Benchmark values

Person R C, McKenna D R, Ellebracht J W, Griffin D B, McKeith F K, Scanga J A, Beltk K E, Smith G C and Saveli J W (2005), Benchmarking value in pork supply chain processing and consumer characteristics of hams manufactured from different quality of raw materials , Meat Sci, 70, 91-97. 

With the aim to obtain additional benchmark values, a larger number of substituted phenyllithium complexes with known solid state structures were included in this study . They range from monomers of different solvation, over dimers and one trimer to different tetramers. The investigated aryl systems are shown in Scheme 2 and the obtained x values are reported in Table 7. 

Calcnlation of the interest rates at which NPV=0 can be tedious. Computer software exists to do this job, but quite accurate estimates can be obtained simply by calculating some benchmark values, plotting a graph of interest rate vs. NPV and then interpolating to obtain the reqnired value of /. 

A recent study combined quantum chemical calculations and electron diffrac-tion/photoelectron spectroscopy to derive the following dialkylzinc gas phase enthalpies of formation ethyl, 57 8 n-propyl, 10 8 isopropyl, 32 8 f-butyl, —17 8 neopentyl, — 117 8 kJmoF. The benchmark value of 53 1 kJmol was chosen for the gas phase enthalpy of formation of dimethylzinc. Compared to the experimental values, the diethyl and dineopentyl values are very close, but the w-propyl enthalpy of formation is just barely within the combined large error bars. The methylene increment from the theoretically derived values of diethylzinc and di-n-propylzinc is —23.5 kJ mol , a value that is consistent with other gas phase homologous series. Using this increment, the enthalpies of formation of gaseous di-w-butylzinc and di-n-pentylzinc are calculated to be —37 and —84 kJmoU, respectively. 

Various sediment quality guidelines (SQGs) and benchmark values have been proposed by several states and federal agencies in the USA and other countries. However, none of these benchmarks have been adopted for widespread regulatory applications. Concentrations of TEQ in... 

The reference concentration (RfC) methodology to estimate benchmark values for noncancer toxicity of inhaled chemicals was adapted for inhalation studies from the reference dose methodology used for oral exposure assessment. The same general principles were used, but the RfC methodology was expanded to account for the dynamics of the respiratory system as a portal of entry. The reference dose (RfD) methodology included dosimetric adjustments to account for species-specific relationships of exposure concentrations to deposited or delivered doses. Particles and gases are treated separately, and the type of toxicity observed influences the dosimetric adjustment applied to score the exposure concentration for animals to a human equivalent concentration. 

The TEC may be a test end-point, a test end-point corrected by a factor or other extrapolation model or a regulatory criterion or other benchmark value. A hazard quotient (HQ) greater than unity is treated as evidence that the chemical is worthy of concern. Suter (1996) also suggests that, if numerous chemicals occur at potentially toxic concentrations, an index of total toxicity could be calculated by the sum of toxic units (XTUs). This permits a comparison of COPECs and examines their distribution across areas within a site. The TUs are quotients of the concentration of a chemical in a medium divided by the standard test end-point concentration for that chemical. 

Instead of doing more or less doubtful extrapolations down to responses of 10 or 10 so-called benchmark values are sometimes determined. A dose-response regression line for the most appropriate endpoint is made. The dose producing 10% response and its 95% confidence interval are determined. The lower confidence limit is defined as the benchmark value (see Figure 10.2). This dose is then used to define a dose regarded as safe, by dividing it with an unsafety factor. 

EM Species Soil Type Soil pH OM (%) Clay (%) Toxicity Benchmark Value (mg kg-1) Exposure ERE Ref. 

The ecotoxicological data selected for developing soil invertebrate-based ETVs that can be proposed as screening concentrations for RDX, HMX, CL-20, TNT, 2,4-DNT, 2,6-DNT, and TNB are summarized in Table 12.3. These toxicity benchmark values were established in definitive tests with the soil invertebrates earthworm Eisenia fetida [33], potworm Enchytraeus crypticus [34], and collembola Folsomia Candida [35], These species are representative surrogates of species that normally inhabit a wide range of site soils and geographical areas. Reproduction measurement endpoints in these tests were more sensitive compared with adult survival [24-28,31] and were consequently used for derivation of proposed soil invertebrate-based ETVs. These endpoints included cocoon production and juvenile production for earthworms, and juvenile production for potworms and collembola. 

Table 1 Soil ecotoxicological benchmark values taken from various sources (taken from ref. 4)...

States in the northeast have varying types of benchmarks for allowable concentrations of MTBE in drinking water. Table 1 lists benchmarks for MTBE in drinking water in each of 12 Northeastern states. The benchmark values listed in Table 1 represent a variety of enforceable and unenforceable guidehnes for MTBE in drinking water. Some states have primary drinking-... 

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