Discover the most talked about and latest scientific content & concepts.

Journal: Environmental health : a global access science source


The Germanwings Flight 9525 crash has brought the sensitive subject of airline pilot mental health to the forefront in aviation. Globally, 350 million people suffer from depression-a common mental disorder. This study provides further information on this important topic regarding mental health especially among female airline pilots. This is the first study to describe airline pilot mental health-with a focus on depression and suicidal thoughts-outside of the information derived from aircraft accident investigations, regulated health examinations, or identifiable self-reports, which are records protected by civil aviation authorities and airline companies.

Concepts: Psychology, Mental disorder, Suicide, Aircraft, Aviator, Airline, International Civil Aviation Organization, Civil aviation


BACKGROUND: Endocrine disrupting chemicals and carcinogens, some of which may not yet have been classified as such, are present in many occupational environments and could increase breast cancer risk. Prior research has identified associations with breast cancer and work in agricultural and industrial settings. The purpose of this study was to further characterize possible links between breast cancer risk and occupation, particularly in farming and manufacturing, as well as to examine the impacts of early agricultural exposures, and exposure effects that are specific to the endocrine receptor status of tumours. METHODS: 1006 breast cancer cases referred by a regional cancer center and 1146 randomly-selected community controls provided detailed data including occupational and reproductive histories. All reported jobs were industry- and occupation-coded for the construction of cumulative exposure metrics representing likely exposure to carcinogens and endocrine disruptors. In a frequency-matched case–control design, exposure effects were estimated using conditional logistic regression. RESULTS: Across all sectors, women in jobs with potentially high exposures to carcinogens and endocrine disruptors had elevated breast cancer risk (OR = 1.42; 95% CI, 1.18-1.73, for 10 years exposure duration). Specific sectors with elevated risk included: agriculture (OR = 1.36; 95% CI, 1.01-1.82); bars-gambling (OR = 2.28; 95% CI, 0.94-5.53); automotive plastics manufacturing (OR = 2.68; 95% CI, 1.47-4.88), food canning (OR = 2.35; 95% CI, 1.00-5.53), and metalworking (OR = 1.73; 95% CI, 1.02-2.92). Estrogen receptor status of tumors with elevated risk differed by occupational grouping. Premenopausal breast cancer risk was highest for automotive plastics (OR = 4.76; 95% CI, 1.58-14.4) and food canning (OR = 5.70; 95% CI, 1.03-31.5). CONCLUSIONS: These observations support hypotheses linking breast cancer risk and exposures likely to include carcinogens and endocrine disruptors, and demonstrate the value of detailed work histories in environmental and occupational epidemiology.

Concepts: Cancer, Breast cancer, Oncology, Estrogen, Endocrinology, Estrogen receptor, Endocrine system, Endocrine disruptor


The broad-spectrum herbicide glyphosate (common trade name “Roundup”) was first sold to farmers in 1974. Since the late 1970s, the volume of glyphosate-based herbicides (GBHs) applied has increased approximately 100-fold. Further increases in the volume applied are likely due to more and higher rates of application in response to the widespread emergence of glyphosate-resistant weeds and new, pre-harvest, dessicant use patterns. GBHs were developed to replace or reduce reliance on herbicides causing well-documented problems associated with drift and crop damage, slipping efficacy, and human health risks. Initial industry toxicity testing suggested that GBHs posed relatively low risks to non-target species, including mammals, leading regulatory authorities worldwide to set high acceptable exposure limits. To accommodate changes in GBH use patterns associated with genetically engineered, herbicide-tolerant crops, regulators have dramatically increased tolerance levels in maize, oilseed (soybeans and canola), and alfalfa crops and related livestock feeds. Animal and epidemiology studies published in the last decade, however, point to the need for a fresh look at glyphosate toxicity. Furthermore, the World Health Organization’s International Agency for Research on Cancer recently concluded that glyphosate is “probably carcinogenic to humans.” In response to changing GBH use patterns and advances in scientific understanding of their potential hazards, we have produced a Statement of Concern drawing on emerging science relevant to the safety of GBHs. Our Statement of Concern considers current published literature describing GBH uses, mechanisms of action, toxicity in laboratory animals, and epidemiological studies. It also examines the derivation of current human safety standards. We conclude that: (1) GBHs are the most heavily applied herbicide in the world and usage continues to rise; (2) Worldwide, GBHs often contaminate drinking water sources, precipitation, and air, especially in agricultural regions; (3) The half-life of glyphosate in water and soil is longer than previously recognized; (4) Glyphosate and its metabolites are widely present in the global soybean supply; (5) Human exposures to GBHs are rising; (6) Glyphosate is now authoritatively classified as a probable human carcinogen; (7) Regulatory estimates of tolerable daily intakes for glyphosate in the United States and European Union are based on outdated science. We offer a series of recommendations related to the need for new investments in epidemiological studies, biomonitoring, and toxicology studies that draw on the principles of endocrinology to determine whether the effects of GBHs are due to endocrine disrupting activities. We suggest that common commercial formulations of GBHs should be prioritized for inclusion in government-led toxicology testing programs such as the U.S. National Toxicology Program, as well as for biomonitoring as conducted by the U.S. Centers for Disease Control and Prevention.

