Summary Statement: Bioaerosol Assessment
Julia Coulthard
Prepared by:
Ahlim Hashm
Approved by:
Conrad House
Beaufort Square
Chepstow
Monmouthshire
NP16 5EP
Tel
Fax
Email
01291 621821
01291 627827
rpssw@rpsgroup.com
JER3449
Revision: 0
November 2006
This report has been produced by RPS within the terms of the contract with the client and taking
account of the resources devoted to it by agreement with the client.
We disclaim any responsibility to the client and others in respect of any matters outside the
scope of the above.
This report is confidential to the client and we accept no responsibility of whatsoever nature to
third parties to whom this report, or any part thereof, is made known. Any such party relies on
the report at their own risk
Planning, Transport & Environment
Summary Statement : Bioaerosl Assessment
Contents
1
Introduction ..................................................................................... 1
2
Elevated Levels of Bioaerosols Can and Do Cause Problems
Despite Lower Levels Occurring Naturally .............................................. 2
2.1
High Concentrations of Bioaerosols from Open Windrow Sites ........................... 2
2.2
Failure to Recognise the Implications of the Scale of the Operation .................... 3
2.3
The Effect of Other Farming Activities .................................................................... 3
2.4
In Conclusion ............................................................................................................ 4
3
The Health Effects of Bioaerosols. .................................................. 5
3.1
The true health Impact of Composting Operations ................................................ 5
3.2
Concern about the nearby Primary School ............................................................. 6
4
The Entire Village of Old Sodbury is at Risk Regardless of the
250 m limit. ............................................................................................. 7
4.1
Distance to the Receptors ........................................................................................ 7
4.2
The 250m Limit is Guidance Only. ........................................................................... 7
5
Sensitive receptors could be affected 55 days a year or more ........ 8
5.1
Meteorological Data and Temperature Inversion .................................................... 8
5.2
The Commercial Realities of Operating a Composting Site................................... 9
6
Conclusions and Recommendations ............................................. 10
6.1
Odour ....................................................................................................................... 10
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Summary Statement : Bioaerosl Assessment
Appendices
Appendix A
Supporting Scientific Evidence for the Summary Statement Reviewing
the Quality and Accuracy of the Bioaerosol Assessment Written by Dr
John Burden Regarding Southcroft Farm, Old Sodbury
Appendix B
Map of Houses Within 250m
Appendix C
Number of Houses Within 250m of Compost Farm
Appendix D
CV – Ahlim Hashm
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1
Introduction
Our client has asked us to undertake a review of:

the ‘Desk Top Bioaerosol assessment of the Green Waste Composting Facility
for Southcroft Farm’ written by Dr John Burden;

the additional documentation provided by Gill Pawson (planning agent) and

the quality of the Environment Agency’s written response
in support of the planning application PK06/1770/k to make permanent an open
windrow composting facility at Southcroft Farm, Old Sodbury.
In so doing we have considered whether the information and data provided is
suitable to assess the potential impact on human health and whether it complies with
the current UK guidance on risk assessment from composting facilities.
The EA’s policy document ‘Agency position on composting and health effect’ states
“all permit applications or modifications should be accompanied by a site-specific risk
assessment. Where an operation is proposed within 250 metres of a sensitive
receptor, there will be a presumption against permitting or exempting unless the site
specific risk assessment based on sound, independent, scientific evidence which
demonstrates that appropriate levels can be achieved and maintained at any working
or dwelling place whose boundary lies within 250 metres of the boundary of the site
for which the permit has been applied”.
It is our opinion that the submitted report fails to meet the above risk assessment
principles. The report is very generic, extremely vague and occasionally makes
contradictory statements.
The only justification provided by the EA for not demanding that the applicant should
carry out a site specific risk assessment using the source-pathway-receptor concept
is the operator’s lack of knowledge on the source term (the amount and type of
bioaerosols which have been and will be produced by the site).
We, however, believe that identifying the source term is the responsibility and duty of
the operator (certainly not the residents) and is not a reason for failing to follow the
current EA guidance on risk assessment.
In addition the assessment has based its conclusion wholly on four key criteria,
which in our opinion are all misleading and fatally flawed.
We take each of these in turn and discuss why it is not appropriate to rely on the
argument provided.
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2
Elevated Levels of Bioaerosols Can and Do Cause
Problems Despite Lower Levels Occurring Naturally
The assessment recognises that the composting process can result in the production
of high concentrations of bioaerosols within the material being composted’ and that
‘in some situations populations as high as 109 with bacteria, 108 with actinomycetes
and 106 with fungi per gram can be recorded on materials being composted’.
However, the report then compares these levels with the natural occurrence of
bioaerosols in some natural environments. Indeed it states, WITH NO
ACCEPTABLE JUSTIFICATION that ‘the background levels of bioaerosols in
woodlands and farms are higher than that in a composting yard.’
2.1
High Concentrations of Bioaerosols from Open Windrow Sites
In this document we demonstrate clearly that potential emissions of bioaerosols from
composting facilities can be significant particularly from open windrow composting
systems. Using general statements on issues related to emissions without reference
to the type of composting system (such as those given in Dr Burden’s assessment)
can be very misleading.
Our literature review reveals that emissions can be very high and that the open
windrow type of composting facility is known and confirmed to have the highest
emission levels when compared to partially enclosed and enclosed composting
systems. Please make reference to the attached technical review (appendix 1) in
relation to published literature levels of emissions from the different types of facilities.
The EA document ‘Agency position on composting and health effects’ states that
levels of bacteria and fungi released are significant and in particular, one fungus,
Aspergillus Fumigatus, a class 2 pathogen, can be present in sufficient
concentrations to give rise to adverse health effects in humans.
A report on ‘Bioaerosol Monitoring and Dispersion from Composting Sites’ by South
West Industrial Crops Limited stated that “factors such as the type of system used
for composting (e.g. open windrow or enclosed “in-vessel”), the feedstock material
being composted and the way that sites are managed, are likely to have an influence
on the level of bioaerosol emissions. Lower cost outdoor windrow composting
system may, for example, have potential for application on a large number of sites.
However, there may be the greatest concern about bioaerosol emissions from these
systems. Such sites may well need to be selected with due regard to separation
distances from potential sensitive receptors, and they may need to be managed to
minimise the impact of bioaerosol emission”.
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2.2
Failure to Recognise the Implications of the Scale of the Operation
In the absence of any significant bioaerosol sources, natural atmospheric conditions
in typical suburban areas are reported to be significantly lower than those in areas
affected by industrial sources including those affected by composting type of
facilities.
We agree that the microbial components of bioaerosols generated during the
composting process contain many of the same micro-organisms that are commonly
isolated from normal outdoor air.
HOWEVER THE REPORT SEEMS TO IGNORE THE MAIN DIFFERENCE -THE
SCALE.
The handling of large quantities of compost potentially can lead to the release into
the air of large quantities of the bacteria, fungi and actinomycetes and their
components, found in compost as a bioaerosols.
We agree with the first half of Appendix D (extracted from the HSE report) which
demonstrates the increased level of bioaerosols in certain farm related activities.
However the reported emission from composting facilities in the second half are
debatable as the levels of emissions are dependant on the type of facilities, the type
of waste they handle and the utilised control measures as discussed above. As
stated before, open windrows are the worst in terms of high emission levels and
general values relevant to other types of facilities should not be quoted for a
comparison purpose.
2.3
The Effect of Other Farming Activities
Dr Burden’s assessment also made reference to the presence of many other faming
activities which have the potential to increase the levels of bioaerosols. We agree
with the EA position revealed in their letter dated 15th of September, 2006, that the
presence of other sources of bioaerosols is not a reason for allowing additional
loading from a composting operation. The EA has requested that the risk
assessment shows that the additional loading from the composting activities will not
raise existing levels above background or the agency’s threshold for acceptable
levels. Yet the reply letter provided by Mrs Gill Pawson failed to do this and simply
stated that “we are not aware of any agency thresholds “.
The EA has provided commonly recognised “acceptable concentrations of the key
components of bioaerosols”. These are:

