Earth Day Mirror Lake Wetland Cleanup Commemorates Acclaimed 2013 DNREC Remediation and Restoration Project

Gov. Carney joined DNREC staff, city of Dover workers and volunteers from local business and organizations for an Earth Day cleanup at Mirror Lake in Dover, commemorating a precedent-setting environmental cleanup 10 years ago by DNREC that garnered national acclaim. /DNREC photo

 

Governor John Carney joined state and city employees ahead of Earth Day today to remove invasive plant species and dead vegetation at Mirror Lake in Dover. The event was organized by the Delaware Department of Natural Resources and Environmental Control and the city of Dover 10 years after a successful environmental cleanup and habitat restoration at the site was undertaken by DNREC’s Watershed Assessment and Management Section and WATAR (Watershed Approach to Toxics Assessment and Restoration) team.

The 2013 cleanup used an innovative carbon technology to sequester (bind) carcinogenic polychlorinated biphenyls (PCBs) and remove them from the ecosystem in Mirror Lake. The work helped to improve the natural beauty of the lake, increase the lake’s ecological function, and made the fish there safer for human consumption.

“The Mirror Lake restoration project was an opportunity for our community to come together to tackle important environmental and water quality concerns,” said Governor Carney. “I want to thank DNREC and the city of Dover’s continued efforts to monitor and improve the health of this beautiful lake.”

“What was accomplished at Mirror Lake, though smaller in scope, was monumental as a springboard for similar projects to be conducted by our WATAR team, and others across the nation, since 2013,” said DNREC Secretary Shawn M. Garvin. “I am proud in knowing that DNREC was an early adopter of this promising remedial technology, and that we now confidently use it in other areas of the state where appropriate to help us continue making gains with water quality and in restoring fish and wildlife habitat.”

Members of the Epsilon Iota Omega Chapter of Alpha Kappa Alpha Sorority, Inc., joined in the Earth Day cleanup and beautification for Mirror Lake in Dover with Gov. Carney, DNREC staff and city of Dover workers. /DNREC photo
Members of the Epsilon Iota Omega Chapter of Alpha Kappa Alpha Sorority, Inc., joined in the Earth Day cleanup and beautification for Mirror Lake in Dover with Gov. Carney, DNREC staff and city of Dover workers. /DNREC photo

Dover Mayor Robin R. Christiansen said, “Mirror Lake speaks to Dover’s civic pride. Over the last decade it has evolved into a beautiful event venue that includes private weddings. We are thankful for the partnership with DNREC and the state of Delaware in achieving it, while being able to maintain the beauty of Mirror Lake for the neighbors and our community.”

With Mirror Lake continuing to rebound from longtime environmental ills as it empties into the St. Jones River, the wetland now plays an important role in improving water quality in the St. Jones Watershed, which spans the southern half of Kent County and Delaware’s capital city, including nearby Legislative Hall and the Tatnall Building housing the Governor’s Office, and DNREC’s downstate campus in the circa 1863 Richardson & Robbins Building which borders Mirror Lake.

The environmental cleanup at Mirror Lake in Dover garnered national acclaim through use of a first-of-its kind activated carbon product called SediMite™. The project also was featured in an article in the scholarly Journal of Environmental Engineering, co-authored by several project participants, including two DNREC scientists. Titled “Full-Scale Application of Activated Carbon to Reduce Pollutant Bioavailability in a 5-Acre Lake,” the article noted that between 2013 and 2018 the project achieved approximately 80% reduction in PCB concentrations in sediment porewater, which is the water trapped between grains of sediment in the bottom of body of water. The study also documented an approximate 70% reduction in PCB concentrations in Mirror Lake’s resident fish.

DNREC scientists are currently working with project partners to develop a plan for a comprehensive 10-year post-remediation study of Mirror Lake carbon project, to include sediment, porewater, surface water and fish tissue sample analysis. Results from the study are planned to be released concurrently with DNREC previously planned fish tissue monitoring of the entirety of the St. Jones River system in the fall of 2024.

About DNREC
The Delaware Department of Natural Resources and Environmental Control protects and manages the state’s natural resources, protects public health, provides outdoor recreational opportunities and educates Delawareans about the environment. The DNREC Division of Watershed Stewardship develops and implements innovative watershed assessment, monitoring and implementation activities. Division of Waste and Hazardous Substances ensures Delaware’s wastes are managed to protect human life, health, safety and the environment. For more information, visit the website and connect with @DelawareDNREC on Facebook, Instagram, Twitter or LinkedIn.

