~dGossip
~tAll Diesel Exhaust Is Not the Same: Engine Load Alters Toxicity
~w2011-08-03
After years of extensive research on the health impacts of diesel engine exhaust (DEE), important information gaps still remain. Among these gaps are differences in the composition of DEE created when an engine operates under different load conditions (i.e., how hard the engine is working) as well as the health effects associated with various exhaust compositions. Some studies have evaluated exhaust products and health effects under one load condition or another, or with varying operating conditions during the same engine run cycle. However, until now none have evaluated different load conditions in the same study, then looked at health effects caused by the separate exhaust products.The new study, published in the journal Environmental Health Perspectives,analysed the composition of DEE generated from a single-cylinder diesel generator operating under full (100%) or partial (55%) load. In addition, the researchers evaluated several health end points in two strains of mice that inhaled the two resulting exhaust products, which varied substantially in composition.The particulate matter (PM) concentrations in the exhaust products were similar to those found in certain occupational and high ambient outdoor settings. Under partial load, the PM constituent had higher organic carbon, ammonium, sulphate, and nitrate mass, lower elemental (black) carbon mass, and smaller particle size, compared with full-load exhaust. Vapour phase partial-load exhaust had a greater mass of carbon monoxide and nonmethane volatile organic compounds, a higher percentage of naphthalenes, and a lower percentage of alkanes.Male C57B1/6 mice exposed to full-load exhaust had significantly more lung inflammation, as indicated through heme oxygenase-1 expression, compared with mice exposed to partial-load exhaust. These mice also demonstrated greater susceptibility to viral lung inflammation and epithelial damage and were much slower in clearing the virus from their lungs. However, mice exposed to partial-load exhaust had lower levels of two other inflammation indicators, interferon-γ and tumor necrosis factor-α, than either control mice or those exposed to full-load exhaust.In male ApoE– / – mice, one measure of cardiovascular toxicity—reduction in heart rate—occurred significantly faster following exposure to partial-load exhaust compared with full-load exposure. Furthermore, partial-load exhaust was linked with a rapid increase in T-wave area, another indicator of cardiovascular toxicity, which was not affected by exposure to full-load exhaust.The researchers concluded that the typical practice of evaluating DEE health effects based solely on the PM mass concentration of the exhaust is misleading. Instead, they recommended researchers carefully analyse and describe the DEE compositions they use in their studies so different bodies of work can be more accurately compared.
Environmental Phealth Perspectives, 1 August 2011
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~dGossip
~tBacteria rejoice: study identifies safe solvents
~w2011-08-03
Chemists took a first step towards designing a more environmentally-friendly solvent known as ionic liquids by identifying those that won't kill the bacteria used to transform raw materials into useable products. For the first time, a large number of the new types of solvents were tested on the E. coli bacteria strains that are widely used in industry. Many of them did not harm the bacteria and may be hopeful candidates for industry. The popularity of ionic liquids is growing as researchers eye them to replace toxic, smelly and polluting organic solvents currently used to produce all manner of chemicals and consumer products. To make chemicals, solvents are commonly required. Solvents dissolve gases, solids or liquids into a solution. They can help to bring the reacting chemicals in contact, separate the products from reactants and sometimes even speed up the chemical reaction. Unfortunately, many solvents are toxic, volatile – they evaporate quickly – and/or flammable. It is therefore important to perform reactions without solvents, if possible, or use more benign solvents. Ionic liquids are a relatively new class of solvents. They are salts – a designation for chemicals made up of both a positively and a negatively charged component– that are liquid at low temperatures, unlike common salts such as kitchen salt. Bulky positive and negative groups that make up the ionic salts hinder their packing into a solid crystal. Thus, they stay liquid to much lower temperatures – even room temperature. People are interested in using ionic liquids because they have extremely low volatility resulting in virtually no vapour emissions. The properties of these ionic liquids (solvating power, melting point, water solubility) can also be easily varied by changing the positive and negative groups. Researchers wish to use ionic liquids for industrial biotransformation – a process in which bacteria produce chemical products. The most commonly known biotransformation is sugar fermenting into ethanol – the way beer and wine are produced. However, fuel from renewable resources - i.e. biofuel - and even valuable chemicals can also be made this way. Biotransformation has the potential to have a much lower impact on the environment than pure chemical reactions. During the current study, the researchers from the United Kingdom, tested the toxicity of 90 different ionic liquids in the laboratory using the bacterium Escheria coli (E. coli).E. coli regularly receives negative press attention because it can cause food poisoning in people. However, it is also used frequently in industrial biotransformation
