Summary of public comments received on the draft Federal Environmental Quality Guidelines for Strontium
Comments on the draft Federal Environmental Quality Guidelines for Strontium were submitted by Alberta Environment and Parks, British Columbia Ministry of Environment and Climate Change Strategy, and Ontario Ministry of Environment, Conservation and Parks.
Summarized public comments and responses are provided below, organized by topic:
Topic 1: Editorial
| Summarized comment | Summarized response |
|---|---|
| Various editorial comments were received to improve the clarity and flow of the factsheet. | With the exception of comments related to the introduction section (e.g. how FEQGs are used and why they are developed via the FEQG forum), all editorial suggestions were incorporated into the factsheet. More details, such as what are FEQGs, why and when they are developed and how they differ from CEQGs are available online. |
| Qualify whether strontium’s mode of action in fish and algae is applicable to invertebrates. | There is no literature to support strontium’s mode of action in fish and algae is also exhibited in invertebrates so no change was made to the factsheet. |
Topic 2: Methodology
| Summarized comment | Summarized response |
|---|---|
| Why were data from McPherson et al. (2014) not used in guideline derivation? | Text was added to factsheet to qualify, in general terms, why some endpoints from McPherson et al. (2014) were not used. An internal ECCC report, documenting which data points were included/excluded from McPherson et al. (2014) in FWQG derivation, is available upon request at ec.rqe-eqg.ec@canada.ca. |
| How was the quality of key reference study (Pacholski 2014) assessed? | One unpublished (Pacholski 2009) and one confidential report (Hydroqual 2009) confirm standard toxicity test methods were followed for the endpoints reported in Pacholski (2014). The test concentrations were nominal so data were rated secondary. |
| Guideline derivation should not rely on one study for most endpoints. | The revised guideline is based on toxicity data from four studies. Two of five endpoints from Pacholski (2014) were corroborated with data from two other studies, negating the risk of systematic errors occurring at lab scale. |
| Why was C. dubia IC10 (Pacholski 2014) used instead of C.dubia IC20 (McPherson et al. 2014)? | An internal ECCC report, documenting which data points were included/excluded from McPherson et al. (2014) in FWQG derivation, is available upon request at ec.rqe-eqg.ec@canada.ca. |
| How do the HC5 estimates from SSDMaster and ssdtools compare? | HC5s from ssdtools are marginally lower but within the same order of magnitude as that of SSDMaster. An additional data point was added to the toxicity dataset, and ssdtools was subsequently used to derive a revised FWQG (i.e. 2.5 mg/L) so a comparison to SSDMaster is no longer required. |
| Can the 95% confidence interval be reported in Figure 1? | The revised factsheet provides 95% confidence intervals in Figure 1. |
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