PUBLIC HEALTH ASSESSMENT
MID-ATLANTIC WOOD PRESERVERS
HARMANS, ANNE ARUNDEL COUNTY, MARYLAND
The Mid-Atlantic Wood Preservers Site (MAWP), located in Harmans, Anne Arundel County, Maryland, has been evaluated for potential health risks to on-site workers and the neighboring community. The MAWP facility has been operating since 1974, using a chromated copper arsenate (CCA) solution to treat wood. The treated wood is subsequently dried on a dripping pad. Drippings of this solution from treated wood during the drying process and an accidental spill of CCA in 1978 were identified as the sources of high levels of chromium, copper and arsenic in soil and groundwater in the site's vicinity. Nearby residents with private wells were connected to municipal water supplies shortly after groundwater contamination was discovered.
The Remedial Investigation, conducted in 1989, reaffirmed the presence of significantly elevated copper, arsenic and chromium in on-site soils. Past and current copper levels did not exceed health-based comparison values in soil or any other environmental media, and so was not evaluated further. Arsenic was present in off-site soils at much lower levels that nonetheless exceeded local background arsenic concentrations. The initial pollution of private wells downgradient from the site had been reduced by 1989 to very low levels or was not detected at all. A Record of Decision describing the proposed remediation plan was issued in December 1990 by the U.S. Environmental Protection Agency (USEPA).
Pathways of completed human exposure include current and past inhalation of fugitive dust and incidental ingestion of on-site surface soil from the treatment yard and storage yard. Surface soil contaminant levels are and were significantly higher at the site than in the adjacent areas. However, community access to the site is limited by a chain-link fence which surrounds it. Thus, direct contact with on-site soil is limited to MAWP employees and remediation workers.
Potential past and current incidental ingestion of off-site surface soil near the sewer outfall is also a pathway of concern due to elevated arsenic and chromium levels detected in this area. Community exposure to surface soil here is limited because the sewer outfall area is highly vegetated, and located in an isolated area.
Possible past exposure to hexavalent chromium in drinking water from private groundwater wells next to the site is also a concern. Contaminated wells were discovered immediately after an on-site chromium spill occurred in 1978. Until this incident, no groundwater samples had been taken since MAWP operations began in 1974. Therefore, if low-level chromium contamination existed prior to the spill, the maximum period of potential community exposure by this pathway would have been limited to 4 years. The one home well sampled was not used for drinking water.
Because concentrations of groundwater contaminants are now below health-based standards, and neighboring residents are no longer drinking local groundwater, future exposure through drinking groundwater is not expected.
This site is currently a public health hazard due to past and current exposure to chromium and arsenic in on-site surface soil. Long-term exposure to chromium poses a risk of cancer, liver and kidney disease, and exposure to arsenic poses a small cancer risk. However, initial remediation efforts reduced these contaminants to levels that do not present an urgent public health hazard. In addition, because remedial activity is currently underway, future exposure and consequent risk is expected to be eliminated. (NOTE: Since the time of this conclusion, the facility has ceased operations. Therefore, the concern about site workers, other than remediation workers, is no longer valid.)
The Maryland Department of the Environment (MDE) recommends that the cleanup strategy outlined in the Record of Decision be implemented as soon as possible, and that further community health concerns be addressed as they develop. On-site levels of chromium and arsenic should be cleaned up to acceptable levels. Off-site contamination should be more completely characterized. Long-term monitoring of air and water at the site, as proposed in the remediation plan, should also be carried out.
Long-term cancer surveillance of neighboring workers and residents is not recommended for several reasons. Potential excess cancer risk related to site contamination is relatively low as is the number of persons who could be exposed to these site-related contaminants. Furthermore, the opportunities for community exposure are limited by the characteristics of the site: a chain link fence surrounding the site, an isolated location, and heavy vegetation around the site. MAWP employees, who have had higher exposures to arsenic and chromium than the surrounding community, should notify their physicians about their exposures and the potential excess risk of cancer associated with these exposures.
Finally, as a precautionary measure, daily contact with surface soil from the sewer outfall adjacent to the site should be avoided. Regular activity in this area could result in exposure to arsenic detected in that area.
