HEALTH CONSULTATION
BASS LAKE DUMP
ST. LOUIS PARK, HENNEPIN COUNTY, MINNESOTA
I. SUMMARY OF BACKGROUND AND HISTORY
The Minnesota Department of Health (MDH) received a request from the Minnesota Pollution Control Agency (MPCA) to evaluate potential public health concerns regarding the Bass Lake Dump, located in the city of St. Louis Park, Hennepin County, Minnesota (the site). The site was identified by the MPCA through its Dump Assessment Program as an "action site", indicating that the site warranted further evaluation because of its potential to adversely impact public health or the environment. This health consultation is based on a site visit conducted by MDH staff on June 7, 2002, and on information provided to MDH by the MPCA and its consultant, STS Consultants, LTD (STS; STS 2002, STS 2003).
The site is located in the northeast quadrant of the intersection of Monterrey Drive and Beltline Boulevard in St. Louis Park. The dump itself is in a former wetland area that has been converted into parkland. The parkland is owned by the city of St. Louis Park. The site location is shown in Figure 1, and a site map is presented in Figure 2. The dump area occupies approximately 5.5 acres; it is mostly covered with grass playing fields and tennis courts, although the eastern edge of the dump is undeveloped and partially wooded, with small wetland areas. A community garden was also observed on the site during a site visit by MDH staff (see below).
The dump began accepting wastes in the early 1960s, and it was operated as a dump until about 1969. The dump primarily accepted ash from a city-operated incinerator, but it also received general rubbish at times as well. A 1968 inspection report indicates that the waste was covered weekly and that non-combustible wastes, garbage, dead animals, and other debris were not accepted (STS 2002). Total tonnage was estimated at 4,368 tons per year. The report also indicates, however, that at least once per year rubbish from a city wide collection was brought to the site and burned. The area immediately surrounding the site is largely commercial, residential, and parkland. The nearest homes are located approximately ¼ to ½ mile to the south and east.
Only small amounts of waste are currently exposed at the surface of the dump as a result of erosion of the cover along the eastern side. On the basis of a Phase II site investigation conducted by STS, the estimate of the volume of waste and fill soils at the site is approximately 70,000 cubic yards (STS 2003).
Geology/Hydrogeology
Available geologic information provided by STS indicates that soils at the site are composed primarily of "organic deposits, drained and filled" lying over peat and outwash sands (STS 2002). The uppermost bedrock is the Prairie du Chien limestone, which would be expected to be found at depths of approximately 50 to 100 feet below grade. Six test trenches dug at the site in 1996 confirmed the presence of wastes materials (primarily ash) at depths of up to 13 feet. Soil borings conducted by STS also confirm the presence of up to 17.5 feet of fill material and wastes overlying native soils (STS 2003). The location of the test trenches and borings is illustrated in Figure 2. A cross section of the dump prepared by STS (and its location) is presented in Figures 3 and 4.
The surficial groundwater is expected to flow east towards local wetlands, Bass Lake, and Lake Calhoun. Surficial groundwater was encountered in the 1996 test trenches and in most of the borings drilled by STS at the site at depths of 8 to 11.5 feet below ground. Waste materials were in many cases found below the surficial water table. Groundwater in the deeper Prairie du Chien formation is contaminated as a result of the nearby Reilly Tar Superfund site (a state and federal Superfund site).
On June 7, 2002, MDH staff visited the Bass Lake dump site. The site is located in Wolfe Park at the corner of Monterrey and Beltline Road in the city of St. Louis Park. At the time of the site visit, the dump was a city park, with open fields, a walking path, tennis courts, and a community garden. The outline of the dump itself is more or less defined by city streets on the west and south and by wetlands to the north and east. There is a drop- off on the east side, towards wetlands, where some wastes are exposed. For the most part, the dump appears to be well covered.
Small amounts of wastes were observed protruding from the soil along the wooded east edge of the dump, including asphalt, concrete, glass, and slag. There are several erosion gullies where the wastes are especially visible, although wastes can be seen all along the eastern slope of the dump. The area here is thick with underbrush, although signs of use such as cans, bottles, and a small campsite were apparent. Some wastes, such as asphalt chunks and at least one small piece of slag, were observed in the community garden area on the northwest corner of the dump.
The surrounding land use is mainly commercial and recreational. The closest homes are to the south and east, across Excelsior Boulevard. A few homes in this area may use private wells, according to state records, but they are located some distance from the site and are unlikely to have been impacted by the dump. Several commercial wells are near the site, mainly to the north and west. Groundwater from the site likely discharges east into the adjoining wetlands. There is a shallow monitoring well on the southwest corner of the dump, related to the nearby Reilly Tar Superfund site.
