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PUBLIC HEALTH ASSESSMENT

FARMERS' MUTUAL COOPERATIVE
HOSPERS, SIOUX COUNTY, IOWA


SUMMARY

The Farmers Mutual Cooperative Company (FMCC) site is located on the northwest side of Hospersin Sioux County, Iowa. FMCC began operating as a farm cooperative in 1908. Companyoperations included handling, selling, and storing agricultural chemicals, including herbicides andfertilizers. In addition, grain fumigation had occurred on-site. In 1984, state investigations revealedvolatile organic compounds (VOCs) and herbicides in groundwater from three shallow city wellsadjacent to the FMCC site. The shallow municipal wells (PW-3, PW-9, and PW-10) werecontaminated with atrazine, alachlor, metolachlor, carbon tetrachloride, chloroform, and nitratesabove environmental media comparison values. On-site groundwater from monitoring wells alsocontained elevated levels of nitrates. Subsequently, the Iowa Department of Water, Air and WasteManagement, renamed the Iowa Department of Natural Resources (IDNR), requested that the citynot use the impacted wells in the community water supply system.

The FMCC site was proposed for inclusion on the National Priorities List (NPL) in June 1988 andwas listed in August 1990. Groundwater contamination is the main concern at this site. Afterreceiving input from the community, EPA and IDNR selected natural attenuation and groundwatermonitoring with a drinking water contingency plan as the final remedy. Community concernsregarding the quality of the drinking water supply were expressed during the August 1994 publicavailability session. These concerns are addressed in this document.

The Agency for Toxic Substances and Disease Registry (ATSDR) and Iowa Department of PublicHealth (IDPH) conclude, based on review of available data and current conditions at the site, thatthe FMCC site poses no apparent public health hazard. Past exposure to site-related contaminantsoccurred, but adverse effects are not expected to result. In 1996, the city connected to the HospersRural Water System for a water supply. In 1997, the three shallow municipal wells were pluggedand permanently abandoned. Exposure pathways do not exist under current site conditions.

Recommendations made in this document will ensure that the remedial actions continue to protect human health. No further public health actions are required at this time.


BACKGROUND

A. Site Description and History

The Farmers Mutual Cooperative Company (FMCC) site is located along Highway 60 in thenorthwest section of Hospers, Sioux County, Iowa. Hospers is approximately 55 miles northeast ofSioux City, Sioux County, Iowa (Figure 1). The FMCC property includes approximately 6.2 acresof land along both sides of Highway 60 (Figure 2). Several businesses including the FMCC officeand various warehouses or outbuildings are located in the eastern portion of the site.4

FMCC began operating as an active farm cooperative in 1908. Since that time, several changes tothe FMCC facility and its operations have occurred. In the past, agricultural operations included afertilizer plant, an ammonia tank, grain storage and fumigation, agricultural chemical sales andstorage, fertilizer sales, loading and storage, and custom application of field chemicals such asammonia.4 The FMCC facility was purchased by the Farmers Cooperative Elevator Association(FCEA) of Sheldon, Iowa, in July 1989. Currently, agricultural operations onsite are limited to grain storage and the application of field chemicals.

Historically, Hospers obtained its public water supply from four shallow municipal wells (PW-2,PW-3, PW-9, and PW-10) located in the vicinity of the FMCC site (Figure 3). Some of these wellsare within 50 feet of the FMCC facility on land purchased by the city.4 Municipal Well PW-2 wasabandoned in 1981. Three deep municipal wells located in the southeast section of Hospers wereinstalled in 1982. And the water from the shallow and deep wells was blended before distribution. An additional deep municipal well was completed in 1989.

In February 1984, herbicides and VOCs were detected in the Hospers' water supply as a result ofcitizen complaints regarding the aesthetic quality of the water (later determined to be related togasoline contamination.) The Iowa Department of Water, Air and Waste Management (currentlythe Iowa Department of Natural Resources (IDNR)), further investigated Municipal Wells PW-9and PW-10. Groundwater sampling results indicated that the shallow municipal wells werecontaminated with site related constituents (herbicides) and gasoline related VOCs. In 1984, IDNRrequested that Hospers not use the three shallow municipal wells for a water supply.

The FMCC, in cooperation with EPA and IDNR, conducted a series of site investigations to identifypotential source areas and determine the extent of groundwater contamination. In January 1985,IDNR requested that FMCC to develop a work plan to address contamination. A contractor, E.A.Hickok and Associates, was hired by FMCC to conduct a site and groundwater investigation. Soiland groundwater sampling was conducted on the FMCC facility. Analytical results indicated thatsoil and groundwater samples were contaminated with herbicides and VOCs. As such, FMCC wasimplicated as the primary source of contamination.1

Groundwater investigations indicated that on-site groundwater was contaminated with herbicides(Atrazine, Cyanazine (Bladex), Metolachlor (Dual), and Alachlor (Lasso)), nitrates, and VOCs(benzene, carbon tetrachloride, chloroform, and 1,2 dichloroethane). In July 1986, IDNR prohibitedthe city from using the three shallow municipal wells. This restriction was to remain in force untilthe contaminated wells were corrected.4