1000cfu/m3
total bacteria

1000cfu/m3
total fungi

300cfu/m3
gram-negative bacteria
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2.4
In Conclusion
In allowing for potential contributions from other farming activities in the area, and
using the indicative concentrations provided in appendix D of the report, it is evident
that the site is not the best location for permitting an activity that will contribute to the
background level of bioaerosols which already, according to the report is significantly
loaded with bioaerosols. The overall concentrations will therefore be significantly
higher than the EA recommended reference concentrations and certainly above the
background concentration in a normal suburban area.
One would assume that in highly impacted area by certain type of pollutants,
additional emission from a new facility should be heavily controlled to reduce the
level of that pollutant in the area.
In following the examples set for other UK industries regulated by IPPC, when
assessing potential impact on air quality from a proposed facility, consideration of the
background contribution from other pollution sources should be taken into account
and when a release from an installation constitutes a major proportion of an
Environmental benchmark, or makes a major contribution to the breach of this
benchmark, then this may not be judged to be acceptable. Where the benchmark is
already exceeded or may be exceeded as a result of an additional contribution from
a proposed installation, consideration of further control measures may be needed to
be taken
We are not suggesting that these regulations apply to the proposed installation
however, common sense would dictate that this should be the approach adopted
rather than trying to dismiss the significance of potential risk by the presence of other
sources in the area.
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3
The Health Effects of Bioaerosols.
The submitted bioaerosol assessment recognises that ‘bioaerosols in high numbers
for extended periods, can be detrimental to sensitive individuals’; but concludes that
‘composting operations pose no greater threat than other industrial or agricultural
activities and that evidence is available to show that only a very small proportion of
the population are sensitised by bioaerosols’.
3.1
The true health Impact of Composting Operations
In terms of the potential health impact from exposure to bioaerosols, Section 6 of the
HSE review identifies different potential health problems based on a review of a
wealth of published data regarding known health effects from organic dust. This
report identifies members of the public living in the vicinity of waste composting sites
and member of the public passing by the periphery of waste composting sites as
some of those potentially at risk to a greater or lesser degree.
Exposure to the micro-organisms found in compost could potentially cause ill-health
in the people exposed to them either by infection, allergy or an adverse response to
toxins.
Some of the micro-organisms which increase in number during the composting
process are toxic and/or allergic.
Even after the microbial cells have ceased metabolic activity and entered a resting or
non-culturable but viable stage or for a period after cell death before proteinaceous
components have degraded, there is still the potential for microbial cells to be toxic
or allergenic.
According to Dr Toni Gladding in a presentation for the sustainable Organic
Resources Partnership and many other documents including the HSE report, health
effects associated with bioaerosol include:

Infections: caused by pathogens capable of invading body tissues and
growing

Allergy: immunological response that results in the body becoming
“sensitised” following exposure
o
Respiratory sensitisers
o
Non-specific inflammatory reactions
o
Predisposition/atopy

Gastrointestinal: hygiene issues

Hyperactive airways: inflammation on exposure (increased susceptibility to
other chest illnesses)
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
Allergic rhinitis & Asthma: allergy based

Chronic bronchitis and chronic obstructive pulmonary disease (COPD)

Extrinsic allergic alveolitis or granulomatous pneumonitis- more applicable to
occupational exposure

Acute Toxic Pneumonitis (organic dust toxic syndrome-ODTS)-Fever and flu
like symptoms, headaches, muscle pains, chest tightness 2-6 hrs after
exposure (toxic alveolitis- thought to be toxic not allergic) usually occurs
during or shortly after, high exposure to airborne dust.