ATSDR's Health Activities Recommendation Panel (HARP) reviewed the information for the Mid-Atlantic Wood Preservers site and determined that the following actions are indicated.
- To protect MAWP workers from the potential toxic effects of exposure to chromated copper arsenate, MDE needs to notify the appropriate Maryland agency about site conditions so that MAWP managers and workers are informed of the regulations that should be followed to protect worker health.
- The community needs to be notified that the Public Health Assessment for this site is available for public comment. The notification should mention that, to minimize possible exposure to arsenic in soil, small children should not be allowed to play on a regular basis in the immediate vicinity of the sewer outfall. The outfall is located northwest of the site.
- That MDE's conclusion that additional health studies of nearby residents should not be done because they are unlikely to reveal cancers or birth defects that could be attributed to the site. However, MAWP workers, potentially receive much higher exposures to chromium and arsenic than neighboring residents. Therefore, MAWP workers should notify their physicians about their potential exposures and about the increased risk of developing cancer as a result of those exposures.
To ensure that actions recommended are implemented, a Public Health Action Plan was developed. To explore whether the MAWP was in compliance with regulations to protect workers from potentially harmful chemical exposures, MDE contacted the Maryland Occupational Safety and Health (MOSH) division of the Maryland Department of Licensing and Regulation. MOSH indicated that the MAWP premises were most recently inspected by MOSH staff as part of a routine, planned investigation on July 24, 1992. MOSH inspectors certified that the MAWP was in compliance with health and safety, and worker right-to-know regulations. Therefore, MDE is satisfied that workers were adequately protected from potentially toxic exposures to chromated copper arsenate. No further actions by MDE are necessary to fulfill the first HARP recommendation above because the facility is now closed.
To insure that samples were obtained from the highest zone of arsenic contamination, additional samples from shallow on-site soils and fill were taken by MDE's CERCLA's Response Division in April 1992 and by MAWP's contractor in June 1992. This sampling revealed that a wider area of shallow soils than previously thought had elevated arsenic levels. As a result, a greater proportion of the MAWP surface will be paved in accordance with the criteria established in the Record of Decision to reduce any potential human health risks from arsenic.
The public was notified of the availability of the public health assessment. Comments were received, and those comments, with a response to those comments, appears in the Attachment of this document.
Because the facility is now closed and plans for remediation of the site are sufficient to prevent human exposure, no further actions are warranted on this site.
Mid-Atlantic Wood Preservers (MAWP) is an active wood treating facility located at 7457 Shipley Avenue, near Dorsey Road, in Harmans, Anne Arundel County, Maryland 21076 (Figure 1).(1) The site was formerly undeveloped forested land and now is part of a mixed industrial and residential community. Gunther Transport Trucking Company is south of the site. An abandoned house, piles of construction rubble, and excavation equipment are located north of the site. There are a few other residences and light industries south of the site, along Shipley Avenue. Penn Central Railroad tracks border the eastern site boundary.
The site mainly consists of two impoundments, one on each side of Shipley Avenue. These unpaved dirt and gravel areas are approximately equal in size, together totaling 3.12 acres. The area to the west of Shipley Avenue is used as a storage yard for treated wood. The main processing plant, a storage shed, and additional storage space are located on the eastern side of Shipley Avenue. Access to both areas is limited by chain link fences which are locked when the facility is not operating.
The facility operated using a chromated copper arsenate (CCA) water-borne treating process to preserve wood. The 2-part process begins by pressure treating lumber in a housed processing plant. The wood is then moved outside to a concrete dripping pad and left to dry. From 1974, when the operation started, until 1981, the treated wood was not always left on a drip pad to dry. When placed in other areas of the site, excess CCA solution would drip directly onto the ground. In addition, a 1978 field investigation identified a spill from a CCA storage tank as the probable primary source of the soil and groundwater contamination. Approximately 3,000 gallons of CCA were reported to have spilled onto the ground through an overflow pipe when the storage tank was being filled in August 1978. Soon after the spill, groundwater contamination was discovered in a nearby residential well, and neighboring homes were then connected to the municipal water supply.
