ISO/TC 190/SC 7/WG 4 - Human exposure

This document provides guidance on the type and extent of soil characterization necessary for the evaluation of human exposure to substances present in possibly leading to adverse effects. It does not provide guidance on: — the design or selection of numerical models that can be used to estimate exposure; — potential exposure to radioactivity, pathogens or asbestos in soil. Background information is provided on human health related to exposure to soil and the influence on exposure via different pathways. NOTE 1 For convenience "soil" in this document also includes "soil material" unless stated otherwise. NOTE 2 Overall exposure can be due to potentially harmful substances (PHSs) in soil, groundwater and air. Exposure to those in soil can be direct (e.g. through inhalation, ingestion, cutaneous contact), or indirect (through the consumption of plants or animals that have taken up substances of concern). NOTE 3 The evaluation of the possible impact on human health of potentially harmful substances is most commonly required when these are present as a result of human activity (e.g. on old industrial sites) but can sometimes be required when they are present naturally. NOTE 4 Soil characterization precedes the assessment of the compatibility between soil and its use (i.e. soil quality assessment). Tools such as a conceptual site model (CSM) and health risk assessment can be used to aid this assessment. NOTE 5 Soil characterization can be used to develop an overview of population exposure to soil. Other International Standards are available that can aid the characterization of other media (e.g. surface and groundwater), in terms of their possible adverse effects on humans.

This document deals with the assessment of human exposure from ingestion of soil and soil materials. It specifies a physiologically based test procedure for the estimation of the human bioaccessibility of metals from contaminated soil in connection with the evaluation of the exposure related to human oral uptake. The method is a sequential extraction using synthetic gastrointestinal fluids and can be used to estimate oral bioaccessibility. Soils or other geological materials, in sieved form, are extracted in an environment that simulates the basic physicochemical conditions of the human gastrointestinal tract. This document describes a method to simulate the release of metals from soil and soil materials after passage through three compartments of the human gastrointestinal tract (mouth, stomach and small intestine). It produces extracts that are representative of the concentration of potentially harmful elements in the human gastrointestinal tract for subsequent chemical characterization. NOTE 1 Bioaccessibility can be used to approximate oral bioavailability. NOTE 2 The test has been validated for arsenic, cadmium and lead in an interlaboratory trial. The method has been in vivo validated to assess the oral bioavailability of arsenic, cadmium and lead.

ISO 11504:2017 gives guidelines with regard to the choice of fractions and individual compounds when carrying out analysis for petroleum hydrocarbons in soils, soil materials and related materials, including sediments, for the purpose of assessing risks to human health, the environment and other possible receptors. Since many products based on petroleum hydrocarbons often contain substances that are not hydrocarbons, the recommendations also encompass such compounds where relevant. ISO 11504:2017 also includes relevant background information on which the recommendations are based together with guidance on the use of the fractions recommended in the assessment of risk. ISO 11504:2017 does not set criteria or guidelines for use as assessment criteria, since this is typically a national or regional regulatory issue. This document also does not include recommendations as to the specific model for the exposure assessment or the specific parameter values to be used; with respect to guidance on this matter, reference is made to ISO 15800.

ISO/TS 17924:2007 deals with the assessment of human exposure from ingestion of soil and soil material. ISO/TS 17924:2007 gives guidelines to be used when choosing a physiologically based test procedure for the estimation of the human bioaccessibility/bioavailability of metals from contaminated soil in connection with the evaluation of the exposure related to human oral uptake. Suggestions are made for the use of as many generic-method elements as possible, but it is important that the choice of method be based on the needs of the specific investigation. Methods that are validated for specific metals and/or contexts are highlighted.

ISO 15800:2003 gives guidelines on the kind and extent of soil characterization necessary for the evaluation of human exposure to substances that can cause adverse effects. The possibilities of standardizing the calculations used for the assessment of human exposure are not included in ISO 15800:2003. The information needed for evaluation of human exposure to contaminants leached from soil to surface and/or groundwater or transferred by runoff is not included in ISO 15800:2003. Aspects related to radioactivity and pathogens in soil and potential human exposure hereto are also not included in ISO 15800:2003.