Figure 1 illustrates the location of the Site and Figure 2 illustrates the Site layout, including borehole locations.

Transcription

1 1.0 Introduction Stantec Consulting Ltd. (Stantec) was retained by Mr. John Doe, on behalf of The Client to conduct a Phase II Environmental Site Assessment (ESA) at a property located at 151 Main Street, Small Town, Saskatchewan (Site). Figure 1 illustrates the location of the Site and Figure 2 illustrates the Site layout, including borehole locations. 1.1 STUDY OBJECTIVES The primary purpose of this investigation was to test for the presence of residual phase hydrocarbons in the following locations: area surrounding the former underground storage tank (UST) and the area near the former above ground storage tank (AST). It was also necessary to determine if environmental impact from previous coal operations existed. The specific objectives of the investigation were as follows: Assess the residual phase hydrocarbons in soil, if any; Assess coal operations impact, if any; and Make recommendations for further work, if required. 1.2 SCOPE OF WORK To accomplish the study objectives, the following tasks were performed by Stantec: Drill nine boreholes; Collect soil samples for ambient headspace/soil vapour concentration measurements and laboratory analysis; Submit soil samples for laboratory analyses of benzene, toluene, ethylbenzene, xylenes (BTEX), total petroleum hydrocarbons (TPH) and lead; Submit a soil samples for analysis of carbon content; and Prepare a report summarizing the investigation.

2 2.0 Background 2.1 DESCRIPTION OF THE SITE The Site consists of one vacant two-story brick building with a steel sided building addition on the south side of the building. The interior of the building was inspected during the assessment. The building is constructed of concrete, brick and steel. Main Street is located to the north of the Site, Bill s Auto Sales is located to the west, an alley is located to the south, and Pete s Auto Parts is located to the east. 2.2 PREVIOUS WORK COMPLETED AT THE SITE Stantec completed a Phase I ESA of the Site (Stantec, 2001) in November 2001 which identified the following issues: The Henderson s Directory search listed the property as Acme Coal Company yards in 1913 and it is believed that the coal company used the property as a fuel storage yard. At the time of the inspection, no evidence of underground storage tanks or aboveground storage tanks was observed on the property. Former fuel islands and an AST have been identified in 1947, it is suspected that USTs existed at that time as well.

3 3.0 Field Program 3.1 BOREHOLE DRILLING AND SOIL SAMPLING A total of nine boreholes (BH101 to BH109) were drilled at the Site on 22 February The locations of the boreholes are shown in Figure 2. Prior to commencing the site work, a safety meeting was held that covered job safety planning checklists, equipment check lists, emergency information and work site hazards. Each utility company was notified to locate public utilities prior to drilling activities. Big Boring Ltd. of Saskatoon, Saskatchewan was retained by Stantec to provide the necessary equipment and personnel to drill the boreholes to the necessary depths. Using a truck mounted Brat 22 with solid stem augers, the boreholes were advanced in 0.75 m intervals. Soil samples were removed from the auger flytes, examined and the lithology logged. Borehole logs are presented in Appendix A. Soil samples collected for combustible soil vapour concentration measurements were placed in 500 ml jars filled one half full and sealed with foil lined lids. The soil samples were allowed to reach an ambient temperature of approximately 20 C, after which time the combustible soil vapour concentration (CSVC) that accumulated in the headspace of the jar was measured with a GasTechtor Model 1238ME, calibrated for hexane, set for no methane response. Soil samples collected for potential laboratory analysis were placed in 125 ml glass jars fitted with Teflon-lined screw down lids for each sampling interval. Sample jars were filled to reduce headspace, the lids were screwed down and the samples were labeled. Soil samples were retained in a cooler to moderate temperature fluctuations prior to delivery to the laboratory for analysis.

4 4.0 Laboratory Program 4.1 SOIL Selected soil samples were submitted on 23 February 2001 to Enviro-Test Laboratories (ETL) in Saskatoon, Saskatchewan, for analysis of BTEX and TPH. The TPH analysis is defined as the summation of total extractable hydrocarbon (TEH) and total volatile hydrocarbon (TVH). Selected soil samples were also analyzed for carbon. The following soil samples were submitted to ETL: m, m, m, m, m and m. Analytical results are presented in Section 5.0 and the original analytical reports have been attached in Appendix B.

