The term "heavy metal" is a somewhat arbitrary and amorphous designation having no official chemical meaning. Nevertheless, the use of this term not only persists but is quite common. Some heavy metals are principal for life. Human blood is red, for example, because that is the color of the oxidized iron carried in our blood cells. A number of heavy metals toxic. Some heavy metals are principal at low concentrations but are toxic at higher concentrations. Copper is relatively toxic for humans, but is principal for most mollusks and some arthropods (such as the Horseshoe Crab) because the oxygen carrying highlight of their blood is not iron but copper. Oxygenated copper is a lovely shade of blue. Nonetheless, iron-based blood carries about four times as much oxygen as copper-based blood. Other still more primitive sea creatures such as sea cucumber have "blood" that is yellow, because it is based upon Vanadium, which is toxic for us, although this pigment does not carry oxygen for the organism. It is leading to reconsider life's history, diversity and attendant intricacies when assigning the toxicity of any given substance.
All heavy metals are "natural" components of this world we live in, but "natural" doesn't mean harmless. Just ask anything bitten by a venomous snake, scorpion, fire ant, or what have you. The same beautiful natural stream capable of providing an idyllic day of fly-fishing for trout is also able to give rise to the misery of black flies in their millions. To contemplate this for yourself (not recommended), take a hike straight through the backwoods of Maine in May.
The food we eat is unmistakably a natural product, even given the modifications introduced by breeding efforts complicated in its production. However, these days much of our food comes from our advanced agriculture and an ever-increasing fraction of it is imported. It is Fda's job to contemplate food advent into the U.S., yet Fda itself admits that it is able to contemplate only about 2.1% of this country's food imports. It is a big job, yet soon Fda may have fewer funds to work with. Fda is currently implementing the Fda Food protection Modernization Act passed in January of 2011, yet in March 2012 House allocation Chairman Paul Ryan (R-Wi) outlined a allocation that would cut an additional .3 trillion from health and Human Services throughout the next decade over and above President Obama's allocation request. Fda is part of health and Human Services. House Agriculture Committee Chairman Representative Frank Lucas (R-Ok) praised this allocation proposal as evidence of Republican leadership in deficit reduction. It seems very hard to avoid the conclusion that House Republicans would prefer to see deficit reduction even at the cost of food safety. This is especially worrisome as food protection over the past year has been far from ideal.
Fda Commissioner Margaret Hamburg has already warned that foodborne outbreaks and problems with import inspection will increase if Fda finds itself underfunded. She pointed out that Fda activities currently cost each American consumer about three and a half dollars per year. In addition, Fda has indicated its pessimism regarding future funding by proposing to charge food facilities a registration fee to pay for the needed oversight. Such pessimism may well stem from the fact this proposal for alternative funding was rejected by yet other House Republican, Representative Tom Latham (R-Ia). Representative Latham's position was that such a registration fee would come to be just a tax on the consumer. What about the import of his actions on food safety? He apparently had no comment on that point.
In the event that the clear increase of foodborne outbreaks and food import failures anticipated by Commissioner Hamburg becomes reality, can we expect representatives Ryan, Lucas, Latham and others of their ilk to own up to their mistake and take their share of the accountability for the debacle? There is no imagine to think so. Rather, the most likely response would be for them blame Fda for falling down on the job and then use such a purported "failure" to cluck about how the government can't be trusted to do anything and then to reaffirm their confidence in the same "market" that caused the problem.
What is the consumer supposed to do in the face of such an clear dysfunction in their government? To date, the consumer has been notably absent from the food protection debate. In the face of partisan intransigence and the result government dysfunction, it is time for the consumer to be heard because it is the consumer who has the power of the purse. To practice that power, the consumer must be informed by unbiased analytics of their own choosing. If such analytics cannot be provided by fiscally hamstrung government regulators and cannot be trusted by self-serving firm reports, then such analytics must arise anew.
Scientific pathology is expensive. Meaningful measurements often involve the use of instruments costing tens of thousands of dollars and operated by highly skilled technicians who, quite rightly, feel they deserve to be compensated for the skill set that has often taken them many years to acquire. Cheap and unreliable data are of use to no one. However, despite the huge variety of food products for sale in the U.S., there are still very many more habitancy interested in the results than there are products to be tested.
