Use of two population metrics clarifies biodiversity dynamics in large-scale monitoring: the case of trees in Japanese old-growth forests

An alkaline comet assay and a micronucleus test were carried out on erythrocytes of the European chub, Squalius cephalus L., collected in spring and autumn in 2005 and 2006 at three sampling sites in River Sava, near Zagreb, Croatia. The results of comet assay showed the lowest genotoxic influence at the least polluted site, while higher DNA damage was observed at the polluted sites. Although the basal levels of DNA damage were elevated, a clear gradation of DNA damage was found due to pollution intensity in all sampling periods. The lowest cytogenetic damage as revealed by the micronucleus test (MNT) was observed as well at the least polluted site. High variations in MN frequency were observed between sampling periods, although the number of micronucleated erythrocytes was consistently the highest one at the polluted site. The comet assay as a biomarker of genotoxic effect exhibited higher sensitivity in discriminating the genotoxic capacity of studied polluted sites while the MNT was less sensitive. However, both tests should be used together in biomonitoring studies because they can reveal different aspects of DNA damage; comet assay, the early event of genotoxic exposure, and MNT, its final result as a mutagenic potential.     

Effects of Long-Term Ungulate Exclusion and Recent Alien Species Control on the Preservation and Restoration of a Hawaiian Tropical Dry Forest

Abstract: Although the destruction of tropical rain forests receives much attention, tropical dry forests are in general far more threatened and endangered. Eliminating grazing ungulates is often considered a key first step toward protecting these ecosystems, but few studies have investigated the long-term effects of this technique. We examined the effects of ungulate exclusion from a 2.3-ha native dry-forest preserve on the island of Hawaii by comparing its present flora to the flora of an adjacent area subjected to continuous grazing since the preserve was fenced over 40 years ago. Relative to this adjacent area, the fenced preserve contained a more diverse flora with substantially greater coverage of native overstory and understory species. Until recently, however, regeneration of native canopy trees within the preserve appears to have been thwarted by a dominant herbaceous cover of alien fountain grass (   Pennisetum setaceum ) and predation by alien rodent species. Our results indicate that although ungulate exclusion may be a necessary and critical first step, it is not sufficient to adequately preserve and maintain Hawaii's remaining tropical dry forest remnants. Our recent efforts to control the dominant alien species within the fenced preserve suggest that this practice may facilitate both the regeneration of native species and the colonization and potential invasion of new alien plants. Comparisons of seedlings of the dominant native canopy tree Diospyros sandwicensis growing in sites both dominated by and free of fountain grass suggested that fountain grass inhibits Diospyros seedling growth and photosynthesis but may increase survival if seedlings are protected from ungulates.     

Degradation pathways of decabromodiphenyl ether during hydrothermal treatment

The hydrothermal degradation pathways of decabromodiphenyl ether during hydrothermal treatment were investigated. After an initial "Heating time", the reaction runs were carried out at constant temperature (heating to 300 degrees C and keeping temperature) and pressure (8MPa) in a SUS316 stainless steel micro autoclave filled with water. Some decomposition of decabromodiphenyl ether was observed over 200 degrees C, and it was decomposed by more than 99% after 10 min at 300 degrees C. The reactivities of bromine on para and meta substituents were relatively high, while its reactivity on ortho bromine was extremely low. The formations of polybrominated dibenzo-p-dioxins and furans (PBDD/DFs) were observed in the early stages of the reactions at around 300 degrees C. The TCDD toxicity equivalency (TCDD-EQs) of the by-products was determined based on relative potencies (REPs EC(5TCDD)) with the Dioxin-Responsive-Chemical Activated Luciferase gene eXpression (DR-CALUX) bioassays technology. These results indicated that the risk of formation of PBDD/DFs in the hydrothermal degradation of deca-BDE was low, and it would be possible to reduce the TCDD-EQs value by adding some catalyst or alkali, or extending processing time.     

