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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 about1969. The dump primarily accepted ash from a city-operated incinerator, but it also receivedgeneral rubbish at times as well. A 1968 inspection report indicates that the waste was coveredweekly and that non-combustible wastes, garbage, dead animals, and other debris were notaccepted (STS 2002). Total tonnage was estimated at 4,368 tons per year. The report alsoindicates, however, that at least once per year rubbish from a city wide collection was brought tothe site and burned. The area immediately surrounding the site is largely commercial,residential, and parkland. The nearest homes are located approximately to mile to the southand east.

Only small amounts of waste are currently exposed at the surface of the dump as a result oferosion of the cover along the eastern side. On the basis of a Phase II site investigationconducted 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 arecomposed 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 beexpected to be found at depths of approximately 50 to 100 feet below grade. Six test trenchesdug at the site in 1996 confirmed the presence of wastes materials (primarily ash) at depths of upto 13 feet. Soil borings conducted by STS also confirm the presence of up to 17.5 feet of fillmaterial and wastes overlying native soils (STS 2003). The location of the test trenches andborings 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 LakeCalhoun. Surficial groundwater was encountered in the 1996 test trenches and in most of theborings drilled by STS at the site at depths of 8 to 11.5 feet below ground. Waste materialswere in many cases found below the surficial water table. Groundwater in the deeper Prairie duChien formation is contaminated as a result of the nearby Reilly Tar Superfund site (a state andfederal Superfund site).

Site Visit

On June 7, 2002, MDH staff visited the Bass Lake dump site. The site is located in Wolfe Parkat the corner of Monterrey and Beltline Road in the city of St. Louis Park. At the time of the sitevisit, the dump was a city park, with open fields, a walking path, tennis courts, and a communitygarden. The outline of the dump itself is more or less defined by city streets on the west andsouth and by wetlands to the north and east. There is a drop- off on the east side, towardswetlands, where some wastes are exposed. For the most part, the dump appears to be wellcovered.

Small amounts of wastes were observed protruding from the soil along the wooded east edge ofthe dump, including asphalt, concrete, glass, and slag. There are several erosion gullieswhere the wastes are especially visible, although wastes can be seen all along the eastern slopeof 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 smallpiece 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 thesouth 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 tohave been impacted by the dump. Several commercial wells are near the site, mainlyto the north and west. Groundwater from the site likely discharges east into the adjoiningwetlands. There is a shallow monitoring well on the southwest corner of the dump, related to thenearby Reilly Tar Superfund site.

Site Investigation

Six test trenches were dug at the site by STS in 1996 for geotechnical purposes identifiedfill and waste materials at the site. In 2002, eight soil borings were advanced by STS at the siteby use of a hollow-stem auger. The boring locations are shown in Figure 2. The boringsencountered a layer of sand to silty clay cover soils overlying up to 17.5 feet of fill and wastematerials. This layer in turn overlies native organic silts and outwash sands. Solid wastesencountered included wood, metal, concrete, coal cinders, plastic, and glass. Organic vapormeasurements 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 abackground level, in one boring. An organic vapor concentration of 8 PID units was found inboring B-3 at a depth of 2.5 to 7.5 feet below grade. Methane gas was also measured, but it wasnot 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 wereanalyzed for metals, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs),diesel range organics (DRO), pesticides, and herbicides. The last three samples, which werecollected in a community garden, were analyzed for metals, PCBs, and PAHs only. Severalmetals, 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 protectionof human health or groundwater quality in two samples (MPCA 2003). These criteria are knownas Soil Reference Values (SRVs) and Soil Leaching Values (SLVs). The SRV represents theconcentration of a contaminant in the soil below which normal dermal contact, inhalation, and/oringestion does not represent a human health risk. Because the site is located in a park, the mostrecent SRVs for recreational land use were used for comparison. The SLV represents theconcentration of a contaminant in soil above which the contaminant is able to leach into thegroundwater at levels in excess of drinking water standards. The surface soil analytical resultsare presented in Table 1. It should be noted that the chromium results in soil were for totalchromium, while the SRV and SLV are for hexavalent chromium. This form of chromium ismore toxic, but much less common in the environment. The screening criteria for hexavalentchromium are used, however, for the sake of conservatism.