5 5.0 Regulatory Framework 5.1 SOIL GUIDELINES The following guidelines were used for comparison purposes to evaluate soil conditions at the Site: Saskatchewan Environment and Resource Management (1995). Risk Based Corrective Actions for Petroleum Contaminated Sites, level II criteria for a clay-till soil. Canadian Environmental Quality (CEQ) guidelines (1999) Saskatchewan Environment and Resource Management Guidelines The 1995 SERM guidelines are risk based remediation levels for soil and groundwater at underground storage tank (UST) sites. The levels were developed for the inhalation and ingestion pathways in fine grained or coarse grained soils. Sensitivity levels referenced in the guidelines are for sites of high, moderate or low sensitivity which correspond to Level I, Level II and Level III guideline concentrations, respectively. Considering the industrial and commercial activities that occur in and around the Site and the existing exposure pathways to potentially sensitive receptors through vapour inhalation, BTEX and TPH impacts were assessed with respect to the 1995 SERM guidelines for a level II, clay-till soil (SERM Guidelines), within the Site Canadian Environmental Quality Guidelines The 1999 Canadian Environmental Quality (CEQ) guidelines are intended for generic use and do not apply to specific site conditions. The criteria are generally utilized as guidelines that will protect human and environmental health issues for specific uses at sites. No criteria for lead are included in the SERM Guidelines. As a result the CEQ soil guidelines (CEQ Guidelines) were used to assess potential soil impact. The use of the CEQ Guidelines at the Site are for comparison purposes with lead only and do not imply remediation criteria. The CEQ Guidelines have superceded the former 1991 Interim Canadian Council of Ministers of the Environment (CCME) guidelines (CCME, 1991).

6 6.0 Results 6.1 SITE GEOLOGY The surficial units at the Site are fill composed primarily of sand and gravel, with some clay, extending to approximately 2 m below ground level (mbgl). Underlying the fill is a unit of fine to medium grained sand, varying in thickness from 0.6 m to 1.6 m. Below the sand, a sandy clay till is encountered at an average depth of 2.8 mbgl. The till becomes unoxidized at an average depth of approximately 4.5 mbgl. Occasional discontinuous sand layers, varying in thickness from 0.2 m to 0.6 m are interbedded within the clay till. 6.2 SITE HYDROGEOLOGY During drilling, groundwater was encountered at depths varying from 3.6 mbgl to 5.2 mbgl. At a hydrocarbon impacted site, the highest CSVCs are typically measured slightly above the water table. Depth to groundwater at the Site would likely be approximately 3.8 mbgl, based on CSVC measurements and field observations. No monitoring wells were installed at the Site. 6.3 HYDROCARBONS Residual Phase Hydrocarbons Six soil samples collected from the Site were submitted for laboratory analyses and the results are listed in Table 6.1. Trace concentrations of BTEX were measured in two soil samples, BH104@3.75 m and BH109@3.3 m. The values measured for BTEX constituents were below SERM Guidelines. Detectable concentrations of TPH were measured in three soil samples. Total petroleum hydrocarbon concentrations of 431 mg/kg, 213 mg/kg and 929 mg/kg were reported for BH104@3.75 m, BH107@3.75 m and BH109@3.3 m, respectively. The reported values for TPH were below the SERM Guideline criteria of 4,000 mg/kg for a Level II, clay-till soil. Based on the analytical results and the gas chromatograph (GC) scans, the nature of the contamination is consistent with diesel fuel, with most of the contaminant being in the C 11 to C 32 carbon range.

7 TABLE 6.1 Laboratory Analyses Results - Soil Samples Parameter Detection Limit SERM Criteria (a) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) Soil Vapour Headspace Measurements (ppm) Benzene 0.01 <0.01 <0.01 <0.01 <0.01 <0.01 < Toluene 0.01 <0.01 <0.01 <0.01 <0.01 < Ethylbenzene 0.01 <0.01 <0.01 <0.01 <0.01 < Xylenes 0.03 < <0.03 <0.03 < Total Volatile 0.5 <0.5 4 <0.5 1 < Hydrocarbons Total Extractable 5 <5 427 <5 212 < Hydrocarbons Total Petroleum <5 431 <5 213 < ,000 Hydrocarbons (b) Lead a. Saskatchewan Environment and Resource Management (SERM), November Risk Based Corrective Actions for Petroleum Contaminated Sites, Level II Criteria for a Clay-till soil. Note: Criteria for lead is based on Canadian Environmental Quality Guidelines, 1999, soil criteria for commercial land use. b. Total Petroleum Hydrocarbons (TPH) = Total Volatiles + Total Extractables. ppm = parts per million. -- = no guidelines exist Gaseous Phase Hydrocarbons During the field investigation, 75 soil samples were collected for CSVC measurements. The maximum values are presented in Table 6.2. CSVCs were measured in the nine boreholes, at 0.75 m increments, and were recorded on the borehole logs. TABLE 6.2 Maximum Soil Vapour Headspace Measurements Borehole Depth Soil Type Combustible Vapours (mbgl) (ppm) BH Clay till 300 BH Clay till 275 BH Clay till 500 BH Clay till 770 BH Clay till 225 BH Fill 200 BH Clay till 400 BH Clay till 325 BH Clay till 375 mbgl = metres below ground level ppm = parts per million

