Pesticides in Nursery Runoff Pesticides in Nursery Runoff and Mitigationand Mitigation

(A 319h grant)(A 319h grant)

11J. Gan, W.J. Lao, F. Ernst, L. Wu J. Gan, W.J. Lao, F. Ernst, L. Wu 22D. Haver, J. KabashimaD. Haver, J. Kabashima

33K. Gilbert, J. Newman, B. FaberK. Gilbert, J. Newman, B. Faber

11UC RiversideUC Riverside22UCCE Orange CountyUCCE Orange County33UCCE Ventura CountyUCCE Ventura County

OutlineOutline

Dry weather runoffDry weather runoffStormwater runoffStormwater runoffMitigation practicesMitigation practices

A MultiA Multi--billion Industrybillion Industry

Source: H. Carmen, 2005

A Large Commercial NurseryA Large Commercial Nursery

Dry Weather RunoffDry Weather Runoff

Inflow Rate MeasurementInflow Rate Measurement

Outflow Rate MeasurementOutflow Rate Measurement

Daily Inflow and Outflow RatesDaily Inflow and Outflow Rates(Gallons/day)(Gallons/day)

0

50000

100000

150000

200000

5/28/2005

6/17/2005

7/7/2005

7/27/2005

8/16/2005

9/5/2005

9/25/2005

10/15/2005

11/4/2005

11/24/2005

12/14/2005

1/3/2006

1/23/2006

2/12/2006

3/4/2006

3/24/2006

4/13/2006

5/3/2006

Date

Gal

lons

/day

InflowDischarge

Flow Rate ObservationsFlow Rate ObservationsFlumes + sensors ideal for dry weather runoff monitoringFlumes + sensors ideal for dry weather runoff monitoringDaily inflow rate > outflow rateDaily inflow rate > outflow rateJuly 8, 2005 July 8, 2005 -- Mar. 28, 2006Mar. 28, 2006

2.93 million gallons outflow volume2.93 million gallons outflow volume4.47 million gallons inflow volume4.47 million gallons inflow volumeOutput = 65% inputOutput = 65% inputThe nursery served as a sink under dry weather conditionsThe nursery served as a sink under dry weather conditions

Reduced runoffReduced runoffImproved irrigation practicesImproved irrigation practicesOnOn--site retentionsite retention

•• Reuse of retained waterReuse of retained water•• PercolationPercolation•• EvaporationEvaporation

Water Retention and ReuseWater Retention and Reuse

Bifenthrin Concentrations in RunoffBifenthrin Concentrations in Runoff(ppb, (ppb, µµg/Lg/L))

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

6/23/2

005

6/23/2

005

7/7/20

057/7

/2005

7/14/2

005

7/14/2

005

7/20/2

005

8/3/20

058/1

1/200

58/1

9/200

58/2

4/200

59/2

/2005

9/9/20

059/1

9/200

59/2

3/200

59/2

9/200

510

/7/20

05

10/13

/2005

10/24

/2005

11/4/

2005

11/10

/2005

11/18

/2005

11/23

/2005

12/2/

2005

12/7/

2005

12/15

/2005

12/22

/2005

12/30

/2005

1/4/20

061/1

2/200

61/2

0/200

61/2

6/200

62/2

/2006

2/9/20

062/1

7/200

62/2

3/200

63/2

/2006

3/10/2

006

3/15/2

006

3/23/2

006

3/29/2

006

4/6/20

06

Date

Con

cent

ratio

n (u

g/L

)

InflowDischarge

Weekly Dry Weather Bifenthrin RunoffWeekly Dry Weather Bifenthrin Runoff(mg)(mg)

0

100

200

300

400

500

600

700

800

900

1000

7/19/2

005

8/2/20

058/1

0/200

58/1

8/200

58/2

4/200

59/1

/2005

9/8/20

059/1

8/200

59/1

2/200

59/2

8/200

510

/6/20

0510

/13/20

0510

/18/20

0510

/24/20

0511

/4/20

0511

/10/20

0511

/18/20

0511

/23/20

0512

/2/20

0512

/7/20

05

Date

mg

InflowDischarge

Pesticide Loads ObservationPesticide Loads Observation

No OP was detectedNo OP was detectedPyrethroids were frequently detectedPyrethroids were frequently detected

Bifenthrin always detectedBifenthrin always detectedFenpropathrin, Fenpropathrin, cyhalothrincyhalothrin, cyfluthrin, and , cyfluthrin, and deltamethrin sometimes detecteddeltamethrin sometimes detected

Bifenthrin concentrations higher in outflow than Bifenthrin concentrations higher in outflow than in inflowin inflow

The nursery is a net exporter of bifenthrinThe nursery is a net exporter of bifenthrinBifenthrin is used for RIFA controlBifenthrin is used for RIFA controlBifenthrin is always present in potting mix Bifenthrin is always present in potting mix

Pesticide Loads ObservationPesticide Loads Observation

Bifenthrin concentrations decreased substantially Bifenthrin concentrations decreased substantially during the projectduring the projectDaily bifenthrin load reduction: 98.7%Daily bifenthrin load reduction: 98.7%

Daily bifenthrin load with mitigation = 2.06 mg/dayDaily bifenthrin load with mitigation = 2.06 mg/dayDaily bifenthrin load without mitigation = 163.4 mg/day Daily bifenthrin load without mitigation = 163.4 mg/day

Causes for reduction:Causes for reduction:Reduction in outflow rateReduction in outflow rateReduction in pesticide concentrationReduction in pesticide concentration

