Household detergents, shampoos may form harmful substance in wastewater

Scientists are reporting evidence that certain ingredients in shampoo, detergents and other household cleaning agents may be a source of precursor materials for formation of a suspected cancer-causing contaminant in water supplies that receive water from sewage treatment plants. The study sheds new light on possible environmental sources of this poorly understood water contaminant, called NDMA, which is of ongoing concern to health officials. Their study is in ACS' Environmental Science & Technology, a semi-monthly journal.

William Mitch and colleagues note that scientists have known that NDMA and other nitrosamines can form in small amounts during the disinfection of wastewater and water with chloramine. Although nitrosamines are found in a wide variety of sources - including processed meats and tobacco smoke - scientists know little about their precursors in water. Past studies with cosmetics have found that substances called quaternary amines, which are also ingredients in household cleaning agents, may play a role in the formation of nitrosamines.

Their laboratory research showed that when mixed with chloramine, some household cleaning products - including shampoo, dishwashing detergent and laundry detergent - formed NDMA. The report notes that sewage treatment plants may remove some of quaternary amines that form NDMA. However, quaternary amines are used in such large quantities that some still may persist and have a potentially harmful effect in the effluents from sewage treatment plants.

Environmental Science & Technology: "Quaternary Amines As Nitrosamine Precursors: A Role for Consumer Products?" [Environ. Sci. Technol., 2010, 44 (4), pp 1224?1231; DOI: 10.1021/es902840h].

Better animal-free test for chemicals that can cause contact dermatitis

Scientists are reporting development of a fast, simple, inexpensive method for determining whether chemicals in consumer products and workplaces may cause skin allergies in people - a method that does not involve use of animals. Their study appears in ACS' Chemical Research in Toxicology, a monthly journal.

Itai Chipinda and his colleagues note the existence of public sentiment against the use of animals to determine whether ingredients in consumer soaps, shampoos and other consumer products, and workplace chemicals, may cause skin sensitization and contact dermatitis. Chemicals cause dermatitis by bonding to proteins in the skin, and then aggravating the immune system so that redness, irritation, itching, and other symptoms occur. Existing chemical tests use substances like glutathione that mimic skin proteins and bond to allergy-causing ingredients. None, however, are suitable for use in detecting the critical early stages of skin sensitization, the scientists say.

Instead of glutathione, Chipinda and his team developed a test with nitrobenzenethiol as the skin protein surrogate. When used on 20 different chemicals known to cause skin irritation, the test produced positive results. It produced negative results when used to test substances that usually do not produce skin sensitization. "This simple, rapid and inexpensive absorbance-based method has great potential for use as a preliminary screening tool for skin allergens," the report states.

Chemical Research in Toxicology: "Rapid and Simple Kinetics Screening Assay for Electrophilic Dermal Sensitizers Using Nitrobenzenethiol" [Chem. Res. Toxicol., 2010, 23 (5), pp 918?925; DOI: 10.1021/tx100003w].

Air traffic poised to become a major factor in global warming

The first new projections of future aircraft emissions in 10 years predicts that carbon dioxide and other gases from air traffic will become a significant source of global warming as they double or triple by 2050. The study is in ACS' Environmental Science & Technology, a semi-monthly journal.

Bethan Owen and colleagues note that aviation is not now one of the main drivers of global warming, with international aviation (source of 60 percent of carbon dioxide emissions from aircraft) not even included in the Kyoto Protocol. Global air traffic currently contributes to between 2 and 3 percent of carbon dioxide emissions - the main "greenhouse" gas linked to global warming.

The scientists' computer model forecast that emissions of carbon dioxide will likely double or triple within the next 50 years. By 2100, carbon dioxide emissions could increase by up to seven times the current levels, they say. "Even though there have been significant improvements in fuel efficiency through aircraft technology and operational management, this has been outweighed by the increase in air traffic," the study states.

Environmental Science & Technology: "Flying into the Future: Aviation Emissions Scenarios to 2050" [Environ. Sci. Technol., 2010, 44 (7), pp 2255?2260; DOI: 10.1021/es902530z].

Little-known mouth fluid may lead to test for gum disease

A little-known fluid produced in tiny amounts in the gums, those tough pink tissues that hold the teeth in place, has become a hot topic for scientists trying to develop an early, non-invasive test for gum disease, the No. 1 cause of tooth loss in adults. It's not saliva, a quart of which people produce each day, but gingival crevicular fluid (GCF), produced at the rate of millionths of a quart per tooth. The study, the most comprehensive analysis of GCF to date, appears in ACS' monthly Journal of Proteome Research.

