Inactivation of antineoplastics in clinical wastewater by electrolysis

Wastewater from clinical institutions contains a considerable amount of toxic substances. Among the toxic substances, antineoplastics may induce carcinogenesis, teratogenesis, and the emergence of mutant microorganisms in the environment. Although the incineration or chemical treatments of disposed antineoplastics are recommended, a high energy during incineration and a careful quality control during chemical treatment are required. In this study, we determined the conditions for the electrolytic treatment of an antineoplastic, epirubicin hydrochloride (EH), using two platinum electrodes with a constant current of 100 mA. We analyzed the cytotoxicity, mutagenicity and antibacterial activity of electrolyzed EH and compared them with those of unelectrolyzed EH. Nearly 100% cytotoxicity, mutagenicity and antibacterial activity were eliminated and HPLC did not detect an EH molecule, in the case of electrolysis for 6 h. We also examined the biological cytotoxicities of electrolyzed irinotecan hydrochloride, vincristine sulfate, mitomycin C, paclitaxel, methotrexate and cisplatin, and found that 72.1-99.999% toxicity was eliminated by electrolysis under the same conditions. The biological toxicity of a mixture of these drugs was determined to be decreased by approximately 99% by electrolysis under the same conditions.     

Catalyst durability in steam reforming of thermally decomposed waste wood

Thermal gasification and reforming technologies applicable over a wide temperature range were investigated for high efficiency and for the calorific value of the gas evolved from organic waste such as woody debris. The durability of the reforming catalyst and the availability of catalyst regeneration were investigated using laboratory-scale catalytic reformers and a gasifier. Commercial Ni-based catalyst and calcined limestone (CaO) were applied to the reforming reaction. The results of woody waste gasification and reforming revealed the hydrogen concentration produced to be sustained at a high catalyst temperature of 1123 K, which prevented the catalyst from deactivating. The results also indicated that catalyst regeneration by air oxidation at the same temperature would be effective for enhancing catalytic activity.     

Formation of toxic chemicals including dioxin-related compounds by combustion from a small home waste incinerator

We investigated combustion in a small home waste incinerator and analyzed both flue gas and residual ash for formation of the dioxin-related compounds polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls and their precursors polychlorinated benzenes, polychlorinated phenols, polychlorinated diphenyl ethers, and polychlorinated biphenyls. Particularly, we investigated the effect of the incinerated material's composition on both the congener ratios of released compounds and the total concentration of all congeners of each compound. Eight different samples were prepared for incineration with four samples consist entirely paper, dead leaves, natural wood, or building materials. The remaining four samples contained mostly paper, but also other components such as fiber, non-chlorine-containing plastics, chlorine-containing plastics, and copper electric wire. The presence of non-chlorine-containing plastic in combustion samples did not increase overall dioxin or dioxin-precursor emissions. In contrast, chlorine-containing plastic resulted in a several-fold increase in total polychlorinated dioxins released, in both flue gas and residual ash. Copper wire resulted in a further several-fold increase in total polychlorinated dioxins and dioxin precursors released, with one exception: the addition of chlorine-containing plastic resulted in a many-fold increase in polychlorinated biphenyls, but only a modest further increase ( approximately 52%) with the further addition of copper. Homologue ratios tended toward higher-chlorine compounds as chlorine-containing plastic and Cu were added, but the results were far from uniform. Our results show that toxic dioxin release from small home waste incinerators must be considered significant, especially if even small amounts of chlorine-containing plastics or copper are burned.     

Fabric-filter-supported catalyst for removal of harmful solid and gaseous compounds in municipal waste incinerator exhaust gas: characteristics of NO x reduction

We have investigated a fabric-filter-supported catalyst for removing harmful solid and gaseous compounds simultaneously from municipal incinerator exhaust gas. We studied the ways in which the efficiency of NO _x removal is influenced by filter temperature, gas flow rate, and catalyst content. The reduction of the catalyst content by mechanical reverse washing was investigated, and the state of the catalyst supported in the fabric filter was also observed using a scanning electron microscope. The catalyst supported by the fabric filter showed a removal efficiency above 75% when the filter temperature was 200°C, the gas flow rate was 1 m/min, and the catalyst content of the fabric filter was above 300 g/m². The catalyst was supported uniformly on the fibers of the fabric filter, and fine catalyst particles remained on the fibers after mechanical reverse washing. Received: October 15, 1997 / Accepted: March 19, 1999     

