Endocrine disrupter nonylphenol and bisphenol A contamination in Okinawa and Ishigaki Islands, Japan--within coral reefs and adjacent river mouths

Certain chemicals possess the potential to modulate endocrine systems, and thereby interfere with reproduction and developmental processes in the wild. We analyzed endocrine disrupters nonylphenol (NP) and bisphenol A (BPA) levels at various sites in Okinawa and Ishigaki Islands, Japan. River-water samples showed undetectable to low concentrations of NP and BPA at most of the sites investigated. However, an appreciable amount of BPA was detected in sediments at one coral reef site. In addition, significant numbers of river sediment samples showed appreciable amounts of NP and BPA. Most of the sampling sites for this study are located within a distance of 1 km from the coral reefs, which are under influence of river-waters to a variable extent. Therefore, influence of endocrine disrupters may have already begun on adjacent coral reefs. Both endocrine disrupters were positively correlated with human population densities, but not with the contents of red soil generated by farm land reformation. Therefore, it is concluded that NP and BPA pollution is a consequence of human waste discharge, both domestic and industrial, and not by agricultural activities.     

Seasonality,lunar periodicity of settlement and microhabitat association of juvenile humpback red snapper <Emphasis Type="Italic">Lutjanus gibbus</Emphasis> (Lutjanidae) in an Okinawan coral reef

Snappers (Lutjanidae) are one of the important fisheries resources in tropical and subtropical waters. However, there have been few studies clarifying the ecology of newly settled juvenile snappers. The aims of the present study were to clarify the seasonality and lunar periodicity of the larval settlement, and the microhabitat association of newly settled juveniles for Lutjanus gibbus in an Okinawan coral reef. Fifteen coral patches were chosen and underwater visual surveys were conducted during a 2-year period. The larval settlement of the species mainly occurred between May and October during the 2-year survey period. In terms of lunar periodicity of the settlement, the newly settled juveniles were mainly found between the last quarter moon and new moon during the main settlement season. Back calculations of settlement dates based on otolith microstructure showed that most juveniles settled during the last quarter moon and new moon. Stepwise multiple regression analyses revealed that the newly settled juveniles were mainly found on coral patches with a large number of holes on the top of the coral patch and this tendency was mainly consistent during the study period. The volume of holes at the base of coral patches had also a positive effect on the abundance of newly settled juveniles in some cases. The results of the present study suggest that larval settlement has a strong seasonal and lunar periodicity, and newly settled juveniles select coral patches with available refuge spaces.     

An overlooked side effect of nest-scattering behavior to decrease predation risk (Acari: Tetranychidae,Stigmaeidae)

The number of nests containing egg masses a female makes over her lifetime and the pattern of scattering nests vary among species in a genus of nest-weaving spider mites (Stigmaeopsis). We hypothesized that the scattered nests of small nest builders have a previously overlooked indirect effect in that the void nests created after predation take on a new role as hindering devices that effectively decrease predator searching efficiency. First, we demonstrated that the experimental design used in this study is a good reflection of the nest distribution pattern of Stigmaeopsis takahashii (an intermediate-sized nest builder) in the field. Using this species as a model, we tested how different nest-scattering patterns affect the predator to examine how scattering may indirectly provide an anti-predation strategy by increasing a predators searching time. Next, we observed how artificially arranged void nests disturb predatory behavior in both starved and fully fed predator females and showed that void nests have a strong hindering effect on predators. Thus, we concluded that the nesting behavior of this mite species not only has anti-predator effects but must also have a stabilizing effect on predator–prey interaction systems at the population level.     

Environmental impact assessment of sprayed-on asbestos in buildings

This study evaluated the environmental impacts of sprayed-on asbestos, which had been used as insulation material in buildings, from multiple perspectives, mainly at the disposal stage. The health risks from asbestos emission and energy consumption were estimated. Two disposal scenarios were assumed for the asbestos: melting for reduced-risk disposal and ordinary packaging/landfilling. We estimated the asbestos emission and health risk in the case of packaging/landfilling, assuming uncontrolled management of the landfill site. A difficulty with introducing health-risk concepts into life cycle assessment (LCA) is the pulse–flux problem, which is discussed in the light of these estimations. In order to solve this problem, we proposed a method using a conversion factor representing exposure-dose/emission, and showed that emission could be converted into health risk. We also estimated the energy consumption for melting asbestos in the disposal stage, which can decrease the health risk. If we consider the energy consumption for the life cycle of asbestos, only a little energy is required for melting, compared with the large amount of energy saved in the use stage owing to the insulating effect of the asbestos. The trade-off relationship between health risk and energy consumption for the disposal scenarios indicated the need for weighting methods to handle trade-offs such as this. Received: July 2, 1998 / Accepted: December 20, 1999     

