Customized, Comprehensive Testing for MNA

In monitored natural attenuation (MNA), natural physical, chemical, and biological processes are analyzed so practitioners can prove that compounds of concern are being destroyed, degraded to non-toxic compounds, or immobilized in a reasonable amount of time, protecting human health and the environment.

Natural Attenuation Testing for VOCs with SiREMNA

The most common natural attenuation mechanisms at sites with chlorinated volatile organic compounds (cVOCs) are anaerobic biodegradation and abiotic, or chemical, reduction. SiREMNA is an analytical testing suite that provides comprehensive data for analysis of the multiple biotic and abiotic degradation pathways which are critical for successful natural attenuation.

The analyses can be performed directly on aquifer materials or used to complement SiREM’s bench-scale treatability testing services, including batch microcosm and column testing to accomplish the following:

  • Characterize site conditions to evaluate whether MNA is a viable remediation option.

  • Assess whether biotic degradation of cVOCs that is already occurring is effective and sustainable.
  • Determine the role of abiotic reductive dechlorination by biogenic reactive minerals that occur in naturally reducing aquifers, and include iron sulfides, green rusts, pyrite, magnetite, biotite, and siderite.
  • Support, design, and monitor performance of enhanced in situ chemical reduction (ISCR).
  • Assess the role of abiotic dechlorination by biogenic reactive minerals formed by iron- and sulfate-reducing bacteria at enhanced reductive dechlorination bioremediation applications.

*Adsorption onto iron oxyhydroxides is shown.

Natural Attenuation Testing for Inorganic Compounds with SiREMNA

Under certain conditions, natural attenuation can reduce the mobility, toxicity, and bioavailability of inorganic materials by precipitation as new minerals, co-precipitation, adsorption to the surfaces of soil particles, or incorporation into soil particles.

In contrast to fully degrading or destroying organic compounds, inorganic attenuation often involves immobilizing compounds. These processes can sometimes be reversible.

SiREM has a comprehensive testing package to evaluate the viability of MNA remedies for metals and other inorganic compounds of concern. The package will assess the viability of MNA and guide testing protocols for MNA remedies and includes:

  • Characterizing the chemical and mineralogical properties of aquifer solids that are able to attenuate compounds of concern.
  • Understanding the aqueous- and solid-phase chemical speciation of compounds of concern within the plume.

  • Measuring immobilization and sequestration processes that can help attenuate compounds of concern.
  • Collecting site-specific data to demonstrate the long-term stability of immobilized inorganic constituents.

Clients turn to SiREM’s SIREMNA testing to understand if and how compounds of concern are naturally attenuating at their sites.

Consider our robust and customizable SIREMNA packages, which add chemical and Gene-Trac® testing to our comprehensive treatability tests and are designed for your site based on media, compounds of concern, microbes present, and other features. These packages evaluate the viability of MNA for both organic and inorganic compounds to support effective best-value solutions for your site.

Because our studies use soil, sediment, rock, and groundwater from your site, we can monitor changes in dissolved concentrations of organic and inorganic compounds and give you robust evidence that conditions at your site are poised to break down or attenuate the compounds you are targeting.

Ready to apply SiREMNA to your site?

We help you select the best tests to use for a specific pollutant and site. We provide support as you sample at your site, and we help you interpret results.