Agricultural contaminants in amphibian breeding ponds: Occurrence, risk and correlation with agricultural land use

Pollution offsets the rapid evolution of increased heat tolerance in a natural population

Despite the increasing evidence for rapid thermal evolution in natural populations, evolutionary rescue under global warming may be constrained by the presence of other stressors. Highly relevant in our polluted planet, is the largely ignored evolutionary trade-off between heat tolerance and tolerance to pollutants. By using two subpopulations (separated 40 years in time) from a resurrected natural population of the water flea Daphnia magna that experienced a threefold increase in heat wave frequency during this period, we tested whether rapid evolution of heat tolerance resulted in reduced tolerance to the widespread metal zinc and whether this would affect heat tolerance upon exposure to the pollutant. Our results revealed rapid evolution of increased heat tolerance in the recent subpopulation. Notably, the sensitivity to the metal tended to be stronger (reduction in net energy budget) or was only present (reductions in heat tolerance and in sugar content) in the recent subpopulation. As a result, the rapidly evolved higher heat tolerance of the recent subpopulation was fully offset when exposed to zinc. Our results highlight that the many reports of evolutionary rescue to global change stressors may give a too optimistic view as our warming planet is polluted by metals and other pollutants.

Concentration-dependent effects of spinetoram on nontarget freshwater microalgae: A comparative study on Chlorella vulgaris and Microcystis aeruginosa

The rising global demand for agricultural products is leading to the widespread application of pesticides, such as spinetoram, resulting in environmental pollution and ecotoxicity to nontarget organisms in aquatic ecosystems. This research focused on assessing the toxicity of spinetoram at various concentrations (0, 0.01, 0.1, 0.5, 1.0, and 3.0 mg L-1) on two common freshwater microalgae, Chlorella vulgaris and Microcystis aeruginosa, to shed light on the ecotoxicological effects of insecticides. Our findings demonstrate that M. aeruginosa is more sensitive to spinetoram than is C. vulgaris, with a concentration-dependent reduction in the growth rate observed for M. aeruginosa, whereas only the highest concentration of spinetoram adversely affected C. vulgaris. At a concentration of 0.01 mg L-1, the growth rate of M. aeruginosa unexpectedly increased beginning on day 7, indicating a potential hormetic effect. Although initial exposure to spinetoram improved the photosynthetic efficiency of both microalgae strains at all concentrations, detrimental effects became apparent at higher concentrations and with prolonged exposure. The photosynthetic efficiency of C. vulgaris recovered, in contrast to that of M. aeruginosa, which exhibited limited recovery. Spinetoram more significantly inhibited the effective quantum yield of PSII (EQY) in M. aeruginosa than in C. vulgaris. Although spinetoram is not designed to target phytoplankton, its toxicity can disrupt primary productivity and modify phytoplankton-consumer interactions via bottom-up control mechanisms. This study enhances our understanding of spinetoram's ecotoxicity and potential effects on aquatic ecosystems.

Narrative of hazardous chemicals in water: Its potential removal approach and health effects

H₂O is essential for life to exist on earth; it is important to guarantee both the quality and supply of water to satisfy world demand. However, it became contaminated by a number of hazardous, inorganic industrial pollutants, which caused a number of issues like irrigation activities and unsafe human ingestion. Long-term exposure to harmful substances can result in respiratory, immunological, and neurological illnesses, cancer, and problems during pregnancy. Therefore, removing hazardous substances from wastewater and natural water sources is crucial. It is necessary to develop an alternate method that can effectively remove these toxins from water bodies, as conventional methods have several drawbacks. This review primarily aims to achieve the following goals: 1) to discuss the distribution of harmful chemicals: 2) to give specifics on numerous possible strategies for getting rid of hazardous chemicals, and 3) its effects on the environment and consequences for human health have been examined.

Biodegradation characteristics and mechanism of terbuthylazine by the newly isolated Agrobacterium rhizogenes strain AT13

Terbuthylazine (TBA) is an emerging environmental contaminant that poses moderate to high risk to non-target organisms. In this study, a newly TBA-degrading strain, Agrobacterium rhizogenes AT13, was isolated. This bacterium degraded 98.7% of TBA (100 mg/L) within 39 h. Based on the six detected metabolites, three novel pathways of strain AT13, including dealkylation, deamination-hydroxylation, and ring-opening reactions, were proposed. The risk assessment demonstrated that most degradation products might be substantially less harmful than TBA. Whole-genome sequencing and RT-qPCR analysis revealed that ttzA, which encodes S-adenosylhomocysteine deaminase (TtzA), is closely related to TBA degradation in AT13. Recombinant TtzA showed 75.3% degradation of 50 mg/L of TBA within 13 h and presented a K_m value of 0.299 mmol/L and a V_max value of 0.041 mmol/L/min. The molecular docking results indicated that the binding energy of TtzA to TBA was -32.9 kcal/mol and TtzA residue ASP161 formed two hydrogen bonds with TBA at distances of 2.23 and 1.80 Å. Moreover, AT13 efficiently degraded TBA in water and soil. Overall, this study provides a foundation for the characterization and mechanism of TBA biodegradation and may enhance our understanding of the TBA biodegradation by microbes.

