Recycling potential of urban solid waste destined for sanitary landfills: the case of Indaiatuba, SP, Brazil.

The urban solid waste of the city of Indaiatuba (pop. 175 000), located in the state of S?o Paulo, was characterized, focusing on the recycling potential. For this purpose, collected waste was subdivided into 27 items, classified by mass and volume. About 90% of this waste was found to be potentially recyclable and only 10% requiring landfilling. The compostable organic matter, in the form of food and garden waste, both with high moisture content (51 and 41%, respectively), represents 54% in mass and 21% in volume. The most common type of plastic in this waste is high density polyethylene, whose estimated disposal is about 5000kgday(-1). A socio-economic analysis of the waste generation indicates that low-income neighbourhoods discard relatively less packaging and more food waste, shoes and construction debris than middle and high income ones, which may be due to low purchasing power and schooling. Our findings indicate that more aluminium and uncoloured polyethylene terephthalate is discarded in the warmest months of the year, probably due to a greater consumption of canned and bottled drinks.     

Does trade openness improve environmental quality?

The literature on trade openness, economic development, and the environment is largely inconclusive about the environmental consequences of trade. This study treats trade and income as endogenous and estimates the overall impact of trade openness on environmental quality using the instrumental variables technique. We find that whether or not trade has a beneficial effect on the environment varies depending on the pollutant and the country. Trade is found to benefit the environment in OECD countries. It has detrimental effects, however, on sulfur dioxide (SO₂) and carbon dioxide (CO₂) emissions in non-OECD countries, although it does lower biochemical oxygen demand (BOD) emissions in these countries. We also find the impact is large in the long term, after the dynamic adjustment process, although it is small in the short term.     

Mechanism of Depolymerization Reaction of Polyethylene Terephthalate: Experimental and Theoretical Studies

The depolymerization reaction of polyethylene terephthalate (PET) was analyzed on the basis of both experimental data and numerical data obtained from quantum chemistry calculations. Various alcohols were used as solvents in the search for the reaction mechanism. The activation energy obtained from the optimized structures of the ground state and the transitional state was compared with our experimental data. Based on these comparisons, it was found that the formation of rings from alkoxyl groups and carbonyl carbon atoms at the transitional state is highly important when the ester bonds of PET are broken. Moreover, the most appropriate alcohol was suggested for the depolymerization reaction.     

Effect of 17beta-estradiol on the reproduction of Japanese medaka (Oryzias latipes)

Estrogenic compounds such as 17beta-estradiol (E2) and its analogs are present in the aquatic environment and can adversely affect the reproductive systems of aquatic organisms. Although E2 has been detected at a maximum concentration of 64 ng/l in effluents of sewage treatment works (STWs), few reports address the associated effects on reproduction in fish. Therefore, we exposed adult medaka (Oryzias latipes) to mean measured E2 concentrations of 29.3, 55.7, 116, 227, and 463 ng/l for 21 d and assessed the effects on the egg number and fertility of paired medaka during the exposure period. In addition, we determined the hepatic vitellogenin (Vtg) concentration and histologically assessed the gonads of these fish. The number of egg produced and fertility of the paired medaka exposed to 463 ng/l E2 were significantly less compared with those of the control fish. Males in all treatment groups had developed testis-ova. Males treated with E2 concentrations = 55.7 ng/l contained relating great concentrations of hepatic Vtg. Therefore, although only the greatest E2 concentration tested in our study affected fecundity and fertility, effects of E2 were observed on induction of Vtg and testis-ova in male medaka exposed to environmentally relevant concentrations of E2.     