Four samples of waste materials from individual borings (plus one duplicate), and one compositesample of the waste materials (plus one duplicate) were collected from depths of 8 to 10 feetbelow 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 werefound in the composite sample. Levels of some metals exceeded SRVs and/or SLVs in thecomposite sample, including chromium, copper, lead, and selenium. The results of the wastesamples are presented in Table 2.

Three samples of soil from beneath the waste materials (plus one duplicate) were collected todetermine if contaminants had leached from the waste materials down into the native soils. Eachsample was analyzed for VOCs, metals, DRO, PCBs, PAHs, pesticides, and herbicides. Thesample results are shown in Table 3. No VOCs, PCBs, PAHs, pesticides, or herbicides weredetected in these samples. Low levels of metals and DRO were detected, with levels of arsenicand 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 thedump. The sediment sample locations are shown in Figure 2. The samples were analyzed formetals, PCBs, PAHs, and pesticides. Elevated levels of metals (especially copper, cadmium, andlead) were detected in the sediment samples. Many of the metals were found to exceed MPCAsediment evaluation criteria, with concentrations of lead being especially high. PCBs were alsodetected and found to exceed the sediment evaluation criterion. The sediment sample analysisresults can be found in Table 4.

Surface Water

One sample (plus one duplicate) of surface water was collected from the pond located on theeastern 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 detectedin the sample, with the concentrations of copper and DRO exceeding their surface water qualitychronic standard for Class 2B waters, the applicable standards for this type of water body. Thesurface water sample results are presented in Table 5.

Groundwater

Groundwater samples were collected from six soil borings (with one duplicate) and wereanalyzed for VOCs, metals, PCBs, PAHs, DRO, pesticides, and herbicides. A groundwatersample was also collected from a permanent monitoring well located on the southwest corner ofthe site. The location of this well is visible in Figure 2; it was installed to monitor contaminationin the regional aquifer from the nearby Reilly Tar Superfund site. The results of the groundwatersamples are presented in Table 6.

VOCs were detected in two of the groundwater samples, from borings B-1 and B-2. The VOCsdetected include acetone, ethyl ether, methyl ethyl ketone, and naphthalene. None were detectedat concentrations approaching their respective MDH Health Risk Limits (HRLs) for privatedrinking water supplies. Two of the VOCs, acetone and methyl ethyl ketone, were also detectedat similar concentrations in the field blank, indicating that their presence in the samples may be aresult of laboratory contamination.

DRO was detected in four of the six samples. The concentrations of DRO ranged from 150micrograms per liter (g/L) in boring B-5 to 1,800 g/L in boring B-1. Three of the foursamples exceeded the MDH Health-Based Value (HBV) for DRO in drinking water of 200 g/L. DRO was also found in the field blank at a concentration of 130 g/L, so the results may not beentirely accurate. Two herbicides (acetochlor and prometon) and one pesticide (endosulfan)were found in the groundwater sample from boring B-1, with the concentration of acetochlorexceeding its HBV. The HRLs and HBVs represent levels of contamination in private drinkingwater supplies that MDH considers safe for daily human consumption over a lifetime. TheHRLs 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 werebelow detection limits or within background ranges with the exception of arsenic andmanganese. Arsenic was found in five of the six samples at concentrations as high as 71.7 g/L. There is no HRL for arsenic; the proposed federal Maximum Contaminant Limit (MCL) forpublic water supplies for arsenic is 10 g/L. Manganese exceeded the MDH HBV of 1,000 g/Lin the sample from boring B-3.