Site Investigation
Six test trenches were dug at the site by STS in 1996 for geotechnical purposes identified fill and waste materials at the site. In 2002, eight soil borings were advanced by STS at the site by use of a hollow-stem auger. The boring locations are shown in Figure 2. The borings encountered a layer of sand to silty clay cover soils overlying up to 17.5 feet of fill and waste materials. This layer in turn overlies native organic silts and outwash sands. Solid wastes encountered included wood, metal, concrete, coal cinders, plastic, and glass. Organic vapor measurements were collected by use of a photo ionization detector (PID) during drilling. Organic vapors were found above a concentration of 5 PID units, which is considered a background level, in one boring. An organic vapor concentration of 8 PID units was found in boring B-3 at a depth of 2.5 to 7.5 feet below grade. Methane gas was also measured, but it was not detected in any of the borings.
Soil and Waste Samples
Surface soil samples were collected from five locations at the site. The first two samples were analyzed for metals, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), diesel range organics (DRO), pesticides, and herbicides. The last three samples, which were collected in a community garden, were analyzed for metals, PCBs, and PAHs only. Several metals, PAHs, pesticides, and one PCB were detected in the samples. Levels of two metals, arsenic and chromium, exceeded the applicable MPCA soil screening criteria for the protection of human health or groundwater quality in two samples (MPCA 2003). These criteria are known as Soil Reference Values (SRVs) and Soil Leaching Values (SLVs). The SRV represents the concentration of a contaminant in the soil below which normal dermal contact, inhalation, and/or ingestion does not represent a human health risk. Because the site is located in a park, the most recent SRVs for recreational land use were used for comparison. The SLV represents the concentration of a contaminant in soil above which the contaminant is able to leach into the groundwater at levels in excess of drinking water standards. The surface soil analytical results are presented in Table 1. It should be noted that the chromium results in soil were for total chromium, while the SRV and SLV are for hexavalent chromium. This form of chromium is more toxic, but much less common in the environment. The screening criteria for hexavalent chromium are used, however, for the sake of conservatism.
Four samples of waste materials from individual borings (plus one duplicate), and one composite sample of the waste materials (plus one duplicate) were collected from depths of 8 to 10 feet below grade. The individual boring samples were analyzed for volatile organic compounds (VOCs), while the composite sample was analyzed for metals, DRO, PCBs, PAHs, pesticides, and herbicides. No VOCs were detected in the individual boring samples, and DRO, PAHs, pesticides, and herbicides were not detected in the composite sample. Low levels of PCBs were found in the composite sample. Levels of some metals exceeded SRVs and/or SLVs in the composite sample, including chromium, copper, lead, and selenium. The results of the waste samples are presented in Table 2.
Three samples of soil from beneath the waste materials (plus one duplicate) were collected to determine if contaminants had leached from the waste materials down into the native soils. Each sample was analyzed for VOCs, metals, DRO, PCBs, PAHs, pesticides, and herbicides. The sample results are shown in Table 3. No VOCs, PCBs, PAHs, pesticides, or herbicides were detected in these samples. Low levels of metals and DRO were detected, with levels of arsenic and chromium slightly exceeding their SRV or SLV in two of the three samples.
Sediment
Two sediment samples (plus one duplicate) were collected from wetlands east and north of the dump. The sediment sample locations are shown in Figure 2. The samples were analyzed for metals, PCBs, PAHs, and pesticides. Elevated levels of metals (especially copper, cadmium, and lead) were detected in the sediment samples. Many of the metals were found to exceed MPCA sediment evaluation criteria, with concentrations of lead being especially high. PCBs were also detected and found to exceed the sediment evaluation criterion. The sediment sample analysis results can be found in Table 4.
Surface Water
One sample (plus one duplicate) of surface water was collected from the pond located on the eastern edge of the dump. The sample was analyzed for metals, DRO, PAHs, PCBs, pesticides, and herbicides. Four metals (arsenic, barium, copper, and manganese) and DRO were detected in the sample, with the concentrations of copper and DRO exceeding their surface water quality chronic standard for Class 2B waters, the applicable standards for this type of water body. The surface water sample results are presented in Table 5.
