USGS Scientific Investigations Report 2011-5082 - Occurrence and Distribution of Pesticides in Surface Waters of the Hood River Basin, Oregon, 1999

Table 5. Counts of samples and detections for pesticides analyzed from 1999 to 2009, sites where pesticides were detected, and concentration, date, and site of the maximum detected concentration for the entire period of record and for 2009.

[Sample size includes all (unscreened) samples. µg/L, micrograms per liter; –, not detected in 2009]

Pesticide type	Class	Pesticide	Number of samples	Number of detections	Sites where detected	Maximum concentration 1999–2009			Maximum concentration 2009
Pesticide type	Class	Pesticide	Number of samples	Number of detections	Sites where detected	Measurement (µg/L)	Date	Site	Measurement (µg/L)	Date	Site
Herbicide	Triazine	Atrazine	920	2	Lenz	0.032	05-31-02	Lenz	–	–	–
		Simazine	933	157	Baldwin; Evans; Hood, East Fork; Hood, mouth; Hood, Indian; Lenz; Neal, middle; Neal, mouth; Neal, upper, below diversion; Rogers	1.9	06-13-03	Lenz	0.299	09-16-09	Lenz
Insecticide	Organophosphate	Azinphosmethyl	939	76	Evans; Hood, Middle Fork; Hood, mouth; Lenz; Neal, middle; Neal, mouth; Neal, upper, above diversion	0.375	09-12-03	Lenz	0.028	09-16-09	Lenz
		Chlorpyrifos	944	66	Evans; Hood, East Fork; Hood, Middle Fork; Hood, mouth; Indian; Lenz; Neal, middle; Neal, mouth; Neal, upper, above diversion; Rogers	0.482	03-22-99	Neal,mouth	–	–	–
		Diazinon	945	4	Baldwin; Neal, mouth	0.19	06-20-00	Neal,mouth	–	–	–
		Malathion	946	7	Lenz; Neal, mouth	0.098	06-16-04	Lenz	–	–	–
		Phosmet	895	14	Evans; Lenz; Neal, middle; Neal, mouth; Neal, upper, above diversion	0.278	06-13-02	Lenz	–	–	–

Occurrence and Distribution of Pesticides in Surface Waters of the Hood River Basin, Oregon, 1999–2009