Evaluation of thermally treated asbestos based on fiber number concentration determined by transmission electron microscopy

Appropriate treatment of asbestos waste is a significant problem. In Japan, inertization of asbestos-containing waste by novel techniques approved by the Ministry of the Environment is now promoted. A quantitative method of testing with high sensitivity to the asbestos levels present in the inertization products is required for the approval process, but many testing methods are only qualitative. Thus, we have developed an evaluation method for asbestos in inertized products, consisting of the extraction of fibers from inertized products and determination of fiber number concentration by transmission electron microscopy. We adopted this testing method to evaluate thermally treated asbestos. It was found that fiber number concentrations of thermally treated asbestos decreased with increased treatment temperature, and were below the environmental level (10² Mf/g) at more than 1000 °C for chrysotile and crocidolite and more than 1400 °C for amosite and other amphibole forms of asbestos.     

Spatiotemporal variability in recruitment around Iriomote Island, Ryukyu Archipelago, Japan: implications for dispersal of spawning corals

Spatiotemporal recruitment patterns of scleractinian corals were investigated around Iriomote Island, Ryukyu Archipelago, Japan, in relation to adult coral cover in 2005 and 2006. Although almost all corals were broadcasting spawners, the relationship between recruitment and adult coral cover differed among coral families (Acroporidae, Poritidae, and Pocilloporidae), likely due to differences in embryonic development time. For spawning pocilloporid corals, whose larvae develop relatively more rapidly, recruitment was higher at sites where adult coral cover was higher. In contrast, recruitment was not related to adult coral cover in acroporid and poritid corals, whose embryonic development times were relatively slow. Moreover, recruitment of acroporid corals varied between years, and recruitment was greater at leeward compared to windward reefs for a few days after spawning. These results suggest that embryonic development time and wind-driven surface currents affect larval dispersal and subsequent recruitment patterns at a local scale. Based on embryonic development time, some spawning corals are more likely to have higher rates of self-seeding than others. Our results predict that among spawning corals, local populations of acroporid and poritid corals, whose larvae potentially disperse over long distances and recruit in neighboring reefs, are more resilient to local disturbances than those of pocilloporid corals, whose recruitment relies upon local stock.     

Emission inventory of deca-brominated diphenyl ether (DBDE) in Japan

Atmospheric emissions of deca-brominated diphenyl ether (DBDE) in Japan were estimated based on the material flow of DBDE products and their emission factors. In 2002, the demand for DBDE in Japan was 2200 ton/year and the stock level was about 60 000 ton. The DBDE flow into the waste stream was estimated to be about 6000 ton/year and the flow out through second-hand product exports was more than 700 ton/year. Home appliance recycling facilities dismantle and crush domestic wastes containing about 600 ton of DBDE annually. Material recycling of crushed plastics is not commonly practiced as yet. Emission factors from plastics processing (2 × 10⁻⁹–1 × 10⁻⁷), textile processing (9 × 10⁻⁷), home appliance recycling (8 × 10⁻⁹–5 × 10⁻⁶), and waste incineration (1 × 10⁻⁷–2 × 10⁻⁶) were estimated using field measurement data. The DBDE emission rate through house dust during the service life of final products (2 × 10⁻⁷–9 × 10⁻⁷ per year) was estimated using the DBDE concentration in dust and the amount of dust in used televisions. Emission factors from previous studies were also used. The estimated total DBDE emission was 170–1800 kg/year. These results suggest the necessity of characterizing emissions during the service life of products, which is essential information for formulating an appropriate e-waste recycling strategy.     

Effect of phosphorus fluctuation caused by river water dilution in eutrophic lake on competition between blue-green alga Microcystis aeruginosa and diatom Cyclotella sp.

Tega-numa (Lake Tega) is one of the eutrophic lakes in Japan. For the improvement of water quality in Lake Tega, the Northchiba Water Conveyance Channel was constructed in 2000, which transfer water from Tone River into the lake. After 2000, the dominant species of diatoms, mainly Cyclotella sp., have been replacing blue-green algae, mainly Microcystis aeruginosa in Lake Tega. This transition of dominant species would be due to the dilution, but the detail mechanism has not been understood yet. This study examined the relationship between phosphorus fluctuation caused by river water dilution to Lake Tega and dominance of algal species, M. aeruginosa or Cyclotella sp. based on the single-species and the mixed-species culture experiments. The single-species culture experiment showed that the half-saturation constant and uptake rate of phosphorus were one order lower and seven times higher for M. aeruginosa than those for Cyclotella sp. These findings implied that M. aeruginosa would possess a potential for the growth and survival over Cyclotella sp. in the phosphorus limited condition. The superiority of M. aeruginosa was reflected in the outcome of the mixed-species culture experiment, i.e., dominance of M. aeruginosa, even phosphorus concentration was lowered to 0.01 mg-P/L. Therefore, it could be concluded that the decrease in phosphorus concentration due to the river water dilution to Lake Tega would be interpreted as a minor factor for the transition of dominant species from M. aeruginosa to Cyclotella sp.     