Chronic ODTS: chronic muscle pains, tiredness, shortness of breath.

Chronic sinusitis: dizziness, chronic cold etc
It should be noted that some of these ill health effects are associated with short-term
exposure. Furthermore sensitisation could be caused by non-viable bioaerosols
such as endotoxins (macromolecule with a lipopolysaccharide core, found in the cell
walls of all gram-negative bacteria), mycotoxins (non-volatile low molecular weight
toxic secondary metabolites produced by some species of fungi during their growth
in organic materials) and Glucans (a polyglucose compound in the cell walls of fungi,
some bacteria and plants).
3.2
Concern about the nearby Primary School
The site is close to the local primary school where 60+ children attend. It is generally
accepted that young children can be particularly susceptible to the effect of
environmental pollutants and therefore were identified in the current UK guidance to
risk assessment to human health by DEFRA and the EA as the most sensitive
receptors. The headmaster has written a letter of objection in which he states” on
numerous occasions when the site was in operation the smell was so strong and so
unpleasant that it made normal conduct of school life very difficult. It was, on several
occasions, impossible to allow children to use the playground at break times and
windows, especially those on the mezzanine floor had to remain closed to the great
discomfort of the pupils and staff”.
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4
The Entire Village of Old Sodbury is at Risk
Regardless of the 250 m limit.
4.1
Distance to the Receptors
The locals, and a firm of Chartered Land Surveyors, Lewis Brown, have undertaken
several measurements all of which prove that the distance to the receptors is less
than the 250m.
In the professional survey the measurements have erroneously been taken from the
edge of the ‘impermeable pad’ and not the composting facility nor even the
composting ‘bund’ within which it is clear composting activity has taken place
(appendix 2) .
In fact the EA guidance on this is clear; distances should be taken from the
boundary of the facility, which in no way limits the distance to the composting pad.
The residents of Old Sodbury have photographs which prove that a great deal of the
composting activity has taken place immediately behind the bund (outline marked
appendix 2) on the western part or Church Lane side of the facility. Indeed officers
from the EA have noted on a number of occasions that the activity was not confined
to the composting pad (letter from Jim Dadd, 25th May 2005) but still the bund
remains.
In summary therefore the 250 metre line is likely to encompass many more than 9
dwellings. The residents have drawn up a list of 36 houses, 1 business and a school
within this 250 m circle (appendix 3).
Even on the erroneous map provided the 250 m line encompasses the school field (it
has planning permission to turn it to astro) yet this is not listed in the dwellings
affected.
4.2
The 250m Limit is Guidance Only.
However and more importantly, this 250 m criterion is a mere guidance and can not
be used as an argument for dismissing the need for a proper site specific risk
assessment where ill health and nuisance problem were already identified.
Furthermore, the HSE Report 2003 stated clearly that “while most published studies
indicate that bioaerosols are reduced to background within 250m distance currently
prescribed by the EA for risk assessment purposes, some experimental studies and
dispersion modelling exercises suggest that bioaerosols sometimes may exceed
concentrations chosen as background levels at distances greater than 250m.
Considering that there have been reports of ill health from the residents in the
vicinity, this criterion cannot be used to dismiss potential effect, as migration of
contaminants is usually site specific and can be affected by the local conditions
including metrology and topography.
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5
Sensitive Receptors Could be Affected 55 Days a Year
or More
In terms of the fourth criteria, the assessor has presumed that in reporting that the
prevailing wind is predominantly away from the nearest sensitive receptor and that
the wind only blows in the direction of the village for 15% of the time he is producing
adequate evidence to dismiss the significance of potential risk.
Considering that the EA recommended assessment criteria for bacteria, fungi and
gram-negative bacteria of 1000 cfu/m3, 1000cfu/m3 and 300cfu/m3 are for the 8-hour
and 1-hour averages respectively, having elevated concentrations exceeding the
assessment criteria even for only 15% of the year (55 days) is still presenting a
serious problem. This is especially important considering that some of the ill effects
such as Organic Dust Toxic Syndrome which is associated with short-term exposure
to high levels of airborne organic dust.
5.1
Meteorological Data and Temperature Inversion
It should also be noted that the Dr Burden’s bioaerosol assessment only considered
wind data in a very simplistic manner, using wind rose data from Filton to establish
the prevailing wind conditions.
In our opinion this will not provide a good interpretation of the air movement and
consequently the dispersion of pollutants in the vicinity of the site. We cannot stress
too highly The meteorological data required should include, in addition to wind
speed and wind direction, other surface data such as atmospheric stability and
atmospheric temperature.
Temperature is a factor of paramount importance in deciding the dispersion of
pollutants.
For instance, at night, with clear skies, cooling occurs as considerable outgoing
infrared radiation leaves the earth’s surface. With light winds, the surface and
adjacent air layers cool, resulting in a temperature inversion (temperature increasing
with height instead of the usual cooling with height). The result is extremely stable
conditions with almost no vertical exchange between air layers. Stable conditions
inhibit the vertical motions; however, the spreading in the horizontal direction can
also be very narrow.
These extremely stable conditions cause the highest ground-level concentrations
from surface and near surface releases (such as those from windrows). The light
winds that accompany the extreme surface inversion formation also contribute to the
high concentration from surface releases (Physics of the atmosphere-Fundamentals
of Dispersion modelling-Trinity).
Therefore stable conditions will NOT decrease the concentration of bioaerosols due
to deposition, as it is associated with light wind close to the earth surface, that can
and will carry the pollutants away from the source with little very limited dilution. In
this case therefore such pollutants are likely therefore to be deposited on the nearby
receptors including the village of Old Sodbury.
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Indeed it ties in with the phenomenon of early morning and evening odour/health
problems reported by the residents.
5.2
The Commercial Realities of Operating a Composting Site.
The report suggested that turning windrows will only take place when the wind is
away from the properties in the village. In practice, a commercial business, where
optimum composting conditions are achieved by regular turning of windrows
(employing men for this purpose) cannot cease activity when the weather conditions
are unfavourable.
Also it is unlikely that expensive pre-booked screening and shredding equipment will
be turned away because the weather conditions dictate they should be.
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6
Conclusions and Recommendations
In conclusion, it is our opinion that the bioaerosol assessment for the subject site has
failed to undertake a sound site-specific risk assessment that demonstrates that
appropriate levels can be achieved and maintained at any working or dwelling place
in the area.
6.1
Odour
It should be noted that, although release of odour from composting facilities is as
critical in respect of potential impact on sensitive receptors as bioaerosols, no effort
was made to carry out an assessment to this element.
Odour assessment is well established in the UK based on the current UK guidance
“Technical Guidance Note- Horizontal guidance for odour“.The aim of an odour
assessment, according to this guidance is :

