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Tag: atrazine

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A recent report found that when a person is exposed to a little bit (or low doses) of a lot of different commonly encountered chemicals, than the combinations over time may cause changes that increase the risk of cancer (they may initiate cancer). Think about it - we are not exposed to just one chemical at a time (which is how chemicals are tested), but to mixtures or a "chemical soup". It is almost impossible to avoid them. As one of the researchers said: "We urgently need to focus more resources to research the effect of low dose exposure to mixtures of chemicals in the food we eat, air we breathe and water we drink." Testing mixtures of chemicals is currently not required by law.

The effects may be synergistic  - an enhanced effect that is more than the sum of the individual chemicals. And some chemicals may have bigger effects at smaller doses (typical of endocrine or hormone disruptors), than at larger doses - which is not how chemicals are typically viewed (typical view: the more you are exposed to a chemical, the greater the effect). A global task force of 174 scientists looked at 85 common everyday chemicals (at everyday low doses), and 50 were found to support cancer-related mechanisms (processes essential to cancer development). Examples of problematic chemicals that are common in everyday life: triclosan (in many soaps and personal care products), bisphenol A (in many plastics, including can linings), and atrazine (common herbicide or weedkiller). From the LA Times:

Combinations of 'safe' chemicals may increase cancer risk, study suggests

Lots of chemicals are considered safe in low doses. But what happens when you ingest a little bit of a lot of different chemicals over time? In some cases, these combinations may conspire to increase your risk of cancer, according to a new report. “Many [chemicals] have the possibility, when they are combined, to cause the initiation of cancer,” said Hemad Yasaei, a cancer biologist at Brunel University in England, one of the authors of the report. “They could have a synergistic or enhanced effect.”

This is not the way regulators typically think about cancer risk when they evaluate a compound’s safety.Normally, they test an individual chemical on laboratory animals, exposing them to progressively smaller amounts until it no longer causes malignant tumors to grow. Then they take that dose, determine the equivalent for humans, and apply what is called a “margin of safety” by declaring that some small fraction of that low dose is safe for people.

The big assumption driving the margin of safety is that a smaller amount of a chemical is less dangerous than a larger amount. (Think of the familiar axiom, “The dose makes the poison.”) But that’s not true for all chemicals, experts say. Some chemicals, such as those that mimic hormones, may actually be more dangerous at lower doses because the human body is exquisitely attuned to respond to minute amounts of natural hormones such as estrogen and testosterone.

And regulators haven’t required testing of mixtures of chemicals at all...Leroy Lowe, president of Canadian nonprofit Getting to Know Cancer and leader of the report published this week by the journal Carcinogenesis. The new report raises questions about whether this approach is adequate...Humans are exposed to about 80,000 man-made chemicals over their lifetimes, experts say. These chemicals are in the foods we eat, the water we drink and the air we breathe. "We live in a chemical soup,” said toxicologist Linda Birnbaum, director of the National Institute of Environmental Health Sciences, who was not involved in the new study.

The research team — a coalition of 174 researchers from 28 countries — set out to determine whether mixtures of these chemicals, at the very tiny concentrations found in the environment, could plausibly trigger the formation of cancerous tumors. They focused on 85 particular chemicals that were impossible to avoid in modern life, that were likely to disturb biological function and were not thought to pose cancer risks at the very low doses that people tend to ingest them.

The researchers scoured the scientific literature to understand how each of these chemicals could affect 10 important processes that are essential to cancer development. Among them: tumor-promoting inflammation, resistance to cell death and the formation of new blood vessels to feed malignant cells. In addition, they categorized whether each of the chemicals exerted biological effects at very low doses to which humans are ubiquitously exposed. (These doses are so small that they tend to be measured in parts per million or parts per billion.)
Of the 85 chemicals researchers examined, 50 were found to affect cancer-causing processes in the body, even at very low doses.

These 50 everyday chemicals included bisphenol A (used in manufacturing plastics), triclosan (often found in hand sanitizer and anti-bacterial soap) and atrazine (a commonly used herbicide). Since each of these chemicals affects different processes that could lead to cancer — bisphenol A makes cells less sensitive to signals to stop reproducing, for example, while atrazine encourages inflammation — it’s plausible that consuming mixtures of these chemicals is riskier than consuming any one individually.

