Effects Of Using Polycarbonated Plastics

In today's world ‘plastic' is the substance that is being widely used by people for their daily course. Be it from carrying things in a polythene bag or store grains in plastic containers or storing water in PET bottles etc. Also in this fast pace life the stored food with preservatives is consumed widely all over the world which is mainly preserved in metal cans.

But these cans and the PET bottles is a poison for the person who uses it.

Now the question arises how it is harmful to the humans?

Many transparent 'plastic' bottles are made from polycarbonate, usually a polymer of ‘Bisphenol A'.

In this paper, mainly the harmful effects of Bisphenol A in the human life are discussed.
 

First synthesized in 1891, the chemical has become a key building block of plastics from polycarbonate to polyester; in the U.S. alone more than 2.3 billion pounds (1.04 million metric tons) of the stuff is manufactured annually. Bisphenol A also known as BPA, is used in the preparation of the polycarbonate plastic and epoxy resins, both of which are used in a wide variety of applications that make our lives better and safer.

Polycarbonate Plastic Sheet

POLYCARBONATE: A transparent thermoplastic material

Also it is an industrial chemical that has been present in many hard plastic bottles and metal based food and beverage cans since 1960. 

The polycarbonate plastics made using BPA are used in many food and drink packaging applications while the epoxy resins are commonly used as lacquers to coat the metal cans or bottle caps or water supply pipes.    

Harmful effects:

According to the scientists of University of Cincinnati (UC), the temperature of the liquid has a great impact on how much BPA is released. It is found by Schott Belcher and his team when the polycarbonate drinking bottle is exposed to boiling hot water, the amount of BPA released 55 times more rapidly than before exposure to hot water.

In Feb 2008, Belcher stated that, "There is a very strong suspicion in the scientific community, however, that this chemical has harmful effects on humans, as little clinical evidence related to humans have been found."

In another research carried out in the same University by A research team lead by Scott Belcher, PhD, Hong Sheng Wang, PhD, and Jo El Schultz, PhD, in the department of pharmacology and cell biophysics, found that exposure to BPA and/or estrogen causes' abnormal activity in hearts of female rats and mice. BPA, an environmental pollutant with estrogen activity, is used to make hard, clear plastic and is common in many food product containers. It has been linked to neurological defects, diabetes and breast and prostate cancer.

Polycarbonate Plastic Roof Panels

Belcher and team found that the presence of BPA in the cells caused an increased the release of calcium from sarcoplasmic reticulum – the part of cardiac muscle that stores and release the calcium ions indicating spontaneous release that's likely causing irregular heart beats and may have other harmful actions, especially following heart attack.

In female cardiac muscle cells, the blocking or genetic removal of estrogen receptor beta completely blocked the contractile effects of BPA and estrogen, while in males, blockade of the effects of estrogen receptor alpha caused the male heart to become more 'female-like' and become responsive to estrogen and BPA.

These studies enable us to identify the major cardiac risks after a long term exposure to BPA for a woman's health.

The U.S. Centers for Disease Control (CDC) found that traces of BPA appeared at levels ranging from 33 to 80 nanograms (a nanogram is one billionth of a gram) per kilogram of body weight in any given day levels 1,000 times lower than the 50 micrograms (one millionth of a gram) per kilogram of bodyweight per day considered safe by the U.S. Environmental Protection Agency (EPA) and the European Union's (E.U.) European Food Safety Authority (EFSA).

BPA once ingested is broken down to glucuronide a waste product that is easily excreted. Yet CDC found glucuronide in most urine samples collected in 2004, suggesting constant exposure to it glucuronide in most urine samples, suggesting constant exposure to it.

Chemist Steven Hentges, executive director of the polycarbonate / BPA global group of the American Chemistry Council states that, ‘there is a constant low-level exposure to the chemical presumably in our diet.'

Fred vom Saal, a reproductive biologist at the University of Missouri–Columbia, warns that babies likely face the "highest exposure" in human populations, because both baby bottles and infant formula cans likely leach BPA and according to him, "In animal studies, the levels that cause harm happen at 10 times below what is common in the U.S."

Tim A. Osswald, an expert in polymer engineering at the University of Wisconsin–Madison stated that during the manufacturing process, not all BPA gets locked into chemical bonds. That residual BPA can work itself free, especially when the plastic is heated, whether it's a Nalgene bottle in the dishwasher, a food container in the microwave, or a test tube being sterilized in an autoclave.

Bisphenol A is a known endocrine-active chemical. Low-level human exposure is widespread due to the chemical's presence in polycarbonate plastic and epoxy resins, but understanding long-term consequences of exposure will be challenging. According to Frederick vom Saal, it is a fundamental part of endocrinology, and it is beautifully demonstrated, that stimulation at the cerebellar cell surface receptor is able to cause effects at doses below a part per trillion. Not only are the doses many magnitudes lower than those considered in classic high-dose toxicity studies, but at extremely low dose bisphenol A demonstrate a response that disappears as the dose increases. As the dose increases there is always an increase in response, and hence it is challenging to study the effects of bisphenol A.

Bisphenol A at Low Nanomolar Doses Confers Chemoresistance in Estrogen Receptor Alpha Positive and Negative Breast Cancer Cells

Effects at even low BPA exposure include prostate cancer, breast cancer, early puberty onset, alterations in gender-specific behavior, decreased sperm count, affects on fertility, behavioral effects including hyperactivity, increased aggressiveness, impaired learning and other changes in behavior, and other problems. And, astonishingly, BPA is found everywhere making human exposure widespread.

Precautions:

Baby bottles and sippy cups:

AVOID bottles such as Dr. Brown's, Avent, clear Evenflo, FirstYears, Platex VentAire, Sassy and TupperCare as they are all contain bisphenol A. On the sippy cup side, avoid Nuby cups with handles coming up from the bottom of the cup, Gerber Soft Starter, and Gerber Suzy's Zoo & Sippy Snacker.

BPA-free bottles and sippies flagged as safe include: glass bottles, Born-Free, Medela breast milk storage bottles (made with polypropylene) and disposable bottle systems that have polyethylene plastic inserts.

If you must use a bottle/sippy made with BPA, you should NEVER store milk in a container in it, as the chemical could leach into the milk.

You should also discard any bottles that are scratched, appear cloudy or generally have an altered appearance from their "new" look.

Exposing to heat, harsh detergents (no dishwashers) and microwaving can cause leaching

It's in the lining of canned foods, where it appears to be the most common way to be exposed. BPA can leach into the food inside the can.

It's especially important to note that infants fed canned formula are at the greatest risk.

Not all the plastic food containers are made up using BPA, but care should be taken while using them so that other chemicals do not leach into the food products.

There are 7 different types of plastics out of which type 1, 2, 4 and 5 are safe fro storing food while type 3, 6, and 7 are not, with 7 being BPA.

  

Conclusion:

It is also important to note that the studies that found the harmful effects were government funded. The industry-funded studies did not find any threat to humans, so if you embark on your own search on bisphenol A, please make sure to note if the study was industry-funded. They have a way of hiding things to protect their bottom line. Searching for and manufacturing safer alternatives can be costly.

Hence, from the above discussion it can be concluded that human exposure to bisphenol A is very less but is increasing rapidly.

Scientists are looking for microbial ways to degrade it to simpler compounds so that the harmful effects can be avoided.

Thus, always heat food in a microwave safe container, glass is best bearing the pain of washing an extra dish is better than that of chemotherapy. It's your choice of selecting the pain you want to bear.