CEN/TS 16817-1:2015

SLOVENSKI STANDARD
01-februar-2016
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Ambient air - Monitoring the effects of genetically modified organisms (GMO) - Pollen
monitoring - Part 1: Technical pollen sampling using pollen mass filter (PMF) and Sigma-
2-sampler
Außenluft - Monitoring der Wirkungen gentechnisch veränderter Organismen (GVO) -
Pollenmonitoring - Teil 1: Technische Pollensammlung mit Pollenmassenfilter (PMF) und
Sigma-2-Sammler
Air ambiant - Surveillance des effets d'organismes génétiquement modifiés (OGM) -
Surveillance du pollen - Partie 1 : Échantillonnage technique du pollen à l'aide d'un filtre
de masse à pollen (FMP) et d'un échantillonneur Sigma-2
Ta slovenski standard je istoveten z: CEN/TS 16817-1:2015
ICS:
13.040.20 Kakovost okoljskega zraka Ambient atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TS 16817-1
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
October 2015
TECHNISCHE SPEZIFIKATION
ICS 07.080; 13.020.99
English Version
Ambient air - Monitoring the effects of genetically
modified organisms (GMO) - Pollen monitoring - Part 1:
Technical pollen sampling using pollen mass filter (PMF)
and Sigma-2-sampler
Air ambiant - Surveillance des effets d'organismes Außenluft - Monitoring der Wirkungen von
génétiquement modifiés (OGM) - Surveillance du gentechnisch veränderten Organismen (GVO) -
pollen - Partie 1 : Échantillonnage technique du pollen Pollenmonitoring - Teil 1: Technische Pollensammlung
à l'aide d'un filtre de masse à pollen (PMF) et d'un mit Pollenmassenfilter (PMF) und Sigma-2-Sammler
échantillonneur Sigma-2
This Technical Specification (CEN/TS) was approved by CEN on 16 May 2015 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 16817-1:2015 E
worldwide for CEN national Members.

Contents Page
European foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Basic principle of the procedure . 9
5 Sampling . 9
5.1 Instruments and materials . 9
5.1.1 General . 9
5.1.2 Sigma-2 passive sampler . 10
5.1.3 Pollen mass filter PMF . 10
5.2 Technical implementation . 12
6 Sampling procedure . 13
6.1 General . 13
6.2 Sampling design . 13
6.2.1 General . 13
6.2.2 Exposure assessment of pollen input in the vicinity of fields with genetically
modified crop (gm-fields) related to a specific GMO and region . 14
6.2.3 Exposure assessment of pollen input for validating and/or calibrating dispersal
models . 15
6.2.4 General monitoring of pollen exposure at larger scales . 15
6.2.5 Assessment of standardized and acceptor specific pollen deposition . 15
6.3 Site conditions . 15
6.4 Installing the equipment . 16
6.5 Exposure time . 17
6.6 Sampling at site . 17
6.6.1 Sigma-2 passive sampler . 17
6.6.2 PMF . 17
6.7 Sample preparation . 18
6.7.1 Preparation of slides for microscopy . 18
6.7.2 Preparation of PMF samples . 19
7 Microscopic pollen analysis . 20
7.1 General . 20
7.2 Sigma-2 passive sampler . 20
7.2.1 Microscopic imaging methods . 20
7.2.2 Qualitative analysis of the pollen diversity . 21
7.2.3 Quantitative analysis of the pollen . 21
7.3 PMF . 21
7.3.1 Microscopic analysis . 21
7.3.2 Qualitative analysis of the pollen (diversity) . 21
7.3.3 Quantitative microscopic analysis of pollen . 21
8 Molecular-biological analyses of GMO . 23
9 Determination of the target parameters for GMO monitoring and representation of
the results . 24
9.1 General . 24
9.2 Sigma-2 passive sampler . 24
9.2.1 Determination of pollen deposition per sampling period . 24
9.2.2 Determination of the daily mean pollen deposition rate per sampling period . 25
9.2.3 Determination of yearly pollen deposition . 25
9.2.4 References to pollen dispersal models . 25
9.3 PMF . 25
9.3.1 Pollen count per sample N . 25
i,PMF
9.3.2 Relative frequency of pollen species i . 26
9.3.3 Determination of pollen flux per sampling period . 26
9.3.4 Determination of the daily mean pollen flux rate per sampling period . 26
9.3.5 Determination of the yearly pollen flux . 27
9.3.6 Assessment of results from molecular-biological analyses . 27
9.3.7 References to pollen dispersal models . 28
10 Performance characteristics of the methods. 28
10.1 General . 28
10.2 Validation . 28
10.3 Distribution of measured values . 29
10.4 Methodical approach and determination of basic parameters. 29
10.5 Sigma-2 passive sampler . 31
10.5.1 Sensitivity, detection limit and reproducibility . 31
10.5.2 Detection confidence level and required numbers of cases . 33
10.6 PMF . 35
