Tolerable Daily Intakes

The average limit of a tolerable daily intake was fixed by the World Health Organization (WHO) as 0.5 p-gkg-1 day-1 for triphenyltin and this figure corresponds to an allowed concentration in fish of 0.25 Xgg-1. About half the triphenyltin concentrations shown in Figure 6 are higher than the limit of 0.25 pgg-1. The decline of these triphenyltin concentrations is expected since the banning. 

Penninks108 assessed the evaluation of a safety factor to determine a Tolerable Daily Intake (TDI) value for the environmental contaminant bis(tributyltin)oxide (TBTO). The... 

ADI is also used by WHO/FAO and many other countries for substances intentionally introduced into foods. The term tolerable daily intake (TDI) is often used for contaminants. 

Based on the calculated Maximum Dietary Exposure (MDE) of PAEs, and the Non Observed Adverse Effect Level (NOAEL) calculated from the available toxicology evidence, mainly hepatic, renal changes and reproductive toxicity in animals [88, 89,130-133], and making an uncertainty factor between 100 and 200, the EFSA panel calculated the Tolerable Daily Intake (TDI) for DBP, BBP, DEHP,... 

Table 4 Estimated daily intakes (EDI) of phthalates based on the geometric mean values for urinary metabolites estimated by David [137] for CDC data measured in 289 US individuals [138] and the tolerable daily intake (TDI) values calculated by EFSA [62], CSTEE [134], and MHLW [68], as well as the reference dose of phthalates (RfD) calculated by EPA [136] (in pg/kg b.w./day)...

The provisional tolerable daily intake (TDI) values proposed by the European Food Safety Authority (EFSA 2008) and Health Protection Agency (HPA 2009) amount to 150 ng/kg body weight (bwt)/d and 300 ng/kg bwt/d, for PFOS and PFOA, respectively. 

Related terms Reference Dose, Tolerable Daily Intake. 

The development of regulatory standards derived from a standard such as, e.g., the Tolerable Daily Intake or a Reference Dose, is addressed in Chapter 9. 

Acceptable/Tolerable Daily Intake is Estimated maximum amount of an agent, expressed on a body mass basis, to which an individual in a (sub) population may be exposed daily over its lifetime without appreciable health risk. ... 

For threshold effects, a Tolerable Daily Intake (TDI) is calculated by dividing the NOAEL (or LOAEL) for the critical effect(s) with an overall UF. The current practice according to the D-EPA in relation to the setting of quality criteria for chemical substances in soil, drinking water, and ambient air is to divide the overall UF into three categories (D-EPA 2006) ... 

Renwick (1995) discussed the possible rationale for the use of an additional safety factor for nature of toxicity in the estimation of Acceptable/Tolerable Daily Intake (ADI/TDI) values, including a survey of the historical use of such a factor. He concluded that the principal rationale for an additional factor for nature of toxicity is to provide a greater degree of separation of the ADI/TDI from the NOAEL observed in animal studies. In scientific terms, it was recognized that there are a number of uncertainties in extrapolating from high-dose animal studies to sensitive... 

Renwick, A.G. 1995. The use of an additional safety or uncertainty factor for nature of toxicity in the estimation of acceptable daily intake and tolerable daily intake values. Regul. Toxicol. Pharmacol. 27 3-20. 

Often, the output of the hazard (effects) assessment (e.g., the NOAEL) leads directly to the establishment of a regulatory standard, for example the derivation of an acceptable or tolerable daily intake (ADI/TDI) (Section 5.12) for a chemical in relation to a specific use category such as, e.g., pesticide, biocide, food additive, food contact material, etc. 

Guidance values are developed from a standard such as, e.g., an Acceptable/Tolerable Daily Intake (ADI/TDI), and Reference Dose/Concentration (RfD/RfC). For threshold effects, the standard is derived by dividing the No-Observed-Adverse-Effect Level (NOAEL) or Lowest-Observed-Adverse-Effect Level (LOAEL), or alternatively a Benchmark Dose (BMD) for the critical effect (s) by an overall assessment factor, described in detail in Chapter 5. For non-threshold effects, the standard is derived by a quantitative assessment, described in detail in Chapter 6. 

The section on derivation of guideline values using a tolerable daily intake (TDl) includes criteria for derivation of a TDI from a NOAEL or LOAEL by application of uncertainty factors these criteria are comparable to the principles outlined in Chapters 4 and 5 in this book. The guideline value is then derived from the TDl as follows ... 

QCasw is the quality criterion for air, soil, or drinking water TDI is the tolerable daily intake expressed as mg/kg bw/day V is the body weight (bw) in kg... 

