PETITIONED PUBLIC HEALTH ASSESSMENT
KINGS CREEK
(a/k/a FORT BELKNAP INDIAN RESERVATION/ZORTMAN MINING INCORPORATED)
LODGEPOLE, BALINE COUNTY, MONTANA
In September 1995, the Fort Belknap Community Council petitioned the Agency for Toxic Substances and Disease Registry (ATSDR) to evaluate two large, open-pit, cyanide heap leaching, gold mines located adjacent to the south end of the Fort Belknap Reservation. The council believed the mines posed a health hazard to the people of the reservation by releasing toxic substances into the environment, especially into drinking water supplies. Concerns were raised by community residents in the petition letter and subsequent meetings with ATSDR representatives about the quality of the drinking water and pollution of surface water, sediments, and air on the reservation. During November 1995, ATSDR conducted a site visit to Fort Belknap Reservation to meet with the Fort Belknap Community Council about its concerns and then again in 1996 to conduct public availability sessions in Hayes, Lodge Pole, Landusky, Agency, and Malta. The results of the agency's evaluation of the concerns expressed by the petition were presented to the Fort Belknap Community Council in May 1996.
Data from the drainages flowing in the direction of Fort Belknap and groundwater were reviewed to determine what contaminants were present at concentrations above the ATSDR comparison values. ATSDR identified a past completed pathway of exposure to lead in drinking water from some private wells. The levels detected do not pose a health threat, and subsequent sampling failed to show any lead contamination. Private well water has elevated levels of naturally occurring salts and minerals, however the levels are not expected to cause adverse health effects.
Based on the data reviewed, ATSDR concludes that the gold mining operations are no apparent public health hazard to the residents of Fort Belknap. Additional studies of the groundwater and surface water are planned. These data will be useful in evaluating potential future exposure pathways.
ATSDR supports the planned community health evaluation and recommends that any additional environmental data collected utilize analytical methods that would permit detection of substances at or below known health-based comparison values. If requested, ATSDR will review any additional environmental or health outcome data provided.
This public health assessment (PHA) summarizes the environmental and health outcome data provided to ATSDR, and responds to community concerns expressed to ATSDR staff, since the petition was received. This public health assessment is not a medical examination nor a community health study. It is a review of information about hazardous substances at the site and it evaluates whether exposure to those substances might cause any harm to people.
Fort Belknap was established in 1869 near the present town of Chinook, Montana. The new fort served as a trading post and became the government agency for the Gros Ventre and Assiniboine Indians living in the area. On May 1, 1888, a congressional act set aside the land for the Fort Belknap Reservation. Later that year, the agency moved from Chinook to its present location 5 miles east of Harlem, on the northwest corner of the reservation.(Indian Claims Commission, Undated). Also, during 1888, lode gold was found in the Little Rockies shortly after the Fort Belknap Reservation was founded.
In 1895, a congressional commission was sent to Fort Belknap to negotiate the purchase of the Little Rockies from the tribes. The Gros Ventre and the Assiniboine vehemently opposed the "sale of the mountains," which was advocated by federal commissioners who were assigned to negotiate the sale of the gold mining country in 1896 (Indian Claims Commission, Undated). The Assiniboine and Gros Ventre representatives were told by the commissioners that they would no longer be provided "beef, cattle, flour, wagons, or anything else" if they did not sell a strip of land, 7 miles long and 4 miles wide for $360,000. Eventually an agreement was reached on October 9, 1895, which sold the southern portion of the Little Rockies to the United States (Grinnell Agreement, 1896).
B. Creation of King Creek tailings
The mining for gold and silver in the Little Rocky Mountains (Little Rockies) of Montana began in 1884 (Morrison Knudsen, 1993a) as placer operations (Indian Claims Commission, Undated). Between 1884 and the 1930s, mining in the Little Rockies involved removal of the ore-bearing rock and transportation to area mills (Morrison-Maierie Inc., 1979) resulting in the production of mine tailings. The mining in the King Creek drainage took place at the August and Little Ben mines. Initially, gold mining involved crushing the ore-bearing rock and transporting it to a mill for leaching of the precious metals with a weak cyanide solution. However, in the 1930s, a 150-ton mill and cyanide leaching plant were built and began operating at the Little Ben Mine. The mill produced 150 tons of ore crushed to 10 mesh daily (Morrison Knudsen, 1993a). Tailings from this mill were deposited in the headwaters of King Creek.
C. Migration of tailings in King Creek drainage
The mill tailings located in King Creek (see map of surface water drainages, Appendix A) did not pose a problem until sometime in the 1960s, when sedimentation from the tailings increased noticeably. The deposition of large amounts of tailings within the stream adversely affected fish and wildlife habitats in the Little Peoples Creek drainage. It also resulted in siltation of irrigation equipment located at the mouth of Mission Canyon (Morrison-Maierie Inc., 1979). In 1979 the tailings extended from the headwaters where they had been initially deposited (approximately 1.5 miles north of the town of Landusky, Montana) to a location in the Little Peoples Creek drainage near Hays (Morrison-Maierie Inc., 1979). Included in this stretch of the creek are cultural and recreational areas used by the Assiniboine and Gros Ventre Indian tribes of the Fort Belknap Reservation.
Since 1979, a number of activities have changed the quantity and location of the tailings in the Little Peoples Creek drainage. During the 1980s, Zortman Mining Inc. (ZMI) removed about 75% of the old mill tailings from the King Creek drainage for use at its current operation (DOI, 1996). In July 1993, a flood resulting from unusually heavy rainfall, sent King Creek waters flowing over the Cumberland Dam spillways. The beaver dams located further down the King Creek drainage were washed out releasing tailings that were previously contained by the beaver dams (Morrison Knudsen, 1993b). The amount of tailings that moved and the ultimate resting place is not known.
Later in 1993, ZMI removed the remaining tailings from above the Cumberland Dam (DOI, 1996). Thus, the only tailings remaining in the Little Peoples Creek drainage are the unknown quantity that washed downstream of the Cumberland Dam into Fort Belknap.
The U.S. Environmental Protection Agency (EPA) 
, Region VIII, conducted a Preliminary
Assessment and Site Investigation for the King Creek Mine Tailings Site (Morrison Knudsen, 1993a
& 1993b); these activities are used to rank sites for inclusion on the National Priorities List (NPL). To date, EPA has not proposed the Fort Belknap site for inclusion on the NPL.
D. Modern cyanide heap leach gold mining
Modern, large-scale, heap leach gold mining has taken place since 1979 at the Landusky and Zortman mines operated by ZMI, a subsidiary of Pegasus Gold Corporation. Both the Zortman and Landusky operations are open-pit gold mines that utilize heap leaching of gold ore with a cyanide solution. Gold is recovered from the cyanide solution using either zinc precipitation or carbon adsorption methods (DOI, 1996).
E. Releases from the Zortman and Landusky mines
There have been several releases from the Zortman and Landusky mines.
A lawsuit was filed August 30, 1993, by the Montana Department of Health and Environmental
Science (MDHES), which is now the Montana Department of Environmental Quality (MDEQ),
Division of Water Quality, against Pegasus Gold and ZMI for violations of the Montana Clean
Water Act (EPA, 1996). Eventually EPA and several groups from the reservation (the Gros Ventre
Tribe, the Assiniboine Tribe, the Fort Belknap Community Council, and a citizens group known as
the Island Mountain Protectors [IMP]) joined this lawsuit. On July 22, 1996, a settlement was
signed by all the parties. The settlement provided for $4.5 million in penalties to be paid to EPA and
the state of Montana, as well as a partial cash settlement with the tribes and several supplemental
environmental projects (SEPs), including a community health evaluation, an aquatic study, and
improvements to the drinking water systems at Hays and Lodgepole on the Fort Belknap
Reservation. The settlement also included requirements for a Ground Water Study Plan, which will
provide the information needed to determine whether there are impacts from mine wastewater on the
area groundwater. The defendants (ZMI, etc.) also agreed to provide a bond or surety totaling $32.3 million to the state of Montana to cover the costs of long-term water treatment (EPA, 1996).