The major problem in biotransformations is that the produced chemicals are sometimes toxic to the bacteria. So as the bacteria become more efficient at producing the wanted product, they become less efficient because they die. And this is where ionic liquids can play an important role. By using an ionic liquid in which the reaction product, which is toxic to the bacteria, is soluble, the product could be extracted from the aqueous broth of bacteria before it accumulates too much, becomes too toxic and kills the bacteria.This plan requires ionic liquids that are not toxic to the bacteria. The work described here begins to identify the nontoxic varieties by looking at the effect of the different ionic liquids on cell viability and growth rates. The researchers examined in high throughput tests ionic fluids that can dissolve (miscible) or remain undissolved (immiscible) in water.Various ionic liquids were found to be non-toxic towards E. coli. There were both water miscible and immiscible ionic liquids that did not show toxicity. Importantly, the ionic liquids displayed similar toxic behaviour based on their specific negative and positive chemical groups.With this information, it is possible to start to predict the toxicity of ionic liquids towards E. coli if they contain the same charged groups as those used in this study. Surprisingly, it was also possible to prepare a type of ionic liquid called quaternary ammonium salt ionic liquids that were non-toxic to E. coli by changing the negative ion attached to it. This is a remarkable result since quaternary ammonium salts are being widely investigated for use as antibacterial agents on hard surfaces.Many types of ionic liquids were compatible with the bacteria E. coli and could be candidates for industrial uses that transform starting materials into products.The results are very important because the toxicity trends prove that it is possible to start to rationally design ionic liquids.The study shows it is possible to make a certain ionic liquid that has the toxicity effect that is required by choosing the positive and negative ions that it is made from. It is already possible to adjust physical parameters, such as melting point, freezing point and solvating power, i.e. the amount of a specific chemical that can be dissolved. This work thus adds another parameter that can be manipulated, adding another benefit to the use of ionic liquids. The recent study is the first in a range of studies that will need to be performed to isolate which ionic liquids will perform the best. While 90 ionic liquids is a large number, more ionic liquids will need to be studied to help form a much better idea of their toxicity towards E. coli and other bacteria useful to industry.
Environmental Health News, 2 August 2011
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~dGossip
~tEU validates test methods for sports drinks contaminated with plasticizer
~w2011-08-03
The European Commission's Joint Research Centre (JRC) has published three methods to detect an illegal clouding agent that was found earlier this year in sports drinks imported from Taiwan. Producers of sports drinks, jelly and fruit pulps commonly use a palm-oil based product to obtain a cloudy appearance, but in the Taiwanese incident, manufacturers had instead used bis-(2-ethylhexyl) phthalate (DEHP) and - in one case - di-iso-nonyl phthalate (DINP). The new methods have been validated for a DEHP range of 3 mg/kg to 100 mg/kg in sports drinks. All three analytical methods, or standard operating procedures (SOPs), are based on different combinations of chromatography and mass spectrometry techniques. In late May, the Taiwanese authorities warned that significant amounts of phthalates had been illegally added to certain categories of sports drinks. The contaminated products were exported on a significant scale to Canada, the US, Malaysia and China and the incident caused major commercial ructions in the markets around South East Asia. ACommission spokesman said that the new methods would provide reliable tools for regulators and other interested parties in any future incidents. DEHP and DINP are believed to affect reproductive performance and fertility and have been linked to developmental problems in children. They are commonly used as plasticisers, but are prohibited for use in the production of food. Furthermore, they are restricted in plastic toys and childcare products within the EU. The latest incident blew up when the Taiwanese Food and Drug Administration published the names of 879 products from more than 300 producers that contained high amounts of phthalates. More than 200 products from 34 producers were exported to 22 countries.
