The Russian system of chemicals management - Bef-de.org

3.1.4. Assessment of toxicological properties
The full assessment of toxicological properties of the substance comprises various endpoints,
which are comparable to those assessed for classification purposes, e.g. under
the GHS regulation. If data is already available (provided by registrant, available in literature
or databases on substance properties) it is used in the assessment. If information is
missing, respective studies are conducted. Methodological guidelines used to determine
toxic properties of substances are listed here in Annex II.
One of the main purposes of the assessment is to establish maximum permitted concentrations
(MPC) of a substance for various environmental compartments (air, water, soil) 13 .
Taking into account the scope of this document the methodological guideline on setting
hygienic norms for water bodies used for bathing and extracting drinking, and household
water (МU 2.1.5.720-98, replacing earlier version from 1975) is reviewed more in detail.
Maximum permissible concentration for household, cultural, and general water use
(MPC w
). The MPC w
is a concentration of a harmful substance in the water, below which
no direct or indirect adverse effects on human health should occur (if continuously being
exposed over the lifetime), or on the health of the next generations, and which should not
worsen hygienic conditions of the water use.
The development of an MPC for a substance consists of 6 stages (presented in Table 1). At
each stage it is carefully assessed, which further investigations are necessary. There are several
calculation methods available at each stage to estimate toxicity parameters and thoroughly
plan the next stages of the assessment. Stages 2-4 can be used both for the substance and its
degradation products (degradation products are chemically identified in stage 3).
Table 1: Stages of development of hygienic MPC for water bodies used for extracting drinking,
bathing and household water
No. Stage Investigations performed
1 Preliminary decision Literature and database research on substance properties, potential
biological and pharmacological effects. Studying the production process
and/or the use of the substance.
Preliminary calculation of hygienic parameters according to physicochemical
parameters, MPC assigned for other media and in other countries,
including ‘read-across’ data of similar substances.
2 Express estimation Estimation of a substance impact on organoleptic properties of water
and sanitary conditions of water bodies. Investigation of potential for
degradation. Stability category is assigned.
Testing acute toxicity parameters, including finding species, sex and
age specific differences in sensitivity to a substance. Calculation parameters
of chronic toxicity according to DL 50
(average lethal dose),
TL 50
.(average time of lethality) and combined mathematical models.
Assigning hazard class for a substance.
13 They are not ecotoxicological endpoints, but assigned from perspective of human health
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