Existing mutagenicity tests for metazoans lack the direct observation of enhanced germline mutation rates after exposure to anthropogenic substances, therefore being inefficient. Cadmium (Cd) is a metal described as a mutagen in mammalian cells and listed as a group 1 carcinogenic and mutagenic substance. But Cd mutagenesis mechanism is not yet clear. Therefore, in the present study, we propose a method coupling short-term mutation accumulation (MA) lines with subsequent whole genome sequencing (WGS) and a dedicated data analysis pipeline to investigate if chronic Cd exposure on Chironomus riparius can alter the rate at which de novo point mutations appear. Results show that Cd exposure did not affect the basal germline mutation rate nor the mutational spectrum in C. riparius, thereby arguing that exposed organisms might experience a range of other toxic effects before any mutagenic effect may occur. We show that it is possible to establish a practical and easily implemented pipeline to rapidly detect germ cell mutagens in a metazoan test organism. Furthermore, our data implicate that it is questionable to transfer mutagenicity assessments based on in vitro methods to complex metazoans.

Vehicle emissions are an important source of particulate matter (PM) in urban areas and have well-known adverse health effects on human health. Oxidative potential (OP) is used as a quantification metric for indexing PM toxicity. In this study, by using a liquid spot sampler (LSS) and the dithiothreitol (DTT) assay, the diurnal OP variation was assessed at a ground-level urban monitoring station. Besides, since the monitoring station was adjacent to the main road, the correlation between OP and traffic volume was also evaluated. PM components, including metals, water-soluble inorganic aerosols (WSIAs), black carbon (BC), and polycyclic aromatic hydrocarbons (PAHs), were also simultaneously monitored. The daytime and evening mean ± std volume-normalized OP (OPv) were 0.46 ± 0.27 and 0.48 ± 0.26 nmol/min/m³, and exhibited good correlations with PM₁.₀ and BC; however, these concentrations were only weakly correlated with mass-normalized OP (OPm). The mean ± std OPm was higher in the daytime (41.3 ± 13.8 pmol/min/μg) than in the evening (36.1 ± 11.5 pmol/min/μg). According to the PMF analysis, traffic emissions dominated the diurnal OP contribution. Organic matter and individual metals associated with non-exhaust traffic emissions, such as Mn, Fe, and Cu, contributed substantially to OP. Diurnal variations of PAH concentrations suggest that photochemical reactions could enhance OP, highlighting the importance of atmospheric aging on PM toxicity.

Our previous study showed that 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), the most biotoxic polybrominated diphenyl ether (PBDE) in the marine environment, induced apoptosis in rainbow trout gonadal RTG-2 cells. This effect occurred via ROS- and Ca²⁺-mediated apoptotic pathways, but the exact mechanism remains unknown. Therefore, in the present study, the possible mechanism was examined from the perspective of ROS-induced oxidative stress. The results showed that BDE-47 exposure significantly elevated the malondialdehyde (MDA) contents and the intracellular GSH/GSSG ratio, and the GSH-related enzymes were greatly altered, indicating alteration of the redox status and occurrence of oxidative stress. The mRNA levels of nuclear factor E2-related factor 2 (Nrf2) and its downstream genes were simultaneously greatly elevated. The p38 mitogen-activated protein kinase (MAPK) signaling pathway was also found to be induced by BDE-47 exposure. The addition of SB203580, a p38 MAPK inhibitor resulted in decreased apoptosis. In addition, supplementation with Ca²⁺ inhibitors BAPTA-AM positively affected p38 MAPK activation. Taken together, BDE-47 exposure resulted in the occurrence of oxidative stress and initiated the Nrf2-mediated antioxidant response. Subsequently, the altered redox status induced p38 MAPK activation, which played a pivotal role in the cellular apoptosis of RTG-2 cells.

Glyphosate herbicide is ubiquitously used in agriculture and weed control. It has now been identified in aquatic ecosystems worldwide, where numerous studies have suggested that it may have both suppressive and stimulatory effects on diverse non-target organisms. We cultured natural biofilms from a hypereutrophic environment to test the effects on periphytic diatoms of exposure to a glyphosate-based herbicide formulation at concentrations from 0 to 10 mg L⁻¹ of active ingredient. There were clear and significant differences between treatments in diatom community structure after the 15-day experiments. Diversity increased more in low glyphosate treatments relative to higher concentrations, and compositional analyses indicated statistically significant differences between glyphosate treatments. The magnitude of change observed was significantly correlated with glyphosate-based herbicide concentration. Our results show that glyphosate-based herbicides have species-selective effects on benthic diatoms that may significantly alter trajectories of community development and therefore may affect benthic habitats and whole ecosystem function.