On May 11, 1992, ZMI proposed an expansion of mining operations at the Zortman Mine in the Little Rockies. The proposal included expanding the existing mine pits to include the development of sulfide ore deposits. This will require construction of new facilities including a waste rock disposal area, crushing facilities, a leach pad, a new processing plant and ponds, and a limestone quarry (DOI, 1996). A draft environmental impact statement (EIS) was released in August 1995 and the final EIS was released by the MDEQ and the U.S. Department of Interior, Bureau of Land Management (BLM), in March 1996. The EIS addresses major environmental impacts and issues associated with the proposed expansion of both the Zortman and Landusky mines (DOI, 1996). The record of decision was released October 1996 approving the expansion of the mines as described in the preferred alternative (Alternative 7) of the final EIS.
In October 1992, ATSDR was requested to conduct a health consultation to address health concerns among the population at the reservation related to the mine tailing contamination in King Creek. Three consultations were completed; they are summarized below (see Appendix B for the complete documents).
NOTE: The settlement of the water quality litigation described previously requires the implementation of a comprehensive groundwater study, which should help address hydrology concerns. The data provided to ATSDR for review did not reveal mine or mill tailings or sediments with elevated levels of metals in areas where human contact was likely.
In September 1995, the Fort Belknap Community Council petitioned ATSDR to evaluate two large, open-pit, cyanide heap leaching, gold mines located adjacent to the south end of the reservation. The council believed that the mines pose a health hazard to the people of the reservation by releasing toxic substances into the environment, especially into drinking water supplies.
ATSDR personnel conducted a visit to Fort Belknap and the surrounding area November 5-8, 1995, as part of the response to the September 1995 petition. Several groups from the community met with ATSDR personnel during the visit, including:
ATSDR met with representatives of the groups listed above to gather all available environmental data pertaining to the issues under investigation, as well as to initiate contact with the various parts of the site community. In addition to information gathering, the ATSDR site team visited several of the areas about which concerns had been expressed.
K. Public Availability Sessions
Concerns were raised by community residents during public availability sessions with ATSDR representatives held in March 1996. Concerns about the quality of the drinking water and pollution of surface water, sediments, and air, as well as numerous concerns about health, were expressed.
According to the 1990 Census of Population and Housing (U.S. Bureau of Census, 1992), the demographic statistics for within 1 mile of the site indicate that 55 persons reside in 48 households. Of the 55 persons, 42 are white; none are black; 7 are American Indian, Eskimo, Aleut; none are Asian or Pacific Islander; 1 is of Hispanic origin and none are members of other ethnic groups. There are 7 children aged six or younger, 12 females aged 15-44 and two adults aged 65 and older. Please refer to the demographics maps located in Appendix A.
A number of environmental and health concerns related to perceived contamination from the mine and other issues have existed in and around the Fort Belknap community for several years. Many of these concerns have revolved around differences in data collected by various interested groups. Many other concerns have revolved around the aesthetic qualities of drinking water on the reservation. This document was prepared using all the environmental data that ATSDR was provided by the many different agencies, organizations, and individuals (see previous section, Site Visit) the agency met with.
Because these data were collected for wide variety of uses, the sampling points, detection levels, analysis methods, and quality assurance and quality control procedures all varied considerably. This variability resulted in numerous uncertainties about the accuracy and precision of the data for numerical and statistical analysis, as well as uncertainties related to detailed comparison between data sets. Therefore, this discussion makes only qualitative comparisons. (See Appendices C and D for more information about the data used in this report.) If detailed quantitative data comparisons are desired, new data using standardized collection and analytical methods, health based detection levels, etc. will have to be collected.
III. ENVIRONMENTAL CONTAMINATION AND PATHWAY ANALYSIS
A. Environmental Data and Exposure Pathways
Data from each of the drainages flowing in the direction of Fort Belknap (King Creek/Little Peoples Creek from the Landusky Mine and Glory Hole/Lodge Pole, Beaver, and Big and Little Warm Creeks from the Zortman Mine) were reviewed to determine what contaminants were present at concentrations above the ATSDR comparison values (i.e., which specific contaminants or groups of contaminants were found at elevated levels). See Appendix A for a map of surface water drainages.
For a definition of comparison values and how ATSDR uses them, see Appendix E; a brief definition and explanation is also provided in the Toxicological Evaluation section. Briefly, two types of comparison values are used in this document: (1) risk-based or human health-based values, concentrations of environmental contamination known to be safe (that is, items in the tables listed as AL, EPA SLG, MCL, pMCL, RBC, child RMEG, WHO), and (2) secondary standards, concentrations of environmental contamination known to cause unpleasant, but not dangerous, characteristics in water (that is, those listed in the tables as USGS, sMCL). Each of these acronyms is explained in the tables and further described in Appendix E.
Once a determination has been made about which contaminants are present at concentrations greater than the comparison values, the data are evaluated to determine whether the contamination is likely to move in the environment (e.g., from stream sediment to stream water, or from soil to air) and if people are likely to be exposed to the contamination.
Exposure pathways can be completed or potential. A completed pathway indicates that human exposure to contaminants has occurred in the past, is occurring, or will occur in the future. A potential pathway indicates that exposure could have occurred in the past, is occurring, or will occur in the future. An exposure pathway can be eliminated from consideration if exposure has never occurred and never will occur. If there is uncertainty about whether the contaminants of concern in an exposure pathway are site related, the pathway will be evaluated as if they were.
The data provided to ATSDR for this document indicate that the only completed pathway is drinking some of the water used for residential purposes at Fort Belknap (see the Toxicological Evaluation in the Health Concerns section for more information). Several other pathways are potentially completed, including accidentally drinking contaminated surface water present in the Little Peoples Creek drainage, Lodge Pole drainage, and other streams that may receive runoff from either of the mines; swimming or wading in the same contaminated surface waters; accidentally eating tailings materials located in Mission Canyon because hands were not washed before putting them in a mouth or as a result of pica behavior; and breathing air contaminated with cyanide and other contaminants blown from the mining operations (see the Air Quality discussion included in the Environmental Concerns section for more information).
TABLE 1. Table 1 presents a summary of surface water data from selected sampling locations in the Little Peoples Creek Drainage (King Creek, Swift Gulch, South Big Horn Creek, and Little Peoples Creek), which receives surface water flow from the Landusky mine. The levels of sulfate, nitrate, and manganese in those surface waters exceeded human health-based comparison values. Lead analyses were conducted using a detection level that was higher than the ATSDR comparison level. Consequently, ATSDR assumed the concentration exceeded the comparison value for purposes of this evaluation as a true concentration for lead could not be determined.
TABLE 2. Table 2 presents a summary of the data from selected sampling locations in the drainages receiving surface water runoff from the Zortman mine: Lodge Pole Creek drainage (Glory Hole Creek, Lodge Pole Creek), Beaver Creek, Little Warm Creek and Big Warm Creek. The levels of sulfate, antimony(1), beryllium(2), manganese, and sodium in those sampling locations exceeded human health-based comparison values.
TABLE 3. Table 3 compares domestic well data collected at the Fort Belknap Reservation with data collected from wells in areas with known acid rock drainage problems. The levels of sulfate, iron, lead(3), nitrate, and sodium in the well water exceeded human health-based comparison values.
TABLE 4. Table 4 presents analytical data from three environmental media: groundwater collected from domestic or public supply wells, groundwater collected from springs or monitoring wells, and surface water collected from various surface water stations. Each of these media are subdivided into drainages: Fort Belknap (which includes all groundwater or surface water collected within the reservation boundary); Landusky (which includes all groundwater or surface water collected from any drainage of the Landusky Mine that is not within the reservation boundary); and Zortman (which includes all groundwater or surface water collected from any drainage of the Zortman Mine that is not within the reservation boundary).
The data in Table 4 are presented as ranges for each medium and drainage. Any maximum value that was detected from a Landusky or Zortman drainage that was flowing in the direction of Fort Belknap, but was not within the reservation boundary, has been indicated with an asterisk (*). All other maximum values expressed in Table 4 are from drainages flowing away from the reservation.
TABLE 5. Table 5 presents analytical data from rock, tailings, and sediment samples. Rock samples were collected from various locations at both the Zortman and Landusky mines. Tailings samples included in the '78-'79 and '93 data sets were collected from the King Creek/Little Peoples Creek drainage. Tailings/sediments were collected from the King Creek/Little Peoples Creek, Big Warm Creek, and Beaver Creek drainages.
