Table 3.

Pesticides and degradation products monitored in reservoir water samples (n = 206).

Herbicide	Percent of samples with detection	Detection limit (ng/L)	No. of samples with detection	Maximum concentration (ng/L)
2,4-D	100	0.47	206	1,850
MCPA	99	0.58	205	374
Clopyralid	99	0.59	205	1,050
Dicamba	86	0.73	179	1,040
Diclorprop	82	0.42	171	113
Mecoprop	77	0.50	160	83.1
Bromoxynil	54	0.99	112	384
Ethametsulfuron	35	0.01	73	80.4
Atrazine	27	5.76	48	52.7
Tribenuron	20	0.01	42	30.1
Desethylatrazine	21	26.80	37	(20.8)a
Picloram	13	0.66	27	457
Imazamethabenz A	13	0.14	27	194
Desethylsimazine	12	148.00	22	(25.3)
2,4,5-T	11	0.39	23	4.18
Sulfosulfuron	10	1.0	21	36.1
Fenoprop	9	0.40	19	5.8
Imazamethabenz B	7	0.09	15	93.5
2,3,6-TBA	6	1.10	12	2.43
Imazethapyr	6	1.20	12	11.0
Thifensulfuron	3	1.0	7	12.0
Butylate	3	55.40	5	(3.12)
Metsulfuron	2	1.0	5	2.1
MCPB	2	0.63	5	12.8
Diclofop	2	42.30	4	(4.4)
Benzoylprop	1	26.20	2	(1.3)
Simazine	1	16.40	2	(13.8)
Triallate	1	4.14	2	(3.9)
Trifluralin	1	5.15	2	(1.0)
Metribuzin	< 1	20.7	1	185
Chlorpyrifos	3b	14.80	5	20.1
Dimethoate	1b	25.10	1	(5.98)

^aValues in parentheses are estimates of concentration below the reporting limit.

^bn = 30.