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

Table 6. Percentage of samples exceeding U.S. Environmental Protection Agency or Oregon freshwater aquatic life standards, 1999–2009.

[Sample size includes screened samples, not total samples. All concentrations reported in micrograms per liter; Abbreviations: USEPA, U.S. Environmental Protection Agency; CMC, criteria maximum concentration; CCC, criterion continuous concentration; %, percent; —, no water-quality standard; <, less than]

Pesticide		USEPA Office of Pesticide Programs   Aquatic Life Benchmarks				USEPA Water  Quality Criteria			Oregon Water   Quality Criteria		Percentage exceeding lowest standard (%)
		Fish		Invertebrates		USEPA Water  Quality Criteria			Oregon Water   Quality Criteria
		Acute	Chronic	Acute	Chronic	CMC (Acute)	CCC (Chronic)		Acute	Chronic
Atrazine		2,650	65	360	60	–	–		–	–	0
Azinphos-methyl¹		0.18	0.055	0.08	0.036	–	–		–	0.01	7
Sites where detected	Evans								2
	Lenz								26
	Neal, middle								3
	Neal, mouth								19
	Neal, upper, above diversion								0.9
Chlorpyrifos		0.9	0.57		0.05	0.04		0.083	0.041		0.083	0.041	3
Sites where detected	Evans										2
	Hood, mouth										1
	Indian										100
	Lenz										6
	Neal, middle										2
	Neal, mouth										11
Diazinon		45	0.55		0.105	0.17		0.17	0.17		–	–	0.3
Sites where detected	Baldwin										4
	Neal, mouth										1
Malathion		0.295	0.014		0.005	0.000026		–	0.1		–	0.1	0.4
Sites where detected	Lenz										0.9
	Neal, mouth										2
Phosmet		35	3.2		1	0.8		–	–		–	–	0
Simazine		3,200	960		500	2,000		–	–		–	–	0

¹Listed in Oregon Department of Environmental Quality (2004), Table 20 as Guthion (product name)

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