To predict the exposure of sensitive receptors

To indicate the amount of abatement

Improvement or worsening performance over a period of time

Determine compliance

Investigate complaints
The guidance states that a qualitative estimation of the risk can be undertaken in
terms of whether the release is likely to cause a problem or not. However as the risk
of causing annoyance increases, and/or a HISTORY OF ODOUR COMPLAINTS OR
ANNOYANCE ALREADY EXISTS, then so will the need for a more in-depth
assessment that takes a more quantitative approach.
The EA guidance in part 2 states “where the odour emission rate from a source is
known by measurement, or can be estimated, the odour concentration in the vicinity
can be predicted by means of dispersion modelling”. To visualise the extent of odour
impact it is useful to produce contour plots showing odour concentrations around the
source or highlighting where concentrations exceed the appropriate exposure
benchmark which relates to acceptability.
Appendix 4 of part 1 of the guidance covers the subject in more detail and proposes
a “recommended” approach to odour modelling aimed at bringing about consistency
of approach. The guidance states, “There may be circumstances in which there is a
valid reason for taking a different approach and the proposed parameters do not
exclude this, provided that the methodology is described and justification given.
“Benchmarks” are described in Appendix 5 and 6 of part 1 of the guidance”.
Indicative odour exposure criteria for ground level concentration of mixture of
odorants are set based on the offensiveness of odour. For highly offensive odour
such as that from activities involving putrescible waste , the indicative criteria is set to
1.5 ouE /m3.
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On mitigation measures, the guidance states that ”a simple and effective way for the
operators of odorous operations to minimise odour complaints has been to locate
their process(es) as far as way as possible from inhabited areas”.To demonstrate
the importance of the impact of odour, planning permission is required for certain
odorous facilities within a distance of 400m from the boundary of any protected
buildings (e.g houses and schools) as an incentive for .operators to site any new
process at least 400m away from the nearest protected building. The guidance
carries on identifying good housekeeping and building design to have significant
effects on odour reduction. The guidance dismisses tree planting and earth banking
as a solution for dealing with odour problems and states that “ there is no conclusive
evidence to show any real and sustained odour removal or dispersion effect resulting
from landscaping.”
Considering the facts:
 that the released odour is highly offensive, due to the nature of the process;
 there is no containment of the operations, being an outdoor windrow facility;
 the village of Old Sodbury lies within 400m of the site
the proposed odour management plan, submitted without a proper risk assessment,
is not considered adequate or appropriate.
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Appendices
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Appendix A
Supporting Scientific Evidence for the Summary Statement Reviewing the
Quality and Accuracy of the Bioaerosol Assessment Written by Dr John
Burden Regarding Southcroft Farm, Old Sodbury.
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Supporting scientific evidence for the summary statement reviewing the
quality and accuracy of the bioaerosol assessment written by Dr John
Burden regarding Southcroft Farm, Old Sodbury.
Bioaerosols: UK Recommended Assessment Methodology
The key aim of any environmental impact assessment is to identify and assess potential
harms to human and other environmental receptors from any identified sources at the
assessed site. The assessment procedure should utilise the source-pathway-receptor
concept in constructing a site conceptual model (SCM) and assessing potential impact.
The conceptual model, focussing particularly on site specific characteristics, is usually
based on an initial evaluation of available data that characterises the sources of emission
and identifies all possible pathways connecting the sources to sensitive receptors both on
and beyond the site. As the assessment progresses the conceptual site model is continually
refined within the context of the impact linkage.
To present information in a manner consistent with the Source-Pathway-Receptor concept
and to assist in evaluating the possible impacts of releases from the site on human
wellbeing, the SCM should establish, in a qualitative manner, the sources of emissions,
potential pathways of exposure, and potential receptors as follows:

Principal sources of emissions;

Substances of primary concern (odour, bioaerosols, etc);

Behaviour of the emitted substance within the affected media (air);

All potential receptors;

Location of potential exposure points;

Likely migration pathways for the emitted substances to move off-site;

Plausible pathways connecting sources and sensitive receptors;

