ArticlePDF Available

Determination of glyphosate through passive and active sampling methods in a treated field atmosphere

Authors:

Abstract and Figures

The study was carried out to determine the atmospheric residues of glyphosate (N-phosphonomethylglicine) using both passive and active sampling methods in Malaysia's tropical weather conditions. The field was treated with Roundup (Monsanto) @ 2L ha -1 using Mistblower (Solo 412). Glyphosate was sampled in 12 h day time pre and post-spray sampling events using three simple and low-cost passive air samplers (cotton gauze, cellulose filter, and PUF) and active sampling using PUF plug and quartz filter cartridges. In pre-spray sampling event, no glyphosate detection was shown in both passive and active sampling. On the other hand, post-spray passive samples data revealed that only cotton gauze among the three passive air samples showed detection in both post-spray events during which the first post-spray (2.49 ng/cm 2) showed significantly higher residue measurement than that of second post-spray period (0.84 ng/cm 2). In active sampling, however, no glyphosate residue was detected in any of the PUF plug samples but detected only in quartz filter samples, revealing that glyphosate is associated with particles rather than vapour in the air. The highest concentration of glyphosate (42.96µg/m 3) was measured in the air at operator's breathing zone during the 25 min spray application period. In the post-spray active sampling periods, glyphosate residue was significantly far below compared to the spray period concentration. Furthermore, in paired comparison between active and passive sampling methods in terms of residue uptake performance, passive sampling showed significantly better performance than the active sampling method in this study.
Content may be subject to copyright.
African Journal of Agricultural Research Vol. 6(17), pp. 4010-4018, 5 September, 2011
Available online at http://www.academicjournals.org/AJAR
DOI: 10.5897/AJAR11.533
ISSN 1991-637X ©2011 Academic Journals
Full Length Research Paper
Determination of glyphosate through passive and
active sampling methods in a treated field atmosphere
Md. Mahbub Morshed1, Dzolkhifli Omar1*, Rosli B. Mohamad2 and Samsuri B. Abd. Wahed3
1Toxicology Laboratory, Department of Plant Protection, Faculty of Agriculture, University Putra Malaysia, 43400
Serdang, Selangor D. E., Malaysia.
2Department of Crop Sciences, Faculty of Agriculture, University Putra Malaysia, 43400 Serdang, Selangor D. E.,
Malaysia.
3Department of Land Management, Faculty of Agriculture, University Putra Malaysia, 43400 Serdang, Selangor D. E.,
Malaysia.
Accepted 30 May, 2011
The study was carried out to determine the atmospheric residues of glyphosate (N-
phosphonomethylglicine) using both passive and active sampling methods in Malaysia’s tropical
weather conditions. The field was treated with Roundup (Monsanto) @ 2L ha-1 using Mistblower (Solo
412). Glyphosate was sampled in 12 h day time pre and post-spray sampling events using three simple
and low-cost passive air samplers (cotton gauze, cellulose filter, and PUF) and active sampling using
PUF plug and quartz filter cartridges. In pre-spray sampling event, no glyphosate detection was shown
in both passive and active sampling. On the other hand, post-spray passive samples data revealed that
only cotton gauze among the three passive air samples showed detection in both post-spray events
during which the first post-spray (2.49 ng/cm2) showed significantly higher residue measurement than
that of second post-spray period (0.84 ng/cm2). In active sampling, however, no glyphosate residue was
detected in any of the PUF plug samples but detected only in quartz filter samples, revealing that
glyphosate is associated with particles rather than vapour in the air. The highest concentration of
glyphosate (42.96µg/m3) was measured in the air at operator’s breathing zone during the 25 min spray
application period. In the post-spray active sampling periods, glyphosate residue was significantly far
below compared to the spray period concentration. Furthermore, in paired comparison between active
and passive sampling methods in terms of residue uptake performance, passive sampling showed
significantly better performance than the active sampling method in this study.
Key words: Glyphosate, active sampling, passive sampling, atmospheric residue.
INTRODUCTION
Glyphosate (N-phosphonomethylglicine) is a broad-
spectrum, foliar-applied herbicide used to kill unwanted
plants in a wide variety of agricultural crops, lawn and
garden, aquatic, and forestry situations (Humphries et al.,
2005). Glyphosate is registered in more than 130
countries and is believed to be the world’s most heavily
used pesticide (Duke and Powles, 2008), with over 600
thousand tonnes used annually (CCM International,
2009). Based on the registration eligibility data on
toxicology and exposure study (USEPA, 1993), glyphosate
*Corresponding author. E-mail: zolkifli@agri.upm.edu.my.
is under toxicity category III (low toxicity). Moreover, poor
absorption through skin and rapid elimination of
glyphosate upon normal exposure (WHO, 1994) might
convince the occupational safety regulators not to set any
occupational exposure limits for glyphosate. However,
workers in a variety of occupations on exposure to
glyphosate, develops acute illness. It has been revealed
that glyphosate exposure was reported as the third most
commonly-reported cause of pesticide illness among
agricultural workers in California (Cox, 1995). In Malaysia,
glyphosate is the predominant herbicide used in different
cropping systems through motorised knapsack sprayers
in low volume spray (increased herbicide concentration)
for increased herbicide efficacy. This intensive use of
glyphosate has resulted into serious contamination of the
environment because substantial amount of applied
pesticides have been shown to become airborne during
and after application (Seiber et al., 1980). These airborne
residues present a potential exposure route for field
workers and other individuals dwelling close to
agricultural sites.
Unlike the sampling of solid and liquid matrices, air
sampling has always posed unusual challenges because
of the ever changing nature of the components in the
atmosphere. However, understanding the physical
properties of the pesticide (that is, primarily its vapour
pressure) and environmental conditions is the key to the
selection of an appropriate field sampler and its sampling
strategy (Woodrow et al., 2003). In the atmosphere,
pesticides are distributed between particle and vapor
phases based on the vapor pressure of the chemical,
ambient temperature, and concentration of suspended
particulate matter in the air (Gioia et al., 2005). To
determine the residue level in air, both passive and active
sampling methods are commonly used. Active sampling
enable the pesticides present in the air to be trapped by
pumping air through filter and solid adsorbent media
(Tadeo, 2008), whereas passive sampling methods are
conceptually simple. It is based on free flow of analyte
molecules from the sampled medium to a collecting
medium resulting from different physical principles
(Gorecki and Namiesnik, 2002). Numerous passive air
samplers are being used commercially and all of them
are designed to perform sampling keeping various factors
in mind, including, the matrix (air, water, soil), physico-
chemical properties of the target analytes, sampling
duration, environmental variability, cost and easy
availability (Seethapathy et al., 2007). Despite having
some limitations (possible environmental effects on
analyte uptake), passive samplers could be an attractive
alternative to more established sampling procedures due
to its simplicity and cost-effectiveness (Kot-Wasik et al.,
2007)
In Malaysia, several efforts have been made over the
years to determine glyphosate in the environmental
samples (soil and water) but the air compartment is still
overlooked. Moreover, very little information exists in the
literature on studies quantifying glyphosate residues in
the air following spray application. Therefore, the
objective of this study was to measure the airborne
residue present during and after glyphosate application in
the field.
MATERIALS AND METHODS
Experimental site
The study was conducted from February to April, 2009 at field 2
located inside the University Putra Malaysia (UPM), and the test
plot size was 1000 m2 which was a weedy harvested corn field. The
site is bit down compared to the surrounding area. It is completely
open to the west and south where prevailing winds originate, and is
Morshed et al. 4011
not adversely affected by natural trees or shelterbelts on this side.
North of the site is a hay field which extends for 0.2 km before the
start of the urban area. East of the site has office building and some
shed housing facilities for research studies. No fields in close
proximity to this site were treated with glyphosate for pre-seeding,
post-emergent or pre-harvest weed control.
Glyphosate application
Glyphosate herbicide 41% a.i. (Roundup, Monsanto Sdn. Bhd.,
Malaysia) was applied with a calibrated mist blower (Solo Master
412) set at a discharge rate of 0.64 L min-1. Glyphosate was applied
at a field dosage rate of 2 L ha-1 with a spray volume of 160 L.
Spray droplet diameter of this sprayer were measured using
microscope fitted with Porton G12 Graticule , as described by
Matthews (2000). The estimated VMD (volume median diameter)
and NMD (number median diameter) for spray droplet size were 67
and 35.5 µm respectively, and these droplets diameters are
considered as fine droplets (Matthews, 1999).
Air sampling procedures
Three types of passive air samplers with an exposed surface area
of roughly 16 cm2, namely Cotton gauze (Gasmed Sdn. Bhd.,
Malaysia) , Cellulose filter patches (Whatman grade 41, England),
and Polyurethrane Foam(PUF) (SKC Inc., USA) were used for
passive air sampling and each type of samplers was taped on five
surfaces of an identical dimensions foil-covered box (15x15x15cm)
vertically on west (W), East (E), North (N),South (S), and
horizontally on Top (T). These boxes were placed 1 m above the
ground surface at three randomly selected points nearer to
downwind edges of the test plot.
