Health reducing exposure

Potential health and safety problems of acryflc polymers occur in their manufacture (159). During manufacture, considerable care is exercised to reduce the potential for violent polymerizations and to reduce exposure to flammable and potentially toxic monomers and solvents. Recent environmental legislation governing air quality has resulted in completely closed ketde processes for most acryflc polymerizations. Acryflc solution polymers are treated as flammable mixtures. Dispersion polymers are nonflammable. 

Handling, Health, and Safety of Methacrylic Monomers. Good ventilation to reduce exposure to vapors, splashproof goggles to avoid eye contact, and protective clothing to avoid skin contact are required for the safe handling of methacrylic monomers. A more extensive discussion of safety factors should be consulted before handling these monomers (28). 

Personal protective equipment (PPE) Devices and apparel worn by employees to prevent or reduce exposure to health and safety hazards in any adverse environment. Examples include respirators, gloves, chemical-resistant overalls, earplugs, and safety glasses. 

Mild skin irritation has been reported by workers at a munitions factory who were exposed to low levels of hexachloroethane. The workers were wearing protective clothing that greatly reduced exposure. No other information is available concerning health effects in people exposed to hexachloroethane. However, results of animal studies can be used to show how it can affect your health. Based on the animal data, hexachloroethane in the air can irritate your nose and lungs and cause some buildup of mucus in your nose, much like an allergy. It can also irritate your eyes and make them... 

Inability in most instances to detect potential beneficial health effects from reduced exposure to chemicals due to the chronic nature and multifactorial etiologies of the conditions in question. 

The lack of information is well illustrated by trying to examine the costs and benefits of TSCA. The major benefits of the act are the adverse health effects avoided by whatever actions are taken under the act s authority or because of the act s existence. But for many actions, such as voluntary testing by industry, we are not sure whether to attribute the action to TSCA s existence. We also are not sure how to relate such actions to reduced exposure to potentially hazardous chemicals. Insofar as exposure is reduced, we usually do not have any precise idea of the health consequences of such reduced exposure. And even if we knew the health consequences we would not know how to place a dollar value on them. 

The substances we have described in this book turn out to be, for the most part, minor threats to our health. There are, however, perhaps thousands of these threats, and so a regulatory system has evolved to reduce the risks of individual substances to very low levels. There is considerable work yet to be done, to learn the toxic properties of many poorly tested chemicals, and to assess their health risks, but once this is done, regulatory officials have available strong weapons (which they do not always choose to deploy) to reduce exposures when necessary. The burden for exposure reduction falls not on exposed individuals (as in the case of lifestyle factors), but rather upon those who have caused the exposures to occur. 

DNB and 1,3,5-TNB are suspected to cause similar health effects. Exposure to high concentrations of 1,3-DNB can reduce the ability of blood to carry oxygen and can cause your skin to become bluish in color. If you are exposed to 1,3-DNB for a long time, you can develop a reduction (or loss) in the number of red blood cells (anemia). Other symptoms of 1,3-DNB exposure include headache, nausea, and dizziness. We do not know if there are any long-term health effects of exposure to 1,3-DNB or 1,3,5-TNB in people. We also do not know if 1,3-DNB or 1,3,5-TNB causes birth defects or cancer in people. 

Exposure is also affected by absorption. Even though we may come into contact with an agent, if little is taken up into the body (or absorbed), there is little effect. For example, the metallic mercury from a broken thermometer, if swallowed, is very poorly absorbed by the gut and will be excreted in the feces. However, if this same amount of mercury were allowed to evaporate and be inhaled, there would be very serious health consequences. This example shows that metabolism and excretion modify absorption. What is not absorbed (and even some of what is absorbed) may be excreted from the body by various routes, including the urine, feces, and sweat or through exhalation. Excretion reduces the effect because it lowers the amount of toxicant in the body, thus reducing exposure to sensitive organs. 

No matter how much is learned about chemical exposures or what measures individuals and governments take to manage them, some exposure risks will remain. For as the risk approaches zero, the cost of reducing exposures rises rapidly and exceeds any resulting health benefits. 

The first National Report on Human Exposure to Environmental Chemicals was initially released in 2001 and is based on analyses of NHANES biomonitoring data on exposure to chemicals. The data have various uses to determine which chemicals people are exposed to and at what concentrations to establish reference ranges for assessing whether an individual or group has an unusually high exposure, including susceptible populations, such as children, the elderly, and women of childbearing age to track exposure trends to assess the effectiveness of public-health efforts to reduce exposure of Americans to specific chemicals and to set priorities for research on human health effects (CDC 2005). 

HBM values are derived from toxicologic and human studies and are health based (Jakubowski and Trzcinka-Ochocka 2005). Two types of HBM values exist HBM I, the concentration of an environmental toxin in human biological material below which there is no risk of adverse health effects and HBM II, the concentration above which there is an increased risk of adverse health effects in susceptible individuals in the general population (Jakubowski and Trzcinka-Ochocka 2005). An HBM I value serves as an alert level, and an HBM II value is an action level at which immediate efforts should be made to reduce exposure and further clinical examination should follow (Ewers et al. 1999). HBM values and reference values have been derived for a number of chemicals, including lead, cadmium, mercury, pentachlorophenol (PCP), and arsenic. 

Linkage Physical merging of health and exposure data sets to explore research questions and conduct ecological analyses Can be completed in a relatively short period of time, often at reduced research cost Completeness of case ascertainment varies by type (active versus passive) of surveillance... 

The large-scale monitoring studies enable researchers to track, over established time periods, trends in levels of exposure in human populations and to assess the effectiveness of public health efforts to reduce exposure to specific harmful chemicals. Aylward and Hays (2002) summarized recent trends in dioxins intake in the United States and in Western Europe. The intake estimates show clear decreases of... 

The Department of Health is reported to be searching for diethylhexyl phthalate-free products for the National Health Service following international concern over possible health effects from exposure to the plasticiser. The EU Scientific Committee on Medicinal Products Medical Devices has made no recommendation that hospitals should take any precautionary measures to reduce exposures of groups of patients considered to be at risk although Health Canada and the FDA have issued precautionary assessments. 

REACH introduces the concept of adequate control in EU chemical law. Traditionally, the term adequate control has been used to refer to good practice in the workplace. REACH now redefines adequate control in the form of risk management measures detailed in an exposure scenario necessary for the control of hazardous properties. Through a set of systematic procedures, risk management measures must be selected to reduce exposure below which adverse effects to human health or the environment are likely to occur (i.e., a DNEL, DMEL or PNEC). There is debate as to whether a concept of a safe level of exposure reduction, similar to adequate control, can apply to non-threshold carcinogens and mutagens, endocrine disruptors, persistent, bioaccumulative and toxic (PBT) or VPVB substances (e.g., [270]). Industry may need to demonstrate that exposure to these substances is always avoided or minimised, as specified in Annex I of the REACH Regulation. 

---