New advances in boron nntrition research shonld include better characterization of the mechanisms through which boron modulates immune function and insulin release (Hunt 1998). Epidemiological studies should be initiated to identify health conditions associated with inadequate dietary boron (Sutherland et al. 1998). Finally, Dourson et al. (1998) recommend more research on uncertainty factors used in establishing tolerable daily intake values for the protection of human health, with emphasis on variations in interspecies and intraspecies differences in resistance to boron. 

The NOAEL, LOAEL or BMD approach can be used to calculate a guidance or reference level of exposure below which no adverse effects above background would be expected. These guidance levels include reference dose (RfD), acceptable daily intake (ADI) and tolerable daily intake (TDI). 

For food contaminants, the parameter is the tolerable daily intake (TDI). The tolerable daily intake (TDI) is an estimate of the daily intake of the chemical, which can occur over a lifetime without appreciable health risk. 

The elevated toxaphene levels in Lake Superior have social and economic impacts as well. The 2003 Guide to Eating Sport Fish published by the Ontario Ministry of Environment and Energy [158] indicates fish consumption advisories for Lake Superior lake trout due to toxaphene levels. As a result of the high toxaphene levels, the Ontario Ministry of Natural Resources has restricted sale with Ontario (but not the export) of large lake trout harvested from Lake Superior as of 1995. An assessment of toxaphene levels in Lake Superior fish fillets by Health Canada concluded that consumption of lake trout, salmon, longnose sucker and whitefish muscle from northwestern areas of the lake should be limited to one or two meals per month (55-135 g/week) based on a provisional tolerable daily intake of 0.2 pg/g body wt/day [159]. 

For many substances the body s own mechanisms for de-toxification and repair mean that low doses of some chemicals can be tolerated without experiencing any adverse effects. However, once a certain threshold has been exceeded then the degree of adverse effect is related to the dose. The highest dose at which no adverse effects are observed in the most susceptible animal species is identified at the No Observed Adverse Effect Level (NOAEL). The NOAEL is used as the basis for setting human safety standards for contaminants, Provisional Tolerable Weekly Intakes (PTWIs) or Tolerable Daily Intakes (TDIs).1... 

The risk to health from chemicals in food can be assessed by comparing estimates of dietary exposure with recommended safe levels of exposure. For most metals and other elements, these are the Provisional Tolerable Weekly Intakes (PTWIs) and the Provisional Tolerable Daily Intakes (PTDIs) recommended by the Joint Expert Committee on Food Additives of the Food and Agricultural Organisation of the United Nations and the World Health Organisation International Programme on Chemical Safety (JECFA). The European Commission s Scientific Committee on Food has established other relevant safe levels. These are Acceptable Daily Intakes (ADIs) for chemicals added to food, and Tolerable Daily Intakes (TDIs) for chemical contaminants. The use of the term tolerable implies permissibility rather than acceptability. All the above recommendations are estimates of the amount of substance that can be ingested over a lifetime without appreciable risk, expressed on a daily or weekly basis as appropriate. 

It can be seen from Table 7.4 that the population dietary exposure to total arsenic for UK consumers has remained fairly constant. The dietary exposures for mean and 97.5th percentile adult UK consumers in 1997 were 0.12 mg/day and 0.42 mg/day respectively. Although these exposures are similar or greater than the JECFA Provisional Tolerable Daily Intake (PTDI) for inorganic arsenic of 0.002 mg/kg bodyweight, which is equivalent to 0.12 mg/day for a 60 kg person, these are estimated for total arsenic. As has been stated before, most of the arsenic in the diet is from fish and most of the arsenic in fish is in the less toxic organic forms. 

The 1997 dietary exposure estimates for mean and 97.5th percentile adult consumers were 0.12 mg/day and 0.21 mg/day respectively.10 These can be compared with the World Health Organization (WHO) Tolerable Daily Intake (TDI) of 5 /xg/kg bodyweight (equivalent to 0.3 mg/day for a 60 kg person). The time trend for population dietary exposures is given in Table 7.10. 

An expert group convened by the WHO Regional Office for Europe in 1990 recommended a Tolerable Daily Intake (TDI) of 10 pg/kg bodyweight for... 

As a result of their extensive use and their moderate resistance to degradation, phthalates are widely distributed in the environment and are often found at low levels in food. Tolerable Daily Intakes (TDIs) have been established by the EC... 

Table 8.5 Tolerable Daily Intakes for phthalate diesters...

Abbreviation Chemical name Tolerable Daily Intake (mg/kg bodyweight/day)... 

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