Toxicological impact

Abstract The characterization of toxicological impact of chemicals and mixtures from environmental matrices is a critical point in the assessment of adverse effects induced in human and ecological targets. In fact, the toxicity of most of the environmental mixtures is still under investigation due to the possibility of synergic or antagonistic effects of the components. Moreover, in some cases, the toxicity of identified chemicals is not already well known and it could be an additional matter of concern. 

Sladek NE. Human aldehyde dehydrogenases potential pathological, pharmacological, and toxicological impact. J Biochem Mol Toxicol 2003 17(l) 7-23. 

Possible applications and types of bioassays needed to determine toxicological impact from dredged sediment... 

This nonextractable radioactivity was probably the result of covalent binding of the furazolidone intermediates to endogenous macromolecules. The bioavailability of these bound tissue residues from the above pig residue depletion study was determined by feeding rats lyophilized samples of liver and muscle tissues from animals sacrificed at 0 and 45 days after the last treatment (132). Results showed that the fraction of the bound residues bioavailable to rats was in the range 16-41%. The toxicological impact of these bioavailable bound residues has not been yet determined. 

In this way the amounts of the different PCDDs, PCDFs and PCBs can now be converted to one figure which is a measure of the toxicological impact of the detected mixture. This approach simplifies the reporting of surveys for PCDDs, PCDFs and PCBs in food, allowing the correlation of different surveys from country to country and a greater understanding of dietary exposure. 

Tanabe, S., Iwata, H., Tatsukawa, R., 1994. Global contamination by persistent organochlorines and their eco-toxicological impact on marine mammals. Sci. Total Environ. 15, 163-177. 

Landis, W.G. and Yu, M.-H., Introduction to Environmental Toxicology Impacts of Chemicals upon Ecological Systems, Lewis Publishers/CRC Press, Boca Raton, FL, 1998. 

MacGregor JT (2003) The future of regulatory toxicology Impact of the biotechnology revolution. Toxicological Sciences 75 236-248. 

Yu M-H (2002) Environmental Toxicology Impacts of Environmental Toxicants on Living Systems. Boca Raton, FL Lewis Publishers. 

It is important to additionally account for differences in potential toxicological consequences (severity, damage, or impact) in the comparison. Characterization factors can be expressed in terms of metrics such as DALYs (disability adjusted life years) for human health, for example. The results for toxicological impacts can be directly cross-compared with those of DALY-based indicators for other impact categories, such as for climate change. 

An LCA study can include the consideration of contributions to potential regional and global scale toxicological impacts. These contributions are calculated using characterization factors. Characterization factors linearly express the cumulative contribution to the risk of a potential toxicological impact and the relative consequences that are attributable to releasing a unit mass (e.g., 1 kg) of a chemical into the environment. 

An implicit assumption of the MFC is that the acclimation time is sufficient for coevolution to occur and that coevolution is important to assess the impacts of xenobiotics upon communities. The use of a "natural" inocula should increase species diversity and complexity over a protocol such as the SAM, but the smaller size of the test vessel would tend to decrease species number. Debate also exists as to the applicability of coevolution in the evaluation of test chemicals. If algal populations and others are primarily regulated by density-independent factors, then population-specific interspecific interactions may not be particularly important. If ecosystems are loosely connected in an ecological sense, coevolved assemblages may be rare. On the other hand, in enclosed systems that are islands, these relationships may have had an opportunity to occur, and coevolved interactions may be important in the assessment of toxicological impacts. 

Introduction to environmental toxicology impacts of chemicals upon ecological systems / Wayne G. Landis, Ming-Ho Yu.—3rd ed. p. cm. 

Dr. Yu serves as an associate editor of Fluoride, the official journal of ISFR. He is a founding co-editor of Environmental Sciences, a journal published by MYU K.K. in Tokyo, Japan. He co-edited Environmental Fluoride 1985, published by Elsevier Science in 1986. He is the author of Environmental Toxicology — Impacts of Environmental Toxicants on Living Systems, published by CRC Press. 

Air pollution results in the uptake of large numbers of chemicals of widely differing chemical and toxicological properties. When mixtures are inhaled (as is the case almost constantly) toxicological impacts that are not predicted from the known properties of the individual polluntants may ensue. This is particularly so when at least one of the chemicals is lipophilic and one is hydrophilic. 

The toxicological impact of polluted soil on humans is indirect. Chemical pollutants in soil affect the ability of soil to support plant life (fertility) by depressing microorganistic and soil-dwelling animal activities. Plants growing in polluted soil absorb toxic chemicals through their root systems and induce toxic effects in humans when those plants are ingested. Polluted soil also adversely affects humans via bioaccumulation of toxic chemicals in animals when plants that have absorbed these chemicals from polluted soil are eaten or when they are dermally absorbed by animals that come in contact with such soil. 

Riley, R. The potential pharmacological and toxicological impact of P450 screening. Curr. Opin. Dmg Discov. Dev. 2001,4, 45-54. 

Farmer, P. B. (2004b). Exposure biomarkers for the study of toxicological impact on carcinogenic processes. lARC Sci Publ, 71—90. 

IDLH Immediately Dangerous to Life or Health levels indicate that exposure to the listed concentrations of airborne contaminants is likely to cause death, immediate or delayed permanent adverse health effects, or prevent escape from the contaminated environment. IDLH levels are established to ensure that the worker can escape from the contaminated environment in the event of a failure of respiratory protection. An indication of "10% LEL" indicates that, for safety considerations, the IDLH was based on an atmospheric concentration of ten percent of the lower explosive limit even though toxicological impacts might not appear until higher concentrations are reached. 

Larsen HF, Birkved M, Hauschild M, Pennington MW and Guinee JB (2004) Evaluation of Selection Methods for Toxicological Impacts in LCA - Recommendations for OMNIITOX. Int J LCA 9 307-319 Le Teno, JF (1999) Visual Data Analysis and Decision Support Methods for Non-Deterministic LCA. Int J LCA 4 41-47... 

FIGURE 3.1 Schematic toxicological impacts of TNT on the soil microbial community. 

Reduction of the nitro groups of TNT has pronounced toxicological impact because the amino reduction products of TNT differ in toxicity and bioavailability from the parent compound (see examples in Chapter 3). It is important to note that apart from electrochemical reduction, TNT is largely nonreactive. However, conversion of the nitro groups of TNT to less oxidized species in the body or in the environment yields much more reactive compounds. This reactivity is important from the standpoint of bioaccumulation. These reduction products do not differ greatly from the parent compounds in Kow and are therefore insufficiently hydrophobic to bioaccumulate in lipids. However, they differ from their parent compounds in their ability to generate covalent bonds with biological macromolecules and this activity provides alternate routes for bioaccumulation. 

Gulson etal., 1995 Kim etal., 1998 Rasmussen etal., 2001). The precise causes for elemental enrichment in household dust are in most cases unknown, and there is little evidence as to the toxicological impact (with the exception of Pb), but the widespread nature of the observation points to the importance of understanding indoor accumulation processes and indoor sources. 

The quality and quantity of the respective element species in a matrix, rather than total element concentration, is highly responsible for the mobility, bioavailability and finally the ecotoxicological or toxicological impact of the element (Templeton et al. 2000). Therefore, only detailed knowledge about the species gives a basis for an assessment whether the element is toxic, without... 

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