Concentration and distribution of dioxins and related compounds in human tissues

Polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran and dioxin-like polychlorinated biphenyl concentrations in human blood, lung, liver, bile, pancreas, spleen, kidney and mesentery fat were determined to assess the concentrations and distribution of these chemicals in human tissues from 20 donors. The mean TEQ concentrations in blood, lung, liver, bile, spleen, pancreas, kidney and mesentery fat were 119, 178, 228, 50, 113, 163, 138 and 139 pg TEQ/g lipid, respectively. Parallel levels were seen in the blood, spleen, kidney and mesentery fat; in the lungs and pancreas, the levels were somewhat higher. Among the organ tissues samples, the highest concentration was observed in the liver and the lowest in the bile. Mean total-TEQ concentration of the liver was about 4.5 times higher than that of bile. Positive correlations were observed among the concentrations of dioxins in various tissues. However, the concentrations in bile were not correlated with any tissues. It is suggested that the distribution behavior of dioxin-like congeners in human tissues varies among tissues and the kinds of congeners ingested. To evaluate the relationship between the accumulation levels of dioxins and their pathophysiological significance or risk, data must be accumulated from a more extensive group of human samples.     

Toxicological evaluation of the chemical oxidation methods for landfill stabilization

As the stabilization criteria for landfill sites, only chemical criteria for the leachate discharges from the landfill sites have been used in Japan and many other countries. Recently, chemical oxidation has been developed as a method for the early-stabilization of landfills. However, by-products that are difficult to detect by chemical analysis can be produced by this method. Therefore, toxicity tests are useful tools for detecting the changes of leachate quality after application of this method. The heat source in the A landfill was analyzed by organic position inquiry technology, and ozone-treated leachate was sprayed back to the heat source in the landfill. Toxicity changes of the leachate after the spray were monitored using Microtoxtrade mark, ToxScreen-II, and DaphTox tests. The hardly-degradable organic matter was efficiently removed and toxicities of the leachate in the heat source decreased after the application. These toxicity results were significantly related to chemical oxygen demand (COD) changes. Thus, it was concluded that the toxicity tests were effective for monitoring the leachate quality after applying the chemical oxidation method for landfill stabilization, and its incorporation to establish the criteria for early-stabilization of landfill sites needs to be considered.     

A method for diagnosis of plant environmental stresses by gene expression profiling using a cDNA macroarray

Plants in the field are subjected to numerous environmental stresses. Lengthy continuation of such environmental stresses or a rapid increase in their intensity is harmful to vegetation. Assessments of the phytotoxicity of various stresses have been performed in many countries, although they have largely been based on estimates of leaf injury. We developed a novel method of detecting plant stresses that is more sensitive and specific than those previously available. This method is based on the detection of mRNA expression changes in 205 ozone-responsive Arabidopsis expressed sequence tags (ESTs) by cDNA macroarray analysis. By using this method, we illustrated shifts in gene expression in response to stressors such as drought, salinity, UV-B, low temperature, high temperature, and acid rain, as distinct from those in response to ozone. We also made a mini-scale macroarray with 12 ESTs for diagnosis of the above environmental stresses in plants. These results illustrate the potential of our cDNA macroarray for diagnosis of various stresses in plants.     

How is a giant sperm ejaculated? Anatomy and function of the sperm pump, or “Zenker organ,” in Pseudocandona marchica (Crustacea, Ostracoda, Candonidae)

