Engineered (bioretention) media organic material properties and specifications

Engineered (bioretention) media organic material properties and specifications.
Link to this table

Property	Biochar	Coir	Compost	Peat1	Wood chips
Phosphorus leaching	No [1]	No to slight [2]	Yes [3]	No [4]	No
Phosphorus retention	No to slight [5]	No [6]	No	Yes [7]	No
Handling concerns	Potential explosive concerns in closed space situations; volatile compounds (depending on pyrolysis temperature) [8]	Dust [9]	None	None	Possibly dust [10]
Soil hydraulic properties	Significant improvement [11]	Significant improvement [12]	Significant improvement [13]	Significant improvement	Improvement if incorporated [14]
Soil physical properties	Significant improvement [15]	Moderate improvement [16]	Significant improvement [17]	Significant improvement	Improvement if incorporated [18]
Plant/microbial effects	Beneficial but varies with feedstock [19]	Beneficial [20]	Beneficial if not fresh [21]; [22]	Beneficial	Beneficial for fungi
Availability	Multiple distributors [23]	Widely available [24]	Widely available	Sphagnum peat is available in Minnesota & Canada	Widely available
Specifications/standards available	Limited due to variability with feedstocks [25]	Yes [26]	Yes [27]	Minnesota DOT Spec 3880, United States Golf Association Green Section, OMRI, Canadian Peat Association	Yes for chips used for energy production [28]
Cost				Variable with distance of delivery
Research needs	Feedstocks suitable for stormwater applications	Phosphorus fate in stormwater applications	Identifying compost-containing media mixes that do not leach phosphorus but provide other benefits	Metal/hydrocarbon/contaminant loading data by peat type	Extensive needs since there are limited studies in stormwater applications.
Applications	[29]	[30]	[31]	Stormwater mixes, horticultural applications, rooftop garden mixes, golf & athletic mixes	[32]
Chemical properties	[33]	[34]	[35]	Natural organic material	[36]
Sustainability	Sustainable, but has current market constraints [37]	Sustainable [38]	Sustainable	Slowly renewable, Canadian Peat Association information available	Sustainable
Potential contaminants	Minor risk - metals and polycyclic aromatic hydrocarbons (PAHs) [39]	Low risk - possible chloride depending on preparation method [40]		Low risk	Low risk; avoid CCA and creosote-treated sources [41]
Test methods	Not standardized but International Biochar Initiative widely used [42]	Not standardized but multiple methods available [43]	[44]; [45]	Not standardized, but some methods available in ASTM4427	[46]
Effects of aging/Life expectancy	Varies with production method [47]	Decomposes slowly unless nutrients are added [48]	Ages relatively rapidly; aging generally benefits stormwater function by reducing nutrient loss and reducing microbial competition for nutrients [49]	Stable	Slow to moderate depending on source and application conditions [50]
Notes	Characteristics vary with feedstock and pyrolysis temperature	Coir must be composted or incorporated with compost, lime, fertilizer, and/or microbes
1We did not conduct an extensive review for peat. Sources of information include the Canadian Peat Association