Leaching of brominated flame retardants in leachate from landfills in Japan

Leachate samples were taken from seven different landfills and concentrations of brominated flame retardants (BFRs), i.e. polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA), were quantified. Leaching characteristics of BFRs, especially factors affecting leachability, were clarified to obtain basic information regarding the release of BFRs into the environment. The results obtained for observed levels of the sum of PBDE-47, -99 and -100 were n.d.--4000 pg/l for the raw leachate and n.d. for the treated one, respectively, and those of TBBPA were n.d.--620,000 pg/l for the raw leachate and n.d.--11,000 pg/l for the treated one, respectively. Three sites that not only had crushed material from bulk wastes such as waste electric and electronic equipment, but also were under operation or within a year since closure, indicated a higher concentration of BFRs than the other sites. In particular extremely high concentration of PBDEs was observed at a site with a large amount of organics. Considering the leaching characteristics of BFRs, there exists the possibility that leachability of PBDEs is influenced by the presence of dissolved humic matter (DHM) in the leachate. The high removal efficiency for BFRs in the leachate treatment process was also confirmed.     

Metallic-phase lead in slag of municipal solid waste incineration ash and leaching characteristics

Metallic phases in slags and their influence on the leaching characteristics were investigated. The proportions of metallic phase in four slags were 0.028%, 0.24%, 1.87%, and 3.05% by weight. The lead content was 10–248 mg/kg in bulk slag after metal removal, while in the metallic phase it was 579–7390 mg/kg. Lead concentrations in the metallic phase were more than ten times higher than in slags after metal removal. Lead was distributed in the metallic phase at 2.0%, 8.3%, 10.3%, and 47.4%. The concentrations of all metallic elements in metallic phases were much higher than in bulk slag. Iron, copper, and nickel had accumulated in magnetic metals, while aluminum and zinc were found in nonmagnetic metals. As regards chromium, manganese, lead, and tin, the proportion of metallic phases depended on the slag samples. By removing metallic phases, both water and pH 4 leachable lead decreased. The basic principles of melting residues containing lead are the separation of lead as a metal in reductive melting, and the containment of lead ions into uniform glassy particles in oxidization melting. Melting slag can be seen to contribute to environmental preservation by facilitating the recycling of materials through the separation of metals from melting slag. Received: February 21, 2000 / Accepted: July 27, 2000     

Combinatorial bio/chemical analysis of dioxin and dioxin-like compounds in waste recycling, feed/food, humans/wildlife and the environment.

The present review describes international activities using bioassays/biomarkers in combination with chemical analysis to measure the effects of dioxin and dioxin-like compounds (DLCs) in the environment. The above authors reviewed already the state-of-art bioanalytical detection methods (BDMs) for dioxins and DLCs [Environ Int (2001)]. The aim of this study will be to review applications of these bioassays/biomarkers to evaluate potential dioxins and DLCs. The present literature study lists relative potencies (REPs) of polyhalogenated dibenzo-p-dioxins and -furans (PXDD/Fs; X = Cl, Br, F), their thio analogues polychlorinated dibenzothiophenes (PCDTs) and thianthrens (PCTAs), polyhalogenated biphenyls (PXBs), polychlorinated naphthalenes (PCNs) and other Ah receptor agonists measured by several biodetectors (Tier 3 screening). The authors will discuss some examples of the applications of some of these biodetectors in biomonitoring programmes and recently occurred dioxin crisis in feed/food. The diagnosis of the biopotency of these pollutants in technical processes like thermally treated waste, waste water treatment, landfill leachate treatment, commercial PCB-mixtures, the release into the environment (soil, air and water) and the final intake into wildlife and humans will be reviewed.