Groundwater
Groundwater samples were collected from six soil borings (with one duplicate) and were analyzed for VOCs, metals, PCBs, PAHs, DRO, pesticides, and herbicides. A groundwater sample was also collected from a permanent monitoring well located on the southwest corner of the site. The location of this well is visible in Figure 2; it was installed to monitor contamination in the regional aquifer from the nearby Reilly Tar Superfund site. The results of the groundwater samples are presented in Table 6.
VOCs were detected in two of the groundwater samples, from borings B-1 and B-2. The VOCs detected include acetone, ethyl ether, methyl ethyl ketone, and naphthalene. None were detected at concentrations approaching their respective MDH Health Risk Limits (HRLs) for private drinking water supplies. Two of the VOCs, acetone and methyl ethyl ketone, were also detected at similar concentrations in the field blank, indicating that their presence in the samples may be a result of laboratory contamination.
DRO was detected in four of the six samples. The concentrations of DRO ranged from 150 micrograms per liter (µg/L) in boring B-5 to 1,800 µg/L in boring B-1. Three of the four samples exceeded the MDH Health-Based Value (HBV) for DRO in drinking water of 200 µg/L. DRO was also found in the field blank at a concentration of 130 µg/L, so the results may not be entirely accurate. Two herbicides (acetochlor and prometon) and one pesticide (endosulfan) were found in the groundwater sample from boring B-1, with the concentration of acetochlor exceeding its HBV. The HRLs and HBVs represent levels of contamination in private drinking water supplies that MDH considers safe for daily human consumption over a lifetime. The HRLs have been promulgated into rule, while the HBV's have not.
No PAHs or PCBs were found in the groundwater samples, and concentrations of metals were below detection limits or within background ranges with the exception of arsenic and manganese. Arsenic was found in five of the six samples at concentrations as high as 71.7 µg/L. There is no HRL for arsenic; the proposed federal Maximum Contaminant Limit (MCL) for public water supplies for arsenic is 10 µg/L. Manganese exceeded the MDH HBV of 1,000 µg/L in the sample from boring B-3.
No contaminants were detected in the permanent monitoring well, and concentrations of metals were within background ranges.
Unpermitted or abandoned solid waste dump sites may pose a potential human health risk when waste products or chemicals that were disposed at the site are present in exposed soil, groundwater, surface water, or air at levels of potential health concern. Waste materials in old dumps are often buried beneath a shallow layer of whatever type of soil is easily available at the time. Often, the cover materials are thin or absent in spots, exposing wastes and contaminants. There are also potential health risks when people are exposed to physical hazards such as sharp objects, pits, or holes that result from uneven settling, or steep grades that may result from improper closure or maintenance of the site. For actual health risks or adverse health effects to occur, both the chemicals (or hazards) must be present and people must come into contact with them.
Soil/Wastes
The majority of the Bass Lake Dump site is well covered and vegetated, with erosion exposing wastes only at the eastern edges of the dump. The results of laboratory analysis of surface soil samples showed elevated levels of arsenic and pesticides in two samples, one of which (S-2) was collected from the open playing field. The concentration of arsenic exceeded the MPCA recreational SRV of 12 milligrams per kilogram of soil (mg/kg). It is difficult to determine, however, how often the fields are used by individual people or groups, so that the amount of potential human exposure is unknown. Since most of the site is covered and vegetated, frequent exposure is not expected. While concentrations of arsenic were below laboratory detection limits in the community garden area, only three samples were collected, and the presence of arsenic or other metals at levels of potential concern cannot be ruled out. Arsenic is capable of being taken up at low levels in plants grown for human consumption (ATSDR 2000). Low levels of PCBs were also detected in one sample collected in the community garden area. For this reason, MDH verbally recommended that the city of St. Louis Park not use the site for a community garden again this year, and the city has confirmed that it will no longer be used as such (personal communication with C. Walsh, City of St. Louis Park, May 9, 2003). Because the frequency of contact with the contaminated soils is unclear, the human health risk from contact with exposed contaminated soils or physical hazards is difficult to estimate.
Organic waste materials in a dump (if it was not burned regularly) often degrade and generate methane and other gases. Low levels of chemical solvents may also be present in gas produced by old dumps. Together, these gases are referred to as "landfill gases." These frequently gases can migrate up to a few hundred feet from the dump site, depending on local conditions. This gas migration can result in explosive levels of methane and concentrations of solvents above health concerns in nearby homes or buildings. However, methane gas was not detected in any of the borings at the site, and the fact that the majority of wastes deposited at the site consisted of incinerator ash indicates that methane gas is likely not being generated in large quantities within the waste.
