vi, 29 pages : color illustrations, color maps ; 28 cm.
General Note:
"National Water-Quality Assessment Program"--Cover. Shipping list no.: 2003-0208-P.
Additional Physical Form:
Also available via Internet at the USGS web site. Address as of 03/17/04: http://water.usgs.gov/pubs/wri/wri034006/PDF/wrir0 34006.pdf; current access available via PURL.