«MINNEAPOLIS, HENNEPIN COUNTY, MINNESOTA ST. PAUL, RAMSEY COUNTY, MINNESOTA EPA FACILITY ID: NA SEPTEMBER 24, 2012 Prepared by: The Minnesota ...»
Assessment of Lead Smelters in Minnesota:
National Lead and
Northwestern Smelting and Refining
MINNEAPOLIS, HENNEPIN COUNTY, MINNESOTA
ST. PAUL, RAMSEY COUNTY, MINNESOTA
EPA FACILITY ID: NA
SEPTEMBER 24, 2012
The Minnesota Department of Health
Environmental Health Division Under Cooperative Agreement with the Agency for Toxic Substances and Disease Registry U.S. Department of Health and Human Services
FOREWORDThis document summarizes public health concerns related to an industrial facility in Minnesota.
It is based on a formal site evaluation prepared by the Minnesota Department of Health (MDH).
For a formal site evaluation, a number of steps are necessary:
• Evaluating exposure: MDH scientists begin by reviewing available information about environmental conditions at the site. The first task is to find out how much contamination is present, where it is found on the site, and how people might be exposed to it. Usually, MDH does not collect its own environmental sampling data. Rather, MDH relies on information provided by the Minnesota Pollution Control Agency (MPCA), the US Environmental Protection Agency (EPA), and other government agencies, private businesses, and the general public.
• Evaluating health effects: If there is evidence that people are being exposed—or could be exposed—to hazardous substances, MDH scientists will take steps to determine whether that exposure could be harmful to human health. MDH’s report focuses on public health— that is, the health impact on the community as a whole. The report is based on existing scientific information.
• Developing recommendations: In the evaluation report, MDH outlines its conclusions regarding any potential health threat posed by a site and offers recommendations for reducing or eliminating human exposure to pollutants. The role of MDH is primarily advisory. For that reason, the evaluation report will typically recommend actions to be taken by other agencies— including EPA and MPCA. If, however, an immediate health threat exists, MDH will issue a public health advisory to warn people of the danger and will work to resolve the problem.
• Soliciting community input: The evaluation process is interactive. MDH starts by soliciting and evaluating information from various government agencies, the individuals or organizations responsible for the site, and community members living near the site. Any conclusions about the site are shared with the individuals, groups, and organizations that provided the information. Once an evaluation report has been prepared, MDH seeks feedback from the public. If you have questions or comments about this report, we encourage you to contact us.
On the web: http://www.health.state.mn.us/divs/eh/hazardous/index.html ii
TABLE OF CONTENTSFOREWORD
TABLE OF CONTENTS
List of Acronyms
II. Background and Site History
A. Soil lead guidance
B. National Lead in St. Paul
C. Northwestern Smelting and Refining in Minneapolis
D. Site visits
B. Blood Lead Surveillance
C. Exposure to Lead
D. Local public health lead programs
VI. Public Health Action Plan
Appendix B: Map of USA Today soil sampling near former Northwestern Smelting and Refining in Minneapolis Appendix C: MDH information sheet - Lead in Soil
ATSDR – Agency for Toxic Substances and Disease Registry BLIS – blood lead information system CDC – Centers for Disease Control and Prevention EBLL – elevated blood lead level EPA – U.S. Environmental Protection Agency IEUBK – Integrated Exposure Uptake Biokinetic Model for Lead in Children MDA – Minnesota Department of Agriculture MDH – Minnesota Department of Health MPCA – Minnesota Pollution Control Agency PAHs – polycyclic aromatic hydrocarbons ppm – parts per million QA/QC – quality assurance/quality control SRV – soil reference value µg/dL – micrograms per deciliter XRF – X-ray Fluorescence v I. Introduction On April 19, 2012, USA Today published its investigation into former lead smelters across the country and their suspected role in childhood lead poisoning (USA Today, 2012a). USA Today spent 14 months looking for evidence of historic lead smelter locations and ultimately measured lead levels in soil in 13 states, finding elevated levels in all the neighborhoods they sampled. On May 9, 2012, six members of the U.S. Senate sent a letter to EPA Administrator Lisa Jackson requesting immediate action to review these sites to determine priority locations for remediation.
