1

Resmethrin & PBO Residues 

Detected Following ULV 

Applications

Roy W. Meyer

New Jersey Department of 

Environmental Protection

Pesticide Control Program

Roy.meyer@dep.state.nj.us

Scourge insecticide

EPA Registration No. 432-716

(Used throughout 2003-2005)

• Paramus Catholic High 

School - Paramus

• Approximately 1 3/4 

acres treated

• Rate 4 oz/min x 2 1/2 

minutes

– 10 ounces

• 3 of 4 sites in Saddle 

River

– rate 20 ft/min

• Bergen County Utility 

Authority - Little Ferry 

• Approximately 7 acres 

treated

• Rate 4 oz/min x 3 

minutes

– 12 ounces

• 2 sites within spray area

• 1 site across pond

– ~ 1550 ft distant from 

treatment area

Paramus Catholic High School - Saddle River - Site 1 

Site 1 

A 

C 

B 

D 

Spray Route/River Flow 

Table 1. 2003 Mosquito Project Sampling Results

Site 1 - Paramus Catholic High School - Saddle River

Time after Application 0 Minutes 15 Minutes 30 Minutes 45 Minutes

Point A

Pesticides:

Resmethrin ND ND ND ND

PBO ND ND ND ND

Point B

Pesticides:

Resmethrin ND ND ND ND

PBO ND 0.24 ug/l 0.36 ug/l Identified

Point C

Pesticides:

Resmethrin ND ND ND ND

PBO ND 0.39 ug/l 0.27 ug/l 0.25 ug/l

Point D

Pesticides:

Resmethrin ND ND ND ND

PBO ND ND ND ND

Background 

Resmethrin ND

PBO 0.34 ug/l
2

Little Ferry - Bergen County Utility Authority - Site 2

Site 2 

A 

B 

C 

 Spray Route 

Site 2 - Little Ferry - Lake near Treatment Plant

Time after Application 0 Minutes 30 Minutes 60 Minutes 90 Minutes

Point A

Pesticides:

Resmethrin ND ND ND ND

PBO ND ND ND ND

Point B

Pesticides:

Resmethrin ND ND 0.47 ug/l 0.45 ug/l

PBO ND 0.50 ug/l 0.38 ug/l 0.34 ug/l

Point C

Pesticides:

Resmethrin ND 0.56 ug/l 0.41 ug/l 0.46 ug/l

PBO ND 0.36 ug/l ND 0.35 ug/l

Background 

Resmethrin ND

PBO ND

0

0.1

0.2

0.3

0.4

0.5

0.6

ug/l

Levels Identified 30 Minutes Post-Application

Comparison of Detected Residue Levels

Resmethrin PBO

Resmethrin 0.56 0.021 0.005 0.043

PBO 0.315 0.43 0.343 0.005 0.28

Saddle River BCUA Spectacle 

Pond (LI)

Lake 

Ronkonkoma 

(LI)

Westchester 

Maximum 

Predicted 

2004 - Paramus Catholic High School - Saddle River
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2004 Mosquito Project Sampling Results

Application on October 5, 2004

Time measured in hours after application 

Site 1 - Saddle River

Time 0 Time 1 Time 2 Time 3 Time 24 Time 48

Point A1

Pesticides:

Resmethrin ND ND ND ND ND ^

PBO ND ND ND ND ND ^

Point A2

Pesticides:

Resmethrin ND ND ND ND ND ND

PBO ND 0.006 ug/cm2 ND ND ND ND

Point A3

Pesticides:

Resmethrin ND ND ND ND ND ND

PBO ND 0.003 ug/cm2 ND ND ND ND

Point B1

Pesticides:

Resmethrin ND ND ND ND ND ^

PBO ND ND ND ND ND ^

Point B2

Resmethrin ND ND ND ND ND ND

PBO ND 0.12 ug/cm2 ND ND 0.0011 ug/cm2 ND

Point B3

Pesticides:

Resmethrin ND ND ND ND ND ND

PBO ND 0.003 ug/cm2 ND ND ND ND

Point C

Pesticides:

Resmethrin * ND ND ND ^ ^

PBO * 0.0022 ug/cm2 ND ND ^ ^

* A sample was not collected at this time interval.

^ Filter paper was placed at the sampling location for this time interval, but had been removed when we returned to co

Paramus Catholic High School

August 2005

Table 1. August 17, 2005 Sampling Results

Moving Application Source

Paramus Catholic High School - Paramus

Residues in ng/cm2

Application Path 0' 150' 300'

Distance from

Application Pathway

20'

Resmethrin 2 ND ND

PBO 13 110 7

Fluorescence No No No

100'

Resmethrin ND ND ND

PBO 28 14 6

Fluorescence No No No

Samples collected 15 minutes after application

Paramus Catholic High School

August 2005
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Table 2. August 17, 2005 Sampling Results

Stationary Application Source

Parmaus Catholic High School - Parmaus

Residues in ng/cm2

Distance Sample ID Resmethrin PBO

4' S1 4 90

8' S2 4 120

12' S3 3 60

16' S4 3 140

16' S6 ND 13

16' S10 2 120

20' S5 11 670

25' S7 3 78

25' S8 5 480

25' S9 7 550

Campgaw Mountain Reservation

September 2005

Table 3. September 22, 2005 Sampling Results

Campgaw Mountain Reservation Parking Lot - Mahwah

Residues in ng/cm2

Distance From Application 150' 200-250' 300-375' 400-575'

