Cause-effect pathway

The impact pathways for ecotoxicity builds on the combination of an environmental fate factor, an ecological exposure factor, an ecotoxicity effect factor, and an ecotoxicity-effect damage factor. The fate factor indicates the distribution and transformation of chemicals in the environment, the exposure factor relates dissolved to total chemical mass in the environment, the ecotoxicity effect factor indicates potential ecotoxicity effects per unit of dissolved chemical mass in the environment, and the damage factor finally relates potential effects to damages on ecosystem quality.

Included are organic chemical substances and metal ions.

Cause-effect chain for ecotoxicity-related damages on ecosystem quality (and human health) from chemical emissions

Modeling approach

Global or (sub-)continental average characterization factors are modeled based on the assumption of linearity between exposure and species response.

Value choices

To maintain consistency with other impact categories, a time horizon of 100 years is set for the high level of robustness scenarios.

Spatial variability

The default are global average characterization factors for different emission compartments (local scale: indoor and urban air; continental and global scale: rural air, agricultural and natural soil, freshwater and marine water).

In addition, characterization factors are available for 8 continental regions (North America; Latin America; Europe; Africa and Middle East; Central Asia; Southeast Asia; Northern regions; Oceania) and 16 sub-continental regions (Central Asia; Indochina; Northern Australia; Southern Australia and New Zealand; Southern Africa; North, West, East and Central Africa; Argentina+; Brazil+; Central America & Caribbean; USA and Southern Canada; Northern Europe and Northern Canada; Europe; East Indies and Pacific; India+; Eastern China; Japan and Korean Peninsula).

Global average characterization factors for freshwater and marine water ecotoxicity for metal ions are based on, respectively, averaging factors from 7 European freshwater archetypes representing the variation of freshwater chemistries in Europe mainland, and from 64 large marine ecosystems.

Characterisation factors

The ecotoxicity-related ecosystem quality characterization factor at damage (endpoint) level,CF [PDF m³_{exposure medium} d/kg_emitted], represents the potentially disappeared fraction (PDF) of species integrated over the volume of exposed compartment (e.g. freshwater) or medium (e.g. soil pore water) and time per kg of chemical emitted to a given environmental compartment, and is derived as

FF [kg_{in compartment}/(kg_emitted/day)] is the fate factor relating the chemical mass in a given environmental compartment to the chemical mass emitted per day into the same or another environmental compartment. 𝑋𝐹 [kg_bioavailable/kg_{in compartment}] is the ecosystem exposure factor representing the bioavailability of chemicals to organisms in the environmental compartments considered for ecotoxicity. EF [PAF m³_{exposure medium}/kg_bioavailable] is the ecotoxicity effect factor relating the potential of the bioavailable fraction of a chemical to cause toxic effects to an exposed ecosystem expressed as potentially affected fraction (PAF) of species in the exposed ecosystem integrated over the compartment or medium volume to the chemical mass in the environmental compartment surrounding the exposed ecosystem. and DF [PDF/PAF] is the ecosystem damage factor relating the potentially disappeared fraction of species to the potentially affected fraction of species.

Out of 3104 substances included in the USEtox characterization model adapted for LC-Impact, ecotoxicity characterization factors for freshwater, marine water and terrestrial soil ecotoxicity are available for 27 metal ions and 2499 organic substances.