The collective has long enjoyed the right to share in the possession of secret clubs by purchasing one or more small shares of that firm in an change dedicated to the purpose. There is no imagine why the collective could not buy shares of an pathology of a given food product. Such a share may be quite affordably priced, say .00. Once consumers have purchased a enough number of shares to pay for the analysis, buy the stock and pay for the overhead such consolidation entails, the stock may be purchased and the pathology carried out. Copies of the results would then be sent back to each man who purchased a share. No governmental dysfunction involved.
Once a large number of analyses on the same stock were completed, the share-processing firm would compile all such date and release a compilation of results available to the collective (and at a reduced rate for any shareholder who had participated in the acquisition of such data). Meanwhile, analytic shareholders could, if they wished, express whether their congratulations or any concerns they might have to whether the firm or the regulatory group involved, or both. They would unmistakably have the right to share such information with other interested consumers of their choosing.
If repeated analyses of this kind showed no or only negligible amounts of the contaminant being analyzed then this principles would have identified a food that is "safe," at least insofar as the analyte being tested for. On the other hand, if a large number of samples showed principal elevations from what may be considered a "safe" level, then the constructor of such a food stock may well want to illustrate (or contradict) such findings to consumers or to any regulatory bodies consumers have chosen to share their results with.
Thus far, there is only one firm that offers analytic shares to the public. See the links below for details. At the moment, consumer-oriented testing of food products is only available for arsenic, lead and mercury. These three poisonous substances were chosen because they were felt to have the broadest applicability. Some background on each of these three might be useful.
The following conference makes full, use of the terms parts per million (ppm) and parts per billion (ppb). To result this discussion, you need to know what they mean. The easiest thing to do is to start from the definitions. A gram is the basic unit of weight in the metric system. A milligram is one thousandth of a gram. A microgram is one millionth of a gram (or one thousandth of a milligram). If a gram of material is analyzed for some analyte and in that one gram sample, a milligram of that analyte is found then one may say that the analyte is gift in the sample in the ratio of one part per thousand. Why, because the gram of sample contained, by definition, one thousand milligrams. If one of those was the analyte then the remaining 999 milligrams must have been something else. So, a ratio of one part per thousand must be the equivalent of one milligram per gram (mg/g). This may also be expressed as a division (1/1000 x 100 = 0.1%).
If one microgram of analyte is found in a one gram sample then one may say that the ratio of analyte weight to sample weight is one part per million (ppm) or the equivalent of one microgram per gram (µg/g). This makes sense because a gram must, by definition, consist of a million micrograms and in this example, the ratio of analyte to total sample weight is one in a million. However, this numerology needs to be intuitively understood by folks who don't work in laboratories all day. To make that happen, you need to understand just how big (or rather how small) a microgram is. This is tough because although you might be able to see a milligram as a kind of tiny dust-bunny, you are not likely to ever unmistakably see a microgram. Having an intuitive sense of something your eyes can't see is difficult.
So, sit down at a clean, flat table. Get your thumb out and use it to "stamp" the table as if you were using a rubber stamp. You have just added the weight of your fingerprint (approximately one microgram) to the weight of your table. Chances are that, contemplate the table as intimately as you care to and you wouldn't be able to see a thing. Now you know that a microgram is not a lot of stuff.
So, what about parts per billion? Same as before. A gram contains, by definition, one billion nanograms. So, if one gram of sample is found to consist of one nanogram of analyte, then we can say that the ratio of analyte to sample is one part per billion or one ppb or one nanogram per gram, (ng/g). To visualize a nanogram, divide your fingerprint into a thousand pieces. You will need to know one last thing. Sometimes concentrations of toxic substances are expressed in terms of micrograms per liter (µg/L) or micrograms per kilogram (µg/Kg or µg Kg-1). To make sense of this, remember that a liter is defined as one thousand milliliters and that a milliliter is defined as a volume being exactly one centimeter cubed (cm3). It just so happens that a cube of water one centimeter on each of its three sides, by definition, has a weight of one gram. So, µg/L = µg/1000 milliliters = µg/L = µg/1000 grams = µg/Kg = ng/g = ppb. At this point you may want to beat any scientist who expresses toxicant levels in terms of µg/L with a large stick for cleverly hiding a straightforward and understandable fact out there in plain sight. Before you do so, remember that scientists are habitancy too. If you don't love them, they will get weird on you (and may obfuscate).
