Pesticides in Urban Environments - American Chemical Society

Chapter 23

Measurement of Pesticides in Air During Application to Lawns, Trees, and Shrubs in Urban Environments R. A. Yeary and J. A. Leonard

Downloaded by CORNELL UNIV on September 27, 2016 | http://pubs.acs.org Publication Date: February 18, 1993 | doi: 10.1021/bk-1993-0522.ch023

ChemLawn Services Corporation, Columbus, OH 43235

Airborne levels of pesticides and formulation ingredients were measured during and following the mixing, loading, or application of pesticides and fertilizers. Air sampling was conducted according to procedures described in the OSHA Industrial Hygiene Technical Manual. Samples consisted of breathing zone air of pesticide applicators, indoor air of pesticide warehouse facilities and offices, indoor air of residential properties and ambient air of residential properties. Approximately 500 samples were taken in 14 cities in the United States and Canada. Breathing zone airborne pesticide measurements were made for 200 pesticide applicators. Indoor air measurements were made in 82 homes and outdoor ambient air measurements were made at 55 of the homesites. The analytes measured were; acephate, atrazine, ammonia, carbaryl, chlorpyrifos, 2,4-D, diazinon, dicofol, MCPA, pendimethalin and xylene. Monitoring results indicated that most samples (80 percent) were below detectable limits of .001 mg/M . Where analytes were detected, the time-weighted average concentration was less than 10 percent of any established standard. 3

Many pesticide products have odors (e.g., solvents, impurities) that are detectable at trace quantities. Detection of odor commonly leads to the assumption that there is significant exposure from airborne pesticides. This belief is further heightened by the additional assumption that during spray applications of pesticides to lawns, trees, and shrubs, airborne aerosols or mists are generated. To address the issue of inhalation exposure from application of pesticides in urban environments, the ChemLawn Services Corporation has conducted air sampling studies for measurement of pesticides at various locations throughout the United States and Canada. These studies were conducted over a period of three years. We have previously reported on worker exposure during urban application of pesticide to trees and ornamental shrubs (1).

0097-6156/93/0522-0275$06.00/0 © 1993 American Chemical Society

Racke and Leslie; Pesticides in Urban Environments ACS Symposium Series; American Chemical Society: Washington, DC, 1993.

PESTICIDES IN URBAN ENVIRONMENTS

276


MATERIALS AND METHODS Air Sampling And Analysis. Air sampling was conducted according to procedures described in the OSHA Industrial Hygiene Technical Manual (2). Samples for measurement of analytes were collected using preloaded cassettes (SKC Inc., Eighty Four, Pa.) with glass fiber filters, an absorbent layer and support pads through which air was drawn. Charcoal was used as the absorbent medium for pesticides and xylene. Silica gel was used as the absorbent medium for ammonia. Controls included field-spiked and blank filter cassettes. The filter cassettes were analyzed for selected analytes by an accredited industrial hygiene laboratory using high pressure liquid chromatography, gas liquid chromatography or ion selective electrode as appropriate. Recovery rates for spiked media were at least 90 percent. Analytes. The analytes measured were atrazine, acephate, ammonia, carbaryl, chlorpyrifos, 2,4-D, diazinon, dicofol, MCPA, pendimethalin and xylene. Selection of the analytes to be measured at each worksite was dependent on the agronomic program in use at the time of the site-specific study. The Occupational Exposure Limit for each analyte is shown in Table I.

Table I. Occupational Exposure Limits Analyte Acephate Atrazine Ammonia Carbaryl Chlorpyrifos 2,4-D Diazinon Dicofol MCPA Pendimethalin Xylene

Source

ACGIH OSHA OSHA OSHA OSHA OSHA Rohm & Haas OSHA

3

TWA (Mg/M ) NE 5.0 35.0 5.0 0.2 10.0 0.1 (skin) 1.0 NE NE 435.0

NE - Not Established Residential Indoor Air And Outdoor Ambient Air. Residential sampling was performed in and around the homes of company employees at the time of a pesticide application to their lawns, trees or shrubs. Battery operated, high-flow pumps calibrated at a flow of two liters per minute were placed inside the residence in the approximate center of a ground floor room prior to a pesticide application. The pumps were usually


23.