No contaminants were detected in the permanent monitoring well, and concentrations of metals were within background ranges.


II. DISCUSSION

Unpermitted or abandoned solid waste dump sites may pose a potential human health risk whenwaste 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 olddumps are often buried beneath a shallow layer of whatever type of soil is easily available at thetime. 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 sharpobjects, pits, or holes that result from uneven settling, or steep grades that may result fromimproper closure or maintenance of the site. For actual health risks or adverse health effects tooccur, both the chemicals (or hazards) must be present and people must comeinto contact with them.

Soil/Wastes

The majority of the Bass Lake Dump site is well covered and vegetated, with erosion exposingwastes only at the eastern edges of the dump. The results of laboratory analysis of surface soilsamples showed elevated levels of arsenic and pesticides in two samples, one of which (S-2) wascollected from the open playing field. The concentration of arsenic exceeded the MPCArecreational SRV of 12 milligrams per kilogram of soil (mg/kg). It is difficult todetermine, however, how often the fields are used by individual people or groups, so that theamount of potential human exposure is unknown. Since most of the site is covered andvegetated, frequent exposure is not expected. While concentrations of arsenic were belowlaboratory detection limits in the community garden area, only three samples were collected, andthe 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 thecommunity garden area. For this reason, MDH verbally recommended that the city of St. LouisPark not use the site for a community garden again this year, and the city has confirmed that itwill 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, thehuman health risk from contact with exposed contaminated soils or physical hazards is difficultto estimate.

Organic waste materials in a dump (if it was not burned regularly) often degrade and generatemethane and other gases. Low levels of chemical solvents may also be present in gas producedby old dumps. Together, these gases are referred to as "landfill gases." These frequently gases can migrate up to a few hundred feet from thedump site, depending on local conditions. This gas migration can result in explosive levels ofmethane 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 themajority 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 ofPCBs were also detected in the waste samples. People are unlikely to come into contact with theburied waste materials, however, unless the materials are excavated or disturbed. This type ofactivity should not be occurring on a regular basis, given the fact that the site is used as a publicpark. Workers who need to excavate at the site for utilities, landscaping, or otherpurposes should be notified of the presence of waste materials. A formal notice filedwith the property deed would also alert any future landowners to the presence of a dump. Thefrequency of exposure to site soil is expected to be low.

Elevated concentrations of arsenic, copper, lead, and manganese, and low levels of DRO werefound in soils samples collected beneath the waste deposit, indicating that the waste is capable ofleaching at least some contaminants. Some of these metals were also detected in samples ofgroundwater.

Groundwater

The degradation of solid waste produces leachate when infiltrating water contacts the waste anddissolves chemicals from it. The SLVs attempt to measure the ability of the waste materials orcontaminated soil to produce leachate. Leachate may discharge to surface water or infiltrate intogroundwater. Groundwater contaminated by leachate usually does not have any distinguishingappearance, 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 excessof 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 soilsbeneath the wastes showing similar contamination support this conclusion. Manganeseexceeded 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 frombeneath and around the Bass Lake Dump. This finding indicates that petroleum products werelikely disposed at the site and have leached from the waste materials and reached the uppermostgroundwater. Several pesticides and herbicides were also detected in groundwater, with levelsof one herbicide exceeding its HRL.

The data indicate that an area of groundwater contamination exists beneath and around thedump. The extent of the contamination in groundwater is not known, because the scope of theinvestigation was limited to the area immediately on and around the dump. The main types ofcontaminants detected at levels of concern (i.e. metals and DRO) typically do not migrate greatdistances in groundwater, however. Humans are unlikely to drink the contaminatedgroundwater, because the site is in a fully developed part of the Twin Cities area and nopotable water supply wells are located within approximately mile of the site in the suspecteddown-gradient direction. In addition, the shallow groundwater likely discharges into the nearbywetlands or lakes. A groundwater sample from the regional aquifer below the site did not showevidence of contamination from the dump. Therefore, no exposure via groundwater is expectedfrom this site.