Active sampling was done using field air sampling pump (Model
1067) supplied by Supelco, USA calibrated to a flow rate of 10L
min-1 using bubble flow meter. The sampling pump was connected
by tygon tube to polyurethane foam (PUF) plug cartridge (ORBOTM
1000, Supelco, USA) containing 0.022 g/cm3 density PUF plug in
the glass housing, fitted in front with a Quartz fibre filter cartridge
(Supelco, USA). The PUF plug will work mainly for the vapour and
the quartz filter for particulate phase of airborne glyphosate (Van
Dijk and Guicherit, 1999). After starting sampling, the pump
operation was observed for a short time to make sure that it is
operating correctly. The pump was powered by electricity through
long extension cable to avoid fluctuations in the pump flow rate that
have a significant effect on measurement accuracy when air is
sampled.
Personal air sampling is done to determine the concentration
level that a spray worker is exposed to during a full work shift or
task by measuring the breathing zone concentration of the worker.
Battery-operated personal air sampling pump (Model PAS-500,
Supelco Inc. USA) calibrated to a flow rate of 0.3 L min-1 was used
during spraying. The sampling pump was fixed at the sprayer’s
waist belt and the sampling head fitted with PUF plug and quartz
filter cartridges (Supelco, USA) was attached at sprayer’s collar
bone area in downward position to cover the breathing zone. The
duration of spraying was recorded using a stopwatch.
Sampling frequency and duration
Air sampling was carried out in 12 h day time from 6:30 am to 7 pm
at 4 h interval which was as follows: 4 h pre-spray, during spray (25
min), and post-spray periods (0 to 4 and 4 to 8 h). After sampling,
active samplers (PUF and Quartz filter cartridges) were caped and
passive samplers were collected in centrifuge falcon tubes. All
samples were put in ice box at reduced temperature for transport.
4012 Afr. J. Agric. Res.
Figure 1. Linear calibration curve for glyphosate (N = 9; Y = 7.94 e+6 x + 4.43 e+5 and correlation coefficient r2 = 0.999).
Micrometeorological measurements
Air temperature and wind velocity were recorded on ‘sampling data
sheet’ at every one hour during sampling period by using Thermo-
Anemometer (Extech Instruments, USA). Relative humidity was
also measured at same intervals using Humidity Indicator (Airguide
Instrument Co., USA). During the period wind directions, cloud
cover, and incidence of rain were also noted.
Chemical analysis
Preparation of standard solution and curve
Standard stock solution (400 ppm) was prepared by dissolving
0.004 g glyphosate standard (Sigma-Aldrich, USA. purity 99.7%) in
10 ml 0.025 M sodium borate buffer (pH 9) solution. Nine working
standards of 10.0, 5.0, 2.0, 1.0, 0.5, 0.1, 0.05, 0.01 and 0.005 ppm
were prepared taking the corresponding aliquots from the stock
solution followed by dilution with sodium borate buffer for the
preparation of standard curve to estimate the linearity and
sensitivity of response. Prior to HPLC injection, each working
solutions was pre-column derivatized with a derivatizing agent
(0.002M FMOC-Cl) as described in the pre-column derivatization
step. The lowest calibration level (LCL), which runs on an
instrument with acceptable response (area) is 0.005 ppm. Standard
curve (Figure 1) for glyphosate was found to be linear over the
above range through the evaluation of the correlation coefficient,
which was 0.999. Chromatogram of working standard solution of
glyphosate (10.00 ppm) was shown in Figure 2.
Sample preparation
The sample preparation method was done according to ‘Method
PV2067’ with some modification as proposed by Occupational
Safety and Health Administration (OSHA) analytical laboratory,
USA. Both active and passive samplers were carefully transferred
to 50 mL centrifuge tubes by clean tweezers. 10 ml borate buffer
was added to each tube and then the tubes were capped and
allowed to stand for 30 min to soak samples completely. The
centrifuge tubes were placed on an orbital shaker at 200 rpm for 1 h
followed by ultra sonication (Cole Parmer, USA) for 2 h to desorb
the analyte.
Pre-column derivatisation
The derivatizing agent (0.002M FMOC-Cl) was prepared by adding
0.1293g 9-florenylmethoxycarbonyl chloride (obtained from ACROS
Organics, USA; purity 98%) in 250 ml acetone. Before injecting into
HPLC, 1 mL aliquot of each sample extract was transferred in a
silanized vial and derivatized with 1 mL of derivatizing agent to
produce a highly florescent derivative. The vials were shaken to mix
for 30 sec on a mini-shaker and subsequently allowed them to sit at
room temperature in a dark place for 30 min. Then 1 mL of each
sample was transferred in HPLC vial and subsequently labeled and
injected to HPLC-FD for analysis.
HPLC systems
HPLC (High performance liquid chromatography) was consisted of
Morshed et al. 4013
Figure 2. Chromatogram of glyphosate obtained at 10 ppm standard concentration with the recommended HPLC-Florescence
conditions.
Waters 600 controller pump equipped with Waters 717 auto
sampler and a florescence detector (Waters 4174). The detector
was set with an emission wavelength of 320 nm and an excitation
wavelength of 206 nm that was operated in single channel mode
with photomultiplier gain at 1, attenuation at 64 and output data
sensitivity (EF) at 5000.. The stationary phase was 250 mm × 4.6
mm i.d A0 Hypersil NH2 column (APS-2) and the mobile phase
was comprised of 50% Acetonitrile and 50% Phosphate buffer
(0.05M Potassium phosphate monobasic KH2PO4 adjusted to pH
6.0 with 7N KOH). The mobile phase flow rate (isocratic) was 1
ml/min. All the solvents and solutions used in the mobile phase
were previously filtrated and degassed by ultrasonic application.
The injection volume was 25.0 µL. Total sample run time was 10
min and analyte retention time was 5.6 min.
Fortification and recovery studies
The percentage of analyte recovery from fortified samples generally
represents the extraction efficacy of the method. Fortification was
done in triplicates by applying 100µL of three spiking concentrations
(1.0, 5.0 and 10.0 ppm) over the surface of three fresh unused
samplers (cotton gauge, cellulose filter, and PUF). Then the fortified
(spiked) samples were capped and allowed to keep at 4°
C inside
freeze drawer overnight to equilibrate. The following day, the
fortified samples were extracted and analyzed to HPLC-FD as
same as field samples. Mean recovery percentages from fortified
samples were comprised between 88.8 to 97.2% with a relative
standard deviation (RSD) value of 4 to 6% (Table 1).
Chromatogram of glyphosate fortified at the concentration of 10.0
ppm showed the same peak retention time (5.6 min) as standard
peak (Figure 3).
Limit of Detection (LOD) and Limit of Quantitation (LOQ)
determination
The LOD and LOQ were determined via linear regression method
using linear calibration curve of glyphoshate established at 5
concentration levels with three replicates (ICH, 1996). The LOD for
this method was 0.015 ug ml-1 and the LOQ was determined to be
0.05 ug ml-1.
QC/QA considerations: Laboratory and solvent blanks were
prepared and extracted as same as the field samples which
showed no contamination in solvent and samplers. One field blank
sample for every 15 samples was used for analysis along with the
field samples. All field blank samples were below the analytical limit
of detection (LOD) for glyphosate tested.
Statistical analysis
The study was repeated three times in the same location. Data
collected were analyzed following analysis of variance (ANOVA)
technique under RCBD (factorial) experimental design and means
separation were done by Turkey’s Studentized range (HSD) using
statistical analysis system (SAS). Differences were considered
significant at p<0.05.
RESULTS AND DISCUSSIONS
During the entire sampling period, the weather was clear
and sunny. Temperatures were warm, ranging from 82 to
97°
F. Relative humidity ranging from 84 to 55% was
observed. However, relative humidity was high in the
morning and evening, and decreased as temperature
increased in the mid-day periods. Wind velocity was
almost same throughout the day blowing predominantly
from south and south-west direction, ranging between 2
to 5 mil/h. However, there was no incidence of rainfall on
the sampling days during the study period.
4014 Afr. J. Agric. Res.
Minutes
Fluorescence
Figure 3. Chromatogram of glyphosate obtained at 10 ppm fortification concentration with the recommended HPLC-Florescence
conditions.
Table 1. Percent recovery (mean± S.D.) and relative standard deviation (% RSD) for the glyphosate fortified samples (N = 27).