Urbanisation of riverine landscape is an increasing threat to the functionality of river ecosystems. In this study, we identify and classify macroinvertebrates indicator signature traits and ecological preferences.We hypothesised that urban pollution would differentially influence the distribution of macroinvertebrate traits and ecological preferences along a gradient of water quality deterioration. Hence, we identified and classified potential biological indicators traits and ecological preferences that were deemed tolerant of or sensitive to urban pollution gradient in the Niger Delta region of Nigeria. Physico-chemical variables (water temperature, depth, flow velocity, dissolved oxygen, biochemical oxygen demand, electrical conductivity (EC), nitrate, phosphate), and macroinvertebrates were collected from 2008 to 2012 seasonally during the wet and dry seasons once in a month in 11 stations in eight river systems. The results based on RLQ, fourth-corner and Kruskal-Wallis analyses indicate that traits/ecological preferences such as tegumental/cutaneous respiration, cased/tubed body armouring, a preference for silty water, bivoltinism, burrowing and a high tolerance for oxygen depletion, were statistically significantly associated with the heavily impacted stations. These traits were positively correlated with physico-chemical variables such as EC, nitrate and phosphate indicative of urban pollution. On the other hand, traits/ecological preferences such as permanent attachment, crawling, swimming, univoltinism and a moderate sensitivity to oxygen depletion were associated with the least impacted stations and were negatively correlated with physico-chemical variables indicative of urban pollution. Overall, the observed differential responses of traits and ecological preferences to urban pollution along a gradient of water quality impairment suggest that traits and ecological preferences can serve as useful biological indicators and thus supports the growing evidence of the utility of the trait-based approach.

Knowledge of the concentration of the bioavailable forms of mercury in the soil is necessary, especially, if these soils contain above-limit total mercury concentrations. The bioavailability of mercury in soil samples collected from the vicinity of abandoned cinnabar mines was evaluated using diffusive gradients in the thin films technique (DGT) and mercury phytoaccumulation by vegetables (lettuce, spinach, radish, beetroot, carrot, and green peas). Mercury was accumulated primarily in roots of vegetables. The phytoaccumulation of mercury into edible plant parts was site-specific as well as vegetable species-specific. The mercury concentration in edible parts decreased in the order: spinach leaf ≥ lettuce leaf ≥ carrot storage root ≥ beetroot storage root > radish storage root > pea legume. The translocation index as well as the target hazard quotient indicate the possible usability of soils from the vicinity of abandoned cinnabar mines for planting pod vegetables (peas). A strong positive correlation (r = 0.75 to 0.92, n > 30, p < 0.05) was observed between mercury concentration in secondary roots, the storage roots, leaves of vegetables and the flux of mercury from soil to the DGT units, and the effective concentration of mercury in soil solutions.

Rhizospheric microorganisms such as denitrifying bacteria are able to affect ‘rhizobioaugmention’ in aquatic plants and can help boost wastewater purification by benefiting plant growth, but little is known about their effects on the production of plant root exudates, and how such exudates may affect microorganismal nitrogen removal. Here, we assess the effects of the rhizospheric Pseudomonas inoculant strain RWX31 on the root exudate profile of the duckweed Spirodela polyrrhiza, using gas chromatography/mass spectrometry. Compared to untreated plants, inoculation with RWX31 specifically induced the exudation of two sterols, stigmasterol and β-sitosterol. An authentic standard assay revealed that stigmasterol significantly promoted nitrogen removal and biofilm formation by the denitrifying bacterial strain RWX31, whereas β-sitosterol had no effect. Assays for denitrifying enzyme activity were conducted to show that stigmasterol stimulated nitrogen removal by targeting nitrite reductase in bacteria. Enhanced N removal from water by stigmasterol, and a synergistic stimulatory effect with RWX31, was observed in open duckweed cultivation systems. We suggest that this is linked to a modulation of community composition of nirS- and nirK-type denitrifying bacteria in the rhizosphere, with a higher abundance of Bosea, Rhizobium, and Brucella, and a lower abundance of Rubrivivax. Our findings provide important new insights into the interaction of duckweed with the rhizospheric bacterial strain RWX31 and their involvement in the aquatic N cycle and offer a new path toward more effective bio-formulations for the purification of N-polluted waters.