Eric Reynolds and colleagues note that GCF accumulates at sites of inflammation in the crevice between teeth and gums. Since dental workers can easily collect the fluid from patients, GCF has become a prime candidate for a simple inexpensive test to distinguish mild gum disease from the serious form that leads to tooth loss. But researchers have little information about the chemical composition of GCF.

The scientists collected GCF samples from 12 patients with a history of gum disease. Using high-tech instruments, they identified 66 proteins, 43 of which they found in the fluid for the first time. The fluid contained proteins from several sources, including bacteria and the breakdown products of gum tissue and bone, they note. They also identified antibacterial substances involved in fighting infection. The findings advance efforts to develop an early test for gum disease, they suggest.

Journal of Proteome Research: "Mass Spectrometric Analyses of Peptides and Proteins in Human Gingival Crevicular Fluid" [J. Proteome Res., 2010, 9 (4), pp 1683?1693; DOI: 10.1021/pr900775s].

Proteins in unroasted coffee beans may become next-generation insecticides

Scientists in Brazil are reporting for the first time that coffee beans contain proteins that can kill insects and might be developed into new insecticides for protecting food crops against destructive pests. Their study, which suggests a new use for one of the most important tropical crops in the world, appears in ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Peas, beans and some other plant seeds contain proteins, called globulins, which ward off insects. Coffee beans contain large amounts of globulins, and Paulo Mazzafera and colleagues wondered whether those coffee proteins might also have an insecticidal effect. The high heat of roasting destroys globulins, so that they do not appear in brewed coffee.

Their tests against cowpea weevil larva, insects used as models for studying the insecticidal activity of proteins, showed that tiny amounts of the coffee proteins quickly killed up to half of the insects. In the future, scientists could insert genes for these insect-killing proteins into important food crops, such as grains, so that plants produce their own insecticides, the researchers suggest. The proteins appear harmless to people.

Journal of Agricultural and Food Chemistry: "Purification of Legumin-Like Proteins from Coffea arabica and Coffea racemosa Seeds and Their Insecticidal Properties toward Cowpea Weevil (Caliosobruchus maculates) (Coleoptera: Bruchidae)" [J. Agric. Food Chem., 2010, 58 (5), pp 3050?3055; DOI: 10.1021/jf9037216].

Nanotech breath sensor detects diabetes and potentially serious complication

Scientists are reporting development and successful testing of a sensor that can instantly tell whether someone has Type I diabetes. It could also be used by emergency room doctors to determine whether a patient has developed diabetic ketoacidosis, a potentially serious complication that happens when diabetics do not take enough insulin. Someday the technology may also be used by diabetics, in their own homes, to determine whether they need more insulin. A report on the sensor appears in ACS' Analytical Chemistry, a semi-monthly journal.

Professor Sotiris E. Pratsinis and colleagues at ETH Zurich in Switzerland explain that everyone has a little bit of acetone in their breath. But people with Type I diabetes release unusually high levels of the chemical when they exhale. If they have diabetic ketoacidosis, a dangerous buildup of acetone in the blood, they exhale even-larger amounts of acetone.

Pratsinis' team built an extremely sensitive acetone detector by directly depositing from a flame plume a thin film of semiconducting, mixed ceramic nanoparticles between a set of gold electrodes. The device acts like an electrical resistor. When it gets hit with a puff of acetone-filled air, its resistance drops, allowing more electricity to pass between the electrodes. If a diabetic were to breathe on the sensor, its resistance would suddenly drop. When a healthy person exhales onto the nanoparticles, their resistance will not change very much. Pratsinis' team found this new sensor can detect acetone in extremely moist air, an attribute that is critical for any breath test. It is sensitive enough to detect acetone at 20 parts per billion, a concentration that is 90 times lower than the level at which it can be found in the breath of diabetic patients.

Analytical Chemistry: "Si:WO₃ Sensors for Highly Selective Detection of Acetone for Easy Diagnosis of Diabetes by Breath Analysis" [Anal. Chem., 2010, 82 (9), pp 3581?3587; DOI: 10.1021/ac902695n].

