Environmental relevance

TnJluoromethjl)aniline, P> JA. Substance Keport44 (Sept. 1989), Advisory Board for Environmental Relevant Waste of the German Chemical Society, VCH Pubhshers, Weinheim, Germany, 1990, 58 pp. 

The acute toxicity of chlorinated paraffins to mammals, binds, and fish is very low (8), but over longer periods of exposure certain chlorinated paraffins have proved to be toxic to some aquatic species. However, the very low water solubility of chlorinated paraffins has made studies on aquatic species complicated. Laboratory experiments in which the chlorinated paraffins had been artificially solubilized showed only the short-chain grades to be toxic at low concentration other longer-chain grades showed no adverse effects on the majority of aquatic species tested. The degree of solubilization achieved in the laboratory is unlikely ever to be experienced in the environment and is of doubtful environmental relevance (9). 

DYNAMIC LEACHING OF ENVIRONMENTALLY RELEVANT FORMS OF HEAVY METALS FROM SOILS... 

Accumulation of heavy metals (HM) in different compartments of the biosphere, and their possible mobilization under changing environmental conditions induce a perturbation of the ecosystem and adverse health effects. Fast and correct estimating the environmentally relevant fonus of HM in soils, sediments, and sewage sludge is an urgent need for environmental monitoring and assessment. 

Edgren carried out a number of studies in which bioassays were used to compare the widely differing potencies of a number of analogues of 17/i-oestradiol that were modified in the 18-position. Commenting on the use of potency ratios, Edgren concluded that they were only valid for specific substances and test systems and useless for product safety testing . These problems could have important consequences for any attempt to establish the potency of specific environmental EDs or environmentally relevant mixtures. 

Compounds Affecting Rq>roduction Compounds that can affect reproductive function include several drugs and occupationally important chemicals such as solvents and pesticides as well as a number of environmentally relevant com-fxrunds. A group of chemical compounds that has received much attention recently is endocrine disrupters, many of which are halogenated hydrocarbons, e.g., PCBs. These are known to induce feminization in fish and other animal species.1.5/ There is intense debate about the significance of these compounds to human health. Tobacco smoke and ethyl alcohol also have major effects on human reproduction, the effects of alcohol being especially important. Table 5.17 lists compounds that may disturb the functions of female and male reproductive functions. 

The higher molecular weight organotin(IV)s, such as TBT and TFT, are known to be immunotoxic and to cause renal and hepatic damage. TBT at environmentally relevant concentrations increases intracellular concentration of Ca(II) ([Ca(II)],) in murine thymocytes by increasing membrane Ca(II) permeability and... 

High school students should have a greater understanding of global environmental issues. This can be accomplished by using environmentally-relevant examples to teach high school chemistry. Appropriate demonstrations and laboratory experiments that illustrate these topics are suggested. To incorporate additional environmental chemistry in die secondary curriculum, help from environmental scientists will be needed. 

Studies of the effects of in vitro exposure to a range of concentrations (encompassing environmentally relevant concentrations of monobutyltin, dibutyltin, and tributyltin) on human natural killer lymphocytes obtained from adult male and female donors revealed the presence of detectable concentrations of the butyltins in all the donors, indicating possible exposure of natural killer cells to butyltins in the blood. It was suggested that the study provided evidence that butyltin compounds significantly inhibit natural killer cell function and possible natural killer cell-mediated potential in humans (Whalen etal, 1999). 

Whalen MM, Loganathan BG, Kannan K(1999) Immunotoxicity of environmentally relevant concentrations of butyltins on human natural killer cells in vitro. Environmental Research, 81(2) 108-116. 

The mink Mustela vision) is a piscivorous mammal that also has been exposed to relatively high dietary levels of methyl mercury in North America in recent times. In a Canadian study, mink trapped in Yukon territory, Ontario, and Nova Scotia were analyzed for levels of mercury and abundance of muscarinic, cholinergic and dopaminergic receptors in the brain (Basu et al. 2005). A correlation was found between total Hg levels and abundance of muscarinic receptors, but a negative correlation was found between total Hg and abundance of dopaminergic receptors. Thus, it was suggested that environmentally relevant concentrations of Hg (much of it in methyl form) may alter neurochemical function. The highest levels of mercury contamination were found in mink from Nova Scotia that had a mean concentration of total Hg of 5.7 pg/g in brain, 90% of which was methyl mercury. 

