Transformation of copper oxide nanoparticles as affected by ionic strength and its effects on the toxicity and bioaccumulation of copper in zebrafish embryo.

This study aimed to investigate the transformation of copper oxide nanoparticles (CuO NPs) in aquatic environments under different ionic strength and further examine its effects on copper toxicity and bioaccumulation by monitoring the responses and uptake behaviours of zebrafish embryo. Ionic strength (IS) was simulated according to surface water (1.5 mM), groundwater (15 mM), and wastewater (54 mM), representing low-, mid-, and high-IS water, respectively. At the highest exposure of 10 mg CuO/L, zebrafish larvae mortality was increased from 21.3% to 33.3%, when IS decreased from 54 to 1.5 mM. Low-IS solution also caused the highest numbers of delayed hatching embryo (81.3%) and opaque yolk deformation (36.3%). Copper bioaccumulation markedly increased when larvae were exposed to low-IS water (35%) relative to high-IS water (15%). Exposing to low-IS particularly enhanced copper uptake (~15 ng Cu/g inside embryo), facilitating the copper accumulation in the heart of larvae, whereas aggregated CuO NPs (>500 nm) in mid- and high-IS water were blocked from the embryo and found abundantly in the body axis and tail. Results indicate that CuO NPs in low-IS solutions rapidly form the relatively small CuO NP aggregates with a high copper dissolution, which would pose great concern for aquatic organisms.

Critical factors for enhancing the bioremediation of a toxic pollutant at high concentrations in groundwater: Toxicity evaluation, degrader tolerance, and microbial community.

Groundwater near refinery and natural gas plants often contain elevated concentrations of toxic sulfolane. Studies on any concentration of sulfolane are limited. Column experiment was conducted to investigate the effects of adding a low dose of H2O2 and nutrient on bioremediation. Vibrio fischeri light inhibition test was used evaluate the toxicity of effluents. The continuous column experiment conditions were sulfolane at 100 mg L-1, dissolved oxygen at 7 mg L-1, absence of phosphorus, and very short hydraulic retention time (7.9 h). A low dose of H2O2 (5.88 mM) enhanced the sulfolane (27.1%) and COD removal (11.8%) in comparison with the control set. Adding nutrient increased bicinchoninic acid protein assay levels, sulfolane removal (99.6%) and COD removal (80.3%). Addition of both H2O2 and nutrient further improved COD removal (90.3%) and COD/sulfolane ratio (0.90) and toxicity removal (Vibrio fischeri light inhibition ratio < 1%). Batch experiment indicated the degraders tolerated sulfolane up to 400 mg L-1. The DGGE method and dendrogram analysis were utilized to investigate the changes of degrader community structure.

Electricity production and benzene removal from groundwater using low-cost mini tubular microbial fuel cells in a monitoring well.

A low-cost mini tubular microbial fuel cell (MFC) was developed for treating groundwater that contained benzene in monitoring wells. Experimental results indicate that increasing the length and density, and reducing the size of the char particles in the anode effectively reduced the internal resistance. Additionally, a thinner polyvinyl alcohol (PVA) hydrogel separator and PVA with a higher molecular weight improved electricity generation. The optimal parameters for the MFC were an anode density of 1.22 g cm-3, a coke of 150 µm, an anode length of 6 cm, a PVA of 105,600 g mol-1, and a separator thickness of 1 cm. Results of continuous-flow experiments reveal that the increasing the sets of MFCs and connecting them in parallel markedly improved the degradation of benzene. More than 95% of benzene was removed and electricity of 38 mW m-2 was generated. The MFC ran continuously up to 120 days without maintenance.

Innovative encapsulated oxygen-releasing beads for bioremediation of BTEX at high concentration in groundwater.

Both a low concentration of dissolved oxygen and the toxicity of a high concentration of BTEX inhibit the bioremediation of BTEX in groundwater. A novel method of preparing encapsulated oxygen-releasing beads (encap-ORBs) for the biodegradation of BTEX in groundwater was developed. Experimental results show that the integrality and oxygen-releasing capacity of encap-ORBs exceeded those of ORBs. The use of polyvinyl alcohol (PVA) with high M.W. to prepare encap-ORBs improved their integrality. The encap-ORBs effectively released oxygen for 128 days. High concentration of BTEX (480 mg L-1) inhibited the biodegradation by the free cells. Immobilization of degraders in the encap-ORB alleviated the inhibition. Scanning electron microscope analysis reveals that the BTEX degraders grew on the surface of encap-ORB after bioremediation. The above results indicate that the encap-ORBs were effective in the bioremediation of BTEX at high concentration in groundwater.