The data presented in these tables are the basis for the discussion presented in the next section.
TABLE 1. Surface Water Results from Selected Locations in the King Creek/little
Peoples Creek Drainage, North of the Landusky Mine
(Based on surface water data from ZMI and the Fort Belknap Reservation)
| Contaminants (ppm) | Comparison Values (ppm) | L5 (King Creek headwaters) | L6 (King Creek just inside res boundary) | L19 (Swift Gulch) | FB15 (Near KC headwaters at old beaver ponds) | FB15b (250 ft. below old beaver ponds) | FB12 (South Big Horn Creek) | FB10 (North Fork LPC) |
| Sampling Dates | 1979 - 1994 | 1979 - 1994 | 1985 - 1995 | 8/94 - 7/95 | 8/95 - 11/95 | 7/95 - 3/96 | 8/94 - 3/96 | |
| Specific Conductivity (µmhos/cm) | 500µmhos/cm (USGS) | 340 - 2010 | 293 - 838 | 48 - 593 | 535 - 762 | 707 | 313 | 358 - 427 |
| Total Dissolved Solids (TDS) | 500 (sMCL) | 351 - 1930 | 293 - 838 | 53 - 419 | 394 - 450 | 447 - 483 | 216 - 335 | 252 - 300 |
| Sulfate (SO4) (mg/L) |
250 (sMCL) 500 (pMCL) |
98 - 1070 | 69 - 260 | 12 - 210 | 17 - 123 | 116 - 123 | 72 - 124 | 12 - 24 |
| Nitrate + Nitrite as N | 10 (MCL) | 7.3 - 36.9 | ND - 1.29 | ND - 1.49 | <0.05 | <0.05 | <0.05 | <0.05 - 0.08 |
| Iron | 0.3 (sMCL) 11 (RBC) |
(trc)ND - 1.47 | (trc)0.01 - 1.47 | (trc)ND - 2.11 | 0.16 - 2.07 | 0.94 | <0.05 | <0.05 - 0.14 |
| Lead | 0.015 (AL) | (trc)ND - 0.05 | (trc)ND - 0.02 | (trc)ND -0.02 | <0.05 | <0.05 | <0.05 | <0.05 |
| Manganese | 0.05 (sMCL, child RMEG) 0.84 (RBC) |
(trc)ND - 0.15 | (trc)ND - 1.19 | (trc)ND - 0.08 | 0.11 - 0.4 | 0.29 | <0.02 | <0.02 |
NA Not Analyzed
ND Not Detected
(trc) Total Recoverable
See Appendix E for definitions and sources of
the comparison values used in this table.
TABLE 2. Surface Water Results in The Gloryhole, Lodgepole,
Beaver, Little Warm, And Big Warm Creek Drainages, North of The Zortman Mine
(Based on surface water data from ZMI and Fort Belknap)
| Contaminants (ppm) | Comparison Values (ppm) |
Z-5 (Gloryhole Ck near mine boundary) | Z-7 (Lodgepole Ck near reservation boundary) | Z-31 (Beaver Creek @ 1st tributary confluence from headwaters) | Z-39 (Beaver Creek @ 2nd confluence from headwaters) | Lodgepole Creek (S. side of Rt 11) | Big Warm (above pond) | Beaver Creek (W. of Rt 15) | Little Warm (1 mi. E. of Rt. 15) |
| Sampling dates | 5/81 - 10/93 | 1990 - 1995 | 1990 - 1995 | 1994 - 1995 | 8/94 - 4/96 | 8/94- 12/95 | 4/95 - 4/96 | 8/94 - 10/95 | |
| pH (S.U.) | 6.5 - 8.5 (S.U.) | 7.1 - 8.2 | 7.4 - 8.5 | 7.1 - 8.0 | 7.9 | 7.9 - 8.5 | 7.5 - 7.8 | 7.9 - 8.3 | 7.5 - 8.0 |
| Specific Conductivity (µmhos/cm) |
500 µmhos/cm (USGS) | 165 - 486 | 201 - 433 | 135 - 252 | 168 - 310 | 482 - 611 | 1880 - 2170 | 497 - 532 | <7 - 2220 |
| Total Dissolved Solids (TDS) | 500 (sMCL) | 105 - 292 | 83 - 267 | 65 - 158 | 127 - 243 | 287 - 364 | 1450 - 1870 | 288 - 326 | 1430 - 2000 |
| Sulfate (SO4) | 250 (sMCL) 500 (pMCL) |
0.15 - 65 | 12 - 36 | 5.0 - 16 | 6 - 20 | 25 - 34 | 169 - 1120 | 13 - 38 | 778 - 1160 |
| Antimony | 0.006 (MCL) | NA | NA | NA | NA | <0.05 | <0.05 | <0.05 - 0.06 | <0.05 |
| Beryllium | 0.004 (MCL) | NA | NA | NA | NA | <0.005 - 0.006 | <0.005 - 0.007 | <0.005 | <0.005 |
| Chromium | 0.05 (MCL) | <0.010 - <0.020 | NA | NA | NA | <0.02 | <0.02 | <0.02 | <0.02 - 0.02 |
| Iron | 0.3 (sMCL) 11 (RBC) |
0.06 - 2.84 | (trc)ND - 0.68 | (trc)ND - 0.32 | (trc)ND - 0.5 | 0.24 - 0.48 | <0.05 - 0.15 | .36 - .54 | <0.05 - 0.12 |
| Manganese | 0.05 (sMCL,
child RMEG) 0.84 (RBC) |
<0.10 - 21 | (trc)ND | (trc)ND | (trc)ND | 0.06 - 0.13 | <0.02 | 0.4 - 0.6 | <0.02 |
| Sodium | 20 (USGSb) - 200 (WHO) | 1.0 - 7.0 | 3 - 7 | 2 - 4 | 3 - 4 | <1 - 6 | 64 - 79 | <1 - 19 | 55 - 70 |
NA Not Analyzed
ND Not Detected
(trc) Total Recoverable
See Appendix E for definitions and sources of
the comparison values used in this table.
TABLE 3. Fort Belknap Domestic Well Data And Groundwater
Data From Known Areas With Acid Rock Drainage (ARD)
(Based on data from the EIS and Fort Belknap)
| Contaminants (ppm) | Comparison Values | '78 Domestic Well Data | '90 - 95 Domestic Well Data | ZL-142 (Ruby Gulch-bedrock) | ZL-143 (Ruby Gulch-alluvium) | ZL-119 (Montana Gulch-bedrock) | ZL-113 (Montana Gulch-alluvium) | ZL-125 (Montana Gulch-alluvium) |
| pH (S.U.) | 6.5 - 8.5 S.U. | 7.0 - 8.8 | 6.9 - 8.9 | 6.5 - 7.6 | 7.5 - 7.9 | 7 - 8 | 6.5 - 7.9 | 7.0 - 9.5 |
| Specific Conductivity (µmhos/cm) | 500 µmhos/cm (USGS) |
310 - 6100 | 379 - 6770 | 982 - 1990 | 1120 - 1300 | 488 - 940 | 541 - 2450 | 602 - 1250 |
| Total Dissolved Solids (TDS) | 500 (sMCL) | 160 - 4100 | 325 - 5540 | 829 - 1800 | 954 - 1150 | 293 - 577 | 497 - 2250 | 390 - 986 |
| Sulfate (SO4) | 250 (sMCL) 500 (pMCL) |
3 - 2550 | 10 - 3110 | 377 - 1070 | 569 - 658 | 91 - 190 | 27 - 1180 | 131 - 562 |
| Arsenic | 0.05 (MCL) | <0.002 - 0.006 | <0.001 - 0.0314 | ND | ND | ND | ND | ND |
| Iron | 0.3 (sMCL) 11 (RBC) |
<0.01 - 11.5 | <0.01 - 7.07 | ND | 0.07 - 0.07 | ND | ND - 0.11 | 0.14 |
| Lead | 0.015 (AL) | <0.01 - <0.13 | <0.001 - 0.0179 | ND | ND | ND | ND - 0.03 | ND -0.01 |
| Nitrate | 10 (MCL) | <0.1 - 31 | <0.05 - 0.72 | 0.81 - 3.77 | 0.92 - 0.92 | 3.35 - 5.67 | 0.27 - 6.23 | 0.87 - 2.90 |
| Sodium | 20 (USGSb) - 200 (WHO) | 1 - 1250 | 1.3 - 1480 | 6 - 12 | 7 - 9 | 2 - 178 | 2 - 8 | 15 - 27 |
ND Not Detected
See Appendix E for definitions and sources of
the comparison values used in this table.
