This constitutes the first study to report on the reduction in toxicity of the dinoflagellate algal toxin okadaic acid after novel pulsed light (PL) treatments where ecotoxicological assessment was performed using a miniaturised format of the conventional in vivo freshwater crustacean Daphnia sp. acute toxicity test. Bivalves accumulate this toxin, which can then enter the human food chain causing deleterious health effects such as diarrhetic shellfish poisoning. This miniaturised toxicological bioassay used substantially less sample volume and chemical reagents. Findings revealed a 24-h EC₅₀ of 25.87 μg/L for PL-treated okadaic acid at a UV dose of 12.98 μJ/cm² compared to a 24-h EC₅₀ of 1.68 μg/L for the untreated okadaic acid control, suggesting a 15-fold reduction in toxicity to Daphnia pulex. The bioassay was validated in this study and correlated well with the “classic” ISO format (r = 0.98) using the traditional reference chemical potassium dichromate (K₂Cr₂O₇). Reduction by up to 65% in PL-treated okadaic acid concentration was confirmed by LC-MS/MS analysis. Findings from this study have positive ecological, societal and enterprise implications, such as the development of PL technology for the prevention or reduce algal contamination of fisheries and aquaculture industries.

Visible foliar injury by ozone (ozone visible injury) is known as a biomarker to assess potential phytotoxicity of ozone. We investigated ozone visible injury in an ozone-sensitive poplar (Oxford clone) under a 2-year free-air controlled exposure (FACE) experiment and calculated three ozone indices (i.e., accumulative ozone exposure over 40 ppb during daylight hours (AOT40), phytotoxic ozone dose above a flux threshold of 0 nmol m⁻² s⁻¹ (POD₀), and the cumulative value of the ratio of hourly ozone uptake to net photosynthesis (ΣU/P ₙ) to assess the critical level (CL) at the time of the first symptom onset of ozone visible injury. We tested the hypothesis that ozone injury depends both on the amount of ozone entering a leaf and on the capacity for biochemical detoxification or repair with photosynthesis as a proxy. The CLs at the time of the first symptom onset of ozone visible injury were 19 ppm h for AOT40, 26 mmol m⁻² for POD₀, and 1.2 mol mol⁻¹ for ΣU/P ₙ in Oxford clone at the ozone FACE experiment. Our findings were then verified by 4-year observation-based data in central Italy on Oxford clone and white poplar (Populus alba L.). These observation-based data indicated that we found ozone visible injury in Oxford clone even though AOT40 was relatively low (11.7 ppm h). On the other hand, when values of POD₀ and ΣU/P ₙ exceeded over the CLs, the occurrence of initial symptoms in Oxford clone was shown. White poplar did not show ozone visible injury. ΣU/P ₙ of white poplar at the field sites reached ~1.0 mol mol⁻¹ (less than the CL = 1.2 mol mol⁻¹, which was obtained from O₃ FACE) during May–September, although the values of POD₀ were relatively high in white poplar (44–47 mmol m⁻² during May–September). The result implies that ozone injury may have occurred in poplars when stomatal ozone flux exceeded the critical range of tolerance due to the assimilate shortage for repair and defense against ozone stress.

The concentrations of 16 elements (Mg, Al, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Cd, Ba, and Pb) were determined in four fish species (Carassius auratus, Squaliobarbus curriculus, Pelteobagrus fulvidraco, and Silurus asotus) collected in the Xiang River, a mine-impacted river in Southern China. The mean values of the elements analyzed in fish muscles were in the decreasing order of Mg > Ca > Zn > Fe > Sr > Al > Cu > Mn > Ba > As > Cr > Pb > Ni > V > Co > Cd. The concentrations of Mg, Ca, Sr, Ba, and Cu in omnivorous species were found to be significantly higher (p < 0.05) than those in carnivorous species. Negative correlations observed between most element concentrations and fish sizes indicated the younger individuals accumulated more elements than the older ones. Principle component analysis and orthogonal partial least squares discriminant analysis were employed to characterize the effects on element bioaccumulation using the element concentration matrix. The elemental profiles preferred to cluster according to differences in fish species rather than in sampling sites. The potential health risk evaluated through Monte Carlo simulation showed no appreciable adverse impact on human health from exposure to trace elements in fish muscles through consumption.

