The demand for lanthanides (LN) has seen a steady increase and is anticipated to continue to grow. Due to their unique properties, they have become essential in key components of new technologies, such as batteries, wind turbines, electronic components and other devices needed to facilitate energy transition away from fossil fuels. These elements are also increasingly used in a range of new technologies, including medical applications and telecommunication. In this context, the concentrations of lanthanides are expected to increase in freshwater environments (Gwenzi et al., 2018). Our limited knowledge about the risk that they pose to organisms limits our ability to develop guidelines for environmental protection. Research on this issue has so far been hindered by the peculiar properties of lanthanides, that tend to form insoluble precipitates when added in standard ecotoxicological test media (Blinova et al., 2018). This and other challenges of studying lanthanide toxicity were addressed in this in-depth study that leaves few stones unturned. 

The study by Vignati and colleagues (2024) is the first to investigate the acute toxicity of all LN, with the exception of promethium, a radioactive element, on Daphnia magna, a model test species, following the ISO 6341 (2012) norm. The authors designed their study to generate data useable for the development of risk assessment guidelines for the LN series and to generate data-based recommendations for future studies on LN ecotoxicity. They exposed daphnids to nine to ten dilutions of all tested LN in a medium and carried out 48-hour acute immobilization assays. Initial and final pH was measured along with concentrations of LN in the test solutions sampled at various intervals by ICP-MS. This data allowed calculation of LN speciation, performed using VisualMinteq software. Effect concentrations were also calculated using different metrics based on initial (nominal), time-averaged or modelled LN3+ exposure concentrations.

In their multi-faceted investigation, the authors reported several observations that clearly contribute to a better understanding of the ecotoxicity of LN to aquatic organisms and provide useful advice for future studies, briefly summarized here. Proper characterization of exposure concentrations is a key in any ecotoxicological study. Their project shows that even for a short, 48 h exposure, LN concentrations decrease due to a combination of precipitation and, possibly, adsorption. The concentration decrease was inversely proportional to the LN atomic mass, which may reduce the analytical requirements for future studies using the same test medium. The addition of LN to the test medium also modified pH and a detailed hypothesis is formulated to explain this phenomenon that has implications for ecotoxicological endpoints. Conclusions on LN ecotoxicity drawn in this study are based on experimental data and on extensive thermodynamic speciation modeling. The values of EC50 presented in the study varied by several order of magnitude depending on the chosen exposure metric, underscoring the urgent need for consensus-building on this issue across the research community. The authors also provide a comparison of their conclusions on EC50 values for daphnids with the limited data available in the literature, further validating their data with cautions carefully laid out about experimental design. The paper concludes with a list of seven caveats that should be considered both for regulators who will want to use the data presented in the paper for environmental LN concentrations regulations and for future studies. These caveats highlight the importance of considering LN speciation and chemical behavior during ecotoxicity assays, their influence on exposure concentrations, and their importance for risk assessment. They also reiterate that since LN concentrations in filtered water collected in the field are not directly comparable to EC50 values derived from laboratory studies using total or free LN3+ concentrations, an effort must be made to harmonize the methods of LN concentration measurements in field and laboratory studies. Overall, this paper may be one of the most rigorous studies in the current literature about LN ecotoxicity in freshwater systems. In its approach, it sets a precedent for future studies aiming at generating EC50 values or other toxicological endpoints of inorganic contaminants. The paper, carefully reviewed by Carrie Rickwood and by an anonymous reviewer, is a major contribution towards our understanding of LN ecotoxicity.
 
References
Blinova, I., Lukjanova, A., Muna, M., Vija, H., & Kahru, A. (2018). Evaluation of the potential hazard of lanthanides to freshwater microcrustaceans. Sci. Tot. Environ. 642 :1100-1107. https://doi.org/10.1016/j.scitotenv.2018.06.155

Gwenzi, W., Mangori, L.,  Danha, C., Chaukura, N, Dunjana, N., Sanganyado, E. (2018). Sources, behaviour, and environmental and human health risks of high technology rare earth elements as emerging contaminants. Sci. Total Environ., 636:299-313. https://doi.org/10.1016/j.scitotenv.2018.04.235

