Ecotoxicology最新文献

Stingless bees are important pollinators in tropical regions, but their survival and behavior have been impacted by various factors, including exposure to insecticides. Here, we evaluated the lethal and sublethal effects of commercial formulations of two widely used insecticides, flupyradifurone (FPF formulation), and cyantraniliprole (CY formulation), on Melipona beecheii and Nannotrigona perilampoides. The study involved oral exposure of bees to insecticides, calculation of the lethal concentration (LC₅₀) and the lethal time (LT₅₀), and evaluation of walking and flight take-off activities. The LC₅₀ values showed that the largest bee, M. beecheii, was more sensitive than N. perilampoides to both insecticides and that the FPF formulation had faster lethal effects in both species (N. perilampoides, 9.6 h; M. beecheii, 5 h) compared to the effects of the CY formulation (N. perilampoides, 17 h; M. beecheii, 24.7 h). Sublethal concentrations (LC_50/10 and LC_50/100) of both insecticides affected walking and flight take-off activities. After 6-24 h of exposure, both FPF and CY formulations significantly reduced the mean walking speed of N. perilampoides (0.962-1.402 cm/s) and M. beecheii (2.026-2.589 cm/s) compared to the control groups (N. perilampoides: 1.648-1.941 cm/s; M. beecheii: 2.759-3.471 cm/s). Additionally, the FPF and the CY formulation impaired individual flight take-off in both species. This study provides the first comprehensive evaluation of the lethal and sublethal effects of flupyradifurone and cyantraniliprole on M. beecheii and N. perilampoides, offering valuable information for future research on insecticide toxicity in stingless bees.

Pharmaceuticals, including non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (IBU) and naproxen (NPX), are widely used for medical purposes but have also become prevalent environmental contaminants. However, there is limited understanding of their effects on aquatic organisms, especially regarding multigenerational and mixture exposures. This study aimed to evaluate the toxicological impacts of ibuprofen and naproxen, individually and in combination, on three generations of Daphnia carinata, a freshwater organism. Daphnids were exposed to environmentally relevant concentrations of ibuprofen and naproxen (0.1, 0.5, 2.5 µg/L and 0.1 + 0.1, 0.1 + 0.5, 2.5 + 2.5 µg/L) throughout multiple generations. The endpoints assessed were reproduction, body size, reproduction recovery, and behaviour. The results revealed that ibuprofen and naproxen negatively impacted reproduction, reducing reproduction output across generations. Additionally, daphnids exhibited changes in body size, with significant alterations observed in the F2 and F3 generations. Male individuals and ephippium were also present at all concentrations throughout all generations. Although reproduction recovery could not be observed in daphnids after one generation in clean water, the average number of neonates was higher in a few treatments in generation F4 compared to generation F3. In addition, binary mixtures of the drugs showed synergistic effects on daphnids' reproduction for most generations. The multigenerational approach provided valuable insights into the long-term effects of these NSAIDs on reproduction success and population dynamics. This study contributes to understanding the ecotoxicity of ibuprofen and naproxen in aquatic organisms, particularly in a multigenerational context and in the presence of mixture exposures.

This study focused on investigating the water quality in the Pirajibú River, a relevant water body that flows through the industrial zone of Sorocaba (São Paulo/Brazil). Due to the limitations of assessing water quality based solely on standard physicochemical tests, an ecotoxicological approach was used to assess biomarker changes in the liver of bullfrog tadpoles (Aquarana catesbeiana). The animals were divided into groups and exposed to water samples collected upstream and downstream of the industrial zone. After 96 h, the upstream group presented a decrease in the enzymatic activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD) and an increase in the activity of catalase (CAT). For the downstream group, while a decreased activity was observed for SOD, an increase in CAT and glutathione S-transferase (GST) activities was noted. A decrease in lipid peroxidation (LPO) levels was observed in the downstream group, and increased carbonyl protein (PCO) levels in the upstream and downstream groups. Integrated Biomarker Response (IBR) revealed GSH and PCO as the most responsive biomarkers, despite the lack of differences noted between the groups. Regardless of whether the water quality standards of Pirajibú River were following Brazilian environmental legislation, the tadpoles presented high sensitivity when exposed to the water, even for a short period.

