We have developed a new terrestrial ecotoxicology component of the HazEL. The resulting framework expands HazEL beyond its existing human health, aquatic toxicity and fate structure by adding terrestrial receptor groups and endpoints relevant to biosolids land application and wastewater irrigation scenarios.
We have retained the same core HazEL parameter structure, including the main human toxicity, aquatic toxicity, and fate categories, the same broad distinction between GHS classification, endpoint data and exposure limits, and many of the same primary sources; ECHA, PPDB, US EPA CompTox, PubChem, etc., and water quality guideline sources. The principal continuity is that the human health and aquatic toxicity framework remains unchanged.
The changes incorporated are in the terrestrial ecotoxicity and fate sections:
Acute terrestrial ecotoxicity has been revised to become a detailed set of acute endpoints for earthworms, collembola, birds, honeybees, and plants.
Endocrine disruption has been added into the chronic terrestrial ecotoxicity section as an environmental endocrine disruptor parameter.
Chronic terrestrial endpoints have been expanded to include earthworms, collembola, birds, honeybees, soil mites and soil microorganisms.
The biosolids exposure limits and fate rows have also been refined, with more specific biosolids guidance sources added and water monitoring separated from biosolid concentration data.
We have undertaken two independent technical reviews:
to confirm that the proposed terrestrial ecotoxicity framework is appropriate, and
to test for any implementation and quality-assurance issues.
These refinements will improve user confidence in the system and ensure that HazEL remains practical for screening purposes while maintaining a clear audit trail for future update and scrutiny.