Urban Storm Water Runoff Monitoring for Pesticides and Nitrate in Helena and Billings

Rick Mulder

Montana Department of Agriculture

Groundwater Protection Program

Sample Collection

Helena

• 4 sampling locations• 9 rainfall events• 36 total samples

– June 6, 23; July 14; Aug 5, 2011– May 26, 27; July 16, 17; August 27,

2012

• Samples collected from ditches or discharge pipes

Billings

• 3-4 sampling locations• 2 rainfall events• 7 total samples

– June 16; Aug 29, 2011

• 6 samples collected from receiving waters; 1 sample collected from discharge pipe

All samples taken to the MDA Analytical Lab and tested for 148 pesticide compounds and nitrate

Helena Sampling Locations

Billings Sampling Locations

Pesticide Results

Helena

• 31 different pesticide compounds detected

• Average of 13 pesticides per sample

• One sample with 25 different pesticide compounds

Billings

• 26 different pesticide compounds detected

• Average of 15 pesticides per sample

• One sample with 24 different pesticide compounds

Pesticide Results

2,4-D (Weed B Gon, Trimec)AMPA (Roundup, Ground Clear)Atrazine (Aatrex, Atrazine 90DF)Azoxystrobin (Heritage, Renown)Bromacil (Krovar, Hyvar)Carbaryl (Sevin)Chlorathalinil (Heritage, Manicure)Chlorsulfuron (Corsair, Cimarron)Chlopyralid (Confront, Momentum)Deethyl atrazine (Aatrex, Atrzine 90DF)Diazanon (Spectracide)Dichloprop (Triamine)Diuron (Karmex)Fipronil (Frontline)Glyphosate (Roundup, Ground Clear)Imazapic (Panoramic, Plateau)Imazapyr (Ground Clear, Arsenal)

Imidacloprid (Admire, Pravado)MalthionMCPA (Weed-n-feed, Weed B Gon)MCPP (Trimec)Picloram (Tordon, Grazon)Prometon (Pramitol, Total Kill) Propaconazole (Banner, Tilt)Simazine (Pramitol, Pricep)Sulfomuterun (Oust)Tebuconazole (Elite, Folicur)Tebuthiruon (Spike, Reclaim)Triclopyr (Garlon, Remedy)

Pesticide Results

• Phenoxy herbicides2,4-D, MCPA, MCPP

• Soil SterilantsDiuron, glyphosate, prometon, tebuthiuron,

triclopyr

Pesticide Results

Surface WaterStorm Water

10

8

6

4

2

0

Conce

ntr

ation (

ppb)

1.1

0.0115

Boxplot of 2,4-D Concentrations in Storm Water and Surface Water

n = 43

n = 104

Drinking Water Standards

Site Pesticide DateConcentration

(ppb)

Drinking Water Standard

(ppb)BILSS-2 MCPP 6/16/2011 3.9 7HLNSS-4 MCPP 6/23/2011 3.6 7HLNSS-4 MCPP 8/5/2011 4.6 7HLNSS-1 MCPA 8/5/2011 2.2 4HLNSS-4 Diazanon 5/27/2011 0.3 0.6HLNSS-4 MCPA 7/16/201 33 4

Aquatic Life Benchmarks

Site Pesticide DateConcentration

(ppb)

ALB Acute Vascular Plants

(ppb)

ALB Acute Invertabrates

(ppb)

ALB Chronic Invertabrates

(ppb)

BILLSS-2 2,4-D 6/16/2011 27 13.1 12,500 16,050

HLNSS-4 2,4-D 6/23/2011 17 13.1 12,500 16,050

HLNSS-2 2,4-D 6/23/2011 7.1 13.1 12,500 16,050

HLNSS-4 2,4-D 8/5/2011 9.4 13.1 12,500 16,050

HLNSS-2 Chlorsulfuron 8/25/2011 0.036 0.055 185,000 20,000

HLNSS-4 Diazanon 5/27/2012 0.26 3,700 0.11 0.17

BILSS-2 Malathion 6/16/2011 0.071 2,400 0.3 0.035

HLNSS-1 Malathion 6/23/2011 1.1 2,400 0.3 0.035

BILSS-3 Malathion 8/29/2011 0.16 2,400 0.3 0.035

HLNSS-1 Malathion 8/27/2012 0.031 2,400 0.3 0.035

HLNSS-4 Malathion 8/27/2012 0.015 2,400 0.3 0.035

HLNSS-4 MCPA 7/16/2012 33 90 170 20

• Nitrate detected in 20 of 23 samples

• All nitrate concentrations were <1.6 ppm with a mean concentration of 0.7 ppm

Nitrate Results