Composite samples of the buried waste material itself showed elevated concentrations of metals, with concentrations of copper, lead, and selenium exceeding their SRVs or SLVs. Low levels of PCBs were also detected in the waste samples. People are unlikely to come into contact with the buried waste materials, however, unless the materials are excavated or disturbed. This type of activity should not be occurring on a regular basis, given the fact that the site is used as a public park. Workers who need to excavate at the site for utilities, landscaping, or other purposes should be notified of the presence of waste materials. A formal notice filed with the property deed would also alert any future landowners to the presence of a dump. The frequency of exposure to site soil is expected to be low.
Elevated concentrations of arsenic, copper, lead, and manganese, and low levels of DRO were found in soils samples collected beneath the waste deposit, indicating that the waste is capable of leaching at least some contaminants. Some of these metals were also detected in samples of groundwater.
Groundwater
The degradation of solid waste produces leachate when infiltrating water contacts the waste and dissolves chemicals from it. The SLVs attempt to measure the ability of the waste materials or contaminated soil to produce leachate. Leachate may discharge to surface water or infiltrate into groundwater. Groundwater contaminated by leachate usually does not have any distinguishing appearance, color, or taste, and people are rarely aware of any problem unless the water is tested. As described, multiple contaminants were found in the waste materials at levels in excess of the SLVs. Arsenic, barium, and manganese were also found in groundwater at the site, indicating that they are leaching from soils or waste into the groundwater. Samples of soils beneath the wastes showing similar contamination support this conclusion. Manganese exceeded its HBV in one sample, and arsenic exceeded the proposed MCL in five of six samples.
Levels of DRO in excess of the MDH HBV were found in three of six samples collected from beneath and around the Bass Lake Dump. This finding indicates that petroleum products were likely disposed at the site and have leached from the waste materials and reached the uppermost groundwater. Several pesticides and herbicides were also detected in groundwater, with levels of one herbicide exceeding its HRL.
The data indicate that an area of groundwater contamination exists beneath and around the dump. The extent of the contamination in groundwater is not known, because the scope of the investigation was limited to the area immediately on and around the dump. The main types of contaminants detected at levels of concern (i.e. metals and DRO) typically do not migrate great distances in groundwater, however. Humans are unlikely to drink the contaminated groundwater, because the site is in a fully developed part of the Twin Cities area and no potable water supply wells are located within approximately ¼ mile of the site in the suspected down-gradient direction. In addition, the shallow groundwater likely discharges into the nearby wetlands or lakes. A groundwater sample from the regional aquifer below the site did not show evidence of contamination from the dump. Therefore, no exposure via groundwater is expected from this site.
Surface Water and Sediment
A surface water sample showed levels of copper and DRO in excess of chronic standards. While not a human health concern, copper is very toxic to certain aquatic organisms. Other metals were detected at lower concentrations.
Two sediment samples showed relatively high levels of metals in both samples and PCBs in one sample. These concentrations were well above their sediment screening criteria (which are designed to be protective of aquatic organisms), but they also approach the recreational SRVs for the protection of human health, a fact that indicates that frequent human contact with the contaminated sediments could pose an elevated health risk. Given the fact that the wetlands are relatively isolated and not attractive for recreation, significant human contact is unlikely to occur.
The contaminants may be entering the wetlands through the discharge of contaminated groundwater, through the runoff of rain and snow over exposed wastes or contaminated soils near the wetlands, or perhaps through the discharge of storm water from nearby roads. The nature of the contaminants, especially DRO, suggestss that at least some of the contaminants may be the result of runoff from roads and parking lots.
Child Health Considerations
Some unique vulnerabilities of infants and children that make them of special concern to communities faced with contamination of their water, soil, air, or food. Children are at greater risk than adults from certain kinds of exposures to hazardous substances at waste disposal sites. They are more likely to be exposed because they play outdoors and they often bring food into contaminated areas. They are smaller than adults and therefore breathe dust, soil, and heavy vapors close to the ground. Children also weigh less, resulting in higher doses of chemical exposure per body weight. In addition, the developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care.
While the dump is located in a park used by children, significant contact with exposed contaminated soils and waste materials does not appear to be frequent. Children are not exposed to the contaminated groundwater, and they are unlikely to use the wetlands for recreation.
