Wei Tang, PhD – Microbial Sampling and Analysis & Sandy Recovery -One Year After

Air Date: 11-1-2013| Episode: 304

This week on IAQ Radio we are joined by New Jersey resident and founder of QLab, Dr. Wei Tang…

Full Description:

This week on IAQ Radio we are joined by New Jersey resident and founder of QLab, Dr. Wei Tang. Dr. Tang graduated from Cornell University with his Master and Ph.D. degrees in Soil Microbiology. He has conducted numerous research projects at the Cornell University Soil Microbiology Laboratory using microorganisms for bio-remediation of environmental organic pollutants. He  has also spent over 20 years at premier laboratories focused on microbiological sampling and analysis methods for indoor environmental quality assessment. He has taught professional development courses and presented frequently at national conferences on analysis of indoor microorganisms and also on various topics including investigation and remediation of microbial growth in indoor environments.


In addition to founding QLab Dr. Tang is the inventor of several advanced microbial sampling devices including AccuScience Triple Gel-Tape, Sweep-Swab and Sponge-Swab. He also developed several advanced analytical methods such as AccuScience High Performance Spore Count and AccuScience Triplicate Analysis. Dr. Tang currently serves on IAQA and IESO Board of Directors. He is also the IESO President and IAQA Trenton Chapter Director.

Z-Man’s Blog:

Weighing In

Dr. Wei Tang, PhD is the owner Q Lab, a boutique microbiology lab located in Metuchen, NJ which is focused on delivering high quality lab results to clients.

Post super storm Sandy:

· Restoration and remediation focus was on public and commercial building

· Many houses remain unrestored, 1 year later.

· Many homeowners lacked the necessary money and resources to properly restore their property. Money spent on emergency work and remediation wasted due to delayed structural drying.

· It is recommended that sand dunes be built to resist future storm surges, which will interfere with water views ocean front property.

· Under normal circumstances, fungal growth is visible 1-2 weeks after flooding. Following Sandy, it is theorized that as water evaporated, sea salt remains behind which inhibits fungal growth.

Qualifying Labs:

· “Labs can only analyze what has been collected.”

· Compare credentials of lab director.

· Compare credentials and training of analysts.

· ASTM standard for spore trap analysis is a good starting point.

Sample Collection:

· Opines that the recommended sampling area of 1” x 1” is too small and that a sampling area of 12” x 12” is needed to provide good data. 3 options are offered for analysis of samples: direct microscopy, 48 hour viable or 7 day culture.

· Multiple tape lifts from the same area often look different. Opines that IEPs should take 3 samples from the same area of exposure.

· Samples from unfinished side of drywall provide better information because they haven’t been cleaned.

· Advises that industrial strength optically clear tape be used for tape sampling.

· Tape lift slides lack the necessary flexibility and miss material lodged below surface in indentations.

· Standard tape lifting method leaves valuable material behind because sampling method misses indentations such as between grain on raw wood.

· Standard swabs push material around and leave important material behind.

· Some standard swabs incorporate nutrient media which can skew results. Recommends that samples should be sent to the lab sans buffer.

· Aggressive sampling, with pressure and in 4 directions yields superior samples.

· Advocates the use of gel swab for improved 3 dimensional sampling.

· Advocates the use of synthetic sweep swabs for improved collection.

· On bacteroides, “the DNA of a serial killer doesn’t kill you.” DNA doesn’t make us sick, DNA can be preserved for a long time.

· On ATP sampling. Like a home pregnancy test ATP screening is subject to false +/-, for a professional opinion see an OBGYN or use a lab to confirm results.

Post remediation verification:

· Antimicrobials and biocides can impact post remediation sampling results, that a post remediation verification criteria of < 1,000-10,000 spores per square inch is suitable for residential, noting that healthcare should be much lower. Superior cleaning costs money and should result in lower counts.

· Indoor reference sampling, remediated areas should reflect lower counts post remediation than are reflected in an unaffected area of the property that was not remediated.

· Cement floors should be analyzed post remediation.

· 100-200 CFUs per square inch of total bacteria are OK providing no E coli are detected (TSA media dilution).

· “It’s not what the swab collects; the important issue is what is left behind” “A better way to see the big picture.”

Dieterism: The weak links in sampling are the technician and mode of transport.

Today’s Music: “Jersey Strong” by After the Reign

Z-Man signing off