10.6.1 Sensitivity, detection limit and reproducibility . 35
10.6.2 Detection confidence level and required numbers of cases . 38
10.7 Parallel measurements. 40
10.8 Comparative measurements using a standard volumetric pollen trap (Hirst type) . 42
10.9 Pollen diversity . 43
11 Quality assurance and quality control . 44
11.1 General monitoring strategy and terms of reference of pollen monitoring with
technical samplers . 44
11.2 Site protocol . 44
11.3 Accompanying documentation for samples . 45
11.4 Parallel measurements. 45
11.5 Comparative measurements using active samplers as calibration bases . 45
11.6 Quality assurance and reference materials . 45
11.7 Qualification . 46
Annex A (normative) Maize-specific requirements . 47
A.1 Scope . 47
A.2 Basic principles . 47
A.3 Sampling . 48
A.4 Sample preparation . 49
A.5 Quantitative microscopic pollen analysis . 50
A.6 Molecular-biological analysis of maize DNA using PCR . 51
A.6.1 General . 51
A.6.2 DNA extraction . 51
A.6.3 Real-time PCR analysis . 51
A.7 Determination of the target parameters for GMO monitoring and assessment of the
results . 52
Bibliography . 53

European foreword
This document (CEN/TS 16817-1:2015) has been prepared by Technical Committee CEN/TC 264 “Air
quality”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
CEN/TS 16817, Ambient air — Monitoring the effects of genetically modified organisms (GMO) — Pollen
monitoring, is composed of the following parts:
— Part 1: Technical pollen sampling using pollen mass filter (PMF) and Sigma-2-sampler [the present
document];
— Part 2: Biological pollen sampling using bee colonies.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Introduction
The European Parliament and the European Council require an environmental risk assessment and a
post-marketing monitoring for any GMO released to the environment [5; 6]. This had to be implied in
national law in any member state of the EC by date.
Pollen dispersal plays a significant role in the dissemination of genetically modified organisms (GMO). A
procedure is described for GMO monitoring that enables quantification and documentation of GMO
input and spread through pollen in a nationwide monitoring network which represents natural
landscapes. Technical and biological pollen sampling (the present Technical Specification and
CEN/TS 16817-2) and molecular biological analysis methods (polymerase chain reaction (PCR) for
DNA; Enzyme-linked immunosorbent assay (ELISA) for proteins) are used for the detection of GMO
input.
It is reasonable to use both technical and biological sampling of pollen, thus they supplement each other
in manifold ways. The technical sampling (i.e. the present document) is conducted with stationary
point-samplers. They give a record of pollen input at the sample site that correlates with the prevailing
wind direction and relative position to the surrounding pollen sources. Bee colonies actively roam an
area and are therefore area related samplers. Further, pollen sampling depends here on the collection
activity of the bees and the availability of pollen sources within the roaming area according to the bees'
preferences and supply of melliferous plants [32].
Presently known pollen traps are only partially suited for GMO monitoring, since they can neither be
standardized nor is the instrumentation designed for exposure times that are suitable for this purpose.
Another limitation of commonly used pollen samplers is the requirement for a power supply, e.g. as for
the Hirst type trap. The use of these instruments is therefore restricted to a limited exposure area.
For these reasons, a new type of passive pollen sampler, the pollen mass filter (PMF), was developed.
The PMF is used either in combination with the Sigma-2 passive sampler or solely.
The present Technical Specification is largely based on German VDI/Guideline 4330 Part 3 [31].
1 Scope
This Technical Specification describes a procedure for the use of the passive samplers Sigma-2 and PMF
to sample airborne pollen. Both are designed to sample coarse aerosol particles. Collected samples are
used to analyse pollen input with regard to pollen type and amount, and input of transgenic pollen. The
Sigma-2 passive sampler here provides a standardized sampling method for direct microscopic pollen
analysis and quantifying the input of airborne pollen at the site. The PMF yields sufficient amounts of
pollen to additionally carry out molecular-biological diagnostics for detection of GMO.