All significant impact linkages associated with the site.
An assessment of releases and dispersion of odour and bioaerosols is usually required
where emission sources(s) from a composting facility are located in an area within which
sensitive receptors are residing or working. Potential impacts from the releases and
dispersion of the pollutants with considerations to the prevailing meteorological conditions
for that location, and the proximity of the sensitive locations to the emission sources giving
rise to health impact or nuisance are therefore required to be assessed.
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The EA reported that Bioaerosols assessment is only required where the boundary of the
facility is within 250m of sensitive receptors3. The composting association defines sensitive
receptors as ‘any building, other structure or installation, in which at least one person
normally lives or works, other than a building, structure or installation within the same
ownership or controls as the operator/owner of the composting facility2.’
It should be noted that the Health and Safety Executive report 20036 stated that ‘while most
published studies indicate that bioaerosols are reduced to background within the 250m
distance currently prescribed by the environment Agency for risk assessment purposes,
some experimental studies and dispersion modelling exercises suggest that bioaerosols
sometimes may exceed concentrations chosen as background levels at distances greater
that 250m.’
It can be concluded from the above that the submitted report fails to meet the basic
requirement of any risk assessment by failing to present the sources, pathways of exposure
and receptors in a concise and clear manner. This is especially important considering that a
number of receptors are located within less than 250m distance from the installation.
The bioaerosols risk assessment was based mainly on the wind rose for the area. The
assessor has presumed, by reporting that the prevailing wind is predominantly away from
the nearest sensitive receptors it mainly impinges on open countryside and that the wind
only blowing in the direction of the village of Old Sodbury for 15% of the year is adequate
evidence to dismiss the significance of potential effect.
Considering that the EA
recommended assessment criteria for bacteria, fungi and gram-negative bacteria of 1000
cfu/m3, 1000 cfu/m3, and 300 cfu/m3 are for the 8-hour and 1-hour averages respectively,
having elevated concentrations exceeding the assessment criteria even for only 15% of the
year (55 days) is still presenting a potential health problem.
The bioaerosol risk assessment report stated that ’composting process can result in the
production of high concentrations of bioaerosols within the material being composted and
that in some situations populations as high as 109 with bacteria, 108 with actinomycetes and
106 with fungi per gram can be recorded on material being composted.’ Nevertheless the
report still compared it with the natural occurrence of bioaerosol in some natural
environments which totally ignores the scale of production of bioaerosols in open windrow
type of facilities.
Schilling et al (1999) compared an enclosed composting plant with biofilter with a partly
open plant. The researcher found that fungal spores and Aspergillus fumigatus were up to
500 and 400cfu/m3 at 50m from the enclosed plant in comparison to 6,000 and 7000cfu/m 3
of these bioaerosols at a greater distance of 100m from the partially closed plant.
Danneberg et al (1997) has found that the exhaust air emitted from biofilter contained 33
cfu/m3 bacteria and 600cfu/m3 Aspergillus fumigatus (fungi) in comparison to 76,000 cfu/m 3
and 2000cfu/m3 of these bioaerosols in the location of the rotating sieve of a box-system
composting plant.
In comparison, Tovalen et al (1998) reported a thorough investigation of bioaerosols from
outdoor composting source separated biowastes in Finland. The compost was processed
outdoors. Concentrations of airborne microbes were high especially during crushing of
fresh waste and turning of compost. Both bacterial and fungal were higher in the summer
when the compost was dry.
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Maricou et al (1998) reported that the airborne counts of total bacteria, fungi and yeast at a
large indoor composting plant were up to 100 times higher within the inside of the
composting halls in comparison to the levels outside.
It can be seen from the above that bioaerosol emissions from open windrow operations such
as that proposed for the subject site is significantly higher than those generated at enclosed
facilities.
Recommended Methods for Assessment of Bioaerosols
A study undertaken by the HSE and the composting Association with the objective of
critically reviewing published literature related to studies of air-borne micro—organisms or
their constituent parts (bioaerosols) associated with organic waste composting facilities. One
of the considerations was that airborne dispersal of bioaerosols from compost facilities could
affect neighbouring facilities or residents, leading to health concerns.
The report stated that bioaerosols concentrations decline with distance from source due to
atmospheric dispersion and dilution and that mathematical and computational models can
be used to estimate this dispersion and to examine the effects that different atmospheric
stability classes have on reduction of bioaerosol concentrations.
There are few papers that specifically address the modelling of dispersion of bioaerosols
from composting.
In some instances, modelling has been used to estimate bioaerosol emission rates based
on measurements of bioaerosols made at distance from source. These emission rates have
then been used in calculations to examine dispersion under conditions for which no
measurements have been undertaken.
Millner et al (1980) describe concentration measurements and dispersion modelling of
Aspergillus fumigatus, released from composting sewage sludge when disturbed due to
turning. Emission rates were estimated using a Gaussian dispersion model (Pasquill, 1961)
by fitting 31 individual concentration measurements, taken at distances from 10 - 620m. The
calculated emission rates varied from 2.3x104 to 6.7x1010 Aspergillus fumigatus particles per
second. It was assumed that the Aspergillus fumigatus spores were sufficiently small that a
Gaussian dispersion model was appropriate and deposition was not modelled.
Also it was assumed that for the times and distances considered viability of Aspergillus
fumigatus spores was not an issue. Based on the calculated emission rates, and ‘some
judgement’, an effective emission rate of 4.6x106 Aspergillus fumigatus particles per second
was then used in calculations examining the effect of different atmospheric conditions on
dispersion.
In this modelling the actual release was considered to occur from the bucket of a front end
loader above the windrow. A release height representing this was used as being 5m a front
end loader bucket mouth area of 2.8m2 was assumed as the source area. They reported
that a possible alternative representation of the source would have been an area, or volume,
with uniform concentration.
These calculations found that under unstable atmospheric conditions background
