Silica is listed as the 2nd most abundant material in the earth’s crust at 27.7% with only oxygen being more abundant at 47.7%. Silica is a dangerous threat to the human health when it becomes airborne.
As silica embeds itself into the lungs and the body builds permanent scarring around the silica, it reduces the ability to absorb oxygen. What happens when the body’s oxygen absorbing capacity is reduced by 5 or 10%? When the body’s ability to absorb oxygen is reduced, it can manifest itself into just about any illness or make any other pre-existing illness much worse. If people are suffering from silica exposure and their bodies have been deprived of oxygen, it could show up as or aggravate anything from headaches to cancer.
Asthma, COPD, lung disease, fatigue, shortness of breath, cold hands & feet, sleep apnea, Reynaud’s syndrome and headache are just a few symptoms of oxygen deprivation. That means that a lot of the unexplained illnesses people suffer from, including the elevated levels of degenerative neurological disorders within the elderly, could be explained by reduced oxygen absorption due to long term silica exposure. The levels involved may be too low for standard detection methods and, considering the exposure would be from sources that would not raise suspicion (such as an occupational hazard), doctors may not consider that specialized testing that would be required.
According to Ontario’s Occupational Health & Safety Act, the following chemical agents are prescribed as designated substances:
5. Coke oven emissions.
6. Ethylene oxide.
11. Vinyl chloride. O. Reg. 490/09, s. 2.
Both silica & asbestos cause permanent, irreversible damage in our lungs, reducing our ability to absorb oxygen. According to the global occupational health network:
“Epidemiological studies show that up to 30-50% of workers in primary industries and high risk sectors in developing countries may suffer from silicosis and other pneumoconioses (1). There is also a strong evidence of increased incidence of tuberculosis with the increasing severity of silicosis (2). In the World Health Report of 2002 (4), WHO estimated that 386,000 deaths (asthma: 38 000; Chronic Obstructive Pulmonary Disease (COPD): 318 000; pneumoconiosis: 30 000) and nearly 6.6 million disability-adjusted-life-years (DALYs)1 (asthma: 1 621 000; COPD: 3 733 000, pneumoconiosis: 1 288 000) occur yearly due to exposure to occupational airborne particulates. The actual total figure might be much higher since under-diagnosis and under-reporting are quite common (5). It is clear that occupational airborne particulates are an important cause of death and disability worldwide.”
The focus has been limited to workplace related silica exposure and very little consideration has been given to citizens exposed to lower levels of silica. People living downwind of a gravel pit are exposed to elevated levels of silica over long periods of time and their symptoms would manifest over their life and silica exposure may not be suspected.
Mine Safety and Health Administration
DVD563 (Was VC826) – 1938
This film (copied to videotape) was produced by the U.S. Department of Labor in 1938 and features an introduction by then Secretary of Labor Frances Perkins. This short black and white film presents the causes of silicosis and explains how the disease can be prevented. Stop Silicosis was shown as part of a Federal silicosis-prevention campaign that was initiated by Secretary Perkins.
Many American families have seen firsthand the tragic effects of silicosis. In this video from OSHA, learn more about their stories and how dust control methods can help limit workers’ exposure to crystalline silica.
All of the research suggests that the sand in a gravel pit would contain silica. At recent local CAP (Community Advisory Panel) meetings, the issue of silica was raised. It was stated by the pit’s proponents that silica is not an issue because the sand & gravel deposits in the area contain less than 1% silica content. In pressing for the data to prove this, it seems no scientific research has been presented – only opinions. The emissions from these sand and gravel pits have not been measured.
Here are a sample of the comments regarding silica made by Dufferin which can be found in the minutes of their CAP meetings. You can also find similar comments in the local papers:
- Kevin Mitchell explained that silica primarily comes from quartz or igneous rocks. The sand and gravel in Paris consists primarily of limestone. Silica is not a health risk in southern Ontario for sand and gravel pits.
- Kevin Mitchell explained that there is minimal silica in sand and gravel.
- Gustavo confirmed that glacial outwash does have some silica in it but it is granular and extremely minimal.
- Kevin Mitchell explained that there is a dust program in place on site so it would be rare to have any particles or dust blowing around because everything will be wet.
- Bill Galloway said that silica is not an issue in Brant County because of the geology and if it were an issue, Dufferin Aggregate would not be here.
- In southern Ontario silica is not an issue because almost none of the sand and gravel contains silica.
- To date, there have been no silica related health issues at any Dufferin Aggregates site.
- Kevin Mitchell explained that southwestern Ontario does not contain the amount of silica that would be a concern for Dufferin Aggregates sites.
- Bill Galloway explained that there has been over 20 years of monitoring that confirms silica is not a concern and says there has never been an issue at a Dufferin Aggregates pit in regards to silica.
- Richard Erdmann explained the geology in Paris simply does not support the presence of silica and therefore it is not a concern.
- Bill Galloway said if silica were a problem at the Paris Pit, Dufferin Aggregates would not operate.
The scientific testing at a gravel pit just a 5 minute drive north tells a different story. According to recent scientific studies at the proposed Preston Sand & Gravel Pit, located on HWY 97 in North Dumfries (just up by the 401),SILICA CONTENT OF HENNING PIT FEED MATERIAL, NORTH DUMFRIES, ONTARIO
Golder Associates Ltd evaluated of a sample of sand and gravel from the vicinity of the proposed Henning Pit. The purpose of the analyses was to identify quartz and silica content in the sand and gravel. “The overall quartz and silica content of the sand and gravel sample received from the vicinity of the proposed Henning Pit was determined to be 15.7%, with the gravel and cobbles fraction contributing 7.4% and the sand fraction contributing 8.4%, proportionately weighted based on the graduation.
