April 17, 2002

New Dioxane Finds in City

SRSW received well logs for the new monitoring wells (MW-76s,MW-76i,MW-76d, located at Jackson & Worden, east of the fire station.

The surface elevation there is about 927'.

The well logs show the following dioxane sample results at various depths(03/25/02):

59 ppb @ ~ 80 ft

72 ppb @ ~ 100 ft

53 ppb @ ~ 120 ft

33 ppb @ ~ 140 ft

35 ppb @ ~ 170 ft

<diamicton/silt layer at 196-217 ft>

15 ppb @ ~ 190 ft

16 ppb @ ~ 200 ft

10 ppb @ ~ 240 ft

12 ppb @ ~ 260 ft

<shale encountered at 273 ft> (no dioxane sample)

The highest concentrations are at an elevation 807-847, well above the E unit. How it got there without being detected earlier is a new mystery.

It's also bad news that the E unit shows 12-16 ppb over some 70 foot thickness there.

MW-72 near where I-94 crosses Jackson Road is now up to 2370 ppb.

The city supply well at Montgomery remains closed with latest readings still at 2 ppb.