Lead author and assistant research biologist Robert Miller and co-authors Arturo Keller and Hunter Lenihan - both Bren School professors and lead scientists at the UC Center for Environmental Implications of Nanotechnology (UC CEIN) - Bren Phd student Samuel Bennett, and Scott Pease, a former UCSB undergraduate and current graduate student in public health at the University of Washington, found that the nanoparticulate form of titanium dioxide (TiO2) exposed to ultraviolet radiation (UVR) can be toxic to marine organisms.

"Application of nanomaterials in consumer products and manufacturing is quickly increasing, but there is concern that these materials, including nanoparticles, may harm the environment," says Miller. "The oceans could be most at risk, since wastewater and factory discharges ultimately end up there."

Nano-titanium dioxide is highly reactive to sunlight and other forms of ultraviolet radiation (UVR,) the authors write, adding that TiO2's property of generating reactive oxygen species (ROS) when exposed to UVR makes it useful in antibacterial coatings and wastewater disinfection, and potentially valuable as an anti-cancer agent.

Until now, they say, no research has demonstrated that photoactivity causes environmental toxicity of TiO2 under natural levels of UVR.

"Previous experiments have suggested that TiO2 does not affect aquatic organisms, but these experiments used artificial lighting that generated much lower levels of UVR than sunlight," Miller explains. "In these new experiments, we used lights simulating natural sunlight."

But now, the authors say, "We show that relatively low levels of ultraviolet light, consistent with those found in nature, can induce toxicity of TiO2 nanoparticles to marine phytoplankton, the most important primary producers on Earth.

"With no exposure to UVR, the TiO2 had no effect on phytoplankton, but under low-intensity UVR, ROS in seawater increased with increasing concentrations of nano- TiO2."

The concern is that rising concentrations of nano- TiO2 "may lead to increased overall oxidative stress in seawater contaminated by TiO22, and cause decreased resiliency of marine ecosystems."

The authors suggest, therefore, that UVR exposure should be considered when conducting experiments to determine the ecotoxicity of nanomaterials having photoactive potential.

Children have the right to a safe and healthy environment. Since newborns and very small children spend most of their time indoors, this safe and healthy environment is also a synonym for indoor environment. Products surrounding the baby at this early stage of its development, and in particular their chemical content, and baby's exposure to it, determine to a large extent how healthy these surroundings are. Toys are developed and sold solely for the education and entertainment of children.

A toy is not a necessity for a child, no compromises on health and safety should therefore be made. After the US, Europe is the second biggest market for toys, a total market estimated to 62 billion Euros a year. As much as 60% of all toys on the market are newly developed each year, with more than 86% of toys being manufactured in China. Despite claims that toys sold in European stores are safe, a number of harmful substances like heavy metals, carcinogens or endocrine disrupters are still allowed. Whereas toxicologists agree that there is no safe limit for lead, the limit for lead is very high in the new Toys Safety Directive (TSD). In addition, the law is broken on numerous occasions. This is evident from the EU RAPEX alert system: 30% of the items to be removed from the market are toys, many of these for 'chemical reasons': even customs departments recognize that they hardly can control the quality of products entering the European market. Results of a sample toy test that WECF did recently, matching the results of a recent test by Stiftung Warentest in Germany show heavy metals in children's jewelry and wooden
pizza pieces, banned phthalates in children's painting aprons, formaldehyde in wooden toys. Time and time again, harmful substances are found in toys. Parents obviously cannot assume that children's toys are healthy and safe.

Download the paper

 

As people seek healthier dietary regimens they often turn to things labeled "organic." Lurking in the background, however, is an ingredient that may be a hidden source of arsenic-an element known to be both toxic and potentially carcinogenic.

Organic brown rice syrup has become a preferred alternative to using high fructose corn syrup as a sweetener in food. High fructose corn syrup has been criticized as a highly processed substance that is more harmful than sugar and is a substantial contributor to epidemic obesity. Unfortunately, organic brown rice syrup is not without its faults.

Dartmouth researchers and others have previously called attention to the potential for consuming harmful levels of arsenic via rice, and organic brown rice syrup may be the latest culprit on the scene.

With the introduction of organic brown rice syrup into food processing, even the savvy consumer may unknowingly be ingesting arsenic. Recognizing the danger, Brian Jackson and other Dartmouth researchers conducted a study to determine the concentrations of arsenic in commercial food products containing organic brown rice syrup including infant formula, cereal/energy bars, and high-energy foods used by endurance athletes.

The results were alarming. One of the infant formulas had a total arsenic concentration of six times the U.S. Environmental Protection Agency's (EPA) safe drinking water limit of 10 parts per billion (ppb) for total arsenic. Cereal bars and high-energy foods using organic brown rice syrup also had higher arsenic concentrations than those without the syrup.

Jackson,director of the Trace Element Analysis Core Facility at Dartmouth and a member of the college's National Institute of Environmental Health Sciences (NIEHS) -funded Superfund Research Program, is lead author on the study published February 16, 2012, in Environmental Health Perspectives. His collaborators include researchers in Dartmouth's EPA and NIEHS-funded Children's Environmental Health and Disease Prevention Center.

Jackson and his colleagues purchased commercial food products containing organic brown rice syrup and compared them with similar products that didn't contain the syrup. Seventeen infant formulas, 29 cereal bars, and 3 energy "shots" were all purchased from local stores in the Hanover, N.H., area.

Of the 17 infant milk formulas tested, only two had listed organic brown rice syrup as the primary ingredient. These two formulas, one dairy-based and one soy-based, were extremely high in arsenic, more than 20 times greater than the other formulas. The amount of inorganic arsenic, the most toxic form, averaged 8.6 ppb for the dairy based formula and 21.4 ppb for the soy formula.

This is of concern because these concentrations are comparable to, or greater than, the current U.S. drinking water limit of 10 ppb, and that limit does not account for the low body weight of infants and the corresponding increase in arsenic consumption per kilogram of body weight.

The Dartmouth researchers also tested 29 cereal bars and three types (flavors) of an energy product obtained from a supermarket. Twenty-two of the bars listed at least one of four rice products-organic brown rice syrup, rice flour, rice grain, and rice flakes-in the first five ingredients.  

The cereal bars ranged from 8 to 128 ppb in total arsenic; those that had no rice ingredients were lowest in arsenic and ranged from 8 to 27 ppb, while those that did contain a rice ingredient ranged from 23 to 128 ppb total arsenic.

With recent news coverage of the potential for rice to contain arsenic, educated consumers may be aware that cereal/energy bars containing rice ingredients could also contain arsenic.

The authors note that, "By contrast the energy shots are gel-like blocks and, like the infant formulas, it would not be immediately apparent to the consumer that these too are rice-based products." One of the three flavors of energy shots tested revealed about 84 ppb total arsenic (100 percent inorganic arsenic), while the other two showed 171 ppb total arsenic (53 percent inorganic arsenic).

Jackson and his colleagues conclude that in the face of the increasing prevalence of hidden arsenic in food, and the absence of U. S. regulations in this area, "there is an urgent need for regulatory limits on arsenic in food."