Widespread triazole pesticide use affects infection dynamics of a global amphibian pathogen

The sixth mass extinction is a consequence of complex interplay between multiple stressors with negative impact on biodiversity. We here examine the interaction between two globally widespread anthropogenic drivers of amphibian declines: the fungal disease chytridiomycosis and antifungal use in agriculture. Field monitoring of 26 amphibian ponds in an agricultural landscape shows widespread occurrence of triazole fungicides in the water column throughout the amphibian breeding season, together with a negative correlation between early season application of epoxiconazole and the prevalence of chytrid infections in aquatic newts. While triazole concentrations in the ponds remained below those that inhibit growth of Batrachochytrium dendrobatidis, they bioaccumulated in the newts' skin up to tenfold, resulting in cutaneous growth-suppressing concentrations. As such, a concentration of epoxiconazole, 10 times below that needed to inhibit fungal growth, prevented chytrid infection in anuran tadpoles. The widespread presence of triazoles may thus alter chytrid dynamics in agricultural landscapes.

Contributions of water-borne corticosterone as one non-invasive biomarker in assessing nitrate pollution stress in tadpoles of Rana temporaria

Among a multitude of stressors to which wildlife is exposed, environmental pollution is a pervasive one that poses a serious threat. The permeable skin of amphibians is likely to increase direct contact of the body with pollutants, making them a group worth studying to access environmental quality. Consequently, finding reliable and complementary biomarkers that will present detectable and predictable changes in response to pollutants is essential to identify pollution sublethal effects on amphibians and to investigate whether these are in part responsible for population declines. The glucocorticoid hormone corticosterone (CORT), involved in many metabolic functions, is often used to measure the physiological stress response to environmental stressors in amphibians. In this study, we evaluated whether water-borne CORT can serve as a non-invasive biomarker for nitrate pollution stress in the European common frog (Rana temporaria) by comparing the effect of nitrate exposure on hormone release rates and on other physiological downstream biomarkers, i.e., ultimate physiological effects of the stressor. Specifically, we investigated the effect of different nitrate concentrations (0, 10, 50, and 100 mg/L) on water-borne CORT release rates, age, size, and body condition. Exposure to nitrate pollution significantly increased age at metamorphosis and water-borne CORT release rates, and led to reduced mass and body condition, but only at higher nitrate concentrations (i.e., 50 and 100 mg/L). Considering this similar sensitivity to other acknowledged biomarkers, water-borne CORT was a reliable biomarker of physiological stress in R. temporaria exposed to nitrate pollution stress in a controlled single-stressor laboratory approach. Thus, water-borne CORT is a promising method to be included in more holistic approaches. We recommend that such approaches keep testing multiple biomarker combinations, as species are exposed to several stressors likely to interact and produce varied outcomes in different biomarkers in their natural habitats.

Dynamics of microbial communities during biotransformation of nitrofurantoin

The purpose of this research was to investigate the biodegradation of nitrofurantoin (NFT), a typical nitrofuran antibiotic of potential carcinogenic properties, by two microbial communities derived from distinct environmental niches - mountain stream (NW) and seaport water (SS). The collected environmental samples represent the reserve of the protected area with no human intervention and the contaminated area that concentrates intense human activities. The structure, composition, and diversity of the communities were analyzed at three timepoints during NFT biodegradation. Comamonadaceae (43.2%) and Pseudomonadaceae (19.6%) were the most abundant families in the initial NW sample. The top families in the initial SS sample included Aeromonadaceae (31.4%) and Vibrionaceae (25.3%). The proportion of the most abundant families in both consortia was remarkably reduced in all samples treated with NFT. The biodiversity significantly increased in both consortia treated with NFT suggesting that NFT significantly alters community structure in the aquatic systems. In this study, NFT removal efficiency and transformation products were also studied. The biodegradation rate decreased with the increasing initial NFT concentration. Biodegradation followed similar pathways for both consortia and led to the formation of transformation products: 1-aminohydantoin, semicarbazide (SEM), and hydrazine (HYD). SEM and HYD were detected for the first time as NFT biotransformation products. This study demonstrates that the structure of the microbial community may be directly correlated with the presence of NFT. Enchanced biodiversity of the microbial community does not have to be correlated with increase in functional capacity, such as the ability to biodegradation because higher biodiversity corresponded to lower biodegradation. Our findings provide new insights into the effect of NFT contamination on aquatic microbiomes. The study also increases our understanding of the environmental impact of nitrofuran residues and their biodegradation.

Almalki A, F Alkhanani M, Pal DB. Waste seeds of Mangifera indica, Artocarpus heterophyllus, and Schizizium commune as biochar for heavy metal removal from simulated wastewater

The threat of arsenic contamination in water is a challenging issue worldwide. Millions of people utilize untreated groundwater having high levels of arsenic in developing countries. Design Expert 6.0.8 has been used to design experiments and carried out statistical analysis for optimization of different parameters. It is of prime importance to develop cheap environment friendly bio-sorbent for protecting health of the poor from ill effects of arsenic. In the present investigation, we prepared bio-sorbent from the solid waste seed biomass of Mangifera indica (M), Artocarpus heterophyllus (JF), and Schizizium commune (JP). The characterization of bio-sorbents has been done by using different techniques namely FTIR and XRD. Arsenic concentration was estimated using ICP and adsorption parameters optimized for pH, adsorbent dose, and initial arsenic concentration. At pH 8.4, kinetics study of arsenic removal was M (94%), JF (93%), and JP (92%) for initial concentration of 2.5 ppm. The adsorption kinetics was well explained by Freundlich model and pseudo-second reaction order.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13399-021-02078-5.