To
obtain an accurate sample using a bailer, just follow these basic
instructions:
1)
Gently lower the bailer down the groundwater well column. Do not let the
bailer crash into the water table. This will cause agitation and
turbidity through surging and the sudden impact of the sampling device.
2) As
the bailer approaches the water level within the well, be sure to ease
the bailer into the water table for the first 3-6 inches of the bailer
length. The recommended rate of descent for this step is five to 10
seconds.
3)
Once the bailer has been gently lowered into the water table, allow the
bailer to descend on its own until it fills. Do not allow the bailer to
descend to the very bottom of the well. If the bailer comes in contact
with the bottom, it could disturb the sediment that may be settled at
the bottom of the well. This will also cause turbidity within the well
and your sample.
4)
Once the bailer fills, retrieve the bailer from the well slowly, in a
steady, smooth motion. It is neither necessary nor recommended to jerk
or jig the bailer line.
By
simply following these basic steps, you will retrieve accurate
groundwater samples in a cost-effective and timely manner. This extra
care during groundwater sampling when using a bailer adds only one to
two minutes of additional time to complete the task. By utilizing these
methods, sampling with bailers will significantly reduce agitation and
turbidity and provide you with a simple, accurate and cost-effective
means for obtaining groundwater samples.