Mercury levels are increasing in popular species of game fish in Lake Erie

Scientists are reporting that mercury levels in a popular species of game fish in Lake Erie are increasing after two decades of steady decline. The study, the most comprehensive to date on mercury levels in Great Lakes fish, is in ACS' Environmental Science & Technology, a semi-monthly journal.

Satyendra Bhavsar and colleagues note that the Great Lakes is the largest group of freshwater lakes in the world. The lakes are of significant economic importance to the United States and Canada due to the area's $7 billion fishing industry. High levels of mercury in fish can potentially cause adverse health effects in people. Although government regulations and improved emissions control technologies have greatly reduced mercury emissions in the environment, their impact on mercury levels in Great Lakes fish is unclear.

The scientists studied mercury levels in 5807 fish samples collected from the lakes between the 1970s and 2007. The samples included lake trout and walleye, two of the most common species of game fish caught in the region. The researchers found that mercury levels in the fish steadily declined from the mid-1970s to 2007 in the upper Great Lakes (Superior and Huron). In recent years (between 1990 and 2007), however, the mercury concentrations leveled-off in Lake Ontario walleye but appear to be increasing in Lake Erie walleye. The mercury increases in Lake Erie walleye are likely caused by a combination of factors, including modifications in Lake Erie's foodweb due to invasions of dreissenid mussels and round goby, the scientists suggest.

Environmental Science & Technology: "Changes in Mercury Levels in Great Lakes Fish Between 1970s and 2007" [Environ. Sci. Technol., 2010, 44 (9), pp 3273?3279; DOI: 10.1021/es903874x].

Biodiesel from sewage sludge within pennies a gallon of being competitive

Existing technology can produce biodiesel fuel from municipal sewage sludge that is within a few cents a gallon of being competitive with conventional diesel refined from petroleum, according to an article in ACS' Energy & Fuels, a bi-monthly journal. Sludge is the solid material left behind from the treatment of sewage at wastewater treatment plants.

David M. Kargbo points out in the article that demand for biodiesel has led to the search for cost-effective biodiesel feedstocks, or raw materials. Soybeans, sunflower seeds and other food crops have been used as raw materials but are expensive. Sewage sludge is an attractive alternative feedstock - the United States alone produces about seven million tons of it each year. Sludge is a good source of raw materials for biodiesel. To boost biodiesel production, sewage treatment plants could use microorganisms that produce higher amounts of oil, Kargbo says. That step alone could increase biodiesel production to the 10 billion gallon mark, which is more than triple the nation's current biodiesel production capacity, the report indicates.

The report, however, cautions that to realize these commercial opportunities, huge challenges still exist, including challenges from collecting the sludge, separation of the biodiesel from other materials, maintaining biodiesel quality, soap formation during production, and regulatory concerns.

With the challenges addressed, "Biodiesel production from sludge could be very profitable in the long run," the report states. "Currently the estimated cost of production is $3.11 per gallon of biodiesel. To be competitive, this cost should be reduced to levels that are at or below [recent] petro diesel costs of $3.00 per gallon."

Energy & Fuels: "Biodiesel Production from Municipal Sewage Sludges" [2010, 24 (5), pp 2791?2794; DOI: 10.1021/ef1001106].

The fungus among us:

An eco-friendly way of decomposing BPA-containing plastic

Just as cooking helps people digest food, pretreating polycarbonate plastic - source of a huge environmental headache because of its bisphenol A (BPA) content - may be the key to disposing of the waste in an eco-friendly way, scientists have found. Their new study is in ACS' Biomacromolecules, a monthly journal.

Mukesh Doble and Trishul Artham note that manufacturers produce about 2.7 million tons of plastic containing BPA each year. Polycarbonate is an extremely recalcitrant plastic, used in everything from screwdriver handles to eyeglass lenses, DVDs, and CDs. Some studies have suggested that the BPA may have a range of adverse health effects, sparking the search for an environmentally safe way of disposing of waste plastic to avoid release of BPA.

The scientists pretreated polycarbonate with ultraviolet light and heat and exposed it to three kinds of fungi - including the fabled white-rot fungus, used commercially for environmental remediation of the toughest pollutants. The scientists found that fungi grew better on pretreated plastic, using its BPA and other ingredients as a source of energy and breaking down the plastic. After 12 months, there was almost no decomposition of the untreated plastic, compared to substantial decomposition of the pretreated plastic, with no release of BPA.

