The trend in the production of NPs is likely to lead to increasing amounts of nano-powders in the air, water and soil, which will consequently affect living organisms. Labielle et al. demonstrated that 25 % of Al(OH)₃-coated TiO₂ particles from sunscreens are dispersed as a stable colloid and become available to microorganisms and filter-feeders, while the remaining 75 % are probably incorporated into geogenic sediments, where they could become available to benthic fauna. Solar UV iradiation may penetrate as far as 20 m in the water column  and therefore photo-activate the dispersed particles, which may have an adverse effect on various aquatic organisms.

CSPI’s Chemical Cuisine is the web’s definitive rating of the chemicals used to preserve foods and affect their taste, texture, or appearance. Besides titanium dioxide, the group recommends avoiding artificial sweeteners like aspartame, acesulfame potassium, and sucralose, as well as synthetic food dyes like Yellow 5 and Red 3. CSPI and others have recently asked the Food and Drug Administration to ban the latter dye in foods and ingested drugs because the FDA has already determined that it is a carcinogen unsafe for use in cosmetics.

From studies deemed relevant, the experts found that titanium dioxide as a food additive is poorly absorbed by the gastrointestinal tract of mice and rats, with no adverse effects observed in short-term studies in rodents receiving titanium dioxide in their diets. No observed adverse effect levels (NOAELs) of 15,000 milligrams per kilogram of bodyweight (mg/kg BW) per day and 5,000 mg/kg BW per day—the highest doses tested—were established for mice and rats, respectively.