Alleviation of metal and BTEX inhibition on BTEX degradation using PVA-immobilized degrader: kinetic model of BTEX degradation.

Alleviation of metal inhibition on BTEX degradation using PVA-immobilized degrader (Mycobacterium sp. CHXY119) was investigated. When BTEX of 29 mg L(-1) [B:T:E:X = 1:1:1:1 (mg)] was used, more than 99 % of BTEX was simultaneously degraded by the free cells within 170 h. In contrast, BTEX of 114-172 mg L(-1) seriously inhibited degradation. High concentrations of metals (Mn(2+): 15, Ni(2+): 10, and Zn(2+): 10 mg L(-1)) also strongly inhibited BTEX degradation by the free cells at BTEX of 29 mg L(-1). Immobilization of degraders alleviated the inhibition of BTEX and heavy metals at high concentrations. A modified non-competitive inhibition model well described the BTEX degradation by the free and immobilized cells in the absence and presence of metal ions (R (2) = 0.92-0.99). The above results provide valuable information on treatment of metal-BTEX co-contaminated wastewater by the immobilized degrader.

Improvement of Corrosion and Wear Resistance of CoCrNiSi0.3 Medium-Entropy Alloy by Sputtering CrN Film.

In this study, Co, Cr, and Ni were selected as the equal-atomic medium entropy alloy (MEA) systems, and Si was added to form CoCrNiSi0.3 MEA. In order to further improve its wear and corrosion properties, CrN film was sputtered on the surface. In addition, to enhance the adhesion between the soft CoCrNiSi0.3 substrate and the super-hard CrN film, a Cr buffer layer was pre-sputtered on the CoCrNiSi0.3 substrate. The experimental results show that the CrN film exhibits a columnar grain structure, and the film growth rate is about 2.022 µm/h. With the increase of sputtering time, the increase in CrN film thickness, and the refinement of columnar grains, the wear and corrosion resistance improves. Among all CoCrNiSi0.3 MEAs without and with CrN films prepared in this study, the CoCrNiSi0.3 MEA with 3 h-sputtered CrN film has the lowest wear rate of 2.249 × 10-5 mm3·m-1·N-1, and the best corrosion resistance of Icorr 19.37 µA·cm-2 and Rp 705.85 Ω·cm2.

Copper emission during thermal treatment of simulated copper sludge.

This study evaluates Cu emissions in air-particulate and gas phases during thermal treatment of simulated copper sludge by a rotary kiln. Influences of operating parameters, including treatment temperature (400-700 degrees C), rotary speed (0.89-2.00 rpm) and copper content in sludge (1% to 5% by weight) on copper emissions were investigated. The toxicity characteristic leaching procedure (TCLP) and scanning electron microscopy (SEM) were also conducted to evaluate copper leaching and the surface structure of thermally treated sludge, respectively. The results indicated that (1) low Cu emissions in air-particulate and gas phases were associated with the two operating conditions of 400-500 degrees C at 0.89-1.39 rpm and 600-700 degrees C at 2.00 rpm; (2) temperatures and rotary speeds did not affect gaseous copper emission, except for the operating condition of 400 degrees C at 2.00 rpm; (3) rising copper content of sludge at 600 degrees C and 2.00 rpm increased the particulate copper emission, but not the gaseous copper emission; (5) the TCLP copper leaching concentrations of sludge treated at 400 degrees C were obviously higher than those treated at 500-700 degrees C; however, all of the thermally treated products agreed with the Taiwan EPA TCLP regulations.

Performance of bioelectrochemical systems in treating exhaust gas with power generation: Effects of shock-load, shut-down episodes and microbial community.

A diffusive packed anode-bioelectrochemical (Dpa-Bes) system was constructed by feeding waste gas from the cathode to the anode tank in DPa-Bes through a proton exchange membrane (PEM). The high removal of oxygen by the PEM and the effective combination of the two packing materials reduced the electron loss and enhanced the proton transfer capacity, promoting the removal of acetone from the exhaust gas and increasing the output power. The maximum acetone removal efficiency of the modified Dpa-Bes reached ∼99 % after seven days of closed-circuit operation, with a 3.2-fold increase in maximum power density and a 2.27-fold increase in closed-circuit voltage relative to those of the unmodified Dpa-Bes. When the acetone concentration was 2400 ppm, the removal efficiency was 73.22 % and the elimination capacity was at its highest value of 290.21 g/m3/h. Microbial analysis revealed that the conductive filter contained abundant facultative and anaerobic bacteria, whereas the non-conductive filter was rich in aerobic bacteria. The abundance of anaerobic and facultative microorganisms in Dpa-Bes was much higher than in the unmodified Dpa-Bes, and the dominant bacteria were Flavobacterium and Ferruginibacter.

