Relationship of PCDD/F and Co-PCB concentrations in breast milk with infant birthweights in Tokyo, Japan

OBJECTIVE: To observe how PCDD/F and Co-PCB concentrations in breast milk relate to infant birthweights in Tokyo, Japan. STUDY DESIGN: Breast milk samples were collected from 240 mothers (aged 25-34years old) residing in Tokyo to measure the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs; 14 congeners), polychlorinated dibenzofurans (PCDFs; 15 congeners), and coplanar polychlorinated biphenyls (Co-PCBs; 12 congeners) in the breast milk fat. Individual milk samples (about 50ml) were obtained 30days after delivery, between the months of June and September in 1999 and 2000. The relationship of the infant birthweights with the PCDD/F and Co-PCB concentrations was observed. RESULTS: The birthweights were negatively correlated the concentrations of many of the PCDD/F and Co-PCB congeners, with the mean toxic equivalent quantities (TEQs) of the Co-PCBs, and with the sum of the PCDD, PCDF and Co-PCBs, although their correlation coefficients were less than 0.200. Multiple regression analysis showed octachlorodioxin was statistically significant explanatory variate. CONCLUSIONS: There were slight relationship between the dioxins levels of breast milk and the birthweights of the infants.     

Combustible and incombustible speciation of Cl and S in various components of municipal solid waste

Chlorine (Cl) and sulfur (S) in municipal solid waste (MSW) are important reactive elements during combustion. They generate the acidic pollutants HCl and SOx, and, furthermore, produce and suppress organic chlorinated compounds. Nevertheless, few practical reports about Cl and S content in MSW have been published. In combustion and recycling processes, both combustible Cl and S, and incombustible Cl and S species are equally important. This paper presents the results of a comprehensive study about combustible and incombustible Cl and S in MSW components, including kitchen garbage, paper, textiles, wood and leaves, plastics and small chips. By integrating this collected data with data about MSW composition, not only the overall content of Cl and S in MSW, but also the origins of both combustible and incombustible Cl and S were estimated. The average Cl content in bulk MSW was 3.7 g/kg of raw MSW, of which 2.7 and 1.0 g/kg were combustible and incombustible, respectively. The Cl contribution from plastics was 76% and 27% with respect to combustible and incombustible states. The average S content in bulk MSW was 0.81 g/kg of raw MSW, of which 0.46 g/kg was combustible and 0.35 g/kg was incombustible. Combustible S was mainly due to synthetic textiles, while incombustible S was primarily from paper.     

Shedding of gametes in the compound ascidian Botryllus primigenus

The shedding of gametes of Botryllus primigenus Oka occurs in the natural environment early in the morning, about 1 h after dawn. The shedding of the sperm from a testis is completed within a few seconds. All the spermatozoa in a testis are released at once. Ovulation begins about 10 min after shedding of sperm and is completed in about 1 min. In general, combinative testes, i.e., testes accompanied by egg follicles, macure first, followed by egg follicles, solitary testes located on the left side of the zooid, and finally those on the right side, in that order. As a result, a population of zooids of the same generation in a colony sheds sperm on 2 or 3 successive days. Illumination preceded by darkness effectively induces shedding of gametes experimentally. The required minimum dark-adaptation period is 40 min; the required minimum illumination period is dependent on light-intensity, 8, 4 and 1 min being required at 70, 200 and 3,000 lux, respectively; the latent period is temperature-dependent, 100 to 130, 70 to 90 and 50 to 60 min being required at 21^o, 26^o and 27.5°C, respectively. An experiment in which only part of the colony was illuminated clearly indicated that each zooid responds to light-stimulus independently.Contribution No. 306 from the Shimoda Marine Research Center, University of Tsukuba, Japan.     

The acute toxicity of arsenobetaine

The acute toxicity of arsenobetaine was studied in male mice. No deaths were observed with oral administration of 10 g/kg of arsenobetaine. Therefore the LD₅₀ value was higher than 10 g/kg. This compound was found in urine in the non-metabolized form. No particular toxic symptoms were observed following administration. These results suggest that arsenobetaine has low toxicity and is not metabolized in mice.     

The flame retardant tetrabromobisphenol-A and its metabolite found in river and marine sediments in Japan

Tetrabromobisphenol-A (TBBP), used as a flame retardant, was detected in river sediments collected in Osaka, Japan, at a concentration range from 22 to 140 μg/kg (ppb), as determined on a dry weight basis. TBBP was also found in marine sediments collected at Osaka Bay, though the TBBP levels of these samples were much lower than those from river sediments. Dimethyl ether derivative of TBBP (TBBP-DM), thought to be a decomposition product from microbial methylation, was found in the river sediments but in none of the marine sediments. TBBP-DM residues were about one-hundredth of the TBBP levels.     