TABLE 4. Summary of Surface Water And Groundwater Data in
the Fort Belknap/Zortman Mining Inc. Area From a Variety of Sources1-9
( on next page)
|
GROUNDWATER
|
SURFACE WATER
|
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|
Domestic Wells
|
Springs and Monitoring Wells
|
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| Contaminants (mg/L) |
Comparison Values (ppm)
|
Ft. Belknap1
|
Landusky2
|
Zortman3
|
Ft. Belknap4
|
Landusky5
|
Zortman6
|
Ft. Belknap7
|
Landusky8
|
Zortman9
|
| pH (S.U.) | 6.5 - 8.5 S.U. | 6.9 - 8.9 | 5.92 - 8.24 | 6.26 - 7.89 | 7.1 - 8.1 | 3.3 - 11.8 | 2.60 - 8.7 | 6.9 - 8.6 | 2.7 - 8.6 | 2.5 - 8.5* |
| Specific Conductivity (µmhos/cm) | 500 µmhos/cm (USGS) | 379 - 6770 | 382 - 3390 | 373 - 438 | 167 - 1760 | 190 - 3390 | 141 - 9990 | <7 - 2220** | 48 - 10,700 | 53 - 4990 |
| Total Dissolved Solids | 500 (sMCL) | 325 - 5540 | 193 - 1100 | 163 - 272 | 133 - 1480 | 140 - 3350 | 106 - 20200 | 225 - 2000** | 48 - 14,700 | 15 - 6940 |
| Sulfate | 250 (sMCL) 500 (pMCL) |
10 - 3110 | 37 - 608* | 31 - 46 | 32 - 843 | 27 - 2360 | 11 - 6290 | <5 - 1160 | 14 - 9960 | 3* - 3330 |
| Antimony | 0.006 (MCL) | <0.05 | — | — | <0.05 | — | — | <0.05 - 0.06 | — | — |
| Arsenic | 0.05 (MCL) | <0.005 - 0.0314 | <0.005 - 0.158 | <0.005 | <0.001- 0.001 | ND - 0.50 | ND - 1.2 | <0.001 - 0.04 | ND - 5.51 | ND - 0.24 |
| Beryllium | 0.004 (MCL) | <0.001 | — | — | <0.001 | — | — | <0.001 - 0.007 | — | — |
| Cadmium | 0.005 (MCL) | <0.001 - 0.002 | <0.001 | <0.001- 0.002 | <0.001 | ND - 0.08 | ND - 0.56 | <0.001 - 0.005 | ND - 0.6 | ND - 0.35 |
| Chromium | 0.05 (MCL) | <0.001 - 0.003 | <0.001 | <0.001 | <0.001 | — | — | <0.001 - 0.24 | BQL - 0.03* | — |
| Copper | 1 (MCL) | <0.001 - 0.93 | BDL - 0.002 | BDL - 0.01 | <0.001 | ND - 0.30 | ND - 43.5 | <0.001 - 0.039 | ND - 2.34 | ND - 14.8 |
| Cyanide | 0.20 (MCL) | <0.005 | <0.005 | <0.005 | <0.005 | ND - 125 | ND - 0.24 | <0.005 | ND - 0.14 | ND - 1.38 |
| Iron | 0.3 (sMCL) 11 (RBC) |
<0.01 - 7.70 | <0.03 - 5.99 | <0.03 | <0.003 - 0.06 | ND - 13.3 | ND - 346 | <0.03 - 2.07 | ND - 536 | ND - 247 |
| Lead | 0.015 (AL) | <0.001 - 0.0179 | <0.01 - 0.03 | <0.01 | <0.001 - 0.01 | ND - 0.06 | ND - 0.10** | <0.001 - 0.20 | ND - 0.34* | ND - 0.19 |
| Manganese | 0.05 (sMCL, child RMEG) 0.84 (RBC) |
<0.005 - 1.36 | <0.02 - 0.16 | <0.02 | <0.01 | ND - 46.7 | ND - 72.2 | <0.01 - 0.4 | ND - 110 | ND - 27.6 |
| Nitrate/Nitrite | 10 (MCL) | <0.05 - 0.72 | <0.05 - 6.38 | 0.22 - 0.29 | <0.05 - 0.069 | ND - 19.3* | ND - 4.4 | <0.05 - 0.21 | BQL - 36.9* | ND - 23.4 |
| Sodium | 20 (USGSb) - 200 (WHO) |
1.3 - 1480 | 5 - 84 | 4 - 5 | 1.1 - 7.6 | 2 - 178 | 3 - 764 | <1 - 78 | 1 - 1650 | 1 - 286 |
| Zinc | 5 (sMCL) 3 (child RMEG) |
<0.01 - 0.9 | <0.01 - 0.05 | <0.01 - 0.03 | <0.003 - 0.007 | ND - 9.21 | ND - 18 | <0.003 - 0.1 | ND - 25.4 | ND - 13.5 |
ND Not Detected
BDL Below the detection level.
* Sample was collected in a drainage flowing in the direction of the Fort Belknap
Indian Reservation.
** Value reported in table is the maximum value reported excluding data collected
before 1990 or from sampling points not expected to be affected by ZMI.
See Appendix E for definitions and sources of the comparison values used in this
table.
TABLE 5. Summary of Hard Rock, Tailings, and Sediment Data
in the Fort Belknap/ZMI Area From a Variety of Sources 1-4
|
'78 - '79 Tailings Data2
|
'93 Tailings Data3
|
'87 - '93
Sediment/Tailings Data4 |
||||||
| Contaminant (ppm) | Comparison Values (ppm) | Hard Rock1 | Water-Soluble Metals | Liquid | Solid | Above Cumberland Dam | Below Cumberland Dam | |
| Antimony | 20 (child RMEG) | 8 - 53 | 5.5 UJ - 9.0 UJ | 6.3 UJ - 8.8 UJ | ||||
| Arsenic | 20 (child RMEG) | 10 - 443 | 0.01 - 0.18 | <0.002 - 29 | <0.01 - 40 | 74.4 - 112 | 71.7 - 80.2 | 7.5 - 1,1610.0 (sic) |
| Beryllium | 300 (child RMEG) | 2.9 - 18.7 | 0.58 - 1.1 | 0.51 - 0.67 | <0.28 - 0.48 | |||
| Cadmium | 50 (child EMEG) | <1 - 5 | 0.1 - 6.52 | |||||
| Chromium | 300-50,000 (child RMEG) | 60 - 1503 | 7.5 J - 18.6 J | 8.8 J - 13.5 J | <0.5 - 33 | |||
| Copper | 3100 (RBC) | 5 - 505 | 24.3 - 49 | 20.6 - 29.8 | 0.99 - 13.8 | |||
| Cyanide | 1000 (child RMEG) | < 0.01 (BDL) | <0.002 - 0.16 | 0.01 - 0.16 | ||||
| Iron | 23,000 (RBC) | 4,100 - 63,340 | 7650 - 12800 | 7720 - 11200 | 5990 - 14800 | |||
| Lead | 400 ( EPA SLG) | < 2 - 182 | < 0.02 - 0.15 | <0.01 - 60.1 | 1.2 - 94 | 175 J - 400 J | 213 J - 236 J | 3.5 - 2300 |
| Manganese | 7000 (Child RMEG) | 10 - 824 | 305 J - 778 J | 353 J - 390 J | ||||
| Selenium | 50 (Child RMEG) | ND - 8 | ||||||
| Sodium | 20 - 200 (WHO) | 0.15 - 3.32 | 44.5 - 72.4 | 65.6 - 70.6 | 59.7 - 104 | |||
| Zinc | 20,000 (Child RMEG) | 11 - 185 | 0.23 - 71.9 | 123 J - 227 J | 117 J - 156 J | 12.3 - 194 | ||
U The element was not detected at or above the reported detection
limit.