“free” or unbound quartz and silica content is therefore guaged to be approximately 8.4% of the raw material.”
details can be found on page 7 Golder Letter — Silica Content Analyses(1)
This report was presented at a CAP meeting and the following response was noted in the minutes:
“Kevin Mitchell reviewed the report and read out loud from the report that an individual stone (sample size piece of granite) contained 17% silica but that the bulk sample (the entire deposit) contains less than 1% silica which is similar to all other sites in southern Ontario”.
Below is an air quality expert’s read on the report:
I read your email with interest. Franco DiGiovanni, who I worked with on the CRAND case, has extensive experience and expertise in this area; I can provide further details of his credentials in geology and air quality if you wish. I have discussed your email with him and we have the following comments.
The proponents for the Henning Pit (Preston Sand and Gravel [PSG]) hired a consultant to assess likely air emissions from the proposed pit. We reviewed their consultant’s report, as part of our retainer with CRAND, and found the assessment wanting in many aspects. One of the aspects was their estimate for maximal crystalline silica content of the aggregate that could be extracted (as this would represent the silica content of the dust emissions). PSG’s consultant claimed a maximum of 20% but we found that it could have been more; interestingly PSG did not provide any analysis of the actual aggregate to corroborate their claim.
PSG also provided the Golder report you mentioned. The problem with that report is that they did not identify the sample location; without knowing the sample location we have no idea whether the samples analysed would be representative of the actual aggregate to be extracted. Given that basic problem we didn’t bother to review the Golder report in any great detail; thus, we are not sure how much credence can be placed on it.
I provide a copy of an Ontario Government report, provided to us by PSG’s consultant . Page 31 (Table XIII) indicates that unconsolidated sand deposits can have up to 99% crystalline silica; so it demonstrates that it is possible to have appreciable levels present. It is up to the aggregate producer to provide analysis data indicating the level of crystalline silica in the deposit they are extracting.
I am not sure why Misters Mitchell and Galloway would make the statements you have highlighted in your email. I would like to see the data that backs-up their assertions; especially I would like to see the evidence that “silica is not a health risk in southern Ontario for sand and gravel pits.” To make such an assertion requires significant data and analysis and I would very much like to see the reports or evidence that Mr. Mitchell has for that.
However, it is also important to realize that it is not only crystalline silica that may be a concern, but also other components of the dust; analysis data would be required to ascertain the situation. The dust itself, especially the very fine fraction of dust (“PM2.5”), may be an even bigger concern and should not be ignored as part of the analysis.
As regards your other questions, about sampling and a study, it may be best that we discuss these first.
Nicole Shantz, PhD
Air Quality Scientist
Airzone One Ltd.
The following came from an air quality report prepared by RWDI:
For unconsolidated sand in Southern Ontario, Hewitt (1963) reported that the sands of Ontario are usually not high in silica. Measured values of free silica content were in the range between 17 and 62%. At sites closest to the North Dumfries area (Malton, Milton, Maple, Clarkson, Niagara Falls area), it ranged from 17 to 43%, with an average of approximately 32%. (page 37 silica in ontario)
Dust generated at the proposed Henning Pit will originate from a combination of unconsolidated sand and limestone gravel at the site. As such, the silica content in the dust will generally lie between that of sand and limestone. For this study, a middle value of 20% has been assumed.
Details can be found on page 15 Lepage AQ Final Report – revised Dec 2013
The following is from a human health risk assessment:
Dust generated at the proposed Henning Pit will originate from a combination of unconsolidated sand, and limestone gravel at the site, with the largest potential source of dust arising from truck movements on unpaved haul roads. Based on this, RWDI (2013) did additional analysis on the available information on the percentage of silica present within the dust emitted from the site, and assumed a middle value of 20%. Refer to the Air Quality Assessment report (RWDI, 2013) for the detailed methodology for this calculation.
Details can be found on page 35 SLHHRA of Henning Pit Emissions – Dec 13, 2013
In witness testimony reviewing the air quality assessment by RWDI, Dr. Giovanni was arguing that the 20% silica value used in the report was too low;
In regards to choosing an overall proportion of crystalline silica RWDI admittedly chooses a “middle” value (20% of the composite aggregate) rather than a worst-case value. This is chosen despite the lack of site-specific information, thereby rendering the data used uncertain as well as not worst-case. RWDI would seem to assume (although it is not clear) that all of the aggregate extracted will be formed of equal proportions of limestone and sand whereas different areas of aggregate may have higher portions of sand and therefore contain higher proportions of silica. RWDI have not chosen a conservative, worst-case value, and so does not demonstrate an abundance of caution.
Details can be found on page 15 2013 12 13 F. DiGiovanni Witness Statement
This data should, at a minimum, cast doubt on the public statements made by Dufferin that there is less than 1% silica in the sand & gravel deposits of Southwestern Ontario. I believe that it is imperative that a company operating on top of drinking water to be totally open and honest.
Could it be that many of the respiratory problems suffered by those who live around gravel pits were caused by the silica in the dust they emit? Imagine the repercussions of that. That might motivate some to hide the truth.
And…Silica is just one of many harmful substances hidden in the dust emitted from gravel pits.
Here is some more info if you are not yet convinced.