Plastic contamination is inescapable. Plastic micro-and nanoparticles — as well as the chemical compounds used to produce the polymers — are ubiquitous in the environment and present formidable confounding factors that make it impossible to establish causal relationships between a single chemical and measured human health outcomes.
Well-designed scientific studies involve a “before and after” protocol. This means that an experimental is first run, and specific outcomes are measured in the “before” state.
Following that only one single variable is changed (such as adding or deleting a single chemical), and the experiment is run again. If there is a change in any of the measured outcomes, then a valid conclusion can be drawn that the change in that single chemical is the casuse.
However, humans exist in a vast, uncontrollable, constantly changeable, and mostly unknowable matrix of different plastic-based and other chemicals.
Those chemicals exist in, and are mostly inseparable from:
- the air,
- non-stick coatings,
- surroundings (floors, walls, draperies, fabric coverings etc.),
- polymer gloves,
- thermal cash register receipts and
- an unknowable number of other sources.
What’s more, the consistency of those contaminants change over time and place and will vary from person to person.
Given the vast nature of confounding factors, it is not surprising that dietary intervention studies studying the effects of Bisphenol A (BPA) are inconsistent, not replicable and, on the whole, incapable of supporting a causal relationship.
Without a valid, causal relationship, it is not possible for a clinician or other health professional to make fact-based recommendations to their patients and clients. Likewise, regulatory decisions based upon those are not based on solid science and subject to endless arguments among scientists.
A prime example is the regulatory and scientific chaos regarding the human health effects of BPA that can be seen in the inconsistent findings in the U.S. Government’s CLARITY program which has failed to bring clarity to the issue:
- New CLARITY study draft of BPA safety is substandard science & repeats previous fatal errors
- Low-Dose BPA Paper in Toxicological Sciences Fatally Flawed & Must Be Retracted. Also Raises Doubts About Integrity Of Federal Lab Animal Facility
This chaos exists because neither plastic industry supporters of that federal study nor independent scientists who oppose it can offer human health effects data that rise above the confounding factors.
Dietary intervention studies are about a lot more than dietary interventions
Previous published dietary intervention studies provide catered meals that subjects eat in their home or work environment. Not only are the meals imprecisely prepared, but there are no controls if the subjects consume non-study food or drink.
Compliance to the protocol is not enforcable. This situation is even more critical in studies where participants are asked to recall what they have eaten and imbibed.
Even with perfect compliance by subjects to the dietary requirements, h0me and work environments also vary widely in air quality. PM2.5 levels, in particular, can dramatically effect inflammation and other health measures. The same holds for plastics from flooring, counter surfaces, synthetic fibers in clothing, furniture upholstering, bedding, foam mattresses and pillows.
Obviously all of those factors are further confounded by the variety of different and uncontrolled environments encountered in everyday life: commuting, shopping, and work environments which are rich in plastic contaminants including printer toner, roller chairs and mats, coffeemakers with plastic parts etc.
What factors need to be considered?
Within the bounds of the possible, a proper dormitory environment will will minimize confounding factors by providing the same environment — air, water, food — for all study participants.
- Minimize the use of, and contact with plastic.
- Towels, napkins and all other cloth material will be 100% cotton.
- All cotton fabric will be sourced from that which is grown organically, without pesticides. All items will be laboratory tested for pesticide and plastic residues.
- Bedding will be 100% cotton. Multiple layers will be installed to minimize migration of plastic from sanitary mattress covers which are expected to block migration from mattress materials.
- Subjects will be provided with a choice of all-cotton under-garments (possibly scrubs).
- All cotton outerwear will be provided. All garments will be pre-washed multiple (TBD) times to reduce/remove sizing or possible plastics contamination.
- All garments will be changed daily.
- Study-issued socks and slippers will be issued. Exercise shoes and cotton socks to be allowed in the ventilated exercise area only. Shoes must not be worn outside that area.
- Rooms will be identically equipped and all surfaces cleaned with an acceptable detergent and implements.
- If dormitory flooring is vinyl or polymer based, all chair legs will be covered with a sock-like cotton covering to reduce microplastic contamination. No chairs with rolling wheels will be permitted.
- Air monitoring for PM 2.5
- New HVAC air filters will be installed.
- Portable HEPA air filters will be employed. Number TBD
- Access to the dormitory will be restricted to study-related personnel
- Tub bathing will be allowed every 2 days.
- No showers will be allowed due to aerosolization of plastic chemicals and nanoparticles.
- Opportunities for exercise must be investigated, but remain problematic because of the use of plastics in exercise equipment. This may be possible by the use of proper ventilation to remove plastic contamination from leaching and frictional shedding of micro/nanoplastics.
- Psychological factors must be considered and resolved including need for privacy, minimum stress (to reduce cortisol levels), possible conflicts among study participants.
- This will be particularly important for sleeping arrangements unless it’s possible to provide a private room for each participant. Creative partitioning in multiple-occupant rooms might provide a solution.
- In addition to other screening requirements for potential participants, should study subjects be screened psychologically for their suitability to comply with the protocol and to interface appropriately with other subjects.
- Broadband internet access