13 µg/L, lower than the GCTL (200 µg/L) and typical background levels (31-2790 ug/L, Miami-Dade County 2022). This SWCTL, which aims to protect aquatic life from chronic toxicity, was calculated by the University of Florida in the early 2000’s (Technical Report, FDEP 2005). Fortunately, the United States Environmental Protection Agency (US EPA) has since enhanced how we evaluate aluminum toxicity to aquatic life, reflecting the latest scientific knowledge and resulting in a more practical cleanup standard.
US Environmental Protection Agency Water Quality Criteria for Aluminum Aquatic Toxicity
In December 2018, USEPA released the Final Aquatic Life Ambient Water Quality Criteria for Aluminum 2018 (USEPA, 2018). This document outlines an approach to calculate site-specific acute and chronic freshwater aluminum thresholds. Similar to the default SWCTL, the USEPA approach considers the most sensitive relevant species and the median lethal concentration (LC50) of aluminum for that species. However, the USEPA approach also accounts for variations in site-specific water chemistry, including pH, dissolved organic carbon (DOC), and total hardness, which are known to influence aluminum bioavailability, as follows:
Multiple linear regression (MLR) models were developed to characterize the bioavailability of aluminum in aquatic systems based on the effects of pH, DOC, and total hardness on aluminum toxicity. In addition, the agency created a user-friendly Aluminum Criteria Calculator (Aluminum Criteria Calculator V.2.0.xlsm) that allows users to enter site-specific values for pH, DOC, and total hardness to calculate the appropriate recommended freshwater acute and chronic criteria for site-specific parameters. In summary, the calculator uses the LC50, but normalizes it using the site-specific pH, DOC, and total hardness. In addition, the USEPA 2018 document includes tables with the recommended criteria for various water chemistry conditions.
Note that the USEPA 2018 document also outlines the MLR models and the calculator’s pH, DOC, and total hardness bounds as follows:
Case Study – Aluminum Aquatic Toxicity and a Residential Development Site
SCS Engineers is currently assessing a site under development for residential use. The site has an existing on-site lake, which historically has received unknown fill. Surface water sampling results confirmed aluminum concentrations (31.2 µg/L – 219 µg/L) in excess of the default SWCTL (13 µg/L). The regulatory agency has requested additional assessment and monitoring based on the sampling results and site conditions. Given the time and cost of this approach and the uncertainty in a defined path to closure, SCS instead opted to derive an alternative SWCTL (ASWCTL) using the USEPA approach.
Using the Aluminum Criteria Calculator V.2.0 (US EPA 2018) and site-specific water chemistry data from the site, SCS calculated acute (criterion maximum concentration, CMC) and chronic (criterion continuous concentration, CCC) criteria. The acute criterion protects 95% of the species in a representative aquatic community from the acute effects of aluminum. The chronic criterion represents the maximum concentration of aluminum, protecting most aquatic organisms from unacceptable short or long-term effects.
We calculated site-specific CMC and CCC values using site-specific pH, DOC, and total hardness. Site-specific pH (6.83 – 8.39) and total hardness (151 mg/L – 204 mg/L) fell within the MLR model and the calculator bounds. DOC (3.4 mg/L – 28.2 mg/L), however, did not. Although two site DOC concentrations (14 mg/L and 28 mg/L) exceeded the MLR models and calculator upper bound, we used the maximum allowable DOC concentration of 12.0 mg/L in the calculator. This approach is conservative since lower DOC concentrations result in higher bioavailability and, in turn, increased toxicity.
After evaluating the calculated CMC and CCC for each scenario, we selected the chronic criterion of 550 µg/L to serve as the ASWCTL. Using this ASWCTL, SCS recommended no further assessment or monitoring for the on-site lake. This more sustainable solution will help our client meet construction schedules, reduce costs, and expedite site closure while meeting surface mandates.
About our Authors: Meet Anabel Rodriguez Garcia and Lisa Smith
References and Resources:
Aluminum Criteria Calculator V.2.0 (USEPA 2018) https://www.epa.gov/wqc/2018-final-aquatic-life-criteria-aluminum-freshwater
Technical Report, FDEP 2005: Development of Cleanup Target Levels (CTLs) for Chapter 62-777, Florida Administrative Code. February 2005, prepared by the Center for Environmental & Human Toxicology, University of Florida.
Miami-Dade County 2022. Background Concentrations of Metals in Groundwater – Miami-Dade County. August 11, 2022. https://www.miamidade.gov/environment/library/reports/2022-08-11-background-concentrations-of-metals-in-groundwater.pdf
USEPA 2018. Final Aquatic Life Ambient Water Quality Criteria for Aluminum 2018. EPA/822/R-18/001. December 2018 https://www.epa.gov/sites/default/files/2018-12/documents/aluminum-final-national-recommended-awqc.pdf
Brownfields, Remediation, and Land Recycling
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The Composting Consortium, an industry collaboration managed by Closed Loop Partners’ Center for the Circular Economy, released new resources that Greg McCarron of SCS Engineers recommends to municipalities looking to start or enhance a composting program. A blueprint, “How Organics Diversion Can Help Achieve Zero Waste Goals,” offers a clear and actionable framework, including:
Policy and Program Expansion for Diverting Food Waste: This section dives deeply into effective strategies for policy development. It explores methods to incentivize resident and business participation while outlining pathways to maximize food waste diversion from landfills.