Compound
Fortification concentration (ppm) Fortification level (µg/sample) % mean recovery ± S.D. % RSD
Glyphosate
1.0 0.1 88.8 ± 5.75 6.61
5.0 0.5 98.7 ± 4.28 4.31
10.0 1.0 97.2 ± 4.50 4.66
Passive air samplers
The results for each passive air sampler showed very
little amount of glyphosate detection only on cotton gauge
samples as summarized in Table 2. Since glyphosate has
no significant vapour pressure and therefore, the loss of
glyphosate to the atmosphere via volatilization from
treated surfaces is nonexistent (Franz et al., 1997). The
main emission pathway for non-volatile particulate-
phased compounds like glyphosate into atmosphere
occurred through wind erosion process of dust particles
on treated surfaces loaded with pesticides (Van Dijk and
Guicherit, 1999). In this study, pre-spray air sampling
was taken for 4 h period prior to spraying and glyphosate
was not detected in any of the three samplers in this pre-
event sampling. The absence of detection at pre-spray
sampling in the morning could be due to the complete
removal of residual atmospheric glyphosate via wet
deposition mainly by night dew/fog, since glyphosates
low Henry’s Law Constant (4.6 × 10-10 Pa m3 mol-1)
indicates that it tends to partition in water versus air
(Franz et al., 1997) and thereby efficiently removed from
the air (Chang et al., 2011). On the other hand, post-
event sampling was carried out in 8 h periods with an
interval of 4 h that started immediately after completion of
spraying, and among the three passive samplers, very
little glyphosate was detected mainly on cotton gauge
passive samplers in both post-spray sampling periods.
However, glyphosate was also detected on the PUF
samples only in the first post-spray sampling event (0 to 4
h periods) that was found below the limit of quantitation
(LOQ) levels and in contrast, no glyphosate was detected
on cellulose filter samples in both post-spray sampling
periods. The amount of glyphosate deposition by cotton
Morshed et al. 4015
Table 2. Glyphosate residue amount mean ± S.D deposited on three passive air samplers before and after application in the treated
field air.
Passive air
samplers Samplers orientation
Deposition amount (ng/cm2)
Pre-spray Post-spray
4 h 0-4 h 4-8 h 8 h TWA
PUF
West ND <LOQ
b
ND -
East ND <LOQ ND -
North ND <LOQ ND -
South ND <LOQ ND -
Top ND <LOQ ND -
Average - - -
Cellulose filter
West ND ND ND -
East ND ND ND -
North ND ND ND -
South ND ND ND -
Top ND ND ND -
Average - - - -
Cotton gauge
West ND 3.42± 1.11ab 1.95± 0.24a 2.68±0.67a
East ND 1.79± 0.68ab <LOQb 0.89±0.34b
North ND 1.97 ± 0.65ab <LOQb 0.98±0.32b
South ND 4.16± 0.70a 2.25± 0.47a 3.20±0.58a
Top ND 1.12± 0.92b NDb 0.56±0.46b
Average - 2.49
± 1.12
0.84
± 1.03
1.66
± 1.07
a TWA, time-weighted average = sum of the products of concentration and time for each sampling period, divided by total sampling time. b
<LOQ = below limit of quantitation. Values followed by the same letter (s) column wise, are not significantly different at (P < 0.05). Samples that
produced undetected results have been assigned as ‘ND’.
gauze samplers could be explained by the findings of
OECD (1997) which recommended cotton fabrics for
trapping particles constructed with layers of cotton
surgical gauze as they are porous enough and have
uneven surfaces that help to retain the particles landing
on it. In first 0 to 4 h post-spray event, cotton gauze
samples yielded higher average glyphosate deposition
(2.49 ng/cm2) than that of second 4 to 8 h post spray
sampling event (0.84 ng/cm2). Obviously, the low levels
of glyphosate detection may account for its insignificant
post-application volatilization from treated surfaces.
Furthermore, once glyphosate had been sprayed, the
resulting fine pesticides particles tends to adsorbed onto
dust particles present in the air and subsequently
partitioned to particulate phase in the atmosphere.
Therefore, the nature and concentration of dust particles
in the air would determine the atmospheric loading as
glyphosate in the air is associated with particulate matter
(dust), assuming that this particulates are removed by
gravitational settling or wind erosion. But this atmospheric
loading into particles is dependent upon many factors in
which environmental factors (such as wind speed,
temperature and humidity) are of importance (Van Dijk
and Guicherit, 1999). However, in the tropical weather of
Malaysia, prevailing high temperature and humidity as
well as high precipitation plays very important role in
glyphosate atmospheric deposition. The amount of dust
particles in the air is reduced as a result of high
atmospheric humidity and frequent precipitation events
(UN-ECE, 1979). This resulted to lower levels of atmos-
pheric glyphosate deposition.
In addition to the above findings, the glyphosate
detection was showed in higher amount on cotton gauze
samplers oriented on south approach (4.16 and 3.42
ng/cm2) followed by west (2.24 and 1.95 ng/cm2) in post
sampling periods indicating the correlation of wind
movement with atmospheric deposition of glyphosate
during which wind was predominantly blown from south
and south-west direction across the face of samplers.
This wind movement might influence the gravitational
settling and inertial impaction of wind blown particulates
at the time of deposition on samplers. In agreement with
the effect of wind movement on airborne pesticides,
Thistle (2000) asserted that the dispersion of pesticide
droplets in the air is influenced by the droplet size,
atmospheric stability and wind movement (vertical and
4016 Afr. J. Agric. Res.
Table 3. Glyphosate residue amount mean ± S.D measured on active air samplers before, during and after application in the treated
field air.
Spray periods
Active sampling
Air volume (m3)
Air concentration (µg/m
)
Quartz filter PUF plug Total air concentration
Pre- spray (4 h) 0.24 ND ND ND
During spray(25 min) 0.0075 42.8 ND 42.96 ± 7.96a
Post- spray 0-4 h 0.24 0.10 ND 0.10 ± 0.013b
4-8 h 0.24 0.051 ND 0.051 ± 0.007b
Samples that produced undetected results have been assigned as ‘ND’. Values followed by the same letter (s) column wise, are not
significantly different at (P < 0.05).
horizontal components).
Active air samplers
The air concentrations of glyphosate measured by active
sampling were presented in Table 3. The result showed
that glyphosate was not detected in any of the air
samples collected with polyurethane foam (PUF) plug
samples but it was detected only in quartz filter samples.
The absence of glyphosate in the PUF plug indicates that
glyphosate is not released as the vapour into the
atmosphere but rather is carried by particulate matter
(Humphries et al., 2005). In the pre-spray sampling event,
no glyphosate was detected in both quartz filter and PUF
plugs, this indicates that glyphosate is no longer in the
atmosphere in the wet and high humid morning but have
been removed through wet deposition.
The highest air concentrations of glyphosate (42.96
µg/m3) occurred during 25 min spray application period
that was collected through personal air sampling pump
operated at operator’s breathing zone. The result was
within a range of 0.41 to 48 µg/m3 glyphosate residue
levels in the working air depending upon the method of
application and rate of applications which was revealed in
a study conducted in Ukraine (Chmil and Kuznetsova,
2009). The high concentration measured during spray
application period was due to fine droplets produced by
mist blower sprayer that remain in the surrounding air
due to their lower terminal velocity (Matthews, 1999).
Most importantly, a significant proportion of these fine
droplets are inhalable particles that pose serious risk of
health injury to spray operators. On the post spray
sampling done by field air sampling pump, glyphosate
was detected in small amounts in quartz filter samples
that were drastically lower than the spray period
concentration. However, glyphosate concentrations were
markedly higher during 0 to 4 h post spray (0.10 µg/m3)
and decline during 4 to 8 h period (0.051 µg/m3).
However, this post spray results were far below the
reported residue range of 10 to 17 µg/m3 during 24 h post
spray fine filter sampling to measure Alberta’s
atmospheric glyphosate deposition conducted by Water
research group of Alberta Environment (Humphries et al.,
2005). Concentration of glyphosate in air was found very
small at post-spray sampling, and this occurrence might
be because of negligible volatility after spray application.
Furthermore, this might be due to the total volume of air
sampled with the field air sampling pump.
Paired comparison of passive sampling method
performance with active sampling
In field situations, there is a considerable variability of the
concentrations of airborne residues during sampling
periods in which the performance of both active and
passive sampling methods also showed different
performance in terms of residue uptake. Active air
samplers have been widely accepted as the reference
method for the evaluation of the performance of passive
air samplers. Hence, both active and passive samplings
were done side-by-side in all sampling events in this
study to do the paired comparison between the active
and passive sampling methods. This paired comparison
is important for the performance evaluation of passive
samplers by assessing the magnitude and direction of
differences between passive and active air samplers.