J The associated numerical value is an estimated quantity because the quality control criteria were not met.
BDL Below the detection level.
ND Not detected.
See Appendix E for definitions and sources of the comparison values used in this table.
The summary below addresses environmental concerns expressed to ATSDR staff. When appropriate, the chemicals discovered to be elevated above either type of comparison value are discussed. See the Toxicological Evaluation section for more information about health effects associated with exposure to the chemicals.
The primary concern expressed by many community members pertained to the pollution of surface water and groundwater on the reservation.
Data collected by the United States Geological Survey, the United States Bureau of Indian Affairs, and the Montana College of Mineral Science and Technology revealed the sedimentary aquifers in and around the Fort Belknap Indian Reservation to have always had variable water quality. The Groundwater Information Center (GIC) of the Montana Bureau of Mines and Geology has indicated that water supply wells throughout Blaine, Phillips, and Valley counties completed in the Judith River and Eagle Formations have iron, manganese, TDS, and sulfate concentrations exceeding federal secondary drinking water standards (ZMI, 1997). Data collected in the southwest portion of the Fort Belknap Indian Reservation going back to 1936 indicate the same elevations of these parameters (Feltis 1983).
Surface water flowing north from the Landusky mine through King Creek contained elevated levels of specific conductivity, total dissolved solids (TDS), sulfate, nitrate, iron, lead (lead was assumed to be above the comparison value because the analyses were conducted with a detection level greater than the comparison value and, therefore, a true concentration could not be determined) and manganese (Table 1). Concentrations decreased as the water flowed down the drainage toward the reservation. By the time the water reached the confluence with South Big Horn Creek, there were no metals or other water quality indicators present at levels that could pose problems either aesthetically or from a human health perspective. ATSDR is unable to say whether lead was elevated in the monitored drainages because the apparent detection limit of 0.05 parts per million (ppm) was well above the comparison value of 0.015 ppm.
Surface water originating near the Zortman Mine in Glory Hole and Lodgepole Creeks contained iron and manganese at levels exceeding the comparison values (Table 2). Samples taken from Lodgepole Creek on the reservation indicated levels of specific conductivity, iron, and manganese that exceeded the comparison values. Big and Little Warm Creeks, which also flow north from the Zortman mine, contained sulfates, specific conductivity, and TDS (Table 2) at concentrations above ATSDR comparison values. Results from samples taken along Beaver Creek indicated the presence of specific conductivity, iron, and manganese above comparison values. ATSDR is unable to say whether antimony was elevated in the monitored drainages because sites were either not analyzed or the apparent detection limit of 0.05 ppm was well above ATSDR's comparison values for this metal, which is 0.006 ppm.
All other values for surface water (Tables 1 and 2) showed wide variation, but were generally within health-based comparison values. There does not appear to be any pattern or trend to this data. However, sampling additional points between the mines and the reservation sampling points might provide data that would clarify these results.
Table 3 presents domestic well data collected at the Fort Belknap Reservation in 1978 (pre-ZMI) and in the current time period (1990 - 1995). It also shows groundwater results from monitoring wells screened in bedrock and alluvial aquifers in the Ruby and Montana gulches. The maximum levels of specific conductivity, TDS, sulfate, lead, nitrate, and sodium measured in domestic wells exceeded comparison values and, with the exception of nitrate, were 5-8 times higher than the corresponding values in groundwater at the Montana and Ruby gulches, which are the drainages most affected by the mines.
Maximum concentrations from the 1990 - 1995 domestic well data for specific conductivity, TDS, and sulfate were 10-35% higher than the values from 1978; however all minimum concentrations were below comparison values. None of the increases appear to be out of the ordinary, especially in view of the fact that, historically, the concentrations have always been high. The maximum levels of lead and nitrate in domestic wells significantly exceeded health-based comparison values in 1978, but were near or within comparison values in 1990-1995. The other substances in the domestic well samples appear to be isolated detections and represent no apparent trend or pattern of groundwater contamination (Tables 3 and 4).
Several people were concerned about lead contamination of their wells.
The maximum level of lead found in the data review by ATSDR was 0.308 milligrams per liter (mg/L), which is about 20 times the comparison value of 0.015 mg/L. It is from a home in Fort Belknap Agency, which is located some miles from the mining. This concentration was only detected in one well and was not duplicated in that well during a later sampling (Fort Belknap Utilities, 1994 - 1995). Only one other well contained elevated levels of lead at a concentration of 0.0179 mg/L. (This sample was also sent to a second lab, which reported the lead concentration as <0.005 mg/L). This well was located in Hays. A treatment system was installed and the well was retested within several weeks. The lead concentration had been reduced to 0.0029 mg/L, well below the comparison value of 0.015 mg/L. All other data provided indicated no levels of concern related to lead contamination.
Many people described their drinking water as being red or leaving red stains. Black stains were also described.
In most of the columns in Table 4, iron is above the 0.3 mg/L secondary maximum contaminant level (sMCL). The EPA has determined sMCLs for substances that, at higher levels, can cause unpleasant characteristics in drinking water. These secondary MCLs are based solely on aesthetic considerations (taste, color, staining, etc.), and generally have no implications for human health. Red staining such as that described by the community is one of the unpleasant characteristics that high levels of iron can impart to drinking water. Others include turbidity and unpleasant taste (van der Leeden, Troise, and Todd, 1990). Iron can also leave deposits on food and stain plumbing fixtures and laundry when there is more than 0.3 ppm in the water (van der Leeden, Troise, and Todd, 1990).
At concentrations in excess of its sMCL of 0.05 mg/L, manganese can produce black stains. Because the range of values for manganese in domestic wells at Fort Belknap (Table 4) ranges from less than 0.005 to 1.36 mg/L, black staining is also likely to be a major problem in some homes.
People also described steamy or cloudy-looking water when first poured from the tap, which cleared up after sitting for a while.
Water may come out of the tap looking steamy or cloudy if it has sediment (solids) suspended in it or if a lot of air is put into the water as it leaves the tap (aerator). If the water is allowed to sit for a while, the cloudiness should go away, either because the air re-dissolves or the sediment settles. If the problem is related to solids, treatment systems are available to remove them.
People described a white scale that formed in their water containers over time.
A number of substances can combine to produce scale. These substances include calcium, carbonate, bicarbonate, magnesium, nitrate, silica, and sulfate. Sodium in the water can accelerate scale formation (van der Leeden, Troise, and Todd, 1990). Although scale does not pose a danger to the health of someone drinking the water, it can be very destructive if allowed to accumulate in pipes, water heaters, dishwashers, etc.
To prevent the most common scale problems (calcium and magnesium salts), salts are removed from the water using two primary methods: ion exchange and precipitation. Ion exchange water softeners replace the ions, which are calcium and magnesium, causing the "hardness," with sodium. This approach can cause problems for people on low-sodium diets. Precipitation water softeners do not put sodium in the water, but they are far more complex to maintain than the simple ion exchange systems (Corbitt, 1990).
Several people mentioned that their water tasted "bad."
Bad taste, like the staining discussed previously, is another unpleasant characteristic that certain substances can impart to drinking water when those substances are present at levels greater than their sMCLs. Iron, manganese, sulfate, nitrate, and TDS are a few of the substances that can cause water to taste bad (van der Leeden, Troise, and Todd, 1990). All of these substances were present above their individual sMCLs, thus accounting for the bad taste that residents experienced. It should be noted that bad taste alone, although unpleasant, does not indicate that the water is unsafe to drink.
Another concern about the drinking water on the reservation was biologic contamination (by bacteria or other microscopic organisms).
For several years, King Spring has been posted as a biologic hazard. The contamination is most likely a natural result of wildlife activity in the area. Other biologic contamination issues on the reservation are related to monitoring and chlorination problems with the Jenny Grey, Lodge Pole Elementary School, and Hays/White Cow water systems in late 1995 (MAP, 1996). The Fort Belknap Community Council has since replaced the water plant manager. EPA water quality staff indicated that the routine monitoring results have recently been improving.
Biologic contamination of drinking water can lead to very serious health problems, including diarrhea and vomiting. To prevent waterborne disease outbreaks, maintenance of the drinking water plant is very important.