Filter Paper - Blue

Pesticides:

Resmethrin < 0.68 ND ND --

PBO 1.5 ND ND --

Filter Paper - Yellow

Pesticides:

Resmethrin -- 0.91 ND --

PBO -- < 0.77 < 0.77 --

Filter Paper - Orange

Pesticides:

Resmethrin < 0.68 -- -- < 0.68

PBO 16 -- -- < 0.77

Aluminum Sheet - Swabs

Pesticides:

Resmethrin ND ND ND ND

PBO ND ND ND ND

Campgaw Mountain Reservation

October 2005
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Table 4. October 19, 2005 Sampling Results

Campgaw Mountain Reservation Parking Lot - Mahwah

Residues in ng/cm2

Distance From Application 25' 50' 100' 175' 250'

Filter Paper - Blue

Pesticides:

Resmethrin ND ND ND ND ND

PBO 0.45 0.48 0.42 2.6 1.6

Filter Paper - Yellow

Pesticides:

Resmethrin ND ND ND ND ND

PBO 9.8 12 2.3 0.51 1.1

Van Swabs Resmethrin - ND, PBO - ND

Filter Paper - Orange

Pesticides:

Resmethrin ND ND ND ND ND

PBO 5.5 1.4 1.5 1.7 1.2

Mean Values

Pesticides:

Resmethrin ND ND ND ND ND

PBO 5.25 4.63 1.41 1.60 1.3

Std Dev 4.680 6.402 0.943 1.048 0.265

Issues related to lack of consistent 

Resmethrin detections

Possible explanations:

• Sample preparation and analytical 

error(s)

– Analytical methods & previous laboratory 

experience demonstrates ability to detect 

analytes

– PBO detected but not Resmethrin

– QA/QC Spike recoveries due to material in 

vial, not on filter paper

Controlled Field Tests Confirm 

Methodology

Issues related to lack of consistent 

Resmethrin detections

• Sampling error(s)

– Requires all or most samplers to err in a 

consistent fashion - Examined & Eliminated

• Matrix interference

– Binding with materials in filter paper

– Similar problems with water samples -

Laboratory And Field Tests Eliminate 

Interference As A Factor

• Fluorescent Tracer

– Inconsistent Results

– Utility As An “Onsite” Tool Appears Limited

Issues related to lack of consistent 

Resmethrin detections

• Residue concentration

– Only detections of resmethrin occurred in BCUA pond 

Deposition Experiments On Aluminum Foil Or 

Vehicle Unproductive

– Residue concentration assumptions based on scientific 

literature examining malathion Difference In A.I. 

Significant

– ULV method of application Conditions Have 

Significant Influence - Deposition Rates Vary 

Significantly

– Levels of resmethrin residues below detection levels of 

analytical instruments MUCH GREATER VARIATION 

THAN INITIALLY EXPECTED!
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• 2007 Location:

• Hamilton Police 

Department Firing 

Range - Electronics 

Road site

• Adjacent to areas of 

high mosquito 

populations

• Routinely treated by 

County of Mercer, 

Dept. Transportation 

& Infrastructure, 

Mosquito Control 

Division

Hamilton Township Firing Range

Electronics Road

August 16, 2007

• Scourge insecticide

– EPA Reg. No. 432-716

• Active Ingredients

– Resmethrin - 4.14%

– Piperonyl Butoxide – 12.42%

• Rate 6 oz/min x 3 minutes

– 18 ounces applied

• Temperature – 79oF

• Relative Humidity – 72%

N = 8

PBO 23.8 2.8 – 49.0

Resmethrin 0.135 ND – 0.62

Pesticides:

Hanging Filter Paper

N = 13

PBO 29.308 11.0 – 45.0

Resmethrin 0.268 ND – 4.0

Pesticides:

Ground Filter Paper

Residues in ng/cm Mean Range 2

Electronics Road, Hamilton

Table 1. August 16, 2007 Sampling Results

Hamilton Township Firing Range

Electronics Road

October 4, 2007

• Scourge insecticide

– EPA Reg. No. 432-716

• Active Ingredients

– Resmethrin - 4.14%

– Piperonyl Butoxide – 12.42%

• Rate 6 oz/min x 2 minutes

– 12 ounces applied

• Temperature – 75oF

• Relative Humidity – 84%
7

N = 8

PBO 3.0 1.4 – 7.9

Resmethrin 0.346 ND – 0.62

Pesticides:

Hanging Filter Paper

N = 4

PBO 24.25 16.0 – 33.0

Resmethrin 1.358 0.66 – 2.5

Pesticides:

Ground Filter Paper

Residues in ng/cm Mean Range 2

Electronics Road, Hamilton

Table 2. October 4, 2007 Sampling Results

Proposed Research

• Continued examination of ground 

applications of adulticides containing 

Resmethrin

– Distance

– Time

– Deposition

• Research the role(s) played by climate 

conditions

• Examination of fate & transport 

mechanisms

• Detections compared to Efficacy