As a result, the Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Health (MDH) have conducted site visits and reviewed data for two former smelter sites in Minnesota highlighted in the USA Today coverage.
II. Background and Site History Lead smelters emit lead and other metal particulates into the air which can be carried downwind and deposited in soil. This deposition is important because lead is relatively persistent and immobile in the environment and may accumulate at the soil surface where people may be exposed. In 2002, after a paper was published in the American Journal of Public Health describing suspected historical lead smelting sites (Eckel et al., 2001) the EPA provided the names of two suspected former lead smelters to the MPCA - Northwestern Smelting and Refining in Minneapolis and National Lead in St. Paul - and requested that the MPCA determine if further investigation of lead contamination was needed. Due to the lack of evidence found at that time regarding potential past releases of lead from the smelter sites, no further action was taken.
Assessing historic point sources for lead in urban areas is severely constrained by the extensive distribution of lead from gasoline, leaded paint, and a range of industrial and commercial products. Lead poisoning prevention programs at MDH, the City of Minneapolis, and St. PaulRamsey County have worked for years to raise awareness of lead hazards and implement environmental and medical case management procedures in response to elevated blood lead results. Both smelters identified by USA Today are within areas already established as urban areas at high risk for lead exposure, based on the age of housing and socio-economic status of the population.
1 A. Soil lead guidance
EPA has developed the Integrated Exposure Uptake Biokinetic (IEUBK) Model for Lead in Children to assess risk from lead. The IEUBK Model is designed to model exposure from lead in air, water, soil, dust, diet, and paint and other sources with pharmacokinetic modeling to predict blood lead levels in children 6 months to 7 years old. The IEUBK Model is used to estimate risks from childhood lead exposure to soil and household dust that might be encountered at contaminated sites. The IEUBK Model predicts the probability that a typical child will have an elevated blood lead level (EBLL) when exposed to specified lead concentrations. EPA used the model to develop a soil lead screening value of 400 ppm, which is based on model inputs of no more than 5% of the population exceeding a blood lead concentration of ten micrograms of lead per deciliter of blood (10 µg/dL). Using the same inputs to model, MPCA chose to round down to 300 ppm for their soil reference value (SRV) to be more protective because it has been known for many years that any amount of lead in children can be harmful. New CDC guidance in 2012 has changed from identifying a blood lead level of concern at 10 µg/dL to identifying a reference level for elevated lead in the population at 5 µg/dL. One of the goals of this new guidance is to catch elevated blood lead in children earlier and to take steps to prevent a child’s future exposure to lead. It is unclear whether EPA will lower soil screening levels in the future in response to CDC’s new guidance.
MDH has established a general lead standard of 100 ppm for bare surface soil in residential areas. This value is used as a criterion to mitigate soil lead when children living at a residence are found with EBLLs. Without identification of EBLLs, remediation of lead in residential soil in Minnesota is typically triggered by exceeding the SRV of 300 ppm.
B. National Lead in St. Paul
USA Today discovered the existence of the National Lead site in St. Paul listed on a historical Sanborn fire insurance map. According to USA Today, National Lead was a manufacturer of lead pipe, babbit, solder, and printer’s metals. The dates of operation were not discovered from an internet search but the St. Louis Park Historical Society notes that National Lead may have begun moving certain functions to St. Louis Park as early as 1933-34, so perhaps operations in St. Paul began a number of years prior to the early 1930s (St. Louis Park Historical Society, 2012). This former smelter site was located in a light industrial area off of Plato Boulevard where the street names have changed over the years (for map see Appendix A). The immediate area contains several former contaminated sites that have been remediated; two are known to have contained high lead levels from battery recycling and scrap metal operations. This area is largely paved and redeveloped. Harriet Island, a nearby park, has been newly landscaped. USA Today sampled the soil in the area and reported 54 lead results at 15 locations in parks and residential areas south of the former smelter and found elevated levels at four locations (see
Vicinity of Livingston Ave. 95 XRF 1 XRF (95) and E. George St.