Biomacromolecules: "Biodegradation of Physiochemically Treated Polycarbonate by Fungi" [2010, 11 (1), pp 20?28; DOI: 10.1021/bm9008099].

New plastic-like materials may say 'shhhh' to hush disease-causing microbes

Scientists are reporting success in a first attempt to silence the biochemical conversations that disease-causing bacteria use to marshal their forces and cause infections. In a study in ACS' monthly journal, Biomacromolecules, they describe use of specially designed plastic-like materials to soak up the substances that bacteria produce and pass to one another as messages.

Elena Piletska and colleagues point out that more and more disease-causing bacteria are developing resistance to the effects of antibiotics. The problem has sparked a global scientific quest for new antibiotics, and totally new approaches for dealing with bacteria that have caused millions of deaths throughout human history. One increasingly promising approach, they explain, blocks the chemical signals bacteria use to launch infection, a signaling process called "quorum sensing."

The scientists designed special plastics, similar to those dentists use to repair damaged teeth, to capture signaling molecules in laboratory experiments and thwart microbes' attempts to start an infection. The plastics also reduced the ability of the bacteria to form biofilms. Bacteria form these slimy layers inside medical tubing, water supply pipes, and other surfaces and use them as a refuge to grow and multiply.

Biomacromolecules: "Attenuation of Vibrio fischeri Quorum Sensing Using Rationally Designed Polymers" [DOI: 10.1021/bm901451j; Publication Date (Web): March 15, 2010].

Recycling tiny trash: cigarette butts

A new study suggests expanding community recycling programs beyond newspapers, beverage containers, and other traditional trash to include an unlikely new potential treasure: Cigarette butts. Terming this tiny trash "one of the most ubiquitous forms of garbage in the world," the study describes discovery of a way to reuse the remains of cigarettes to prevent steel corrosion that costs oil producers millions of dollars annually. It appears in ACS' Industrial & Engineering Chemistry Research, a bi-weekly journal.

Jun Zhao and colleagues cite one estimate that 4.5 trillion cigarette butts find their way into the environment each year. Studies show that cigarette butts are more than an eyesore. They contain toxins that can kill fish and harm the environment in other ways. Recycling could solve those problems, but finding practical uses for cigarette butts has been difficult.

The scientists showed that extracts of cigarette butts in water, applied to a type of steel (N80) widely used in the oil industry, protected the steel from rusting even under the harsh conditions, preventing costly damage and interruptions in oil production. They identified nine chemicals in the extracts, including nicotine, which appear to be responsible for this anti-corrosion effect.

Industrial & Engineering Chemistry Research: "Cigarette Butts and Their Application in Corrosion Inhibition for N80 Steel at 90?C in a Hydrochloric Acid Solution" [Ind. Eng. Chem. Res., 2010, 49 (8), pp 3986?3991; DOI: 10.1021/ie100168s].

Schizophrenia drugs raise the volume of a key signaling system in the brain

All the major groups of medications for schizophrenia turn up the volume of a brain signal known to be muted in individuals with this psychiatric disorder - a signal that also can be influenced by diet. "This is the first example of a common but specific molecular effect produced by all antipsychotic drugs in any biological system," scientists note in the current edition of ACS Chemical Neuroscience, a monthly journal.

In the report, Eric J. Aamodt and colleagues explained that scientists know little about how antipsychotic drugs work, aside from the drugs' effects on one signaling chemical called dopamine. New studies, for instance, suggested that medications like olanzapine, quetiapine, and clozapine also affect other signaling systems in the brain. These systems, including one termed the Akt signaling pathway, influence behavior by regulating communication between brain cells. To fill those gaps in knowledge, the scientists turned to genetically modified forms of a worm, C. elegans, often used as a stand-in for people in such research. The tiny creatures were wired to glow green to show activity of Akt, a signal that is too quiet in schizophrenic brains.

They found that all of the 13 antipsychotic drugs tested, representative of all major categories of antipsychotic medications, helped the worms maintain their characteristic green glow. The results highlight the importance of Akt signaling in schizophrenia, suggesting that medications or other approaches that increase Akt signaling might help to alleviate the symptoms of schizophrenia. Other labs have identified certain dietary measures that may also increase Akt signaling.

Chemical Neuroscience: "Antipsychotic Drugs Activate the C. elegans Akt Pathway via the DAF-2 Insulin/IGF-1 Receptor" [ACS Chem. Neurosci.;DOI: 10.1021/cn100010p].