Essential background information on performing GMO monitoring is given in VDI/Guideline 4330
Part 1 [4], which is based on an integrated assessment of temporal and spatial variation of GMO
cultivation (sources of GMO), the exposure in the environment and biological/ecological effects. Ideally,
the pollen sampling using technical samplers for GMO monitoring should be undertaken in combination
with the biological collection of pollen by bees (CEN/TS 16817-2).
The application of technical passive samplers and the use of honey bee colonies as active biological
collectors complement each other in a manifold way when monitoring the exposure to GMO pollen.
Technical samplers provide results regarding the pollen input at the sampling site in a representative
way, whereas with biological sampling by honey bee colonies, pollen from flowering plants in the area
is collected according to the bees' collection activity. Thus, this method represents GMO exposure to
roaming insects. By combining the two sampling methods these two main principles of exposure are
represented. Furthermore, a broad range of pollen species is covered.
The sample design depends on the intended sampling objective. Some examples are given in 6.2.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
1)
VDI 2119:2013-06 , Ambient air measurements — Sampling of atmospheric particles > 2,5 µm on an
acceptor surface using the Sigma-2 passive sampler — Characterisation by optical microscopy and
calculation of number settling rate and mass concentration
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
acceptor surface
natural or manmade collection surface for airborne particles
3.2
concentration
number concentration
number of particles per unit air volume; here number of pollen per m air
3.3
deposition
pollen deposition
deposition of atmospheric particles; here pollen on an acceptor surface

1) For application of the Sigma-2.
3.4
dispersal
pollen dispersal
spread of pollen from the flower/field into the surrounding environment by wind drift
3.5
event
unique DNA recombination event that took place in one plant cell, which was then used to
generate entire transgenic plants
3.6
flux
horizontal flux
number of particles (here pollen) that are drifted horizontally per wind
3.7
genetically modified organism
GMO
organism in which the genetic material has been altered in a way that does not occur naturally by
mating and/or natural recombination
[SOURCE: Directive 2001/18/EC [5], modified — The content of the definition was changed.]
3.8
monitoring
environmental monitoring
characterizing the state and quality of the environment and its changes by measurements/observations
in regard to defined objectives
3.9
pollen
male gametophyte of the flowering plant
3.10
pollen type
species
class of pollen being distinguished by microscopic means on species, family or other order level
3.11
sampler
device for sampling here of pollen
3.12
sampling
pollen sampling
collection of particles, here pollen by technical or biological means
3.13
sedimentation
directed particle movement by gravity (here pollen in the air), which consists in a vertical flux towards
the ground
4 Basic principle of the procedure
For the technical pollen sampling, two passive samplers are used, the PMF and Sigma-2 passive
sampler, either in combination or the PMF solely:
The Sigma-2 passive sampler is designed for determining the pollen deposition rate (dry deposition by
sedimentation). Wind-dispersed pollen grains enter the interior through the laterally shifted slits of the
sampler. The pollen are deposited on an adhesive tray as acceptor (tape, foil, slide) at the bottom of the
sampler. Thus, the deposition takes place in the turbulence-depleted interior of the sampler which
provides protection from wind and rain. Pollen adhering to the adhesive tray are directly analysed with
regard to pollen type and counts by means of light microscopy. For the purpose of GMO monitoring, an
exposure time in the range of four weeks is recommended to be able to cover the main flowering period
of the target plant species with as few sampling periods as possible (the rationale for this is given in
6.5). The microscopic single-particle analysis yields an average pollen deposition rate for the respective
pollen species and time period. Summing up the deposition rates of all sampling periods in the season
yields the total pollen deposition per season/year as target parameter.
The pollen mass filter (PMF) exhibits a 10 times to 100 times higher sampling efficiency, so that pollen
samples can be analysed both microscopically to quantify pollen input and further on, with regard to
possible GMO input by using molecular-biological based methods (e.g. PCR for DNA, ELISA for
proteins/toxins). The PMF consists of a layered hollow filter that is constructed in such a way as to let
the air pass through nearly unopposed. However, coarse aerosol particles bigger than 10 µm, such as
pollen, are retained. A laterally mounted collection flask is used for collecting rainwater. For the PMF,
an exposure time of four weeks is recommended (see 6.5) so that only a few samples are needed to
cover the relevant flowering period. In order to cover a complete blooming period of one or more target
plant species a respective number of exposure (sampling) periods lasting four weeks each can be
carried out.
