Historical exposure to chemicals reduces tolerance to novel chemical stress in Daphnia (waterflea)

Abstract

Anthropogenic chemicals used in most production processes are transported globally, and usually end up in the environment as unintentional pollutants that harm humans and damage the environment (Wang et al., 2020). Until the last few decades, there were no comprehensive assessments of the risk and impact of anthropogenic chemicals on wildlife and humans (Dulio et al., 2018) and premarket toxicity has not been evaluated (Brooks et al., 2020).Although toxicology has modernized significantly (Choudhuri et al., 2018), predictive frameworks rely on acute toxicity estimates that are limited in scope and do not necessarily reflect realistic

Daphnia as a Sentinel Species for Environmental Health Protection: A Perspective on Biomonitoring and Bioremediation of Chemical Pollution

“…In addition, they share human disease genes that are ancestral in animal genomes and shared across phylogenetically distant species. − The water flea Daphnia shares many advantages with these model species. Daphnia has a short generation time enabling experimental manipulation of large populations, has growing genomics resources, − and shares many ancestral gene families with humans Daphnia has additional properties that surpass traditional biomedical model species.…”

“…First, we benchmark Daphnia against other biological agents, i.e., algae and bacteria. Second, we use the properties of Daphnia as a fast-evolving organism to environmental pollution , to identify strains with higher decontamination abilities that can be tailored to different wastewater sources.…”

“…(A) Removal efficiency of known concentrations of 16 pharmaceuticals (ng/L) by bacteria (blue), algae (orange), and Daphnia (gray). (B) Abatement of an industrial chemical (PFOS; μg/L), a biocide (atrazine; mg/L), and a heavy metal (arsenic; mg/L) by four strains of Daphnia resurrected from a sedimentary archive with different historical environmental backgrounds: LRV0_1 (2015), LRV8.5_3 (1985), LRV12_3 (1955), and LRII36_1 (1900) (ref ). The abatement of chemicals is shown after 48 h of exposure and compared to a controlspiked medium without Daphnia (control).…”

“…This is relevant because different wastewater sources may contain different chemical cocktails. We capitalize on our previous work in which we studied fitness responses of four Daphnia strains resurrected from a sedimentary archive of a lake with a well-known history of chemical pollution. , The lake experienced no chemical exposure until the 1970s and high chemical exposure from 1975 onward. In our previous work, we showed that genotypes that were historically exposed to chemical stress showed reduced genomewide diversity and lower fitness when exposed to novel chemical stress.…”

“…This lower fitness was underpinned by reduced gene diversity at detoxification, catabolism, and endocrine genes. These results suggest potential lower tolerance to novel chemical stress and higher tolerance to recurring stress in experienced genotypes . Here, we study the removal efficiency of these strainstwo that were naïve to chemical stress (LRV12_3 and LRII36_1) and two that experienced historical chemical stress (LRV0_1 and LRV8.5_3; Figure )following 48 h of exposure to a metal (arsenic), a biocide (atrazine), and an industrial chemical (PFOS) .…”