Stabilities of 58 volatile organic compounds in fused-silica-lined and SUMMA polished canisters under various humidified conditions

Fused-silica-lined (FSL) canisters and SUMMA polished (SUMMA) canisters were compared for the recoveries and the stabilities of 58 volatile organic compounds (VOCs) at low ppbv (volume/volume) levels under various humidified conditions using a three-stage preconcentration method followed by GC-MS analysis. The target VOCs included non-polar VOCs (e.g. halogenated hydrocarbons and aromatic hydrocarbons) and polar VOCs (e.g. alcohols, ketones, esters, ethers, nitriles and thiols). The three-stage preconcentration method was initially optimized for simultaneous analysis of non-polar and polar VOCs because determination of canister stability is dependent on the accuracy of analytical measurements. The method showed good linearity over the concentration range from 1 to 25 ppbv for all target analytes, and the correlation coefficients were higher than 0.9974. The method detection limits ranged from 0.023 to 0.39 ppbv. The test mixtures loaded in both type of canisters (n = 3) had concentrations of 1.7-2.5 ppbv per compound at ambient pressure under various humidified conditions (%RH = 1.6, 8.0, 27, 39, 53 and >99% with excess water present). All canister samples were initially analyzed on day 0 (after 6-12 h). The effect of competitive adsorption of water vapor and polar VOCs on active sites of interior surface was remarkably observed for SUMMA canisters. Polar VOCs had a greater requirement for water vapor to be present. The RH percentages that ensured good recovery on day 0 were RH > 8% for non-polar VOCs and RH > 27% for polar VOCs (except alcohols under the condition of RH > 99%). All thiols were not recovered from SUMMA canisters under all conditions. FSL canisters showed good recoveries of more than 86% for all VOCs under all conditions on day 0 (except alcohols under the condition of RH > 99%). The recoveries of alcohols in both canisters under the condition of RH > 99% displayed relatively low recoveries in the range 25-76% because of the partitioning effect into condensed water. The canister samples under the conditions of RH 8.0, 27, 53 and > 99% were analyzed for the stability test on days 3, 7, 14 and 28 after loading. All non-polar VOCs were reasonably stable in the FSL canisters under all examined conditions over 28 days. However, several polar VOCs that have relatively lower vapor pressure, e.g. MIBK, butyl acetate and alcohols except ethanol, showed unstable characteristics under relatively dry conditions (RH 8 and 27%) during 28 days. RH > 53% was needed to ensure good stabilities of all analytes except thiols with the recoveries of > 80% over 28 days for both canisters. Although the FSL canister showed good recoveries of more than 86% for thiols on day 0, drastic degradations were observed after day 3 and they were not detected after day 14.     

Comparative study of the effects of infrasound and low-frequency sound with those of audible sound on sleep

In order to compare the effects of infrasound and low-frequency sound on sleep with those of audible sound, healthy students were exposed to two kinds of sound, (a) infrasound and low-frequency sound (10, 20, 40, and 60 Hz), and (b) synthesized traffic noise with peak sound pressure level in low-frequency range (sound composed of low and audible frequency), throughout their sleep with the recording of the students' EEG. The effects were evaluated by the “reaction rate”. Concerning sound (a), the sound pressure level which causes the reactions of over 50% for the first time was used as the threshold sound pressure level signifying the occurrence of sleep disturbance. The threshold sound pressure levels of 10 and 20 Hz could not be evaluated. The threshold sound pressure levels of 40 and 63 Hz were 95 and 90 dB, respectively. With both sounds, the reaction rate was the highest in sleep stage 1 and the lowest in sleep stage 3+4. The pattern of sleep was little affected by sound (a). On the other hand, it was considerably affected by sound (b). These results suggest that audible sound has more harmful effects on sleep, compared with infrasound and low-frequency sound.     

Uptake and distribution of 90Sr and stable Sr in rice plants

The stable Sr content in the aboveground parts of rice plants at various growth stages, and the distributions of 90Sr and stable Sr in rice plant components, such as polished rice, rice bran, hull, straw and root, at harvest time, were determined. The total Sr content in the aboveground rice plants was dependent on the growth stage and followed the sigmoidal shape of the growth curve. The concentration of 90Sr among the different components of rice plants varied within two orders of magnitude, whereas the 90Sr/Sr concentration ratio had a constant value. Therefore, the translocation rate of 90Sr in rice plants had similar values to that of stable Sr. However, the 90Sr/Sr concentration ratio for the rice plants was different for each study site. Only 0.6% of the total Sr was found in polished rice, while more than 99% was found in the non-edible components, of which 87% was present in the straw. These findings suggest that 90Sr in the non-edible parts could have been transferred to humans through the soil-plant system and/or feed-livestock pathway. The soil-to-plant transfer factor of 90Sr in polished rice was 0.0021 +/- 0.00007, which was two orders of magnitude lower than that in the straw. The percentage of 90Sr removed from the upper soil layer to the aboveground biomass of rice plants at harvest time was calculated as 0.094%. It is possible that approximately 0.1% of the total 90Sr content in the surface soil layer is removed from the soil-plant system by human activities every year.     