The Sigma-2 passive sampler collects aerosol particles bigger than 1 µm covering the size range of most
pollen and fungal spores. Its sampling efficiency reaches its limitation towards bigger and heavier
aerosol particles over 60 µm diameter, like e.g. maize pollen. In such cases, the evaluation of pollen
deposition shall be based on the PMF solely.
Field experiments have shown that the method is well suited for environmental monitoring of GMO [14;
17; 20].
5 Sampling
5.1 Instruments and materials
5.1.1 General
The combined sampling equipment consisting of a Sigma-2 passive sampler and PMF is described in
Figure 1. For some tasks the PMF sampler is used solely, e.g. for maize pollen, and/or when it is
necessary to increase the amount of sampled pollen at a site within a certain period (see 10.5.2, e.g. for
keeping detection limits for PCR-analysis of pollen DNA). For such tasks, stacked versions of the PMF
sampler with more than one PMF-unit per sampler are additionally available as shown in Figure 2. The
2 3
) )
complete sampling equipment is available.

2) TIEM technic GbR, Hohenzollernstr. 20, 44135 Dortmund. Samplers are manufactured by the supplier mentioned above. It
is an example of a suitable product. This information is given for the convenience of users of this European Technical
Specification and does not constitute an endorsement by CEN of this product. Equivalent products may be used if they can be
shown to lead to the same results.
3) Breitfuß Messtechnik GmbH, Danziger Str. 20, 27243 Harpstedt. Samplers are manufactured by the supplier mentioned
above. It is an example of a suitable product. This information is given for the convenience of users of this European Technical
5.1.2 Sigma-2 passive sampler
The Sigma-2 device is a passive sampler for coarse atmospheric particles as described in
VDI/Guideline 2119. It consists of a cylindrical sedimentation chamber with a protective hood on top as
inlet.
As acceptor surface for particle deposition, conventional microscopic slides are recommended
(76 mm × 26 mm) with two quadratic acceptor fields (18 mm × 18 mm) coated with weather-proof
adhesive, such as polymeric acrylic ester. The slides are attached to the base with an adapter.
Alternatively adhesive acrylic foil (60 mm × 60 mm), also coated with weather-proof adhesive, on
special adapters can be used, too.
Prepared adhesive foils and slides for sample handling and suitable shipping cans are available from the
supplier mentioned above. It is recommended to use slides with marked acceptor fields (frames with
plotted scales, dots or lines) for facilitating the microscopic pollen analysis. In this TS the handling is
4)
described for slides only.
5.1.3 Pollen mass filter PMF
The PMF consists of:
— filter cladding (depth filter) consisting of a stack of eight filtering discs;
— filter holder conical top, base with distance rods and quick-connect tube coupling;
— collection flask, sheath, connecting tube, floor stand pole, length 2 m, diameter e.g. 34 mm.

Specification and does not constitute an endorsement by CEN of this product. Equivalent products may be used if they can be
shown to lead to the same results.
4) For the handling of foil as acceptor, see Guideline VDI 2119.
Key
1 conical top
2 screwed joint for removing filter discs
3 distance rods
4 filter cladding (consisting of eight stacked filter discs)
5 base with conical outlet
6 quick-connect tube coupling’
7 screw joint to Simga-2 passive sampler
8 complete PMF sampling unit
9 Sigma-2 passive sampler
10 connecting sample tube
11 pole, length 2 m
12 sheath for collection flask
13 collection flask
14 Sigma-2 passive sampler opened
15 base with acceptor surface and adapter
16 sedimentation cylinder
17 inlet (top cover with slits)
18 ground
Figure 1 — Detailed views of the complete sampling equipment [[17]; VDI 2119:2013-06]
a) PMF/Sigma-2 b) PMF-mono c) PMF-duo d) PMF-trio e) PMF-quattro
passive sampler
Figure 2 — Types of technical sampler [Source: TIEM technic GbR]
5.2 Technical implementation
The Sigma-2 passive sampler provides a suitable method for sampling airborne particles including
pollen. This instrument consists of a cylindrical sedimentation chamber which is covered by a
cylindrical hood. Both parts have notches enabling air exchange between the interior of the
sedimentation chamber and ambient air. Inside the chamber with a volume of calmed air particles
suspended in the air sediment onto a transparent adhesive foil or slide that can be removed for
subsequent microscopic analysis. Under the microscope, particles including pollen can be identified and
counted. The average pollen deposition rate for the exposure time is calculated from the pollen count
determined on a defined area on the adhesive carrier exposed over a defined time (see 9.2.1). However,
within the conventional exposure time the amount of pollen collected by the Sigma-2 passive sampler is
insufficient to carry out unambiguous pollen DNA analyses using PCR techniques for the detection of
specific gene sequences such as transgenes.