The Bass Lake Dump is a somewhat unusual town dump in that it appears that incinerator ash was the main type of waste it received. Large items such as scrap metal, appliances, or building demolition wastes were not disposed there. The site is fairly well covered and graded, and as a result physical hazards are minimal. In terms of contaminants, the ash/waste material appears to contain primarily heavy metals and petroleum products, which are leaching into the groundwater. The extent of the groundwater contamination is not known, but it is not likely to be extensive. The site, as it exists today, presents no apparent public health hazard because significant exposure is not observed to be occurring. However, contamination is present in soil, waste materials, groundwater, and sediments above levels of potential health concern. The contaminated sediments in the wetlands may represent a risk to aquatic life.
MDH's Public Health Action Plan for the site will consist of:
Agency for Toxic Substances and Disease Registry. Toxicological profile for arsenic. Atlanta: US Department of Health and Human Services;;2000 Sept.
Minnesota Pollution Control Agency. Risk-based site evaluation guidance
documents. St. Paul, Minnesota: 2003 Jan.
Available online at: http://www.pca.state.mn.us/cleanup/riskbasedoc.html 
STS Consultants LTD. Draft Phase I environmental site assessment, Bass Lake Dump. 2002 Apr. 16.
STS Consultants LTD. Phase II environmental site assessment, Bass Lake Dump. 2003 May 1.
James Kelly
Health Assessor
Site Assessment and Consultation Unit
Minnesota Department of Health
tel: (651) 215-0913
Ginny Yingling
Hydrologist
Site Assessment and Consultation Unit
Minnesota Department of Health
tel: (651) 215-0917
This Bass Lake Dump Health Consultation was prepared by the Minnesota Department of Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health consultation was begun.
Alan W. Yarbrough
Technical Project Officer, SPS, SSAB, DHAC, ATSDR
The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health consultation and concurs with the findings.
Sven E. Rodenbeck
for Richard Gillig
Chief, State Programs Section, Superfund Site Assessment Branch, DHAC, ATSDR
Figure 1. Bass Lake Dump Site Location
Figure 3. Cross-Section Location
TABLE 1. Surface Soil Sample Analytical
Results
Bass Lake Dump
Concentrations in mg/kg
| Phase I ESA Sample #1 | Phase I ESA Sample #2 | SS-1 (garden area) | SS-2 (garden area) | SS-3 (garden area) | SLV | SRV | |
| Volatile Organics Compounds - VOCs EPA 8260 Methanol Extraction | (samples not analyzed for this parameter) | ||||||
| Diesel Range Organics - DRO | ND | ND | - - | - - | - - | NE | NE |
| Metals EPA 6010 | (only metals detected are shown) | varies | varies | ||||
| Arsenic | 33.5 | 20.9 | ND | ND | ND | 15.1 | 12 |
| Barium | 154 | 73.8 | 77.1 | 118 | 91.6 | 842 | 1200 |
| Cadmium | 1.7 | 1.82 | 0.337 | ND | 0.297 | 4.4 | 40 |
| Chromium* | 56.3 | ND | 18 | 15.3 | 13.0 | 18** | 80 |
| Copper | 61.5 | 27.9 | 17.3 | 14.9 | 16.1 | 400 | 100 |
| Lead | 120 | 24.4 | 59.3 | 35.6 | 44.0 | 525 | 400 |
| Mercury | 0.0499 | 0.0433 | 0.116 | 0.0541 | 0.0475 | 1.6 | 1.5 |
| Manganese | - - | - - | 348 | 537 | 413 | NE | 1800 |
| Nickel | ND | ND | 15.3 | 14.6 | 13.2 | 88 | 550 |
| Polychlorinated Biphenyls - PCBs EPA 8082 | (only compounds detected are shown) | 2.1 | 1.4 | ||||
| Aroclor 1254 | 0.14 | ND | 0.29 | ND | ND | 2.1 | 1.4 |
| Polyaromatic Hydrocarbons - PAHs EPA 8270 | (only compounds detected are shown) | varies | varies | ||||
| Phenenthrene | 4.5 | ND | ND | ND | ND | NE | NE |
| Fluoranthene | 4.0 | ND | ND | ND | ND | 295 | 1290 |
| Pyrene | 4.2 | ND | ND | ND | ND | 272 | 1060 |
| Benzo(a)anthracene | 2.2 | ND | ND | ND | ND | NE | NE |
| Chrysene | 2.2 | ND | ND | ND | ND | NE | NE |
| Benzo(b)fluoranthene | 2.3 | ND | ND | ND | ND | NE | NE |
| Benzo(k)fluoranthene | 2.4 | ND | ND | ND | ND | NE | NE |
| Indeno(1,2,3-cd)pyrene | 2.4 | ND | ND | ND | ND | NE | NE |
| Benzo(g,h,i)perylene | 2.2 | ND | ND | ND | ND | NE | NE |
| Total Carcinogenic PAHs as BaP | 0.95 | ND | ND | ND | ND | 10.2 | 2 |
| Pesticides EPA 8081 | (only compounds detected are listed) | (these samples not analyzed for this parameter not analyzed) | varies | varies | |||
| Heptachlor epoxide | ND | 0.0025 | - - | - - | - - | NE | 0.5 |
| 4,4"-DDT | 0.018 | 0.0081 | - - | - - | - - | NE | 18 |
| alpha-Chlordane | 0.003 | ND | - - | - - | - - | NE | 16 |
| Herbicides (MDA List 1) | No detects for all compounds | (these samples not analyzed for this parameter not analyzed) | varies | varies | |||
* = denotes value for total chromium (chromium (III) + chromium
(VI))
** = SLV for chromium VI
- - = Sample not analyzed for this parameter.
