Q & A: Lead in Aluminium Cookware
If you want to learn more, please visit our website Jinding.
Original question sent in by George Chapman, USA. Answers prepared by Swetha Lingala (The LEAD Group's Researcher) & Elizabeth O'Brien
George: "Is the lead (Pb) content of the common US aluminium alloy responsible for the perceived aluminium - Alzheimer's link? Apparently aluminium is readily filtered out of the body where as lead (Pb) is retained in the body.
Lead (Pb) adds some beneficial material property to the aluminium alloy. Could the small amount of consumed lead (Pb), leached out from the aluminium alloy commonly used to manufacture soda cans, cooking ware, etc.. , accumulate over decades in the body and cause appreciable health problems? If so why do we not hear more about this lead (Pb) problem?"
Swetha: "Hi George,
Thank you for your fascinating about Aluminium alloy containing lead(Pb). Even our lead expert, Elizabeth O'Brien was not aware of it.
I found the following confirmation that lead can be added to Aluminium Alloys:
''Lead (Pb) and Bismuth (Bi) &#; Lead and bismuth are added to aluminium to assist in chip formation and improve machinability. These free machining alloys are often not weldable because the lead and bismuth produce low melting constituents and can produce poor mechanical properties and/or high crack sensitivity on solidification."
[http://www.esabna.com/us/en/education/blog/how-and-why-alloying-elements-are-added-to-aluminum.cfm]
The following article implies that Aluminium Alloy contains lead:
"In , the development efforts at ALCOA's Massena Operations began with the objective to create a free machining alloy that would be comparable to a lead bearing alloy, , in strength, machinability, corrosion resistance, anodizing, brazing, and welding responses while eliminating the health and environmental concerns associated with lead. "
".....Proclaimed as the fastest growing new product in automotive and miscellaneous applications the full cold finished product line in T8, T9 and T651 tempers excel in markets where , , aluminium alloys and 12L14 steels are used today."
[http://papers.sae.org//]
The Following article doesn't indicate that Aluminium Alloy contains lead but shows the presence of lead and bismuth in some Aluminium Alloys:
"Lead. Normally present only as a trace element in commercial-purity aluminium, lead is added at about the 0.5% level with the same amount as bismuth in some alloys ( and ) to improve machinability."
[ http://www.keytometals.com/Article55.htm]
The following table shows that Lead (and any other element not specified separately) is limited in Aluminium Alloy to 0.05%, but unfortunately the table is not referenced:
Wrought aluminium alloy composition limits (% weight)
Alloy
Si
Fe
Cu
Mn
Mg
Cr
Zn
V
Ti
Bi
Ga
Pb
Zr
Limits&#;&#;
Al
Each
|Total
0.40-0.8
0.7
0.15-0.40
0.15
0.8-0.12
0.04-0.35
0.25
0.05
0.15
remainder
[ http://en.wikipedia.org/wiki/Aluminium_alloy]
The Following article shows that Aluminium Alloy does not contain lead (Pb):
In , Luxfer switched to a "" alloy, which does not contain lead.
[http://www.scubadiving.com/gear/accessories/consumers-guide-scuba-tanks]
Could you please provide references which state the actual level of lead found in Aluminium Alloy?
George: "Yes my mistake it's not . Here's the list of Aluminum alloys I found earlier on line (www.aluminum.org/sites/default/files/Teal_Sheets.pdf ).
In the past what alloy did they make cookware out of? You can see many alloys with Pb as a constituent.
I'm sure things have changed now, perhaps this generation of Alzheimer sufferers were exposed to decades of aluminium alloys containing lead.
Thanks for the response & articles,
George:
Elizabeth: "You raise some very important questions and sadly my volunteer researcher has been unable to come into work for several weeks due to lack of a baby sitter
And today when she (Swetha) did come in, she only had time to put together the following info, which doesn't go all the way to answering the question as to whether the aluminium/aluminium cookware we all used in decades gone by, and which is likely still being used widely in many countries, contains lead. There's possibly a different answer in every country. Well worth finding out though.
Cheers,
Elizabeth O'Brien"
Swetha:
http://is.gd/XYEcMd
"The conventional aluminium cookware is usually made from a single layer of aluminium alloy which may be anodized on the outside surface and given a non-stick surface on the inside, cooking surface. Oftentimes such cookware is made from Aluminium alloy or a like aluminium alloy which offers higher strength than purer aluminium such as aluminium."
http://www.azom.com/article.aspx?ArticleID=
"The Aluminium / Aluminium alloy is used in ductwork, chemical equipment, and general sheet metal work. It is also used in manufacturing the following items:
Cooking utensils
Builder's hardware
Pressure vessels
Ice cube trays"
George: "Hi Swetha,
Thank you so much for looking into this and providing interesting links. I'll have to look into the aluminium hydroxide formation and toxicity. It would be interesting to see if some of the detrimental effects blamed on aluminium can be linked to lead or other known toxic alloy additives. Perhaps we can find a healthy metal for cooking - so far it sounds like surgical stainless steel is the best.
