Standardized Product Definition and Product Testing Guidelines for ...

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4.2 Test Category B - Toxicant Reporting
In addition to Test Category A thresholds and declarations, all biochar materials must meet the
soil toxicity assessment thresholds as outlined in Table 2 below. Toxicants may be divided into
two categories – those that may be present in the feedstocks used (metals and polychlorinated
biphenyls) and those that may be produced by the thermochemical process used to make
biochar (polycyclic aromatic hydrocarbons, and dioxins).
Biochar made from processed feedstocks may carry additional risks from the potential presence
of toxicants in the feedstock and must meet the toxicant assessment testing frequency
requirements of Section 6.
Biochar toxicity assessment reporting follows commonly identified soil toxicity and chemical
content reporting requirements for soil amendments, composts and fertilizers. The threshold
values in Table 2 are given as a range of values based on standards for soil amendments or
fertilizers from a number of countries. 2 The Maximum Allowed Thresholds (MAT) indicate
toxicant levels above which the material would not be considered acceptable. In order to meet
the requirements of these Biochar Guidelines, reported toxicant levels must be below the MAT
that has been established in the area of jurisdiction where biochar is produced and/or intended
for use. If the area of jurisdiction where the biochar will be used has no threshold at all for a
particular toxicant, the biochar must be below the highest maximum value established below for
each specific toxicant. See Appendix 3, Toxicant Assessment and Determination of Thresholds,
for more information.
Table 2: Test Category B Characteristics and Criteria
Test Category B: Biochar Toxicant Reporting - Required for All Feedstocks
Requirement
Earthworm Avoidance
Test
Germination Inhibition
Assay
Polycyclic Aromatic
Hydrocarbons (PAH)
Range of
Maximum
Allowed
Thresholds
6 – 20
Dioxin/Furan (PCCD/F) 9
Pass/Fail
Pass/Fail
mg /kg
TM
ng/kg I-
TEQ
Test Method
ISO 17512-1:2008 methodology and OECD
methodology (1984a) as described by Van Zwieten et
al. (2010), see Appendix 3
OECD methodology (1984b) 3 test species, as
described by Van Zwieten et al. (2010), see Appendix
3
Method following US Environmental Protection Agency
(1996)
Method following US Environmental Protection Agency
(2007)
2 The following jurisdictions were used to construct the range of values: Australia, Canada, EU, UK, USA.
These entities were chosen as standards because they all have a long history of regulations addressing
these toxicants in soils and other substrates.
Standardized Product Definition and Product Testing Guidelines for Biochar That Is Used in Soil 13