Nutra Ingredients, 1 August 2011
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~dGossip
~tNew Device Measures Atmospheric Isocyanic Acid
~w2011-08-03
A new study is the first to measure isocyanic acid (chemically HNCO), a contaminant linked to cataracts and heart disease, in the atmosphere. The discovery was made by researchers at the National Oceanic and Atmospheric Administration (NOAA) who designed a new detection system to measure HNCO in environments where conventional methods could not previously detect it.Study leader James Roberts and colleagues developed a specialised negative-ion proton-transfer chemical ionisation mass spectrometer to measure organic acids emitted by wildfires. They tested the instrument on brush and tree branches burned in a test chamber, which generated levels of HNCO reaching 600 ppbv. Next they used the device on air samples collected in Boulder, Colorado, during the 2010 Fourmile Canyon wildfire and ambient air samples collected in downtown Los Angeles, California. These samples yielded HNCO concentrations up to 200 pptv and 100 pptv, respectively. No wildfires were burning near Los Angeles at the time, so “we assume isocyanic acid came from vehicle exhaust or photochemical reactions known to make it,” Roberts says. In addition, the researchers observed HNCO in laboratory samples of cigarette smoke but noted “the levels were too high for us to quantify with the . . . instrument configured in the ambient measurement mode.” Drawing on a surrogate pyrolysis study that found nearly all the urea in tobacco decomposes to HNCO during burning, the researchers calculated mainstream cigarette smoke may contain 40–140 ppmv HNCO. Urea is added to cigarettes to enhance flavour. In addition, urea is used in selective catalytic reduction systems to break down toxic nitrogen oxides (NOX) in diesel exhaust into nitrogen and water. Roberts wants to measure HNCO emitted by these systems, which the European Union mandates for heavy-duty diesel trucks; a similar law is pending in California. “In trying to solve the problem of NOX we could be increasing HNCO,” Roberts says.The health effects of chronic exposure to environmental HNCO are unknown, although Roberts and colleagues note the concentrations they measured in smoke “cause carbamylation at physiologically significant levels.” In carbamylation, cyanate binds the amino acid lysine in proteins to form homocitrulline. Stanley Hazen, section head of Preventive Cardiology and Rehabilitation at the Cleveland Clinic, found that high blood levels of homocitrulline are a strong predictor of heart disease, especially in smokers, offering a possible mechanism linking smoking to atherosclerosis.“We assumed the exogenous source of cyanate in our study was smoking,” Hazen says. Now Roberts’ study suggests HNCO from air pollution also may increase cardiovascular disease risk. “Any degree of carbamylation has potential to be harmful,” Hazen says, although the levels required to raise cardiac and other health risks remain to be determined.
