Ecotoxicology最新文献

Microplastics (MPs) are ubiquitous pollutants in freshwater environments. In this study, freshwater mussels, Unio delicatus, were exposed to both environmental MPs (e-MP) and commercial MPs (c-MP) that include green fluorescent MP (gf-MP), polyethylene (c-PE) and polystyrene (c-PS) at environmental concentrations (5 mg/L and 50 mg/L) over duration of 7 and 30 days. According to in vivo experiment results, both e-MPs and c-MPs induced significant changes in the total hemocyte counts of mussels (p < 0.05). Exposure to high concentrations of e-MPs and c-MPs for 7 days led to decreased cellular glutathione levels in the mussels, while exposure to low concentrations of e-MPs and c-PS for 7 days resulted in increased advanced oxidation protein products (AOPP). Mussels exposed to high concentrations of e-MPs for 30 days exhibited decreases in both glutathione levels and AOPP values. Although no damage was observed in tissues other than gills and digestive gland, histopathological alterations were observed in these tissues following exposure to 50 mg/L c-MPs. Additionally, MPs were observed in the intestine tissues. In vitro experiments using the MTT assay showed no significant difference in cell viability between the MP-exposed group and the control group at tested concentrations, with no observed dose-response relationship (p > 0.05). Nevertheless, certain cells exhibited signs of cell death, such as disrupted cellular structures, condensed nuclei, and loss of cellular integrity. These observations were consistent with mechanical compression, indicating that physical contact with MPs may result in cell damage or death. These findings demonstrate that environmentally relevant concentrations of MPs have toxic effects on freshwater mussels and multiple parameters provide valuable insight for the evaluation of health risks of organisms.

Understanding the lethal and sublethal impacts of pesticides on biocontrol agents is crucial for the successful implementation of integrated pest management (IPM) programs. This study investigated the sublethal effects of fenpyroximate, a broad-spectrum acaricide/insecticide, on the fitness of Scolothrips longicornis Priesner (Thysanoptera: Thripidae), a key predator of the two-spotted spider mite, in controlled laboratory environments. Adult predators were exposed to pesticide residues on leaf discs to estimate parameters of concentration-mortality response models for females and males and calculate median lethal concentration (LC₅₀) as well as sublethal concentrations (LC₁₀, LC₂₀ and LC₃₀) used in subsequent bioassays. The estimated LC₅₀ values for female and male predators were 18.32 and 15.49 µg a.i./mL, respectively. Results of sublethal concentrations experiments did not reveal any significant impact on the development of each stage or the survival rate of S. longicornis juveniles compared to those in the control group. However, the longevity of adult males and females was significantly lower at all sublethal concentrations than in the control. Moreover, the fecundity decreased significantly at all sublethal concentration treatments. With one exception (LC₁₀), both the adult preoviposition period and total preoviposition period increased with increasing sublethal concentrations compared to those of the control. The shortest oviposition period (9.30 days) was observed at the LC₃₀. For the life table parameters of S. longicornis females treated with sublethal concentrations, a significant decrease was found in the intrinsic rate of increase, net reproductive rate and finite rate of increase, whereas the mean generation time in the LC₁₀ treatment was lower than that in the other treatments. This underscores the imperative need to consider sublethal concentration effects of fenpyroximate in the strategic design and implementation of IPM systems.

The widespread application of plastics and its eventual degradation to micro-sized or nano-sized plastics has led to several environmental concerns. Moreover, nanoplastics can easily cascade through the food chain accumulating in the aquatic organisms. Thus, our study focussed on investigating the hazardous impact of nano-sized plastics on aquatic species including Nitrobacter vulgaris, Scenedesmus sp, and Daphnia magna. Various concentrations of polystyrene nanoplastics ranging from 0.01 mg/L to 100 mg/L were tested against Nitrobacter vulgaris, Scenedesmus sp, and Daphnia magna. The minimum inhibitory concentration of polystyrene nanoplastics in Nitrobacter vulgaris was found to be 25 mg/L, and in Daphnia magna, the median lethal concentration 50 was observed to be 64.02 mg/L. Exposure of Scenedesmus sp with increasing nanoplastic concentrations showed a significant decrease in total protein (p < 0.001), and chlorophyll content (p < 0.01), whereas the lipid peroxidation increased (p < 0.001) significantly. Similarly, Nitrobacter vulgaris and Daphnia magna showed a significant decrease in catalase activity (p < 0.001) and an increase in lipid peroxidation levels (p < 0.01). Concomitant with lipid peroxidation results, decreased superoxide dismutase levels (p < 0.01) and protein concentrations (p < 0.01) were observed in Daphnia magna. Besides, the increasing concentration of polystyrene nanoplastics displayed an elevated mortality rate in Scenedesmus sp (p < 0.001) and Nitrobacter vulgaris (p < 0.01). Further, scanning electron microscopy analysis substantiated the morphological alterations in Nitrobacter vulgaris and Scenedesmus sp on exposure to polystyrene nanoplastics.

