Suitable test substances for proof of concept regarding infochemical effects in surface waters

Abstract

Abstract Background Infochemical effects have been defined as the manipulation of the odour perception of organisms by anthropogenic substances which may result in ecologically relevant behavioural disorder. However, the environmental relevance of infochemical effects has not yet been confirmed by experimental observations. This project aims to test for infochemical effects on chemical communication in water bodies with systematic experimental investigations. The first crucial step is to select suitable test substances. Repellents (PT 19 biocides) and odourants may be assumed to affect the response of aquatic populations and communities. These mostly polar and stable compounds may disturb chemical communication between organisms and may cause organismic effects like drift (downstream dislocation of e.g. crustacean and insect larvae in streams). Repellents enter surface waters mainly indirectly via wastewater discharges from sewage treatment plants or directly by being washed off from the skin and clothes of bathers. Results In this literature study, suitable chemicals were selected for confirmatory assessments of suspected infochemical effects by laboratory tests in a subsequent second part of the project. The use pattern and physico-chemical properties of the substances selected, in combination with their limited biological degradability, indicate potential aquatic relevance with possible chronic impact caused by disturbed communication. After due consideration of advantages and limitations, three PT 19 repellents appear suitable test compounds for proof of concept in the subsequent experimental part of the project: • DEET (CAS 134-62-3) • Icaridine (CAS 119515-38-7) • EBAAP (CAS 52304-36-6) Another promising candidate for infochemical effects is isophorone (CAS 78-59-1), a natural attractant and an anthropogenic high production volume solvent. Conclusions Four chemicals were selected with the expectation that they may be suitable test substances for experimental proof of concept of infochemical effects in the subsequent part of the project. The experimental results may then help to answer the question of whether PT 19 biocides and other odourants entering aquatic ecosystems give rise for concern about potential infochemical effects.