Waste expanded polystyrene modified with H2SO4/biodegradable chelating agent for reuse: As a highly efficient adsorbent to remove fluoroquinolone antibiotic from water.

Untreated wastewater containing fluoroquinolone antibiotics poses serious hazards to aquatic species and human health; therefore, treatment of waste expanded polystyrene (EPS) is a crucial environmental matter. In this study, waste EPS was modified with a H2SO4/biodegradable chelating agent, [S,S]-ethylenediamine-N,N'-disuccinic acid (EDDS), and used for highly efficient adsorption of the fluoroquinolone antibiotic ciprofloxacin. When ciprofloxacin of 25 mg/L was used, the H2SO4-modified EPS (EPSH2SO4) adsorbed 60.5% of the ciprofloxacin. During sulfonation, adding a low dose of EDDS markedly improved the adsorption ability of EPSH2SO4+EDDS. The optimal modification conditions were 95% H2SO4, 0.002 M EDDS, 80 °C, and 40 min. The increased adsorbent doses enhanced the adsorption. Approximately 0.2 g/L of EPSH2SO4+EDDS could effectively adsorb 97.8% of the ciprofloxacin (554.3 mg/g) within 30 min. Solution pH0 greatly influenced the adsorption, and the most suitable pH0 was 6. The Langmuir isotherm accurately described the adsorption behaviors of both EPSH2SO4 and EPSH2SO4+EDDS (R2 = 0.997-0.998). The adsorption ability of EPSH2SO4+EDDS (qmax = 1250 mg/g) was 32 times higher than that of EPSH2SO4 (qmax = 38.6 mg/g). A total of 1 M HCl effectively regenerated the exhausted adsorbent. The optimal solid/liquid ratio and time were 0.08 g/20 mL and 60 min, respectively. The regenerated EPSH2SO4+EDDS maintained a high adsorption ability (87.2%) after 10 regeneration cycles. The results thus indicate that the EPSH2SO4+EDDS adsorption-regeneration process is a potential approach to remove ciprofloxacin from water.

Rapid modification of waste expanded polystyrene with H2SO4/trace persulfate in one pot for effective adsorption of fluoroquinolone antibiotic and its regeneration.

Norfloxacin, a fluoroquinolone antibiotic, is widely used to treat microbial infections. However, untreated norfloxacin-containing wastewater poses serious threats to the ecosystem and human health. The treatment of waste expanded polystyrene (EPS) by landfilling or incineration could cause environmental problems. In this research, the feasibility of converting EPS into a valuable adsorbent for norfloxacin was evaluated. Results showed that EPS treated with H2SO4 (EPSH2SO4) effectively adsorbed norfloxacin. The optimal sulfonation conditions were 95% H2SO4 and 100 °C. Addition of 0.001 M of persulfate during sulfonation obviously shortened the sulfonation time to 7.5 min, and the adsorption ability of modified EPS increased with increasing persulfate dose. Under the experimental conditions of 25 mg L-1 norfloxacin, pH0 6.2, and 0.4 g L-1 EPSH2SO4+persulfate (dry weight), 97.2% of norfloxacin could be removed after 30 min of adsorption. The adsorption ability of EPSH2SO4+persulfate decreased with increasing solution pH0, and the optimal pH0 was 6.2. The Langmuir isotherm best described the adsorption behavior of EPSH2SO4+persulfate (qmax = 140.9 mg L-1, b = 1.97 L mg-1, R2 = 0.9992). 1 M HCl effectively regenerated the exhausted EPSH2SO4+persulfate at the optimal solid/solution ratio of 8 g L-1. EPSH2SO4+persulfate maintained excellent adsorption capacity (>80.9%) after eight adsorption-regeneration cycles.

Keratin particles generated from rapid hydrolysis of waste feathers with green DES/KOH: Efficient adsorption of fluoroquinolone antibiotic and its reuse.

