Effects of leaf litter extracts from four tree species on aquatic invertebrates: an ecotoxicological risk assessment approach

Abstract

Upper reaches of temperate streams and oligotrophic lakes depend trophically on the organic matter coming from the surrounding watershed. These aquatic ecosystems accumulate particulate and dissolved organic matter, and chemical compounds liberated from decomposing leaves or from the leachates of leaf litter. These materials supply a wide range of chemical compounds, which may serve as food, but also cause ecotoxicological effects on aquatic organisms. However, this ecotoxicological risk has been amply ignored, especially for freshwater invertebrates. The aims of our study are:1) to assess the direct toxicity of aqueous extracts of leaf litter from two native (Populus alba, Fraxinus angustifolia) and two tree species exotic to Europe (Robinia pseudoacacia, Ailanthus altissima) on a pelagic and a benthic species of model aquatic invertebrates: Daphnia magna (Cladocera) and Potamopyrgus antipodarum (Mollusca) and 2) to estimate the ecotoxicological risk of the leaf litter extracts to lacustrine ecosystems using different simulated scenarios of shallow lakes. For both invertebrate species, we assessed the effective concentration of leaf extract causing an effect on 50% of the population (EC50) by means of laboratory bioassays. Our results show that the extracts of leaf litter from all the tested trees have a potential ecotoxicological risk in some scenarios, which is independent from the geographic origin of the tree species.

Cigarette butt effects on diatom health in a stream ecosystem

“…Leaf leachate can be toxic to aquatic organisms (e.g., Beleza et al 2019;Manusadžianas, 2014). Whereas toxicity may be evident in laboratory toxicity tests, by extrapolating this toxicity to small lakes, Alonso et al (2020) concluded that leachates from natural leaf fall would have little or no toxic effects on aquatic invertebrates.…”

In Vitro Screening of Ecotoxic and Cytotoxic Activities of Ailanthus altissima Leaf Extract against Target and Non-Target Plant and Animal Cells

“…To our knowledge, no study regarding the A. altissima toxicity towards A. salina has been published so far. The toxicity of fresh A. altissima leaves litter extracts has been tested towards another aquatic invertebrate, D. magna , showing a median effective concentration (EC 50 ) of 10.1 g/L of air-dried leaf, at 96 h [ 27 ]. In our study, the sensitivity of A. salina to A. altissima extract increased with time, the highest one being registered after 48 h, similar to other studies on natural extracts but from different species, e.g., from marine organisms [ 81 ].…”

“…Ecotoxicity is usually conducted towards crop plants and organisms from aquatic ecosystems. Ecotoxicological studies have revealed some effects of A. altissima aqueous extract on wheat [21] or other plants' germination [22][23][24][25][26], and on the mortality of the Daphnia magna crustacean [27]. Cytotoxicity on mammalian cells is usually investigated either on cell cultures exposed to natural products when referring to their safety to non-target organisms, or screening tests on tumor cells when searching for potential bioactive agents.…”