Mould Sampling Please contact us with your requirements.
Mould Sampling and Investigation Mould sampling and investigation may be required for any of the following reasons but is rarely required or recommended when visible mould is present:
Where water damage has not been remediated promptly and hidden areas such as ceiling, wall or floor cavities may have been wet for some time. The new British Standard PAS 64 identifies increased bio amplification and risk of mould after materials wet for 48 hours or more. Where mould odour is present but there are no visible signs of mould or where several suspect areas may be involved. Where health issues cannot be explained and are those possibly associated with mould or water damage contaminates. Buildings with environmental conditions conducive to biological activity, typically following flooding or long term water damage. Where Local Authority Environmental Health Officers have no evidence of visible mould and cannot assess hazards under the Housing Health and Safety Rating System and where although mould is recognised as a Cat 1 hazard they require scientific evidence to substantiate action. Where litigation against contractors, builders and landlords is considered and supportive evidence is required to substantiate a claim for decontamination and or replacement. To verify contractors decontamination and provide independent clearance following mould removal or decontamination. If you have a doctor who understands mould symptoms and treatment and requires specific tests to assess the presence of certain chemicals and or toxins which you may be exposed to.
The occupants of this flat had building related illness. Building Forensics undertook a standard investigation and identified major construction and design defect.
Be careful what type of mould sampling you buy or are provided with.
1 SWABS
Photo 1 shows swab sampling. This requires an awful lot of luck and great expense to be successful. First of all you have to be lucky if you capture the landing place of the spore, secondly you have to be lucky if the spore or fragment will travel in the air pathways to your sampling location. The WHO states this type of sampling has serious limitations
2 Culture Agar plates
Photo 2 shows agar plates with different types of growth. Of course the cheapest sampling cost is for CFUs or colony forming units, but this information is useless. Who cares how many spores are growing, we need to know the genus and species. Next we have to be lucky if the spore will grow or be overgrown by faster growing moulds. Then you have to be lucky if the spore likes the gar you prepared because there are several types of agar specifically designed for different tasks. The most important issues is that dead and dormant mould and fragments of spore case and mycelia simply cant grow but they are the major health hazard, but you wont identify them here.
3 Mycometer
Photo 3 This equipment is used by many unqualified investigators in the UK. It provides a very pretty and believable report which has absolutely no recognised worth and doesn't comply with any recognisable standards. It provides a number which is absolutely worthless and interpreted as spore numbers but cannot distinguish between genus or species. The significance here is that a high naturally occurring mould could be relatively safe while low levels of toxic mould which is usually below detection levels in outside air could be extremely hazardous and get a green flag. The technicians that use and promote this service often state it was approved by Environmental Protection Agency (USA) but they never approved it although they did test the equipment and stated it had limited qualitative use. Cannot provide useful information other than the presence of mould which is always naturally present anyway. The major use of mould sampling is to identify the species which often cause negative health impact, and I have seen countless Mycometer reports which give a green flag for low but extremely toxic mould cocktails
4 ERMI
In this sampling protocol samples are collected in a specified manner and analysed. The result is an ERMI score. The ERMI score is the average spore and species calculated in 1000 homes in USA . While a breakthrough in assessing average home contamination, several flaws exist. The homes assessed were in USA and construction environmental differences exist, and even though it may produce a report which shows you at a lower than 25 % of affected homes, your personal exposure levels and immune response may be in the top 100%.