concentrations were approached 0.5 to 0.6km downwind of the source. The fact that there
were variations in emission rates between compost piles containing similar concentrations of
Aspergillus fumigatus was mentioned to explain at least some of the range of calculated
emission rates.
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Summary Statement : Bioaerosl Assessment
Danneberg et al (1997) made concentration measurements and used these to estimate
emission rates by modelling dispersion. Concentrations were measured downwind of a
composting plant at points on four lines, 45º apart, originating at the plant. Three samples
were taken at each point. The emission rate of Aspergillus fumigatus was calculated using
the mean of the concentrations measured at 150m downwind. The emission rate was then
estimated using two models, one a regulatory dispersion model from the German Technical
Instructions on Air Quality Control, TA Luft, (1986), the other an expression developed to
examine NOx emissions from tall chimneys.
The models were found to give emission rate of 1.25x107 of total bacteria per second. This
value was considered to be roughly in the same order of magnitude to those calculated by
Millner et al (1980) for Aspergillus fumigatus. Dispersion calculations using the estimated
emission rate indicated that concentrations were less than 500 cfu/m3 at 500m; this
concentration was assumed to be equivalent to background concentration.
From the above discussed details of the EA work and the HSE review for a number of
composting facilities, it can be concluded that although using simplistic dispersion modelling
of the Bioaerosol plume was proven not very effective (over-conservative) for bioaerosols,
the modelling can be used to predict concentrations in the context of differing atmospheric
conditions and the likelihood of different exposure levels and durations. It is a common
practice nowadays to use dispersion models to predict the concentrations of bioaerosols at
identified receptors within the vicinity of the site. Some assessors use an alternative
assessment where analytical models such as the Danneberg et al (1997) models are used
to predict concentrations and then insert them into probabilistic models to predict the
concurrence of these elevated concentration with worse metrological conditions (from the
wind rose data) and assess potential risks accordingly.
The subject bioaerosols risk assessment has not attempted to use any of the above
discussed commonly used methodologies and rather used the wind rose data for a
subjective assessment in isolation of any site specific data. The use of the wind rose data in
such a subjective manner is therefore not considered to be adequate to assess potential
impact from the site on the neighbouring properties.
We therefore have recommended the use of air dispersion modelling for the assessment of
potential impact from the site on the neighbouring sensitive receptors. We have discussed
the matter with Dr Martin McVay and he has expressed concerns regarding the applicability
of the use of air dispersion modelling stating that “I reiterated that our science projects are
still ongoing with regard to quantifying an appropriate source term and appropriate health
benchmarks for bioaerosols from composting sites, and that they will hopefully deliver
advice on the approach to take with regard to predictive risk assessments in the next year or
so. At present, where the source term uncertainty is far greater than the differences
between dispersion models, the benefits of using an advanced dispersion model over a
simple screening method like H1 are small”.
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We agreed with Dr McVay that the source term is essential information that is required for
any type of risk assessment for any site with emission that have the potential to pose
unacceptable risks to those reside in its vicinity. We however believe that identifying the
source term is the responsibility and duty of the operator.
Considering that ill health
complaints have been already reported, we see the necessity to undertake a proper risk
assessment. If the operator does not accept the dispersion modelling as an approach to the
risk assessment due to the lack of information on his operations, we suggest that he
propose an alternative assessment approach that demonstrates that the site is not
contributing to the ill health of the residents of the area. Potential nuisance from exposure
to odour from the operations will still require proper assessment following the EA guidance.
We have also highlighted to Dr McVay that a number of studies were conducted to identify
the source term for different types of composting facilities. These include an EA study that
monitored different source terms at different composting facilities with different types of
waste input. There is also a literature review undertaken by the HSE within which a large
data set regarding emissions from variety of composting facilities was presented. Recently,
a project report was published by Viridor and SWICEB. This report presents emission data
from variety of sources from operational areas on different sites receiving different types of
wastes. We recommend that in the absence of site specific data, literature values for
potential ranges of emissions for the different types of operations are collected, statistically
presented if possible and used as appropriate with attention given to the uncertainty in the
use of non-site specific data. This kind of assessment, though not accurate will at least give
an indication on the potential risk.
References
1
Environment Agency. 2003. Monitoring of particulate Matter in Ambient Air around Waste
Facilities, Technical Guidance Document, R&D project P1-441.
2
Environment Agency. 2001. Agency Position on Composting and Health Effects.
3
Environment Agency, 2001. Health Effects of composting, A study of three compost sites
and review of past data, R&D Technical Report P1-15/TR. ISBN 1 85705 680 9.
4
Environment Agency, 2001. Monitoring the Environmental Impact of Waste Composting
Plants, R&D Technical Report TR P428. ISBN 1 85705 683 3.
5
Environment Agency. 2001. Technical guidance on composting operations (version 3).
Draft for external consultation.
6
Health & Safety Executive, 2003. Occupational and environmental exposure to bioaerosols
from composts and potential health effects- A critical review of published data. Research
report 130 prepared by the Composting Association and health and safety laboratory for the
HSE.
7
Danneberg G, Grueneklee E, Seitz M, Hartung J and Driesel A J Microbial and endotoxin
immissions in the neighborhood of a composting plant Annals of Agricultural and
Environmental Medicine 1997; 4, 169-173.
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Literature referenced in the above documents
Gilbert, E. J., Ward, C. W. Standardised Protocol for the Sampling and Enumeration of
Airborne Microorganisms at Composting Facilities. 1999. The Composting Association,
Coventry
Lacey J, 1981 The aerobiology of condial fungi. In the biology of condial fungi, Eds. Cole
GT and Kendrick WB, Academic press, New york, USA 373-416
Lacey J, Williamson, P. A. M King P and Bardos, RP, 1990 Airbourne microorganisms
