A level change in mutagenicity of Japanese tap water over the past 12 yr

A relative comparison study of mutagenicity in Japanese tap water was conducted for 1993 and 2005 surveys. It intended to assess the effects of advanced water treatment installations to water works, improvement of raw water quality and improvement of residual HOCl concentration controlling. Sampling points (taps) were the same in both surveys. The results of 245 samples obtained by the Ames Salmonella mutagenicity test (Ames test) were analyzed. The Ames tests were conducted by using Salmonella typhimurium TA98 and TA100 strains with and without exogenous activation (S9). With the exception of TA100-S9, the other conditions needed no discussion as a factor in the mutagenicity level change. The average mutagenicity in 1993 and 2005 under the conditions of TA100-S9 were 2600 and 1100 net revertant L⁻¹, respectively. This indicated that the mutagenicity level of Japanese tap water decreased during the 12-yr period. Particularly a remarkable decrease in mutagenicity was observed in the water works where the advanced water treatments were installed during the 12-yr period. The advanced water treatments were effective in decreasing the mutagenicity of tap water. Mutagenicity also decreased in the water works with conventional water treatments; the improvement of residual HOCl concentration controlling was also considered to be effective in decreasing the mutagenicity of tap water.     

Female sex pheromone of Ostrinia orientalis – throwing a light on the relationship between O. orientalis and the European corn borer, O. nubilalis

Summary. The sex pheromone of Ostrinia orientalis (Lepidoptera: Crambidae) was analyzed by gas chromatography–electroantennographic detection (GC–EAD), GC–mass spectrometry and a series of bioassays. Three EAD-active compounds were detected in the female sex pheromone gland extract, and identified as tetradecyl acetate (14:OAc), (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (E)-11-tetradecenyl acetate (E11-14:OAc). The titers (ratio) of 14:OAc, Z11-14:OAc and E11-14:OAc in 3-day-old virgin females were 0.49 ng (10), 4.86 ng (98) and 0.10 ng (2), respectively. In a wind-tunnel bioassay, the 98:2 blend of Z11- and E11-14:OAc, but not Z11-14:OAc alone, elicited the same male behavioral responses as virgin females and crude gland extracts. 14:OAc was inactive by itself, and did not show any synergistic effect on the binary blend. Field trapping experiments also confirmed the attractiveness of the binary blend to O. orientalis males. Based on these results, we concluded that the sex pheromone of O. orientalis is a 98:2 mixture of Z11-14:OAc and E11-14:OAc. This sex pheromone is very similar to that of the Z-type European corn borer, O. nubilalis. The present finding raises the question of whether O. orientalis , which is indistinguishable from O. nubilalis based on external morphology, is a biologically distinct species independent from O. nubilalis.     

Detection of Rotavirus Strains in Freshwater Clams in Japan

Bivalve molluscan shellfish like clams and oysters, etc., are capable to bioaccumulate surrounding contaminants from waters into their digestive systems and posing serious threats of food poisoning. Detection of rotaviruses (RVs) in shellfish is of particular importance because RVs are prone to genome reassortment resulting in the emergence of new RV variants that may compromise vaccine safety. Herein, we have detected the wild-type RVs and Rotarix/RotaTeq vaccine strains in freshwater clams collected on the riverside, Kawasaki city, from July 2019 to January 2020 and correlated the detected genotypes with that of gastroenteritis cases of nearby clinics to understand the transmission of RVs in the environment. The wild-type RVs were detected in 62 (64.6%) out of 96 freshwater clams in every study month: July, September, November, and January that are considered as off-season for RV infections. The most frequent genotypes were G2 (42.9%), G8 (28.6%), G3 (14.3%), G1 (7.1%), and G10 (7.1%), which remained comparable with genotypic distribution found in the clinical samples over the last few years indicating that these RVs may accumulate in clams since a long time. However, G10 genotype was detected in clam but not in clinical samples suggesting the presence of asymptomatic infection or RVs could be carried out from a long distance. Importantly, vaccine strains, RotaTeq (1%) but not Rotarix (0%), were also detected in a clam. Attention must be paid to monitoring the potential transmission of wild-type and vaccine RV strains in the environment to prevent the emergence of new variants generated from genome reassortment with vaccine strains.