In August 1986, IDNR directed FMCC to conduct a Remedial Investigation/Feasibility Study(RI/FS). In July 1987, IDNR issued a consent order to Hospers because the city was violating therestriction and using the contaminated wells. In April 1988, IDNR again reaffirmed its restrictionon the use of the three contaminated shallow municipal wells. At that time, Hospers only used thefour deep municipal wells for drinking water. Water samples taken from the distribution system andcommunity tap after April 1988 did not contain contaminants above comparison values.18 A draftRI/FS report was submitted to EPA in March 1989. The RI/FS was finalized in 1991.4 Anaddendum to the RI/FS was issued in 1992.5 Soil samples taken during the RI/FS did not containsite-related contaminants above EPA comparison values.

The site was proposed for inclusion on the National Priorities List (NPL) in June 1988 and becamean NPL site in August 1990. During the 1993 sampling events, groundwater from municipal wellsPW-3, PW-9, and PW-10 still contained atrazine, metolachlor, alachlor, and nitrates.

A Record of Decision (ROD) regarding groundwater contamination at the FMCC site was signed byIDNR on September 25, 1992, and by EPA on September 29, 1992. Soil contamination was notaddressed, and later investigations did not identify soil areas that required remediation. Fourremedial action alternatives (RAAs) were proposed by IDNR and EPA for groundwater at the site. The selected alternative (RAA number 2) involved natural attenuation and groundwater monitoringwith a drinking water contingency plan.7 The contingency plan involved blending water fromshallow and deep wells to reduce the concentration of contaminants to acceptable levels.

In 1993, Hospers requested use of the shallow municipal wells. This request activated the drinkingwater contingency plan. Test pumping indicated that nitrate would severely limit blending andtreatment for nitrate was cost prohibitive. In 1996, the city connected to the Hospers Rural WaterSystem for a water supply. In 1997, the three shallow municipal wells were plugged andpermanently abandoned.

During the August 16, 1994, site visit, Iowa Department of Public Health (IDPH) staff discoveredthat FCEA had moved all bulk chemicals from the Hospers facility to a facility in Sheldon, IA. Also, the building that once housed the fertilizer plant operations had been demolished and only theconcrete pad remained.

The gasoline related VOCs (benzene, toluene, ethylbenzene, and xylene) were addressed underIDNR's Underground Storage Tank Program, but were included in one herbicide related monitoringprogram. The gasoline related VOCs were detected in groundwater but only benzene was foundabove the federal maximum contaminant level (5 ppb). Benzene was detected in January 1996 andJuly 1996 at 548 ppb and 614 ppb, respectively. Benzene was not detected during the November 1997. In August 1998 benzene was detected at 343 ppb.

B. Actions Implemented During the Health Assessment Process

The City of Hospers plugged (1996) and permanently abandoned (1997) Municipal Wells PW-3, PW-9, and PW-10. For a water supply, Hospers has connected to the rural water system and uses the deep municipal wells.

C. Site Visit

On April 28, 1992, Brad Cudal, Rick Welke, and Brian McPartland from the IDPH ToxicSubstance Evaluation Program visited the site. The manager of the FMCC facility conducted a tourand answered questions. Areas of special interest were monitoring well locations and areas wherehistoric site operations occurred. We toured areas where fertilizer was stored and loaded for farmingoperations and where the herbicide loading area was located. Site access was not restricted. The siteis separated into two sections by Highway 60, which separates the east and west portions of the site. The highway travels from north to south. The surface terrain in both portions of the site is generallyflat.

The western section is larger than the eastern section. Its shape is similar to a large rectangle thatnarrows in the south to about 50 feet wide by 250 feet long (Figure 2). Grain is stored in variousbins near the southern tip, adjacent to Highway 60. An equipment storage building is located in thewest central portion of the site. A fertilizer storage and operations building is located in the centralportion, adjacent to Highway 60. Various unpaved roads were encountered. They were used foraccessing grain storage and other ongoing business operations on the site. Site vegetation in thewestern portion was sparse, but was present in most open areas.

The site's eastern section is about 400 feet long from north to south and about 250 feet long fromeast to west. This eastern portion encompasses several businesses, including the FMCC office, alumber yard, and various warehouses or outbuildings. Grass has been planted for landscapingpurposes around buildings, but most of the available ground space in this portion consists ofbuildings and pavement.

On August 16, 1994, three IDPH representatives conducted a site visit. On-site and off-sitemonitoring wells were located. The deep off-site municipal wells and shallow rural water wellswere also located. The area where fertilizer was stored and handled was dismantled and not inoperation. A concrete slab was the only remnant. Surface water runoff was not noted. All ruralwater and deep water municipal wells were located up-gradient and cross-gradient to the site.

IDNR indicated, in September 1999 discussions, that site conditions remain unchanged.