Growth and Nitrogen Availability of Red Pine Seedlings under High Nitrogen Load and Elevated Ozone

To evaluate the effect of increasing nitrogen (N) deposition and tropospheric ozone (O₃) concentrations on N-saturated forest ecosystems, we investigated the response of Japanese red pine (Pinus densiflora), an N-saturation sensitive tree species, to increasing N load under elevated O₃ concentrations. One-year-old seedlings of red pine were treated with three levels of N supply (0, 50 and 100 mg N L^-1 fresh soil volume) under two levels of atmospheric O₃ concentration (< 5 and 60 ppb) for two growing seasons. Nitrogen treatment did not stimulate dry matter production of the seedlings. Growth inhibition was observed in the highest N treatment under low O₃ and in the two higher N treatments under elevated O₃. Irrespective of the O₃ concentration, increasing N supply negatively affected root growth and mycorrhizal development in fine roots, resulting in a reduction in P and Mg uptake from the soil. Net photosynthetic rate was significantly reduced by both the highest N treatment under low O₃ and the two higher N treatments under elevated O₃, together with decreased N-availability to Rubisco. Nitrogen assimilated from NO₃ ^- to amino acid in the needles was not affected by the treatments. However, needle protein concentration was reduced by the highest N-treatment under low O₃ and by the two higher N-treatments under elevated O₃. These results suggest that elevated O₃ potentially disturbs the N-availability in the form of protein including Rubisco, and may advance the negative effects of excessive N-deposition on N-sensitive plant species in N-saturated forests.     

Extraction and cleanup methods of dioxins in house dust from two cities in Japan using accelerated solvent extraction and a disposable multi-layer silica-gel cartridge

A simple and rapid method for the extraction and cleanup of dioxins from house dust was developed using an accelerated solvent extraction (ASE) method and a multi-layer silica-gel cartridge. It was found that the WHO-TEQ levels of dioxins extracted from the house dust obtained by both a conventional soxhlet extraction and the ASE were almost equal, when the data obtained by both methods were compared. As for the cleanup method, a multi-layer silica-gel cartridge yielded higher dioxin recoveries than the alkaline digestion method. The average values of the dioxins in house dust from Kumagaya city and Sendai city in Japan (Sendai city is bigger than Kumagaya city with respect to the population and industry), were 15.6 pg TEQ/g (8.6-26.0 pg TEQ/g, n=5, Kumagaya city) and 16.0 pg TEQ/g (5.9-30.5 pg TEQ/g, n=5, Sendai city), respectively.     

Model analysis of interactive effects of ozone and water stress on the yield of soybean

The interactive effects of ozone and water stress on the yield of soybean (Glycine max (L.) Merr. 'Davis') were addressed with a growth model of soybean. Two simulations were conducted, using the data from the exposures of soybean to ozone in open-top chambers under two soil moisture regimes, and the results of the simulations were compared. In the original simulation, soil moisture content was calculated based on a water budget using the actual precipitation and irrigation data. In the modified simulation, the soil water content was given as input data. In this case, soil moisture content was maintained at the same level across the ozone treatments regardless of different water use by the plants. Both simulations included the effect of reduced ozone flux to the leaves due to water stress, whereas only the original simulation included the effect of mitigated water stress due to reduced water use by the plants under higher ozone concentration. The water stress reduced ozone impact on soybean yield in the original simulation on the basis of the ozone dosecrop yield response relationship, but not in the modified simulation. The ozone uptake rate was reduced by water stress in the original simulation, but the relationship between seasonal mean ozone uptake rate and relative yield still showed reduced impact of ozone due to water stress. These results indicated that the alleviation of water stress by ozone due to reduced plant water use in ozone-treated plots can be a contributing factor in the reduction of ozone impact by water stress. The above conclusion was partly confirmed by the actual data for soil water content, which was significantly lower in the lowest ozone treatment than in the higher ozone treatments. Further experimental and modelling studies are needed to elucidate the mechanism of the ozone X water stress interaction.     

