Laserfiche WebLink
Z rT <br /> CLEARWATER <br /> G R O U P 1 N C <br /> E n iru rr men t.!5orveus <br /> 4 3 Dissolved Oxygen in Groundwater <br /> The dissolved oxygen (DO) content of purge water from each well was measured in <br /> the field on June 16, 1997 DO content ranged from 0 25 milligrams per liter (mg/1) <br /> in groundwater from MW-2 to 3 40 mg/1 in groundwater from MW-6 (Table 2 and <br /> Figure 4) <br /> In general, DO concentrations above 2 mg/l indicate aerobic conditions, although <br /> some aerobic bioremediation may occur at DO concentrations down to 1 mg/1 The <br /> DO concentration in groundwater from well MW-2 (0 25 mg/1) appears to be <br /> depleted relative to DO concentrations in other wells MW-2 is proximal to the <br /> source area, and the groundwater contains elevated contaminant concentrations <br /> The depleted DO concentration in groundwater from MW-2 suggests that some <br /> natural bioremediation of petroleum hydrocarbons may be occurring in the center <br /> of the dissolved hydrocarbon plume However, historical analytical data indicate <br /> that, while petroleum hydrocarbon concentrations in groundwater from MW-2 <br /> have been variable, there is no apparent trend suggesting that the concentrations are <br /> decreasing over time The concentrations of dissolved hydrocarbons in MW-5, <br /> however, do appear to be decreasing over time, suggesting that the outer portion of <br /> the plume may be undergoing aerobic bioremediation Dissolved oxygen <br /> ' concentrations in groundwater from MW-5 were 180 mg/i and 0 80 mg/1 during <br /> sampling events in March and June 1997, respectively <br /> D-101 1Q97 <br /> July 23, 1997 <br />