D. Demographics

Based on 1990 U.S. Census Data, 738, 663, and 526 people live within 1 mile, 0.5 mile and 0.25mile of the site respectively. The population of Hospers, is 643 according to 1990 census data. Thepopulation of Hospers is predominantly Caucasian and earn low to middle range incomes. Therewere 74, 64, and 53 children, under the age of six, living within 1 mile, 0.5 mile, and 0.25 mile ofthe site respectively. There are 2 schools within a mile of the site. They are Floyd Valley schooland St. Anthony's school. The Hospers school district enrolls about 600 students from Hospers andthe surrounding rural area. There are no hospitals or nursing homes within this area. Populationdata around the site is presented in Appendix A (Figure 4). Population statistics can provide anestimate of potential susceptible populations at risk that could be impacted by site contaminants (i.e., the very young and elderly).

E. Land Use

Land use near the site is predominantly agricultural and industrial. Land west of the site is mostlygrassland and prairie that drains into the Floyd River. It is also considered part of the flood plain. The Hospers residential area, businesses, and school district are located directly to the east andsoutheast. FMCC operates and owns a commercial business that comprises most of the day-to-dayland use directly on-site. It also occupies most of the commercial buildings located within the site'sboundaries.

A small meat packing company is located directly south of the site beyond the gravel road that runseast to west. Agricultural activities, specifically grain farming, are conducted north of the site. Most of the land use surrounding Hospers, IA is agricultural.

F. Natural Resource Use

Presently, the Hospers rural water supply system serves approximately 2000 people. Municipalwells supplying water are within a three mile radius of the site. The Hospers Municipal WaterDepartment draws groundwater from four deep wells located in the southeast section of the city. These wells are approximately 300 feet deep into the Dakota Aquifer. The shallow municipal wellsaffected by site contaminants (PW-3, PW-9, and PW-10) are not used and have been permanentlyabandoned. The Hospers Rural Water System uses eleven wells located 1.5 miles north of Hospers. Seven of these wells are considered shallow (depths ranging from 19-30 feet). The other four wellsare at depths ranging from 254-343 feet, and also draw water from the Dakota aquifer. Based onhistoric data, none of the deep municipal or rural water wells have ever been impacted by sitecontaminants.

The site's shallow sand and gravel aquifer is locally productive. Glacial till and shale units separatethe shallow sand and gravel aquifer from the Dakota Aquifer. Groundwater flow in the shallowaquifer is southwest and discharges to the Floyd River.

Between 1982 and 1988, shallow municipal wells PW-3, PW-9, and PW-10 were blended with water from three deep municipal wells because city drinking water tasted bad. After the city was prohibited from using the three contaminated shallow wells in 1988, the city of Hospers installed an additional deep well in 1989 to meet their water supply needs. Residential homes near the site with private wells were connected to the municipal water supply system prior to 1989. Based on reports referenced in the ROD, none of the private wells have been affected by site related contaminants.4

The FMCC site and the western part of Hospers are located on the flood plain of the Floyd RiverValley. The Floyd River is the main surface water body near the site. It meanders to the south nearthe west side of FMCC. The Floyd River is sometimes used for bullhead and channel catfish fishing, but not in the area close to the site.

G. Health Outcome Data

While it may be possible to use state health data bases to determine whether certain health effects arehigher than expected in greater Hospers as compared to the county and the state, exposure pathwaysdo not suggest a need to review of this data.

The state maintains health databases on several registries: Cancer Registry, Birth Defects Registry,Infant Mortality Database, and Tuberculosis (TB) Registry. Disability Prevention Programs (caseevaluation for low birth weights, infant deaths, etc.) are also maintained by the state. The statecancer registry has collected data since 1969. The birth defects registry has collected data since 1985.


COMMUNITY HEALTH CONCERNS

On August 16, 1994, an availability meeting was conducted by IDPH. In attendance were IDPHstaff, two ATSDR Region VII Representatives, and an IDNR representative.

Community members posed the following concerns:

  1. A couple voiced concern about the quality of the present municipal water supply. The man said that if his wife drank municipal water she experienced diarrhea, but hewas not affected. Other individuals did not express the same problem.

  2. Another individual asked a general question about the level of nitrates, nitrates that may be found in groundwater, and potential health effects if ingested.

During the availability session, other concerns regarding health were not raised by the public. The above concerns are addressed in the Community Health Concerns Evaluation section of this document.

This public health assessment was released for public comment on January 3, 1996, throughFebruary 7, 1996. During that period, IDPH sought written and oral comments regarding the healthassessment's findings, conclusions, and recommendations. No comments were received and thecounty sanitarian did not report any complaints or community health concerns during the publiccomment period. Though the official comment period has ended, any subsequent comments orinformation pertinent to the site and/or public health assessment will be considered for future healthassessments or health consultations. Any information suggesting that adverse health effects arerelated to exposure from contaminants at the site will be further evaluated for any indicated follow-up. Area residents will be notified of any health risk identified during subsequent investigations.


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The tables in this section list site related contaminants. These contaminants are evaluated in subsequent sections of this Public Health Assessment to determine whether exposure has public health significance. ATSDR selects and discusses these contaminants based upon the following factors:

  1. environmental concentrations of on-site and off-site contaminants;

  2. field data quality, laboratory data quality, and sample design;

  3. comparison of on-site and off-site concentrations with background concentrations, if available;

  4. comparison of on-site and off-site concentrations with health-based comparison values for 1) noncarcinogenic endpoints and 2) carcinogenic endpoints; and

  5. community health concerns.