A significant limitation of behavioral ecotoxicology is the challenge of obtaining reproducible results due to a wide range of testing conditions. In particular, shoal size affects almost all aspects of fish behavior, but is rarely considered as a factor in ecotoxicological studies. In the present study, we compared the swimming and antipredator responses of different sized shoals of Arabian killifish (Aphaniops stoliczkanus) after exposure to environmentally realistic concentrations of the antidepressant medication sertraline. Groups of fish (1, 3 or 5 individuals) were exposed to either 5 or 50 ng/L sertraline. After 37 days, swimming behavior and responses to a predator alarm were measured. We found that the effects of group size were much stronger than the effects of sertraline on swimming. Group size was also the major factor influencing responses to the predator alarm, with single fish showing the strongest responses. Sertraline directly affected acceleration, turning speed and average distance to the arena wall. For all three parameters, there were significant interactions with shoal size, demonstrating that responses differed depending on the size of the group. We also found that effects of sertraline could still be observed 14 days after cessation of exposure. The study highlights the importance of considering social context and specifically shoal size when designing behavioral studies on chemicals. Failure to consider this may result in over- or under-estimation of risks.

Triclosan (TCS) is a lipophilic, broad spectrum antimicrobial agent commonly used in personal care products with a projected continuous escalation in aquatic environments in the post COVID 19 era. There is rich documentation in the literature on the alteration of physiological responses in fish due to TCS exposure; however, studies on gut associated bacteria of fish are still scarce. This is the first attempt to determine changes in bacterial community structure due to exposure of TCS on Labeo rohita, a commercially essential freshwater species, using 16S V3-V4 region ribosomal RNA (rRNA) next-generation sequencing (NGS). Chronic exposure of TCS at environmentally realistic concentrations viz. 1/5th (T₁: 0.129 mg/L) and 1/10th (T₂: 0.065 mg/L) of LC₅₀ for 28 days resulted in the dose dependent bioconcentration of TCS in the fish gut. Prolonged exposure to TCS leads to disruption of gut bacteria evidenced by down regulation of the host immune system. Additionally, high-throughput sequencing analysis showed alternation in the abundance and diversity of microbial communities in the gut, signifying Proteobacteria and Verrucomicrobia as dominant phyla. Significant changes were also observed in the relative abundance of Chloroflexi and Gammatimonadetes phyla in TCS exposed groups. The study revealed that gut microbiome can be used as a biomarker in assessing the degree of TCS toxicity in commercially important fish species.

Air pollutants, specifically, Sulphur Dioxide (SO₂) and Nitrogen Dioxide (NO₂) cause numerous biochemical changes in plants; by studying the biochemical parameters, plant resistance against these pollutants can be evaluated. The effect of air pollutants on biochemical parameters such as ascorbic acid (AA), total chlorophyll (TC), pH and the relative water content (RWC) of leaves has been investigated in the present study. The objective of the present study was to observe the relationship between biochemical parameters of plants and ambient air pollutants (SO₂ and NO₂). The morphological and biochemical changes of the sampled leaves of different plants were studied. Simultaneously, ambient air quality data was collected from the central pollution control board (CPCB) online portal. Among the sampled plants, Ficus religiosa and Morus alba plant species can be recommended as tolerant for the sampling sites: Jalandhar, Amritsar, and Ludhiana. Ficus benghalensis and Ficus religiosa can be recommended as tolerant for Chandigarh sector 25 and 53 respectively. As a result, it has been observed that SO₂ has a negative effect on the relative water content and ascorbic acid content of most plant species, while NO₂ can have ambiguous effect on plants (toxic and beneficial), and no strong association has been found with biochemical parameters. The current study provides pollutant-specific information and insights into the variations caused by air pollutants. The present study will contribute in suggesting the tolerant plant species that could provide new approaches for developing urban landscapes.