Many shorebird populations are declining, and contaminants may be partly contributing to the decline by interfering with feeding, migration, and breeding success. The goal of our study was to determine whether there was a temporal change in concentrations of trace elements of red knot (Calidris canutus rufa), sanderling (Calidris alba), and ruddy turnstone (Arenaria interpres) during spring migration in Delaware Bay, New Jersey, USA. We sampled blood to 1) determine levels of trace elements in 2019, 2) compare 2019 trace element levels with those from shorebirds in 2011-2012, and 3) examine variability in blood levels of trace elements among species. In 2019: 1) trace element levels were significantly different among species (except cadmium[Cd]), 2) Cd was lowest in all species, and arsenic (As) and selenium (Se) were highest, and 3) sanderlings had the highest levels of As and Se, and knots had the highest levels of chromium (Cr) and lead (Pb). Se was higher in these shorebirds than reported for other shorebirds from elsewhere. As, mercury (Hg), and Se increased significantly between 2011-2012 and 2019 in all three species. There were no significant temporal changes in Cd. Chromium (Cr) decreased in knots and sanderling. The temporal increases in As, Se, and Hg bear watching as they are toxic in vertebrates, and each can decrease the toxicity of the others. The data indicate that shorebirds can be bioindicators of changing trace element levels in estuaries, potentially providing early warning of increasing levels of As, Hg, and Se in the environment.

The toxic additives that leach from tire wear particles (TWPs) cause mass die-offs in fish and impact zooplankton as secondary consumers in the aquatic food web. In addition to the direct impacts of TWP leachate on a single generation, there may be potential delayed carryover effects across multiple generations from parental exposure, which may amplify the adverse effects of the leachate on individual reproduction and, consequently, on the entire population. In this study, the single, multiple, and transgenerational effects of TWP leachate at various concentrations on the reproduction and lifespan of the rotifer Brachionus calyciflorus were investigated. The results indicated that the lifespan and reproductive output of rotifers exposed to TWP leachate (0-1500 mg/L) decreased as the concentration increased above 250 mg/L. There was a clear multigenerational effect of TWP leachate on rotifer reproduction. The inhibition rates were consistently greater at 500 mg/L than at 250 mg/L leachate. Although the reproduction of rotifers exposed to 250 mg/L TWP leachate increased in the first two generations (P and F1), it was inhibited in subsequent generations. The inhibitory effect of 500 mg/L TWP leachate persisted across all generations, leading to population extinction by the F4 generation. A significant transgenerational effect of TWP leachate was found on reproduction. The adverse impact of exposure to 250 mg/L leachate for fewer than three generations could be reversed when offspring were transferred to clean media. However, this recovery was not observed after continuous exposure for more than four generations. Exposure to high-dose TWP leachate also caused irreversible damage to reproduction. Therefore, TWP leachate can result in cascading toxicity on zooplankton populations through carryover and cumulative effects on reproduction.

Hydroelectric plants impact the dynamics of mercury accumulation and transfer to aquatic ecosystems and organisms. This study aimed to determine total mercury (THg) concentration in filtered water, aquatic macrophytes, and fish and assess the influence of fluvial regime (low-water, rising-water, and high-water) and the feeding habits of fish species caught upstream and downstream of the Curuá-Una hydroelectric dam in the Brazilian Amazon. THg levels were determined by cold-vapor atomic fluorescence spectrometry. THg concentration in filtered water was higher (5.3-11.2 ng L^-1) during the low-water period. THg concentration in fish ranged from 0.075 to 1.160 µg g^-1 in specimens caught downstream and from 0.014 to 1.036 µg g^-1 in specimens caught upstream of the dam. The highest THg concentrations were detected in specimens of the piscivorous species Acestrorhynchus falcirostris (1.161 µg g^-1) caught at downstream sites. There were significant correlations of THg concentration with the trophic level (Analysis of Variance; p ≤ 0.001) of fish species and fluvial regime (Analysis of Variance; p ≤ 0.001). The macrophyte Utricularia foliosa contained the highest THg levels in leaf tissues in the low-water period (71.4 µg g^-1). It is concluded that THg concentration varies between fish trophic levels and fluvial regimes. Macrophytes contribute to enhancing mercury transfer and availability along the aquatic trophic chain.

