Type a term:
Air and Dust SamplesMany of our daily activities result in the production of chemicals that are released into the air that we breathe in our homes and in our communities. These include exhaust from cars, trucks and buses; chemical used as cleaning agents and other household products; and by-products of manufacturing any of the hundreds of plastic and electrical conveniences that make up so much of our personal and social worlds. Other residues from air cling to dust or other particles that we may breathe or have physical contact with, even though we may not be aware this is happening.
What are the chemicals that are causing concern and where are they found?
Endocrine disrupting compounds including phthalates, parabens, alkylphenols, and pesticides are used in consumer products such as plastics, detergents, cosmetics, furniture, and pest control chemicals. They have been found in air and dust samples from residential homes.
Polycyclic aromatic hydrocarbons (PAHs) are formed from the burning of organic materials. These chemicals are environmental pollutants found in exhaust, cigarette smoke and in ‘char’ on grilled foods. PAHs are not only found in air and dust, but also in soil, water, and stream sediment.
Polybrominated diphenyl ethers (PBDEs) are commercially produced substances that are used as flame-retardants in a wide variety of consumer products. PBDEs are added to polyurethane foam and various plastics, and therefore may be found in furniture stuffing, carpet backings, non-clothing textiles, electrical insulation, computers and televisions. These chemicals are persistent in the environment and have been detected in indoor air, outdoor air, household dust, and food. PBDEs are also present in human breast milk, blood, and fat tissue.
How do these chemicals enter the body?
Exposure to chemicals found in air and dust occurs by breathing in polluted air and through skin contact in the case of dust.
For PAHs specifically, exposure results from breathing in contaminated air in occupational settings, and from tobacco smoke, wood smoke, traffic exhaust, and other contaminated air; from eating charbroiled foods, and from drinking contaminated water [Baird et al., 2005].
The main sources of exposure to PBDEs appear to be through food, human breast milk, and dust. Exposure also results from use of consumer products that contain these chemicals, including upholstered furniture and padded mattresses, when they escape into the air, dust, and food supply. When they are eaten, inhaled, or absorbed through the skin, PBDEs circulate throughout the body and may exhibit a bio-accumulative effect. Thus the chemicals remain in the body and build up over time in fatty tissue [Rahman et al., 2001].
What are the mechanisms by which these substances might increase the risk for breast cancer?
PAHs have been shown to induce DNA damage and disrupt cell cycle progression. This is seen in the presence of PAH-DNA adducts, a measure of DNA damage from exposure. PAHs have also been implicated in the disruption of DNA repair processes, specifically impairing genes that mediate DNA repair, making the correction of damage done to DNA more difficult and less likely [Jeffy et al., 2002].
PBDEs have been shown to exhibit estrogenic properties, acting as agonists for estrogen receptors. This suggests that these chemicals have the ability to mimic the action of and induce the same responses as natural estrogens in the cell. Once in the body, PBDEs may also break down into more potent estrogen-mimicking metabolites. Some of the most commonly reported PBDE varieties found in humans and other mammals (especially BDE-100) have been shown to possess the highest estrogenic activity when compared to other formulations of these chemicals [Meerts et al. 2001].