We have had a waterbed for many years. Recently we have had a problem with a strong mold smell coming from the mattress. I wash and dry the bedding on hot, and clean the mattress with Clorox wipes and anti-bacterial spray. Within a couple of days the smell is back. It really irritates my allergies. What can this be from and what can I do? – Deb, NY
A: As a long-time owner of a water bed, I am quite aware of odor and other related problems associated with them. One of the most common is a sour microbial odor that seems to appear overnight. That is the odor of excessive bacterial growth inside the water mattress itself. In fact, manufacturers advise consumers that they should periodically (every year or so) add a biocide (available from bed and mattress retailers) to the water mattress to control microbial growth. These biocides usually work well in keeping bacteria under control. As these biocides become less effective with age, bacterial populations may increase enormously producing a very unpleasant odor. This odor may be controlled by adding another dose of biocide to the water to kill off the bacteria. However, in some cases, such repeated biocidal treatment may not be effective in eliminating the odor problem and the mattress will have to be replaced.
Water beds tend to have a problem with mold growth on mattress pads and other bedding. This is not uncommon since mattress heat and the imperviousness of the vinyl plastic mattress wall prevents the passage of water vapor emitted from human bodies. This increases sweating and moisture levels in pads and bedding. This moisture as well as human skin scales and non-synthetic bedding fabrics provides an excellent growth environment for a number of mold species. An examination of such bedding may reveal the presence of tiny round blackish spots which are in many cases mold colonies. Such bedding needs to be washed in warm water (≥ 120 degrees F) on a periodic basis. Such machine washing will typically prevent mold growth for a time and also wash away mold spores and fungal parts. It generally will not remove the stains produced by the mold types which have grown on it. Dry cleaning can be even more effective in killing mold on mattress pads and bedding, and may in some cases remove the tiny dark spots.
New waterbed mattresses also have a very distinctive non-microbial odor associated with them. It is the odor of chemicals that are being released from the vinyl material that forms the mattress exterior. The odoriferous chemicals are released from unreacted compounds used to produce the vinyl polymeric plastic. They can also be produced by the plasticizers that are incorporated into the vinyl plastic to keep it soft and pliable. These plasticizers are semi-volatile compounds and as a consequence they are released very slowly.
The most common plasticizers used in soft plastics belong to a group of compounds called phthalic acid esters. A number of research studies n Europe have showed significant associations between respiratory health problems (asthma, wheeze, bronchial obstruction, cough, phlegm production, rhinitis) and the quantity of plastic materials present in a building environment; others with the concentration of plasticizers (such as n-butyl benzyl phthalate and di-2-ethylhexyl phthalate) found in house dust. As such, sleeping directly on a plastic-based material such as a water bed mattress (even when covered with bedding) may pose a respiratory health risk to individuals sensitive to such compounds.