8 Hydrocarbon odour and staining were noted in BH101, BH104, BH107 and BH109. The Gastech ME1238 responds primarily to the volatile components of hydrocarbon contamination, and as a result correlation between CSVCs and analytical results is usually poor on a site where the primary contaminant is diesel. The measured CSVCs varied from 125 ppm to 770 ppm, with the highest CVSC, 770 ppm, being measured in a sample from BH104 at 3.75 mbgl. Based on the analytical results, CSVCs of 300 ppm and lower represent background conditions Liquid Phase Hydrocarbons Liquid phase hydrocarbons were not encountered during drilling Dissolved Phase Hydrocarbons Groundwater samples were not collected during this investigation. 6.4 LEAD Six soil samples from the Site were submitted for laboratory analysis for lead, and the results are presented in Table 6.1. Detectable concentrations of lead, varying from 5.5 mg/kg to 8.9 mg/kg were measured in all six soil samples. All values measured were below the CEQ Guideline criteria of 260 mg/kg for a commercial land use. 6.5 COAL Analytical results from soils samples indicate that coal has not impacted subsurface soils or groundwater.

9 7.0 Conclusions and Recommendations 7.1 CONCLUSIONS Based on the results of the investigation, the conclusions are as follows: Petroleum hydrocarbon impacted soil, below SERM Guidelines and CEQ Guidelines, exists on the Site; and The coal has not impacted the site. 7.2 RECOMMENDATIONS Stantec makes the following recommendations: Petroleum hydrocarbon levels in the impacted soil are below SERM Criteria and CEQ Guidelines and this report should be forwarded to SERM for review. Coal has not impacted the Site, as such no further work in this area is required.

10 8.0 Limitations and Qualifications In conducting the investigation and rendering our conclusions, Stantec gives the benefit of its best judgment based on its experience and in accordance with generally accepted professional standards for this type of investigation. This report was submitted with the best information to date and on the information provided. The conclusions made within this report are a professional opinion, not a certification of the sites environmental condition, no other warranty, expressed or implied is made. This report has been prepared for the exclusive use of The Client for the purposes of assessing the current state of hydrocarbons that may be present at the subject property. Any use which a third party makes of this report, or any reliance on or decisions to be made on it, are the responsibility of such third parties. Stantec accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this report. Our conclusions are limited by the following: all boreholes were drilled as presented on Figure 2. the investigation was limited to those hydrocarbon parameters specifically outlined in this report. the subsurface investigation was based on borehole locations, and conditions may vary between boreholes.

11 9.0 References Energy, Mines, & Resources Canada Regina, Saskatchewan (75 I/15). Scale 1:50,000. Saskatchewan Research Council, Geology and Groundwater Resources of the Saskatoon Area, Map 77h. Saskatchewan Research Council, Surficial Geology Map of the Saskatoon Area, Map 79. Saskatchewan Environment and Resource Management, November Risk Based Corrective Actions for Petroleum Contaminated Sites. Stantec Consulting Ltd., February Phase I Environmental Site Assessment, John s Night Club, 151 Main Street, Small Town, Saskatchewan (Stantec file no: ). University of Saskatchewan Atlas of Saskatchewan. K. Fung (ed.), 336pp.

12 10.0 Stantec Quality Management Program This report, titled Phase II Environmental Site Assessment, John s Night Club, Small Town, Saskatchewan, prepared for The Client, 13 January 2002, was produced by Stantec Consulting Ltd. This report was written by the following individual: Billy Bob, E.I.T., B.Sc. Environmental Engineer Signature This report was reviewed by the following individual: Greg T. Saretzky, M.Sc., P.Eng. Geo-Environmental Engineer Signature

13 APPENDIX A Borehole Logs

14 Borehole 103

15 Borehole 104

16 Borehole 107