Toronto

6ppd and 6ppd-Q, Environmental Fate and Transport and Current Regulatory Environment

Terrapex’s presentation will build on the overview of N‑(1,3‑dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) and its oxidation product, 6PPD-quinone (6PPD-q) proposed to be presented by SGS “6-PPD Quinone: Occurrence and Best Practices in Measurement”.

These compounds, which have been determined to be severely toxic to Coho salmon and other species, are known to be entering waterways from runoff containing tire wear particles.  Research is in the very early stages but is progressing rapidly.  The presentation will focus on what will be of most interest to practitioners in site assessment and remediation and will present some of the challenges associated with these emerging contaminants.

The first segment of the presentation will review what is currently known about the physical and chemical properties of 6PPD and 6PPD-q and how these influence the environmental fate and transport of the compounds through water, soil, and air, as well as their potential for bioaccumulation and toxic effects.  The second segment will review the current regulatory landscape surrounding 6PPD and 6PPD-q.  We will look at actions that have been taken or are being considered in various jurisdictions, including Canada, the USA and Europe, to monitor and/or control the use and release of these compounds. Additionally, the presentation will discuss the concerns, responses and initiatives of rubber product manufacturers and industry associations.

6-Ppd Quinone: Occurrence and Best Practices in Measurement

N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) is added to almost every automobile tire to prevent cracking from ozone. However, a newly discovered environmental reaction by-product 6-PPD-quinone (6-PPDQ) has been identified in 2020 as being responsible for urban runoff mortality syndrome (URMS) in Coho Salmon (Oncorhynchus kisutch). The LC-50 of 6-PPDQ is 41 ng/L to juvenile Coho making it one of the most toxic substances known to us. In addition to extreme toxicity in Coho, significant lethal effects (LC-50 1 µg/L or less) have been observed in geographically widespread species such as brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss). Toxicity shows 5 orders of magnitude species dependence.  Worldwide monitoring results show almost ubiquitous presence. Other sources of 6-PPDQ could be the reuse of tires in playgrounds and artificial turf near sensitive streams, and adjacent to factories manufacturing or using 6-PPD.

In this study, we

• Present recent advances in the measurement of 6-PPD and 6-PPDQ
• Collate and discuss Canada and world-wide occurrence of 6-PPDQ
• Shed light on tire and road wear particles (TRWP) and associated chemical constituents

This presentation will be followed by one from Terrapex on “6PPD and 6PPD-Q, Environmental Fate and Transport and Current Regulatory Environment”.

We developed and validated an isotope-dilution UPLC-MS/MS method in aqueous samples capable of measuring 6-PPDQ at concentrations 400 times below the LC-50. This work also revealed significant challenges in the measurement of the parent 6-PPD due to its significant instability.  Internal data on occurrence from coastal British Columbia and adjacent regions showed that 94% and 88% of the aqueous samples showed detected levels of 6PPD-quinone, and 6PPD respectively. The measured concentrations ranged from 0-740 ng/L for 6PPD-quinone and 0-5100 ng/L for 6PPD. On average, the concentration of 6PPD was 3.5x that of the 6PPD. The highest concentrations were detected in the wet season, and the lowest concentrations were detected in the dry season. Our method validation and initial occurrence data, and work of others in North America shows the widespread occurrence of 6PPDQ at levels toxic to multiple species. It also points to increased need for the monitoring of 6PPDQ, and the measurement of toxicity in other species given the wide variance in toxicity by species. In addition, there is emerging need to consider the regulation of 6-PPDQ in road runoff and to understand best practices for mitigation.

Chlorinated Solvent Daughter Product Management and Expedited Remediation

Chlorinated solvent degradation products, also known as daughter products, are generated at most remediation sites where an electron donor is introduced or where sufficient natural organic carbon is present in the aquifer. For sites where either perchloroethylene (PCE) or trichloroethylene (TCE) is the parent compound, the degradation products are primarily cis-1,2-dichloroethylene (DCE) and/or vinyl chloride (VC). Where source areas exist (e.g. mg/L concentrations of parent compounds), significant daughter product concentrations can be generated and can persist for extended periods of time, even decades.

This presentation will review project sites where activated carbon impregnated with metallic iron, a complex carbohydrate, a facultative microbial consortium designed to degrade chlorinated solvents, and a second microbial consortia designed to breakdown the polymeric carbohydrate to monomeric fragments were mixed and applied via in situ injection. This synergistic combination has been shown to generate significantly less daughter products and to degrade parent and daughter products completely to ethylene in an expedited timeframe compared to traditional enhanced reductive dechlorination (ERD) approaches.