Media Contacts: Nikki Lavoie, nikki.lavoie@delaware.gov; Michael Globetti, michael.globetti@delaware.gov


DNREC Mirror Lake clean-up earns more national acclaim; innovative approach reduces pollutants in the Christina River

DOVER, Del. – For Earth Day 2020, DNREC announced it has successfully used an innovative approach to reduce polychlorinated biphenyls (PCBs) in two Delaware waterways. Newly released scientific data are validating the new method of sequestering pollutants with activated carbon, which render them unavailable for uptake by fish and other aquatic organisms.

The first success was with an activated carbon product called SediMite™ at Mirror Lake in Dover in 2013. The project is featured in a new article co-authored by several project participants, including two DNREC scientists, and published in the May issue of Journal of Environmental Engineering. The article, titled “Full-Scale Application of Activated Carbon to Reduce Pollutant Bioavailability in a 5-Acre Lake” presents a summary of the monitoring data collected at the site between 2013 and 2018. Highlights include an approximate 80% reduction in PCB concentrations in sediment porewater, which is the water trapped between grains of sediment in the bottom of a water body. The study also found an approximate 70% reduction in PCB concentrations in Mirror Lake’s resident fish.

“The recognition by the Journal of Environmental Engineering reflects how Delaware is on the leading edge of environmental technology, an area that DNREC is exploring more and more” said DNREC Secretary Shawn Garvin. “Mirror Lake was a successful pilot, so DNREC’s team sought a second opportunity to try the technology.”

The A Street Ditch project became a focus for DNREC’s Watershed Approach to Toxics Assessment and Restoration (WATAR) Team after samples confirmed that drainage ditch sediments were a continuing source of PCBs to the Christina River. The project, in coordination with cleanup efforts at the adjacent South Wilmington Wetland Park site, provided an opportunity to evaluate an enhanced carbon sequestration technology developed by DNREC’s partners at the University of Maryland Baltimore County (UMBC).

The enhanced technology involves the use of SediMite™ with the addition of PCB-destroying micro-organisms (inoculant). In theory, the activated carbon will sequester PCBs, as shown in Mirror Lake. However, the micro-organisms (which exist naturally in the environment in much smaller numbers) will effectively degrade the PCB molecules over time. Initial results, collected only 5 months after the inoculated Sedimite™ was applied to the ditch sediments, show that total PCB concentrations in the top layer of sediments across the A Street Ditch study area dropped by an average of 25%. In addition, surface water PCB concentrations across the site area have dropped by an average of 35%. Most impressive is concentrations of total PCBs in sediment porewater have dropped by an average of 64%. Additional monitoring will occur in July 2020, and again in July 2022.

Another harbinger for clean water in Delaware is that sequestering or destroying legacy PCBs – the primary risk driver for most of the fish consumption advisories issued by DNREC and the Delaware Division of Public Health – prevents these contaminants from entering the food chain. With increasing confidence in these innovative sediment remediation technologies, DNREC is beginning to plan for larger-scale projects, in key watersheds across Delaware, with similar water quality impairments.

“What these projects have achieved brings the longstanding goal of clean water for all Delawareans a little closer,” said Secretary Garvin. “DNREC’s dedicated scientists and staff are committed to improving water quality and making smarter use of resources at our disposal, including the technology that has driven both the Mirror Lake and A Street Ditch projects.”

DNREC’s A Street Ditch pilot project was supported by $188,000 in Hazardous Substance Cleanup Act (HSCA) funds and a $30,000 US Environmental Protection Agency multi-purpose grant. For more information, view the DNREC YouTube video about the WATAR team’s A Street Ditch pilot and another video on the Mirror Lake project or visit the DNREC website.

About DNREC

The Delaware Department of Natural Resources and Environmental Control protects and manages the state’s natural resources, protects public health, provides outdoor recreational opportunities and educates Delawareans about the environment. For more information, visit the website and connect with DNREC on Facebook, Twitter or LinkedIn.

Media Contact: Micahael Globetti, michael.globetti@delaware.gov

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