However, current National Institute for Occupational
Safety and Health (NIOSH), Health and Safety Executive
(HSE), and European Committee for Standardization
(CEN) validation protocols have used Student’s t-tests,
paired sample Student’s t-tests, and linear regression as
the statistical methods for evaluating the performance of
passive samplers. In this context, linear regression
analysis would be preferable providing a measure of the
degree of association between the two methods (that is,
the correlation of coefficient) on the assumption that a
linear relationship exists between them, over the range of
conditions covered by the field tests. Basically, these
tests can only investigate whether in general the mean
concentrations measured by active and passive sampling
Morshed et al. 4017
GLYPHOSATE
Residue concentration found by active sampling
(ppm)
Residue concentration found by passive
sampling (ppm)
Residue concentration found by active sampling (ppm)
Figure 4. Paired relationship between the active and passive sampling methods -based on the results of airborne
glyphosate residue uptake concentration (ppm).
methods are statistically different from each other, but not
identify the source of the differences (Shih et al., 2000).
The linear relation determined by the regression analysis
is taken the following equation form:
y = a + bx
Where y and x are the residue concentrations measured
by the passive and active sampling methods respectively.
For perfect agreement between the two methods, the true
values of the intercept (a) and slope (b) parameters
should be respectively 0 and 1.
From the field performances of three passive samplers
in terms of glyphosate residue uptake, it was quite
evident in this study that only cotton gauze samplers
showed residue uptake in comparison to other two
passive samplers. Therefore, passive (cotton gauze) and
active (quartz fibre filter) air samplers (a total of 6 pairs of
residue concentrations in ppm) were used for determining
the agreement between passive and active sampling
methods.
In regression analysis (Figure 4), linear correlation was
found between pair-wise (n = 6) comparison of residue
concentrations measured by active and passive sampling
methods over the range of 0.001 – 0.004 ppm. The linear
regression line equation showed satisfactory correlation
coefficient (R2 = 0.98) with a moderate slope (b = 1.63)
and a negative intercept (a = -0.0006). It was also
observed that residue concentration found at the second
post-spray events (4 to 8 h) were very close to standard
line (y = x line). In contrast, the residue concentrations
found during the first post-spray sampling events (0 to 4 h)
were far above the standard line. Hence, it can be
inferred that residue uptake by passive sampling was
much higher than active sampling method in the first
post-spray sampling event immediately after spraying,
and with passage of time the performance of two
methods became almost similar in the second sampling
event.
Conclusion
The study of airborne glyphosate residue in post-spray
application showed that in the air, glyphosate is
associated with particles rather than vapour. It was also
noted that meteorological conditions play a significant
role in atmospheric sampling. Among the three passive
samplers used in this study, only cotton gauze passive
sampler showed atmospheric glyphosate detection in
both post-spray sampling events and could be suitably
used for non-volatile pesticides residue measurement in
the air. In paired comparison between active and passive
sampling methods, it was quite evident that passive
sampling showed significantly better performance than
the active sampling. Although occupational safety
organizations have not yet established any threshold
limits for glyphosate exposure, but the air concentration
during spray application at sprayer’s breathing zone was
substantially higher that suggesting the use of personal
protective equipments (PPEs) for persons in charge of
application.
REFRENCES
Cox C (1995). Glyphosate, part 2: Human Exposure and Ecological
Effects. J. Pesticide Reform., 15(4): 14-20.
4018 Afr. J. Agric. Res.
CCM International (2009). Glyphosate Competitive Analysis in China.
http://www.researchandmarkets.com/reportinfo.asp?report_id=64903
1.
Chang FC, Simcik MF, Capel PD (2011). Occurrence and Fate of the
Herbicide Glyphosate and Its Degradate Aminomethylphosphonic
Acid in the Atmosphere. Environ. Toxic Chem., 30(3): 548-555.
Chmil V, Kuznetsova E (2009). Glyphosate: Environmental Fate and
Levels of Residues. Medved’s Institute of Ecohygiene and Toxicology,
Kiev, Ukraine.
http://www.cipac.org/NEXT_Meeting/.../Vitaly_Chmil_GLYPHOSATE.
pdf.
Duke SO, Powles SB (2008). Glyphosate-resistant Weeds and Crops.
Pest Manage. Sci., 64: 317-318.
Franz JE, Mao MK, Sikorski JA (1997). Glyphosate: A Unique Global
Herbicide. Am. Chem. Soc., 4: 65-97.
Gioia R, Offenberg JH, Gigliotti CL, Totten LA, Du SY, Eisenreich SJ
(2005). Atmospheric Concentrations and Deposition of
Organochlorine Pesticides in the US Mid-Atlantic Region. Atmos.
Environ., 39: 2309-2322.
Gorecki T, Namiesnik J (2002). ‘Passive Sampling’. Trends Anal. Chem.,
21: 276-291.
http://alcor.concordia.ca/~raojw/crd/reference/reference002139.html.
Humphries D, Byrtus G, Anderson AM (2005). Glyphosate Residues in
Alberta’s Atmospheric Deposition, Soils, and Surface Waters. Pub No.
T/806, Alberta Environment, Edmonton.
http://environment.gov.ab.ca/info/library/6444.pdf.
ICH (1996). Q2B Validation of Analytical Procedures: Methodology,
International Conference on Harmonization of Technical
Requirements for Registration of Pharmaceuticals for Human Use.
U.S.FDA. http://www.fda.gov/Regulatoryinformation/guidance.
Kot-Wasik A, Zabiegala B, Urbanowicz M, Dominiak E, Wasik A,
Namiesnik J (2007). Advances in Passive Sampling in Environmental
Studies (review article). Anal. Chim. Acta, 602: 141-163.
http://www.elsevier.com/locate/aca.
Matthews GA (1999). Application of Pesticides to Crops, Imperial
College Press, London, United Kingdom, pp. 1-311. ISBN: 1-86094-
168-0
Matthews GA (2000). ‘Spray Droplets’ In: Pesticide Application Methods.
Third Edition, Blackwell Science Limited, Oxford, United Kingdom.
ISBN: 0-632-05473-5
OECD (1997). Environmental Health and Safety Publications Series on
Testing and assessment No.9: Guidance document for the Conduct
of Studies of Occupational Exposure to Pesticides during Agricultural
Application. OCDE/GD(97)148y. OECD, Paris.
OSHA Method Number PV2067: Glyphosate, Occupational Safety and
health Administration, U.S. Department of Labor. Carcinogen and
Pesticide Branch, OSHA Analytical Laboratory, Salt Lake City, Utah.
http://www.osha.gov/dts/sltc/methods/partial/t-pv2067-01-8911-ch/t-
pv2067-01-8911-ch.html.
Seethapathy S, Gorecki T, Li X (2007). Passive sampling in
environmental analysis – A review. J. Chromatogr. A, 1184(1-2): 234-
235. doi:10.1016/j.chroma.2007.07.070.
Seiber JN, Ferreira GA, Hermann B, Woodrow JE (1980). Analysis of
pesticidal residues in the air near agricultural treatment sites, In:
harvey Jr. J, Zweig G (eds). Pesticide analytical methodology, ACS
Symposium Series, Washington D.C., 136: 177.
Shih TS, Chen CY, Cheng RI (2000). Field evaluation of a passive
sampler for the exposure assessment of 2-methoxyethanol. Int. Arch.
Occup. Environ. Health, 73: 98-104.
Tadeo JL (2008). Analysis of Pesticides in Food and Environmental
Samples, CRC press, Boca Raton, FL, p. 257.
Thistle H (2000). The role of stability in fine pesticide droplet dispersion
in the atmosphere: A review of physical concepts. Trans. ASAE, 46:
1409-1413.
UN-ECE (1979). Removal of Fine Particulates From The Atmosphere.
In: Particulate Pollution A report of the United Nations Economic
Commission for Europe. Pergamon Press ltd. Oxford, England, pp.
54-56. ISBN 0-08-023399-6.
USEPA (1993). EPA Reregistration Eligibility Document, Glyphosate.
EPA 738-R-93-014. Office of Prevention, Pesticides and Toxic
Substances, United States Environmental Protection Agency,
Washington, D.C.
Van Dijk HFG, Guicherit R (1999). Atmospheric dispersion of current-
use pesticides: A review of the evidence from monitoring studies.
Water, Air and Soil, 115: 21-70.
World Health Organization (WHO) (1994). Glyphosate. Environment
Health Criteria No. 159. World Health organization, Geneva,
Switzerland.http://www.inchem.org/documents/ehc/ehc159.htm.
Woodrow JE, Hebert V, LeNoir JS (2003). ‘Monitoring of agrochemical
residues in air’ In: ‘Handbook of Residue Analytical Methods for
Agrochemicals’ ed. Philip W. Lee, 1: 908-935. John Wiley & Sons Ltd.
USA. ISBN: 0-471- 49194-2.