Several steps were taken to reduce contamination at the site. The concrete drainage pad for treated wood was modified to allow collection and subsequent reuse of waste CCA. In addition, the process was modified to allow a longer drying period for wood on the drainage pad. Between October 1979 and November 1980, 26 cubic yards of contaminated soil were excavated from beneath the CCA storage tank overflow pipe and replaced with clean clay soil.
The Site was proposed for inclusion on the National Priorities List in October 1984 and was finalized in May 1986. A Consent Order, under which Mid-Atlantic Wood Preservers, Inc. agreed to perform a Remedial Investigation and Feasibility Study (RI/FS), was signed in July 1986.
The detailed field investigation associated with the Remedial Investigation (RI) reaffirmed the presence of arsenic, chromium, and copper in on-site soils and slightly elevated levels of chromium in the groundwater. Samples taken prior to the RI found concentrations of copper, chromium and arsenic in Stony Run Creek surface water, but levels were within the normal range expected in a freshwater stream and, therefore, were not an environmental concern. These 3 metals were not detected in surface water samples taken as part of the RI.
The Feasibility Study (FS) analyzed several remediation options. The remedy selected involves enlarging and covering the concrete drip pad, and covering a large portion of the wood storage area with asphalt. These plans were finalized between September and November 1992. EPA conducted a public meeting regarding the plans in May 1993.
Maryland Department of the Environment (MDE) staff conducted a site visit on June 27, 1991, along with the USEPA's remedial project manager, Eric Newman. The MDE staff consisted of Carolyn Nunley from the Environmental Toxicology and Risk Assessment Division, and Sesh Lal and George Herald, project engineers from the hazardous Waste Division. The group met with the facility owner, Mr. Bernard Liedman, and was given a tour of the facility.
The facility was operating at a normal capacity. Process changes had been made to collect excess CCA drips from the concrete pad, the latter which will be enlarged and covered as soon as the remediation work plan is complete. The storage areas to be covered with asphalt were orderly and free of any evidence of excess CCA drippings. The entire area was enclosed by a chain-link fence, and there were no signs of trespassing.
In February 1993, the facility ceased operations. Although the MDE health assessment team did not visit the site after closure, other MDE staff did. The physical characteristics reportedly are not changed from the original site visit; however, the entire area of contamination is to be paved.
Harmans is located within two Census tracts. Tract # 7506 includes the Shipley Avenue area and most of the town. Tract # 7401.01 comprises Old Dorsey Road, and the Sandalwood and Ridgeview subdivisions. Approximately 1,199 people live in Tract #7506, and 15,893 were counted in tract #7401.01, according to the 1990 Census. The zipcode for Harmans is 21077. It is surrounded by the zipcodes 21076 to the south and west, and 21240 to the north and east.
Approximately 200 residences are located within a 1-mile radius of the MAWP site, 22 of which are within 2,000 feet of the property boundary. The closest residence is approximately 500 feet from the site. No other residences are in the immediate vicinity of the MAWP. Based on 1990 Census data, there are, on average, three occupants per dwelling in this area. Based on these figures, it is estimated that 66 people live within 2,000 feet, and 600 people live within one mile of the MAWP site. The estimated age of these residences is approximately 10-15 years. These homes are generally occupied by middle class families with a median household income of $47,819 per year (AACOPZ, 1991).
The Anne Arundel County 1990 Census estimates that 24.6% of these residents are under age 18. Approximately 66.6% are adults age 18 to 64, and 8.8% are age 65 and above. There are 2 schools in the area, each more than 1 mile away from the MAWP site.
The land in the immediate vicinity of MAWP is predominantly industrial or vacant. Immediately to the east of the site are the Penn Central Railroad tracks. Further to the east and northeast is vacant land which extends approximately 1 mile up to the Baltimore Washington International Airport. To the immediate south are more light industry and vacant land which extend approximately 1/4 mile up to Dorsey Road. South of Dorsey Road are several residential developments and more light industry. Immediately to the west of the site is Stony Run Creek, which is bounded by a swath of wooded, vacant land, 1,000 feet wide. To the west, on the other side of Stony Run Creek is a strip of vacant woods which separates the Creek from a large industrial park which is further to the west. To the north is a lumber storage facility, with vacant wooded land further to the north along Stony Run Creek.