ND = Not Detected above Laboratory Detection Limit.
SLV = MPCA Soil Leaching Value
SRV = MPCA Soil Reference Value (recreational)
NE = Not Established
Bold = Concentration above detection limits
| = Concentration exceeds SRV | |
| = Concentration exceeds SLV |
Source: STS 2003
TABLE 2. Waste Sample Analytical Results
Bass Lake Dump
Concentrations in mg/kg
| B-1 (10 ft.) |
B-2 (8 ft.) |
B-3 (7 ft.) |
B-8 (10 ft) | B-15 (8 ft.) Duplicate of B-2 | Waste Composite-1 | Waste Composite-2 (Duplicate of Waste Comp.-1) | Trip Blank | SLV | SRV | |
| Volatile Organics Compounds - VOCs EPA 8260 Methanol Extraction | No detects for all compounds analyzed | (these samples were not analyzed for VOCs) | No Detects | varies | varies | |||||
| Diesel Range Organics - DRO | (These samples not analyzed for DRO) | <99 | <99 | (not analyzed for DRO) | NE | NE | ||||
| Metals EPA 6010 | (These samples not analyzed for metals) | (only metals detected are shown) | (not analyzed for metals) | varies | varies | |||||
| Barium | - - | - - | - - | - - | - - | 156.0 | 205 | - - | 842 | 1200 |
| Cadmium | - - | - - | - - | - - | - - | 1.05 | 0.87 | - - | 4.4 | 40 |
| Chromium* | - - | - - | - - | - - | - - | 36.6 | 29.0 | - - | 18 | 80 |
| Copper | - - | - - | - - | - - | - - | 305.0 | 180.0 | - - | 400 | 100 |
| Lead | - - | - - | - - | - - | - - | 703 | 283 | - - | 525 | 400 |
| Mangnaese | - - | - - | - - | - - | - - | 778 | 597 | - - | NE | 1800 |
| Mercury | - - | - - | - - | - - | - - | 0.161 | 0.083 | - - | 1.6 | 1.5 |
| Nickel | - - | - - | - - | - - | - - | 65 | 35.2 | - - | 88 | 550 |
| Selenium | - - | - - | - - | - - | - - | 29.0 | 20.3 | - - | 1.5 | 200 |
| Polychlorinated Biphenyls - PCBs EPA 8082 | (these samples not analyzed for PCBs) | (only PCBs detected are shown) | (not analyzed for PCBs) | 2.1 | 1.4 | |||||
| Aroclor 1254 | - - | - - | - - | - - | - - | 0.054 | 0.04 | - - | 2.1 | 1.4 |
| Aroclor 1260 | - - | - - | - - | - - | - - | <0.019 | 0.024 | - - | 2.1 | 1.4 |
| Polyaromatic Hydrocarbons - PAHs EPA 8270 | (these samples not analyzed for PAHs) | No detects for all compounds analyzed | (not analyzed for PAHs) | varies | varies | |||||
| Pesticides EPA 8081 | (these samples not analyzed for pesticides) | No detects for all compounds analyzed | (not analyzed for pesticides) | varies | varies | |||||
| Herbicides (MDA List 1) | (these samples not analyzed for herbicides) | No detects for all compounds analyzed | (not analyzed for herbicides) | varies | varies | |||||
* = denotes value for total chromium (chromium (III) + chromium (VI))
- = compound not analyzed.
