Vapor Study Informational Meeting

General Mills/Henkel Corp. Superfund SiteVan Cleve Recreation Center

November 12, 2013

Minnesota Department of HealthMinnesota Pollution Control Agency

What we will cover The Issue Health Information Your Involvement The Solution

Our MissionsMDH To protect, maintain and improve the

health of all Minnesotans

MPCA To protect and improve the

environment and enhance human health.

MPCA vs. MDH Roles

Outside: MPCA or EPA Inside: MDH

General Mills/Henkel Corp. Superfund Site

Disposal “Absorption Pit” Former General Mills research facility 1930-1977 Used and disposed of chemicals on the site from 1947-1962 Main contaminant of concern: Trichloroethylene (TCE)

Groundwater Contamination 1981 contamination confirmed Groundwater ‘plume’ about ½ mile off the property to the SW 1985 groundwater pump and treat system installed 2010 groundwater system turned off, increased monitoring

Is There Vapor Intrusion?

What are Volatile Organic Compounds (VOCs)? Chemical solvents used for cleaning and degreasing

frequently found at waste sites Commonly found in consumer products Easily evaporate from products, or soil and water if spilled

or disposed The major VOC of concern at the General Mills site is

trichloroethylene (TCE)

Why is Vapor Intrusion a Possible Public Health Concern? Studies show people spend about 85 - 90% of their time

indoors (even children) There has been a growing interest in indoor air quality The science of indoor air assessment has grown

tremendously in recent years Radon gas awareness:

Effective January 1, 2014, the Minnesota Radon Awareness Act requires additional disclosure and education be provided to potential home buyers during residential real estate transactions in Minnesota. Before signing a purchase agreement to sell or transfer residential real property, the seller shall disclose in writing to the buyer any knowledge the seller has of radon concentrations in the dwelling.

Inhalation Exposure

Difficult to estimate how much is absorbed

Behavior driven Large differences between

individuals Thus, exposures vary

between people

MDH health based criteria protect vulnerable people

Inhalation health based value for Trichloroethylene U.S. EPA and MDH recently completed a TCE

toxicological review An increased risk of heart defects in newborns and immune

effects were found in recent studies We now calculate short term values based on exposures

that occur in utero, infancy, or early childhood, to ensure values protect everyone’s health

TCE health based value is 2 mg/m3 in air

Groundwater → Soil Vapor → Sub-slab Vapor → Indoor Air

Exposure Pathway

Sub-Slab Vapor Sampling

Goal is to find out is there vapor intrusion Sample soil vapor directly below basement floor Results generated quickly Used for decision-making Indoor air has contaminants from sources inside the house

What if TCE Vapor is Found?

Screening values are very protective – even if exceeded the risk is still very low

Basement floor and walls provide protection Level of protection is 10 times the health based value Safe indoor air TCE less than 2 ug/m3

Sub-slab sample TCE less than 20 ug/m3 No risk from vapor

intrusion Mitigation systems are effective and easy to install

What’s next? Sign an access agreement Sampling begins the week of November 18 Mitigation if needed

Mitigation also prevents infiltration of naturally occurring radon gas

QuestionsMinnesota Department of Health Rita Messing, Ph.D.: rita.messing@state.mn.us Emily Hansen, M.S.: emily.hansen@state.mn.us Site Assessment and Consultation Unit: (651) 201-4897

Minnesota Pollution Control Agency Hans Neve

hans.neve@state.mn.us, (651) 757-2608 Fred Campbell fred.campbell@state.mn.us, (651) 757-2260

Thank You

Indoor Air Sampling

Typically use stainless steel (Summa) canisters that are under a vacuum

Long-term (up to 24 hour) sample time Do’s and don’ts: no smoking, don’t use fireplace or

candles, do keep windows closed Home chemicals need to be removed prior to testing

to minimize interferences: e.g. TCE in cleaners

Need very low detection limits

U.S. EPA TCE Review

Non-cancer effects are driving the risk

19

72 studies

3 critical studies and

2 supporting

studies20 studies

Immunosuppression, autoimmune disease, hypersensitivity; decrease in thymus weight; heart defects in the developing fetus

Neurologic, kidney, liver, immune, reproductive, and developmental effects

kidney effects