     

Evaluating waste disposal systems

Waste disposal systems conventionally exhibit many problems, such as difficulties in finding final disposal sites for incinerator residues and the issue of how to recycle waste materials. Some new technologies have been developed to solve such problems, including ash melting and gasification melting. Furthermore, to improve the power generation efficiency of waste treatment facilities so that their energy is used more efficiently, combined stoker/gas turbine power generation (super waste power generation) technology has been developed. Through examination of two cases in this study, environmental impacts and costs were determined using lifecycle assessment (LCA) and lifecycle cost (LCC) methods in a model city. In case 1, a stoker furnace was compared to a combined stoker/gas turbine system. In case 2, a stoker furnace plus ash melting system was compared to a gasification melting system. The results demonstrate that the stoker furnace has a lower environmental impact than the combined stoker/gas turbine system in case 1, and that the stoker plus ash melting system costs less than the gasification melting system in case 2, but both systems had strong impacts on the environment.     

Formaldehyde Exposure in a Gross Anatomy Laboratory. Personal Exposure Level Is Higher Than Indoor Concentration (5 pp)

Goal, Scope and Background Cadavers for gross anatomy laboratories are usually prepared by using embalming fluid which contains formaldehyde (FA) as a principal component. During the process of dissection, FA vapors are emitted from the cadavers, resulting in the exposure of medical students and their instructors to elevated levels of FA in the laboratory. The American Conference of Governmental Industrial Hygienists (ACGIH) has set a ceiling limit for FA at 0.3 ppm. In Japan, the Ministry of Health, Labour and Welfare has set an air quality guideline defining two limit values for environmental exposure to FA: 0.08 ppm as an average for general workplaces and 0.25 ppm for specific workplaces such as an FA factory. Although there are many reports on indoor FA concentrations in gross anatomy laboratories, only a few reports have described personal FA exposure levels. The purpose of the present study was to clarify personal exposure levels as well as indoor FA concentrations in our laboratory in order to investigate the relationship between them. Methods The gross anatomy laboratory was evaluated in the 4th, 10th and 18th sessions of 20 laboratory sessions in total over a period of 10 weeks. Air samples were collected using a diffusive sampling device for organic carbonyl compounds. Area samples were taken in the center and four corners of the laboratory during the entire time of each session (4-6 hours). Personal samples were collected from instructors and students using a sampling device pinned on each person's lapel, and they were 1.1 to 6 hours in duration. Analysis was carried out using high performance liquid chromatography. Results and Discussion Room averages of FA concentrations were 0.45, 0.38 and 0.68 ppm for the 4th, 10th and 18th sessions, respectively, ranging from 0.23 to 1.03 ppm. These levels were comparable to or relatively lower than the levels reported previously, but were still higher than the guideline limit for specific workplaces in Japan and the ACGIH ceiling limit. The indoor FA concentrations varied depending on the contents of laboratory sessions and seemed to increase when body cavity or deep structures were being dissected. In all sessions but the 4th, FA levels at the center of the room were higher than those in the corners. This might be related to the arrangement of air supply diffusers and return grills. However, it cannot be ruled out that FA levels in the corners were lowered by leakage of FA through the doors and windows. Average personal exposure levels were 0.80, 0.45 and 0.51 ppm for instructors and 1.02, 1.08 and 0.89 ppm for students for the 4th, 10th and 18th session, respectively. The exposure levels of students were significantly higher than the mean indoor FA concentrations in the 4th and 10th sessions, and the same tendency was also observed in the 18th session. The personal exposure level of instructors was also significantly higher than the indoor FA level in the 4th session, while they were almost the same in the 10th and 18th sessions. Differences in behavior during the sessions might reflect the differential personal exposure levels between students and instructors. Conclusion The present study revealed that, if a person is close to the cadavers during the gross anatomy laboratory, his/her personal exposure level is possibly 2 to 3-fold higher than the mean indoor FA concentration. This should be considered in the risk assessment of FA in gross anatomy laboratories. Recommendation and Outlook If the risk of FA in gross anatomy laboratories is assessed based on the indoor FA levels, the possibility that personal exposure levels are 2 to 3-fold higher than the mean indoor FA level should be taken into account. Otherwise, the risk should be assessed based on the personal exposure levels. However, it is hard to measure everyone's exposure level. Therefore, further studies are necessary to develop a method of personal exposure assessment from the indoor FA concentration.     