Fluoroquinolone antibiotics are widely used in human and veterinary medicine. However, untreated fluoroquinolone seriously threatens the ecosystem and human health. In this study, deep eutectic solvents (DESs) were applied for the hydrolysis of waste feathers, and the keratin particles (KPs) in a low-cost teabag were utilized to adsorb fluoroquinolone norfloxacin. Results showed that choline chloride/ethylene glycol DES rapidly hydrolyzed feathers within 10 min, and the undissolved particles effectively adsorbed norfloxacin. Adding KOH markedly shortened the hydrolysis time (6 min) and increased the adsorption ability of KPs. The optimum hydrolysis conditions were DES ratio of 1 g: 4.67 g, KOH of 35.68 g L-1, and temperature of 90 °C. When KPDES+KOH of 2 g L-1, norfloxacin of 25 mg L-1, and pH0 7 were used, 94% of norfloxacin was removed in 60 min. A low-cost teabag effectively separated the KPs from the solution after adsorption and did not decrease the adsorption ability of the KPs. The Langmuir isotherm model well described the adsorption behavior of KPsDES+KOH (qmax = 79.36 mg g-1, R2 = 0.9972). In addition, acetone efficiently regenerated the exhausted KPsDES+KOH. The KPs maintained >80% of its adsorption ability after seven cycles of regeneration.

Evaluation use of bioaugmentation and biostimulation to improve degradation of sulfolane in artificial groundwater.

Column systems were used to evaluate the effectiveness of different bioremediation methods (biostimulation (BS) and bioaugmentation (BA)) in treating sulfolane-contaminated groundwater. Batch test results confirmed that Cupriavidus sp. Y9 (Y9) was the most effective strain for BA. The optimal ratio of added native bacteria to Y9 was 10:3. The BA column adapted to a high sulfolane concentration (150 mg L-1) more rapidly and had higher sulfolane removal efficiency (90%) than did the BS column. The change in the biotoxicity of sulfolane-contaminated groundwater upon bioremediation, according to a Microtox test, revealed decreases in the inhibition of the passing of light by the BS column and BS + BA column of 38% and 63%, respectively. These results reveal that combining BS with BA can reduce the biotoxicity of sulfolane. The column tests confirmed the most effective added bacterium in BA, the operating conditions for high-efficiency bioremediation, and possible problems in its future application. The results provide an important reference for the design of methods for the remediation of contaminated sites.

Treatment and toxicity evaluation of methylene blue using electrochemical oxidation, fly ash adsorption and combined electrochemical oxidation-fly ash adsorption.

Treatment of a basic dye, methylene blue, by electrochemical oxidation, fly ash adsorption, and combined electrochemical oxidation-fly ash adsorption was compared. Methylene blue at 100 mgL(-1) was used in this study. The toxicity was also monitored by the Vibrio fischeri light inhibition test. When electrochemical oxidation was used, 99% color and 84% COD were removed from the methylene blue solution in 20 min at a current density of 428 Am(-2), NaCl of 1000 mgL(-1), and pH(0) of 7. However, the decolorized solution showed high toxicity (100% light inhibition). For fly ash adsorption, a high dose of fly ash (>20,000 mgL(-1)) was needed to remove methylene blue, and the Freundlich isotherm described the adsorption behavior well. In the combined electrochemical oxidation-fly ash adsorption treatment, the addition of 4000 mgL(-1) fly ash effectively reduced intermediate toxicity and decreased the COD of the electrochemical oxidation-treated methylene blue solution. The results indicated that the combined process effectively removed color, COD, and intermediate toxicity of the methylene blue solution.

Dispatcher-assisted cardiopulmonary resuscitation: Differential effects of landline, Mobile, and transferred calls.

BACKGROUND: Dispatcher-assisted cardiopulmonary resuscitation (DACPR) could improve the survival rate of out-of-hospital cardiac arrest (OHCA). However, the efficiency of DACPR varies. Our study compared the effectiveness of DACPR instructed via landline calls, mobile calls, and landline calls transferred to mobiles. METHOD: This prospective cohort study enrolled patients with OHCA between 1 July 2017 and 30 November 2018 in Taichung. Patients were divided into a mobile group and a landline group according to device used to call emergency medical services (EMS). The landline group was subdivided according to whether the call was transferred to a mobile. We compared the DACPR rate and call to chest compression time between groups. RESULTS: The study comprised 2404 cases after exclusion: 934 cases of DACPR via mobile and 1470 via landline. In the mobile group, DACPR rate (54% vs. 47.5%, P <  0.001) was higher and call to chest compression time (median: 156 s vs. 174 s P < 0.001) was shorter than in the landline group. In the transferred group, DACPR rate (72.7% vs. 28.8%, P <  0.001) was higher than in the non-transferred group, but no difference was observed in call to chest compression time (median: 173 s vs. 177 s, P = 0.69). CONCLUSION: According to this city-based prospective clinical study, communication over mobiles resulted in higher DACPR rate and shorter call to chest compression time than that over landlines. Transferring calls from a landline to a mobile could increase the DACPR rate without delaying the initiation of chest compression.