Natural Resource Use
In 1984, seventeen domestic wells and 11 public supply wells were identified within a 3-mile radius of the MAWP site. It is estimated that the domestic wells serve about 65 people, and the 11 public supply wells serve a population of 75,000 people (NUS, June 1984). In addition, two more public wells within a three-mile radius of the site were under construction in 1984.
A more recent well inventory maintained by the Maryland Water Resources Administration (MWRA) identified 35 domestic and water supply wells within a one-mile radius of the MAWP site (Dames and Moore, 1990a). Only six of the 35 wells listed are downgradient from the site (i.e., in the direction of groundwater flow). Groundwater flows from the MAWP site to the west-northwest, and may trend more to the north to follow the confluence of Stony Run Creek (see discussion of Stony Run Creek that follows). The majority of the wells are located in the subdivision south of Route 176 and east of Route 170. The nearest well is located to approximately 0.5 miles north of the site. Even though this well is in the pathway of expected groundwater flow from the site, it is not used for drinking water.
Surface water runoff from MAWP drains into Stony Run Creek, located approximately 600 feet west of the site and bordered by a marsh-like wetland within 400 feet of MAWP. Stony Run Creek discharges to the Patapsco River near Elkridge, Maryland, approximately 4 miles downstream of MAWP. Use of Stony Run Creek is restricted to minor recreational activities such as canoeing and hiking along the water's edge. The Creek usually has a very low flow, which increases in the spring and summer. Community residents reported that, in the past, recreational fishers stocked the stream with small fish at the beginning of the each fishing season and fished from a bridge located on Shipley Ave (USEPA, 1990).
Since most of the MAWP site is paved with asphalt or crushed stone, vegetation and wildlife on the site itself is sparse to nonexistent. However, the surrounding area supports a wide variety of plant and animal species.
The Maryland Department of Health and Mental Hygiene (DHMH) is currently in the process of gathering cancer incidence data dating back to 1983. Comparative cancer incidence data for the local (zipcode or census tract), county and state is projected to be available sometime in the next two years. Cancer mortality data is available from DHMH through 1988.
The birth defects registry at the DHMH has data available from 1984 to 1988; however, the data are limited to 12 sentinel birth defects reportable by law.
Vital statistics (births and deaths) are compiled by the DHMH and are available from the early 1960's through 1987.
Community members have expressed a moderate level of concern about the site cleanup at a local community meeting held by USEPA and MDE on November 11, 1990. However, most of the concern has been focused on the timeliness of site remediation and the impact of the site on land values rather than on human health. Community members appear to feel that agency officials acted quickly in addressing their exposures to groundwater contamination (AACS, 1990). At the community meeting, residents recommended to USEPA that the design of the proposed new drip pad for CCA treated wood be modified to prevent soil contamination due to storm flooding of the pad. USEPA representatives were responsive to this suggestion (USEPA, 1990).
At the time the contamination was discovered, the State of Maryland and MAWP were being sued by the owner of the most affected drinking water well. The suit was settled out of court, and the homeowner moved out of the area (Dames and Moore, 1990b). Since that time, other residents have voiced little concern, with the exception of one resident who issued a formal complaint against MAWP in 1989 for a possible discharge of CCA from the MAWP site to surface and\or groundwater. The MDE investigated the facility and found no obvious violations. However, USEPA was notified of the complaint and a surface runoff survey was included in plans for additional monitoring at the site.
A Record of Decision (ROD) was issued in December 1990 by USEPA. In December 1991, USEPA issued an order directing the MAWP to select a contractor to implement the remediation design. The order became effective on January 29, 1992. MAWP has agreed to comply with this order. Once the final remediation design plans have been drawn up, USEPA held another community meeting to discuss the design plans with the public. Although the facility ceased operations in February 1992, the public meeting was held in May 1993. That meeting was to gather concerns and opinions about the remediation design. No health concerns were gathered at that time.
During the public comment release of this document, community health concerns were posed by community members. Those concerns, and a response to those concerns, appear in the Attachment of this document.