Calcium Chloride
Government documentation, particularly a report prepared for The Ontario Ministry of the Environment and Energy, gave calcium chloride the lowest (most
favorable) toxicity rating among several dust suppressants tested. This report is entitled "A Study of Dust Suppressants in Ontario - Final Report." The table below presents results of aquatic toxicity tests carried out on sample of the traditional dust suppressants.
Both calcium chloride (35% solution) and oil field brine
received the lowest toxicity ratings (Grade 0) in this study indicating the environmental advantages of using these products.
| Dust Suppressant |
Test Species |
| Rainbow Trout (96 h LC50) |
Daphnia Magnia (48 h LC50) |
| Concentration (mg/L) |
95% Confidence Interval (mg/L) |
Concentration (mg/L) |
95% Confidence Interval (mg/L) |
Toxicity Rating |
Calcium Chl.
Oil Field Brine
Road Binder
Tembind
Dust Bond
DCS-225 (3:1) |
14,857
52,305
4,337
657
535
191 |
12,440-17,742
44,099-62,037
3,877-4,851
589-731
469-609
166-218 |
6,387
24,000
1,342
3,536
625
521 |
5,273-7,763
18,000-32,000
1,000-1,800
2,500-5,000
55-71
415-727 |
Grade 0
Grade 0
Grade 1
Grade 2
Grade 2
Grade 2 |
Note: Based on aquatic toxicity rating system developed by IMCO/FAO/UNESCO/WHO, 1969. Grade ratings vary from 0-4, using the following ranges, and evaluated based on
toxicity results for rainbow trout:
Grade 0 -- 10,000 ppm Grade 1 -- 1,000 - 10,000 ppm Grade 2 -- 100 - 1,000 ppm Grade 3 -- 1 - 100 ppm Grade 4 -- 1 ppm
Other products, such as Road Binder (Grade 1) and Tembind (Grade 2), received inferior ratings. In fact, the report claims that "lignosulphonates in streams may cause
discoloration and foaming and reduce biological activity." The report also says that "dioxins compounds, including octachlorodibenzodioxin and heptachlorodibenzodioxin were detected in samples of Tembind and Road Binder pulping liquors."
Note: Calcium chloride is odorless,
colorless, and inflammable. Under current laws it is not regarded as a hazardous material and therefore does not require "hazardous material" placarding on transporting vehicles.
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