Setting Up Programs and Infrastructure: This section provides a clear roadmap for establishing new organics programs. It details best practices for collection methods, explores various processing options (composting facilities, anaerobic digestion), and offers guidance on navigating the critical process of contracting with composters.
Communication with Program Participants: This section provides a comprehensive communications toolkit. It outlines strategies for educating participants on proper sorting techniques, maximizing program participation, and fostering long-term program success.
The site also includes platforms and programs that you may find useful and help connect you with other city officials and leaders nationwide to share and discuss best practices in starting and expanding organics programs & composting infrastructure.
These free, non-commercial resources will help you appreciate and understand applying the science and practice of composting and what is critical to a successful site, design, permit, and manage municipal composting programs that support circularity and operational efficiencies – creating value for all stakeholders. Many municipalities are interested in growing their programs to help the environment and provide a useful byproduct by reducing the amount of waste being hauled away and ultimately placed in landfills.
More Composting Educational Resources:
Municipalities, regions, and private companies are turning to organic composting to divert organic wastes from landfills and reuse them as feedstock for a high-quality compost by-product. While theoretically simple, there is a logical series of processes and parameters, some specific to each site, to reach the goals communities and solid waste management organizations hope to achieve.
Whether your community or region already has composting and is scaling to include food waste, or you want to establish a new composting facility or regional composting site, these free educational resources can help. The Southeastern Connecticut Regional Resources Recovery Authority’s proposed compost facility reflects a well-thought-out strategy that leverages circularity, advanced composting technologies, and engineering best practices to create a sustainable and economically viable operation.
SCRRRA’s Executive Director, David Aldridge, walks us through his proposed regional compost facility, which reflects a well-thought-out strategy that leverages advanced composting technologies and engineering practices to create a sustainable and economically viable operation. Greg McCarron, Professional Engineer, and Certified Compost Professional, discusses hybrid systems and incorporating rigorous process controls, resulting in a forward-thinking approach to composting at scale.
These free, non-commercial resources will help you appreciate and understand applying the science and practice of composting and what is critical to a successful site, design, permit, and manage composting programs that support circularity and operational efficiencies – creating value for all stakeholders.
The Grand Slam of Composting Educational Resources:
Helpful Composting Program Resources:
On July 16, 2024, the Volusia County Council approved a contract with SCS Engineers to develop a new 271-acre Class I landfill. The landfill, located at the southeast expansion area (SEA) of the Tomoka Farms Road Landfill, is part of the County’s long-term plan to meet its Class I sanitary solid waste disposal needs for over a century. The Public Works will oversee the project, Solid Waste Division, under the guidance of the County’s Project Manager.
SCS Engineers will provide a range of engineering services, including developing a solid waste permit application package for the Florida Department of Environmental Protection. They will design the landfill gas collection and capture system, supporting infrastructure, geotechnical needs, and leachate collection to protect groundwater and soil. Additionally, they will provide support services for selecting a construction contractor for the first 20-acre disposal cell at the new landfill.
SCS will collaborate with the County to identify any constraints that may impact the cost or constructability of future projects. They will also explore potential opportunities associated with this project to ensure the design complements and maximizes future development opportunities.
Landfills are complex systems integrating liquid and gas management systems to protect the environment. Volusia County selected SCS Engineers for their expertise in designing modern landfills that adhere to strict state and federal regulatory and quality control guidelines. The firm’s understanding of how current landfill operations interrelate with the development of SEA was a key factor in their selection.
Modern landfills are ecosystems that isolate waste from surrounding environments, such as groundwater, air, and rain. While the County’s reuse, recycling, and organics management programs significantly reduce waste in landfills, the SEA development provides an essential service that will continue uninterrupted as communities transition to even more sustainable programs and infrastructure to reuse landfill gas and other byproducts.
Vice President Dan Cooper, P.E., expressed his gratitude, stating, “SCS is privileged that Volusia County has entrusted us as a partner to sustainably engineer SEA’s safe and efficient development. We’re honored to assist the Solid Waste Division in their mission to support the citizens and the environment.”
Additional Resources:
Join your fellow SCS Engineers at the Organics Waste Management Summit 2024 in Bordentown, New Jersey. With an exciting theme of “Composting & Beyond!”, this event hosts a large audience of organics processors, composters, haulers, regulators, academics, organics waste management, professionals, and more. This year’s agenda includes panels and breakout sessions discussing topics like a Macro Look at Market Challenges, Partnerships for Successful Programs, Organics Policy and Regulation, and Compost Technologies. A continental breakfast, lunch, and networking are all complimentary bonuses for your attendance.
