GB/T 34708-2017General principles for risk assessment of chemicals (English PDF)

2.1 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

2.1.1 hazard

chemicals' inherent characteristics to likely cause undesirable effects when exposed to living bodies, systems or (sub-) population

2.1.2 risk

possibility that unfavourable influences will happen when chemicals are exposed to living bodies, systems or (sub-) population under specific environment

2.1.3 risk assessment

a process of calculating or estimating chemicals risk on targeted living body, systems or (sub-) population and the uncertainties under specific exposure conditions

Note: risk assessment includes four steps: hazard identification, hazard characterization, exposure assessment and risk characterization. Intrinsic characteristic of chemicals and characteristic of targeted boisystem shall be taken into consideration.

2.1.4 hazard assessment

a process of determining potential hazard when living body, systems or (sub-) population are exposed to chemicals

Note: hazard assessment includes hazard identification and hazard characterization. It concerns only the hazards and excludes exposure assessment and risk characterization which are included in risk assessment.

2.1.5 hazard identification

identifying types and nature of unfavourable influences of chemicals likely exerted on living body, systems or (sub-) population

Note: hazard identification is the first stage of both hazard assessment and risk assessment.

2.1.6 hazard characterization

describing inherent characteristics of chemicals likely causing potential hazards and influence qualitatively or quantitatively (if feasible)

Note: hazard characterization includes dose-reaction assessment and uncertainties accompanied. Hazard characterization is the second stage of both hazard assessment and risk assessment.

2.1.7 exposure assessment

assessing exposure of living body, system or (sub- )population to chemicals (and their derivatives)

Note: exposure assessment is the third stage of risk assessment

2.1.8 risk characterization

making qualitative or quantitative decision for the probability of chemicals causing known /potential unfavourable influences living body, system or (sub-)population and its uncertainties under specific exposure conditions

Note: risk characterization is the fourth stage of risk assessment.

2.1.9 uncertainty

incomplete information for living body, system or (sub-) population studied at present or in the future

2.2 Abbreviation

For the purposes of this document, the following abbreviations apply.

DNELs: derived no effect level

LOAEL: lowest observed adverse effect level

NEL: no effect level

NOAEL: no observed adverse effect level

NOEL: no-observed effect level

PEC: predicted environmental concentration

PNEC: predicted no effect concentration

TDI: tolerable daily intake

TLV: threshold limit value

3.1 Effective information

Prior to assessment, widely collect relevant information; during assessment, use the most reasonable and credible scientific information available at present and ensure the information is reliable, related, applicable and real-time.

3.2 Comprehensive assessment

During assessment, all the possible hazards (such as acute and chronic risks, cancerous and non-cancerous risks, risk for human health and environment) shall be considered. Assess with qualitative or quantitative method or their combination. In case suitable data are obtained, give priority to quantitative evaluation method. Consideration shall be given to not only all the population, but also a susceptive /high risk group specially liable to this risk and/or a higher exposure.

3.3 Comprehensive measure

During the assessment, consideration shall be given to development level of science and technology and knowledge, existing scientific data /information as well as relevant administrative statutes.

5.1 Preparation and information collection before assessment

Before assessment, it is necessary to determine the risk assessment range, learn relevant information, and determine anticipated targets.

Information to be collected mainly includes: physico-chemical properties, health hazard and environment hazard information, use, possible exposure pathways, usage quantity and other relevant information; relevant domestic and foreign laws and regulations, standards, on record literatures, and expertise, etc.

5.2 Risk assessment

5.2.1 Exposure assessment

5.2.1.1

Exposure assessment includes environment (water environment, terrestrial environment and air) or population (i.e. workers, consumers or people under indirect contact via the environment) exposure or potential chemical exposure assessment, including exposed quantity, frequency, period, duration and pathway.

5.2.1.2

During exposure assessment, one or more kinds of exposure scenarios are first established generally, and then exposure assessment is carried out for varied exposure pathways under the use condition described for the exposure scenario. Establishment of exposure scenario (with definite information concerning chemicals production and use condition) is of crucial importance for determination of exposure level. Exposure assessment shall cover all exposure concerning chemicals hazard recognized in the hazard assessment, including chemicals production, all determined uses, and the stages of the whole related life cycle under consideration, and exposure level shall be determined for each exposure scenario.