People were concerned about the tailings in the King Creek drainage and how far the tailings had been washed downstream over time.
The tailings in King Creek were the result of historic mining at the Little Ben and August mines, beginning in the early 1980s and existing until 1993. ZMI removed the tailings stored above the Cumberland Dam; however, some tailings remain in the drainage below the Cumberland Dam where, over the years, they have been washed. Table 5 presents a summary of all rock and tailings data available for ATSDR's review. These levels are not of concern, even though a few of the comparison levels are exceeded.
These levels are not of concern because it is unlikely that a child would regularly eat significant amounts of soil from these contaminated drainages. All of the comparison values listed in Table 5 are based on the assumption of chronic (long-term) exposure to a child who eats an average of 200 milligrams (mg) of contaminated soil every day. Because of the limited access to these tailings, these assumptions significantly overestimate both how much and how often soil from this area might be eaten by local children.
Several people were concerned about the use of Ruby Gulch tailings in construction of the Bear Gulch Road.
The Bear Gulch Road was not built using tailings material from the Ruby Gulch. A relatively small amount of the tailings were used for some maintenance activities during construction. The tailings were chemically tested before use to determine if they would leach metals or other harmful chemicals as they weathered. The results of the tests indicated that there would be no problem using the tailings (ATSDR, 1996a). In addition, the areas where the tailings were used have since been encapsulated with additional gravel and paving materials, greatly reducing the potential for any exposure to them.
Concern was also expressed about loss of flow in several of the drainages from the south onto the reservation.
The EIS discusses the diversion of surface water as a result of mining disturbances in Sections 3.2.3.1 and 4.2.3.4. Impacts from the Landusky mine include a significant impact (loss of 16% of the watershed) to King Creek resulting from of activities at the Gold Bug and Queen Rose pits. These activities produced a lesser impact to Swift Gulch, a tributary to South Bighorn Creek, which joins with King Creek to become Little Peoples Creek. Impacts from the Zortman mine are limited to a 0.6% loss of flow to the Lodge Pole Creek, and Beaver Creek has not been affected by current ZMI activities and would not be affected by any proposed expansion activities (DOI, 1996).
People are concerned about decreasing numbers of all types of fish and wildlife.
In the past, the tailings in the King Creek drainage adversely affected beaver and fish populations. Major rainstorms resulted in large quantities of tailings being washed downstream over a short period of time, causing a catastrophic loss of habitat for beaver and other wildlife (USFWS, 1974; Morrison-Maierie, 1979). The removal of the majority of the tailings from the drainage by ZMI has greatly reduced this problem.
An aquatic study of the southern portion of Fort Belknap was included in the recent consent decree as a supplemental environmental project. This study may provide more current information about the potential for impacts on wildlife as a result of the historic and current mining operations (EPA, 1996).
People are concerned about damage to vegetation resulting from the overspray of the cyanide solution used on the heaps.
There is no vegetation in the immediate vicinity of the heap leach piles. Once the cyanide has entered the air, it becomes a gas (hydrogen cyanide). Hydrogen cyanide gas is not removed from the air by water in the form of rain or snow, nor as a result of touching a surface, such as trees, grasses, etc. As a result, cyanide may be transported over long distances. Eventually, the hydrogen cyanide reacts with particles found in the atmosphere to form water, carbon dioxide, and nitric oxide (ATSDR 1995b).
People were concerned about reports of damage to vegetation that resulted from land application of cyanide solution.
Vegetation was damaged in the mid-1980s during land application of cyanide solution. The cyanide in the solution was destroyed, or neutralized, with calcium hypochlorite before land application (ATSDR, 1996b). The reaction between the two substances caused a gas to form that was damaging to the vegetation. Calcium hypochlorite is no longer used to neutralize the cyanide solution; it has been replaced with hydrogen peroxide, which does not damage vegetation.
Residents of the reservation have expressed concerns about various aspects of air quality, including emission of lead or hydrogen cyanide from the site.
There is no evidence in the air data reviewed by ATSDR that people from the reservation or anyone else, other than employees at ZMI, could be exposed to any air contamination (including particulates, lead, or hydrogen cyanide) at levels of health concern. Because ZMI has an employee health monitoring program, which includes cyanide safety training, respiratory fit-testing, and maintenance components, exposure of employees to air contamination at levels of health concern would not be expected.
VI. PUBLIC HEALTH IMPLICATIONS
The medical conditions reviewed in this section were identified as concerns by members of the communities, who participated in the public health availability sessions held in Hays, Lodge Pole, Malta and Landusky. Many of the concerns expressed by the community were also expressed by the Fort Belknap Community Council and the tribal environmental department in the initial discussions held with the Council.
Several individuals were concerned that one or more of the chemicals identified may be associated with their medical conditions, including reproductive cancers, lymphoma, thyroid cancer and thyroid conditions, diabetes, and arthritis.
None of the identified chemicals of concern at this site are known or suspected causes of the diseases or disorders (e.g., cancer, arthritis, diabetes, hepatitis, or respiratory and reproductive problems) identified as community health concerns at this site. ATSDR representatives reviewed the environmental data and the IHS reports to identify any possible links. None were identified.
The known or suspected risk factors for these diseases follow:
Cervical cancer - Known risk factors include early (before age 16) sexual intercourse, early first pregnancy, multiple sex partners, and venereal disease. Involvement of a sexually transmitted virus is suspected.
Uterine cancer - Major risk factors include estrogen exposure without a proper balance of progestins; estrogen-secreting tumors (for example, ovarian); advanced liver disease; menstrual cycles without ovulation; and obesity. Uterine cancer is the most common malignancy (cancer) of the female genital tract in the United States. Approximately 80% of cases occur after menopause; less than 5% are diagnosed before age 40.
Ovarian cancer - This cancer is more common in industrialized countries among childless women who experience "incessant (continuous) ovulation." Less than 5% of ovarian cancers are hereditary. Unknown physical, chemical, or dietary products may be contributing factors.
Prostate cancer - The causes of this cancer are unknown. Risk for prostate cancer is lowest for single men; married, widowed, and divorced men (in that order) have a greater risk. High rates are reported in loggers, chemists, farmers, textile workers, painters, rubber tire workers, and workers exposed to cadmium. Also, there is limited evidence that suggests an association between prostate cancer and herbicide spraying by agricultural and forestry workers. Risk is highest in Sweden, intermediate in the United States and Europe, and lowest in Taiwan, Japan, and among the Jewish population.
Lymphoma (Non-Hodgkin's) - This disease is associated with viruses (such as human immunodeficiency virus [HIV] and Epstein-Barr virus) and immune deficiency states such as acquired immunodeficiency syndrome (AIDS), organ transplants, congenital immunodeficiency syndromes, and autoimmune disorders that impair the body's ability to fight infections. Some studies have shown an association with use of phenoxy herbicides, while others have not.
Thyroid cancer - This type of cancer is associated with radiation exposure after a long latency period (5-50 years; average: 25 years); hereditary factors; and chronic thyroid-stimulating hormone elevation. The risk of thyroid cancer increases with age; women are affected 50% more often than men.
Thyroid problems - Goiter may be caused by inadequate dietary intake of iodine, defects of thyroid hormone production, or ingestion of goitrogens (such as turnips) that contain antithyroid substances. The causes of hyperthyroidism and hypothyroidism are not completely understood, but both are probably autoimmune diseases.
Arthritis - Some forms are associated with infection by nematodes (filariasis), bacteria (gonorrhea, rheumatic fever, Lyme disease, and pyrogenic and suppurative arthritis), and viruses (rubella, mumps, HIV [AIDS], and hepatitis B). The cause of many forms is unknown. Rheumatoid arthritis is probably an autoimmune disease.
Degenerative osteoarthritis - The cause is unknown. However, risk factors include congenital joint abnormalities; virtually any disease process that alters the normal structure and function of the hyaline cartilage (for example, rheumatoid arthritis and gout); and acute or chronic trauma (including fracture) to the hyaline cartilage (padding in the joint) or tissue surrounding it (for example, by prolonged overuse of a joint, as in certain occupations such as foundry work, coal mining, and bus driving).
