Pesticides

Common pesticide types

• Dissinfectants

• Antifouling paints

• Insecticides

• Preservatives

Quaternary ammonium disinfectants and antiseptics

❑Substantial increase in the use of disinfectants containing quaternary ammonium compounds (QACs) in healthcare and community settings during the COVID-19 pandemic. Quaternary ammonium disinfectants and antiseptics

❑There is increased concern that heavy use of QACs might cause bacteria to develop resistance to QACs or contribute to antibiotic resistance.

Inderect effects of pesticides

• predation

• Competition

• Habitat alterations

• Symbiosis, mutualisim, commensalism

Crittical recovery issue with pesticides

• Transient, short-term effects are accepted because of the “community recovery principle”

• “The Community Recovery Principle presupposes that an ecosystem can absorb and endure a certain amount of pollution because of ecological recovery processes.”

SPEAR pesticides (Species At Risk)

• SPEARpesticides (Species At Risk) is a trait based biological indicator system for streams which quantitatively links pesticide contamination to the composition of macroinvertebrate communities.

• SPEAR indicators have been developed for the retrospective ecological risk assessment of pesticides

• The approach uses species traits that characterize the ecological requirements posed by pesticide contamination in running waters. Therefore, it is highly specific and only slightly influenced by other environmental factors.

• SPEARpesticides is linked to the quality classes of the EU Water Framework Directive (WFD).

Pesticides summary

• Pesticides are the most thoroughly investigated group of environmental chemicals

• High regulation of pesticides

• Tiered approach

• Exposure often in pulses (spray events)

• Recovery in an ecological context is highly debatable, but nevertheless a cornerstone of the regulatory assessment of ecological impacts of pesticides

• Relation between simple single-species assays and advanced ecological assays is complex and depends (amongst others) on

– (Ecological) mode of action of the compounds

– Aim of the study (knowledge generation vs. risk assessment)

– Direct vs. indirect effects (ecological interactions)

Pesticide summary 2

• SPEAR pesticides is community bioindicator based on freshwater macroinvertebrates for retrospective ecological risk assessment of pesticides

• Several azole fungicides are considered emerging compounds > hazardous properties towards aquatic fungi

• Pesticide contamination occurs in form of mixtures in agricultural streams. Difficult to link pesticide exposure with effects on algal and microbies diversity.