... Exposure generally occurs through the skin, but inhalation and indirect ingestion can occur as well. Several researchers have studied breathing zone air exposure of glyphosate during spraying (Jauhiainen et al. 1991;Lavy et al. 1992;Johnson et al. 2005;Morshed et al. 2011). Some studies have investigated glyphosate biomonitoring exposure of agricultural family members (Acquavella et al. 2004;Curwin et al. 2005;Mesnage et al. 2012). ...
... The higher percent of relative humidity was significantly resulted in higher inhalation exposure of glyphosate among the farmers which was similar to the review of Damalas and Eleftherohorinos (2011) said that the low relative humidity and high temperature would cause rapid evaporation of spray droplets resulted in lower exposure of sprayer. Morshed et al. (2011) collected breathing zone air samples of glyphosate for 12 h using motorized knapsack sprayers in Malaysia (Morshed et al. 2011). Air sampling was conducted in 12 h, 4 h prespray, 25 min spraying, and postspray periods (0-4 and 4-8 h). ...
... The higher percent of relative humidity was significantly resulted in higher inhalation exposure of glyphosate among the farmers which was similar to the review of Damalas and Eleftherohorinos (2011) said that the low relative humidity and high temperature would cause rapid evaporation of spray droplets resulted in lower exposure of sprayer. Morshed et al. (2011) collected breathing zone air samples of glyphosate for 12 h using motorized knapsack sprayers in Malaysia (Morshed et al. 2011). Air sampling was conducted in 12 h, 4 h prespray, 25 min spraying, and postspray periods (0-4 and 4-8 h). ...
Article
In Thailand, glyphosate is popular herbicide to control pests in the agricultural sector. This study aimed to measure glyphosate exposure concentrations through inhalation, dermal contact, and urinary glyphosate concentrations among 43 vegetable farmers spraying glyphosate in Bungphra Subdistrict, Phitsanulok Province. Four types of spraying equipment were used, manual pump backpack (n = 3), motorized spray backpack (n = 22), battery pump backpack (n = 16), and high pressure pump (n = 2). Breathing zone air samples were collected using glass fiber filters; dermal contact samples were collected using 100 cm² cotton patches attached on 10 body locations and urine samples were collected at 3 time points: morning void urine the day before spraying, the end of spraying event, and the morning void urine the next day of spraying. The results showed that the geometric mean (GM; geometric standard deviation [GSD]) of breathing zone concentrations of glyphosate exposure were 9.37 (10.17) µg/m³. The GM (GSD) of total dermal patches exposure concentrations were 7.57 (0.01) mg/h. The legs, back, and arms were the most exposed body areas. The GM (GSD) of urinary glyphosate was found highest among vegetable farmers using manual backpack 46.90 (1.35) µg/g creatinine. Farmers should wear masks and boots to reduce glyphosate exposure by inhalation and dermal contact.
... Morshed und Mitautoren kommen aufgrund ihrer Ergebnisse aus einem Experiment mit Passivund Aktivsammlern (s. Glossar) in Malaysia zu dem Schluss, dass bei Glyphosat der Transport über Bodenpartikel wahrscheinlich ist (Morshed, Omar et al. 2011). Bei Messungen vor und nach der Applikation von Glyphosat konnte das Herbizid hauptsächlich in der Glasfiber-Matrix des Aktivsammlers nachgewiesen werden. ...
... Allerdings gab es keine Daten über die Empfindlichkeit gegenüber Glyphosat. Mahbub Morshed konnte in einem Experiment mit kontrollierter Glyphosat-Applikation kein Glyphosat in der sonst so effektiven PUF-Matrix nachweisen (Morshed, Omar et al. 2011). ...
... Glossar) der Langzeit-Messung aus dem GAPS-Programm mit einer kontrollierten Glyphosat-Ausbringung (Hofmann, Schlechtriemen et al. 2019b). Im Gegensatz zu Mahbub Morshed (Morshed, Omar et al. 2011) konnten Hofmann und Schlechtriemen (Hofmann, Schlechtriemen et al. 2019b) ...
Article
Full-text available
Pesticide contamination in ambient air A Germany-wide study to determine the occurrence of pesticides in ambient air, honeybee bread, filters from ventilation systems and air quality bark monitoring were analysed for the presence of over 500 pesticides and their related active substances including glyphosate. Dr. Maren Kruse-Plaß Dr. Werner Wosniok Dipl.-Forstwirt Ulrich Schlechtriemen – all TIEM integrierte Umweltüberwachung Abstract For the Federal Republic of Germany, the present study is the most comprehensive collection of data on the occurrence and distribution of pesticides in the air. The results show that the existence of uncontaminated sites within a year of measuring is very unlikely. The number and composition of the pesticides found as well as the level of exposure depend on the sampling site, the sampling media and on the characteristics of the pesticides. The contamination tends to be higher in areas where an intensive use of pesticides can be assumed. The distance to the next potential source had little impact. Even in areas where pesticides are not applied one can expect to find a cocktail of pesticides in the air. The effect of these airborne substances on humans is still unknown. The results gathered through non-biological collection media indicate that in the air, glyphosate is more widespread than any of the other active substances studied. It is the first time that the presence of this pesticide in ambient air has been documented to this extent. Tree bark measurements taken between 2014 and 2018 provided a first indication that pesticides used in conventional agriculture can be widely distributed through the air (Hofmann, Schlechtriemen et al. 2019). The purpose of this study was to expand on these results by using a number of additional methods to measure the pesticide contamination in the air. For this purpose, in 2019, 116 sites across the Federal Republic of Germany were examined as part of a Citizen Science project. The following collection methods were employed: technical passive samplers (49 samples), filter mats from ventilation systems (20 samples), honeybee bread (41 samples) and tree bark samples (6 samples). The samples were analysed by using multi-analysis for over 500 pesticide active substances including glyphosate, glufosinate and AMPA (aminomethylphosphonic acid, degradation product of glyphosate). The results were compared with data from earlier bark analyses from the years 2014 to 2018 (47 samples). • In 163 samples, a total of 152 active substances were detected, • 138 were attributable to agricultural sources. • Out of these, 41 active substances (30 percent) are no longer licensed for use in the Federal Republic of Germany. Results of different collection methods In general, passive samplers provided the most meaningful results. A total of 80 active substances were detected. The results are based on the government guideline for the detection of pesticide residues in food stuff (ASU L 00.00 – 115, compiled by the BVL (Bundesamt für Verbraucherschutz und Lebensmittelsicherheit; BVL 2018). In a second step these detected active substances were reduced to contain only agents with a primarily agricultural origin. After excluding PCB (5) and other substances of non-agricultural origin (4) from the original list 71 active substances remain. After active substance reduction 5 to 31 pesticides active substances were detected per sampling site. The median number of active substances in the passive samplers is 17. In this study, the active substances most commonly found include glyphosate, chlorothalonil, metolachlor, pendimethalin, terbuthylazine, prothioconazole-desthio (degradation product of prothioconazole), dimethenamide, prosulfocarb, AMPA, flufenacet, tebuconazole, aclonifene, chlorflurenol, HCH-gamma (lindane), MCPA (2-methyl-4-chlorphenoxyacetic acid), epoxiconazole and folpet. The active substances listed were detected at least on one third (16 locations) of the 49 passive sampling sites. Glyphosate was detected in all samples of non-biological origin (100 percent of all sites with passive samplers and filter mats). The lowest contamination was found in the Bavarian Forest National Park (sample no. 747/1007). Here, in addition to glyphosate, 4 other active substances from pesticides were identified. In addition to the ubiquitous substance lindane, there are pesticides detected which are currently in use: dimethenamide, chlorothalonil and chlorpropham (in Germany the approval for both substances was withdrawn in 2019, their grace period ends in 2020 (BVL 2019a, BVL 2019b)). A site in eastern Germany (sample no. 723/869) in a wine-growing region recorded the highest number of detected active substances (31). High levels of contamination are also found in other fruit and wine growing areas (sample no. 736/948 (28)). A larger number of active substances per test site was found in northern Germany (sample no. 746/778 (29), sample no. 726/879 (27), sample no 742/1002 (26)), but also in eastern Germany (sample no. 703/709 (26)). A high number of detected pesticides per test site is not linked to high on-site pesticide application. Sites P-No. 742/1002 and 744/1004 are among the most contaminated sites with 26 and 24 pesticides detected, respectively. Both sampling sites were located on large organically managed farms. With 3916 ng/sample, the highest value for pendimethalin was measured at site 744/1004. Previously, organic produce from the area had been found to exceed the threshold for pesticide contamination. The Harz National Park (Brockengarten, sample no. 740/1000) is a particularly striking example for pesticide contamination in northern Germany: 12 pesticide active substances were found, several in highly significant quantities, e.g. glyphosate (99.2 ng/sample), chlorothalonil (1494.7 ng/sample), terbuthylazine (49.3 ng/sample), prothioconazole-desthio (58.7 ng/sample). Folpet, a pesticide used in wine growing, was also measured with 23.5 ng/sample (for all measures see table 32 in the main report). While the PUF matrix in passive samplers absorbs volatile pesticide active substances, filter mats