Diabetes - Insulin-dependent diabetes mellitus (IDDM) results from a genetically conditioned, immune-mediated, selective destruction of >90% of the insulin-secreting beta cells of the pancreas. Non-insulin-dependent diabetes mellitus (NIDDM) is commonly associated with obesity, but genetic factors appear to be major determinants of the insulin resistance that is required for the development of NIDDM.
Several questions were raised about rashes described as small pimples and "very itchy" and rashes that were burning, itchy, and caused dry skin. Concerns were expressed that the rashes might be associated with exposure to surface waters.
Excessive swimming can lead to chronic dryness, burning, and itching of the skin. It is entirely possible that frequent bathing in some of the area surface waters that have very high levels of dissolved solids could produce dermal effects. However, it is not clear that these dermal effects, if they occurred, would correspond to the rashes described by the petitioners.
Itching may also accompany a primary skin disease or dry skin, and persistent scratching may produce redness, papules (bumps), and crusts along scratch lines. Bathing can aggravate generalized itching, especially if the patient has dry skin. Many drugs, especially barbiturates, such as sleeping pills, seizure medicine, and salicylates, such as aspirin, can cause itching. Itching can also be caused by poison ivy and certain other plants.
Women of child-bearing age were concerned about the relationship between the chemicals at the mine and the number of miscarriages and tubal pregnancies among reservation residents.
None of the chemicals at the mine are plausible causes of miscarriages or tubal pregnancies in women on the reservation.
Spontaneous abortions (miscarriages) are more common than they are generally perceived to be. About 20-30% of women bleed or have cramping sometime during the first 20 weeks of pregnancy, which, in some cases, may represent occult spontaneous abortions, and 10-15% have clinically recognizable spontaneous abortions. About 85% of spontaneous abortions occur in the first trimester and tend to be related to fetal causes such as chromosomal abnormalities and developmental abnormalities. Those occurring in the second trimester are usually related to maternal factors such as congenital or acquired abnormalities of the cervix or uterus; hypothyroidism; diabetes mellitus; chronic nephritis; acute infection; use of cocaine, especially crack; and severe emotional shock.
Generally, tubal pregnancies represent less than 1% of all diagnosed pregnancies, and about half of those are caused by a previous tubal infection. The chances of a tubal pregnancy increase with previous tubal disease, ectopic pregnancy (10-25%), exposure to diethylstilbestrol, or induced abortion. The incidence of tubal pregnancy is higher, and is rising, in minority populations.
Residents asked if excessive tiredness or fatigue could be associated with any of the chemicals identified as used by the mine.
The contaminants identified are not likely to cause excessive tiredness or fatigue. However, excessive tiredness and fatigue can be caused by the chronic anxiety that may be associated, in this case, with fear of potential exposures to chemical contaminants, the possibility of the mine closure and continuing layoffs, long working hours, and driving long distances.
A resident asked about the risks of being infected with hepatitis B.
The incidence of hepatitis is elevated in some areas of the Indian population. However, from the agency's review of health data collected at the Fort Belknap reservation, the risk of being infected with hepatitis B is about the same as that for any citizen in the state of Montana. In North America, the prevalence of hepatitis B carriers is less than one half of one percent, but that average will be higher or lower for specific subpopulations. The disease is caused by a virus (hepatitis B virus) that may be transmitted by sexual contact, transfusions, and hypodermic needles shared by drug users. It may also be passed from mother to infant. Less common causes include viruses such as infectious mononucleosis and leptospirosis.
A concern was expressed during the public health assessment process about many "unconditional statements" regarding health risks to the tribes that are based on unreliable information or incomplete analysis.
The responses provided to the questions from community members about specific diseases are based on current toxicologic and environmental information related to the particular disease. The health analysis considered the site-related information to determine if there are plausible environmental causes for specific health conditions, or plausible association with the site-related chemicals. Health outcome data were collected from Indian Health Service to identify disease categories provided by IHS. Discussions were held with the state department of health to verify the prevalence of the diseases of concerns in Hill, Blaine, and Phillips counties. In reviewing the settlement of the water quality lawsuit as related to health issues, ATSDR supports the community health evaluation that will be provided as a supplemental environmental program (SEP) so that the incomplete data can be addressed.
A review of the morbidity (diseases) and mortality (deaths) data for the reservation indicated that the overall rates of diseases and deaths were similar to rates in the Billings, Montana, area and other IHS areas. The rates of hepatitis, AIDS, and tuberculosis on the reservation are also similar to rates elsewhere in the state of Montana (IHS, 1995; Engman, 1996)
ATSDR staff conducted a review of the available morbidity and mortality health data for the reservation to identify any possible links related to chemical exposures. The data sources included Fort Belknap Hospital, Inpatient Report for 1992 - 1995 (hospital discharges; days; and average length of stay by admission diagnosis recode and age groups); Fort Belknap Hospital, Contract Health Service Report for 1990 - 1993 (hospital discharges; days; and average length of stay by admission diagnosis recode and age groups); Fort Belknap Service Unit, Cause of Death By County of Residence for calendar year 1980 (IHS, 1996); and the Public Health Nursing Health Assessment of the Fort Belknap Reservation for calendar year 1981 (IHS, 1981). Also, the Division of Epidemiology within the state of Montana was contacted.
ATSDR's comparison values are screening values used to facilitate the initial selection of site-specific chemical substances, known as "contaminants of concern" (ATSDR 1992a). After the contaminants of concern at a site have been identified, they are individually scrutinized in more detail to determine whether, under site-specific conditions of exposure, they represent a realistic threat to human health. Although concentrations at or below ATSDR's comparison values may reasonably be considered safe, it does not automatically follow that any concentration above a comparison value will necessarily produce toxic effects. Comparison values are intentionally designed to be lower--much lower--than the levels that produced "no effects" in laboratory animals.
On the basis of the available water analyses and health outcome data, no adverse health effects are expected to result from drinking Fort Belknap well water. Private wells at Fort Belknap yield "hard" drinking water that is high in dissolved solids and sulfate, as reflected in the high values for specific conductivity, TDS, and sulfate. The highest levels of sulfate and TDS detected in Fort Belknap drinking water (private well #9) may be sufficient to cause a temporary cathartic effect (diarrhea) in some individuals, especially infants not accustomed to the local drinking water (National Academy Press, 1980). However, residents are generally unaffected by the laxative properties of such water because their systems have adapted to it.
The principal dissolved solids detected in drinking water, including iron, manganese, calcium, magnesium, and sodium, are all essential nutrients. Toxic effects related to dietary overload are rarely seen because blood levels of these essential elements are homeostatically controlled, that is, the rate at which they are absorbed increases when intake is low and decreases when intake is high (ATSDR 1992b). Although manganese levels exceeded comparison values in two private wells, ingestion of water from those wells is not expected to produce adverse health effects. Manganism, a neurologic disorder with symptoms similar to those of Parkinsonism, occurs in workers who chronically inhale large amounts of airborne manganese while working in mines, steel mills, and chemical industries (ATSDR, 1992b). However, manganism is not known to occur with oral exposure. No confirmed case of this disease has ever been reported to occur in humans after ingestion of manganese-contaminated drinking water.
Calcium and magnesium, which account for most of the hardness and alkalinity in drinking water, are not only relatively nontoxic, they are essential nutrients required in large amounts (several hundred milligrams per day). Calcium even reduces the absorption of toxic metals such as lead and cadmium. The value used to separate soft from hard water was derived from practical considerations of effects such as boiler scaling rather than from observations on human health. Soft water may actually pose a greater threat to human health than does hard water. Some studies have shown a correlation between soft water and higher rates of cardiovascular disease (National Academy Press, 1980).
It is not possible to say whether antimony in groundwater exceeded drinking water standards because the detection limit used (0.05 ppm) was higher than ATSDR's comparison value (MCL=0.006 ppm). It is possible to say only that, whatever the absolute levels, the maximum values were no more than eight times the MCL, if they exceeded the MCL at all. No data are available on the health effects, if any, of chronic oral exposure to such levels of antimony. Much larger, acutely toxic doses are highly irritating to the gastrointestinal tract and tend to induce vomiting, thereby limiting the occurrence of systemic effects (ATSDR 1992c). Most other toxicologic data on antimony are from studies of occupational inhalation exposure and have little or no bearing on low-level exposure via drinking water.
