Features:
Concentrations and detection frequencies of pesticides, nutrients, VOC's
and trace elements in NAWQA study units begun in 1997 can be selected and
plotted above.
Summaries of chemical concentrations and detection
frequencies from individual study units are compared to findings from 1991
to 2001 and to water-quality benchmarks for human health, aquatic life,
fish-eating wildlife, or prevention of nuisance plant growth. These
graphical summaries provide a comparison of chemical concentrations and
detection frequencies between (1) surface- and ground-water resources, (2)
agricultural, urban, and mixed land uses, and (3) shallow ground water and
aquifers commonly used as a source of drinking water.
Note to users:
The analytical detection limit varies among the monitored chemicals, thus
frequencies of detections are not comparable among chemicals.
When comparing data, the detection frequency should be considered along
with the concentration.
Quality control data for the analytes listed above had relatively frequent
low-level contamination of samples during sample processing. Results for
these analytes cannot, therefore, be presented using the generalized
methods that were applied to other analytes. Analysis of results for
analytes potentially affected by contamination requires special
statistical treatment beyond the scope to this web page. For more
information about these analytes and how to interpret data on their
occurrence and concentration, please contact the appropriate NAWQA Study
Unit.
Trace elments in ground water: aluminum, barium, boron, cadmium,
chromium, cobalt, copper, lithium, nickel, strontium, zinc
SVOC's in bed sediment: phenol, bis(2-ethylhexyl)phthalate,
butylbenzylphthalate, di-n-butylphthalate, idethylphthlate
Insecticides in water: p,p'-DDE