What is Arsenic? Why do I care? By the way, why is it in my food?
Arsenic (As), is a chemical element which has similar chemical properties with phosphorus (P). However, unlike phosphorus which is an essential element for life, arsenic does not play any constructive role. Itself and many of its compounds are potent poisons and known carcinogens. Partially due to its similarity with phosphorus, it can replace the latter within organism and thus disrupts some of essential roles phosphorus plays, such as energy transfer and utilization at cellular level. World Health Organization states “There is overwhelming evidence from epidemiological studies that consumption of elevated levels of arsenic through drinking-water and other sources is causally related to the development of cancer at several sites, particularly skin, bladder and lung.” It is ubiquitous in nature and appears in many drinking water sources. More significantly, it is intentionally deployed around us to kill the organisms we do not want. A lot of times, those arsenics ended up in our plate and beverages.
Really? How bad it is?
First, let’s have a sense of how much is too much. WHO establishes the recommended provisional tolerable daily intake level for arsenic to be 2.1 ug per kg of body weight[WHO2]. If one person is 70kg, then, daily intake level would be 147 µg per day. That is probably a good number to start.
Some of the most highly arsenic contaminated food in US are conventional chicken and long grain rice from Texas and Arkansas.
Arsenic in chicken meat comes from the arsenic intentionally added to chicken feed, in the form of Roxarsone. This practice started in 1950s. A little bit background about why this thing is needed in the first place. Genetically selected for fast growth, most of mass produced meat chicken (broiler) raised today have a life span of 6 to 7 weeks. They spent the their whole life in confined animal feeding operation or so called factory farming [FF], with no window and no exposure to natural sunlight. The unit they live in are extremely crowded. Needless to say, this kind of living environment is very conducive to diseases among those weak but fat chicken which are on steroids. Roxarsone helps control a parasitic ailment common to chickens called coccidiosis . In addition, it also growth enhancer and contributes to rosy-pink hue consumers have come to associate with fresh chicken meat. A detailed read about Roxarsone can be found here[Roxarsone].
The amount of arsenic in chicken has been found to be 0.4ppm (parts per million, or microgram per kg) according a research published in 2004[Tamar Lasky, Wenyu Sun, Abdel Kadry, and Michael K. Hoffman: Mean Total Arsenic Concentrations in Chicken 1989–2000 and Estimated Exposures for Consumers of Chicken, Environmental Health Perspectives, January 2004, VOLUME 112, NUMBER 1]. That means on a day of average luck, if you eat 8 oz of chicken, you take about 91 µg of total arsenic through chicken alone.
Then, there is rice. Thanks for long term cotton farming and its associated arsenic pesticide use, most of the US rice field in the south has high arsenic residual levels in soil and water. That means rice over there has pretty good level of arsenic in them as well. Rice grown in Texas and Arkansas tops the list with mean arsenic concentrations 0.258 and 0.190 ppm respectively[Yamilyj Zavala and John M Duxbury: Arsenic in Rice: I. Estimating Normal Levels of Total Arsenic in Rice Grain, ENVIRONMENTAL SCIENCE & TECHNOLOGY, 2008]. Rice from California has about half of that concentration(0.13 ppm). If you eat 200 grams of rice, something common in an Asian or Mexican diet, your total intake of arsenic from rice alone would be 52 µg if the rice is from Texas. And if you combine that much Texas rice with 8 oz grilled chicken, your arsenic consumption is already 143 µg. Already your daily limit.
What is the additional risk of over daily limit?
If your intake exceeds your daily limit most of the days, you may have additional risk from arsenic alone. National Resource Defense Council made a table based on National Academy of Science 1999 risk estimate[ArsenicRisk].
Arsenic Level in Tap Water
(µg, assuming 2 liters consumed/day)
Approximate Total Cancer Risk
|0.5 ppb||1||1 in 10,000|
|1 ppb||2||1 in 5,000|
|5 ppb||10||1 in 1,000|
|10 ppb||20||1 in 500|
|20 ppb||40||1 in 250|
|25 ppb||50||1 in 200|
|50 ppb||100||1 in 100|
Assuming your body weight is about 70kg, if you take total WHO daily limit of arsenic every day, you have greater than 1% additional life time cancer risk from arsenic alone than you daily take arsenic is limited to only 50 µg or one third of that.
Arsenic in drinking water
Current federal regulation requires arsenic level to be below 10 ppb, i.e. less than 20 µg if you drink 2 litres of water every day[CR]. That limit went into effective in 2006. Before that, the old one was 50 ppb. Most drinking water in US have met this regulation. The main problems comes from well water. 38% of well water supply in California did not comply with this new limit.
Sounds bad. Anything being done here?
After remaining silent on this issue for a few decades amid growing public concern of intentionally added arsenic in chicken, in June 2011, FDA finally acknowledged that chicken may contain arsenic which is “raising concerns of a very low but completely avoidable exposure to a carcinogen”[FDAArsenic]. At the same time, the manufacturer of Roxarsone, Pfizer, is suspending the sale of the additive. That is 12 years after European Union banned Roxarsone’s use. Finally an intentional source of Arsenic is gradually pulled out of chicken.
Going forward, it remains to be seen if the arsenic level in chicken drop substantially after this announcement. The role Roxarsone played in poultry industry was substantial and something else has to fill this void. What that new additive will bring to us. We have to wait and see.
What you can do to limit your arsenic intake.
- Eat organic chicken or eat less conventional chicken.
- Avoid long grain rice from Texas and Arkansas. Eat California rice.
- Filter your water using Multi Pure water filter or reverse osmosis, especially your water supply is well. The first water filter which gained NSF international certificate on arsenic reduction is MultiPure MP880 series. You can find it at www.bestfilters.com or [here]. The price is about 500 USD with replacement cartridge around 125 USD. The capacity of this water filter system is 600 gallons, that means about 20 cents per gallon. I have one of the similar models and have been very pleased with the water flow and water taste since I bought it a few years ago. It is most effective when your water comes from well which contains high level of arsenic. Since it is also a comprehensive water filtration system as well, the benefit does not come only from arsenic reduction.