Pesticides and their Degradation. Products in Surface Water and Ground. Water of the Mid-Atlantic Region. Jeffrey M Fisc
Pesticides and their Degradation Products in Surface Water and Ground Water of the Mid-Atlantic Region
Jeffrey M Fischer US Geological Survey Trenton NJ
Why study Pesticide Degradation Products? • When measured, degradation products are often detected more frequently than parent compounds. • Concentrations of pesticide degradates often exceed concentrations of parent compounds.
Sources of Data • Primarily National Water Quality Assessment Program (NAWQA) • State Programs • Cooperative studies
What analyze for? • Widely used pesticides and their degradation products. • 2-3 lab schedules, >150 compounds D elaw are R iver B asin Agricultural Pesticide U se, 1992 (usage greater than 25,000 pounds per year show n) 600,000
500,000
300,000
200,000
100,000
ID
E
EB
M O
M Y
AN M
YL _
BR
E N
ET H O
AZ I
TE O LI Y R
C
SI M
N R U N
L
ET H
H C
O
S R PY
R LO
C
LI
IF O
4_ D 2_
E YA
N
C
O
AZ I
N
ZE B
IL AN
AL O
N M
M
M
C
H
LO
G
R
O
TH
LY PH
O
S
TH
A
AT E
LI N
N TA IM E D N
H
AP C PE
LO R
IL O AL AC
E N AZ I AT R
H C
ET O LA
SU
LF
LO
U
R
R
0
M
Pounds Applied
400,000
Frequently Detected Pesticides Primarily discussing degradation products of: Detection frequencies vary seasonally Detections greater in streams than wells
• Triazine Herbicides • Acetalinide Herbicides • Few Other Pesticides
Herbicide Degradates in Streams Metolachlor degradates in the Schuylkill River
Not detected
Piedmont Valley & Ridge Glacial Fill
AZ AT R
INE DE E
L TH Y
AZ ATR
LD TH Y
E IS
O
P RO
PYL
INE
Long Island
50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0%
ME
AZ ATR
Piedmont Valley & Ridge Glacial Fill
Not detected
Percent Detection
DE E
INE
TO
H LAC
LO
R
M
O ET
L AC
HL
ES OR
A ME
TO
LA
L CH
OR
OA
Not detected
P e r c e n t D e te c tio n
Long Island
70% 60% 50% 40% 30% 20% 10% 0%
Geologic Differences • Time since applied • Age of water • Thickness of Unsaturated Zone? • Permeability? • Soil Properties?
Pesticide Concentrations in Streams and Domestic Wells • Degradate concentrations typically are equal to or greater than parents • Degradates have no drinking water standards, but sometimes approach MCL for parents. Concentration (ug/L)
Toxicity of Degradates
Other Recent Pesticide Sampling Frequently Detected Pesticides in Ground Water
• In surface water: Carbaryl,
Metalaxyl,
Fipronil sulfone
• Sampled Raritan and Delaware Rivers • 32 of 83 pesticides detected, including • 9 degradates
Metsulfuron, Im azethapyr, Acifluorfen, OIET
3,5-Dichloroaniline,
3-Ketocarbofuran,
• In ground water: Metolachlor,
Fenuron,
• Sampled 34 monitoring wells in Coastal Plain • 135 of 137 pesticides detected, including • 34 degradates Dieldrin,
Im idacloprid,
Prom eton,
Atrazine,
Caffeine, CIAT
CEAT
Sim azine,
0%
10%
20%
30%
40%
Percent Detection
50%
60%
Other Pesticide Degradates Fipronil
Desulfinyl fipronil Desulfinylfipronil amide Fipronil sulfide
Streams wells
Fipronil sulfone 0%
10%
20%
30%
40%
50%
60%
• Fipronil Maximum Parent concentrations • SW=0.020 ug/L; GW=0.100 ug/L
• Maximum Degradate concentrations • SW=0.013 ug/L; GW=0.194 ug/L
Summary • Pesticide degradation products are often detected more frequently than parent compounds. • Concentrations of pesticide degradates often exceed concentrations of parent compounds, especially in ground water. • Formation of degradation products is controlled by geologic and hydrologic conditions as well as chemical properties. • Degradation products have no standards for protection of humans or wildlife.