5 Total Spore Counts
In this test samples are taken which can be used to assess the levels and presence of live, dead and dormant spores. This test can provide an indicator of mould presence especially when the growth is hidden. As with all sampling protocols this methodology has its drawbacks but is according to WHO a reasonable first step in assessing risk and hazard. Its importance is that it identifies both viable and non-viable spores both of which are health hazards which cannot be identified by culture based sampling. In the table below three separate samples were analysed and this includes ambient which is used as a comparison for genus levels. In our basic survey we include a minimum of 4 samples but accuracy is increased with sampling frequency
6 PCR-DNA sampling and analysis
This lab report shows the lab analysis of samples taken and provides spore counts and speciation. This type of report is of great interest to the medical profession who can recognise the more toxic species and perhaps treat accordingly. The major benefit in this technology is that fragments, mycelia and all spores are identified and of course the fragments are the highest risk to health
Other Tests to Asses Indoor Air Quality Apart from mould sampling there are many other tests to assess Indoor Air Quality (IAQ) and these include the following:
Dust Mite German Cockroach Rodents Cat and Dog Allergen Ozone Levels Carbon Monoxide Carbon Dioxide Formaldehyde Total Volatile Organic Compounds (VOCs) (chemicals in the air) Specific VOCs and their levels Glucans and Endotoxins (parts of spore case) Type of Sampling End Result Benefit / Shortfall Culture based Limited identification of some moulds present. Can provide genus and speciation. Does not identify non-viable and/or capture or cultivate many moulds present. Identified by WHO as having serious limitation. Expensive and takes approximately 6 days. Total Spore Counts Provides up to 100 times more accuracy than culture based. Identifies both viable and non-viable spores. Conforms to British Standards and WHO recommendations. Identifies genus but not all species. Low cost 24 hour results plus transport. PCR-DNA Complete identification of genus/species of viable and non-viable spores, mycelium and fragments. State of art. Slightly more expensive than culture based and takes about 7 working days although can be next day premium rate. Infra-Red Gas Chromatography Moulds release various chemicals (VOCs) in their growth process and these can be detected in buildings before visible growth appears. Results are relatively accurate and can provide very useful analysis in terms of Indoor Air Quality. Similar costs to PCR NAHA Enzyme based on site quantitative analysis. This process samples airborne mould contamination and provides a total level of contamination although not genus and or species. Although quantitative it is a comparison against know or ambient comparison levels.
Once the type of sampling results are identified the protocol is chosen from the table below:
Sampling Technique Method / Result Culture Based Air sampling SAS or Anderson single stage various agars to suit different moulds and bacteria Swab Qualitative test only to identify species present in area swabbed. Results may vary due to growth and agar issues Total Spore Counts Tape lift Collects sample on scotch tape affixed to microscope slide. Provides analyses of visible growth Air sampling Samples collected in filter cassette for direct microscopy Infra-red GC Extended air sampling through purpose made desorption tubes NAHA Air sampling thorough special cassettes and on site lab process PCR -DNA Special cassette extended sampling period 2 hours
More information on the two most common types of mould sampling: 1. Culture Culture type sampling a is known to provide very limited results as many spores may not carry in the air due to aerodynamics, they may not accept the culture media as a suitable growth food. Often the active growth of some moulds will overpower the slower growing moulds and therefore a complete range of some moulds may be missed. The World Health Organisation stated in 2009 that this type of sampling is generally unsuitable for investigation purposes, preferring total spores counts and PCR-DNA.
2. Total Spore Count (Air Sample) a. Total Fungal Spores
According to ACGIH, "differences that can detected with manageable sample sizes are likely to be in 10-fold multiplicative steps (e.g. 100 versus 1000)". Following this logic, if total fungal spores are ten (10) times greater in the sample from a suspect area than in the negative control sample collected from a non-suspect area, then that sample area may be a fungal amplification site.
b. Mycelial Fragments
Mycelium is a fungal mass that constitutes the vegetative or living body of a fungus. Following the same logic above, if total mycelial fragments are ten (10) times greater in the suspect sample than in the negative control, then the sample area is considered to be a fungal amplification site. The presence of mycelial fragments provides evidence of microbial growth.
c. Mycotoxins
Moulds can produce toxic substances called mycotoxins. More tha n 200 mycotoxins have been identified from common moulds, and many more remain to be identified. Some of the molds that are known to produce mycotoxins are commonly found in moisture-damaged buildings. Exposure pathways for mycotoxins can include inhalation, ingestion, or skin contact. Although some mycotoxins are well known to affect humans and have been shown to be responsible for human health effects, for many mycotoxins, little information is available, and in some cases research is ongoing. Some molds can produce several toxins, and some moulds produce mycotoxins only under certain environmental conditions. The presence of mould in a building does not necessarily mean that mycotoxins are present or that they are present in large quantities.
d. Water Indicator Moulds
Certain authorities identify certain moulds whose presence indicates excessive moisture. The presence of a few spores of indicator mould should be interpreted with caution. Additionally, it should be recognized that these named moulds are not necessarily the only ones of potential significance.