100 block of E. Baker 48 XRF 1 XRF (48) *XRF, or X-ray Fluorescence, is a method used to measure lead in soil with a portable field instrument. Lab refers to soil samples sent by USA Today to an analytical laboratory at Tulane University to validate findings. Detailed quality assurance/quality control (QA/QC) data were not provided by USA Today upon MPCA request.
Bolded values are above the MPCA’s lead residential soil reference value (SRV) of 300 ppm.
The majority of the samples were analyzed by X-ray Fluorescence (XRF) using a portable field instrument. XRF is a technique using the interaction of X-rays to determine the elemental composition of a material. Sampling by XRF can offer considerable reductions in cost and time 3 compared to standard lab methods, and decisions regarding the need for additional sampling can be made in the field (US EPA, 2004). USA Today posted a video of their sampling, which shows an XRF instrument placed directly on the soil surface to take measurements. This method of sampling in place using XRF leads to concerns regarding precision and accuracy. USA Today intended to validate sample results through laboratory analysis; however, the data quality of the laboratory results is uncertain due to their failure to use standard laboratory methods. Despite the lack of confidence in the data, it is not unusual for lead to be found in these urban locations.
C. Northwestern Smelting and Refining in Minneapolis
Northwestern Smelting and Refining was formerly located at 2523 Hiawatha Avenue in Minneapolis (for map see Appendix B). This former smelter, which is known to have operated in the 1940s, was located in what is now a light commercial/industrial area that has been largely paved and redeveloped. USA Today conducted soil sampling and reported 75 lead results from 20 locations (see Table 2). Elevated lead was found in six locations in adjacent neighborhood blocks. USA Today reported “dangerous” lead levels in the bare dirt under a tricycle in Minneapolis in one of their videos (USA Today, 2012b).
Site visits were conducted by MDH and MPCA staff on June 7th, 2012. The visits included the approximate location of the former smelters as well as the residential areas sampled by USA Today. Representatives from St. Paul-Ramsey County Department of Public Health participated at the St. Paul location and shared their expertise on childhood lead poisoning prevention. The residential area near the St. Paul site is on top of the bluff south of the former smelter. In Minneapolis, the site visit included residential neighborhoods both to the east and to the west of the former smelter. A daycare was located on the block that USA Today reported a lead level of 704 ppm. As a result, MDH referred the daycare to the City of Minneapolis for a lead inspector visit. As a result, a small area of bare soil was found during the June inspection and the soil was sampled. The concentration was reported as 136 ppm and the inspector provided advice to cover the bare soil as a precaution.
III. Discussion Lead, a naturally occurring metal, can be found in concentrations of approximately 15-20 ppm naturally in soil (ATSDR, 2007). It continues to be used in the production of lead batteries, mainly for use in automobiles. Lead is a very common soil contaminant due to its previous use in gasoline and paints, as well as for a variety of industrial uses. Lead-arsenic compounds were also once used as pesticides. Lead does not degrade and is not mobile in soil. A major contributor of lead in urban areas is from lead-based paints that have chipped off the exteriors of older homes and buildings. Soil lead attributable to paint is most concentrated near the foundations of houses. Most homes in St. Paul and Minneapolis are old enough to once have had substantial concentrations of lead in exterior and interior paint. The 2000 Census documented that 89% of the homes in Minneapolis and St. Paul were built before 1978, which is the year lead was banned in residential paint. The City of Minneapolis reports that levels of 350 ppm in soil collected near house foundations are typical throughout Minneapolis. Elevated lead is also found in residential areas from past emissions of leaded gasoline, especially near busy neighborhood streets.