Surface Water and Sediment

A surface water sample showed levels of copper and DRO in excess of chronic standards. Whilenot a human health concern, copper is very toxic to certain aquatic organisms. Other metalswere detected at lower concentrations.

Two sediment samples showed relatively high levels of metals in both samples and PCBs in onesample. These concentrations were well above their sediment screening criteria (which aredesigned to be protective of aquatic organisms), but they also approach the recreational SRVs forthe protection of human health, a fact that indicates that frequent human contact with thecontaminated sediments could pose an elevated health risk. Given the fact that the wetlands arerelatively isolated and not attractive for recreation, significant human contact is unlikely tooccur.

The contaminants may be entering the wetlands through the discharge of contaminatedgroundwater, through the runoff of rain and snow over exposed wastes or contaminated soilsnear the wetlands, or perhaps through the discharge of storm water from nearby roads. Thenature of the contaminants, especially DRO, suggestss that at least some of the contaminantsmay 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 concernto communities faced with contamination of their water, soil, air, or food. Children are at greaterrisk 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 intocontaminated 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 ofchemical exposure per body weight. In addition, the developing body systems of children cansustain permanent damage if toxic exposures occur during critical growth stages. Mostimportantly, children depend completely on adults for risk identification and managementdecisions, housing decisions, and access to medical care.

While the dump is located in a park used by children, significant contact with exposedcontaminated soils and waste materials does not appear to be frequent. Children are not exposedto the contaminated groundwater, and they are unlikely to use the wetlands for recreation.


III. CONCLUSIONS

The Bass Lake Dump is a somewhat unusual town dump in that it appears that incinerator ashwas 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 andgraded, and as a result physical hazards are minimal. In terms of contaminants, the ash/wastematerial appears to contain primarily heavy metals and petroleum products, which are leachinginto the groundwater. The extent of the groundwater contamination is not known, but it is notlikely 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.


IV. RECOMMENDATIONS

  1. In order to prevent exposure in the future, any exposed wastes at the site should becovered or removed and properly disposed.
  2. Any areas of bare soil on the playing fields should be covered with clean fill and seeded,especially in the area of surface sample S-2.
  3. Areas where erosion is occurring on the eastern edge of the dump should be covered andseeded to prevent further exposure of waste at the site and runoff into the wetlands.
  4. No wells should be installed on the site for potable water purposes.
  5. The site should not be used for community gardens.
  6. City or other workers who plan to excavate at the site for utilities, landscaping, or otherpurposes should be notified of the presence of waste materials and proper precautions should betaken.
  7. Institutional controls such as a notice filed with the property deed should be implemented to record the location of the dump for future reference.

V. PUBLIC HEALTH ACTION PLAN

MDH's Public Health Action Plan for the site will consist of:

  1. A letter to the MPCA and to city and county authorities advising them of MDH's recommendations; and

  2. A review of any additional available data and participation in any meetings or otherpublic outreach activities;

VI. REFERENCES

Agency for Toxic Substances and Disease Registry. Toxicological profile forarsenic. Atlanta: US Department ofHealth and Human Services;;2000 Sept.

Minnesota Pollution Control Agency. Risk-based site evaluation guidancedocuments. 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 LakeDump. 2002 Apr. 16.

STS Consultants LTD. Phase II environmental site assessment, Bass Lake Dump.2003 May 1.


PREPARERS OF REPORT

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


CERTIFICATION

This Bass Lake Dump Health Consultation was prepared by the Minnesota Department of Healthunder 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


FIGURES

Bass Lake Dump Site Location
Figure 1. Bass Lake Dump Site Location

Site Map
Figure 2. Site Map

Cross-Section Location
Figure 3. Cross-Section Location

Cross-Section A-A'
Figure 4. Cross-Section A-A'

TABLES

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:/em>
- - = 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


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