•• OnOn--site retentionsite retentionSettling of loose particlesSettling of loose particlesAdsorption to sedimentAdsorption to sedimentInIn--situ degradation

0

0.5

1

1.5

2

2.5

Raw Retained

RawRetained

situ degradation

Stormwater RunoffStormwater Runoff

Stormwater Runoff OutflowStormwater Runoff Outflow

0

1000000

2000000

3000000

4000000

5000000

6000000

7000000

8000000

9000000

10000000

5/28/2005

6/17/2005

7/7/2005

7/27/2005

8/16/2005

9/5/2005

9/25/2005

10/15/2005

11/4/2005

11/24/2005

12/14/2005

1/3/2006

1/23/2006

2/12/2006

3/4/2006

3/24/2006

4/13/2006

5/3/2006

Date

Gal

lons

/day

InflowDischarge

Flow Rate ObservationsFlow Rate ObservationsLarge flumes needed for storm flow monitoringLarge flumes needed for storm flow monitoringStorm runoff overwhelms dry weather runoffStorm runoff overwhelms dry weather runoffJuly 8July 8--March 31:March 31:

Dry weather total output: Dry weather total output: 4.1 million gallons4.1 million gallonsStorm total output: Storm total output: 41.4 million gallons41.4 million gallonsStorm runoff: Storm runoff: 90.9% of total output90.9% of total outputDry weather runoff: Dry weather runoff: 9.1% of total output9.1% of total output

Bifenthrin in RunoffBifenthrin in Runoff(ppb, (ppb, µµg/L)g/L)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

6/23/2

005

6/23/2

005

7/7/20

057/7

/2005

7/14/2

005

7/14/2

005

7/20/2

005

8/3/20

058/1

1/200

58/1

9/200

58/2

4/200

59/2

/2005

9/9/20

059/1

9/200

59/2

3/200

59/2

9/200

510

/7/20

05

10/13

/2005

10/24

/2005

11/4/

2005

11/10

/2005

11/18

/2005

11/23

/2005

12/2/

2005

12/7/

2005

12/15

/2005

12/22

/2005

12/30

/2005

1/4/20

061/1

2/200

61/2

0/200

61/2

6/200

62/2

/2006

2/9/20

062/1

7/200

62/2

3/200

63/2

/2006

3/10/2

006

3/15/2

006

3/23/2

006

3/29/2

006

4/6/20

06

Date

Con

cent

ratio

n (u

g/L

)

InflowDischarge

Weakly Bifenthrin Runoff at Outlet 2 Weakly Bifenthrin Runoff at Outlet 2 (mg)(mg)

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

7/19/2

005

8/2/20

058/1

0/200

58/1

8/200

58/2

4/200

59/1

/2005

9/8/20

059/1

8/200

59/1

2/200

59/2

8/200

510

/6/20

0510

/13/20

0510

/18/20

0510

/24/20

0511

/4/20

0511

/10/20

0511

/18/20

0511

/23/20

0512

/2/20

0512

/7/20

0512

/15/20

0512

/22/20

0512

/30/20

051/4

/2006

1/12/2

006

1/20/2

006

1/26/2

006

2/2/20

062/9

/2006

2/17/2

006

2/23/2

006

3/2/20

063/1

0/200

63/1

5/200

63/2

3/200

63/2

9/200

64/6

/2006

Date

mg

InflowDischarge

Pesticide Loads ObservationPesticide Loads Observation

Bifenthrin concentrations in storm runoff were higher Bifenthrin concentrations in storm runoff were higher than in dry weather runoffthan in dry weather runoffBifenthrin loads in storm runoff overwhelms dry Bifenthrin loads in storm runoff overwhelms dry weather runoffweather runoffJuly 8July 8--March 31:March 31:

Total dry weather export: Total dry weather export: 2,104 mg2,104 mgTotal storm export: Total storm export: 67,029 mg67,029 mgStorm runoff loads: Storm runoff loads: 97% of total export97% of total export

Storm runoff features:Storm runoff features:High initial concentrationsHigh initial concentrations

0

20

40

60

80

100

120

0min 40min 7h

Mitigation PracticesMitigation PracticesIrrigation RunoffIrrigation Runoff

Easy to manageEasy to manageEfficient irrigation practicesEfficient irrigation practicesRetentionRetention

Retention of particles and organic matterRetention of particles and organic matterPercolationPercolationEvaporationEvaporationNatural degradationNatural degradationReuse of retained waterReuse of retained water

Loose potting mix managementLoose potting mix managementVegetative filters in ditchesVegetative filters in ditchesCoir filters?Coir filters?

Mitigation PracticesMitigation PracticesStorm RunoffStorm Runoff

(Extremely) difficult to manage(Extremely) difficult to manageCatch and retain runoff from small stormsCatch and retain runoff from small storms

““First flushFirst flush””

PrePre--storm preparation:storm preparation:Loose potting mix managementLoose potting mix managementContainers away from ditches?Containers away from ditches?Clean up ditchesClean up ditchesMinimize pesticide use in winter monthsMinimize pesticide use in winter monthsAlternative pesticides in winter monthsAlternative pesticides in winter months

0

20

40

60

80

100

120

0min 40min 7h

AcknowledgementAcknowledgementThe noThe no--name nurseryname nurseryEPA 319(h) programEPA 319(h) programSanta Ana RWQCB Santa Ana RWQCB

(Doug (Doug ShibberuShibberu))

CA Department of Pesticide RegulationCA Department of Pesticide Regulation(PUR databases)(PUR databases)