5.2.1.3

Generally, the population likely to be exposed to chemicals is classified into the following three categories, with the expected exposure pathways and characteristics as shown in Table 1.

Table 1 Expected Exposure Pathways and Characteristics

Category of population Exposure pathways Exposure time Remarks

Workers (occupational exposure) Generally, inhalation and percutaneous exposure Working time (e.g. 8 hours per day, 5 days per week) Relatively healthy population

Consumers (exposed to retail consumer products) Peroral, inhalation and/or percutaneous exposure Intermittent exposure, to be estimated It may be hard to control exposure of this group of population

Population indirectly exposed via the environment Peroral, inhalation and/or percutaneous exposure 24 hours per day, 365 days per year This group contains the weak and the unhealthy population, e.g. children and the elderly 5.2.1.4 With regard to environmental exposure assessment, chemicals discharge types (i.e. point source discharge, surface source discharge, continuous discharge, semi-continuous discharge or intermittent discharge) shall be especially considered, which has important influence on duration and frequency of chemicals exposed to the environment. Generally, monitoring data, if any, shall be firstly used in estimation.

5.2.1.5

Generally, exposure assessment on the population under indirect exposure via the environment shall follow the following procedures:

a) Assess concentration of chemicals in the contactant, e.g. food, water, air and soil;

b) Assess uptake rate of each kind of medium;

c) Determine the intake according to concentration and intake conditions of chemicals in various media (where necessary, bio-availability factors of the intake pathways shall be taken into consideration).

5.2.1.6

Generally, human exposure can be assessed according to representative monitoring data and/or by model calculation based on similar use, exposure mode or characteristic chemicals information. Physicochemical properties (e.g. vapor pressure, pH value and n-octanol/water distribution coefficient) of chemicals shall be taken into consideration for estimating discharge condition and potential human exposure, assessing toxicity testing scheme, and analyzing adsorption degree of chemicals via different exposure pathways. Active data of chemicals shall be taken into consideration for estimating exposure of chemicals to human body.

5.2.1.7

Exposure data reliability depends on suitability of the technologies adopted, as well as sampling, analysis and established scheme quality and strategy. Additional weight shall be given to the optimal and the most reliable data. In the case of poor data acquisition, assessment is generally developed based on uptight assumption.

5.2.2 Hazard assessment

5.2.2.1

Hazard identification covers health hazard and environment hazard data (epidemiology survey data, clinical study data, laboratory data), and structure - activity relationship information, etc.

5.2.2.2

See Annex A for classification of chemical hazards.

5.2.2.3

The physical and chemical toxicological properties and environmental toxicology information of chemicals, which can be obtained from a number of databases, may be used to classify the chemicals according to their hazard type and degree. Classification information of chemicals is an important source of hazard information, which can generally be acquired from the product's safety data sheet (SDS) or chemicals labels and SDS.

5.2.2.4

For chemicals whose hazard information is more difficult to acquire and their potential damages may be evaluated by various methods, scientific literatures, scientific observation, experimental research and physical properties based and structure-activity relationships may be applied for inference.

5.2.2.5

Main sources of information for hazard identification are as follows:

a) safety data sheet for chemical products (SDS) supplied by the manufacturer or supplier or labels;

b) test/detection;

c) published laws, regulations and standards;

d) scientific and technical data;

e) accident report;

f) expert opinions;

g) miscellaneous.

5.2.3 Hazard characterization

5.2.3.1

Hazard characterization includes selection of critical data set and determination of hazard behavior mode/mechanism and dose-reaction (effect) relationship, etc.

5.2.3.2

Physical effects such as burning or explosion are more easily determined, while toxicological effects are more difficult to determine due to limitations of human related data and they are usually obtained by the following methods:

a) human observation data, including case report, epidemiologic study and human test under certain circumstances;

b) animal/plant toxicity test;

c) structure-activity relationship assessment.

5.2.3.3

For most chemicals, the NELs derived from animal test researches may be converted into NELs (PNECs or DNELs) for predicting or assessing human health or environment; generally, an uncertainty factor of 10~10 000 is used.