Thanks again for following up on this.
George Chapman"
Swetha: "Hi George,
Regarding recommended cookware metals, in the book "Clean, Green and Lean: Get rid of the toxins that make you fat - Drop the weight in 30 days." Author Dr Walter Crinnion, ND, writes:
'Cookware. Get rid of chemical-spewing non-stick pans. Ceramic titanium and porcelain-enamelled cast iron are great alternatives.' (Page 141)
But because iron deficiency is associated with increased lead absorption from the gut, and because enamel glazes on cast iron eliminate the possibility of adding iron to the food during cooking, the following recommendation on the best cookware metal could actually be more lead-safe:
&#;Cast iron cookware. Cast iron is known for its durability and even heat distribution. Unglazed cast iron can transfer notable amounts of iron into food, but unlike the metals that come off other types of pots and pans, iron is considered a healthy food additive by the U.S. Food and Drug Administration.&#;
(http://www.mnn.com/food/healthy-eating/questions/whats-the-safest-cookware)
It is also apparent from the following that cast iron cookware (without any coating/glaze) is recommended whenever reducing lead exposure is the aim:
For vegetarians or vegans a good supplementation technique is through cooking acidic vegetables (such as tomatoes or cabbage) in non enamelled cast iron pots which has been consistently shown to significantly increase dietary iron (165,60,166,167); a technique that works equally well for non-vegetarians and which may be preferable to iron supplementation in pill form. For this purpose it should be noted that materials do not have to be naturally high in iron to improve iron status (168). Should there be difficulty in finding non-enamelled cast iron cookware Lodge Cast Iron Cookware of Tennessee provides a range that is widely distributed. Note that the iron in many vegetables is more bioavailable (capable of being absorbed) when cooked rather than raw (341).
Iron cooking vessels: The following items have their iron content more than doubled when cooked in iron container without a protective surface. Rear Row: red cabbage, tomato, rice, corn meal Front Row: tomatoes, capsicum (bell or banana peppers in USA), pureed vegetables, wild rice, apple sauce, scrambled egg, corn meal, Foreground: scrambled egg Not pictured: milk
(https://lead.org.au/lanv9n3/Iron_Nutrition_and_Lead_Toxicity_Short.pdf - page 6)
So, despite the comment made about the iron of cast iron cooking pots not being absorbed (in the article I previously sent you, at http://www.happycookingco.com/hidden-dangers.cfm ) I find the information above on our own website to be better-referenced.
Returning to my search for the answers to the questions your emails raise...
1. Which Aluminium Alloys were used in United States in the past to make cooking pots?
Below URL shows series and series Aluminium Alloys ARE used in making cookware:
http://www.meyer-mab.com/technical-information/
Specifically, the above URL states:
&#;3XXX Series - Due to its excellent formability, has a wide range of uses including cookware.The addition of Magnesium gives it [] strengths approaching along with great corrosion resistance and good formability. These properties make a good candidate for storage tanks, pressure vessels and cookware.&#;
&#;8XXX Series - This series comprises alloys that use less common elements, including Tin, Iron, Nickel and Lithium. The Lithium alloys are attractive for some aerospace applications due to their very light weight, high strength and increased ability to stretch without breaking. Other uses for 8XXX alloys include cookware, conductor material, and some high temperature applications.&#;
Next time I am in the office I&#;ll search for whether the above-mentioned , and series aluminium alloys contain any lead.
Skipping ahead to Q. 5 (Are there any lead containing Aluminium Alloys still used anywhere in the world to make cooking pots?), I have found the following three related articles about scrap metal being used to make aluminium pots in Cameroon, which release hundreds of times the Californian daily lead limit from consumer products, into the food. I am wondering what inspired your original question? Was it any of these articles (or another article about this Cameroon study):
http://www.voanews.com/content/africa-aluminum-cookware-15aug14/.html;
http://www.sciencedaily.com/releases//08/.htm;
http://www.sciencedirect.com/science/article/pii/S
[please find this last one attached as Weidenhame et al Lead exposure from
aluminium cookware in Cameroon FULL.pdf]
The company is the world’s best Aluminium Series supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.
I hope that aluminium alloys for cookware were never made so carelessly from lead-containing scrap metal in the developed world, as the above articles report is occurring now in Cameroon and probably the rest of Africa as well as in Bangladesh and Thailand and possibly the rest of Asia, but I&#;ll keep researching just in case... until next week....