Take advantage of this insightful opportunity to learn and grow at the Organics Waste Management Summit 2024. Register now!
The Virginia Waste Industries Association is teaming up with the NWRA Carolinas Chapter to host the Annual 2024 Mid-Atlantic Conference & Golf Tournament at the Omni Homestead Resort in Hot Springs, Virginia. This event will be an enriching experience filled with discussions on the latest trends and challenges in the waste and recycling sector. In addition to the insightful discussions and networking opportunities, this year’s event features the highly anticipated “Pitchers and Putters” Tim Torrez Classic Golf Tournament.
Join fellow waste and recycling industry professionals for an action-packed week and register for the NWRA Mid-Atlantic Conference and Golf Tournament today!
The Southwest Virginia Solid Waste Management Association (SVSWMA) is hosting the 40th Annual Conference at the Mountain Lake Lodge in Pembroke, Virginia. Register to have the “Time of Your Life” with three full days of networking and discussing topics like solid waste regulations, recycling, operator training, and more. The agenda for the event features a golf tournament, skeet shooting activities, and a Vendor and Welcome Reception on Monday September 16th, and work sessions and tours on Tuesday and Wednesday.
Be a part of the action and have the “Time of Your Life” at the 2024 SVSWMA Annual Conference! Register today!
Join SCS Engineers at the 2024 SWANA North Carolina Chapter Fall Conference in Wilmington, North Carolina. The agenda for this event is robust with programming including a tour of the new Hanover Landfill, sessions on a range of the most prevalent topics in solid waste, young professional events, Garby award presentations, and ample networking opportunities. Seize this opportunity to spend a week with your fellow SWANA colleagues to increase your understanding of the industry and stay informed on the latest developments.
Act now and take advantage of early registration discounts and room blocks. Register for the NC SWANA 2024 Fall Conference today!
The Association for Environmental Health and Soils (AEHS) is hosting the 40th Annual International (East Coast) Conference on Soils, Sediments, Water, and Energy in Amherst, Massachusetts, October 21-24, 2024. The AEHS conference attracts participants from government agencies, environmental engineering firms, consulting companies, industry, and academia and serves as a networking hub for various associations. The program features technical workshops, presentation sessions, and an exhibit hall. It also offers continuing education credits (please check with your specific board for applicability). SCS recommends attending this conference for its valuable insights and networking opportunities.
SCS Engineers and a Pennsylvania Department of Conservation and Natural Resources (DCNR) state geologist presented a webinar as part of the Pennsylvania Council of Professional Geologists (PCPG) educational series. The educational webinar is timely as Governor Josh Shapiro recently signed Senate Bill 831 into law, creating a regulatory framework for the Commonwealth’s carbon capture, utilization, and sequestration (CCUS).
The webinar, titled CCUS in the US and a Glimpse into What is Possible in Pennsylvania, Part I, includes SCS geologists from across the nation providing a technical overview of CCUS project planning, permitting, operations, and closure referencing current, active Class VI projects based on case studies. The webinar is available for a nominal fee on PCPG’s website, and professional credits (PDH or CEU) are available as allowed by your licensing state and entity.
The DCNR’s state geologist provides an overview of the CCUS work in Pennsylvania by DCNR for over 20 years, including coordinating with the Department of Energy, other states’ geological surveys, and public-private organizations to explore CCUS in the Commonwealth and neighboring states.
Questions and Follow-Up
During the live webinar, SCS received multiple inquiries from the audience, similar to our clients’ questions. We’ve created a separate video to answer them, which is available on the SCS website at the bottom of the carbon capture and DWI page. We hope you find the videos informative and valuable. Our geologists are passionate about their work and helping clients navigate regulations and implement sustainable projects.
Pennsylvania Senate Bill 831 and Other States
Our professionals continue to work on Class VI projects with multiple clients across the US where primacy has been granted, or states have regulations in place, including the outlook for CCUS in Pennsylvania.
Pennsylvania Senate Bill 831 establishes the legal and regulatory framework for the Commonwealth’s potential carbon dioxide capture, utilization, and sequestration (CCUS). SB831 provides “for the injection of carbon dioxide into an underground reservoir for the purpose of carbon sequestration, for the ownership of pore space in strata below surface lands and waters of the Commonwealth, for conveyance of the surface ownership of real property; imposing duties on the Department of Environmental Protection and the Environmental Hearing Board; and establishing the Carbon Dioxide Storage Facility Fund.”
View a copy of the Bill here: https://www.legis.state.pa.us/cfdocs/billinfo/billinfo.cfm?sYear=2023&sInd=0&body=S&type=B&bn=0831.
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