In the present study, the combined effect of alumina nanoparticles into the Calophyllum inophyllum biodiesel blend and exhaust gas recirculation on the combustion, performance, and emission characteristics of a diesel engine was investigated. The alumina (Al₂O₃) nanoparticles with the mass fraction of 40 ppm were dispersed into the C. inophyllum biodiesel blend (20% of C. inophyllum biodiesel + 80% of diesel (CIB20)) by the ultrasonication process. Further, the exhaust gas recirculation was adopted to control the oxides of nitrogen (NOx) emissions of a diesel engine. The experiments were conducted on a single cylinder diesel engine with the diesel, CIB20, 20% of C. inophyllum biodiesel + 80% of diesel + 40 ppm Al₂O₃ nanoparticles (CIB20ANP40), CIB20 + 20% exhaust gas recirculation (EGR), and CIB20ANP40 + 20% EGR fuel samples at different load conditions. The results reveal that brake thermal efficiency of CIB20ANP40 fuel increased by 5.04 and 7.71% compared to the CIB20 and CIB20ANP40 + 20% EGR fuels, respectively. The addition of alumina nanoparticles to the CIB20 fuel, CO, and hydrocarbon (HC) emissions were was reduced compared to the CIB20 fuel. The smoke opacity was decreased with the addition of alumina nanoparticles to the CIB20 fuel by 7.3% compared to the CIB20 fuel. The NOx emissions for the CIB20ANP40 + 20% EGR fuel was decreased by 36.84, 31.53, and 17.67% compared to the CIB20, CIB20ANP40, and CIB20 + 20% EGR fuel samples at full load condition.

The main objective of this study was to determine how rat tapeworms affect the excretion of zinc and cadmium through rat feces. Male rats (Rattus norvegicus var. alba) were divided into four groups, and the experiment was conducted over a 6-week period. The control groups (00; 0T) were provided with a standard ST-1 rodent mixture and received 10.5 mg of Zn/week. Groups P0 and PT were fed a mixture supplemented with the hyperaccumulating plant Arabidopsis halleri at a dosage of 123 mg Zn/week and 2.46 mg Cd/week. Groups 0T and PT were infected with the rat tapeworm (Hymenolepis diminuta). Fecal samples were collected 24 h post exposure. Zinc and cadmium concentrations in rat feces were analyzed using inductively coupled plasma optical emission spectrometry. Tapeworm presence decreased the amount of metals excreted through the feces of the host throughout the entire experiment, with the exception of 1 week (control group). No statistically significant differences between zinc excretion rates in the control groups (00 and 0T) were detected at any time throughout the experiment. A statistically significant difference between zinc excretion rates (p < 0.05) in the exposed groups (P0 and PT) was detected in 2 of the 6 monitored weeks. Group PT excreted significantly less cadmium (p < 0.01) than group P0 did in three of the 6 weeks. Overall, our results indicate that tapeworms are able to influence the excretion of metals by their host. Tapeworms accumulate metals from intestinal contents. It is not clear whether tapeworms carry out this process before the host tissues absorb the metals from the intestines or the tapeworms accumulate metals excreted from the body of the host back to the intestines. Most likely, it is a combination of both phenomena.

Chromic oxide nanoparticles (Cr₂O₃ NPs) are widely used in commercial factories and can cause serious environmental problems. However, the mechanism behind Cr₂O₃ NP-induced phytotoxicity remains unknown. In this study, the effects of Cr₂O₃ NPs on the growth, chlorophyll fluorescence, SEM-EDS analysis, and chloroplast ultrastructure of soybean (Glycine max) were investigated to evaluate its phytotoxicity. The growth of soybean treated with various Cr₂O₃ NP suspensions (0.01, 0.05, 0.1, and 0.5 g L⁻¹) was significantly inhibited. Specially, shoot and root biomass decreased by 9.9 and 46.3%, respectively. Besides, the maximum quantum yield of PSII (Fv/Fm) as well as the photochemical quenching (qP) decreased by 8–22 and 30–37%, respectively, indicating that the photosynthetic system was damaged when treated with Cr₂O₃ NPs. Moreover, the inhibition was confirmed by the reduction of Rubisco and MDH enzyme activity (by 54.5–86.4 and 26.7–96.5%, respectively). Overall, results indicated that the damage was caused by the destruction of chloroplast thylakoid structure, which subsequently reduced the photosynthetic rate. Our research suggests that Cr₂O₃ NPs can be transported and cause irreversible damage to soybean plants by inhibiting the activity of electron acceptors (NADP+) and destroying ultrastructure of chloroplasts, providing insights into plant toxicity issues. Graphical abstract ᅟ