Effects of diesel vehicle emissions of polycyclic aromatic hydrocarbons on the surrounding environment and residents.

Ten stations alongside major thoroughfares were selected as exposure sites, while a small village located about 3 kilometers away from a main traffic route was selected as the control site. The concentrations of particulate matters with aerodynamic less than 2.5 microm (PM(2.5)) and elemental carbon (EC) at exposure sites were both higher than those at the control site. Daytime mean concentrations of total polycyclic aromatic hydrocarbons (t-PAHs), carcinogenic PAHs (car-PAHs), and Benzo(a)pyrene-equivalent dose (BaP(eq)) at exposure sites were all about twice as high as those at the control site. A significant relationship between t-PAHs and EC was found, suggesting that most of the t-PAHs at exposure sites were contributed by diesel exhaust. Furthermore, the diagnostic ratios also show that diesel emissions were the dominant sources of PAHs at exposure sites. A multiple linear regression was applied to urinary 1-hydroxyprene (1-OHP) using four variables (exposure status, sex, smoker status, and incense burning) as independent variables. The results showed that the concentrations of 1-OHP in exposure groups were significantly (p < 0.001) higher than those in the control group. The explainable percentage for exposure status was 91.1%, indicating that the exposure factor, in comparison with other factors, has a dominant contribution to the concentration of 1-OHP. After subtracting the background levels of 1-OHP, the levels of urinary 1-OHP for residents exposed to the exhaust of 100 vehicles were about 0.062 microg/g creatinine.

Evaluation of the distribution patterns of Pb, Cu and Cd from MSWI fly ash during thermal treatment by sequential extraction procedure.

Municipal solid waste incinerator (MSWI) fly ash was frequently classified as hazardous materials as the metals' concentration of toxicity characteristic leaching procedure (TCLP) exceeded regulations. Many studies have focused on reducing the concentration of TCLP using thermal treatment and increasing the application of thermally treated slag. However, the metal patterns in MSWI fly ash with or without thermal treatment have seldom been addressed. The main objective of this study was evaluation of the distribution patterns of Pb, Cu and Cd from MSWI fly ash during thermal treatment by sequential extraction procedure. The experimental parameters included the form of pretreatment, the proportion of bottom ash (bottom ash/fly ash, B/F=0, 0.1 and 1) and the retention time. The results indicated that (1) In comparison to raw fly ash, the distribution patterns of Pb, Cu and Cd become stable in thermally treated slag. (2) Washing pretreatment caused the Pb pattern to become stable, while the influence on Cu and Cd were not significant. (3) The distribution patterns of Pb, Cu, and Cd became more stable as the retention time increased. (4) Adding bottom ash could make the distribution patterns of Pb and Cd more stable.

Phytoextraction of cadmium by Ipomoea aquatica (water spinach) in hydroponic solution: effects of cadmium speciation.

Phytoextraction is a promising technique to remediate heavy metals from contaminated wastewater. However, the interactions of multi-contaminants are not fully clear. This study employed cadmium, Triton X-100 (TX-100), and EDTA to investigate their interactions on phytotoxicity and Cd phytoextraction of Ipomoea aquatica (water spinach) in simulated wastewater. The Cd speciation was estimated by a chemical equilibrium model and MINEQL+. Statistic regression was applied to evaluate Cd speciation on Cd uptake in shoots and stems of I. aquatica. Results indicated that the root length was a more sensitive parameter than root weight and shoot weight. Root elongation was affected by Cd in the Cd-EDTA solution and TX-100 in the Cd-TX-100 solution. Both the root length and the root biomass were negatively correlated with the total soluble Cd ions. In contrast, Cd phytoextraction of I. aquatic was correlated with the aqueous Cd ions in the free and complex forms rather than in the chelating form. Additionally, the high Cd bioconcentration factors of I. aquatica (375-2227 l kg(-1) for roots, 45-144 l kg(-1) for shoots) imply that I. aquatica is a potential aquatic plant to remediate Cd-contaminated wastewater.