Vibratory communication in the soil: pupal signals deter larval intrusion in a group-living beetle <Emphasis Type="Italic">Trypoxylus dichotoma</Emphasis>

Pupae of several insect species are known to generate air-borne sounds and/or substrate-borne vibrations, but the functions of the sounds/vibrations are not well understood. Here, we present the first evidence of vibratory communication between pupae and larvae of a group-living Japanese rhinoceros beetle Trypoxylus dichotoma which inhabits humus soil. The last-instar larvae of this beetle construct their own pupal cells to ensure normal pupation and eclosion. These cells are fragile and subject to damage from burrowing larvae because pupae and larvae co-inhabit the same patches of humus. In laboratory experiments, we demonstrated that pupal cells harboring live pupae were less likely to be broken by larvae than those harboring dead pupae. It was also demonstrated that pupae produced vibrations in response to larvae approaching the pupal cells. High-speed video and vibration analyses showed that pupae emitted 3–7 pulses at 1.3-s intervals by beating their pronotum against the inner wall of the pupal cell. The pupal vibration was of low frequency with a maximum energy at ≈ 100 Hz. The drumming behavior was more frequently observed in the presence of an approaching larva than in its absence. When pupal vibrations were played back near to vacant artificial pupal cells, these cells were rarely disturbed by the larvae. These results provide evidence that pupae generate vibrations to deter conspecific larvae, thereby preventing damage to the cells. This larval response to pupal vibrations may have evolved through preexisting anti-predator and/or sib-killing-avoidance behavior.     

A sex pheromone component novel to Ostrinia identified from Ostrinia latipennis (Lepidoptera: Crambidae)

Summary. Extracts from the sex pheromone gland of Ostrinia latipennis (Lepidoptera: Crambidae) were analyzed by gas chromatography-electroantennographic detection (GC-EAD) and GC-mass spectrometry. Only an EAD-active compound was detected in the extract, and it was identified as (E)-11-tetradecenol (E11-14:OH). In a wind-tunnel bioassay, E11-14:OH elicited a series of mate finding behaviors from males, although it was far less active than virgin females and crude extract of the pheromone gland. The attractiveness of E11-14:OH to O. latipennis males was confirmed by field trapping experiments. Based on these findings, we concluded that E11-14:OH, which is novel to the genus Ostrinia, is a major component of the sex pheromone in O. latipennis. The significance of the use of alcohol in place of the usual acetates in Ostrinia is discussed in relation to the pheromone biosynthesis system. Received 9 December 1999; accepted 14 March 2000     

Evaluating household waste treatment systems with specific examination of collection and transportation processes

To form a sustainable recycling society, control industrial waste, and reutilize resources from waste to the greatest extent possible, we evaluated the waste collection system in terms of CO₂ emissions, the energy consumed, the amount recycled, the final disposal amount, and cost, particularly addressing the collection and transportation processes of domestic waste and using LCA evaluation for multiple policies. The results showed that enforcement of a combination of five optimal policies (as assessed in terms of their evaluation indexes), i.e., the use of clean energy gas-powered vehicles, the station method, collection of waste segregated into 11 categories, collective collection, and simple pay-as-you-go charges, might cultivate residents’ sense of responsibility in terms of controlling waste discharge.