Environmental Health Perspectives, 1 August 2011
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~dGossip
~tResearchers to study spill's effect on women
~w2011-08-03
In a new study, researchers from TulaneUniversity's School of Public Health and Tropical Medicine examined the health effects on pregnant women and women of reproductive age in Louisiana's coastal parishes caused by the Deepwater Horizon oil spill. The National Institute of Environmental Health Sciences provided $6.5 million to do the work. It's the first long-term study to examine a major spill's effects on pregnant women and women's health, said Dr. Maureen Lichtvelt, chairwoman of environmental policy for Tulane and the study's lead researcher.“Pregnant women are always a population of concern when there are environmental exposures,” Lichtvelt said. “The developing foetus may be vulnerable to even small doses of contaminants.” In addition, the study will examine the impact of repeated disasters on pregnancy outcomes and women's health.The study will follow 500 pregnant and 500 women of reproductive age over five years. It will look at women in Lafourche, Terrebonne, Orleans, Plaquemines, Jefferson and St. Bernard parishes.The National Institutes of Health, a federal research program, is conducting a long-term study to monitor the health of tens of thousands of oil-spill workers and volunteers. Three other schools also received grants totalling more than $17 million to study other oil-spill health issues, including an independent study into seafood safety.Wilma Subra, an environmental toxicologist from New Iberia who's been studying the impact of oil on health and contamination in seafood, soil and human blood, said there's a possibility the oil spill is linked to an increased number of miscarriages. Furthermore, some worry exposure to oil could cause a higher number of birth defects, she said.Women could have been exposed to oil through air-borne toxins, by eating contaminated seafood or coming in contact with oil-contaminated water or land, she said. The women could have also been exposed when washing the clothes of family members involved with the clean up.Researchers will try to quantify women's exposure to oil, but it may be impossible to link exposure directly to the BP oil spill, Lichtvelt said.“Ideally you'd want to know what happened before the oil spill so you can compare,” she said. “We don't have that kind of information.”The study will also look at how stress from repeated disasters affects women, such as whether some delay having children or decide against a family.“To our knowledge, this is also the first study to examine maternal stress and anxiety related to a major oil spill and the associated effects on birth outcomes, foetal health and family planning behaviour,” Lichtvelt said.Finally, the study will determine whether health outreach and mobile-health technology can improve pregnancy outcomes of women in vulnerable areas such as coastal Louisiana.
Daily Comet, 1 August 2011
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~dGossip
~tSmokers' lung damage lingers
~w2011-08-03
According to a new study by researchers from the University of Sydney, cigarette smoke exposure fundamentally alters airway tissue in people with chronic obstructive pulmonary disease (COPD), and even while other aspects of health improve, the lung damage lasts long after a smoker quits. COPD is the fifth leading cause of death in Australia, taking more lives than skin cancer and breast cancer combined, said the lead researcher David Krimmer of the Woolcock Institute of Medical Research at the University of Sydney. Working with senior investigator Dr Brian Oliver, PhD candidate Mr Krimmer found smoking lays the groundwork for airway thickening, and even precipitates precancerous changes in cell proliferation that may be self-perpetuating long after cigarette smoke exposure ends. "We have demonstrated for the first time that the extracellular matrix (ECM) produced by fibroblasts following stimulation with cigarette smoke extract is functionally different than non-exposed ECM, and that the cigarette smoke itself may prime the airways in such a way to create an environment whereby airway remodelling is encouraged," they write in an online paper, prior to publication in the American Journal of Respiratory Cell and Molecular Biology. COPD is projected to be the third-leading cause of death worldwide by 2020, and is characterised by emphysematous destruction of the alveoli and thickening of the airway wall. The primary cause is chronic exposure to air pollution, most often cigarette smoke. During the new study, the researchers examined the response of human lung tissue from donors with and without COPD to cigarette smoke extract (CSE). They found CSE exposure led to changes in the tissue of donors with COPD over the tissue of individuals without COPD. Similarly, they found CSE increased levels of perlecan — a protein associated with tumour growth and angiogenesis — in COPD lung tissue. These findings demonstrate cigarette smoke has the capacity to directly change the make-up of the airways. "This will change the way researchers think about the development of fibrosis in COPD," said Mr Krimmer. "We have known for a long time that development of fibrosis is irreversible in people with COPD. Our findings suggest that cigarette smoking alters the lung composition in such a way that fibrosis becomes self-perpetuating," explained Mr Krimmer. "Cigarette smoking is obviously bad for everyone. However, in light of our findings, cigarette smoking is likely to be especially dangerous in people with pre-existing COPD," he said. "It is our hope that further research on how and why this occurs will result in viable therapeutic targets for reducing the detrimental airway changes underlying COPD."