Degradation of Reactive Black 5 using combined electrochemical degradation-solar-light/immobilized TiO2 film process and toxicity evaluation.

The combined electrochemical oxidation-solar-light/immobilized TiO2 film process was conducted to degrade an azo dye, Reactive Black 5 (RB5). The toxicity was also monitored by the Vibrio fischeri light inhibition test. The electrochemical oxidation rapidly decolorized RB5 (55, 110 microM) with a supporting electrolyte of 2 gl(-1) NaCl at current density 277Am(-2) and pH 4. However, TOC mineralization and A(310) removal were low. Additionally, the treated solution showed high biotoxicity. RB5 at 110 microM significantly retarded the de-colorization efficiency by using the solar-light/immobilized TiO2 film process. The combined electrochemical oxidation-solar-light/immobilized TiO2 process effectively increased the removal of color, A(310), and TOC. The toxicity was also significantly reduced after 3h of solar irradiation. The results indicated that the low-cost combined process is a potential technique for rapid treatment of RB5.

Emission of Pb and PAHs from thermally co-treated MSWI fly ash and bottom ash process.

Municipal solid waste incinerator (MSWI) fly ash was regarded as a hazardous material because concentrations of TCLP leaching solution exceeded regulations. Previous studies have investigated the characteristics of thermally treated slag. However, the emissions of pollutant during the thermal treatment of MSWI fly ash have seldom been addressed. The main objective of this study was to evaluate the emission of Pb and PAHs from thermally co-treated MSWI fly and bottom ash process. The experimental parameters included the form of pretreatment, the proportion of bottom ash (bottom ash/fly ash, B/F=0, 0.1 and 1) and the retention time. The toxicity of thermally treated slag was also analyzed. The results indicated that (1) Pb emission occurred only in the solid phase and that PAHs were emitted from both solid and gas phases during thermal treatment process. (2) Washing pretreatment reduced not only the TCLP leaching concentration of Pb (from 15.75 to 1.67 mg/L), but also the emission of PAHs from the solid phase during thermal treatment process. (3) Adding bottom ash reduced the TCLP leaching concentration of thermally treated slag. (4) The concentration of Pb emission increased with retention time. (5) The thermal treatment reduced the toxicity of raw fly ash effectively, the inhibition ratio of raw fly ash and thermal treated slag were 98.71 and 18.35%, respectively.

Uptake of BDE-209 on zebrafish embryos as affected by SiO2 nanoparticles.

It was hypothesized that interactions between emerging contaminants such as decabromodiphenyl ether (BDE-209) and nanoparticles (NPs) such as nano-SiO2 (nSiO2), can affect contaminant transport in the aquatic environment and its ecotoxicity. This study assessed the influence of nSiO2 on the uptake of BDE-209 by zebrafish embryo. The distribution of BDE-209 and nSiO2 on the external chorion and the internal embryo mass (i.e., dechorionated embryo) was measured. For single exposure of nSiO2 to zebrafish embryo, separately, results showed that nSiO2 accumulation on the chorion surface was higher than that in the dechorionated embryo. The nSiO2 accumulation on the chorion surface was 129-200 mg-nSiO2/g-chorion at 48 h post fertilization, hpf, of exposure time, whereas the equilibrium adsorption of nSiO2 on the dechorionated embryo was ca. 0.42-0.54 mg-nSiO2/g-embryo at 6 hpf. Results showed that the formation of nSiO2-BDE-209 associates promoted both extracellular and intracellular uptake of BDE-209 by zebrafish embryo, thereby increasing the bioconcentration of BDE-209 on the chorion surface and in embryo. The results also revealed that the accumulation of BDE-209 on the chorion was remarkably greater than that on the dechorionated embryo at 48 hpf. The uptake of BDE-209 was 17.2 ±â€¯0.45 mg/g-chorion (or 86 ng-BDE-209/chorionated embryo) and 0.37 ±â€¯0.01 mg/g-embryo (or 18.6 ng-BDE-209/dechorionated embryo), respectively, when co-exposure of zebrafish embryos to BDE-209 and nSiO2. Results from the SEM and EDS analysis revealed that nSiO2 already passed through the chorion and adhered to the embryo surface/mass.