Kind regards
Swetha Lingala (with help from Elizabeth O&#;Brien)"
Swetha: "Hi George,
2. Do those Aluminium Alloys (, , ) contain Lead?
As per my research the URL shown below shows these is no presence of Lead (Pb) in the above mentioned Aluminium Alloys.
http://www.suppliersonline.com/propertypages/.asp
http://www.suppliersonline.com/propertypages/.asp
Next time I am in the office I&#;ll search for whether the series aluminium alloys contain any lead.
Thanks
Swetha Lingala"
Swetha: "Hi George,
I am still searching the internet to answer the following Questions:
Which Aluminium Alloys were used in United States in past to make cooking parts?
Do those Aluminium Alloys contain Lead?
If so, how much lead?"
Swetha: "Hi George,
As there is no presence of Lead in US cookware made of Aluminium Alloys (, , series), it gives answers to the remaining 3rd and 4th Questions.
3) If so, how much lead?
4) Are there any lead containing Aluminium Alloys still used in US to make cooking pots?
Regarding Question 5:
5) Are there any lead containing Aluminium Alloys still used anywhere in the world to make cooking pots?
A) As per my research the African countries and probably other under-developed countries are still using and making aluminium cooking utensils using scrap metal and thus the cookware can contain Lead.
For your ref:
http://www.voanews.com/content/africa-aluminum-cookware-15aug14/.html
http://www.sciencedaily.com/releases//08/.htm"
I realise that the following quotes don't answer any of the above Questions, but I think you will find the information very interesting nevertheless.
Very soft metal. Extreme chemical reaction between food and pan. "All Vegetables cooked in Aluminium produce hydroxide poison which neutralizes digestive juices, producing stomach and gastrointestinal trouble, such as stomach ulcers and colitis." Dr. A. McGuigan's Report on Findings for the Federal Trade Comm. In Docet Case No. 540 Washington, D.C. Note: The sale of aluminium cookware is prohibited in Germany, France, Belgium, Gr. Britain, Switzerland, Hungary and Brazil.
Glass / Enamel Coated
Poor heat distribution. Foods stick and burn. Contains lead. Lead can cause reproductive harm and learning disabilities. [ http://www.happycookingco.com/hidden-dangers.cfm ]
Interestingly also, the following website lists stainless steel alloys, some of which contain lead:
http://www.yamco-yamashin.com/en/products/guide_stainless_steel.html
So that might be more research for another day, to work out if stainless steel cookware contains lead.
In trying to answer the above questions, today I located the following information:-
1. "The series is made up of alloys of aluminium and manganese. These alloys are not as strong as the series, but they also have good machinability. Alloys in this series are used for cooking utensils; storage tanks; aluminium furniture; highway signs and roofing." [http://www.chemistryexplained.com/elements/A-C/Aluminum.html ]
I will be back next week to research some more."
George: "Swetha,
Thank you so much for looking into this! I guess lead alloys are not intentionally used in aluminium cookware, nor is lead from cookware responsible for the Alzheimer/aluminium link.
I'll have to look into what it would take to remove lead from scrap metal so it doesn't end up in cookware in Cameroon. I would think something like spark gap spectrometry would be able to identify lead in an aluminium alloy. The real key would be to sort it out before it gets mixed in with aluminium.
I'll have to look into how cookware is made in Cameroon. Are there a few large metal smelting facilities, or do people make there own cookware? If there are only a few smelters the lead would probably be easier to sort out. If individuals are making their own cookware, one would have to go door to door offering to test & replace cookware.
Thanks again,
George Chapman"
Swetha: "George,
Your thoughts are so interesting, I am CC'ing this to our colleagues who were responsible for the Research and News articles about Leaded Aluminium pots in Cameroon.
Perhaps Jeffrey, Gilbert or Perry can send us the original copy of the below URL as we have only the abstract of it.
http://www.sciencedirect.com/science/article/pii/S
Hopefully all the ideas in the article and maybe George&#;s below can be incorporated into a Health programme for the affected people, with articles in the media and social networks.
Thank you,
Yours Sincerely
Swetha Lingala
Researcher"
Jeff Weidenhamer, Ph. D.: "Swetha,
Thanks for your . Our judgment is that the lead in these aluminium alloys (not large amounts -- maximum 637 ppm by X-ray fluorescence) is picked up from the scrap materials used to make them. Please let me know if there are any other questions.
The paper is available through the OK International website at this address:
http://www.okinternational.org/docs/Final%20pb%20pots%20STOTEN%.pdf
In case you missed it, along the right
side of the science direct posting is a short video presentation about the
research project:
http://www.sciencedirect.com/science/article/pii/S
Jeff Weidenhamer"
If you&#;re planning on using aluminium in a project, then it&#;s important to be aware of the different types available. There&#;s not just one single option. The popular metal is available in a variety of different aluminium grades, which are categorised into different series.