The study provides a descriptive understanding of the toxic effect of heavy metal chromium on the hematological, biochemical, and digestive enzyme profiles in the fingerlings of Labeo rohita. The 96-h LC₅₀ of hexavalent chromium was found to be 15.76 mg/L. Further, the toxicity study was conducted with four different sub-lethal concentrations of 96-h LC₅₀ viz. 1/40th, 1/20th, 1/10th, and 1/5th respectively. The blood samples from the control and treated groups exposed to different concentrations were examined for various physiological parameters. The obtained data showed that, with the increase in sub-lethal concentration, a significant decrease (p < 0.05) in red blood cell (RBCs), hemoglobin (Hb), and hematocrit (Hct) was observed, while total white blood cell (WBCs), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) increased significantly (p < 0.05) in all the treatments. Fishes exposed to chromium for 30 days responded by becoming hyperglycemic, hyperproteineric, and hypoalbuminemia with a gradual rise in concentrations. Alteration in the intestinal digestive enzyme profiles was also observed after 30 days of study. The activity of protease (89.76%), and amylase (41.88%) decreased in the intestine with the highest concentration compared to the control. Conversely, compared to the control, the highest concentration resulted in an increase (146%) in lipase activity. Overall, this study has greatly enhanced our comprehension of the impact of chromium toxicity on various hematological, biochemical, and digestive enzyme parameters in Labeo rohita.

Molecular ecotoxicology facilitates the mechanistic understanding of chemical-organism interactions and the establishment of frameworks to link molecular events to adverse outcomes. However, the foundation of this sub-discipline must remain focused on the necessity to generate insight at levels of biological organization beyond the individual, namely the population, community, and ecosystem levels, and to strive towards ecological relevance. As planet Earth continues to experience unprecedented levels of chemical pollution, causing significant impact to the integrity and functionality of ecosystems, research efforts in molecular ecotoxicology must prioritize experimentation that quantitatively incorporates the influence of non-chemical stressors to enhance the predictability of chemical-driven effects at the population level and beyond. Here, perspectives on the challenge to transition experimental data to environmentally relevant scenarios are offered in an attempt to highlight the critical role of molecular ecotoxicology in protecting and supporting ecosystems threatened by chemical pollution.

Yessotoxin (YTX) is a disulfated toxin produced by harmful dinoflagellates and causes risks to aquatic animals. Polystyrene (PS) microplastics could absorb toxins in seawaters but pose threats to organism growth. In this study, the combined toxic effects of YTX (0, 20, 50, and 100 µg L^-1) and PS (0, 5, and 10 µg mL^-1) on the survival, reproduction, and population growth of marine rotifer Brachionus plicatilis at 20 °C, 25 °C, and 30 °C were evaluated. Results indicated that the survival time (S), time to first batch of eggs (F_t), total offspring per rotifer (O_t), generational time (T₀), net reproduction rate (R₀), intrinsic growth rate (r_m), and population growth rate (r) of rotifers were inhibited by YTX and PS at 25 °C and 30 °C. Low temperature (20 °C) improved the life-table parameters T₀, R₀, and r_m at YTX concentrations less than 100 µg L^-1. Temperature, YTX, and PS had interactive effects on rotifers' S, F_t, O_t, T₀, R₀, r_m, and r. The combined negative effects of YTX and PS on rotifers' survival, reproduction, and population growth were significantly enhanced at 30 °C. These findings emphasized the importance of environmental temperature in studying the interactive effects of microplastics and toxins on the population growth of zooplankton in eutrophic seawaters.