Site 1. A combined remedial strategy was implemented to treat elevated levels of TCE in a shallow fine-grained aquifer at a former large industrial facility. This remediation effort was comprised of 1) in situ chemical oxidation to treat the shallow, mostly unsaturated soil mass, 2) a metallic iron-impregnated activated carbon PRB was installed downgradient of the source to manage the flux of dissolved mass offsite, and 3) the source area was treated with the above-mentioned combination of technologies and microbial consortia. Within the source area, total chlorinated ethylene (TCE+DCE+VC) concentrations in the source area have been reduced by 99.9% in less than three years. The initial TCE concentration was 47,800 ppb and is currently 2 ppb. DCE and VC concentrations peaked approximately six months post application and have since declined to 21 ppb and 9.4 ppb, respectively.

Site 2. A multi-year phased approach was utilized to remediate a comingled plume at a former chemical plant that stored, repackaged, and distributed a multitude of chemicals, including hydrogen peroxide, methylisobutyl carbinol (MIBC), PCE, acetone, ethanol, and diesel fuel. The first phase was a combination of ex situ and in situ remediation methods that were selected to achieve the site clean-up goals in specific plume areas of immediate concern. The initial total chlorinated ethylene (PCE+TCE+DCE+VC) concentrations were over 213,000 ppb with much of the mass as DCE (72%). After one-and-a-half years of source area treatment, the total concentration was 354 ppb with 25% being DCE and the balance as VC. After demonstrating over nine years of mass flux control with a PRB, and significant groundwater mass reductions in the source area, managed closure status has been requested by the consultant and is pending approval from the regulatory agency.

Hazardous Is The New Clean – Contaminate Management Supported Redevelopment

Pinchin will present a case study on a Contaminant Management Strategy that is currently being implemented on a brownfield in the GTA. Chlorinated solvents, petroleum hydrocarbons, potential off-Site migration and free product – the Site has a varied and storied past, complete with several ultimately unsuccessful remedial efforts and the well intentioned but unfortunately mismanaged handling of hazardous levels of PCBs. However, through the implementation of a robust property boundary control, hotspot remediation and isolation, and vapour intrusion mitigation and management, Pinchin is helping our Client take this diamond in the rough and polish it into a safe and economically viable asset

Soil Management Technology at the Toronto Portlands

The construction of the Toronto Port Lands Flood Protection and Enabling Infrastructure Project (Toronto Port Lands Project) is taking place in parallel with the introduction of environmental regulations that enforce the tracking of soil leaving the site.

At the Toronto Port Lands, not only are soils leaving the site tracked, but due to several reuse applications at the site, all soils being reused require tracking, which has led to the creation of new technologies to reuse the majority of the 1 million cubic meters of soil being managed.

New technologies like 3-D digital models, GPS driven machine control and remote sensing, cloud-based truck tracking, environmental and geotechnical analytical data management and a QP approvals platform work together to form a sophisticated, integrated tracking system.

As we all know, new technologies go a long way in simplifying work and optimizing outputs, however they come with their own set of challenges.

This presentation describes the new-age soil management technologies QM now implements at sites across Canada, initiated by work at the Toronto Port Lands project.

Ontario Excess Soils Management Panel Discussion

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Ontario Excess Soils Management Panel Discussion

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Ontario Excess Soils Management Panel Discussion

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Ontario Excess Soils Management Panel Discussion

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Don’t "Scrap" Your PRB – How to Optimize Treatment and Reduce Cost For Chlorinated Contaminant Destruction

Permeable reactive barriers (PRBs) composed of zero valent iron (ZVI) media have been widely applied for removal of chlorinated volatile organic carbon (cVOCs) from groundwater for past 30 years. Traditionally, PRBs have been designed and constructed based on the total mass of ZVI media applied without much consideration for permeability and porosity.

With experience, people have started to put attention to the quality of the material utilized and more recently the use of sponge-iron based media can offer significant performance and cost improvements versus traditional designs using regrind or atomized iron.