Concepts: Epidemiology, Agriculture, Animal testing, Toxicology, Carcinogen, Herbicide, Glyphosate, Roundup


The ratio of male to female offspring at birth may be a simple and non-invasive way to monitor the reproductive health of a population. Except in societies where selective abortion skews the sex ratio, approximately 105 boys are born for every 100 girls. Generally, the human sex ratio at birth is remarkably constant in large populations. After the Chernobyl nuclear power plant accident in April 1986, a long lasting significant elevation in the sex ratio has been found in Russia, i.e. more boys or fewer girls compared to expectation were born. Recently, also for Cuba an escalated sex ratio from 1987 onward has been documented and discussed in the scientific literature.

Concepts: Male, Reproduction, Female, Demography, Population, Chernobyl disaster, Gender, Sex ratio


Many populations have been exposed to environmental lead from paint, petrol, and mining and smelting operations. Lead is toxic to humans and there is emerging evidence linking childhood exposure with later life antisocial behaviors, including delinquency and crime. This study tested the hypothesis that childhood lead exposure in select Australian populations is related to subsequent aggressive criminal behaviors.

Concepts: Biology, Environment, Natural environment, Crime, Lead, Antisocial personality disorder, Juvenile delinquency


Women have elevated rates of thyroid disease compared to men. Environmental toxicants have been implicated as contributors to this dimorphism, including polybrominated diphenyl ethers (PBDEs), flame retardant chemicals that disrupt thyroid hormone action. PBDEs have also been implicated in the disruption of estrogenic activity, and estrogen levels regulate thyroid hormones. Post-menopausal women may therefore be particularly vulnerable to PBDE induced thyroid effects, given low estrogen reserves. The objective of this study was to test for an association between serum PBDE concentrations and thyroid disease in women from the United States (U.S.), stratified by menopause status.

Concepts: Hormone replacement therapy, Hormone, Menopause, Estrogen, Luteinizing hormone, Thyroid hormone, Flame retardant, Flame retardants


BACKGROUND: Flame retardant chemicals are used in materials on airplanes to slow the propagation of fire. These chemicals migrate from their source products and can be found in the dust of airplanes, creating the potential for exposure. METHODS: To characterize exposure to flame retardant chemicals in airplane dust, we collected dust samples from locations inside 19 commercial airplanes parked overnight at airport gates. In addition, hand-wipe samples were also collected from 9 flight attendants and 1 passenger who had just taken a cross-country (USA) flight. The samples were analyzed for a suite of flame retardant chemicals. To identify the possible sources for the brominated flame retardants, we used a portable XRF analyzer to quantify bromine concentrations in materials inside the airplanes. RESULTS: A wide range of flame retardant compounds were detected in 100% of the dust samples collected from airplanes, including BDEs 47, 99, 153, 183 and 209, tris(1,3-dichloro-isopropyl)phosphate (TDCPP), hexabromocyclododecane (HBCD) and bis-(2-ethylhexyl)-tetrabromo-phthalate (TBPH). Airplane dust contained elevated concentrations of BDE 209 (GM: 500 ug/g; range: 2,600 ug/g) relative to other indoor environments, such as residential and commercial buildings, and the hands of participants after a cross-country flight contained elevated BDE 209 concentrations relative to the general population. TDCPP, a known carcinogen that was removed from use in children’s pajamas in the 1970’s although still used today in other consumer products, was detected on 100% of airplanes in concentrations similar to those found in residential and commercial locations. CONCLUSION: This study adds to the limited body of knowledge regarding exposure to flame retardants on commercial aircraft, an environment long hypothesized to be at risk for maximum exposures due to strict flame retardant standards for aircraft materials. Our findings indicate that flame retardants are widely used in many airplane components and all airplane types, as expected. Most flame retardants, including TDCPP, were detected in 100% of dust samples collected from the airplanes. The concentrations of BDE 209 were elevated by orders of magnitude relative to residential and office environments.