A simple and convenient empirical survey method with a soil electrical conductivity meter for incineration residue-derived soil contamination

To facilitate field surveys for identifying areas of incineration residue-derived soil contamination, a simple and convenient method with a soil electrical conductivity meter was examined. First, the leaching test specified by Notification No. 13 of the Ministry of the Environment, 1973, was conducted on 506 samples of 11 types of wastes and compost, and the relationship between the concentrations of toxic elements [total Hg (T-Hg), Cd, Pb, Cr⁶⁺, and As] and values of electrical conductivity (EC) was examined. The results showed that bottom ash and fly ash were wastes with high EC values and that these wastes indicated higher levels of toxic elements. Second, an estimation method for the soil EC value of contaminated soil (ECc) was proposed based on the EC values of noncontaminated soil, and its usefulness was examined. The results of field surveys conducted at sites whose soils were suspected of contamination by dioxins and other pollutants derived from incineration residues showed that the contaminated spots and areas were identified by using ECc values. Moreover, comparison of the elemental contents of soils in terms of Cr, Ni, Zn, Na, K, Ca, Fe, Mn, and others, in addition to the above-mentioned toxic elements (excluding Cr⁶⁺), with those of the potential sources of pollution was verified to be effective for identifying the source of soil contamination.     

Biological effect on blood cerebrospinal fluid barrier due to radio frequency electromagnetic fields exposure of the rat brain in vivo

Concerns on health effects of radiofrequency (RF) signals have been discussed. Particularly, the effect on the central nerve system is one of main interest among the general public. So far, there are lots of studies regarding the RF effect on the Blood Brain Barrier (BBB), but no study of the RF effect on the Blood Cerebrospinal fluid Barrier (BCB). In this study we explored the effect on BCB function by radiofrequency electromagnetic fields (RF-EMF) exposure. To attain this purpose, we set about to make a real-time measuring system for BCB function using a micro-perfusion method and examined the short time exposure experiment using rats. Our data suggested the 30 min single exposure of 1.5 GHz RF-EMF at the brain average SARs of 9.5 W/kg for adult and 10.4 W/kg for juvenile, did not affect BCB function in rats under the experimental conditions.     

The choosing of sleeping position in the overnight aggregation by the solitary bees <Emphasis Type="Italic">Amegilla florea urens</Emphasis> in Iriomote Island of Japan

In addition to the process of joining the sleeping aggregation, the choice of sleeping position is an important night-time behaviour of small diurnal insects because of the increased risk for predator attacks as well as bad weather. The aggregation behaviour of the solitary bee Amegilla florea urens was investigated to elucidate the choice of sleeping position on substrates. Male and female constructed single-sex aggregations on hanging leaves during May and June, respectively. Most individuals tended to form aggregations with other individuals while few individuals slept alone. During the aggregation forming, both the number of individuals that tried to join the aggregation and the completion time of aggregation increased with the number of sleeping individuals, whereas the success rate of joining was unaffected. The sleeping positions of subsequent arrivals on the substrates were higher than those of the first arrivals in female aggregations. Therefore, the first female to arrive tended to be located near the bottom of a hanging substrate. Dissecting sleeping females showed that they contained mature oocytes, indicating that sexually mature individuals formed aggregations. In male aggregations, however, we could not find a clear relationship between the position on substrates and the arrival sequence. We suggest that the purpose for sleeping in aggregations might be a dilution effect for nocturnal predation and that the females that finished both nesting and foraging quickly could choose the optimal positions in the aggregation when they arrived on the sleeping substrates.     

Enzymatic treatment of estrogens and estrogen glucuronide

Natural and synthetic estrogens from sewage treatment systems are suspected to influence the reproductive health of the animals in the rivers.In this article we investigated the enzymatic treatment of three estrogens (estrone,17β-estradiol,and 17α-ethynyletstradiol) by a fungal laccase which oxidize phenolic compounds with dissolved oxygen.The elimination of the estrogenic activities by enzymatic oxidation was demonstrated by medaka vitellogenin assay.In addition,we developed an enzymatic treatment system comprised of β-D-glucuronidase and the laccase for 17β-estradiol 3-(β-D-glucuronide) degradation.The two enzymes eliminated 17β-estradiol 3-(β-D-glucuronide) and the intermediate,17β-estradiol,efficiently.     

The impact of institutional factors on the performance of genuine savings

This study investigates institutional factors affecting the performance of genuine savings (GS), which are often used in assessing sustainable development, and adopts a model of autoregressive conditional heteroscedasticity in mean. We pay particular attention to the contribution of institutions to decrease the volatility level of the GS path. The estimation results show that there are two ways in which institutions affect GS performance. First, high quality of institutions enhances the GS level directly. Second, high quality of institutions enhances the GS level via stabilizing the volatility of the GS path. Considering both effects in their totality, institutional improvement plays an important role in realizing a sustainable development path.