6.3 Hazard Identification (Step 1)
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6.3.2 Environmental Toxicity
While risk assessment in regard to human health aims to protect everyone (including
the most vulnerable), a risk assessment to protect the environment rather aims to
protect entire ecosystems and simply cannot test each of the millions of species
of fauna and flora that exist on Earth. Instead, a primary estimation of the
environmental toxicity of a chemical is often carried out by testing aquatic species.
In particular, testing is frequently mandated on algae, daphnia, and fish, which
represent three distinct trophic levels.
Adverse effects to screen for in the environment can include, for example,
reduction of an organism’s survival, growth, or reproduction rates. Environmental
toxicity can be categorized into:
• Aquatic toxicity: Includes toxic effects on aquatic ecosystems in, for example,
rivers, lakes, and oceans. Normally used as the first proxy measure for general
environmental toxicity.
• Sediment toxicity: Includes toxic effects on organisms that exist within the
sediment.
• Terrestrial toxicity: Covers toxic effects on terrestrial animals, plants, and
microorganisms.
• Technical ecosystem toxicity: Includes toxic effects on man-made ecosystems,
primarily concerning the health of microorganisms in biological wastewater
treatment plants. Toxic effects on such microorganisms can affect the cleaning
performance of the plant and therefore pose a risk to the natural environment.
Just as for human toxicity, environmental toxicity includes both acute and
chronic effects. Following the GHS, Fig. 6.3 illustrates how the acute and chronic
toxicities of a substance are categorized into different levels of hazard for the aquatic
environment depending on data availability and the substance’s degradability. In
addition to considering available data to determine the LC 50 or EC 50 values, the
categorization also considers chronic effects described by the lowest concentration
at which no effect is observed in the studied species. This is known as the no
observed effect concentration (NOEC). The published guidelines for the GHS provide many more helpful details and specific step-by-step instructions for reaching
these categorizations (UN, 2019).
In practice, this testing can be resource-intensive for both human and environmental toxicities, and investment needs to be made to ensure testing creates highquality data and is thoroughly documented. Inspection has shown that the majority
of submitted REACH registration dossiers lack important safety information about
the chemicals they describe (ECHA, 2017a, 2019).
113
6.3.2 Environmental Toxicity
While risk assessment in regard to human health aims to protect everyone (including
the most vulnerable), a risk assessment to protect the environment rather aims to
protect entire ecosystems and simply cannot test each of the millions of species
of fauna and flora that exist on Earth. Instead, a primary estimation of the
environmental toxicity of a chemical is often carried out by testing aquatic species.
In particular, testing is frequently mandated on algae, daphnia, and fish, which
represent three distinct trophic levels.
Adverse effects to screen for in the environment can include, for example,
reduction of an organism’s survival, growth, or reproduction rates. Environmental
toxicity can be categorized into:
• Aquatic toxicity: Includes toxic effects on aquatic ecosystems in, for example,
rivers, lakes, and oceans. Normally used as the first proxy measure for general
environmental toxicity.
• Sediment toxicity: Includes toxic effects on organisms that exist within the
sediment.
• Terrestrial toxicity: Covers toxic effects on terrestrial animals, plants, and
microorganisms.
• Technical ecosystem toxicity: Includes toxic effects on man-made ecosystems,
primarily concerning the health of microorganisms in biological wastewater
treatment plants. Toxic effects on such microorganisms can affect the cleaning
performance of the plant and therefore pose a risk to the natural environment.
Just as for human toxicity, environmental toxicity includes both acute and
chronic effects. Following the GHS, Fig. 6.3 illustrates how the acute and chronic
toxicities of a substance are categorized into different levels of hazard for the aquatic
environment depending on data availability and the substance’s degradability. In
addition to considering available data to determine the LC 50 or EC 50 values, the
categorization also considers chronic effects described by the lowest concentration
at which no effect is observed in the studied species. This is known as the no
observed effect concentration (NOEC). The published guidelines for the GHS provide many more helpful details and specific step-by-step instructions for reaching
these categorizations (UN, 2019).
In practice, this testing can be resource-intensive for both human and environmental toxicities, and investment needs to be made to ensure testing creates highquality data and is thoroughly documented. Inspection has shown that the majority
of submitted REACH registration dossiers lack important safety information about
the chemicals they describe (ECHA, 2017a, 2019).