ISO. (2012). Water quality — Determination of the inhibition of the mobility of Daphnia magna Straus (Cladocera, Crustacea) — Acute toxicity test (norm 6341). https://www.iso.org/standard/54614.html

Vignati, D.A.L., Martin, L.A., Poirier, L., Zalouk-Vergnoux, A., Fouque, C., Clément, B., Hissler, C., Cossu-Leguille, C. (2024). Ecotoxicity of lanthanides to Daphnia magna: insights from elemental behavior and speciation in a standardized test medium. Ver.3 peer-reviewed and recommended by Peer Community In Ecotoxicology and Environmental Chemistry. https://hal.science/LIEC-UL/hal-04302491v3

Soil microbial communities play a crucial role in maintaining ecosystem health, driving key processes such as nutrient cycling, organic matter decomposition, and soil fertility. However, these microbial populations are highly sensitive to environmental changes and chemical stressors, including pesticides. The preprint "Evaluating the effects of environmental disturbances and pesticide mixtures on soil microbial endpoints," provides valuable insights into how soil microbial communities respond to environmental fluctuations and pesticide exposure (Drocco et al., 2025). By integrating experimental soil microcosms with targeted microbial assessments, the study offers a comprehensive view of the resilience and vulnerability of soil microbiota under multiple stress conditions.

The study aimed to assess how temperature and humidity fluctuations, along with pesticide exposure, impact soil microbial communities. A total of 250 soil microcosms were subjected to three different environmental conditions: heat disturbance, high humidity simulating heavy rain, or a control with no disturbance. Following a three-day recovery period, the microcosms were exposed to different pesticide active ingredients—clopyralid (herbicide), cypermethrin (insecticide), and pyraclostrobin (fungicide)—either individually or in combination at standard (1x) and elevated (10x) agronomic doses.

By evaluating microbial endpoints related to diversity and community structure, the researchers were able to determine how environmental disturbances and chemical exposure influence soil microbial functions (Bacmaga et al., 2015). Of particular interest was the focus on microbial guilds involved in nitrification, a critical process for soil nitrogen cycling and agricultural productivity (Dominati et al., 2010).

The study’s findings reveal a complex interplay between environmental stressors and pesticide exposure on microbial communities. Some key observations showed that heat and high humidity significantly altered microbial diversity and composition before pesticide application. This suggests that climate-driven disturbances can precondition microbial communities, potentially influencing their subsequent responses to chemical exposure. Moreover, the pesticide effects depend on dose and combination, while individual pesticides had measurable impacts on microbial endpoints, their effects were amplified when applied in mixtures or at elevated doses. This underscores the importance of considering real-world pesticide applications, where mixtures are commonly used. Furthermore, the results indicate that the microbial guilds involved in nitrification appeared to be disproportionately affected by pesticide exposure, raising concerns about long-term soil fertility and nitrogen availability in treated soils.

These findings have significant implications for sustainable agriculture and soil health management. Understanding how soil microbiota respond to environmental and chemical stressors can inform strategies to mitigate negative impacts, such as adopting precision agriculture techniques, improving pesticide formulations, and implementing soil conservation practices.

Despite its valuable contributions, the study has some limitations. The controlled microcosm approach, while useful for isolating specific variables, may not fully capture the complexity of field conditions. Long-term effects of pesticide exposure were also not assessed, leaving questions about microbial recovery and ecosystem stability over extended periods. Future research should focus on field-based experiments and long-term monitoring to validate and expand on these findings.

In conclusion, the current study highlights the intricate interactions between environmental stressors and pesticide exposure on soil microbial communities. By leveraging a robust experimental design and providing open-access data and statistical scripts, the research enhances our understanding of soil microbial dynamics and their implications for agricultural sustainability. As climate change and intensive pesticide use continue to shape soil ecosystems, such studies are essential for developing resilient and sustainable soil management practices.

