Golder’s Response to Dave Harris’ Submissions to MOE on Jan 24 and
Feb 7, 2011 regarding Testing of Samples Collected near the Landfill
February 11, 2011
The instructions to Golder were to comment on the items listed below in blue, and any
other concerns they may have regarding Dave’s submission. Golder’s response is
shown in red.
Appropriateness of the “Spring-at-the-Bridge” Sample Site:
Geophysics data from Seismic Lines 3 and 4 from the 1993 Agra Closure Report shows
that the bedrock surface rises to the east in the area downgradient of the landfill site.
Hydrogeological information indicates that most groundwater flow occurs within the
regional flow zone above the bedrock surface, so the direction of groundwater flow in
the regional groundwater flow zone is likely controlled by the bedrock profile. Based on
this profile, it is unlikely that regional groundwater flow from the landfill site is directed as
far east as the bridge. Therefore, the “Spring-at-the Bridge” site is not considered a
representative downgradient sampling location.
… Springs 1 through 5 were identified by AGRA in the early 1990’s by site
reconnaissance as being located along a “seepage zone” downgradient of the landfill.
All five springs were sampled and S1 was retained as part of the monitoring program
because at that time it had the highest concentrations of constituents.
Metals Testing: It appears they did extractable metals. Perhaps they should have done
total metals?
I noticed that the first laboratory report (Lot ID 779538) referenced “extractable” metals
analysis while the second lab report (Lot ID 785348) referenced “total” metals. In both
reports, anions were reported as “dissolved”. I called the lab (Exova) to inquire why
different methodologies were used. The lab manager stated that extractable metals
analysis consists of acidifying the sample in the lab and digesting prior to analysis. He
stated that extractable analysis is considered appropriate for analysis of groundwater
samples for drinking water applications where the turbidity is less than 1 NTU. When I
pointed out that turbidities of up to 310 NTU had been reported for the samples, the lab
manager stated that the extractable analysis was likely not appropriate methodology in
that instance and that a total metals analysis should have been used. The lab manager
stated that total metals analysis is typically conducted by the lab on drinking water
samples when the turbidity or colour of the water is observed to be high. The
acidification process for total metals is reportedly more “rigorous” whereby the samples
are acidified and digested on a hot block for a couple of hours prior to analysis to
ensure everything has been digested. In contrast, dissolved metals analysis (which was
only conducted for the anions) consists of filtering with a 45 micron filter followed by
acidification prior to analysis.
Typically, groundwater from monitoring wells is subject to dissolved metals analysis
because the groundwater inherently contains small particles of sediment, which, if
digested, can provide anomalous metals results. As such, the monitoring wells that are
sampled at the site by Golder are analysed for dissolved metals. To ensure that no
changes in the metals concentrations occur before the lab analysis, the samples are
filtered and acidified in the field (rather than the lab). If groundwater samples were
being collected from a drinking water supply well, total metals analysis would typically
be conducted because the groundwater is not typically filtered prior to consumption.
For springs, the standard practice is to sample for total metals. However, any sediment
contained in the spring samples has the potential to be digested and produce
anomalous metals results. In these instances, consideration could be given to running
both total and dissolved metals analysis to determine the sediment contribution.
I looked at the chemistry data from the attachments and noted that the turbidity at the
spring located mid-slope is high (310 TU). Presumably, based on this number there
was a high amount of sediment in the sample, which could account for the higher
concentrations of total metals at that location.
Use of the CDWS: Is this the right standard? If not, why not?
The Contaminated Sites Regulation (CSR) is considered to be applicable to the site.
Given that the ultimate receiving environment is Powell River, the CSR standards for
Freshwater Aquatic Life are considered to be the applicable CSR standard. In our
annual reports, we have also compared the results to the CSR drinking water
standards. However, Technical Guidance 6 on Contaminated Sites related to Water
Use Determination has just come into effect as of February 1, 2011. It states that the
standards for drinking water use applies in instances where drinking water wells or
surface water intakes are located 100m upgradient and 500 m downgradient of the
outer extent of the contamination source. There are no drinking water wells located
downgradient of the site and the springs are not being used for consumptive purposes.
We understand that water derived from the Mill Filterhouse for the mill site is not being
used for drinking water purposes. While there is a municipal drinking water intake from
Powell Lake, it is located at One Mile Bay located approximately 1.5 km upstream of the
site. Based on these factors and the new Technical Guidance document, we would not
interpret the drinking water standards to apply.
Well 98-5: What is the current status of this well? Why is it not part of our normal list of
monitoring wells? Was it tested in 1998, and if so, what can you conclude from the
differences in results for that well then versus Spring 1 now? Does it indicate a
“different water flow” as Dave suggests?