Analysis of branched-chain fatty acids in humic substances as indices for compost maturity by pyrolysis–gas chromatography/mass spectrometry with tetramethylammonium hydroxide (TMAH-py–GC/MS)

Parameters that affect the degree of humification for humic substances (HSs) are deeply related to the maturity of the compost. In general, the matured composts contain HSs with a higher degree of humification. In addition, microbial activities during composting are also one of the indices for compost maturation. Branched-chain fatty acids are metabolites as the result of microbial activities in a soil environment. Such branched-chain fatty acids, regarded as humic precursors, are incorporated into HSs during the composting process. To determine whether branched-chain fatty acids in HSs can be used as biomarkers during composting processes or not, HSs were extracted from three types of composts with the different maturation, and the branched-chain fatty acids in the HSs were analyzed by pyrolysis–gas chromatography/mass spectrometry with tetramethylammonium hydroxide (TMAH-py–GC/MS). HSs with a higher degree of humification (higher aromaticity and lower molecular weight) contained higher levels of branched-chain fatty acids. These results show that branched-chain fatty acids in HSs from matured compost samples can be used as biomarkers, which indicate the history of microbial activities during overall composting process.     

Development of a testing method for asbestos fibers in treated materials of asbestos containing wastes by transmission electron microscopy

Appropriate treatment of asbestos-containing wastes is a significant problem. In Japan, the inertization of asbestos-containing wastes based on new treatment processes approved by the Minister of the Environment is promoted. A highly sensitive method for testing asbestos fibers in inertized materials is required so that these processes can be approved. We developed a method in which fibers from milled treated materials are extracted in water by shaking, and are counted and identified by transmission electron microscopy. Evaluation of this method by using asbestos standards and simulated slag samples confirmed that the quantitation limits are a few million fibers per gram and a few μg/g in a sample of 50 mg per filter. We used this method to assay asbestos fibers in slag samples produced by high-temperature melting of asbestos-containing wastes. Fiber concentrations were below the quantitation limit in all samples, and total fiber concentrations were determined as 47–170 × 10^?6 f/g. Because the evaluation of treated materials by TEM is difficult owing to the limited amount of sample observable, this testing method should be used in conjunction with bulk analytical methods for sure evaluation of treated materials.     

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solid electrode

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solidelectrode was studied. As solid electrodes, carbon cloth (CC), carbon felt (CF) and titanium mesh were used, and palladium was plated on solid electrodes by either electrolytic or electroless method. On each electrode with Pd, chlorophenols were qualitatively dechlorinated to phenol, while they were entirely intact on electrodes without Pd. Moreover, neither base electrode nor plating method significantly affected the activity of Pd as far as it was sufficiently loaded on the electrode. Based on the results in the experiments using one electrode repeatedly, Pd catalyst proved to possess a satisfactory duarability under the present condition. It was suggested that the reactive species responsinble for the dechlorination of chlorophenols could be formed during preliminary electrolysis. Thus, (Pd)_x-H resulting from the adsorption of electrogenerated hydrogen on metallic Pd might be assumed most probable.     

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solid electrode

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solidelectrode was studied. As solid electrodes, carbon cloth (CC), carbon felt (CF) and titanium mesh were used, and palladium was plated on solid electrodes by either electrolytic or electroless method. On each electrode with Pd, chlorophenols were qualitatively dechlorinated to phenol, while they were entirely intact on electrodes without Pd. Moreover, neither base electrode nor plating method significantly affected the activity of Pd as far as it was sufficiently loaded on the electrode. Based on the results in the experiments using one electrode repeatedly, Pd catalyst proved to possess a satisfactory duarability under the present condition. It was suggested that the reactive species responsinble for the dechlorination of chlorophenols could be formed during preliminary electrolysis. Thus, (Pd)_x-H resulting from the adsorption of electrogenerated hydrogen on metallic Pd might be assumed most probable.     

Electrostatic hazards of charging of bedclothes and ignition in medical facilities

We investigated the charge generated on bedclothes (cotton and polyester) during bedding exchange with different humidities and the ignitability of an alcohol-based hand sanitizer (72.3 mass% ethanol) due to static spark with different temperatures to identify the hazards of electrostatic shocks and ignitions occurring previously in medical facilities. The results indicated that charging of the polyester bedclothes may induce a human body potential of over about 10?kV, resulting in shocks even at a relative humidity of 50%, and a human body potential of higher than about 8?kV can cause a risk for the ignition of the hand sanitizer. The grounding of human bodies via footwear and flooring, therefore, is essential to avoid such hazards (or to reduce such risks).