In the following sections, the listing of a contaminant does not mean that it will cause adverse healtheffects from exposure.


The data tables include the following acronyms:
EMEG = ATSDR Environmental Media Evaluation Guide
CREG = ATSDR Cancer Risk Evaluation Guide
RMEG = ATSDR Noncancer Risk Media Evaluation Guide
MCL = EPA Maximum Contaminant Level
MCLG = EPA Maximum Contaminant Level Goal
MW = monitoring well
NA = not analyzed
ND = not detected
ppb = parts per billion (equivalent to microgram per liter, µg/L)
PW = public well

Comparison values for the public health assessment are contaminant concentrations in specific media that are used to select contaminants for further evaluation. EMEGs are media-specific values developed by ATSDR to serve as an aid in selecting environmental contaminants that need to be further evaluated for potential health impacts. EMEGs are based on noncarcinogenic health endpoints and do not consider carcinogenic effects. RMEGs are similar to EMEGs, in that they evaluate the noncarcinogenic effects of a particular chemical. RMEGs are derived using the EPA Reference Dose (RfD). The RfD is an estimate of a daily exposure to a compound that is unlikely to cause adverse, noncarcinogenic health effects. CREGs are media-specific values developed by ATSDR to serve as an aid in selecting contaminants for follow-up that are potential carcinogens. CREGs are based on EPA cancer slope factors which give an indication of the relative carcinogenic potency of a particular chemical.

Maximum Contaminant Levels (MCLs) represent contaminant concentrations that EPA or IDNRdeems protective of public health (considering the availability and economics of water treatmenttechnology) over a lifetime (70 years) at an exposure rate of 2 liters of water per day. While MCLsare EPA regulatory concentrations, EMEGs, CREGs, and RMEGs are ATSDR comparison values.

Tables I and II list on-site groundwater contaminants selected for further evaluation. Table III listsselected contaminants in off-site groundwater. Table IV lists selected contaminants found in theshallow municipal wells (PW-9 and PW-10) from 1984-1990, which are no longer in operation. Table V lists contaminants found in shallow municipal wells PW-3 and PW-10 from the 1993 pump test sampling.

INTRODUCTION

The FMCC conducted site investigations with the State of Iowa beginning in 1984. Stateinvestigations detected VOCs (1,2-dichloroethane, carbon tetrachloride, chloroform) and herbicidesin groundwater from three shallow municipal wells adjacent to the FMCC facility. A four-phasedsite investigation was conducted under the RI/FS. Additional groundwater pump tests for waterquality were completed. Monitoring well and soil sampling locations are shown on Figure 2. PhaseI investigations were completed in 1986 and involved the installation and sampling of fourmonitoring wells, surface water sampling, and soil sampling at suspected contaminant source areas. Phase II investigations were completed in 1989 and involved the installation of three additionalmonitoring wells, and sampling of all monitoring wells and the three shallow municipal wells. Anaquifer pump test was also performed. Phase III investigations were completed in 1990 andinvolved the installation of ten additional monitoring wells, and comprehensive sampling of allmonitoring wells and the three shallow municipal wells. Phase IV investigations were completed in1992 and involved the installation and sampling of four additional monitoring wells and thirteen soilborings in an area previously identified as having high levels of herbicides in groundwater.

Data in the following tables are from groundwater samples collected during the RI/FS and fromfurther IDNR sampling. The samples were analyzed for target compound list (TCL) organicchemicals, TCL inorganic compounds (metals), specific herbicides and total nitrates.

A. On-site Contamination

TABLE I.

ON-SITE GROUNDWATER, 1991* (ppb)**
Contaminant Sampling Dates/Concentrations Location Comparison
Value
1984-1988 1990
carbon tetrachloride 11-250 <5.0 MW-3 0.3 CREG / 5 MCL
chloroform <0.1-50 <5.0 MW-6 6 CREG / 100 MCL
atrazine 10-11 3.9-4.7 MW-3 3 MCL
alachlor <0.9-35 <0.1-1.0 MW-6 2 MCL
cyanazine 1.2-3.1 0.6-11 MW-4 MW-15 1 MCLG ***
total nitrate 84,000 NA MW-3 10,000 MCL
*Directed Remedial Investigation Feasibility Study, 1991
**ppb - parts per billion
MW - monitoring well
NA - not analyzed
***-MCLG -EPA maximum contaminant level goal


TABLE II

ON-SITE GROUNDWATER, 1993* (ppb)**
Contaminant Sampling Dates Comparison
Value
10/93 12/93 10/93 12/93
Concentrations Locations
atrazine 7.0 3.0 MW-16 MW-16 3 MCL
cyanazine 2.2 <0.2 MW-16 MW-16 1 MCLG ***
metolachlor 590 160 MW-31 MW-31 100 MCL
total nitrate 70,000 56,000 MW-30 MW-30 10,000 MCL
benzene 3.6 ND MW-6 all MWs 1 CREG
chloroform 8.3 ND MW-6 all MWs 6 CREG / 100 MCL
1,2-dichloroethane 15.3 ND MW-6 all MWs 0.4 CREG
*FMCC, Test Pumping Results, City Well Nos. PW-3, PW-9, and PW-10, Hospers, Iowa, 1993
**ppb - parts per billion
MW - monitoring well
ND - not detected
***-MCLG -EPA maximum contaminant level goal

B. Off-Site Contamination

TABLE III.