in ventilation systems are designed to filter dust particles from the air. It can therefore be assumed that the detected pesticides initially adhered to soil particles which, transported by wind, were caught in the filter of the ventilation system. This may cause them to accumulate in the collection medium. In 20 samples 62 pesticide active substances with a primarily agricultural origin were detected. Sites were contaminated with between one and 34 active substances. For bees the collection spectrum is different again. Unlike passive samplers and filter mats, bee bread reflects the bees’ exposure to insecticides such as thiacloprid. In 41 samples, 48 pesticide active substances were found, with 0 to 12 active substances per site. The samples from tree bark monitoring show the widest range of pesticide active substances. In 53 samples 94 active substances were found in total and at each site 1 to 26 pesticides were present. The statistical analysis The statistical analysis examines six locational factors for their effect on the measured values. It identifies the natural area of the site and the intensity of agriculture as important influencing factors in the passive samplers. The distance to the nearest potential source and the location in a nature reserve has little impact on the values detected. Also, the orientation of a site towards organic management, wind erosion classification of the underlying soil and the biogeographical area have no effect on the number of observed active substances. Only for metolachlor significantly lower values can be found in organic farming. The data are complexly linked and must be considered separately for each active substance investigated. The composition of the active substances detected varies for the different media tested. References BVL, Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (2019a). Widerruf der Zulassung von Pflanzenschutzmitteln mit dem Wirkstoff Chlorothalonil zum 31. Oktober 2019. Vom 19.06.2019. "Fachmeldungen aus dem Arbeitsbereich "Pflanzenschutzmittel". Retrieved 21.04.2020, from https://www.bvl.bund.de/SharedDocs/Fachmeldungen/04_pflanzenschutzmittel/2019/2019_06_19_Fa_Widerruf_Chlorothalonil.html BVL, Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (2019b). Vom 21.06.2019. "Fachmeldungen aus dem Arbeitsbereich "Pflanzenschutzmittel". Retrieved 21.04.2020, from https://www.bvl.bund.de/SharedDocs/Fachmeldungen/04_pflanzenschutzmittel/2019/2019_06_21_Fa_Nichtgenehmigung_Chlorpropham.html BVL, Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (2018): Untersuchung von Lebensmitteln - Multiverfahren zur Bestimmung von Pestizidrückständen mit GC-MS und LCMS/MS nach Acetonitril-Extraktion/Verteilung und Reinigung mit dispersiver SPE in pflanzlichen Lebensmitteln - Modulares QuEChERS-Verfahren. (Neufassung der Methode L 00.00-115 durch die Arbeitsgruppe „Pestizide“ nach § 64 LFGB). Beuth Verlag. Hofmann, F., U. Schlechtriemen, M. Kruse-Plaß and W. Wosniok (2019). Biomonitoring der Pestizid-Belastung der Luft mittels Luftgüte-Rindenmonitoring und Multi-Analytik auf >500 PSM-Wirkstoffe sowie Glyphosat. Dortmund: TIEM Integrierte Umweltüberwachung. http://enkeltauglich.bio/wp-content/uploads/2019/02/Bericht-H18-Rinde-20190210-1518-1.pdf
... In It had been concluded that the existence of glyphosate in air is due to spray drift or wind erosion as it is not a volatile compound whereas AMPA presence is due to wind erosion as it is a glyphosate degradation product and it is formed in soil [128]. The authors provided also measurements in rainwater and estimated that 97% of glyphosate existing in the atmosphere could be removed by weekly rainfall greater than 30 mm [129]. ...
... Morshed et al. determined the atmospheric concentrations of glyphosate in treated fields in Malaysia during spray applications by a mist blower [129]. The maximum concentration of 42.96 μgm −3 was measured for glyphosate, and additionally a first modeling attempt for the estimation of glyphosate emission to the atmosphere at regional level was done; however, there were no measurements to confirm the model output. ...
... Cellulose filter patches and polyurethane foam were used for passive samplers. Active samplers were also used for sampling and were connected to polyurethane foam plug for the determination of glyphosate existing in the vapor phase and a quartz fiber filter for the particulate phase of airborne glyphosate [129]. Sample extraction for both active and passive extraction methods was performed with borate buffer. ...
Chapter
Full-text available
Glyphosate [N-(phosphonomethyl) glycine] (GPS) is currently the most commonly applied herbicide worldwide. Given the widespread use of glyphosate, the investigation of the relationship between glyphosate and soil ecosystem is critical and has great significance for its valid application and environmental safety evaluation. However, although the occurrence of glyphosate residues in surface and groundwater is rather well documented, only few information are available for soils and even fewer for air. Due to this, the importance of developing methods that are effective and fast to determine and quantify glyphosate and its major degradation product, aminomethylphosphonic acid (AMPA), is emphasized. Based on its structure, the determination of this pesticide using a simple analytical method remains a challenge, a fact known as the “glyphosate paradox.” In this chapter a critical review of the existing literature and data comparison studies regarding the occurrence and the development of analytical methods for the determination of pesticide glyphosate in soil and air is performed.
... 1,2 Several methods have been described to monitor personal exposure to glyphosate in workplace air. [5][6][7] However, the sampling capacity and sensitivity of these methods did not meet the specified criteria of MHLW guidelines. 8 We aimed to develop and validate a monitoring method for personal exposure to glyphosate for quantitative risk assessments. ...
... Although this concentration range corresponds from 1/6000 to 1/3 times the OEL proposed by the JSOH, this covers glyphosate concentrations (0.63-43 μg/m 3 ) reported in previous studies. [5][6][7] If the glyphosate concentration exceeds the calibration range, the extracted sample solution should be reanalyzed after an appropriate dilution. Through sampling and analysis, relative standard deviations (RSD) relating to the overall reproducibility of the proposed method were determined to be from 1.4% to 1.8% (Table 1). ...
Article
Full-text available
Objectives: We aimed to develop a method to determine workers' personal exposure levels to N-(phosphonomethyl)glycine (glyphosate) for their risk assessments. Methods: The proposed method was assessed as follows: recovery, stability of samples on storage, method limit of quantification, and reproducibility. Glyphosate in air was sampled using an air-sampling cassette containing a glass fiber filter. Ultrapure water was used to extract glyphosate from sampler filters. After derivation with 9-fluorenylmethyloxycarbonyl chloride, samples were analyzed by high-performance liquid chromatography using a fluorescence detector. Results: Spiked samples indicated an overall recovery of 101%. After 7 days of storage at 4°C, recoveries were approximately 100%. The method limit of quantification was 0.060 μg/sample. Relative standard deviations representing overall reproducibility, defined as precision, were 1.4%-1.8%. Conclusions: The method developed in this study allows 4-h personal exposure monitoring of glyphosate at 0.250-500 μg/m3 . Thus, this method can be used to estimate worker exposure to glyphosate.
... However, when considering occupational hazard, glyphosate exposure through contaminated atmosphere may present higher concerns. Morshed et al. (2011) evaluated glyphosate's concentration in the atmosphere before, during and after herbicide application [57]. While no glyphosate was detected prior to its application, in the following periods its concentration in air increased to 0.1 µg/mL (0-4 h after application) and to 0.05 µg/mL (4-8 h after application). ...
... While no glyphosate was detected prior to its application, in the following periods its concentration in air increased to 0.1 µg/mL (0-4 h after application) and to 0.05 µg/mL (4-8 h after application). With greater interest toward human exposure, during the application, glyphosate's atmospheric concentration was~43 µg/mL [57], and therefore significantly higher than the remaining values reported, which highlights the occupational hazards for workers. ...
Article
Full-text available
Glyphosate-based herbicide has been the first choice for weed management worldwide since the 1970s, mainly due to its efficacy and reported low toxicity, which contributed to its high acceptance. Many of the recent studies focus solely on the persistence of pesticides in soils, air, water or food products, or even on the degree of exposure of animals, since their potential hazards to human health have raised concerns. Given the unaware exposure of the general population to pesticides, and the absence of a significant number of studies on occupational hazards, new glyphosate-induced toxicity data obtained for both residual and acute doses should be analyzed and systematized. Additionally, recent studies also highlight the persistence and toxicity of both glyphosate metabolites and surfactants present in herbicide formulations. To renew or ban the use of glyphosate, recently published studies must be taken into account, aiming to define new levels of safety for exposure to herbicide, its metabolites, and the toxic excipients of its formulations. This review aims to provide an overview of recent publications (2010–present) on in vitro and in vivo studies aimed at verifying the animal toxicity induced by glyphosate, its metabolite aminomethylphosphonic acid (AMPA) and glyphosate-based formulations, evaluated in various experimental models. Apart from glyphosate-induced toxicity, recent data concerning the role of surfactants in the toxicity of glyphosate-based formulations are discussed.
