Nitrogen Cycling in the Environment – Investigation, Transformation, and Remediation


Nitrogen is critical to sustaining life on Earth. While cycling through the environment, nitrogen comes in many forms that are variable in their utility to organisms, mobility across environmental media, and toxicity; either directly (methemoglobinemia in infants) or indirectly (eutrophication leading to harmful algal blooms). Regulatory programs are often focused on management of a particular component of the nitrogen cycle, sometimes in a vacuum: removal of ammonia-nitrogen from surface water treatment ponds prior to discharge or remediation of nitrate and nitrite-nitrogen in groundwater for example. In reality, nitrogen cycling is driven by a series of reactions that primarily transform nitrogen species in the environment rather than removing them, which can lead to recurrent environmental issues if the ‘total nitrogen’ perspective is not well understood. This presentation will provide background on the total nitrogen perspective, including a discussion of relevant transformation (and removal) reactions and examples of applications (and consequences) for investigation and remediation approaches.

The Presenters

Brent Lazenby, M.Sc.

Senior Scientist, Geosyntec

Brent Lazenby is a senior scientist based in Louisiana with Geosyntec Consultants, Inc. (Geosyntec) with more than 10 years of multi-media monitoring, investigation, and remediation experience. Brent’s day-to-day work focuses on geochemical/hydrogeological evaluations in support of in-situ groundwater remediation (using bioremediation, phytoremediation, zero-valent iron, etc.) and management of nitrogen compounds in soil, surface water, groundwater, and sediment. Prior to living in Louisiana, Brent grew up in Ontario where he attended university with studies focused around nitrogen cycling in soil, surface water, and groundwater. He has had the good fortune to work with nitrogen in the environment across sites located in the United States of America, Canada, and Australia and welcomes discussion around management and remediation of nitrogenous compounds.

Phil Dennis, M.A.Sc.

Principal Scientist, SiREM

Phil is a Principal Molecular Biologist with more than 20 years of experience focused environmental microbiology, molecular genetic testing, enhanced bioremediation and technology commercialization. He currently directs the molecular testing services, next generation sequencing and is the innovation lead for SiREM’s research and development program. He has also played a leading role in developing relationships with many universities and serves on the Board for University of Waterloo Center for Microbial Research.