ATRAZINE LEVELS IN OFF-SITE GROUNDWATER, 1991* (ppb)**
Contaminant Concentration
(1990 Sampling Date)
Location Comparison
Value
atrazine6.7MW-173 MCL
atrazine10-11MW-83 MCL
*Directed Remedial Investigation Feasibility Study, 1991
**ppb - parts per billion
MW - monitoring well

C. Municipal Wells

TABLE IV

SHALLOW MUNICIPAL WELLS, 1991* (ppb)**
Contaminant Sampling Dates/Concentrations Location(s) Comparison
Value
1984-88 1990
carbon tetrachloride <0.2-66 <1.0 PW-9 0.3 CREG / 5 MCL
chloroform 0.4-4.0 <1.0 PW-9 100 MCL
atrazine 2.7-40 4.7 PW-10 PW-9 3 MCL
2.6 PW-10
alachlor 0.32-11 1.6 PW-10 2 MCL
cyanazine 0.15-1.7 1.1 PW-9 10 MCL
metolachlor 2.3-200 3.2 PW-10 100 MCL
total nitrate to 128,000 NA PW-3 10,000 MCL
*Directed Remedial Investigation Feasibility Study, 1991
**ppb - parts per billion
NA-not analyzed
ND--not detected
PW--public well


Table V.

Shallow Municipal Wells, 1993* (ppb)**
ContaminantConcentrationLocationComparison Value
alachlor2.6PW-102 MCL
atrazine5.0PW-33 MCL
metolachlor170PW-3100 MCL
total nitrate49,000PW-310,000 MCL
*FMCC, Test Pumping Results, City Well Nos. PW-3, PW-9, and PW-10, Hospers, Iowa, 1993
**ppb - parts per billion
PW--public well

D. Toxic Chemical Release Inventory

Emissions from surrounding facilities may contribute an additional environmental burden to anearby population and FMCC site. Therefore, IDPH staff searched the Toxic Chemical ReleaseInventory (TRI) data for the years 1987 through 1992, and early 1993. The TRI containsinformation on estimated annual releases of toxic chemicals to the environment (via air, water, soil,or underground injection). These releases can be routine releases, spills and other accidentalreleases, or occasional releases from normal facility operation. Toxic chemical release informationis submitted to the EPA by industries with 10 or more full-time employees, as mandated under theEmergency Planning and Community Right-to Know Act of 1986. The TRI did not identify any nearby hazardous substance releases that may be affecting the area.

E. Quality Assurance and Quality Control (QA/QC)

In preparing this public health assessment IDPH staff assumes that information provided in thereferenced documents was prepared from adequate QA/QC directed chain of custody procedures,laboratory procedures, and data reporting. The RI/FS contained laboratory data validation reportswith appropriate quality assurance and quality control protocols.

The validity of the analyses and conclusions of this public health assessment are determined by the availability and reliability of the referenced information.

F. Physical and Other Hazards

The August 16, 1994, site visit revealed no physical hazards at the Farmers Mutual Cooperative Company site.


PATHWAY ANALYSIS

The pathway analysis section is where health assessment personnel evaluate environmental andhuman components to determine whether persons have been exposed to contaminants from the sitein the past, present, or potentially in the future. A completed exposure pathway consists of thefollowing five elements: a source of contamination, transportation of the contaminant through anenvironmental medium, an exposure point, a route for human exposure, and an exposed population.

A potential exposure pathway has at least one element missing. Potential pathways indicate thatexposure to a contaminant may have occurred in the past or may occur in the future. An eliminatedpathway means that data and information from the site connotes that past, present or future humanexposure to site related contaminants will not occur from a particular environmental medium. Thediscussion that follows identifies the completed, potential, and eliminated pathways at this site.

A. Completed Exposure Pathway

Table VI.

Completed Exposure Pathway
PATHWAY NAME EXPOSURE PATHWAY ELEMENTS TIME/
STATUS
ENVIRONMENTAL MEDIUM POINT OF EXPOSURE ROUTES OF EXPOSURE EXPOSED POPULATION
Site Shallow municipal well water Community tap water Ingestion,
Inhalation,
Skin Contact
Hospers area residents Past/
Completed

Shallow Municipal Wells:

Groundwater from the shallow municipal wells PW-3, PW-9, and PW-10 contained VOCs andherbicides at concentrations above comparison values. Prior to April 1988, drinking water forHospers was supplied by blending groundwater from deep municipal wells and shallow municipalwells. Although contaminated groundwater from the shallow municipal wells was previouslyblended with other uncontaminated sources, it is expected that the blending process reducedcontamination to acceptable levels. People using the municipal water were exposed to relatively lowlevels of contamination through ingestion, inhalation, and dermal contact. During that time,monitoring results of the community water supply were in compliance with existing regulations. Adverse health effects were not reported from past exposures. After 1988, the city discontinuedusing the shallow municipal wells.

