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to indexEach well monitoring event will require the following supplies and equipment:
An electric sounder and an engineer's tape
(in tenths of feet) for measuring depth to water below the land
surface.
Forms for recording field data
Checklist form
Maps of well locations
500 milliliter polyethylene bottles (one per well) with screw on
lids with water-proof (high rag content) label or texture
suitable for inscribing sample data.
The sample bottle should contain approximately 2 ml of sulfuric
acid to preserve the sample. The proper treated containers would
be obtained from the laboratory doing the analyses.
A large cooler with frozen blue ice in which to transport the
samples.
"Chain-of-custody" forms (in triplicate) on which to
document the handling of the samples and their transfer to the
laboratory.
Nitrate Test Kit, for measuring nitrate concentrations in the
well water in the field.
An indelible, non-water soluble marking pen to mark the sample
label.
Sample labels.
Large/ zip-lock bags (large enough to hold
at least one of the bottles.
Large bucket (5-10 gallons ) with handle.
The following well sampling procedures are simple to allow the community to use its own resources, with appropriate training and supervision, and are similar to and enhanced from the procedures employed by UC Riverside. The hydrogeolocist contracted to the ADWC would oversee the monitoring. He would initially train the monitoring personnel and periodically review their procedures in the field. The data from this program will be compatible with the UC Riverside data, because the same wells can be incorporated into this study, and the sampling techniques will be equal or enhanced.
1. Sampler should fill out the chain-of-custody form with the date, well identifier, and other required observations.
2. The designated water tap or faucet would be turned on until the pump is started.
3. A small beaker will be filled with well water for the field nitrate measurements. The sampler will measure nitrate concentrations every five minutes until the readings have stabilized (e.g.', three consecutive readings are essentially the same).
4. Stabilization of nitrate concentrations should occur within 20 minutes of when pumping commences. The time required should be noted on the "remarks" section of the chain-of-custody form for that sample.
5. Without allowing the flowing water to contact any other surface, the sample bottle mouth will be inserted into the flow of water and filled to near the top, but not allowed to overflow the container. A large enough sample will be collected to allow re-analysis, if requested.
6. The sample container will be sealed, and then shaken to thoroughly mix the nitric acid with the water.
7. The water sample is then logged! labeled, and chilled. Clean ice chests and ice or blue ice are used to keep the samples cold until delivered to the State-certified analytical
laboratory,
8. Samples will be delivered directly to the laboratory by the close of business on the same day of sampling.
9. Samples will be accompanied by a chain-of-custody form which documents the time, date, and responsible person during each step of the transportation process.
The field log book will also be filled out, documenting date, purge time, field parameter measurements and time of measurements, etc.
Samples will be analyzed by a State certified laboratory for nitrate using a standard methodology such as U.S. EPA's "Methods of Chemical Analysis for Waters and Waste" (EPA 600/4-79-020) or Standard Methods. The results of the nitrate field measurements for the initial sampling round will be compared to the laboratory results. If an acceptable comparison is obtained (within about 5% when concentrations exceed 35 mg/1), then the field kit will be used in the future to replace most of the laboratory analyses. At a minimum, ten percent of the samples will be submitted for laboratory analyses for confirmation of the field measurements for future sampling rounds.
The laboratory chemical analyses will be conducted by a California-certified testing laboratory, with Level 3 quality control. Level 3 is the minimum level acceptable for use of data in human health and ecological risk assessments. Laboratory analysis will be performed using control procedures described in the following paragraphs.
Laboratory Quality Control Procedures
Laboratory quality control samples will include method blanks, laboratory duplicates, matrix spikes and matrix spike duplicates. These are described below. The method (reagent) blank is used to monitor laboratory contamination. This is usually in a sample of laboratory reagent grade water or soil matrix treated with all the reagents and in the same manner as the sample-(i.e., digested, extracted, distilled). One method blank is prepared and analyzed every day for each batch of up to 20 samples. The method blank must contain less than the method's quantitative limit for the compounds of concern, unless the coin-pound is a common laboratory contaminant such as methylene chloride and/or acetone. If this criterion is not met, than all sample processing will be halted until corrective measures are taken and documented. Duplicates prepared in the laboratory account for analytical variability only. Although this monitors analytical precision, the result can be affected by sample heterogeneity. Laboratory duplicates are prepared by splitting a field sample in the laboratory. Bach of the two aliquots for laboratory duplicates are analyzed following the same procedures. The two containers should be taped or strapped together, if possible' to ensure that they are different from that of any other sample of similar matrix.
Sufficient samples must be collected so that the laboratory can prepare and analyze a laboratory duplicate at a frequency on one out of every batch or one in 20 field samples, whichever is more frequent. Laboratory matrix spikes are an interval QC check supplied by the laboratory. Matrix bias and analytical accuracy will be assessed by preparing and analyzing matrix spikes in accordance with EPA 1991b or appropriate methodologies. Matrix spikes will be prepared in the laboratory by fortifying a sample aliquot with a known concentration of the compound of interest. This fortified aliquot is then analyzed along with an unfortified aliquot and the percent recovery of the analyte within the representative sample matrix is calculated. Matrix spikes will be prepared in the laboratory and analyzed at a frequency of one out of every batch or one in 20 field samples, whichever is more frequent. Enough sample should be collected in one container so that the matrix spike can be prepared. Matrix spike duplicate samples are analyzed to ascertain the repeatability of matrix spike results. In this way, the precision of matrix spike analysis can be assessed and evaluated in regard to matrix effects and analytical technique.
Analytical data generated by the laboratory will be reviewed by appropriate laboratory personnel as defined in the laboratory's Quality Assurance Plan to verify the following:
Appropriate units are assigned to concentration values.
Equations used to calculate concentrations are correct.
Quality control sample results are appropriately summarized and within established control ranges.