SLV = MPCA Soil Leaching Value
SRV = MPCA Soil Reference Value (recreational)
ND = Not Detected
NE = Not Established
Bold = Concentration above detection limits
| = Concentration exceeds SRV | |
| = Concentration exceeds SLV |
Source: STS 2003
TABLE 3. Soil Below Waste Sample Analytical
Results
Bass Lake Dump
Concentrations in mg/kg
| B-1 (18 ft.) |
B-2 (15 ft.) |
B-3 (11 ft.) |
B-15 (15 ft) Duplicate of B-2 | Trip Blank | SLV | SRV | |
| Volatile Organics Compounds - VOCs EPA 8260 Methanol | No detects for all compounds analyzed | varies | varies | ||||
| Diesel Range Organics - DRO | 53 | 31 | <9.7 | 36 | (not analyzed for DRO) | NE | NE |
| Metals EPA 6010 | (only metals detected are listed) | (not analyzed for metals) | varies | varies | |||
| Arsenic | 14 | 12.5 | <2.62 | 10.9 | - - | 15.1 | 12 |
| Barium | 164 | 138 | 22.2 | 134 | - - | 842 | 1200 |
| Chromium* | 19.2 | 10.2 | 13.1 | 8.75 | - - | 18 | 80 |
| Copper | 28.3 | 25.5 | 8.52 | 15.6 | - - | 400 | 100 |
| Lead | 45.6 | 31.8 | 4.81 | 6.7 | - - | 525 | 400 |
| Manganese | 329 | 341 | 94.6 | 317 | -- | NE | 1800 |
| Nickel | <20.1 | <15 | 11.8 | <14.1 | - - | 88 | 550 |
| Polychlorinated Biphenyls - PCBs EPA 8082 | No detects for all compounds analyzed | (not analyzed for PCBs) | 2.1 | 1.4 | |||
| Polyaromatic Hydrocarbons - PAHs EPA 8270 | No detects for all compounds analyzed | (not analyzed for PAHs) | varies | varies | |||
| Pesticides EPA 8081 | No detects for all compounds analyzed | (not analyzed for pesticides) | NE | varies | |||
| Herbicides (MDA List 1) | No detects for all compounds analyzed | (not analyzed for herbicides) | varies | varies | |||
* = denotes value for total chromium (chromium (III) + chromium (VI))
- - = compound not analyzed.
SLV = MPCA Soil Leaching Value
SRV = MPCA Soil Reference Value (recreational)
NE = Not Established
Bold = Concentration above detection limits
| = Concentration exceeds SRV | |
| = Concentration exceeds SLV |
Source: STS 2003
TABLE 4. Sediment Sample Analytical Results
Bass Lake Dump
Concentrations in mg/kg
| SD-1 East Dump Area (pond) |
SD-2 North Dump Area (pond) |
SD-3 Duplicate of SD-1 | LEL or ERL | SQC or SQB | |
| Metals EPA 6010 | (only metals detected are listed) | varies | varies | ||
| Barium | 127 | 163 | 132 | NE | NE |
| Cadmium | 1.63 | 3.3 | 2.22 | 0.6 | NE |
| Chromium* | 42.8 | 75.7 | 47.6 | 26 | NE |
| Copper | 69.7 | 110 | 78.1 | 16 | NE |
| Lead | 323 | 331 | 442 | 31 | NE |
| Mercury | 0.168 | 0.218 | 0.2 | 0.2 | NE |
| Mangenese | 724 | 371 | 720 | 460 | NE |
| Nickel | 21.9 | 66.5 | 23.1 | 16 | NE |
| Polychlorinated Biphenyls - PCBs EPA 8082 | (only PCBs detected are listed) | varies | varies | ||
| Aroclor 1254 | 0.11 | ND | 0.12 | 0.06 | NE |
| Aroclor 1260 | 0.055 | ND | 0.056 | 0.005 | NE |
| Total PCBs | 0.165 | ND | 0.176 | 0.07 | 0.0018 |
| Polyaromatic Hydrocarbons - PAHs EPA 8270 | No detects for all compounds analyzed | varies | varies | ||
| Pesticides EPA 8081 | No detects for all compounds analyzed | varies | varies | ||
* = denotes value for total chromium (chromium (III) + chromium (VI))
LEL = Lowest Effect Level
ERL = Effects Range Low Value
SQC = Sediment Quality Criteria
SQB = Sediment Quality Benchmark
ND = Not detected above Laboratory Detection Limit
Bold = Concentration above detection limits
| = Concentration exceeds SQC/SQB | |
| = Concentration exceeds LEL/ERL |
Source: STS 2003
TABLE 5. Surface Water Sample Analytical
Results
Bass Lake Dump
Concentrations in mg/L
| SW-1 | SW-2 (Duplicate of SW-1) | Chronic Standard1 | |
| Diesel Range Organics - DRO | 0.30 | 3.50 | 0.20 |
| Metals EPA 6010 * | (only metals detected are shown) | varies | |
| Arsenic | 0.0111 | ND | 0.053 |
| Barium | 0.129 | 0.129 | NE |
| Copper | 0.014 | 0.014 | 0.0064 |
| Manganese | 0.135 | 0.136 | NE |
| Polychlorinated Biphenyls - PCBs EPA 8082 | No detects for all compounds analyzed. | 0.000029 | |
| Polyaromatic Hydrocarbons - PAHs EPA 8270 | No detects for all compounds analyzed. | varies | |
| Pesticides EPA 8081 | No detects for all compounds analyzed. | varies | |
| Herbicides (MDA List 1) | No detects for all compounds analyzed. | varies | |
* = samples were filtered - the results represent dissolved
metal concentrations
(1) Standard for Class 2B Surface Water, Minnesota Rules 7050.0220, Subp. 5;
chronic standard.