Other Environmental Media:

Based on information and data from site investigations and the RI/FS (with addendum), completedexposure pathways for surface and subsurface soils, surface water, sediment, air, and consumable biota have not been identified.

B. Potential Exposure Pathways

Potential exposure pathways do not exist at the FMCC site. The use of the Hospers Rural WaterSystem for a water supply and plugging and permanently abandoning the shallow municipal wellshas effectively eliminated current and future exposures.

Private Wells:

If new private wells are installed in the plume of groundwater contamination, people using thecontaminated water could be exposed through ingestion, inhalation, and dermal contact. Privatewells are not used for household purposes in the immediate vicinity of the site.4 It is extremelyunlikely that a private well would be installed in the plume of contamination.

C. Eliminated Exposure Pathways

Surface and Subsurface Soils:

There are no past, current, or future indicated pathways in which humans could be significantlyexposed to site-related contaminants from surface and subsurface soils. Soil samples taken duringthe RI/FS were not above comparison values.

Sediment:

There are no past, current, or indicated future pathways in which humans could be significantlyexposed to site-related contaminants in Floyd River sediments. Based on available data, sedimentsin the Floyd River have not been impacted by site contaminants.4

Surface Water:

Surface water located about 525 feet west of the site, in the Floyd River, was sampled from 1984-1985. Sampling results for carbon tetrachloride and chloroform measured <0.2-91 µg/L and <0.2-9.0 µg/L, respectively. Subsequent 1990, 1991 and 1996 sampling did not reveal any significantlevels of these volatile organic compounds.4,5 According to area residents, people do not frequentlyvisit the stretch of the river near the site.

Consumable Biota:

Based on the RI/FS and Addendum, consumable biota from the Floyd River are not considered aviable pathway of exposure to site-related contaminants. This area of the river is not conducive for sport fishing.4,5


PUBLIC HEALTH IMPLICATIONS

In this section, the potential health effects in exposed people to specific contaminants are discussed,state and local databases are evaluated, and specific community health concerns addressed. Chemicals released into the environment do not always result in human exposure. Human exposureto a chemical can only occur if people come in contact with the chemical either by ingestion (eatingor drinking a substance containing the chemical), inhalation (breathing air containing the chemical),or by dermal absorption (skin contact with a substance containing the chemical).

To understand the type and severity of health effects that may be caused from exposure to a specificchemical, several factors related to the interaction of the chemical with the individual must beconsidered. Such factors include the amount of chemical, or dose, to which a person is exposed, thefrequency (how many times) and duration (length of time) of exposure, the route the chemical entersthe body (ingestion, inhalation or skin absorption), and the multiplicity (combination of chemicals)of exposure.

Health effects are also related to such characteristics as age, sex, nutritional and health status, lifestyle, and family traits. All of these characteristics may influence how a specific chemical isabsorbed (taken up by the body), metabolized (broken down by the body), and/or excreted(eliminated from the body).

To determine the possible health effects produced by specific chemicals, ATSDR considers physicaland biological factors as well as a variety of other information, such as scientific literature, researchreports, and reports from other federal agencies.

To evaluate health effects, ATSDR has developed Minimal Risk Levels (MRLs) for contaminantscommonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to acontaminant below which noncancer health effects are unlikely to occur. MRLs are developed foreach route of exposure, such as ingestion and inhalation, and for the length of exposure, such asacute (less than 14 days), intermediate (15 to 364 days), and chronic (greater than 365 days). ATSDR presents chemical specific MRLs in respective Toxicological Profiles. The chemical-specific profiles provide information on health effects, environmental transport, human exposure,and regulatory status. Also, EPA develops Reference Doses (RfD) for chemicals that estimates asafe daily exposure level. Exposures above an RfD may result in noncancerous, adverse healtheffects. Toxicological Profiles and other references used in the preparation of this public healthassessment are listed in the reference section.

Children's Health Section:

Based on the information reviewed for this public health assessment, it is unlikely that children wereexposed to unacceptable concentrations of site related constituents from FMCC in the past. Eventhough nitrates were detected in drinking water, the blending process would likely have reducedconcentrations to acceptable levels. Further, no nitrate related diseases were reported for thiscommunity while the wells were in use. IDPH has not identified any current or future exposure scenarios for children at the FMCC site.

A. Toxicological Evaluation

Herbicides and VOCs

Prior to 1988, groundwater from three shallow municipal wells (PW-3, PW-9, and PW-10) wasblended with groundwater from deep municipal wells to achieve a level of water quality which wasaesthetically appealing to consumers. Groundwater sampling efforts identified contamination(VOCs, herbicides, and nitrates) in the shallow municipal wells at levels above comparison values. Contaminants from these wells, at low levels, may have been ingested by residents who drank waterfrom the municipal water supply system during this period. Samples taken from the distributionsystem and community taps during regularly scheduled monitoring events did not indicate that anycontaminants exceeded EPA drinking water standards.18 Dose calculations for acute and chronicpast exposures to VOCs and herbicides do not indicate that adverse health effects would occur tohumans at these levels.