References

Bacmaga, M., et al., 2015. Microbial and enzymatic activity of soil contaminated with a mixture of diflufenican + mesosulfuron-methyl + iodosulfuron-methyl-sodium. Environ Sci Pollut Res Int. 22: 643-56, https://doi.org/10.1007/s11356-014-3395-5 

Dominati, E., et al., 2010. A framework for classifying and quantifying the natural capital and ecosystem services of soils. Ecological Economics. 69: 1858-1868, https://doi.org/10.1016/j.ecolecon.2010.05.002 

Drocco, C., Coors, A., Devers-Lamrani, M., Martin-Laurent, F., Rouard, N., Spor A. 2025. Evaluating the Effects of Environmental Disturbances and Pesticide Mixtures on N-cycle related Soil Microbial Endpoints. ver.3 peer-reviewed and recommended by PCI Ecotoxicology and Environmental Chemistry, https://doi.org/10.1101/2024.01.22.576671

Pesticides give rise to considerable concern due to their impact on biodiversity. Amongst the vast range of compounds used as herbicides, glyphosate (GLY) is the most widely applied one at global scale and its transformation product, aminomethylphosphonic acid (AMPA) is also ubiquitous. However, the toxicity of these chemicals on non-target organisms, including mammals, is somewhat overlooked (Kissane et al., 2017). Beside these two chemicals, Fritsch et al. (2024) also considered another organophosphorus herbicide, i.e. glufosinate (GLUF). Their study examined exposure levels in rodents and shrews living in contrasted cropped and semi-natural habitats in France – i.e., conventional farmland, organic fields, and hedgerows – through the analysis of herbicide residues in their hair. The hypothesis that herbicide residues in hair reflect the exposure to multiple pesticides in wildlife is supported by several papers (i.e. Krief et al. 2017; Fritsch et al. 2022).

Results obtained by Fritsch et al. (2024) indicated that the target compounds were widespread in the investigated environments, i.e. GLY, AMPA, and GLUF were detected in 64%, 51%, and 44% of samples, respectively. Diet appeared as a major driver of contamination, as herbivorous and omnivorous voles exhibited higher contamination levels than insectivorous or omnivorous species such as shrews and wild mice. In addition, habitat was also a significant factor: GLY concentrations were particularly high in individuals collected from hedgerows, surpassing those found in crop fields. This unexpected result highlights the contamination of areas considered as ecological refuges for the investigated species. Exposure levels did not show clear differences across sites, based on farming practices or pesticide application intensity.

In addition, the measured concentrations of GLY (median 2.7 pg/mg), AMPA (median 1.4 pg/mg), and GLUF (median 3.5 pg/mg) frequently reached thresholds associated with toxic effects on small mammals. In worst case scenarios, exceedance percentages attained values as high as 94 %.

Altogether, these results definitely raise concerns about the potential impact of GLY, AMPA and GLUF on non-target wildlife species and populations. These findings by Fritsch et al. (2024) therefore emphasize the widespread presence of these chemicals in agricultural landscapes and question the safety of herbicide use, even in habitats meant to protect biodiversity. This study underscores the need for more comprehensive evaluation of the ecological effects of herbicides to guide policy and conservation efforts.

References

Kissane Z, Shephard JM (2017) The rise of glyphosate and new opportunities for biosentinel early-1068 warning studies. Conservation Biology 31: 1293–1300; https://doi.org/10.1111/cobi.12955

Krief S, Berny P, Gumisiriza F, Gross R, Demeneix B, Fini JB, et al. (2017) Agricultural expansion as risk to endangered wildlife: Pesticide exposure in wild chimpanzees and baboons displaying facial dysplasia. Science of the Total Environment 598:647–656; 1072; https://doi.org/10.1016/j.scitotenv.2017.04.113

Fritsch C, Appenzeller BM, Burkart L, Coeurdassier M, Scheifler R, Raoul F, et al. (2022) Pervasive exposure 1041 of wild small mammals to legacy and currently used pesticide mixtures in arable landscapes. 1042 Sci Rep 12:15904; https://doi.org/10.1038/s41598-022-19959-y

Fritsch C, Appenzeller BM, Bertrand C, Coeurdassier M, Driget V, Hardy EM, Palazzi P, et al. (2024) Exposure of wild mammals to glyphosate, AMPA, and glufosinate: a case for “emerging organic contaminants”?. HAL, ver.3 peer-reviewed and recommended by PCI Ecotoxicology and Environmental Chemistry https://hal.science/hal-04485797