In order to collect sufficient amounts of pollen for molecular-biological analyses the passive sampler
PMF was developed.
The PMF consists of a filter holder with filter cladding as sampling unit, collection flask, and connecting
tube. The PMF sampling unit is screwed on top of the Sigma-2 passive sampler or used solely with an
adapter. The PMF sampling units can be stacked up to four units per pole.
The PMF filter cladding provides a low aerodynamic resistance and flux of ambient air through the
filter. In addition, the characteristics of the filter material ensure that pollen and other particles larger
than 10 µm in diameter can attach and adhere to the surface of the fibres. If it rains, some of the pollen
and other particles can be washed off the surface of the fibres. Therefore, the rainwater is collected in
the collection flask. The samples for downstream analyses are extracted from the filter material and
from the rainwater in the collection flask using a sample preparation procedure.
— Filter holder (Figure 1, parts 1, 2, 3, 5, 6, and 7):
The filter holder consists of the conical top and the base part.
The conical shape of the top prevents birds from landing on it.
Three distance rods in the base part form a track for the filtering discs. The rods’ length determines the
height of the filter cladding and the pressure between the filtering discs.
Rain water is collected in the flanged collar of the base part, the bottom of which is conical – thus, water
is drained off through the quick-connect coupling and connecting tube into the collection flask.
The conical top of the filter holder can be screwed off in order to insert the filter cladding.
Components are made up of inert materials (e.g. aluminium with an anodized surface, stainless steel).
— Filter cladding (Figure 1, part 4):
The filter cladding consists of eight filtering discs layered on top of each other.
The annulate filtering discs have an outer diameter of 80 mm, while the centre-hole is 30 mm in
diameter. Discs are punched out from a flat 20 mm thick depth filter fleece. The fleece is made of
thermally bound and progressively layered polypropylene fibres.
For the horizontal wind component the effective flux cross-section (height × width) of the filter cladding
is 100 mm × 80 mm = 0,008 m for all wind directions. Filter dimension and material are characterized
by a low flux drag and back pressure.
— Connecting tube (Figure 1, part 10):
Polyamide tubes with an outer diameter of 6 mm and a wall thickness of 1 mm have proven to be
effective as inert connecting tubes.
— Collection flask (Figure 1, part 13):
Clean 1,5-l PET collection flasks with flat, round bottoms are suitable for the average amount of rain-fall
in Germany and sampling times of four weeks. In cases of extreme high rainfall during the sampling
period (approx. more than 120 l/m ), the overflow of the bottle will start. This will not affect the
sampled amount of pollen though because they sediment to the bottle base. For record of the complete
amount of rainfall in regions with higher precipitation, bigger flasks and container might be used or the
flask might be changed intermediately. For visual inspection the collection flask should be transparent,
but during sampling time it shall be protected from daylight by aluminium foil and placed into an
opaque sheath (Figure 1, part 12).
— Floor stand (Figure 1, part 11):
All components of the pollen sampling equipment are mounted onto a floor stand: the Sigma-2 passive
sampler with the PMF screwed on top of it, and the collection flask underneath, so that sample liquid
can drain off easily.
A pole of 2 m in length with an outer diameter of 34 mm is suitable. It is helpful to drill an 11-mm wide
hole through the pole 0,5 m from the bottom end, through which a stabilizing rod can be inserted. This
facilitates sinking the floor stand 0,5 m into the ground.
6 Sampling procedure
6.1 General
For documentation purpose, a protocol about sampling and site conditions needs to be prepared
(see 11.2).
6.2 Sampling design
6.2.1 General
The sample design depends on the intended monitoring objective. Some examples are given here:
6.2.2 Exposure assessment of pollen input in the vicinity of fields with genetically modified crop
(gm-fields) related to a specific GMO and region
a) Potential tasks: Risk assessment and management, definition of appropriate buffer distances.
b) Examples:
1) Bt-maize cultivation in the vicinity of nature reserve areas inhabited by sensitive non-target
organisms;
2) pollen input of gm-oil seed rape cultivation to neighbouring fields.