Nitrates

Based on empirical calculations, exposure to levels of nitrates found in well PW-3 (at 49,000 ppb)exceeds the EPA's RfD. The drinking water standard set by the EPA is 45,000 ppb, measured asNO3, or 10,000 ppb, measured as NO3-N. These standards are equivalent. If water contaminated atthe highest level was the sole source of drinking water for infants, then they may be at increased riskfor methemoglobinemia. However since water was blended from several sources, it is unlikely thatinfants were consistently exposed to the maximum levels detected so we would not expect to see thishealth effect.

The drinking water standard was set primarily to avoid infant methemoglobinemia, also known asblue-baby syndrome. Methemoglobinemia is a reversible blood disorder that reduces the ability ofan infant's bloodstream to carry oxygen throughout the body. Water containing nitrate above thestandard should not be utilized when preparing infant formula or consumed by infants less than sixmonths old. The current drinking water standard is only based on non-carcinogenic healtheffects.13,14

Currently, contaminated groundwater from the three shallow municipal wells is not used in thecommunity water supply system. In 1996, the city connected to the Hospers Rural Water Systemfor a water supply. In 1997 the three shallow municipal wells were plugged and permanently abandoned.

B. Health Outcome Data Evaluation

None of the available health outcome data would provide information that could be useful inassessing past exposures. Moreover, no nitrate-associated illnesses were reported in infants when the contaminated wells were used.

C. Community Health Concerns Evaluation

Specific health concerns or questions from the August 1994 availability meeting that may be relatedto the site are answered in this section. The primary health concerns have been addressed as follows:

Concern #1:

A statement was made concerning the present municipal water that a man and his wife wereconsuming. The person said that if his wife drank municipal water she would experience diarrheaafterwards, but he could drink the water with no after-effects.

Answer #1:

It is difficult to implicate the community water supply as the cause of the diarrhea. No other individuals experienced the same problem. The process of establishing a water standard or guideline begins with a scientific assessment of the toxicity or risk to public health posed by the contaminant. Scientists typically make a series of safe or conservative decisions to determine the contaminant concentration in drinking water that is not expected to cause public health problems. Since the groundwater was blended to achieve the necessary dilution, it is unlikely that the contaminants listed at this site are the cause of the diarrhea.

There might be other compounds that could contribute to this problem. For example, elevated levelsof magnesium and sulfates in the groundwater could have a laxative effect. Consequently, werecommend that those individuals manifesting symptoms of diarrhea consult with their personalphysician.

Concern #2:

An individual asked about the level of nitrates in general, nitrates that may be found in groundwater,and the potential health effects if ingested.

Answer #2:

Low concentrations (up to 5 mg/L) of naturally occurring nitrate are found in some uncontaminatedgroundwater. Higher concentrations probably indicate a degree of pollution by fertilizer, manure,septic tank wastes, polluted surface waters, or other sources. Water containing nitrates above thestandard, as discussed earlier, should not be used for human consumption. EPA has indicated thatthere is insufficient information currently available to determine whether nitrate causes cancer inhumans. The current drinking water standard is based only on non-carcinogenic health effects.

Any information suggesting that adverse health effects are related to exposure from contaminants atthe site will be further evaluated to determine if any further follow-up activity is needed. Arearesidents will be notified of any health risks identified if subsequent investigations are performed.


CONCLUSIONS

ATSDR and IDPH conclude, based on data reviewed, that the Farmers' Mutual CooperativeCompany site in Hospers, IA can be categorized as a no apparent public health hazard. Thiscategory was selected because historical exposure occurred but was below levels of concern. IDPHand ATSDR will revisit the site if critical, new information becomes available.

The selected remedy for this site included natural attenuation; groundwater monitoring to determineeffectiveness; and a contingency plan if the impacted aquifer is used as a drinking water supply priorto restoration. However, in 1996, the city connected to the Hospers Rural Water System for a watersupply. The contaminated shallow municipal wells were plugged and permanently abandoned in1997. These actions effectively eliminated the exposure pathways.

Historically, people were exposed to VOCs, herbicides and nitrates in drinking water. The levels ofexposure to those contaminants are not expected to have resulted in adverse health effects.

Children's Health Conclusion:

Based on available information and data reviewed regarding children's exposure and ultimatelytheir health, we believe that no apparent public health hazard exists or existed for children. Becausehistorical exposure did occur, the site was categorized as a "No Apparent Public Health Hazard." IDPH and ATSDR will revisit the site if critical, new information becomes available.


RECOMMENDATIONS

  1. Continue the groundwater monitoring program to ensure that the remedy continues toprotect human health and the environment.

  2. If necessary, institutional controls should be considered to prevent the installation of wells for public and domestic purposes within the contaminated aquifer.