Ok, now you are ready to look at and make up your own mind about definite heavy metal toxicants in food:
Arsenic (As)
Currently, the U.S. Has no limit on the number of arsenic that may be gift in food. The Environmental protection group (Epa) has considered that drinking water can consist of no more than 10 ppb of arsenic.
Not long ago, the Dr. Oz television show put together a program wherein they reported on a study they had sponsored. They measured total arsenic levels on a variety of fruit juices and found that a principal fraction of the samples tested showed arsenic levels higher than what Epa had established as the limit for drinking water. The airing of this program was initially castigated by Fda representatives, apparently on two grounds. The first was that habitancy drink a considerably greater weight of water per day than the daily weight of food ingested and so, they argued, it is Ok for food to have higher arsenic levels than water. The other was that the Dr Oz show measured only total arsenic. Since inorganic arsenic was more toxic than organoarsenical compounds, the Fda claimed that Dr. Oz was misleading the public. However, while it is true that organically bound arsenic is less toxic than inorganic arsenic, that doesn't mean organoarsenical compounds may all be dismissed as "safe." The Consumer's Union finally put this demand to rest by repeating the kind of contemplate first done by the Dr. Oz show but with a more sophisticated pathology which "speciated" organic arsenicals into their exact chemical form. This study showed that a large majority of the arsenic gift in fruit juice was unmistakably there as the most toxic, inorganic form, which made Fda arguments meaningless.
Fda officials and clear of their media supporters had no selection but to apologize to the Dr. Oz show. The consumer would like to think that the Fda is a variety of diligent experts working tirelessly to protect the consumer. The most revealing aspect of this whole incident was watching the Fda fly to the defense of the manufacturers complicated only to have their defensive activity crumble in the face of facts generated by a secret consumer group. consumer surrogates had to regulate the regulators.
Writing in the New York Times ( http://www.nytimes.com/2012/04/05/opinion/kristof-arsenic-in-our-chicken.html ) Nicholas Kristof reported that the great majority of broiler chickens available for sale in the U.S. consist of arsenic in their feathers, an indication of exposure to arsenic of the bird who grew the feathers. Mr. Kristof cited a work by K. E. Nachman et al. (Sci Total Environ. 2012 Feb 15;417-418:183-8. Epub 2012 Jan 11.), which stated that organoarsenical drugs (especially Roxarsone) are widely used in the yield of broiler chickens. An exam of the feathers of birds from a variety of sources showed that the arsenic attention in feather meal made from these birds ranged widely, from 44 - 4100 µg kg(-1). Of course, you are now savvy enough to know that this range plainly translates into 44 ppb - 4.1 ppm or, if you prefer, 4.4 - 410 times the arsenic limit for drinking water. Now, this study measured arsenic in feathers and not arsenic in the muscle meat, which is what habitancy unmistakably eat. The exact connection between arsenic levels in meat and arsenic levels in the feather meal is not known for chickens. Still, which bird would you prefer to see in your chicken sandwich?
And what happens to the feather meal? It is considered an organic fertilizer. It is located on the soil, where its arsenic article leaches into the soil to be picked up by anything (organic) crops are planted to be fertilized by the feather meal.
Right now is an especially seminal time for consumers to band together and procure hard data. Representatives Frank Pallone (D-Nj) and Rosa DeLauro (D-Ct) have proposed the "Arsenic arresting and protection from Lead Exposure in Juice Act of 2012," otherwise known as the "Apple Juice Act of 2012." This bill would want Fda to institute lead and arsenic standards for fruit juices within two years.
Lead (Pb)
The maximum number of lead Osha allows in the blood of a worker is approximately 400 ppb. In children, blood levels of lead of between 50 - 200 ppb have shown a correlation between Pb blood levels and execution on cognitive tests. Adult blood levels of 300 ppb have been related with peripheral nerve dysfunction and elevated blood pressure levels. The Environmental protection group (Epa) has set a limit for Pb in drinking water of 15 ppb, on the assumption that a man would drink two liters of water a day. This meant that the lead dose ingested from drinking water was minute to no more than 30 µg/day (i.e., 15 x 2000/1000 = 30).
