Engineered (bioretention) media organic material properties and specifications

Engineered (bioretention) media organic material properties and specifications.
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Property	Biochar	Coir	Compost	Peat	Wood chips
Phosphorus leaching	No [1]	No to slight [2]	Yes [3]
Phosphorus retention	No to slight [4]	No [5]	No
Handling concerns	Potential explosive concerns in closed space situations; volatile compounds (depending on pyrolysis temperature) [6]	Dust [7]	None
Soil hydraulic properties	Significant improvement [8]	Significant improvement [9]	Significant improvement [10]
Soil physical properties	Significant improvement [11]	Moderate improvement [12]	Significant improvement [13]
Plant/microbial effects	Beneficial but varies with feedstock [14]	Beneficial [15]	Beneficial if not fresh [16]; [17]
Availability	Multiple distributors [18]	Widely available [19]
Specifications/standards available	Limited due to variability with feedstocks [20]	Yes [21]
Cost
Research needs	Feedstocks suitable for stormwater applications	Phosphorus fate in stormwater applications
Applications	[22]	[23]
Chemical properties	[24]	[25]
Sustainability	Sustainable, but has current market constraints [26]	Sustainable [27]
Potential contaminants	Minor risk - metals and polycyclic aromatic hydrocarbons (PAHs) [28]	Low risk - possible chloride depending on preparation method [29]
Test methods	Not standardized but International Biochar Initiative widely used [30]	Not standardized but multiple methods available [31]
Effects of aging/Life expectancy	Varies with production method [32]	Decomposes slowly unless nutrients are added [33]
Notes	Characteristics vary with feedstock and pyrolysis temperature	Coir must be composted or incorporated with compost, lime, fertilizer, and/or microbes