Harmful Effects of Low Quality PET Bottles

PET (Polyethylene terephthalate) plastic is made by polymerization of two chemical named ethylene glycol and terephthalic acid although there are some other routes also used for the manufacturing of PET. PET manufacturing required some other chemicals to get the desired properties of PET. Different types of catalysts (contains heavy metals, ions and radicals) are used in polymerization. These catalyst needs to be completely removed from the product which results in increase the cost of PET. Some traces of catalyst remain in it. Low quality PET is when manufacturer not removes these chemicals as per standards.

Low quality PET and Degradation

PET degrades if not carefully processed or with the passage of time and at high temperature. Acetaldehyde (AA) is a product in the result of degradation wich lowers the quality of PET bottles. Less than 10 ppm is allowed for bottles but during the process when temperature is high the level increase the upper limit and causes change in the taste of water.

Manufacturers often add different chemicals (Processing aids, Lubricants, colors, stabilizers, Nucleating agent etc.) to plastics to give them the exact characteristics they are looking for, like flexibility, strength, and reduced production cost. These components can include phthalates, bisphenol A (BPA), polybrominated diphenyl ethers (PBDE) and tetrabromobisphenol A (TBBPA) all of which alter hormone expression in nonhuman animals and humans. These chemicals present only in poor quality or contaminated PET, when other types of plastics get mixed (Table).

These chemicals are known as endocrine-disrupting compounds and each affects different elements of hormone disruption (e.g. inducing estrogen-like activity, thyroid hormone homeostasis disruption, anti-androgens, and so on).

Uses of PET

PET is typically used to hold soft drinks, water, juice, sports drinks, beer, mouthwash, ketchup, and salad dressing. They are also used as containers for peanut butter, jelly, jam, and pickles. This type is also used in oven-friendly film and microwavable food trays.

PET is considered to be safe, but there are some issues to be aware of.

The primary problem is that antimony, a metalloid element with toxic qualities, leaches from PET. The rate of leakage increases with temperature. Normally, the amount of antimony that seeps into liquid is well below the U.S. Environmental Protection Agency’s maximum contaminant level. But that assumes the container stays at room temperature.

Studies indicate that storage of these bottles at extended periods of time, and at increased temperatures, can result in unhealthy amounts of antimony. Study showed that microwaving can significantly increase the rate at which antimony leaches into PET bottles. The authors recommended that plastic bottle manufacturers wash bottles before first use to remove metal contaminants like antimony.

In 2012, a study indicated that, in addition to antimony, brominated compounds can also leach into PET bottles. Bromine, a naturally occurring element that is a liquid at room temperature, can irritate the skin, mucous membranes, and tissues. But it’s not clear from the study if the concentrations of leaked bromine are at dangerous levels.