The technical pollen samplers are distributed in the vicinity of the gm-field(s) in such a way that the
spatial distribution of pollen exposure and its gradients can be assessed in a representative way.
The samplers are placed around the field(s) in different distances from the respective field up to
further distances (reference areas), covering various wind directions. As the dispersal of pollen
follows a power function in relation to distance, a nonlinear, logarithmic distance scale shall be
applied. The sample design depends largely on the availability of secondary data relevant to pollen
dispersal, e.g. meteorological data like wind direction and velocity.
c) For optimal results, a prospective dispersal modelling shall be applied leading to a prospective
spatial distribution of pollen input in the area. The advantage of this is that only few sample points
are necessary to calibrate the gradients of the model at selected sites with the technical pollen
samplers delivering a reliable picture of the spatial distribution of pollen exposure over the
complete area. Furthermore, scenarios can be modelled for predictions of distinct conditions based
on long-term records of the meteorological services, e.g. statistically rare events (10-years, 100-
years events), worst case situations, favourable field arrangements, variable buffer zones.
Depending on the complexity of the configuration of gm-field(s) and the topography, as a rough
estimate about 20 to 50 sample points shall be calculated. This is given by the rationale of five to
seven classes of exposure intensity (nonlinear, logarithmic) and four to eight wind sectors.
Examples are given in the literature by [8; 17; 26].
d) For simple approaches without dispersal modelling, tests of gradients of exposure by distance from
the field(s) at selected directions are possible. At least seven sample points are necessary for
testing the gradient in respect to one gm-field. Thus the decline follows a potential function, the
sample points shall be equally distributed on a log scale of distance. For more advanced
approaches, considering changing wind directions, a y-shaped design using at least 12 sample
points is recommended. Both approaches are only possible due to the availability of a broad
reference database for this standardized method gained over more than 10 years of field surveys
[18]. Without detailed data on weather conditions, e.g. wind direction and velocity, temperature,
humidity and thermal stability, and the temporal course of pollen release rates, however, no
interferences can be made on the spatial distribution in the area. Examples in the literature are
given by [14; 20].
e) For assessment of the spatial distribution of pollen exposure in a region without the help of
dispersal modelling, a greater number of sample sites would be necessary. There are various
approaches commonly applied for such tasks, the choice of which depends on the sampling
objective in detail. A common approach is a sampling grid. A grid is laid over the region; in every
grid one sample shall be taken. For example, a region of 10 km × 10 km shall be monitored. A grid of
1 km side length would lead to 100 raster fields; i.e. a number of 100 sample points would be
necessary. A grid length of 1 km is very large for pollen dispersal, but a more appropriate grid
length of 100 m would already lead to 10 000 sample points. Despite the large number of samples
points needed, the results would be poor compared to the approach described under a). Moreover,
the linear scale of the grid results in a great number of sites in the outer range with only little
changes in the pollen input and only few sample points at the areas of interest with greater changes
at closer distances. In case the location of the gm-fields is known, a nonlinear grid around the gm-
fields in the centre, with increasing grid sizes by distance from the field could be applied. However,
still large numbers in the order of 100 sample points and more would be required.
6.2.3 Exposure assessment of pollen input for validating and/or calibrating dispersal models
The various pollen species vary in size and shape and differ in their dispersal behaviour in the air.
Therefore, a validation and calibration of the dispersion models shall be undertaken in general for any
pollen species before application. Secondly, because the release rates of pollen are usually not known in
detail, for any application of dispersal modelling a calibration shall be done by field measurements of
the pollen input. The number of needed sites depends on the specific task and conditions in the
environment; an approximate number in order of 10 to 30 sample points seems appropriate.
6.2.4 General monitoring of pollen exposure at larger scales
— Task: GMO monitoring on larger scales:
This task compares to other fields of environmental monitoring. Due to the disadvantages of static grid
designs (see 6.2.2 e)), more advanced approaches might be appropriate, for example by use of dispersal
models [26]. In general, the linkage of the sample design for GMO monitoring to the distribution of the
pollen sources, e.g. the location of gm-fields, seems obvious. Nevertheless, the changing pattern of crop
cultivation shall be taken into account as well as the fact that the cultivation pattern varies from crop to
crop and from year to year. This implies a sophisticated sample design, being capable to assess changes
in the temporal and spatial distribution of pollen exposure as well as being able to integrate new GMOs.
In this context, a prerequisite for any monitoring method is a standardized measurement of exposure
guara
...