NE = Standard not established.
ND = Not detected at concentration above Laboratory Detection Limit.
Bold = Concentration above detection limits
| = Concentration exceeds chronic standard |
Source: STS 2003
TABLE 6. Groundwater Sample Analytical Results
Bass Lake Dump
Concentrations in ug/l
| B-1 W-2 |
B-2 W-3 |
B-3 W-5 |
B-4 W-6 |
B-5 W-7 |
B-7 W-1 |
B-15 W-4 (duplicate of B-2) |
OW-1 (USGS Observation Well) | Field Blank | Trip Blank | Standard | Source | |
| Volatile Organics Compounds - VOCs EPA 465E | (only compounds detected are listed) | varies | varies | |||||||||
| Acetone | 6.8 | ND | ND | ND | ND | ND | ND | ND | 12 | ND | 700 | HRL |
| Ethyl Ether | 20.0 | ND | ND | ND | ND | ND | ND | ND | ND | ND | 1000 | HRL |
| Methyl Ethyl Ketone (MEK) | ND | 5.2 | ND | ND | ND | ND | ND | ND | 5.3 | ND | 4000 | HRL |
| Naphthalene | 6.0 | ND | ND | ND | ND | ND | ND | ND | ND | ND | 300 | HRL |
| Diesel Range Organics - DRO | 1,800 | 480 | ND | ND | 150 | 210 | 800 | ND | 130 | - - | 200 | HBV |
| Metals EPA 6010 ** | (only metals detected are listed) | varies | varies | |||||||||
| Arsenic | 71.7 | ND | 50.3 | 49.7 | 21.2 | 48.2 | 27.1 | ND | ND | - - | 10 | MCL* |
| Barium | 657 | 454 | 98.8 | 143 | 210 | 142 | 422 | 176 | ND | - - | 2,000 | HRL |
| Manganese | -- | -- | 1190 | 782 | 398 | -- | 348 | 544 | ND | - - | 1,000 | HBV |
| Polychlorinated Biphenyls - PCBs EPA 8082 | No detects for all compounds analyzed | - - | 0.04 | HRL | ||||||||
| Polyaromatic Hydrocarbons - PAHs EPA 8270 | No detects for all compounds analyzed | - - | varies | varies | ||||||||
| Pesticides EPA 8081 | (only pesticides detected are listed) | varies | varies | |||||||||
| Endosulfan I | 0.16 | ND | ND | ND | ND | ND | ND | ND | ND | - - | 40 | HBV |
| Herbicides (MDA List 1) | (Only herbicides detected are listed) | varies | varies | |||||||||
| Acetochlor | 18 | ND | ND | ND | ND | ND | ND | ND | ND | - - | 10 | HBV |
| Prometon | 0.63 | ND | ND | ND | ND | ND | ND | ND | ND | - - | 100 | HRL |
NOTES:
- - = Not Analyzed
ND = Not detected at concentration above the laboratory limit of detection
HRL = Health Risk Limit for Groundwater, Minnesota Department of Health
MCL = EPA Maximum Contaminant Levels
HBV = Health Based Values, Minnesota Department of Health
NE = Not Established
* = Proposed MCL
Bold = Concentration above detection limits
| = Concentration exceeds standard (MCL/HRL/HBV) |
Source: STS 2003