Sound confusing? Unless you&#;re an expert in metals, you probably need aluminium grades explained in simple terms. In this short guide, we&#;ll cover everything you need to know to make the right choice, from the different grade series to their applications.
Every aluminium grade is associated with a specific alloy.
There are eight aluminium grade series overall.
Alloys are formed by combining two or more types of metal. This optimises the metal&#;s features.
Aluminium grades are categorised using a series of numbers...
series alloys consist of at least 99% aluminium...
series alloys are combined with copper...
series alloys contain manganese...
series alloys are combined with silicone...
series alloys are predominantly combined with magnesium...
Containing both magnesium and silicone, series alloys are very strong and workable...
series alloys are predominantly combined with zinc...
series alloys contain a variety of other elements...
1
There are eight grade series of aluminium. Each grade is associated with a particular alloy. Alloys refer to metals which have been made by combining two or more types of metal...
Different grades are associated with different strengths and applications, so you&#;ll need to choose carefully.
2
Aluminium grades are categorised using a series of four numbers:
The first number denotes the primary alloying element, which is how alloys are split into series
The second number refers to specific modifications to one of the alloying elements
Digits 3 and 4 are random numbers associated with specific alloys
So, what are the eight series of aluminium grades you can choose from?
Whilst there&#;s no such thing as 100% pure aluminium, the series is as close as it gets. This grade features alloys that are made up of at least 99% aluminium content.
These alloys are highly workable, with a variety of options for working the aluminium, including everything from welding to hard forming. Other benefits include corrosion resistance and strong conductivity. The Metal Store stocks aluminium sheet metal in grade .
Thanks to its high electrical and thermal conductivity, these grades are frequently used for electrical and chemical applications.
This grade is combined with copper. Through specialist heat treatment, it&#;s possible to optimise the toughness of these alloys. They feature fantastic machinability and good strength. On the other hand, they suffer from poor corrosion resistance, so may require painting with a higher quality alloy in some circumstances.
series grade aluminium is frequently used for aerospace applications.
Alloys from this grade feature manganese and are great all-rounders that can be applied to a variety of uses. They feature good strength, temperature stability, and workability, and are also resistant to corrosion. This means that as well as everyday uses, they can also be used in extreme conditions.
series alloys are used in day-to-day applications, including kitchen utensils. They are also used in a variety of sheet-metal applications, and in heat exchanger components.
Combined with silicon, grade aluminium alloys have a lower melting point, making them a popular option for welding wire and brazing alloys. They also feature strong electrical and thermal conductivity, as well as resistance to corrosion.
Whilst silicon alone can&#;t be heat-treated, there are several alloys that are suitable for heat treatment.
These alloys are commonly used in the automotive industry.
This aluminium grade series is combined primarily with magnesium, but may also features other elements, including manganese. These alloys are strong, easy to weld and are very suitable for working and forming. We supply aluminium checker plate in grade , due to its high strength and corrosion resistance.
Thanks to its corrosion resistant properties, this grade is a popular option for use in marine environments, and for storage tanks. With this being said, some series alloys containing magnesium shouldn&#;t be exposed to very high temperatures due to the potential for corrosion cracking.
This series of alloys features both magnesium and silicon, which forms magnesium-silicide. Known for being very workable and heat treatable, series aluminium is strong and corrosion resistant. You&#;ll also find they&#;re good to form, weld and machine. The highest strength alloy in this series is , which we stock in several products, including aluminium angle, box section, flat bar and square bar.
Due to their broad strengths, these alloys are frequently used across a variety of industries, including construction, architecture and fabrication.
These alloys are predominantly combined with zinc, but may also contain magnesium, copper or chromium if you&#;re interested in heat-treating the metal. Incredibly strong, many of the alloys in this series match steel in their strength. They&#;re also tough and stress-resistant but can be at risk of corrosion.
Thanks to their exceptional strength, these alloys are commonly used in the aerospace industry and in the production of sports equipment.
series aluminium alloys are combined with many other elements, including nickel, lithium and iron. These alloys are not commonly used but are developed for specific applications in certain industries.
This niche series of alloys is most commonly used in very specific applications within the engineering or aerospace industries.
Trusted polished aluminium suppliers in the UK
Aluminium is a versatile metal with a variety of applications. Whether you&#;re looking for aluminium sheet or T section, you&#;ll find exactly what you need at The Metal Store.
If you&#;d like to know more about our aluminium supplies why not get in touch with our friendly team today? Call us on 875 479 or send a quick to [ protected].
For more information, please visit Coated Aluminum Coil.