The yellow fever mosquito, Aedes aegypti L., known for transmitting viruses causing yellow fever, dengue, chikungunya, and Zika fever, presents a substantial risk to global human health. The development of insecticide resistance in disease vectors has become a significant problem in Ae. aegypti. Monitoring insecticide resistance is essential for resistance management in Ae. aegypti. This study involved the collection of Ae. aegypti populations from four important cotton-growing regions in southern Punjab, Pakistan, for resistance monitoring over a two-year period (2021-2022). This study also assessed the impact of insecticide resistance on biological parameters of Ae. aegypti. Moderate-to-high levels of resistance were observed against all the tested insecticides viz., chlorpyrifos, chlorfenapyr, deltamethrin, flonicamid, spirotetramat, and spinetoram. However, compared to the Lab-susceptible population, higher levels of resistance to buprofezin (59.03-84.40) and imidacloprid (68.49-100.01) were found in all populations. This high resistance can be attributed to increased use of these two insecticides in cotton fields, as compared to other insecticides. In the lab-susceptible population, higher values for the intrinsic rate of increase (r) and the net reproductive rate (R₀) i.e., 0.20 per day and 23.24 offspring/female were observed, respectively. This was also validated by population projection data where more than 2.5-fold adults (1,020,361.80 individuals) were calculated in the Lab-susceptible population as compared to the most resistant populations. Sublethal exposure to insecticides may induce physiological or biochemical changes in organisms, subsequently influencing the biological traits. Resistance monitoring provides essential guidance before launching a successful chemical-based vector management program.

Mussels are filter-feeding animals with a sedentary lifestyle and thus, they were accepted as good bioindicator animals to investigate environmental pollution. In this study, freshwater mussels (Unio tigridis) were exposed to cadmium (0, 30, 90, 270 µg Cd/L) for up to 21 days. Then, the responses of several biomarkers belonging to the antioxidant, osmoregulation and nervous systems, as well as the energy reserves of mussels were investigated. The animals were fed on laboratory-cultured algae (Chlorella vulgaris) during the experiments. Data showed that the exposure conditions did not cause mussel mortality within 21 days, though the levels of all biomarkers altered significantly (p < 0.05) compared to controls. Cadmium exposures significantly altered the activities of antioxidant enzymes in the digestive glands. Similarly, malondialdehyde (MDA) levels in the digestive glands significantly increased after cadmium exposures. Likewise, acetylcholinesterase (AChE) activity and Ca-ATPase activity in the muscle significantly decreased. There were decreases in Na-ATPase and increases in Mg-ATPase activities in the gill. The total energy reserves of mussels significantly decreased, especially at the higher cadmium concentrations. This study showed that environmentally relevant cadmium concentrations could alter the levels of biomarkers belonging to different metabolic systems, emphasizing their possible usage in evaluating metal contamination.

Agricultural insecticide usage presents a complex challenge, particularly when addressing hidden targets such as concealed pest species. Typically, insecticide spraying targets either the host plant or the soil substrate, reaching the target when the pests move or feed, yet their vulnerability when concealed remains low. This study delves into the often-obscure effects of insecticides on hidden herbivore species, focusing specifically on the diamide insecticide chlorantraniliprole and its impact on the concealed insect herbivore, the coffee leaf miner Leucoptera coffeella (Guérin-Mèneville & Perrottet) (Lepidoptera: Lyonetidae). We document the progressive effects of chlorantraniliprole from egg-laying through the insect's development and reproductive output. By examining egg-laying preferences, development, survival, respiration rate, leaf consumption, and polysaccharide and protein accumulation, alongside fecundity, in two field-collected leaf miner populations, we elucidate chlorantraniliprole's broader effects. While the insecticide did not alter the leaf miner's egg-laying preferences, one population exhibited higher larval survival, indicating chlorantraniliprole resistance. This chlorantraniliprole-resistant population displayed a lower respiration rate-indicative of reduced stress-and higher leaf consumption, accompanied by increased sugar and protein accumulation. Although this population showed lower adult longevity, it exhibited higher fecundity. These findings highlight the multifaceted impacts of insecticides, extending beyond survival to affect development, fecundity, and potential fitness. Variations in response among insect populations suggest that resistant insects may outperform susceptible ones even under sublethal exposure, with significant implications for management strategies and future outbreaks.

(1) Background: Ecotoxicological screening evaluates the acute toxicity of WWs. The Vibrio fischeri ecotoxicological assay analyses inlet and outlet wastewater samples from two urban wastewater treatment plants in Catania, Sicily, Italy. (2) Methods: The APAT CNR IRSA 8030 Man 29 method was used as method; (3) Results: The results showed toxicity values below the limit of the Italian Legislative Decree 152/06; (4) Conclusions: This monitoring study allows to verify the efficacy, and the outlet quality of WWs discharged to sea water. This ecotoxicological assay is a valuable tool for evaluating the combined toxicity of various pollutants that underline the total damage of the studied matrices detecting the true effect of complex mixtures on the environment and its fauna.