Other problems exist with some plastics that are used for many disposables. Sometimes, the inert plastics themselves are not
as bad as the plasticizers and additives that are inserted into the plastic matrix. With others, their degradation products
may not be completely benign; polyvinyl chloride is a well-known example. Because of this, some plastics cannot be incinerated
and even slow degradation in landfills may result in the release of undesirable material. In these situations, the plastics
must be disposed of in a controlled manner, much in the way that laboratory solvents or infectious waste must be handled.
The proper disposal of these plastics with undesirable properties is often thwarted by uncaring or ignorant laboratory workers
who throw the item into the closest trash container rather than walk over to where the special trash container is located.
While it is difficult to prevent the actions of an uncaring worker, laboratory management must include a discussion of proper
disposal in its analyst training to at least minimize the effects of ignorance. When a laboratory introduces plastics that
have special disposal needs, it should also introduce proper training.
Laboratory management needs to consider proper-disposal requirements, as well as training, to determine whether costs outweigh
the advantage of using disposables. Often, laboratory management itself is ignorant of the need for special handling or disposal
of these plastics. Their problematic properties are not widely advertised, but manufacturers who introduce these products
into commerce should be responsible for informing the user community of the need for special procedures. This communication
could take an approach that is similar to the way pharmaceutical companies use direction inserts.
Another problem with disposables is especially prevalent in the QC laboratory, where a large number of small items are used,
ranging from pipette tips to small test tubes and Pasteur pipettes. When they are emptied, a relatively large volume of liquid
remains trapped within, either from capillary action or simple surface adhesion. This results in a considerable amount of
contaminating liquid often being present in the laboratories' trash receptacles. Novice analysts are taught to rinse reusable
items before placing them in containers for eventual washing; but this is not done with disposables. In many cases, no attempt
is made to empty the items before they are placed in trash containers.
Most laboratories have special procedures in place for collecting and isolating disposables that were exposed to radioactive
isotopes, but these laboratories may not have procedures for isolating items that may be contaminated with equally problematic
substances. Perchloric acid and halogenated hydrocarbons are often present in waste containers for disposables. In one laboratory,
acetonitrile (methyl cyanide) fumes were continuously present as they evaporated from vials and pipettes in waste containers.
Just because items are disposable, the contaminants that travel with them may not be. There are many solvents and reagents
used in the QC laboratory that are considered to be environmental toxins. Long-term familiarity may cause analysts to forget
about the dangers posed by these materials, and periodic reminders may be needed. Once again, laboratory management must be
aware of the properties of the material used in the laboratory.
Another issue with disposables is trust. Disposables were introduced by highly reputable manufacturers and distributors, which
led to an unquestioning trust in the properties of disposables. The problem now is that the effort to save on costs has driven
many reputable manufacturers and distributors to deal with suppliers who are not as reliable as might be desired. Many disposables
are now outsourced to organizations where the distributor has little or no control over the quality of operations.
In QC laboratories, there is an unquestioning faith that disposable pipettes and other disposable measuring equipment are
accurate, and that the manufacturer produces a highly uniform product from a process that produces an accurately marked item.
But this is not necessarily true. Sometimes, the actual producer lacks a reliable and accurate process.
Pipettes used in the microbiology laboratory or in the manufacture of sterile products are routinely cleaned and sterilized
by validated procedures with biological indicators included in the sterilization batch. When sterile pipettes are purchased,
however, they are not randomly sampled and tested for sterility. There have been sporadic reports of microbiology laboratories
where a sudden rash of positive test results has been obtained. If a laboratory should encounter a number of unexpected, positive,
sterility test results, it would seem sensible to test a random selection of the disposable, sterile pipettes that were used.
For that matter, how often have media fills failed because of the random presence of one or two contaminated pipettes that
were used to transfer samples or media?