PUBLIC HEALTH ASSESSMENT

NEWTON COUNTY WELLS (a/k/a SILVER CREEK TCE)

JOPLIN, JASPER COUNTY, MISSOURI

**Exposure Calculations**

**Ingestion Exposure Calculations**

IDw = __C x IR x EF__

BW

where:

IDw = ingestion exposure dose (mg/Kg/day)

C = contaminant concentration (mg/L)

IR = ingestion rate

EF = exposure factor

BW = body weight

Adult:

IDw = __.327 mg/L x 2 L/day x 1__

Idw = 0.0093 mg/Kg/day

This calculation assumes that an adult weighs 70 Kg and drinks 2 L of tap water per day.

Child:

IDw = __.327 mg/L x 1 L x 1__

IDw = .0327 mg/Kg/day

This calculation assumes a child weighs 10 Kg and drinks 1 L of tap water per day.

**Inhalation exposure for TCE in drinking water**

In order to estimate the inhalation exposure residents of Saginaw and Silver Creek experienced, we need to make some assumptions. These are: a person breathes in approximately 15 cubic meters of air per day; that they live in a 2000 square foot, three bedroom home; that there is 100% TCE volatilization from water; and that water usage in a home is approximately 120 gallons/bedroom.

The MRL for acute exposure to TCE in air is 2 parts per million. (7)

1 part per million is equal to 5.4 mg/cubic meter

Therefore, the MRL is equal to 10.8 mg/cubic meter

The inhalation exposure for Silver Creek and Saginaw residents is approximately ten times lower than the acute Minimal Risk Level.

**Cancer Calculations**