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Pesticide Monitoring Subnetwork of the
CWS Network - Since 1993, the Illinois
EPA has operated a Pesticide Monitoring
Subnetwork of the CWS Network. Initially,
Illinois EPA tested all wells in the CWS
Network for triazine and alachlor using
immunoassay-screening methods. However,
in the 1998 monitoring cycle Illinois EPA
discontinued the use of immunoassay and
randomly selected 50 percent of the network wells to be analyzed for synthetic organic chemicals
(SOCs) using standard laboratory test methods. In the year 2000 monitoring cycle, the
remainder of the wells in the network were analyzed for SOCs. The Illinois EPA anticipates that
this rotation will be maintained in the future.
Data from the Pesticide Monitoring Subnetwork is verified and stored in SAFE by the Illinois
EPA via LIMS.
Rotating Monitoring Network - The purpose of this monitoring network is to maximize
resources and increase groundwater quality monitoring coverage at CWS wells. During the 1997
monitoring cycle, the Illinois EPA initiated a rotating monitoring network program. As a result
of funding limitations, the Illinois EPA was forced to evaluate the CWS Network monitoring
frequency. The Illinois EPA determined that the primary purposes of the CWS Network referred
to above, could be realized by reducing the monitoring frequency of the network to a biennial
basis.
The Illinois EPA is currently able to concentrate
on specialized monitoring at high priority areas
during alternate years. In 1997, monitoring was
focused on concerns related to highly susceptible
CWS wells. These wells were prioritized as a
result of the detections of organic contaminants in
treated water samples obtained during routine
monitoring required by the Safe Drinking Water
Act. During the 1999 monitoring cycle, attention
focused on “new” CWS wells with little
monitoring history. During the 2001 monitoring
cycle the Illinois EPA, with the assistance of
Illinois Department of Nuclear Safety (IDNS)
conducted a radon-monitoring program.
Data from the Rotating Monitoring Subnetwork is verified and stored in SAFE by the Illinois
EPA via LIMS.
Special Intensive Monitoring Program at Community Water Supply Wells - As a result of
monitoring conducted under the “new” CWS wells sampling program the Illinois EPA began
providing technical assistance to the community of East Alton. To date, this has included
In 2001 the Illinois EPA and the USGS initiated a
project to sample for pesticide metabolites including:
Deethylatrazine; Deisopropylatrazine; Cyanzine-amide;
Acetochlor Ethanesulfunic acid (ESA);
Acetochlor Oxanilic Acid (OXA); Alachlor ESA;
Alachlor OXA; Dimethenamid ESA; Dimethenamid
OXA; Flufenacet ESA; Flufenacet OXA;
Metolachlor ESA; and Metolachlor OXA.
Radon Monitoring Subnetwork – The purpose of
this monitoring network is to attempt to determine
the statewide occurrence of radon in CWS wells. To
accomplish this task the Groundwater Section of
Illinois EPA is utilizing the CWS Network as a
statistical base for the program. The CWS Network
utilizes 17, three week sample periods. Within these
sample periods, the Groundwater Section randomly
selected ten sampling stations. Following this
selection, seven primary stations were selected. The
remaining three stations were held as alternate
stations, which could be sampled if one of the
primary stations could not be sampled.