It may be of interest for consumers to have a look at the Ora Laboratory hand-operated put out by the Fda Office of Regulatory Affairs, group of Field Science. This document contains a list of elements that may have toxicity for humans: Pb, Cd, Hg, As, Al, Ba, Li, Pt, Te, Ti, Sb, Be, Ga, In, V, Ni, Sr, Sn, Ge, Ag, Au, Bi, Tl, and U.
Section 6.1.2.1 of this same document contains the following quote: "There are no regulatory limits, i.e. Tolerances, for toxic elements in foods; sample results that exceed normal concentrations are brought to the attention of Cfsan, who will conduct an appraisal of possible health hazards from the quantity of the toxic element found based upon food consumption of the product."
Instead of regulatory limits, Fda uses an apparently much looser definition, that of "Provisional Daily Tolerable Total Intake" or (Pdtti). These have been adjusted downward over the years. The newest version claims that an intake is "safe" if it does not induce more than a rise of 10 ppb in Pb blood levels in children and cannot induce more than a 30 ppb rise in blood Pb level in adults. This has been translated into Pdtti's for some risk groups: children under seven years of age - 6 µg/day; children over seven years of age - 15 µg/day; women of childbearing age - 25 µg/day; all other adults - 75 µg/day.
It should be clear from this that Pdtti's for children of any age and women of childbearing age may be exceeded merely by drinking two liters of water a day. Equally clear is why consumers may want to decree the numbers that tell the lead article for the water they unmistakably drink and the food they unmistakably eat.
Mercury
There does exist a regulatory guideline for mercury in seafood (Cpg Section 540.600), if not for other foods. Fda's "action level" of 1 ppm for methylmercury expressed as mercury in fish was said to be have been established to "... Limit the consumer's methylmercury exposure to levels ten times lower than the lowest levels related with adverse effects." However, the World health society (Who) does not think that food containing more than 0.5 ppm methylmercury should be sold for human consumption. When exposed to a mercury attention of 0.2 ppm for only 30 minutes, greater than 95% of human spermatozoa had lost their potential to swim (Ernst, E. And J. G. Lauritsen (1991) result of organic and inorganic mercury on human sperm motility. Pharmacol. Toxicol. 68(6):440-444). It would appear, at the very least, that the lowest level of mercury related with "adverse effects" is open to debate.
Mercury is a vaporing metal. The natural degassing of the earth's crust is said to deliver some 10,000 tons/year of mercury to the air. Not to be outdone, man (mostly straight through his power generation efforts) delivers other 20,000 tons/year of mercury to the air. As a consequence, the mercury article of rainwater has been measured at 24.8 parts per trillion (ppt).
Fda has studied the mercury levels in a variety of seafoods and reported that canned albacore tuna fish had an mean mercury article of 0.83 ppm, very close to the "action level." One wonders if that explains why the quantum sizes listed on the label are often so unrealistically small (i.e., 2 oz.). Also, it is hard to understand why Fda recommends that seafood such as canned albacore tuna only be eaten intermittently. If the 1 ppm activity level already has a tenfold protection factor built into it, why can't a consumer enjoy a tuna fish sandwich twice in the same week?
The possibility of arsenic in chicken has been mentioned earlier. Lately, however, the manufactures has learned that ground up fish heads make good chicken feed. Depending upon the species of fish used, we may begin to see mercury in our chicken as well.
My oldest child is now pushing 40. When he was pushing 6, a friend gave him a T-shirt whose message read plainly "Question Authority." That was good advice, although it is not a license to indulge in apocalyptic imaginings. Still, when the duly-appointed or, for that matter, self-appointed "experts" tell the consumer stuff that doesn't make sense, that consumer must seek out the best sense he/she can manage. To that end, there is nothing quite like first-hand hard data. reconsider that no one disputes that arsenic and lead are carcinogens. The carcinogenicity of mercury in humans is in doubt because of flawed studies although long-term feeding experiments (in rats) have shown an increase in cancerous lesions in males but not females (Mercury Study Vol. V record to Congress; Epa-452/R-97-007; December 1997). Fda states, simply, that no carcinogen can be anticipated to have a "threshold" level, meaning some dose below which said carcinogen may be safely encountered. To my best knowledge, it has never been possible for consumers to affordably test foods they buy. Three such tests are now available. I hope consumers put this testing occasion to good use.
this guy Heavy Metal Testing for Arsenic, Lead and Mercury in Food Now available to Consumers this guy
No comments:
Post a Comment