Back in April I wrote a piece on the wisdom of dumping contaminated soils in the Shawnigan Lake watershed. I visited the region with Shawnigan Lake Area Director Sonia Furstenau. Together with a few other Shawnigan Lake residents, we hiked around on parkland owned by the Cowichan Valley Regional District. I took this opportunity to take a number of photographs. More importantly, I took the opportunity to collect water samples.
The results of these water samples, together with my observation that a significant amount of fill had over run Lot 21 and was on the neighbouring parkland, led me to subsequently ask the Minister of Energy and Mines and the Minister of Environment questions in Question Period.
As background, Lot 21 is the property located at 638 Stebbings Road and is owned by 0782484 B.C. Ltd. For several years, soil has been dumped Lot 21 for later use to backfill the quarry in lot 23. A photograph of the northern boundary wall of deposited soils is shown to the left. This photograph was taken from CVRD Parkland on the north side of Shawnigan Creek.
I outlined in my earlier post that it was apparent to me that substantial amounts of building materials had been placed on Lot 21. There was also clear evidence that runoff from this site failed drinking water standards at the point of entry with Shawnigan Creek. And visually, this water looked nothing like any other water in nearby surface and running water (see image to the right).
On May 15th I went back to the area to get a better sense as to what metals were contained in the orange sediments under the orange water. Since the water runoff came from Lot 21, my goal was to determine if sediments in this stream were any different from sediments at a control location upstream of Lot 21.
Four different sediment samples were obtained. Two of the samples were collected upstream of Lot 21 in order to obtain a control sample. The first, termed FLOW, in the attached data, was taken in the middle of Shawnigan Creek (see Figure 1 below). FLOW data will be used as the control sample below. The second sample (BANK in the attached data) was located at the bank of Shawnigan Creek immediately adjacent to where FLOW was collected.
The third and fourth samples were collected where the orange runoff entered Shawnigan Creek (Figure 2), The third, termed CREEK, in the attached data, was taken in Shawnigan Creek right at the location where the runoff enters the creek. The fourth sample was obtained about a metre upstream of the runoff stream. This is termed POOL in the attached data.
Figure 2: Photographs showing me collecting the sediment samples at the location where the Lot 21 runoff meets Shawnigan Creek (left) and in a pool a metre or so upstream of the creek in the covenant along Shawnigan Creek (right).
As in my earlier post, the metal contents in the sediments were determined using an inductively coupled plasma mass spectrometry (ICPMS). The method for the bulk analysis of acid extractable elements (that is trace elements not bound in silicate minerals) was as follows:
1) The vial was shaken to homogenize and all for the removal of an aliquot for analysis (2 mL aliquot for BANK and POOL, 10 mL aliquot for CREEK and FLOW).
2) 10 mL of 8 Molar Environmental Grade Nitric Acid was added and allowed to react overnight.
3) The sample was diluted to 50 mL with 18 mega ohm deionized water.
4) The mixture was shaken to homgenize
5) The sample was put in a centrifuge for fifteen 5 minutes at 3000 rpm to separate out any residual particulate.
All concentrations in the attached data are given in (μg/L). Since there were different amounts of sediments in the individual samples, it is not possible to directly compare their element concentrations. Rather, I will focus on what is called the enrichment factor for each element after normalization with the commonly occurring element Calcium (Ca).
By definition then, the enrichment factor of a mineral XX is:
Here [sample] refers to the concentration in a collected sample (in μg/L) and [control] means the concentration in the control sample (also in μg/L).
The attached data clearly show the presence of an enriched industrial metal content of the POOL Sample.
The following elements were found to be enriched by:
Between three and four times the control values:
Magnesium (Mg), Vanadium (V), Chromium (Cr), Manganese (Mn), Cobalt (Co), Molybdenum(Mo), Caesium (Cs), Barium (Ba), Hafnium (Hf).
Between four and five times the control values:
Lithium (Li), Scandium (Sc), Germanium (Ge), Zirconium (Zr), Tin (Sn).
Between five and ten times the control values:
Niobium (Nb) [enriched 5.29 times higher than control]; Lead (Pb) [enriched 5.19 times higher than control].
Greater that ten times the control values:
Iron (Fe) [enriched 11.69 times higher than control]; Thorium (Th) [enriched 18.60 times higher than control].
After examining the elemental sediment analysis, I am left with a number of serious concerns. The enriched metal values in the sediments under the runoff leaving Lot 21 suggest that their source comes from somewhere upstream and likely within Lot 21 itself. The question I am left with is this:
What, if anything, has been buried on Lot 21 that could produce the Thorium, Lead and other heavy metal enrichment in the sediments?