Concepts: Fire retardant, Flame retardant, Decabromodiphenyl ether, Bromine, Brominated flame retardant, Flame retardants, Hexabromocyclododecane, Aircraft


In their new paper, Bellanger and coauthors show substantial economic impacts to the EU from neurocognitive impairment associated with methylmercury (MeHg) exposures. The main source of MeHg exposure is seafood consumption, including many marine species harvested from the global oceans. Fish, birds and other wildlife are also susceptible to the impacts of MeHg and already exceed toxicological thresholds in vulnerable regions like the Arctic. Most future emissions scenarios project a growth or stabilization of anthropogenic mercury releases relative to present-day levels. At these emissions levels, inputs of mercury to ecosystems are expected to increase substantially in the future, in part due to growth in the legacy reservoirs of mercury in oceanic and terrestrial ecosystems. Seawater mercury concentration trajectories in areas such as the North Pacific Ocean that supply large quantities of marine fish to the global seafood market are projected to increase by more than 50% by 2050. Fish mercury levels and subsequent human and biological exposures are likely to also increase because production of MeHg in ocean ecosystems is driven by the supply of available inorganic mercury, among other factors. Analyses that only consider changes in primary anthropogenic emissions are likely to underestimate the severity of future deposition and concentration increases associated with growth in mercury reservoirs in the land and ocean. We therefore recommend that future policy analyses consider the fully coupled interactions among short and long-lived reservoirs of mercury in the atmosphere, ocean, and terrestrial ecosystems. Aggressive anthropogenic emission reductions are needed to reduce MeHg exposures and associated health impacts on humans and wildlife and protect the integrity of one of the last wild-food sources globally. In the near-term, public health advice on safe fish consumption choices such as smaller species, younger fish, and harvests from relatively unpolluted ecosystems is needed to minimize exposure risks.

Concepts: Fish, United States, Atlantic Ocean, Pacific Ocean, Ocean, Seafood, Arctic Ocean, Oceans


BACKGROUND: Bronchial asthma is one of the most prevalent diseases in Arab children. Environmental pollution has been suggested to be considered causative of asthma, nasal symptoms and bronchitis in both children and adult. The objectives of this study were to evaluate the association between serum polycyclic aromatic hydrocarbons (PAHs) levels, asthma and allergic outcomes among Saudi children aged up to 15 yrs. We hypothesized that increased serum PAHs are associated with allergy, asthma, or respiratory symptoms. METHODS: A total of 195 Saudi children (98 asthma pediatric patients and 97 healthy controls) were randomly selected from the Riyadh Cohort Study for inclusion. The diagnosis of Asthma was based on established pediatric diagnosis and medications taken. RESULTS: Asthma related markers showed highly significant differences between children with and without asthma. Thus IgE, resistin and IL-4 were significantly increased (p 0.004, 0.001 and 0.003, respectively) in children with asthma compared with non-asthma control subjects. GMCSF, IFN-gamma, IL-5, IL-8 and IL-10, on the other hand, were significantly decreased in children with asthma (p 0.003, 0.03, 0.001, 0.004 and 0.03, respectively). Strong associations between serum PAHs levels and biomarkers of childhood asthma were detected in Arabic children. Data confirmed the role of naphthalene, 4H-cyclobenta[def]phenanthrene, 1,2-benzanthracene, chrysene and benzo(e)acephenanthrylene in childhood asthma; levels of these PAHs were correlated with asthma related biomarkers including IgE, resistin, GMCSF and IFN-gamma as well as IL-4, IL-5, IL-8 and IL-10 cytokines. CONCLUSIONS: This data highlight the pivotal role of specific PAHs in childhood asthma.

Concepts: Asthma, Allergy, Polycyclic aromatic hydrocarbon, Benzene, Hydrocarbon, Aromaticity, Naphthalene, Chrysene


Increased concern for potential health and environmental impacts of chemicals, including nanomaterials, in consumer products is driving demand for greater transparency regarding potential risks. Chemical hazard assessment is a powerful tool to inform product design, development and procurement and has been integrated into alternative assessment frameworks. The extent to which assessment methods originally designed for conventionally-sized materials can be used for nanomaterials, which have size-dependent physical and chemical properties, have not been well established. We contracted with a certified GreenScreen profiler to conduct three GreenScreen hazard assessments, for conventional silver and two forms of nanosilver. The contractor summarized publicly available literature, and used defined GreenScreen hazard criteria and expert judgment to assign and report hazard classification levels, along with indications of confidence in those assignments. Where data were not available, a data gap (DG) was assigned. Using the individual endpoint scores, an aggregated benchmark score (BM) was applied.

Concepts: Risk, Chemistry, Chemical substance, Chemical element, Assessment, Scores, Physical property, The Contractor