PUBLIC HEALTH ACTION PLAN

Based on the recommendations made in the health assessment, the following public health actionshave been or will be taken by ATSDR/IDPH and other governmental agencies:

A. Actions Undertaken

EPA and IDNR will continue to conduct groundwater sampling to monitor the effectiveness ofnatural attenuation.

EPA will review the FMCC site in 2000 to ensure that the remedy continues to protect human healthand the environment.

Presently, follow-up or other actions are not being implemented by ATSDR and IDPH on this sitebecause exposure to site-related contaminants is not occurring.

Future actions are not planned by ATSDR or IDPH at this time.


PREPARERS OF REPORT

IDPH Health Assessment Team

Russell Currier, DVM, MPH
Environmental Epidemiologist
Iowa Department of Public Health

Brad V. Cudal, M.D.
Environmental Specialist
Iowa Department of Public Health

Richard L. Welke
Environmental Specialist
Iowa Department of Public Health

Elena Babak, Ph.D.
Environmental Specialist
Iowa Department of Public Health


1999 IDPH Health Assessment Edit/Update

Karl V. Markiewicz, Ph.D.
Principle Investigator/Program Manager
Iowa Department of Public Health


ATSDR Regional Representative

Denise Jordan-Izaguirre
Senior Regional Representative
ATSDR, Region VII


ATSDR Technical Project Officer

Roberta Erlwein
Environmental Health Scientist
Division of Health Assessment and Consultation


CERTIFICATION

The Farmers Mutual Cooperative Company public health assessment has been prepared by the IowaDepartment of Public Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health assessment was initiated.

Roberta Erlwein
Technical Project Officer, SPS, RPB, DHAC


The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health assessment and concurs with its findings.

Richard Gillig
Director, DHAC, ATSDR


REFERENCES

  1. Eugene A. Hickok and Associates. Groundwater Quality Investigation of Farmers Mutual Cooperative Company. 1985.

  2. Eugene A. Hickok and Associates. Remedial Investigation Summary Report for the Farmers Mutual Cooperative Company. 1989.

  3. Iowa Department of Natural Resources. Farmers Mutual Coop Company, State Abandonedor Uncontrolled Site Registry, Site Information Package. Des Moines, IA. 1989.

  4. James M. Montgomery Consulting Engineers, Inc. Remedial Investigation/Feasibility Study for Farmers Cooperative Elevator Association, Sheldon, IA. 1991.

  5. Iowa Department of Natural Resources. Addendum to Farmers Cooperative ElevatorAssociation Remedial Investigation/Feasibility Study, Hospers, Iowa Facility. Des Moines, IA. 1992.

  6. Iowa Department of Natural Resources. Farmers Mutual Coop, Test Pumping Results, City Well Nos. 3, 9, and 10, Hospers. Des Moines, IA. 1993.

  7. Iowa Department of Natural Resources. Record of Decision for Farmers Mutual Cooperative Company Site, Hospers. Des Moines, IA. 1992.

  8. Agency for Toxic Substances and Disease Registry. Preliminary health assessment forFarmers Mutual Cooperative Company, Hospers, IA. Atlanta: US Department of Health andHuman Services, Public Health Service. 1990.

  9. Agency for Toxic Substances and Disease Registry. Review draft health assessment for Farmers Mutual Cooperative Company, Hospers, IA. Atlanta: US Department of Health and Human Services, Public Health Service. 1991.

  10. Agency for Toxic Substances and Disease Registry. Toxicological profile for carbontetrachloride. Atlanta: US Department of Health and Human Services, Public HealthService. 1989.

  11. Agency for Toxic Substances and Disease Registry. Toxicological profile for chloroform. Atlanta: US Department of Health and Human Services, Public Health Service. 1989.

  12. Dreisbach, R. Handbook of Poisoning, 12th Edition. Norwalk, CT: Appelton and Lange. 1987.

  13. Ellenhorn, M. Medical Toxicology. New York: Elsevier. 1988: Pages 844-851.

  14. National Research Council. Drinking Water and Health. Washington: National Academy of Sciences. 1977: Pages 229-231.

  15. Casarett & Doull's. Toxicology, The Basic Science of Poisons. Fourth Edition: Pergamon Press. 1991: Pages 821, 893-894.

  16. United States. EPA. Morgan, D.P. Recognition & Management of Pesticide Poisonings, Fourth Edition. Washington: GPO. 1989.

  17. Agency for Toxic Substances and Disease Registry. Toxicological profile for benzene. Atlanta: US Department of Health and Human Services, Public Health Service. 1993.

  18. Dohrmann, Keith. The SAS System, Results of Organics, Inorganics, and Nitrates, Hospers Municipal Water Dept. Des Moines, IA: IDNR. 1995.>/li>

APPENDIX A: FIGURES

Site Location Map
Figure 1. Site Location Map

Well Locations Map
Figure 2. Well Locations Map

FMCC Site Boundaries Map
Figure 3. FMCC Site Boundaries Map

Farmers Mutual Cooperative Company Population Data
Figure 4. Farmers Mutual Cooperative Company Population Data

Table of Contents

  
 
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