YEARY & LEONARD

Measuring Pesticides in Air During Application


placed on a piece of furniture. They were operated continuously beginning approximately 15 minutes prior to the application and for a period of about six to seven hours. The pumps were calibrated before and after the sampling period using a Buck Calibrator. Where flow rate deteriorated significantly (>1%), the sample was discarded. An additional pump was placed outside the residence approximately 15 feet from the building at ground level or within three feet of the ground. Applicator Breathing Zone Air Monitoring. High-flow (2.0 L/min) sampling pumps were attached to the waistband of the applicators' pants. The collecting filter cassette was attached to the applicators' shirt collar. Sampling began prior to the morning tank mixing and loading activity and continued until the applicator returned to the operating facility at the end of the workday. Each participant maintained an activity log to record actual spray time. Thetimeweighted average (TWA) was calculated on the basis of the total number of hours worked at all activities by dividing the amount of analyte measured by the total number of minutes the sample was collected. Worksite Location. The studies were conducted in 14 cities of wide geographic and climatic diversity. These included: Baltimore, Maryland Buffalo, New York Chicago, Illinois Columbus, Ohio Dallas, Texas Fort Wayne, Indiana Los Angeles, California

Monmouth, New Jersey Montreal, Canada Orlando, Florida Philadelphia, Pennsylvania Tampa, Florida Toronto, Canada Washington, D.C.

Office, Operations Room and Warehouse. The warehouse and/or office measurements were made during the period that mixing and loading of pesticides and fertilizers was taking place and continued during the same day. The sampling equipment was placed in the immediate proximity to a designated containment area for the mixing and loading process. An area adjacent to the office and separated by walls from the warehouse where pesticide applicators have a work station for making telephone calls and reviewing their daily records is designated the operations room for the purpose of this paper. RESULTS AND DISCUSSION Residential Indoor Air Monitoring. The results of the residential indoor air monitoring are shown in Table II. Indoor air monitoring was conducted in 82 homes. Sampling time was approximately 7 hours. The analytes were below detectable limits in 198 of the 224 samples. Carbaryl was the most frequently detected pesticide. The average TWA for the 16 positive carbaryl samples was 0.26 percent of the permissible exposure limit Dicofol has a pungent odor that is often detected after application to ornamental plants but was detectable in only 1 of 63 homes. Xylene is a solvent in the chlorpyrifos product and


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diazinon product purchased and was not detected. It is very likely that xylene, which is diluted with water by a factor of 700 and is subsequendy agitated in a tank vented to the atmosphere, evaporated rapidly following the mixing and loading procedure.

Table II. Residential Indoor Air Monitoring Detection Number Mean Sampling Limit Mg/M Time (Min.) of Homes


Analyte Acephate (T/S) Carbaryl (T/S) Chlorpyrifos 2,4-D Diazinon Dicofol (T/S) Xylene

3

3

3

17 38 10 26 34 63 36

414 414 438 438 414 414 418

2

BDL

3

16 22 10 18 34 62 36

.001 .001 .001 .001 .001 .001 4.35

1

TWA Mg/M

3

.032 (1) .013 (16) -.034 (6)

~

.002 (1)

-

*BDL = Below Detectable Limits. TWA = Time Weighted Average. The number of positive samplesfromwhich the TWA was calculated are shown in parentheses. T/S = Tree and Ornamental Shrub Applications.

2

3

Residential Outdoor Ambient Air. The results of monitoring of residential ambient air are shown in Table HI. Monitoring was conducted at 55 homesites. Sampling time was approximately 7 hours. Ammonia was measured in residential ambient air inasmuch as lawn care applications contained fertilizers with urea as a source of nitrogen. Urea may hydrolyze to ammonia depending upon pH and available moisture. Neither ammonia, malathion nor xylene were detected. Carbaryl was detected at 13 of 28 homesites monitored, and the average TWA was 0.013 mg/M . Both the indoor detections and ambient air detections of carbaryl were made on the same day and from operations out of the same service center. The outdoor temperature was approximately 20°C and the relative humidity was above 90 percent Eight residences had detectable levels of carbaryl in both indoor air and ambient air. It is unlikely that this was operator error in that the plants on these properties also received applications of dicofol and diazinon which were not detected. 3

Applicator Breathing Zone Air. Approximately 200 pesticide applicators were monitored during a workshift of at least eight hours. As shown in Table IV, pesticides were not detected in the breathing zone of 75 percent of the applicators at a sensitivity of 0.001 mg/Μ · None of the TWA values approached the permissible exposure levels suggested for workers in indoor environments. There are no applicable standards for agricultural operations. The Department of Labor has only recently proposed air contaminant standards for agriculture (3). 3


