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LeMasters, Gary S.; Doyle, Douglas J. / Grade A dairy farm well water quality survey
[DNR-058] (1989)

Methods,   pp. 3-10 PDF (430.5 KB)


Page 6

Sample Collection
The water samples were collected by the Food Division inspectors over the
period August, 1988 to February, 1989. The samples for pesticide analysis
were collected in washed and capped one-liter amber glass bottles with Teflon-
lined caps. The NO3-N samples were collected in 125-milliliter (ml)
polypropylene bottles. All samples were collected from the cold water tap at
the two compartment wash sink. The tap was allowed to run for at least five
minutes before a sample was collected. No attempt was made to collect the
sample before any water treatment device that may have been present. All
samples were placed in an insulated shipping container, refigerated with
prefrozen ice packs and shipped to the WDATCP General Laboratory via courier
service. All samples were received by the laboratory within 48 hours of
sampling. About 25 farms were sampled each week. The three Food Division
Region offices scheduled sample collection with their inspectors, with sampling
rotating between the three regions on a weekly basis.
Sample Analysis
Pesticide concentrations were determined using the Neutral Extractable
Method of the State Lab of Hygiene Organics Section, Method 1200 (Wis. Lab.
of Hygiene, 1988). The analytes that can be detected using this method are
shown in Table 3. The WDATCP General Laboratory analyzed about 150
samples for N03-N and the State Laboratory of Hygiene analyzed the remaining
samples. Both laboratories used the Cadmium Reduction Method 418C (USEPA,
1979) with a reporting level of 0.5 mg/l.
Notification
Each participant was notified of the sample results by letter. If an ES for a
pesticide was exceeded and was confirmed by followup sampling the well owner
was advised to seek an alternative source of drinking water. If the
concentration of N03-N exceeded the ES of 10 mg/l the well owner was advised
that the water should not be consumed by infants under six months of age.
The pamphlet Pesticides in Drinking Water (WDNR, 1985) was sent to each
participant where pesticides were detected at any concentration. The pamphlet
Nitrate in Drinking Water (WDNR, 1986) was sent to each participant where
N03-N was detected above the ES.
Followup to Detections
Each well containing a pesticide above an ES was resampled and a milk sample
was collected also. The water sample was split between the WDATCP General
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