The adsorption performances of chloroform (TCM), carbon disulfide (CDS), and acetone (CP) were investigated and compared over self-prepared coconut shell-derived carbon (CDC) to study the adsorption behavior and mechanism of heteroatom (Cl, S, O)-containing volatile organic compounds (VOCs). The result indicates that the adsorption capacity of three typical VOCs obeys the sequence: TCM (361 mg/g) > CDS (194 mg/g) > CP (37 mg/g). However, desorption experiments show that adsorption intensity follows the order: CDS (165 °C) > TCM (147 °C) > CP (130 °C). The influence of surface oxygen-containing functional groups over CDC on adsorption performance was also studied by temperature programmed desorption (TPD) and in situ DRIFT spectra. It is implied that carbonyl in lactone and benzoquinonyl of CDC could affect VOC adsorption intensity by conjugation effect. Furthermore, adsorption isotherms of three VOCs were obtained through Grand Canonical Monte Carlo (GCMC) simulation and then fitted by classical isothermal models. Furthermore, the total adsorption potentials are calculated by potential theory, and the result follows the order: TCM (− 2.18 kJ/mol) > CDS (− 2.1 kJ/mol) > CP (− 1.5 kJ/mol). It is believed that the effect of magnetic susceptibility (χ) is more crucial than polarizability (∂) and the distance r between the interacting molecules for the potential difference.

A 6-year laboratory study was conducted to explore the performance of the vermifilter (VF) on reducing sewage sludge. Sewage sludge was found to be reduced significantly in the VF and exhibited a better performance of sludge reduction as compared with the conventional biofilter (BF), which could be traced through the nitrogen-rich organic matter. The nitrogen stable isotope technology was applied to study the matter flow of sewage sludge in the VF process and the influence of earthworms Eisenia fetida on sewage sludge reduction. Results showed that (1) the protein material could be consumed more than the polysaccharide and lipid materials, respectively, in the VF; (2) the presence of earthworms could enhance the consumption capacity of the VF on the protein-rich material of the sewage sludge; (3) earthworms played a leading role on the nitrogen lifting of the sewage sludge, leading to the performance difference of the effluent sludge or biofilm sludge between the VF and BF; (4) in the VF, nitrogen-isotope accumulation in either biofilms or earthworms happened more significantly in the lower layer than in the upper one, while nitrogen transfer of sewage sludge happened more significantly in the upper layer than in the lower one; (5) earthworms improved the feeding environment of organisms (microorganisms in biofilms, moth fly larvae, Limacidaes, and Lymnaeidaes); (6) biofilms, Limacidaes, and moth fly larvae performed better than leeches, Lymnaeidaes, and moth fly adults at nitrogen transfer of sewage sludge.

In what has become known as the Yusho incident, thousands of people in western Japan were poisoned by the accidental ingestion of rice bran oil contaminated with polychlorinated biphenyls (PCBs) and various dioxins and dioxin-like compounds. In this study, we investigated the accumulation patterns of 69 PCB congeners in the blood of Yusho patients in comparison with those of non-exposed controls. The blood samples were collected at medical check-ups in 2004 and 2005. To compare the patterns of PCB congeners, we calculated the concentration ratio of each congener relative to the 2,2′,4,4′,5,5′-hexaCB (CB153) concentration. The concentration ratios of tetra- and penta-chlorinated congeners in the blood of Yusho patients were significantly lower than those of controls. To examine the cytochrome P450 (CYP)-dependent metabolic potential of the 2,3′,4,4′5-pentaCB (CB118), CB153, and 2,3,3′,4,4′5-hexaCB (CB156) congeners, we conducted PCB-CYP (CYP1A1, CYP1A2, CYP2A6, and CYP2B6) docking simulation by in silico analysis. The docking models showed that human CYP1A1, CYP2A6, and CYP2B6 isozymes have the potential to metabolize CB118 and CB153. On the other hand, it was inferred that CB156 is difficult to be metabolized by these four CYP isozymes. These results indicate that CYP1 and CYP2 isozymes may be involved in the characteristic accumulation patterns of PCB congeners in the blood of Yusho patients.

The efficacy of a binary oxidant system, hydrogen peroxide (H₂O₂) and persulfate, was investigated for treatment of 1,4-dioxane (dioxane) and trichloroethene (TCE) co-contamination. Batch experiments were conducted to examine the catalytic efficiency of Fe²⁺ and NaOH-based activation, oxidant decomposition rates, contaminant degradation effectiveness, and competitive degradation effects. For NaOH activation, the oxidant decomposition rate was moderate and sustained during the entire test period of 96 h. However, dioxane degradation was limited (~ 33%). Conversely, the oxidants were depleted within 24 h for the Fe²⁺-activated system, and dioxane degradation was complete within 4 h. The activation and radical generation processes were different between Fe²⁺ and NaOH activation. Both dioxane and TCE underwent complete degradation in the co-contaminant experiment. The results of this study indicate that the Fe²⁺-catalyzed binary hydrogen peroxide-persulfate oxidant system is effective for oxidation of the tested contaminants separately and as co-contaminants.