‘Giant sperm’, in terms of exceptionally long spermatozoa, occur in a variety of taxa in the animal kingdom, predominantly in arthropod groups, but also in flatworms, mollusks, and others. In some freshwater ostracods (Cypridoidea), filamentous sperm cells reach up to ten times the animal’s body length; nonetheless, during a single copulation several dozen sperm cells can be transferred to the female’s seminal receptacle. This highly effective ejaculation has traditionally been credited to a chitinous-muscular structure within the seminal duct, which has been interpreted as a sperm pump. We investigated this organ, also known as the Zenker organ, of a cypridoid ostracod, Pseudocandona marchica, utilizing light and electron microscope techniques and produced a three-dimensional reconstruction based on serial semi-thin histological sections. This paper shows that numerous muscle fibers surround the central tube of the Zenker organ, running in parallel with the central tube and that a thin cellular layer underlies the muscular layer. A cellular inner tube exists inside the central tube. A chitinous-cellular structure at the entrance of the organ has been recognized as an ejaculatory valve. In male specimens during copulation, we confirmed a small hole derived from the passage of a single spermatozoon through the valve. The new data allowed for proposing a detailed course of operation of the Zenker organ during giant sperm ejaculation.     

Visual determination of nitrite and nitrate in waters by color band formation method

A spot test for aqueous nitrate and nitrite for controlling nitrogen removal performance in small-scale wastewater treatment facilities is proposed. In this method, NO(2)(-) ion in water samples was allowed to react with sulfanilic acid and 1-naphthol to form an anionic azo dye. The resulting colored solution was introduced onto a mini column (similar to a gas detecting tube) packed with PVC particles coated with benzyl cetyl dimethyl ammonium chloride (BCDMA) and biphenyl. The NO(2)(-)-N concentration was determined visually by measuring the color band length (CBL) in the column. The CBL correlates linearly with nitrite concentration in the 4-20 mg-N l(-1) range. The concentration of nitrite+nitrate was determined after reduction to nitrite with zinc. The concentration of NO(3)(-)-N species was calculated by difference. This method was used to visually determine the concentrations of NO(2)(-)-N and (NO(2)(-)+NO(3)(-))-N in domestic wastewater samples with maximum suspended solid (SS) and chemical oxygen demand (COD) concentrations of 114 mg l(-1) and 73.9 mg l(-1), respectively.     

Biodegradation of Chitosan-Gellan and Poly(L-lysine)-Gellan Polyion Complex Fibers by Pure Cultures of Soil Filamentous Fungi

The degradation of two kinds of polyion complex (PIC) fibers, chitosan-gellan (CGF), and poly(L-lysine)-gellan (LGF) fibers, by seven species of soil filamentous fungi has been investigated. All of the pure-line soil filamentous fungi, Aspergillus oryzae, Penicillium caseicolum, P. citrinum, Mucor sp., Rhizopus sp., Curvularia sp., and Cladosporium sp. grew on the two fiber materials. Microscopic observation of the biodegradation processes revealed that P. caseicolum on the CGF and LGF grew, along with the accompanying collapse of the fiber matrices. In the biochemical oxygen-demand (BOD) test, the biodegradation of the LGF by P. caseicolum and Curvularia sp. exceeded 97% carbon dioxide generation and the biodegradation of the CGF by A. oryzae was 59%. These results might offer some clues to the applications of the PIC fibers as environmentally biodegradable materials.     

Japan’s greenhouse gas reduction scenarios toward net zero by 2050 in the material cycles and waste management sector

The first draft scenario toward net zero greenhouse gas (GHG) emissions by 2050 for the material cycles and waste management sector was presented by the Ministry of the Environment, Japan in August 2021. The details of the future GHG emission estimation used to create the draft scenario are described in this document. For multiple scenarios where more aggressive measures, such as carbon capture, utilization, and storage (CCUS), were included in addition to business-as-usual and the current policy continuity scenario, future GHG emissions were estimated as the sum of the products of activities and emission factors indicating changes in measures between scenarios. The estimation outcomes demonstrated that future GHG emissions from the solid waste management sector could be anticipated to be zero or even negative when material conversion to biomass, primarily for plastics, recycling to raw materials, and installation of CCUS at incineration facilities are assumed. Extensions of prior plans are not enough to reach the goal of net zero emissions, according to the measures necessary and the volume and pace of their implementation suggested in this study. Stakeholders should collaborate with great ambition.