Contaminants humans, effect

There has been considerable concern in recent years over the possible increasing trends for adverse effects on the reproductive capabilities of animals and man. In humans, effects such as decreased sperm count and increased testicular cancer in men and breast cancer in women are of particular concern.71 It has been proposed that a common cause for these diverse observations may be the disruption by certain environmental contaminants of the endocrine system which... 

Certain allegations of human health and environmental adverse effects are exempt from the requirements of the TSCA Section 8(c) rule including those that (1) are made anonymously (2) identify known human effects and (3) those that are directly attributable to an incident of environmental contamination that has already been reported to the US Government under any applicable authority. 

Recently. Liao et al. (1988) developed a relatively simple and rapid procedure for purifying human and bovine adipose tissue extracts so that trace levels of complex mixture of target analytes (including PAHs) could be detected and quantified by capillary GC/MS. By employing an activated Florisil column. Liao and co-workers showed that lipid contaminants bind effectively (more than 99.75%) with Florisil. thereby producing a relatively clean sample extract. A detection limit at a low ng/g level and an average sample recovery of 85% were achieved (Gay et al. 1980 Liao et al. 1988 Modica et al. 1982). 

Commercial liquid soap added with L-histidine was found to be more effective than the untreated soap. Similarly sodium-ethylene diamine tetraacetic acid (EDTA) salt or L-histidine added to phosphate buffer saline solution was more effective in cleaning nickel contaminated human skin than the phosphate saline alone. 

QCPs are intended to make available to analysts a standardized approach for minimizing analytical errors and to provide the assurance of the generation of good data with the best possible precision and accuracy. This is achieved by integrating into normal laboratory practices steps which would ensure freedom from somces of error such as contamination, matrix effects, human and instrumental bias and random errors, fluctuating instrumental sensitivity, and discrepancies in analytical standards. 

Discharges of contaminant lead have resulted in increases in organism and human lead levels comparable to increases documented in environmental matrices, as indicated by a recent estimate of the natural level of lead in blood of preindustrial humans (0.016 fxg/dL or 0.8 n. This estimate is 175-fold lower than average blood lead levels in the United States (2.8 /ig/ dL or 140 nl and 600-fold lower than the recently (1991) revised Centers for Disease Control (CDC) action level of concern for early toxic effects in children (10 fig/dh or 480 n. The significance of these comparisons to public health is corroborated by numerous studies suggesting that there may be no lower threshold for sublethal toxicity in contemporary (i.e., lead-contaminated) humans. Those data also indicate that environmental lead concentrations that were previously considered innocuous may be deleterious to human health. 

Polycyclic aromatic hydrocarbons are potent immunosuppressive environmental contaminants. Immunotoxic effects of PAHs, which may contribute to their carcinogenic potential, have been established in various animal models and in human immune cells (van Grevenynghe et al., 2004). Inhibition of the production of immunocompetent cells (lymphocytes and monocytes) is likely one of the mechanisms contributing to the immunosuppression due to PAHs. Exposure to PAHs inhibits the differentiation of monocytes into dendritic cells and macrophages it also induces apoptosis of both pre-T cells in the thymus and pre-B cells in the bone marrow, which may account for thymic atrophy and decreased lymphoid cell recovery from the spleen, lymph nodes, and bone marrow in PAH-exposed mice (Lutz et al., 1998 Page et al., 2002). These toxic effects towards precursors of immune cells have been linked, at least in part, to the PAHs metabolism into toxic reactive intermediates triggering apoptosis of pre-B eells (Mann et al., 1999). 

Repeated exposures of animals to high (near-lethal) concentrations of vapors result in inflammation of the respiratory tract, as weU as degenerative changes in the Hver, kidneys, and heart muscle. These effects arise at concentrations far above those causing irritation. Such effects have not been reported in humans. The low odor threshold and irritating properties of acrylates cause humans to leave a contaminated area rather than tolerate the irritation. 

Models for transport distinguish between the unsaturated zone and the saturated zone, that below the water table. There the underground water moves slowly through the sod or rock according to porosity and gradient, or the extent of fractures. A retardation effect slows the motion of contaminant by large factors in the case of heavy metals. For low level waste, a variety of dose calculations are made for direct and indirect human body uptake of water. Performance assessment methodology is described in Reference 22. 

Sanitization is a cleaning procedure that reduces microbial contaminants on certain surfaces to safe or relatively safe levels, as defined by the EPA or pubHc health authorities. The article is usually cleaned with hot water and various germicidal detergents. Sanitization can be safe for a product in contact with intact skin or for food utensils, but it is not considered safe for articles to be inserted in the human body. Effective sanitization is a requirement in the processing of reusable medical suppHes before packaging and sterilization. It is also a requirement in the maintenance of utensils and containers used for food preparation. 

Human Health Effects. Any assessment of adverse human health effects from PCBs should consider the route(s) of and duration of exposure the composition of the commercial PCB products, ie, degree of chlorination and the levels of potentially toxic PCDF contaminants. As a result of these variables, it would not be surprising to observe significant differences in the effects of PCBs on different groups of occupationally-exposed workers. 

Environmental exposures to PCBs are significantly lower than those reported in the workplace and are therefore unlikely to cause adverse human health effects in adults. However, it is apparent from the results of several recent studies on children that there was a correlation between in utero exposure to PCBs, eg, cord blood levels, and developmental deficits (65—68) including reduced bkth weight, neonatal behavior anomaUes, and poorer recognition memories. At four years of age, there was stiU a correlation between prenatal PCB exposure levels and short-term memory function (verbal and quantitative). In these studies the children were all exposed to relatively low environmental levels of PCBs. Although these effects may be related to other contaminants, it is clear that this is an area of concern regarding the potential adverse human health impacts of PCBs. 

Control of metalloid content in natural objects, foodstuff and pharmaceuticals is an important task for modern analytical chemistry. Determination of elements such as Arsenic is necessary for evaluation of object toxicity, since their content in environment may exceed MCL (maximum contaminant level), posing hazard to human health. Elements such as Selenium in definite doses are healthy, but in greater quantities they produce toxic effect. 

It is known that the brain is one of the most sensitive sites of action of steroids in utero, and recently there have been suggestions that EDs may affect normal brain development and behaviour. For example, it has been alleged that in utero exposure to polychlorinated biphenyl compounds (PCBs) resulted in adverse effects on neurologic and intellectual function (memory and attention) in young children born to women who had eaten PCB contaminated fish in the USA." It has also been speculated that exposure to environmental pollutants with steroidal activity may be infinencing human sexual development and sexually controlled behavioiir." ... 

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