... HPLC analyses were performed according to the analytical methodology developed by Morshed et al. (2011), using Varian ProStar HPLC with diode arrangement detector (DAD/HPLC), μBondapak™ C18 column (10 μm, 3.9 mm × 300 mm), wavelength of 195 nm, injection volume of 20 μL, mobile phase of 0.006 mM KH 2 PO 4 , and flow rate of 1.0 mL/min. Retention time was 2.97 min for an analytical run of 7 min. ...
... Jauhiainen et al. (1991) reported levels of up to 15 μg/m 3 glyphosate in the air during spray periods. Morshed et al. (2011) studied the presence of glyphosate residues in the Malaysian atmosphere under tropical climate conditions with high temperatures in air samples collected in the pre-spraying and post-spraying of an agricultural area in the 12-h period. The authors report that during 25 min of spraying, a high glyphosate concentration of 42.96 μg/m 3 was detected in the samplings carried out in the operator's breathing area, which was considered to be very high. ...
Article
Full-text available
The municipality of Limoeiro do Norte-Ceará, located in northeastern Brazil, stands out as a major center of agribusiness due to the high productivity indexes, especially in the irrigated fruit production, with a high consumption of pesticides, including glyphosate, considered potentially carcinogenic by International Agency for Research on Cancer (IARC). In this context, the aim of this study is to evaluate the atmospheric pollution caused by the use of glyphosate herbicide in the rural and urban zones of the municipality of Limoeiro do Norte, evaluating the impacts on the environment and health of the population. Samplings were performed over a period of 4 months using calibrated air samplers. Concentrations of TSP and glyphosate were estimated by gravimetric and liquid chromatography methods, respectively. The results showed TSP levels between 10.8 and 137.4 μg/m³ (mean of 41.1 μg/m³) in rural zone and between 3.87 and 97.7 μg/m³ (average of 38.1 μg/m³) in the urban zone. The glyphosate associated with TSP in the rural zone presented levels between 0.002 and 0.144 μg/m³ (mean of 0.055 μg/m³) and the atmospheric TSP (gas phase) showed levels between 0.313 and 2.939 μg/m³ (average of 1.218 μg/m³). The glyphosate associated with TSP in the urban zone ranged from 0.009 to 2.576 μg/m³ (mean of 1.006 μg/m³). These values can be considered high and dangerous to human health and to the environment.
... Authors estimated that 97% of Glyphosate in the air would be removed by weekly rainfall greater than 30 mm. More, a study was carried out in Malaysia to determine Glyphosate atmospheric concentrations in a treated field (Morshed et al., 2011). They reached 42.96 μg m −3 during spraying using a calibrated mist blower. ...
... These maximum values were much smaller than those measured in US agricultural areas where they can reach 9.1 ng m −3 in Mississippi (2007( , Chang et al., 2011 during the application period. However, these concentrations should be compared with the highest concentration (i.e., 42.96 μg m −3 ) measured in the atmosphere near a spray application (Morshed et al., 2011). In 2015, 2016, among herbicides searched on the sampling sites under study, only Pendimethalin was quantified at a higher concentration, i.e., 1.924 ng m −3 in Cavaillon. ...
Article
Glyphosate, AMPA, its main metabolite, and Glufosinate-ammonium were monitored in ambient air samples collected for two years (2015–2016), at four sampling sites in Provence-Alpes-Côte-d'Azur Region (PACA, France) in different areas typologies (non-agricultural areas: city center, ‘zero pesticide’ policy, and industrial area but also agricultural sectors: mainly orchards and vineyards). Neither Glufosinate-ammonium nor AMPA were detected. Glyphosate was detected at a global frequency of 7% with frequencies ranging from 0% (Nice) to 23% (Cavaillon), according to the sampling site. Glyphosate concentration reached a maximum level of 1.04 ng m ⁻³ in the rural site of Cavaillon. This is despite the physicochemical characteristics of Glyphosate which are not favorable to its passage into the atmosphere. The absence of simultaneous detection of Glyphosate and AMPA suggests that drift during spraying operation is the main atmospheric source of Glyphosate and that resuspension from soil particles is minor. The present study offers one of the few report of Glyphosate, Glufosinate-ammonium, and AMPA in the air.
... However, no data were available on the efficacy of these passive air samplers in measuring glyphosate. Morshed et al. were unable to detect glyphosate in the otherwise effective PUF disk [22]. In a prior experiment [23], TIEM Environmental Monitoring established the PEF (diameter: 8 cm; height: 2 cm, with a round Sect. 3 cm in diameter in the middle; obtained from Freudenberg Filtration Technologies, Weinheim, Germany) as the most effective collection medium. ...
Article
Full-text available
Background Tree bark measurements conducted between 2014 and 2017 in a biosphere reserve in Germany have indicated the presence of pesticides from conventional agriculture in ambient air. In the present study, we quantified pesticides and related substances in ambient air at 69 sites using passive air samplers and ventilation filter mats. It is, to our knowledge, so far the most comprehensive data set on pesticides and their related products in ambient air in Germany. Results Samples were collected in 2019 and analysed for over 500 substances. One hundred and nine (109) were detected, including 28 that are not approved for use in Germany. In each sampling site, we identified one to 36 substances, including locations such as national parks and forests. Here, the presence of pesticides is not expected, e.g., on the highest mountain top in the national park “Harz” (13 substances) and in the "Bavarian Forest" (six substances). Glyphosate was recorded in every sample. More than half of passive air samplers contained chlorothalonil, metolachlor, pendimethalin, terbuthylazine, prothioconazole-desthio, dimethenamid, prosulfocarb, flufenacet, tebuconazole, aclonifen, chlorflurenol, hexachlorobenzene (HCB), and γ-hexachlorocyclohexane (γ-HCH). Filter mats also contained boscalid. The statistical analysis showed that landscape classification and agricultural intensity were the primary factors influencing the number of substances detected in ambient air. Location, such as protected areas or regions of organic farming, had only a small effect on the number of substances recorded. Medium- and long-range transport likely accounts for these findings. Extending the current sampling method will probably detect more pesticides than the data currently suggest. Conclusions Airborne pesticide mixtures are ubiquitous in Germany, which is particularly concerning for glyphosate, pendimethalin, and prosulfocarb. Deposition of these pesticides on organic products may disqualify them from the market, resulting in economic losses to farmers. Air concentrations of pesticides are a relevant issue and must be reduced.
... In France, detected glyphosate reached a peak of 9.5 µg/L in the urine samples of farmers who sprayed glyphosate 7 . The highest concentration of atmospheric glyphosate (42.96 µg/m 3 ) was measured in the air of the operator's breathing zone 8 . Therefore, workers exposed to glyphosate though the inhalation route excreted glyphosate in the urine. ...
Article
Full-text available
Context: Herbicide poisoning has been increasing among agriculturists in the northeast of Thailand. The aim of this cross-sectional study was to assess the health risk of glyphosate exposure among knapsack sprayers. A health risk assessment matrix was applied to 243 sprayers by considering the extent of glyphosate exposure per year according to the actual amount of glyphosate (48 %w/v) dispensed and frequency of exposure. In addition, use of personal protective equipment (PPE) was taken into account. The second component of the risk matrix was the severity of the recorded adverse effects in the same group. The results revealed that 76.95% of sprayers were slightly exposed (100 to 499 milliliters of glyphosate used per year) and 57.20% wore at least four types of protection, comprised from any of the following types: gloves, mask, boots, trousers, long-sleeved shirt, and others. A majority had a slight likelihood of glyphosate exposure (69.14%) and a minority experienced a mild level of adverse symptoms (17.28%), including rash, dizziness and headache. Some sprayers (36.20%) had a health risk of glyphosate exposure higher than an acceptable level, which might explain the adverse health effects of long-term exposure. This health risk assessment tool combined with PPE usage of a herbicide applicator would be useful for the health surveillance program.
Article
North-Eastern Italy and in particular Veneto Region, stands out as a major centre of agriculture and viticulture which has rapidly expanded in the last decade with high productivity indexes. In this context, assessing atmospheric pollution caused by crop spraying with pesticides in rural areas and their transport to high-altitude remote sites is crucial to provide a basis for understanding possible impacts on the environment and population health. We aim to improve existing methods with a highly sensitive technique by using high pressure anion exchange chromatography coupled to a triple quadrupole mass spectrometer. Thus, a total of fourteen polar pesticides were determined in aerosol samples collected from August to December 2021 at Roncade (Venetian plain) and Col Margherita Observatory (Dolomites). The observatory was chosen as the background site as it is representative of the surrounding alpine region. Some samples revealed a substantial amount of cyanuric acid mainly at Roncade (mean concentration of 10 ± 10 ng m⁻³), glyphosate and fosetyl-aluminium (0.1 ± 0.2 and 0.1 ± 0.1 ng m⁻³, respectively). Surprisingly, some pesticides have been also found at Col Margherita, a high mountain background site, with concentrations an order of magnitude lower than at Roncade. This is the first time that fourteen polar pesticides have been assessed in the aerosol phase of the Po’ Valley and detected at a high-altitude remote site, and consequently this study provides the first data on their occurrences in Italian aerosols. It represents a basis for the assessment of risks for humans.