The rapid development of China's industrial economy and implementation of air pollution controls have led to great changes in sulfur (S), nitrogen (N) and base cation (BC) deposition in the past three decades. We estimated China's anthropogenic BC emissions and simulated BC deposition from 1985 to 2015 with a five-year interval using a multilayer Eulerian model. Deposition of S and N from 2000 to 2015 with a five-year interval was simulated with the EMEP MSC-W model and the Multi-resolution Emission Inventory of China (MEIC). The critical load (CL) and its exceedance were then calculated to evaluate the potential long-term acidification risks. From 1985 to 2005, the BC deposition in China was estimated to have increased by 16 % and then decreased by 33 % till 2015. S deposition was simulated to increase by 49 % from 2000 to 2005 and then decrease by 44 % in 2015, while N deposition increased by 32 % from 2000 to 2010 with a limited reduction afterward. The maximum CL of S was found to increase in 67 % of mainland China areas from 1985 to 2005 and to decline in 55 % of the areas from 2005 to 2015, attributed largely to the changed BC deposition. Consistent with the progress of national controls on SO₂ and NOX emissions, the CL exceedance of S increased from 2.9 to 4.6 Mt during 2000–2005 and then decreased to 2.5 Mt in 2015, while that of N increased from 0.4 in 2000 to 1.2 Mt in 2010 and then decreased to 1.1 Mt in 2015. The reduced BC deposition due to particle emission controls partially offset the benefit of SO₂ control on acidification risk reduction in the past decade. It demonstrates the need for a comprehensive strategy for multi-pollutant control against soil acidification.

Microplastic (MP) occurrence is a major global issue, though data on MP occurrence in the Philippines is limited and the potential effects of MPs on biota are still poorly studied. MP occurrence in fishes remains a concern, especially in economically and ecologically important species such as Siganus spp. This study determined MP occurrence in the gastrointestinal tract of wild rabbit fishes from Tañon Strait, the largest marine protected area in the Philippines. Siganus canaliculatus (n = 65), S. spinus (n = 17), S. guttatus (n = 5), S. virgatus (n = 8) and S. punctatus (n = 1) were sampled from the north and south of the strait. All MPs isolated from the gut of the rabbit fishes except for fibers were chemically analyzed by ATR-FTIR spectroscopy; an established library was used to determine the polymeric identities. Five particles were confirmed as polyester, polyamide, polyethylene or phenoxy resin MPs. The average MP abundance was 0.05 items/individual (S. virgatus > S. guttatus > S. canaliculatus > S. spinus = S. punctatus), which is comparable to studies conducted in other locations using similar methods. Fibers were counted (1556 in total), but not chemically analyzed. The low MP abundance in the samples may be attributed to the capability of rabbit fishes to discriminate food preferences. However, the risks associated with MPs should not be underestimated, especially as all parts of the fishes—including the gut—are utilized as human foods in the Philippines and many other Asian countries.

Cadmium (Cd) pollution in the environment could cause toxic damage to animals and humans. MAPK pathways could regulate their downstream inflammatory factors, and plays a crucial role in necrosis. Since the swine kidney tissue is an important accumulation site of Cd and target organ of its toxic damage, but the damage form of Cd to swine kidney and the role of MAPK pathways in it are still not clear, we selected six week old weaned piglets as the research object, and fed a diet supplemented CdCl₂ (20 mg/kg) to establish the model of liver injury induced by Cd. The expressions and phosphorylation of MAPK pathways (ERK, JNK, p38), expression levels of inflammatory factors (TNF-α, NF-κB, iNOS, COX-2 and PTGE) and necrosis related genes (MLKL, RIPK1, RIPK3 and FADD) and heat shock proteins (HSPs) were detected by RT-PCR and Western blot. H.E. staining was used to determine the damage of kidney caused by Cd exposure. The results showed that Cd exposure could activate p38 and JNK pathway phosphorylation, rather than ERK 1/2, up regulated the expressions of inflammatory factors, finally induced programmed necrosis (increasing the expressions of MLKL, RIPK1, RIPK3 and FADD) in swine kidney. Our study elucidated the mechanism of Cd-damage to swine kidney and the relationship among MAPK pathways, inflammatory factors and programmed necrosis in swine.