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YEARY & LEONARD

Table ΙΠ. Residential Outdoor Ambient Air Monitoring


Analyte

2

Number of Homesites

BDL

17 12 28 53 34 5 16 30

16 12 15 52 32 5 11 30

Acephate Ammonia Carbaryl Dicofol Diazinon Malathion 2,4-D Xylene l

TWA Mg/M

1

.032 -.013 .006 .004 -.025

—

3

(1) (13) (1) (2) (5)

3

BDL = Below Detectable Limits (.001 mg/M ). TWA = Time Weighted Average for Sampling Period. The number of positive samples from which the TWA was calculated are shown in parentheses.

2

Table IV. Applicator Breathing Zone Air Monitoring

Substance

2

Number Monitored

BDL

22 10 17 76 2 20 25

16 10 9 61 2 7 25

Atrazine Bensulide Chlorpyrifos 2,4-D Dacthal Diazinon MCPA Pendimethalin

_S

_S

Total

201

154

!

2

TWA Mg/M

1

3

.001(6)

—

.005(8) .004(15)

—

.014(13)

—

Average Time Application/ Work Shift (Min.) 163 /509 142 /497 155 /581 180 /493 215 /493 152 /501 147 /490

-

3

BDL = Below Detectable Limits (.001 mg/M ). TWA = Time Weighted Average. The number of positive samplesfromwhich the TWA was calculated are shown in parentheses.

Diazinon was detected in samples from seven of 20 applicators, the highest value being 0.032 mg/M . Both diazinon and chlorpyrifos are cholinesterase inhibiting insecticides. All participants in the study were also monitored for blood cholinesterase activity at three3


279


280


week intervals. All erythrocyte cholinesterase values were within 70 percent of the baseline control value for each individual and thus within the range of normal variation. Though 2,4-D was detected in 15 of 76 samples, the average TWA was barely above the limit of detection and was only 0.04 percent of the OSHA standard. The results for 2,4-D were in general agreement with the finding of Harris and coworkers (4) who found 2,4-D in 5 of 76 air samples taken during home applications of 2,4-D. Two of these coincided with measurable applicator exposure. The overall results for lawn care pesticide applicators were similar to those reported for workers spraying pesticides on trees and shrubs. Of 151 pesticide applicators monitored, 243 of 299 samples (80%) did not have detectable levels of pesticides in breathing zone air samples, and where detectable, levels of pesticides were generally less than 10 percent of the permissible exposure level (1). Office, Operations Room And Warehouse. Eighty two samples were taken either in the office (22), operations room (27) or the warehouse (33) at the 14 cities where these studies were conducted. Only 5 of the 82 samples contained detectable levels of pesticides at a sensitivity of 0.001 mg/m when measured over a period of 8-10 hours (Table V). The highest level of detection was diazinon (0.079 mg/M ) in a warehouse fill area in a makeshift glove box for weighing diazinon in a powder formulation. 3

3

Table V. Office, Operations Room and Warehouse Air Monitoring

Analyte

Number of Facilities

Atrazine Carbaryl CMorpyrifos 2,4-D (Office) (Warehouse) (Operations) Diazinon MCPA Pendimethalin Xylene

1 5 4 8 10 7 3 3 1 7

Mean Sampling Time (Min.) 647 558 596 559 588 574 596 416

3 3 3

583

3

Office 2

ND ND .005 (1) ND --

—

3

ND ND

—

3

TWA (Mg/M ) Operations

ND

1

Warehouse

ND ND ND

ND ND ND

--

-.005 (1) -.073 (2) ND

-.003 (1)

.025 (1) ND ND ND

.0063 (1) ND

1

TWA = Time Weighted Average. The number of positive samples from which the TWA was calculated are shown in parentheses. ND = Below Detectable Limits (.001 mg/M ). Sampling Time Given is for Warehouse.

2

3

3


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YEARY & LEONARD


281

CONCLUSIONS These data demonstrate that airborne concentrations of pesticides following applications in urban environments for control of weeds, insects and diseases of lawns, trees and shrubs are quite low with respect to existing standards for occupational exposures. Pesticides were not detectable (

Pesticides in Urban Environments - American Chemical Society

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