9/26/11

Toxic Water Bottles

               In the last decade, there has been rapidly growing public concern surrounding the use of certain types of plastic water bottles due to the discovery that some plastics leach potentially harmful chemicals.  Most notably, bisphenol A (BPA) and phthalates have been shown to leach from polycarbonate as well as other plastics and in turn contaminate beverages.  In animal studies, both compounds have produced reproductive health problems.  What’s more, BPA is a known endocrine disruptor and can therefore interfere with metabolic and developmental processes.  That said, all of the negative attention on plastic bottles and their associated toxicants seems to have generated unnecessary confusion in the public as it relates to discerning which plastics are toxic and which are safe.  Below, I have composed a list to reduce this confusion.  By simply looking at the recycling code on plastic products, this list will enable you to determine whether a plastic is safe.

  

........................................ Not known to contain BPA or phthalates, but contains antimony (a possible carcinogen*)     
     
   
........................................ Not known to contain BPA or phthalate 
........................................ May contain phthalates

        
........................................ Not known to contain BPA or phthalates

            
........................................ Not known to contain BPA or phthalates

 
........................................ Not known to contain BPA or phthalates
  

......................................... Contains BPA

            Note from the above list that Code 1 plastics contain a possible carcinogen (a carcinogen is a substance that causes cancer).  Code 1 plastics are generally used to manufacture single-use water bottles, peanut butter jars, mouthwash bottles, etc., and are characterized by their clear, smooth, flexible design.  With respect to Code 1 water bottles, because they can release antimony and other chemicals from their plastic, experts do not recommend using them for repeated use.  In fact, washing them can abrade the plastic and in turn lead to the release of more chemicals.  In general, if you’d like a bottle to reuse for drinking, which I recommend since it’s both healthier and cheaper, it’s best to abandon plastic all together.  I drink from a stainless steel bottle.  These bottles have become quite popular and are now sold almost everywhere!
            Code 7 plastics are shown in the picture above.  These polycarbonate plastics are characterized by their clear, hard, shatterproof design and are often used to make reusable water bottles.  While BPA-free bottles are now widely available, I personally remain skeptical of code 7 plastics as it is unclear as to what chemical has replaced BPA in the manufacturing process and to what extent this chemical might cause other health problems.

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                                                                                    -Shahir Masri






9/19/11

Vaccines and Autism

      

           The primary source of ethyl mercury, and the source which has gained the most attention as it relates to this chemicals role in public health, is through vaccinations.  For a number of decades, a compound known as Thimerosal has been used as a preservative in numerous types of vaccines.  It is this preservative which contains the ethyl mercury ion and is in turn the source through which most people, in particular children, are exposed. 
            The reason for incorporating a preservative into vaccine formulas in the first place is to prevent microbial growth in the event that a vaccine is to become contaminated; usually through repeated puncture of multi-dose vials.  Though Thimerosal has been used in various biological products, including vaccines, since the 1930’s, it was not until 1968 that the requirement for using such preservatives in multi-dose vaccines was officially incorporated into the United States Code of Federal Regulation.  In recent years, however, the U.S. has taken many steps in transitioning to Thimerosol-free vaccines; sometimes switching to single-dose vials that do not require preservatives (A single-dose vial refers to a vial which is good for administering only a single dose of vaccine.  Since a single-dose vial is not repeatedly punctured for multiple uses, there is virtually no likelihood for contamination and therefore no need for a preservative to kill pathogens).  Most countries, however, have yet to make this transition. 
            What is likely of greatest concern to many families as it relates to ethyl mercury exposure, due in great part to the media attention it has received, is the association between childhood vaccines and autism; specifically, those vaccines administered to prevent measles, mumps, and rubella (MMR) diseases.  This association, however, is still dubious at best.  In fact, when the Institute of Medicine formed an Immunization Safety Review Committee to investigate this link several years back, the committee concluded that the data did not support any such link between vaccinations and autism.  Now this cannot guarantee that vaccinations have no relation to autism as there is always the possibility in science that a study may simply have failed to pick up on given association. Given the best available evidence to date, however, there is no reason to believe that vaccines are linked with autism. That said, fearing to approve your child’s vaccination is not justified by the weight of research on this topic. The likely reason parents attribute their child’s autism to vaccines in the first place is due to a coincidence that autism becomes detectable at about 2 years of age (when deficiencies in a child's speech are first apparent), the same time when children receive MMR vaccines.
            Regarding this topic, it is worth noting that measles, mumps, and rubella were three previously devastating diseases which have now been controlled in many places thanks to their vaccines (preventing thousands of deaths in the United States alone!). Furthermore, the importance of Thimerosal in such vaccines is also worth noting as there have been numerous instances of children dying within days of receiving unpreserved vaccinations later found to be contaminated with living bacteria.  In short, neither vaccines nor Thimerosal should be discredited as both substances have played critical roles in saving lives.  If you are still inclined to avoid this preservative, however, there are a couple of options you have which do not require avoiding vaccinations altogether.

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                                                                                                    -Shahir F. Masri

9/15/11

Pesticides: Natural vs. Synthetic

       

         Pesticides can be both synthetic as well as natural in origin.  Also known as botanical pesticides, natural pesticides are those which plants have evolved as a defense to ward off threatening organisms.  As a result, such pesticides can have a variety of different sources in the environment, depending on the species of plants from which particular pesticides originate, and the prevalence of those plants in the environment.  Aside from in nature, natural pesticides are also formulated in factories and marketed to the public for use in home gardens, farms, etc.  Consequently, sources of such pesticides are crops or plants which either naturally produce or have been sprayed with these chemicals, including much of the produce which winds up in our local markets.
            While the term “natural” may have a positive ring, it is important to realize that natural does not mean harmless.  Rather, many natural and synthetic pesticides share a common goal; that is, to kill or otherwise incapacitate.  What’s more, while synthetic pesticides are usually designed to target specific organisms, botanicals are often broad-spectrum pesticides, killing both harmless and harmful species alike.  Having said that, natural pesticides generally breakdown quickly outdoors and therefore pose less of a threat in the environment over time.
            Synthetic pesticides are often natural pesticides which have been slightly modified by chemical processes in order to increase their toxicity and stability in the environment.  As with natural pesticides, sources of synthetic pesticides include much of the produce we eat as well as any other plants or crops which have been sprayed with such chemicals.  Due to the stability of synthetic pesticides, however, these chemicals can persist in the environment for extremely long periods of time.  As a consequence, these chemicals can contaminate water bodies, sediments, and soils, as well as work their way up the food chain, thus contaminating meat products.  Sources of synthetic pesticides are therefore much more widespread than those of natural pesticides.  Of the most notable sources as it relates to meat consumption are upper predatory marine species such as shark, swordfish, tilefish, and certain species of bass.

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                                                                                            -Shahir F. Masri