Index for toxicity

THE SED-TOX INDEX FOR TOXICITY ASSESSMENT OF CONTAMINATED SOLID MATRICES... 

As an index for toxicity of gaseous substances, the median lethal concentration (LC 5 0 ) and the threshold limit value (TLV) are used to evaluate acute toxicity. LCso is the gas concentration (ppm) in air which results in the death of 50% of a population of test animals by inhalation. TLV is the threshold limit of exposure which does not cause any serious sickness in workers under normal conditions of an 8 hours day and a 40-48 hour work week. TLV is usually given in combination with the time-weighted-average concentrations for 8 hours per day (TLV—TWA), or with the short time exposure limit (TLV-STEL), which is that exposure which should not be exceeded even for a relatively short period (15-30 minutes), or with the ultimate limit (TLV-C), which defines the exposure level that should not be exceeded under any circumstances. 

Risk Characterization. Once a quantitative exposure assessment has been made, Risk Assistant allows the user to automatically calculate lifetime excess cancer risk and/or a hazard index for toxic non-carcinogenic effects of chronic exposure for any agent included in the toxicity databases which currently include about 300 compounds. The appropriate hazard values (slope-potency factors and reference doses) for the relevant routes of exposure are automatically retrieved from the databases. The uncertainty calculations in the exposure assessment can also be retrieved to assess the range of risks associated with a given exposure situation. 

As is needed for all potential risks for chemical substances, an index of toxicity enables quantification of risk. Nevertheless, it only applies to risk by inhalation, which is yet the most common as well as insidious risk under normal working conditions with chemical substances. However, this approach should be treated with caution because of the difficulties inherent in toxicological risks. At this stage of the analysis it is essential to work in collaboration with the company doctor, whose total agreement is necessary. 

TLVs should not be used for (1) a relative index of toxicity, (2) air pollution work, or (3) assessment of toxic hazard from continuous, uninterrupted exposure. 

Table 1 shows the ratios of LD50 values of various insecticidal components for mammals and insects, i.e., indexes for selective toxicity. 

In this thesis an inherent safety index for evaluating inherent safety in preliminary process design was presented. The inherent safety of a process is affected by both chemical and process engineering aspects. These have been dealt separately, since the index was divided into the Chemical Inherent Safety Index and the Process Inherent Safety Index. These two indices consist of several subindices which further depict specific safety aspects. The Chemical Inherent Safety Index describes the inherent safety of chemicals in the process. The affecting factors are the heat of the main reaction and the maximum heat of possible side reactions, flammability, explosiveness, toxicity, corrosiveness and the interaction of substances present in the process. The Process Inherent Safety Index expresses safety of the process itself. The subindices describe maximum inventory, maximum process temperature and pressure, safety of equipment and the safety of process structure. 

Lithium is commonly used for bipolar affective disorders. Lithium however has a narrow therapeutic index and high risk for toxicity (Groleau 1994). The use of loop diuretics or ACE-inhibitors significantly increases the risk of hospitalisation for lithium toxicity in the elderly (Juurlink et al. 2004). Treatment of elderly patients with lithium should be thoroughly monitored. 

Buetzer P. 1985. [Handling of toxic substances Experience and hazard A vapor hazard index for substances.] Swiss Chem7(9) 25-26, 28. (German)... 

Extrapolations of therapeutic index and toxicity data from animals to humans are reasonably predictive for many but not for all toxicities. Seeking an improved process, a Predictive Safety Testing Consortium of five of America s largest pharmaceutical companies with an advisory role by the Food and Drug Administration (FDA) has been formed to share internally developed laboratory methods to predict the safety of new treatments before they are tested in humans. In 2007, this group presented to the FDA a set of biomarkers for early kidney damage. 

The higher the therapeutic index, the safer the drug the lower the therapeutic index, the greater the possibility of toxicity. The therapeutic index for barbiturate as a class is 10, whereas the therapeutic index for cardiac glycoside as a class is 3. Because the usual therapeutic dose of cardiac glycoside is 1 mg, death may result if only 3 mg has been administered. 

SMITH, C.F., COHEN, J.J. and MCKONE, T.E. (1980). A Hazard Index for Underground Toxic Material, Lawrence Livermore National Laboratory Report UCRL-52889 (National Technical Information Service, Spring-field, Virginia). 

An index of toxicity is intended to be a simple tool that allows integrating and summarizing several variables into a single value. Realistically, this cannot be inferred without a judgement by environmental protection experts who consider all parameters available for their classification. PLS regression helped calculate an index fitted to expert judgement. The loss of information owing to the transformation of a multivariate situation to a univariate one was thus minimized since it is an inherent characteristic of multivariate analytical tools. 

Results of the EDAR index application to these types of matrices are provided in Table 5. Samples were selected for toxicity screening to ensure the presence of different types of contaminants commonly present in complex wastes (e.g., hydrocarbons, DOC, nutrients, ammonia, inorganic anions and cations, pesticides) and other matrices (e.g., sediments and sludges, solid materials, liquid... 

The battery of test approach for toxicity testing is now a universally-accepted concept. It has recently been applied in Latin American countries and is presently recognized as a critical tool for the assessment of complex mixtures. Interpretation of hazard by reducing complex ecotoxicological data into a single numerical value (e.g., PEEP index) is generally favoured by decision-makers involved in various facets of environmental regulation. 

The purpose of this paper is to describe the SED-TOX index for the toxicity assessment of contaminated solid matrices, particularly sediments, demonstrate its discriminative potential, and show its correlation with chemical analyses derived data and indices of benthic community structure. 

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