In consideration of the upcoming Soil and Groundwater Forum taking place on April 21, at the Calgary Petroleum Club, PTAC would like to highlight one of the Soil and Groundwater Committee’s many success stories, the “New Boron Guidelines”. In 2008 the PTAC Soil and Groundwater Committee identified Boron as an upcoming policy issue/knowledge gap and as a result seven research projects were completed over the next seven years which fed into the creation of new Boron Guidelines – there will be more on this project and many others related to soil and groundwater issues at the upcoming Soil and Groundwater event this week . These are your last day’s to register for this event! Members rate slashed from $595 to $95.
FEATURED PROJECT: New Boron Guidelines Literature indicates that boron is naturally present in soil and groundwater systems from decaying plant material and weathering of boron-containing minerals. Industrial boron sources include fertilizers, herbicides, cleaning agents, produced water and drilling waste.
The challenge faced by our team was to find a science-based method to determine natural versus anthropogenic boron concentrations. In some cases, environmental site assessments recommended remedial programs without reliable boron soil concentrations, i.e. without differentiating natural versus anthropogenic boron concentrations, and bioavailability. Natural boron concentrations are only partially available to plants.
PTAC formed the Boron Working Group to develop risk and science-based soil guidelines. The initiative consisted of extensive consultations with Alberta Environment & Parks and Alberta Energy Regulator, literature review, numerous field trials, and research on laboratory methods.
The project was successful as field trials showed evidence of healthy plant growth with soil concentrations above 2 mg/kg using the current method in a variety of species across Alberta and Saskatchewan.
A modified laboratory soil extraction method was also identified to predict toxicity to plants. The existing soil extraction method of Hot Water Soluble (HWS) boron measured total boron concentrations in soils rather than boron concentrations bioavailable to plants. The modified soil extraction method of Saturated Paste extracted only the available boron concentrations. The Saturated Paste method turned out to be a better predictor of plant toxicity including fate and transport of dissolved boron concentrations in soil and groundwater.
In December 2015, Alberta Environment and Parks released a Draft Guideline for public comment, Soil Remediation Guidelines for Boron: Environment and Human Health. The document outlined the new boron guidelines now incorporated in the February 2nd, 2016 edition. The most stringent soil guideline was 3.3 mg/L for Natural, Agricultural and Residential/Parkland based on direct soil contact to plants. The commercial and industrial land was 5 mg/L, limited by the fresh water aquatic life pathway. These values were based on Saturated Paste soil extraction methods.
The updated risk and science-based boron soil guidelines bring the following benefits; reducing investigation time, focusing remediation efforts, preventing unwarranted landfill disposal, and improving soil conservation.
A list of the PTAC funded boron research projects that contributed to this initiative can be found at http://www.ptac.org/ or http://auprf.ptac.org/