To investigate the potential benefits of alternative designs, column studies were conducted to explore the performance of a sponge ZVI media when used in a ‘typical’ PRB design. The laboratory column test consist of the novel sponge ZVI media, a conventional non-sponge ZVI media and a control was set up for benchmarking purpose. The study was conducted for two months using site groundwater contaminated with c-VOCs from a confidential site in the eastern USA. Aqueous concentrations of c- VOC were monitored along the column length to evaluate their degradation kinetics.

Results obtained concluded that, compared to the conventional ZVI media, the sponge iron media requires up to 30% less material (by weight) to achieve the same volumetric fill requirements. The results of the study also confirmed that sponge-iron based ZVI media showed similar or better c-VOCs removal with lower mass. This can offer significant cost advantages in real-world applications.

The lab and full scale application of this technology will also be presented and discussed.

Activated Carbon Solutions For PFAS Removal & Destruction

Per and polyfluoroalkyl (PFAS) compounds are a class of chemicals and are increasingly becoming environmental contaminants of concern. Much progress has been made in the development of various treatment strategies to remove PFAS from water, especially with sorbents and membranes. Of these, granular activated carbon (GAC) is one of the most widely deployed and well-established PFAS removal technologies.

This presentation will provide an overview of the use of GAC in PFAS removal applications, what factors impact the performance of GAC, and will provide typical system operation information. It will provide best practices on choosing a GAC and provide case study data on real GAC systems for PFAS removal.

Additionally, the presentation will provide information on carbon reactivation as a destruction process for PFAS. Carbon reactivation is thermal treatment at high temperatures, up to 1800°F, to remove and destroy adsorbed contaminants. The process is designed to return the carbon to a virgin-like state for reuse and ensure no contaminants remain on the carbon. During reactivation, the high temperatures employed in both the furnace and the downstream abatement system will volatilize and destroy organic compounds that were adsorbed on the GAC. The presentation will detail a study describing a stack testing campaign carried out at a commercial carbon reactivation facility in which the incoming GAC and all outputs including stack gas, abatement dust, and reactivated carbon were tested for fluoride and PFAS to determine the level of PFAS destruction. In the reactivation study, we analyzed non-detect for all measurable PFAS on the reactivated carbon, indicating that PFAS is effectively removed from the spent carbon during CCC’s proprietary reactivation process. We also demonstrated > 99.99% destruction for total PFAS (36 PFAS list measurable) across the furnace and abatement systems. We’ve demonstrated > 99.999% destruction for PFAS currently listed in the US EPA’s Drinking Water Health Advisory Limits (PFOA, PFOS, GenX, and PFBS) across our process and abatement systems

Snakes and Turtles And Bats, Oh My! What Environmental Consultants Need to Know About Species at Risk

Both federal and provincial governments have species at risk legislation, intended to protect listed plants, animals, and their habitat. Such legislation imposes obligations on industry and landowners, and often in redevelopment projects, when listed species are encountered at a project site.

Join Willms & Shier Environmental Lawyers to learn more about these obligations and how to spot key issues and assist your clients to navigate the federal Species at Risk Act and provincial species at risk legislation when undertaking remediation projects.

• This presentation will focus on key issues including:
• Requirements for landowners under federal and provincial legislation
• Permitting obligations
• Prosecution and fines, and
• Best practices for environmental consultants.

Vapor Intrusion Through Sewers: Sample Collection and Mitigation Methods

Evaluation of vapor transport through preferential pathways, including sewers, has been identified as a key component of vapour intrusion (VI) pathway assessments.  Many vapour intrusion guidance documents highlight the need to evaluate preferential pathways. Current research has highlighted the prevalence of preferential pathways and the need to evaluate vapour transport through sewers. Vapour transport through atypical pathways may transport volatile organic compound (VOC) vapours into buildings at a rate greater than would occur from diffusion through subsurface soils.  As such, preferential pathways can negate the use of evaluating risk with the Johnson and Ettinger Model or the use of vertical screening distances to exclude buildings at petroleum VI sites.

This presentation will provide a case study of the collection of samples from sewers using both passive and active sampling methods. The advantages and disadvantages of each of these methods will be discussed along with co-located comparison data. The presentation will highlight the investigation of a sewer line that contained VOC vapours and residential buildings downgradient of a contaminated site. Based on the findings of the preferential pathway assessment, mitigation measures, consisting of active sewer venting, were determined to be appropriate.  Overview of the design, installation and post monitoring results will be discussed.  Lessons learned though the investigation and implementation of the mitigation measures will be highlighted.

Money Talk: FCSAP Phase V Demand

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