More controversially, endocrine disruption as a consequence of exposure to the herbicide atrazine (2-chloro-4-ethylamine-6-isopropylamine-s-triazine), one of the most widely used herbicides in the world, has also been hypothesized to explain various adverse biological effects in frog populations in the United States. Exposure to atrazine in the laboratory at high concentrations, far exceeding those found in the natural environment, has been reported to induce external deformities in the anuran species Rana pipiens, Rana sylvatica, and Bufo americanus (Allran and Karasov 2001). Studies by Hayes et al. have suggested that atrazine can induce hermaphroditism in amphibians at environmentally relevant concentrations (Hayes et al. 2002 Hayes et al. 2003). Laboratory studies with atrazine also indicated the herbicide... 

The effects of EDCs on behavior in fish have been more extensively studied than in birds. Examples of the effects of EDCs seen in fish include profound alterations in courtship behavior in male guppies (Poecilia reticulate) exposed to vinclozolin and DDE, including at environmentally relevant concentrations (Baatrup and Junge 2001) and altered courtship behavior in three-spined stickleback exposed to environmentally relevant concentrations of EE2 (Bell 2001). In the stickleback studies, exposed males became less aggressive and had a reduced nesting activity, and this was linked with reduced concentrations of the male sex androgen 11-ketotestosterone. Recently,... 

Consistent with the preceding comments on the metabolism of xenobiotics in the presence of additional carbon substrates, the result of deliberate addition of organic carbon may be quite complex and will not be addressed in detail. Two examples on rates of mineralization are given as illustration in which addition of glucose apparently elicited two different responses. It should, however, be emphasized that since the concentration of readily degradable substrates in natural aquatic systems will generally be extremely low, the environmental relevance of such observations will inevitably be restricted ... 

An appropriate mineral medium supplemented with the organic compound that is to be studied is inoculated with a sample of water, soil, or sediment. In studies of the environmental fate of a xenobiotic in a specific ecosystem, samples are generally taken from the area putatively contaminated with the given compound so that a degree of environmental relevance is automatically incorporated. Attention has, in addition been directed to pristine environments, and the issues of adaptation or preexposure have already been discussed. 

Laboratory experiments using natural consortia under defined conditions have particular value from several points of view. They are of direct environmental relevance, and their use minimizes the ambiguities in extrapolation from the results of studies with pure cultures. They provide valuable verification of the results of studies with pure cultures and make it possible to evaluate the extent to which the results of such studies may justifiably be extended to the natural environment. It should be appreciated, however, that in some cases the habitats from which the inoculum was taken might already have been exposed to xenobiotics so that natural enrichment (preexposure) could already have taken place. This has been discussed in Chapter 4. 

It is desirable to determine the chemical properties of irrigation water, paddy water in the field, and adjacent streams and rivers. Since especially the pH of the paddy water fluctuates diurnally (high in daytime and low at night), this may affect the water solubility of certain chemicals, e.g., sulfonylureas, which have dissociation constants (p/fa) in an environmentally relevant range. 

Neonicotinoids are generally polar, nonvolatile crystals with high water solubility. They are nonionized at environmentally relevant pH and are stable to heat and sunlight. Neonicotinoids are stable to acid hydrolysis. Except for thiacloprid, they are susceptible to alkaline hydrolysis. 

Foster WG, McMahon A, Rice DC. 1996. Sperm chromatin structure is altered in cynomolgus monkeys with environmentally relevant blood lead levels. Toxicol Ind Health 12(5) 723-735. 

Such relationships have been applied to solubility, vapor pressure, Kow, KAW, KOA, Henry s law constant, reactivities, bioconcentration data and several other environmentally relevant partition coefficients. Of particular value are relationships involving various manifestations of toxicity, but these are beyond the scope of this handbook. These relationships are valuable because they permit values to be checked for reasonableness and (with some caution) interpolation is possible to estimate undetermined values. They may be used (with extreme caution ) for extrapolation. 

Shiu, W.-Y., Ma, K.-C., Varhanickova, D., Mackay, D. (1994) Chlorophenols and alkylphenols A review and correlation of environmentally relevant properties and fate in an evaluative environment. Chemosphere 29(6), 1155-1224. 

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