Respiratory uptake kinetics of neutral hydrophobic organic chemicals in a marine benthic fish, Pseudopleuronectes yokohamae

We investigated the respiratory uptake kinetics of polychlorinated biphenyls (PCBs), organohalogen pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and 2,2′,4,4′-tetrabrominated diphenyl ether (BDE #47) in a marine benthic fish, Pseudopleuronectes yokohamae. The respiratory uptake efficiencies (E_W) of the chemicals, of which there have been no reports for the majority of persistent organic pollutants (POPs), were obtained by measuring the respiratory uptake rate constants (k₁) and the oxygen consumption rates of fish. Fish were exposed to water in which these chemicals were dissolved at environmentally relevant concentrations for 28 d, followed by 168 d of depuration in clean seawater. The k₁ and E_W values for 99 compounds were obtained, and they ranged from 2000 to 42 000 L kg-lipid⁻¹ d⁻¹ and from 0.060 to 1.3, respectively. The E_W values of the chemicals, except for PAHs, tended to increase with increasing values of the log octanol–water partition coefficients (K_OW) of the chemicals up to a log K_OW of 5. For log K_OW in the range 3–5, the E_W values in this study were much lower than those in a published study (about one-third). As a result of analysis by a two-phase resistance model, the resistance of transport rates to the lipid phase in this study was lower than was the case in the published study. These findings indicate that the E_W predicted by the published study for log K_OW in the range 3–5 may differ among fish species and water temperature, and further study is needed.     

Sedimentation and remobilization of radiocesium in the coastal area of Ibaraki, 70 km south of the Fukushima Dai-ichi Nuclear Power Plant

Sedimentation and remobilization processes of radiocesium were investigated from time-series observations at nine stations in the coastal area of Ibaraki, 70–110 km south of the Fukushima Dai-ichi Nuclear Power Plant (1FNPP). Sediment samples were collected four times between June 2011 and January 2012, and concentrations of radiocesium as well as sediment properties such as grain size and elemental compositions were analyzed. Cumulative inventory of ¹³⁷Cs in sediment (0–10 cm) ranged between 4?×?10³ and 3?×?10⁴ Bq/m² as of January 2012. This amount was generally higher at stations nearer 1FNPP and has remained at the same level since August 2011. From these results, it can be inferred that dissolved radiocesium advected southward from the region adjacent to the 1FNPP and was deposited to the sediment of the study area in the early stage after the accident. The incorporation of radiocesium into sediments was almost irreversible, and higher concentrations of ¹³⁷Cs were obtained from the finer-grained fraction of sediments. In the northern offshore stations, resuspension of the fine-grained sediments formed a high-turbidity layer 10–20 m above the seabed. These results indicate that radiocesium-enriched fine particles were transported from the coast to offshore regions through the bottom high-turbidity layer.     

Comparison of arsenic uptake ability of barnyard grass and rice species for arsenic phytoremediation

In this research, the relative performance in arsenic (As) remediation was evaluated among some barnyard grass and rice species under hydroponic conditions. To this end, four barnyard grass varieties and two rice species were selected and tested for their remediation potential of arsenic. The plants were grown for 2 weeks in As-rich solutions up to 10 mg As L^?1 to measure their tolerance to As and their uptake capabilities. Among the varieties of plants tested in all treatment types, BR-29 rice absorbed the highest amount of As in the root, while Nipponbare translocated the maximum amount of As in the shoot. Himetainubie barnyard grass produced the highest biomass, irrespective of the quantity of As in the solution. In all As-treated solutions, the maximum uptake of As was found in BR-29 followed by Choto shama and Himetainubie. In contrast, while the bioaccumulation factor was found to be the highest in Nipponbare followed by BR-29 and Himetainubie. The results suggest that both Choto shama and Himetainubie barnyard grass varieties should exhibit a great potential for As removal, while BR-29 and Nipponbare rice species are the best option for arsenic phytoremediation.