associated with domestic waste composting, Waren Spring Laboratory Report LR 808.
Lacey J, Dutkiewicz J . Bioaerosols and occupational lung disease J. Aerosol Sci. 1994, 25,
1371-1404
Lacey, J., Williamson, P. A. M. Airborne Microorganisms Associated with RDF Fines at
Castle Bromwich, CWM/110/93, Report to UK Department of the Environment Wastes
Technical Division, 1995.
Lacey, J., Williamson, P. A. M., Crook, B. Microbial emissions from composts and
associated risks In Aerobiology (Muilenberg, M. and Burge, H., eds.), 1996, 1-17, CRC
Press, Boca Raton, Florida
Malmberg P, Rask-Anderson A, Palmgren U, Hoglund S, Kolmodin-Hedman B and
Guernsey J R, 1988 Incidence of organic dust toxic syndrome and allergic alveolitis in
Swedish farmers. International Archives Allergy Applied Immunology, 87,47-53
Malmros P. Problems with the working environment in solid waste treatment. The National
Labour Inspectorate of Denmark report 1990.
Millner P D, Bassett D A and Marsh P B. Dispersal of Aspergillus fumigatus from sewage
sludge compost piles subjected to mechanical agitation in open air. Applied and
Environmental Microbiology 1980: 39, 1000-1009
Millner, P. D., Olenchock, S. A., Epstein, E., Rylander, R., Haines, J., Walker, J., Ooi, B. L.,
Horne, E., Maritato, M. Bioaerosols Associated with Composting Facilities Compost Science
and Utilization 1994, 2, 6-57
Haas DU, Reinthaler FF, Wust G, Skofitsch G, Degenkolb T, Schumann P, Marth E.
Emission of thermophilic actinomycetes in composting facilities, their immediate
surroundings and in an urban area. Centr. Eur. J. Publ. Health 1999; 2: 94-99.
Lavoie J, Alie R. Determining the characteristics to be considered from a worker health and
safety standpoint in household waste sorting and composting plants. Ann Agric Environ
Med, 1997, 4, 123 - 128.
Palchak R B, Cohen R and Jaugstetter J. 1990 A threshold for airborne endotoxin
associated with industrial scale production of proteins in Gram-negative bacteria.
Developments in Industrial Microbiology, 31, 199-203
Rylander R, Lundholm M and Clark C S, 1983 Exposure to arosols of micro-organisms and
toxins during handling of sewage sludge. In Wallis P M and Lehmann D L (eds) Biological
health risks of sludge disposal to land in cold climate.
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Rylander R, 1986 Lung diseases caused by organic dusts in the farm environment.
American Journal of Industrial Medicine, 10, 221-227
Rylander R. Organic Dusts and Lung Disease: The Role of Inflammation Ann. Agric.
Environ. Med.1994, 1, 7-10.
Rylander R. Evaluations of the risks in endotoxin exposures Int. J. Occ. Environ. Health.
1997, 3, S32-S36.
Rylander R, Bake B, Fischer JJ, Helander IM. Pulmonary function and symptoms after
inhalation of endotoxin Am. Rev. Resp. Dis. 1989, 140, 981-986.
Sigsgaard T, Back B and Malmros P, 1990 Respiratory impairment among workers in a
garbage handling plant. American Journal of Industrial Medicine, 17, 92-93.
Sigsgaard T, Malmros P, Nersting L, Pedersen C. Work related symptoms and lung function
among Danish refuse workers. Am. Rev. Respir. Dis. 1994, 149, 1407-1412.
Sigsgaard T, Hansen JC, Malmros P. Biomonitoring and work related symptoms among
garbage handling workers Ann. Agric. Environ. Med. 1997, 4, 107-112.
Tolvalen O, Veijanen A, Villberg K. Occupational hygiene in biowaste composting. Waste
Management and Research, 1998, 16, 525 - 540.
Tuomela, M., Vikman, M., Hatakka, A., Itävaara, M. Biodegradation of Lignin in a Compost
Environment: A Review Bioresource Technology 2000, 72, 169-183
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Appendix B
Map of Houses Within 250m
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Appendix C
Number of Houses Within 250m of Compost Farm
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Number of houses within 250m of compost farm
Dwellings within 250 metres of the composting pad. (Taking measurement to
boundary of dwelling not the actual dwelling.)
1.
2.
3.
4.
5.
6/7.
8.
9.
10.
11.
Old Sodbury Primary School
School House
Sunnymeade
19 Church Lane
17 Church Lane
15 Church Lane (Includes dwelling of a family of 4 and a business which
employs 5 South Glos residents.)
22 Church Lane: The Gate House
20 Church Lane: The Cottage
Weylode
Plough Farm (Home and an operational farm)
Additional properties within 250 metres of the composting operation itself.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25
26.
27
28
29
30
31
32
33
34
35
36
37
38
Oxleaze
Hayes Farm Cottage
The Coach House
25 Church Lane
23 Church Lane
21 Church Lane
13 Church Lane
11 Church Lane
Woodbridge (18 Church Lane)
16 Upper Church Lane
16 Lower Church Lane
14 Church Lane
12 Church Lane
10 Church Lane
8 Church Lane
6 Church Lane
4 Church Lane
2 Church Lane
9 Church Lane
7 Church Lane
5 Church Lane
3 Church Lane
1 Church Lane (Raisdale)
Vale View
Hill Crest
Next door to Hill Crest (name of property unknown)
Southcroft Farm
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Appendix D
CV – Ahlim Hashm
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Name:
Ahlim Hashm
Office:
Chepstow
Position in Company:
Principal Consultant
Qualifications / Memberships:
PhD Environmental Geotechnics, BEng Engineering,
B.Sc. soil sciences, The Lloyds prize, The David Lenczner prize,
The John Barrett prize and The Norman Thomas design prize.
Date of Birth:
22nd March 1962
Key Clients:
Worcester County Council
Gleeson Group
Simsmetal
Furlong Homes
Aylsford Newsprint Limited
Alcan,
St James Homes
Waste Recycling Group
Federal Mogul
NPL Estates
Areas of Expertise:
Ahlim has over 10 years experience working in environmental assessment and waste management
particularly human health, air quality and waste assessment. Specialist technical expertise in
modelling exposure, transport, retention and migration of contaminants in soil, water and air.
Extensive experience in the use of the more prominent protocols and software packages for
assessing risks to human health and the environment.
Experience Includes:
Ahlim is a human health risk assessment, air quality and waste management specialist responsible
for the human health risk assessment and air quality team. She has extensive experience in
environmental assessment and project management gained through working in the public and
private sectors. Prior to joining RPS, Ahlim was the project manager of the ERDF-funded
programme “Regional Centre for the Treatment of Contaminated land” and the technical
supervisor of the ERDF funded project “Development of commercial software tools for assessment
of contaminated land” within Cardiff University
Ahlim has applied her expertise to the assessment of risks to human health from exposure to a
wide variety of naturally occurring and artificial toxins and carcinogens via a range of pathways and
for a variety of land use scenarios. She has been directly involved in the assessment of potential
risk and nuisance impacts from gaseous and odorous emissions and bioaerosols from a number of
waste management/treatment facilities on the local air quality. She used her extensive experience
in the classification of waste and development of waste acceptance procedure to a range of waste
streams generated by various industrial activities
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Key Experience
Human Health Risk Assessment