Article
Full-text available
Passive sampling is based on free flow of analyte molecules from the sampled medium to a collecting medium as a result of a difference in chemical potentials. It can be used for the determination of both inorganic and organic compounds in a variety of matrices, including air, water and soil. The devices used for passive sampling are usually based on diffusion through a well-defined diffusion barrier or permeation through a membrane. Living organisms can also be used as passive samplers. In most cases, passive sampling vastly simplifies sampling and sample preparation, eliminates power requirements, and significantly reduces the costs of analysis. The technique is particularly suited to the determination of time-weighted average concentrations.
Book
Developing safety regulations for pesticides used around the world-in excess of 2.5 million tons annually-requires reliable analytical methods for assessing their impact in food and in the environment. Analysis of Pesticides in Food and Environmental Samples presents the most effective techniques for analyzing pesticide residues and other chemical contaminants in foods as well as in soil, water, and air. Renowned Scientists Report New Data and Advances in the Field The book introduces sample preparation, extraction, and analytical methods specific to each sample type, including foods from vegetal and animal origin. Other chapters discuss important aspects of quality assurance and the applicability of hyphenated analytical techniques. In addition to a practical chapter on the use of biosensors and immunoassays for monitoring and gathering exposure data, the book addresses regulatory aspects and presents current data on the levels of pesticides found in food and environmental matrices. Latest Methods Help Scientists Develop Safer, More Effective Pesticides Analysis of Pesticides in Food and Environmental Samples enables scientists to measure and predict the behavior and toxicity of pesticides with a higher degree of accuracy. The methodologies and insight in this timely work will contribute to the development of more effective, less toxic pesticides as well as better safety regulations.
Book
Describes application methods on various types of crops.
Article
Substantial quantities of pesticides become airborne during and following spraying operations. This loss route has economic implications; at the least, airborne material leaves the intended use area and is no longer efficacious and, if the chemical is phytotoxic, drift damage to non-target foliage may result. Furthermore, airborne residues present a potential exposure route for farm workers and other individuals dwelling near agricultural sites, and atmospheric transport may be a major pathway for widespread distribution of pesticides--particularly the more persistent ones--in the environment. Evidence to support these contentions comes from several sources: (1) Assessment of drift during spraying (1, 2, 3). These studies typically employ fallout collectors, particulate air samplers, and, sometimes, sensitive plants or animals placed at distances from a spraying operation (4). The emphasis has been on particulates--their nature, concentration, and size--in relation to spray variables and meteorological conditions. (2) Assessment of evaporative losses following application (5, 6).
Article
The investigation of the role of atmospheric stability in the atmospheric dispersion of pesticide sprays and powders has largely been approached from an empirical standpoint. This article discusses the physical basis underlying the observed results relying on work done by boundary layer meteorologists and air pollution engineers. An examination of the turbulence equation, atmospheric turbulence spectra, and simple applied modeling techniques based on accumulated data all lead to the conclusion that atmospheric stability will influence droplet dispersion through reduced mixing as the atmosphere becomes more stable. The magnitude and interaction of stability with spray application parameters requires further study.
Article
Organochlorine pesticides (OCPs) were measured in the atmosphere over the period January 2000–May 2001 at six locations as part of New Jersey Atmospheric Deposition Network (NJADN). Gas phase, particle phase and precipitation concentrations of 22 OCP species, including chlordanes, DDTs, HCHs, endosulfan I and II, aldrin and diedrin, were measured. OCPs are found predominantly in the gas phase in all seasons, representing over 95% of the total air concentrations. Most of the pesticides measured display highest concentrations at urban sites (Camden and New Brunswick), although in many cases the differences in geometric mean concentrations are not statistically significant. The relationship of gas-phase partial pressure with temperature was examined using the Clausius–Clapeyron equation; significant temperature dependencies were found for all OCPs, except aldrin. Atmospheric depositional fluxes (gas absorption into water+dry particle deposition+wet deposition) to the New York–New Jersey Harbor Estuary of selected OCPs were estimated at NJADN sites. Atmospheric concentrations of dieldrin, aldrin and the HCHs are similar to those measured by the Integrated Atmospheric Deposition Network (IADN) in the Great Lake Region. In contrast, concentrations of DDTs, chlordanes and heptachlor are higher in the Mid-Atlantic compared to the Great Lakes, suggesting that the New York–New Jersey Harbor Estuary receives higher fluxes of these chemicals than the Great Lakes.
Article
Recently, evidence has accumulated that the extensive use of modern pesticides results in their presence in the atmosphere at many places throughout the world. In Europe over 80 current-use pesticides have been detected in rain and 30 in air. Similar observations have been made in North America. The compounds most often looked for and detected are the organochlorine insecticide lindane and triazine herbicides, especially atrazine. However, acetanilide and phenoxyacid herbicides, as well as organophosphorus insecticides have also frequently been found in rain and air. Concentrations in air normally range from a few pg/m3 to many ng/m3. Concentrations in rain generally range from a few ng/L to several µg/L. In fog even higher concentrations are observed. Deposition varies between a few mg/ha/y and more than 1 g/ha/y per compound. However, these estimates are usually based on the collection and analysis of (bulk) precipitation and do not include dry particle deposition and gas exchange. Nevertheless, model calculations, analysis of plant tissue, and first attempts to measure dry deposition in a more representative way, all indicate that total atmospheric deposition probably does not normally exceed a few g/ha/y. So far, little attention has been paid to the presence of transformation products of modern pesticides in the atmosphere, with the exception of those of triazine herbicides, which have been looked for and found frequently. Generally, current-use pesticides are only detected at elevated concentrations in air and rain during the application season. The less volatile and more persistent ones, such as lindane, but to some extent also triazines, are present in the atmosphere in low concentrations throughout the year. In agricultural areas, the presence of modern pesticides in the atmosphere can be explained by the crops grown and pesticides used on them. They are also found in the air and rain in areas where they are not used, sometimes even in remote places, just like their organochlorine predecessors. Concentrations and levels are generally much lower there. These data suggest that current-use pesticides can be transported through the atmosphere over distances of tens to hundreds, and sometimes even more than a thousand kilometres. The relative importance of these atmospheric inputs varies greatly. For mountainous areas and remote lakes and seas, the atmosphere may constitute the sole route of contamination by pesticides. In coastal waters, on the other hand, riverine inputs may prevail. To date, little is known about the ecological significance of these aerial inputs.
Article
Passive sampling is based on the phenomenon of mass transport due to the difference between chemical potentials of analytes in a given environmental compartment and the collection medium inside a dosimeter. The subsequent laboratory procedure (i.e. extraction, identification and determination of analytes) is the same as in the case of classic sampling techniques.Passive sampling techniques are characterized by simplicity with regard to the dosimeter's construction as well as its maintenance. Therefore, they find ever increasing application in the field of environmental research and analytics. When choosing a passive sampling method, one should not forget that some passive samplers require the time-consuming calibration step before being used in the field.Novel solutions and modifications of existing sampler designs have been presented. Practical application of passive dosimetry in environmental analytics, including sampling of water, soil, air and other atypical media are discussed. Some aspects of calibration methods in passive dosimetry are also described. The latest trends in the application of passive sampling are highlighted.
Article
This is the first report on the ambient levels of glyphosate, the most widely used herbicide in the United States, and its major degradation product, aminomethylphosphonic acid (AMPA), in air and rain. Concurrent, weekly integrated air particle and rain samples were collected during two growing seasons in agricultural areas in Mississippi and Iowa. Rain was also collected in Indiana in a preliminary phase of the study. The frequency of glyphosate detection ranged from 60 to 100% in both air and rain. The concentrations of glyphosate ranged from <0.01 to 9.1 ng/m(3) and from <0.1 to 2.5 µg/L in air and rain samples, respectively. The frequency of detection and median and maximum concentrations of glyphosate in air were similar or greater to those of the other high-use herbicides observed in the Mississippi River basin, whereas its concentration in rain was greater than the other herbicides. It is not known what percentage of the applied glyphosate is introduced into the air, but it was estimated that up to 0.7% of application is removed from the air in rainfall. Glyphosate is efficiently removed from the air; it is estimated that an average of 97% of the glyphosate in the air is removed by a weekly rainfall ≥ 30 mm.