Estimation on Biodegradability of Poly (3-hydroxybutyrate-<Emphasis Type="Italic">co</Emphasis>-3-hydroxyvalerate) (PHB/V) and Numbers of Aerobic PHB/V Degrading Microorganisms in Different Natural Environments

To assess the capacity of the natural environment for degrading PHB/V, the film-MPN method proposed previously was modified to estimate the numbers of PHB/V degrading microorganisms (degraders) in various environments. The First-Order Reaction (FOR) model was used to determine the appropriate incubation period for the method. Numbers of aerobic PHB/V degraders were estimated in garden soil, paddy field soil, farm soil, river bank soil, infertile garden soil, river water, activated sludge, and seawater by the film-MPN method. Results were compared with those estimated by the clear-zone technique and showed that the film-MPN method was suitable for estimating the numbers of PHB/V degraders in the environments tested. On the other hand, biodegradability of injection molded PHB/V samples was investigated in several kinds of environments. The changes of weight were studied and results showed that biodegradability of PHB/V related to the numbers of PHB/V degraders in similar ecosystem in different regions. In different environments the biodegradability of PHB/V not only related to the number of PHB/V degraders, but also depended on whether there were conditions for the PHB/V degraders to grow and proliferate easily in the environment.     

The outcome of pregnancy and prenatal chromosomal diagnosis of fetuses in couples including a translocation carrier

In order to evaluate the relation between chromosomal translocation and the outcome of pregnancy, 50 couples were examined. Subjects consisted of 35 couples that included a reciprocal translocation carrier; 13 included a Robertsonian translocation carrier and 2 included a carrier of a mosaic reciprocal translocation. The reasons for performing chromosomal examinations were mainly infertility and abnormality of neonates. The rates of miscarriages and neonatal abnormalities in prior pregnancies were significantly higher than the birth rate of morphologically normal newborns. The presence of a translocation is closely related to reproductive failure because of the chromosomal imbalance. However, prenatal chromosomal examination after the 15th gestational week in subsequent pregnancies revealed that almost half of the fetuses showed normal karyotypes and only 12.8 per cent of the fetuses showed a chromosomal imbalance. Many chromosomally imbalanced fetuses are spontaneously aborted before amniocentesis. The risk of chromosomal imbalance is relatively low in prenatal diagnosis, but partial trisomies of small rearrangements tend to be preserved.     

Prenatal diagnosis of tyrosinase-negative oculocutaneous albinism by an electron microscopic dopa reaction test of fetal skin

An electron microscopic DOPA reaction test of fetal skin was used for the prenatal diagnosis of tyrosinase-negative oculocutaneous albinism (OCA). The subject was a 34-year-old Japanese woman in her second pregnancy. Her first child, born in 1982, had been previously examined and confirmed to have tyrosinase-negative OCA. The parents requested a prenatal diagnosis and we sampled skin from the upper trunk of the fetus. On conventional electron microscopy, the development of melanosomes in interfollicular melanocytes had progressed no further than stage II. Fetal skin samples incubated with L-DOPA solution indicated a lack of tyrosinase activity and showed that the melanosomes had not progressed beyond stage II. In skin samples from the trunks of three Japanese fetuses aborted for other reasons at 19–20 weeks of gestation, most premature melanosomes were further melanized to stage IV after incubation with L-DOPA solution. A prenatal diagnosis of tyrosinase-negative OCA was made. The parents requested a termination and skin biopsies of the abortus confirmed the diagnosis. This study shows that tyrosinase is normally present in melanocytes of the fetal epidermis at 20 weeks' gestation, and that the electron microscopic DOPA reaction test of a fetal skin biopsy specimen is safe and practical, and provides reliable information for making a prenatal diagnosis of tyrosinase-negative OCA in the second trimester.