Neurological effects of traffic pollution
The link between air pollution and respiratory disorders is quite well known [1]. The association between air pollution and cardiovascular diseases has been reviewed in a previous post.
The latest research on air pollution looks into the neurological effects with following results:
Air pollution and brain function [2]
Exposure to diesel fumes triggers a stress response in the human brain. Researchers were able to demonstrate this using dilute diesel exhaust fumes (300 µg/m3) as model for ambient particulate matter exposure and monitoring brain activities by quantitative encephalogram (QEEG). In this double-blind randomized crossover study, those exposed to diesel exhaust showed a significant increase in the median power frequency of the QEEG after 30 minutes of exposure. This functional response in the brain continued to rise with longer exposure.
Air pollution and children`s IQ [3]
Children exposed to traffic-related pollution perform poorly in intelligence and memory tests compared those who breathe cleaner air. This prospective birth cohort study looked into children`s exposure to black carbon, a particulate matter component generated by traffic vehicles. Heavy exposure to black carbon translated to drops in averages scores in intelligence, vocabulary, memory and learning scales and indices. “Higher levels of black carbon predicted decreased cognitive function across assessments of verbal and nonverbal intelligence and memory constructs.”
It is speculated that “ultrafine” or “nanoparticles” found in the environment translocate to the brain and cause increased oxidative stress and brain inflammation.
Sources:
1 Andersen et al. Ambient Air Pollution Triggers Wheezing Symptoms in Infants. Thorax.Published Online First: 11 February 2008
2. Cruts et al. Exposure to diesel exhaust induces changes in EEG in human volunteers. Particle and Fibre Toxicology. Particle and Fibre Toxicology 2008, 5:4.
3. Franco Suglia et al. Association of black carbon with cognition among children in a prospective birth cohort study. American Journal of Epidemiology 2008 167(3):280-286.
Bisphenol A contamination in plastic bottles
Plastic water bottles were taken off the shelves in Canada last month and caused concerns worldwide. The offending substance in the bottles is bisphenol A (BPA), an endocrine-disrupting chemical (EDC). In the latest issue of Toxicology Letters, American researchers published the results of their research on the health risks of BPA [1].
BPA is “an estrogenic high-production chemical used primarily as a monomer for the production of polycarbonate and epoxy resins.” Bioactive BPA is released from polycarbonate bottles at rates ranging from 0.20ng/h to 0.79ng/h. There is no significant difference in the BPA migration rates in new and used bottles at room temperatures. At 100°C (e.g. contact with boiling water), the migration rates increased by up to 55-fold. The estrogenic bioactivity of the BPA-like immunoreactivity released into the water samples was confirmed using an in vitro assay of rapid estrogen signaling and neurotoxicity in developing cerebellar neurons.
Based on these findings, the following conclusions can made:
- Food and beverages which come in contact with epoxy resins or polycarbonate plastic containers may be contaminated by bioactive BPA.
- Human exposure to BPA is actually widespread and the substance should therefore be as a contributing source to the total “EDC-burden”.
This is not the first study to investigate the migration of PBA. However, there are differing opinions whether the amounts released are high enough to present a health risk. Aside from plastic bottles, other BPA sources are polycarbonate dental products and food packaging [2].
Sources:
1 Le HH, Carlson EM, Chua JP, Belcher SM., 2008. Bisphenol A is released from polycarbonate drinking bottles and mimics the neurotoxic actions of estrogen in developing cerebellar neurons. Toxicol Lett. 2008 Jan 30;176(2):149-56. Epub 2007 Nov 19.
2 Howdeshell KL, Peterman PH, Judy BM, Taylor JA, Orazio CE, Ruhlen RL, Vom Saal FS, Welshons WV., 2003. Bisphenol A is released from used polycarbonate animal cages into water at room temperature. Environ Health Perspect. 2003 Jul;111(9):1180-7.