Has undertaken a large number of human health risk assessments for a wide variety of
sites ranging from small residential properties with naturally occurring or commonly
found determinands to complex industrial premises affected by a wide range of
contaminants.

She used a number of human health risk assessment models including, CLEA,
SNIFFER, RBCA, smartRisk, and other internationally recognised models and
databases such as the USEPA PRG on-line model. She has also developed a number
of non-standard risk assessments for “special case” sites.

Within the context of the latest UK guidance on human health risk assessment that
requires the derivation of guideline values for chemicals of potential impact on human
health, Ahlim is the leader of the team responsible for deriving guideline values from
first principles. This involves extensive reviews of toxicological data for a large number
of chemical substances, evaluating the data to derive tolerable intakes and index
doses, identify all potential routes of exposure and utilise the derived values in
assessing risks from human exposure to these substances through relevant pathways
of exposure.
Air Quality Assessment
Carried out a number of tier 1 air quality assessment in accordance with the IPPC
horizontal guidance and the screening method for emissions to air from landfill sites
provided by the Air Quality Modelling and Assessment Unit of the Environment Agency for
a number of waste management/treatment facilities. As part of her responsibility as the
leader for the air quality team, Ahlim was responsible for the development of the in-house
package of the tier 1 assessment based on the regulatory guidance.
Carried out a number of detailed air dispersion modelling for a variety of waste
treatments/disposal installations such as gasification/pyrolysis and MBT plants, engines
and flares using the new generation dispersion model Aermod.
Carried out aerosol and odour assessments for a number of composting facilities using air
dispersion models. Ahlim has also involved in providing technical advice in respect of
identifying the location and height of the venting sources giving considerations to the local
meteorological regime and the location of sensitive receptors.
Landfill Gas Assessment

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Carried out landfill gas assessment as part of the PPC permit application for a number
of landfills accepting various waste streams using GasSim. Considerations were given
in all of these assessments to accidents and failure scenarios in order to quantify the
impact of given events and assess the reliability of landfill gas control system and site
engineering. She also involved in the development of the gas management plan for
these sites.

Annually produced and electronically submitted Pollution Inventory Forms for a large
number of landfills.

Involved in advising landfill operators on the sizing of flares of engines based on the
waste input and predicted methane emissions
Waste Assessment

Undertaken a waste classification based on the Hazardous Waste Directive and the
Environment Agency guidance WM2 and in accordance with the revised European
Waste Catalogue for a number of waste streams to identify appropriate type of
treatment and disposal options.

Developed a number of waste acceptance procedures in compliance with the
requirement of the Landfill Regulations (England and Wales) 2002 and amendments
2004 for a number of landfills. Ahlim has also involved in giving technical advice with
regards to the specific acceptance criteria as per the European Council relevant
Directives and Decisions for underground Storage disposal facilities
Other Experience
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
Carried out a number of risk assessment and ventilation requirements for the ingress
of methane and other gases from the ground into buildings. The assessments are
carried out in accordance with the CIRIA 152 methodology and various BRE
Publications. The ventilation requirements are estimated in accordance with the British
standard ventilation principles and other methodologies such as the Johnson Attinger
model.

Undertaken a number of ecotoxicological assessments for a number of sites of
ecological significance. Ahlim previous experience in research and modelling within the
field of fate and transport of contaminants gave her the ability to undertake site specific,
non-conventional risk assessment where required and in the absence of UK standards
and guideline values.

Managed a number of large-scale projects involved the design and management of
site investigation, risk assessment and remediation for a variety of industrial and waste
management sites. These include site specific risk assessment to controlled water and
sensitive ecological receptors from contamination in soil, water and air. This involved
the use of a number of models such as Consim, R&D 20, RBCA and bioplume.

Prepared a number of occupational health and safety strategies for remediation and
construction workers on heavily contaminated sites.

Undertaken site auditing and environmental due diligence for a large number of sites in
the UK on behalf of Lloyds TSB and other clients.
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