Consumer exposure estimates

ECHA (2010) Guidance on information requirements and chemical safety assessment -Chapter R.15 Consumer exposure estimation. Version 2... 

These are estimates of dietary exposure to inorganic contaminants for individuals who eat average amounts of food (i.e. mean consumers) and those who eat more than average (i.e. upper range (97.5th percentile) consumers) and are based on consumption data from the UK National Adult Dietary Survey (NADS).4 They are calculated using the mean upper bound concentrations of specific contaminants in each food group and the consumption data from the NADS. Consumer exposure estimates are less suitable for following trends in exposure than population estimates as they are based on consumption data from the NADS which was carried out only once in 1986 and 1987 and is not updated... 

ECHA. 2012. Guidance on Information Requirements and Chemical Safety Assessment. Chapter R.15 Consumer Exposure Estimation. ECHA-10-G-03-EN. Available at http //echa.europa.eu/documents/10162/13632/information requirements rl5 en.p>df (accessed November 29, 2013). 

Though only an estimate, a maximum consumer exposure has been established at approximately 37 mg/person/day when DOSS is used as a food additive. In medical use maximum consumption of 200 mg/day is suggested [76]. The pharmacological and side effects of DOSS have been studied by many authors [77-81]. 

Based upon the various sources of adult consumer exposure to organotin compounds (section 6) and the TDI values derived above, it is possible to estimate the relative exposure from the various organotin compounds expressed as a percentage of the TDI values. The exposure calculations in section 6 were based on a realistic worst-case exposure assessment. Table 26 presents the results of this risk characterization. 

The dangerous properties of acute toxicity, irritation, corrosivity, sensitisation, repeated-dose toxicity and CMR are evaluated in terms of their potential toxic effects to workers, consumers and man exposed indirectly via the environment, based on the use for each stage in the lifecycle of the substance from which exposure can occur. Risk assessment is also required if there are reasonable grounds for concern for potential hazardous properties, e.g., from positive in vitro mutagenicity tests or structural alerts. The risk assessment involves comparing the estimated occupational or consumer exposure levels with the exposure levels at which no adverse effects are anticipated. This may be a quantitative risk assessment, based on the ratio between the two values, or a qualitative evaluation. The principles of human health risk assessment are covered in detail by Illing (a.30) and more briefly in Chapter 7 of (73). 

Reliable, measured values are preferred, and should be used when available. Measured values or estimates of water solubility and vapor pressure are important in evaluating whether a chemical will dissolve in water or exist as a vapor at ambient temperature, and are used to estimate worker and consumer exposures. Measured data or estimates of biodegradation, sorption, and volatilization potential are used to predict removal in wastewater treatment. Information on decay rates in the... 

The risk characterization is carried out by quantitatively comparing the outcome of the hazard (effects assessment) to the outcome of the exposure assessment, i.e., a comparison of the NOAEL, or LOAEL, and the exposure estimate. The ratio resulting from this comparison is called the Margin of Safety (MOS) (MOS = N(L)OAEL/Exposure). This is done separately for each potentially exposed population, i.e., workers, consumers, and man exposed via the environment, and for each toxicological endpoint, i.e., acute toxicity, irritation and corrosion, sensitization, repeated dose toxicity, mutagenicity, carcinogenicity, and toxicity to reproduction. 

Cadby P.H., W.R. Troy, and M.G.H. Vey (2002). Consumer exposure to fragrance ingredients Providing estimates for safety evaluation. Regulatory Toxicology and Pharmacology 36 246-252. 

A key question here is whether the actual conditions of use will be those that are specified in the exposure scenario. For industrial uses of chemicals, where people have access to safety data sheets and are governed by health and safety and pollution control legislation, there is some hope that people will use the chemical in the way that the exposure scenario envisages. Even here, however, there are bound to be departures from the exposure scenario conditions people will not always wear protective equipment, or follow instructions, and accidents are bound to happen. Consumers, on the other hand, will usually not even know what chemicals a product contains, let alone have access to the details of the exposure scenario. Even if they had, there is no way that their following it and acting in the way it envisages could be enforced. There are therefore major uncertainties as to whether the exposure estimates derived from the exposure scenarios really represent the actual exposure of people and the environment to a chemical. 

In the exposure assessment stage, qualitative and quantitative evaluation of the likely intake of drug residues through food as well as exposure from other sources are performed. Estimating consumer exposure is based on the daily consumption of a particular food commodity combined with its content of veterinary drug residues. 

The conditions under which the drug is used need to be estimated as do acceptable residues linked to the level of acceptable risk to the consumer. The acceptable level of risk, which is determined in theory at the risk management stage, has already been expressed in terms of residues by the ADI under hazard characterization. Moreover, the elements considered for hazard identification, hazard characterization, and exposure assessment make it possible, for a given form of utilization of a particular substance, to establish a profile of residues in animal tissues and to associate this with a profile of consumer exposure. Comparison of this consumer profile and ADI indicates whether the mode of utilization of the substance is acceptable or not. Analysis of the different results of residue content in animal products then provides an indication of level of residues in one or several animal tissues, making it possible to differentiate between veterinary drug applications that do or do not permit compliance with the ADI. 

The JECFA PTWI for tin is 14 mg/kg body weight, equivalent to 120 mg/day for a 60 kg adult. Average dietary exposure has remained in the range 1.7-5.3 mg/day (Table 7.6). The dietary exposure estimates for mean and 97.5th percentile consumers were 1.9 mg/day and 6.3 mg/day respectively, well below the PTWI. 

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. 

A Total Diet Study carried out in the UK in 1993 detected low levels of a range of individual phthalates in composite samples of carcass meat, poultry, eggs and milk.69 Only low levels (generally < 0.07 mg/kg) were found. Total phthalate was determined (by conversion of any phthalate in the samples to dimethyl phthalate) in carcass meat, eggs, meat products, offals, poultry, fish, fats and oils, milk and milk products. Each food group was found to contain total phthalate in a range between 0.5 and 8.8 mg/kg. This difference may be due to the presence of phthalate monoester metabolites, which would be included in the analytes. The dietary exposures of even 97.5th percentile consumers were estimated to be within the TDIs for DEHP, BBP and DBP. 

The second part of any risk assessment requires an estimate of consumer exposure to the migrating substance. This depends on a number of factors ... 

At the present time, most US pesticide tolerances were established prior to the passage of FQPA. In assessing consumer risk from exposure to pesticides, the EPA first estimates consumer exposure. The maximum legal exposure to the pesticide is usually first calculated by assuming that... 

---