Although lead was found to exceed drinking water standards in a few isolated samples, these detections were not reproducible. Most individual measurements during this decade were less than 0.0005 ppm--well below the action level of 0.015 ppm. None of the confirmed levels of lead in well water represent any hazard to public health.
On the basis of monitoring data available to the agency, ATSDR has concluded that because of its "hardness" and high levels of TDS, the drinking water at Fort Belknap exceeds certain sMCLs based solely on aesthetic considerations, but does not pose any public health hazard to adapted populations.
Agency for Toxic Substances and Disease Registry (ATSDR), 1992a. Public Health Assessment Guidance Manual, U.S. Department of Health and Human Resources, Atlanta, GA 30333.
Agency for Toxic Substances and Disease Registry (ATSDR), 1992b. Toxicological Profile for Manganese. Department of Health and Human Services, Atlanta, Georgia 30333.
Agency for Toxic Substances and Disease Registry (ATSDR), 1992c. Toxicological Profile for Antimony. Department of Health and Human Services, Atlanta, Georgia 30333.
Agency for Toxic Substances and Disease Registry (ATSDR), 1995a. ATSDR Record of Activity, documenting discussions during ATSDR site visit to the Fort Belknap/ZMI area, dated 11/05/95.
Agency for Toxic Substances and Disease Registry (ATSDR), 1995b. Draft Toxicological Profile for Cyanide. Department of Health and Human Services, Atlanta, Georgia 30333.
Agency for Toxic Substances and Disease Registry (ATSDR), 1996a. ATSDR Record of Activity, documenting a discussion with Mr. Cordell Ringel, BIA Billings Office on October 3, 1996.
Agency for Toxic Substances and Disease Registry (ATSDR), 1996b. ATSDR Record of Activity, documenting a discussion with Scott Haight, BLM, on September 16, 1996.
Agency for Toxic Substances and Disease Registry (ATSDR), 1996c. ATSDR Record of Activity, documenting a discussion with Jay Sinnott, EPA Montana Office on September 17, 1996.
B&L Industries, 8/95. Fort Belknap domestic well data: 2 wells.
Bondar-Clegg (BC), 1989. ZMI hard rock (ore) analysis.
Casiato, D.A., and Lowitz, B.B., 1995. Manual of Clinical Oncology, Third Edition, Little, Brown and Company, New York, NY.
The Citizens' Environmental Laboratory (Red Thunder's data), 8/92. Limited surface water and sediment data.
Corbitt, Robert A., 1990. Standard Handbook of Environmental Engineering, McGraw-Hill, Inc., New York.
DOI, 1996. U.S. Department of the Interior, Bureau of Land Management (BLM) and State of Montana, Department of Environmental Quality, Hard Rock Bureau, 1996. Final Environmental Impact Statement, Zortman and Landusky Mines, Reclamation Plan Modifications and Mine Life Extensions, Volumes I & II. Engman., Telephone discussion with Ms. Eng, Montana State Epidemiologist regarding health conditions in Hill, Blaine and Phillips Counties, June, 1996.
Environmental Protection Agency (EPA), 1996. In the United States District Court for the District of Montana, Billings Division. United States of America, and the State of Montana versus Pegasus Gold Corporation and Zortman Mining, Inc., Civil Action No. 95-95-BLG-JDS and Gros Ventre Tribe, Assiniboine Tribe, Fort Belknap Community Council, and Island Mountain Protectors Association versus Pegasus Gold Inc., Pegasus Gold Corporation, and Zortman Mining Inc., Civil Action No. 95-96-BLG-JDS.
Feltis, 1983. Ground-Water Resources of the Fort Belknap Indian Reservation, North-Central Montana. Montana Bureau of Mines and Geology Memoir 53.
Fort Belknap Community Council (Fort Belknap), undated. Water Quality Plan 208 Project.
Fort Belknap Community Council, 1994 - 1996. Water Quality Surface Water Analysis Results.
Fort Belknap Utilities, 1994 - 1995. Includes data for the Jenny Gray Well (3090042), the Mission Subdivision (3090043), Lodge Pole Housing (3090047), White Cow Canyon (3090044), Mission School (3090043), Lodge Pole Elementary (3090046), and Agency (3090041).
Grinell Agreement, 1896. Congressional Record, 54th Congress, 1st Session, Document No. 117. In the Senate of the United States, February 12, 1896, the Vice-President presented the following letter from the secretary of the Interior, transmitting an agreement made and concluded October 9, 1895, with the Indians of the Fort Belknap Reservation, in Montana, by William C. Pollock, George Bird Grinnell, and Walter M. Clements, commissioners appointed under the provisions of the Act of March 2, 1895.
Hydrometrics Inc., 4/95. Analyses Summary for wells TP-1 to TP-4 and the Zortman Community Well Z-8A).
Indian Claims Commission, Undated. THE BLACKFEET AND GROS VENTRE TRIBES OF INDIANS vs THE UNITED STATES OF AMERICA, Docket No. 279-C and The FORT BELKNAP INDIAN COMMUNITY vs THE UNITED STATES OF AMERICA, Docket No. 250-A, Plaintiffs' Requested Findings of Fact and Brief, Volume III of V, Land, Mineral, Pollution and Timber Findings.
Indian Health Service, 1990 - 1996. Domestic well data.
Indian Health Service, 1993. Surface water data: 4 samples.
Indian Health Service, 1995. Fort Belknap Hospital - Inpatient Report, Hospital Discharges, Days, and Average Length of Stay By Admission Diagnosis Recode and Age Groups (1992 - 1995), Fort Belknap Hospital - Contract Health Service Report, Hospital Discharges, Days, and Average Length of Stay By Admission Diagnosis Recode and Age Groups (1990 - 1993), Fort Belknap Service Unit -Cause of Death By County of Residence (Calendar Year 1980).
Indian Health Service, 1981. Public Health Nursing Health Assessment of the Fort Belknap Reservation
The Merck Manual of Diagnosis and Therapy, 1992. Sixteenth Edition (Robert Berkow, MD, Editor-in-Chief), Vol. I: General Medicine and Vol. II: Specialties, Merck & Co. Inc., Rahway, N.J.
Midwest Assistance Program (MAP), 1996. Fort Belknap Agency Water Treatment Plant Trip report dated March 17, 1996, and attachments.
Morrison-Maierie, Inc., 1979. Mill Tailings Investigations, Little Peoples Creek Drainage, Fort Belknap Indian Reservation, Montana. Prepared for U.S. Department of Interior, Bureau of Indian Affairs, Billings Area Office.
Morrison Knudsen, 1993a. Preliminary Assessment, King Creek.
Morrison Knudsen, 1993b. Site Inspection Analytical Results Report, King Creek.
National Academy Press, 1980. Drinking Water and Health, Vol. 3, Washington, D.C.
Pegasus Gold, 1993. Letter to Mr. Duncan Adams from John Fitzpatrick dated October 26, 1993.
Storet data base report 95/06/06 for wells TP-1 to TP-4 and Z-8A.
TEAM Data 9/95. Results of analysis of 6 samples: 2 streams, 2 domestic wells, 2 springs.
U.S. Bureau of Census, 1992 Tiger Files
U.S. Department of the Interior, Fish and Wildlife Service (USFWS), 1974. Memorandum from Larry C. Peterson, Fishery Management Biologist, to James Canan, Area Director, Billings Bureau of Indian Affairs Area Office, November 18.
United States Geological Survey (USGS) Data 1/95. Analytical results from 9 surface water samples (only used samples 1- 4 and 9, the others are too far north); 3 spring samples and 2 well (monitoring).
van der Leeden F., Troise, F.L., and Todd, D.K., 1990. The Water Encyclopedia, 2nd ed., Lewis Publishers: Chelsea, MI.
ZMI, 1997. Summary of Natural Water Quality Conditions. Prepared for Zortman Mining, Inc. Based on U.S. Geological Survey and Montana Bureau of Mines and Geology Research Documents. Found as Appendix A in Zortman Mining letter to Susan Muza, July 17, 1997.
Zortman-Landusky Water Resources Data Analysis Report, Draft Final, August 1995.
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