More details about this report. From Science Daily: Cocktail of common chemicals may trigger cancer

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An article comparing the U.S. versus the European Union's approach to chemicals in products (including in cosmetics, personal care products, and foods), which explains why a number of chemicals are banned in Europe, but allowed in the U.S. From Ensia:

BANNED IN EUROPE, SAFE IN THE U.S.

Atrazine, which the U.S. Environmental Protection Agency says is estimated to be the most heavily used herbicide in the U.S., was banned in Europe in 2003 due to concerns about its ubiquity as a water pollutant. 

The U.S. Food and Drug Administration places no restrictions on the use of formaldehyde or formaldehyde-releasing ingredients in cosmetics or personal care products. Yet formaldehyde-releasing agents are banned from these products in Japan and Sweden while their levels — and that of formaldehyde — are limited elsewhere in Europe. In the U.S., Minnesota has banned in-state sales of children’s personal care products that contain the chemical.

Use of lead-based interior paints was banned in France, Belgium and Austria in 1909. Much of Europe followed suit before 1940. It took the U.S. until 1978 to make this move, even though health experts had, for decades, recognized the potentially acute — even deadly — and irreversible hazards of lead exposure.

These are but a few examples of chemical products allowed to be used in the U.S. in ways other countries have decided present unacceptable risks of harm to the environment or human health. How did this happen? Are American products less safe than others? Are Americans more at risk of exposure to hazardous chemicals than, say, Europeans?

Not surprisingly, the answers are complex and the bottom line, far from clear-cut. One thing that is evident, however, is that “the policy approach in the U.S. and Europe is dramatically different."

A key element of the European Union’s chemicals management and environmental protection policies — and one that clearly distinguishes the EU’s approach from that of the U.S. federal government — is what’s called the precautionary principle. This principle, in the words of the European Commission, “aims at ensuring a higher level of environmental protection through preventative” decision-making. In other words, it says that when there is substantial, credible evidence of danger to human or environmental health, protective action should be taken despite continuing scientific uncertainty.

In contrast, the U.S. federal government’s approach to chemicals management sets a very high bar for the proof of harm that must be demonstrated before regulatory action is taken.

This is true of the U.S. Toxic Substances Control Act, the federal law that regulates chemicals used commercially in the U.S. The European law regulating chemicals in commerce, known as REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals), requires manufacturers to submit a full set of toxicity data to the European Chemical Agency before a chemical can be approved for use. U.S. federal law requires such information to be submitted for new chemicals, but leaves a huge gap in terms of what’s known about the environmental and health effects for chemicals already in use. Chemicals used in cosmetics or as food additives or pesticides are covered by other U.S. laws — but these laws, too, have high burdens for proof of harm and, like TSCA, do not incorporate a precautionary approach.

While FDA approval is required for food additives, the agency relies on studies performed by the companies seeking approval of chemicals they manufacture or want to use in making determinations about food additive safety. Natural Resources Defense Council senior scientist Maricel Maffini and NRDC senior attorney Tom Neltner “No other developed country that we know of has a similar system in which companies can decide the safety of chemicals put directly into food,” says Maffini.  The two point to a number of food additives allowed in the U.S. that other countries have deemed unsafe. 

Reliance on voluntary measures is a hallmark of the U.S. approach to chemical regulation. In many cases, when it comes to eliminating toxic chemicals from U.S. consumer products, manufacturers’ and retailers’ own policies — often driven by consumer demand or by regulations outside the U.S. or at the state and local level — are moving faster than U.S. federal policy. 

Cosmetics regulations are more robust in the EU than here,” says Environmental Defense Fund health program director Sarah Vogel. U.S. regulators largely rely on industry information, she says. Industry performs copious testing, but current law does not require that cosmetic ingredients be free of certain adverse health effects before they go on the market. (FDA regulations, for example, do not specifically prohibit the use of carcinogens, mutagens or endocrine-disrupting chemicals.) 

For the FDA to restrict a product or chemical ingredient from cosmetics or personal care products involves a typically long and drawn-out process. What it does more often is to issue advisories.

At the same time, built into the U.S. chemical regulatory system is a large deference to industry. Central to current U.S. policy are cost-benefit analyses with very high bars for proof of harm rather than a proof of safety for entry onto the market. Voluntary measures have moved many unsafe chemical products off store shelves and out of use, but our requirements for proof of harm and the American historical political aversion to precaution mean we often wait far longer than other countries to act.