Sensitivity of hypogean and epigean freshwater copepods to agricultural pollutants

Abstract

Widespread pollution from agriculture is one of the major causes of the poor freshwater quality currently observed across Europe. Several studies have addressed the direct impact of agricultural pollutants on freshwater biota by means of laboratory bioassays; however, as far as copepod crustaceans are concerned, the ecotoxicological research is scarce for freshwater species and almost nonexistent for the hypogean ones. In this study, we conducted a comparative analysis of the available literature data on the sensitivity of freshwater copepods to agricultural pollutants. We also assessed the acute and chronic sensitivity of a hypogean and an epigean species, both belonging to the Crustacea Copepoda Cyclopoida Cyclopidae, to two N-fertilizers (urea and ammonium nitrate) and two herbicides (ARIANE TM II from Dow AgroSciences LLC, and Imazamox), widely used for cereal agriculture in Europe. According to the literature review, freshwater copepods are sensitive to a range of pesticides and N-fertilizers. Ecotoxicological studies on hypogean species of copepods account only one study. There are no standardized protocols available for acute and chronic toxicity tests for freshwater copepods, making comparisons about sensitivity difficult. From our experiments, ionized ammonia proved to be more toxic than the herbicide Imazamox, in both short and chronic bioassays. Urea was the less toxic chemical for both species. The hypogean species was more sensitive than the epigean one to all chemicals. For both species and for all tested chemicals, acute lethality and chronic lethality were induced at concentrations higher than the law limits of good water body quality in Europe, except for ionized ammonia, which provoked the chronic lethality of the hypogean species at a lower concentration. The hazardous concentration (HC) of unionized ammonia for 5 % of freshwater copepods, obtained by a species sensitivity distribution, was 92 μg l −1 , significantly lower than the HC computed for traditional test species from freshwater environments.

Toward harmonizing ecotoxicity characterization in life cycle impact assessment

“…We evaluated the availability of approaches addressing groundwater organisms in a multimedia modeling context. Several studies indicate that groundwater organisms have longer life cycles due to lower metabolic rates, greater fat storage, and adaptation to low-energy environments (Di Lorenzo et al 2014), and show different sensitivities to chemical exposure (Hose 2005) than phylogenetically related surface-water species, although similar sensitivities have also been indicated (Verweij et al 2015). However, the availability of experimental data for toxicity to groundwater organisms is extremely limited, making it difficult to introduce a separate impact pathway at this point.…”

Metabolic rates of a hypogean and an epigean species of copepod in an alluvial aquifer

“…Two different and highly localised species were identified: the stygoxene E. serrulatus occurring in the well W1 and the stygobiotic D. belgicus occurring in the well W2. DNA barcoding analysis was carried out on live specimens of the two species to exclude the presence of cryptic species belonging to the same genera (see also Di Lorenzo et al, 2014a).…”

Effect of Temperature Rising on the Stygobitic Crustacean Species Diacyclops belgicus: Does Global Warming Affect Groundwater Populations?

“…The scarcity of available data and the difficulty in performing experiments with stygobitic species have frequently led to the sensitivity of groundwater taxa to environmental stressors being inferred from data obtained for epigean relatives. This approach has resulted in the assessment of threshold values for groundwater ecosystem quality that are not protective of the biota which live in this environment [14,45,46]. There are severe constraints that make difficult to perform metabolic, physiological and ecotoxicological studies with groundwater microcrustaceans in laboratory, most of them related to the low metabolism of these species.…”