Well 98-5 was installed in 1998 in response to a recommendation from Environment
Canada’s consultant. The purpose of the well was to further characterize the quality of
groundwater entering Powell River and to provide a comparison with the spring S1
chemistry. Due to poor access to this area, the well was installed using a portable geoprobe sampling device and as a result was not constructed in accordance with standard
monitoring well design (which has provisions for a sand pack and surface seal). The
well was screened over an interval of 1.1 m to 2.6 m below ground surface. Samples
from 98-5 were sampled for both total and dissolved metals. A number of total metals
were found in excess of applicable criteria, which were attributed to the high silt content
of the sample (which was not surprising considering the manner in which the well was
installed). In contrast, the dissolved metals from 98-5, which were field filtered prior to
acidification, yielded significantly lower concentrations of metals. The dissolved metals
concentrations from 98-5 were lower or comparable to the totals metals from the Spring
S1, so my recollection is that Environment Canada’s recommendations were satisfied
and further sampling at 98-5 was not required.
Sampling at Spring 1 in December 2010: Please confirm we (i.e., Paige) did this in
2010. It was 2009 that we did not do this.
Sampling of Spring S1 was conducted by Golder on December 4, 2010. No detectable
dioxins and furans were found in that sample.
The annual monitoring program is carried out in accordance with an approved Health
and Safety Plan to ensure the protection of field staff. The sampling of the Spring S1
during the wet season of 2009 was deferred from December 2009 until March 2010
because the high lake levels in December 2010 precluded accessing the Spring S1 in a
safe manner.
Powell Lake level was 280.8 on Dec 4, 2010 while the average lake level in December
of 2009 was 282.6.
Receiving Environment: Dave has indicated the spring at mid-slope is within the
receiving environment. Do you agree with this?
In our opinion, the receiving environment is Powell River. The Spring (S1) represents a
location close to where groundwater discharges from the site to the receiving
environment, so it is considered a good monitoring site. We would not consider springs
discharging mid-slope to represent the receiving environment (unless water from those
springs was being used for consumptive purposes).
In addition to the items above, could you please comment on the four conclusions Dave
has listed at the bottom of page 4. Also, do you see anything in the lab results from
Dave that is cause for alarm? Anything that is contrary to your current understanding of
the landfill? Anything that suggests our monitoring program is inadequate?
The conceptual model for the site has previously characterized groundwater discharging
from perched flow zones on the hillside and from the regional and bedrock flow zones
beneath Powell River. Therefore, it is not surprising that additional springs have been
identified along the hill slope. The intent of the groundwater monitoring program is to
monitor groundwater conditions from representative flow zones at select locations
downgradient of the site; obviously, it is not expected that groundwater monitoring
would be undertaken at each and every location where groundwater discharge occurs
along the hillside.
Sampling from springs can be problematic because the inherent incorporation of silt
particles in the samples can cause anomalous concentrations of totals metals and other
organic constituents. In these instances, it would be prudent to sample for dissolved
metals analysis on samples that are filtered and acidified in the field so the potential
effect of the sediment content on the sample results can be can be removed.
Leachate from the Wildwood Landfill is characterized by a high pH and high
concentrations of specific conductance, sulphate and total organic carbon. In the
Environmental Assessment, elevated chloride was also identified as a good “tracer” of
landfill leachate, due to its conservative nature along the groundwater flow path. These
constituents are not elevated in the results of the spring sampling conducted by the third
parties.
It should also be noted that Golder has not conducted a site reconnaissance to verify
that the sampling locations are in fact springs (i.e. locations where groundwater
discharges to ground surface). It may be possible that the sampling locations represent
surface water courses.
Finally, I wanted to share with you a comment from MOE. They indicated that Liz is
looking forward to seeing the 2010 report, especially in regard to a recommendation that
were made in the 2009 report regarding specific conductivity in a well near Harris’ midslope well. Perhaps you could have a look at this information from 2010. Is there a well
near there that has shown an upward trend? If so, which way did it trend in 2010?
We have just received the final results of the wet season monitoring program and are
reducing the data, so we need a little more time before we can give a full report.
However, we can say that no detectable dioxins were found upgradient at 93-2B and
06-2L, nor at the Spring S1, 94-16L, 94-16B, 94-1/3 or the pumping well 99-5.
Consistent with previous years, detectable concentrations were found at 89-5, AH3 and
AH-6L, together with low levels at the Mill Filterhouse. No detectable levels of PCBs
were found.
In 2009, we had observed an increasing trend in specific conductivity at AH6L and a
slight increase in conductivity in the perched flow zones at snap shot sampling wells 9419. In 2010, the conductivity at AH6L returned to previous levels while the
conductivities at 94-19 remained consistent or slightly lower than the previous year. In
accordance with the recommendation from our 2009 report, we collected a sample from
snap-shot sampling well 94-19L for a full suite of laboratory analysis in December.
None of the dissolved metals were above the CSR at this location (vanadium was just
above the BCWQG for reference purposes only). Detectable levels of dioxins were
found (0.00342 pg/L OCDD).