Heavy Metal Testing for Arsenic, Lead and Mercury in Food Now Available to Consumers
The term "heavy metal" is a somewhat arbitrary and amorPh Meter 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 simple and understandable fact out there in plain sight. Before you do so, remember that scientists are people too. If you don't love them, they will get weird on you (and may obfuscate).
Heavy Metal Testing for Arsenic, Lead and Mercury in Food Now Available to Consumers
Heavy Metal Testing for Arsenic, Lead and Mercury in Food Now Available to Consumers
Heavy Metal Testing for Arsenic, Lead and Mercury in Food Now Available to Consumers
Heavy Metal Testing for Arsenic, Lead and Mercury in Food Now Available to Consumers
OK, now you are ready to look at and make up your own mind about specific heavy metal toxicants in Food:
ARSENIC (As)
Currently, the U.S. has no limit on the amount of arsenic that may be present in Food. The EnvironMental Protection Agency (EPA) has determined that drinking water can contain 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 significant 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 people 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 question to rest by repeating the kind of survey first done by the Dr. Oz show but with a more sophisticated analysis which "speciated" organic arsenicals into their exact chemical form. This study showed that a large majority of the arsenic present in fruit juice was actually there as the most toxic, inorganic form, which made FDA arguMents meaningless.
FDA officials and certain of their media supporters had no choice but to apologize to the Dr. Oz show. The consumer would like to think that the FDA is a collection 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 involved only to have their defensive action crumble in the face of facts generated by a private 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. contain 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 production of broiler chickens. An examination of the feathers of birds from a variety of sources showed that the arsenic concentration 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 simply 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 people actually eat. The exact relationship 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 placed on the soil, where its arsenic content leaches into the soil to be picked up by whatever (organic) crops are planted to be fertilized by the feather meal.
Right now is an especially seminal time for consumers to band together and gather hard data. Representatives Frank Pallone (D-NJ) and Rosa DeLauro (D-CT) have proposed the "Arsenic Prevention and Protection from Lead Exposure in Juice Act of 2012," otherwise known as the "APPLE Juice Act of 2012." This bill would require FDA to establish lead and arsenic standards for fruit juices within two years.
LEAD (Pb)
The maximum amount 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 performance on cognitive tests. Adult blood levels of 300 ppb have been associated with peripheral nerve dysfunction and elevated blood pressure levels. The Environmental Protection Agency (EPA) has set a limit for Pb in drinking water of 15 ppb, on the assumption that a person would drink two liters of water a day. This meant that the lead dose ingested from drinking water was limited 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 Manual put out by the FDA Office of Regulatory AffAirs, Division 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 assessment of potential 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 latest 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 several 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 determine the numbers that describe the lead content for the water they actually drink and the food they actually 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 associated with adverse effects." However, the World Health Organization (WHO) does not think that food containing more than 0.5 ppm methylmercury should be sold for human consumption. When exposed to a mercury concentration of 0.2 ppm for only 30 minutes, greater than 95% of human spermatozoa had lost their ability to swim (Ernst, E. and J. G. Lauritsen (1991) Effect 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 associated with "adverse effects" is open to debate.
Mercury is a volatile 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 through his power generation efforts) delivers another 20,000 tons/year of mercury to the Air. As a consequence, the mercury content 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 average mercury content of 0.83 ppm, very close to the "action level." One wonders if that explains why the portion 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 action level already has a tenfold safety 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 industry 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 simply "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. Consider 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 Report to Congress; EPA-452/R-97-007; December 1997). FDA states, simply, that no carcinogen can be expected 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 opportunity to good use.
Heavy Metal Testing for Arsenic, Lead and Mercury in Food Now Available to Consumers