Manganese toxicity as indicated by visible foliar symptoms of Japanese white birch (Betula platyphylla var. japonica)

For the purpose of a field diagnosis of Mn toxicity, we showed the possibility of using visible foliar symptoms of Japanese white birch (Betula platyphylla var. japonica Hara) as indicator. To examine the relationship between the expression of visible symptoms and leaf Mn concentrations, white birch seedlings were grown under four different Mn levels: 1 mg Mn l-1 as control, 10, 50 and 100 mg Mn l-1. Foliar symptoms of Mn toxicity for white birch were: (1) chlorosis at entire young leaves in the 50 and 100 mg Mn l-1 treatments; and (2) brown speckles at the leaf marginal and interveinal area for old leaves in the treatments greater than 1 mg Mn l-1. Mn preferably accumulated into the leaf marginal and interveinal area, where the brown speckles were observed. The mechanism determining the expression of symptoms seems to be associated with the physiological state related to leaf age as well as Mn distribution and concentration within a leaf.     

Formation of PCDDs and PCDFs during the combustion of polyvinylidene chloride and other polymers in the presence of HCl

PVDC and three non-chlorinated polymers (PP, PET, and PA) were incinerated at 700-850 degrees C in a laboratory-scale quartz tubular furnace in the presence of HCl (ca. 500 ppm congruent with 0.8 mg/l), and the gas-phase formation of PCDD/Fs, their putative precursors and their homologue profiles were investigated. The addition of HCl had little or no apparent effect on the level of PCDD/Fs formation during PVDC combustion, and their homologue profiles were quite different from those of the three non-chlorinated polymers. With PVDC, O8CDD and particularly O8CDF were by far most prevalent, apparently as a result of the selective formation of the precursors. With each of the three non-chlorinated polymers, combustion at 800 degrees C or higher in the presence of HCl resulted in PCDD/Fs formation at levels equaling or exceeding those observed with PVDC. In trials made with one of them (PP) under the same conditions but using a large polymer sample (100 mg vs 20 mg in all other trials), the level of PCDD/Fs formation was far higher than with the smaller polymer samples, and thus demonstrated the importance of appropriate combustion conditions for polymer incineration.     

The role of metals in dioxin formation from combustion of newspapers and polyvinyl chloride in an incinerator

Newspapers impregnated with NaCl mixed with various chloride metals (CuCl2, MgCl2, MnCl2, FeCl3, NiCl2, and CoCl2) and electric wire coated with polyvinyl chloride (PVC) were combusted in a well-controlled incinerator. Exhaust gas samples collected at the outlet of the incinerator were analyzed for dioxins (PCDDs, PCDFs, and coplanar PCBs) by gas chromatography/mass spectrometry. The amount of total dioxins formed from newspaper samples ranged from 34.2 ng/g (with NaCl+CoCl2) to 67.0 ng/g (with NaCl+CuCl2). PCDFs composed 88-94% of the total dioxins formed in the exhaust gases. The highest levels of PCDF isomers obtained were Cl3-CDF from the sample with NaCl+CuCl2 (14.8 ng/g), Cl2-CDF from the sample with NaCl+MgCl2 (12.3 ng/g), and Cl(1)-CDF from samples with NaCl+MnCl2 (12.6 ng/g), with NaCl+FeCl3 (11.8 ng/g), and with NaCl+NiCl2 (13.3 ng/g), and with NaCl+CoCl2 (8.62 ng/g). The total of Cl4-8-CDDs comprised 76-88% of the total Cl1-8-CDDs. In particular, Cl7-CDDs had the highest levels except for the sample with NaCl+NiCl2. Total dioxins formed from samples of electric wire coated with PVC and PVC alone were 38.3 ng/g and 112 ng/g, respectively, suggesting that the presence of copper reduced dioxin formation.     

Source and behavior analyses of dioxins based on congener-specific information and their application to Tokyo Bay basin

Identification of pollution sources and estimation of their contribution to dioxin pollution are important for taking better countermeasures against such sources. The information based on seventeen 2,3,7,8-chlorine-substituted congeners and 10 homologues is usually not sufficient for source identification. The usefulness of detailed congener-specific information of tetra- to octachlorinated polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans was examined by principal component analysis and compared with conventional dioxin information. It was revealed that congener-specific information was far more effective for source identification than conventional information. For source apportioning, it was shown that multiple regression analysis with detailed source congener profiles could be carried out successfully when calculations were performed for individual homologues. This was because of the large variation in homologue composition in source dioxin profiles in addition to the difference in environmental behavior among the homologues.The newly proposed methods for statistical analysis were applied to the estimation of dioxin mass balance in Tokyo Bay basin. It was found that Tokyo Bay sediment core contained dioxins from three major sources: combustion, pentachlorophenol (PCP), and chloronitrophen (CNP). PCP and CNP contained large amounts of dioxin as impurity and were used extensively as paddy field herbicides in Japan in the past. The total dioxin load from the two herbicides to the basin during the past 45 years (1951-1995) was estimated to be five times larger than that from combustion source in terms of toxic equivalents (WHO-TEQ). However, in the surface sediment of the bay, the contribution from the herbicides was nearly equal to that from combustion. The herbicide contribution peaked during the 1960s and 1970s and gradually decreased thereafter.     

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.     

Experimental assessment of factors influencing microhabitat selection by the two tidepool fishes Oligocottus maculosus and O. snyderi

Oligocottus maculosus Girard and O. snyderi Greeley are two similar tidepool fishes with differing, but overlapping, intertidal distribution patterns. The factors influencing microhabitat selection and distribution patterns were experimentally assessed to elucidate the mechanisms by which the two species partition the resources of the intertidal environment. O. snyderi displays a much more rigid substrate-cover requirement. This, combined with its stenothermal nature serve to strongly restrict the intertidal distribution of this species. O. maculosus has a more generalized substrate-cover requirement and is also known to be eurythermal and euryhaline. Thus, O. maculosus is a ubiquitous intertidal species. Other behavioral attributes of O. maculosus, such as its tide-related locomotor activity and preference for shallow water, facilitate its particular intertidal distribution pattern. Similar depth preferences or tide-related activity were not observed in O. snyderi. Interspecific competition and related agonistic behavior were absent from both species and are probably not important to their microhabitat selection and intertidal distribution patterns.Based on a portion of a dissertation submitted in partial fulfillment of the requirements for the Ph.D. degree at the University of British Columbia, Vancouver, B.C., Canada     

Spatiotemporal variations in rocky intertidal malacofauna throughout Japan in the 1970s and 1980s

Spatial and temporal variations of benthic fauna over a wide region (>1,000 km) that includes complex ocean currents have seldom been quantitatively studied. The present study revealed malacofaunal variations on Japanese rocky shores affected by the Soya, Tsushima, Oyashio, and Kuroshio currents, and in the Inland Sea. On 29 shores in seven regions in these sea areas, previous researchers have recorded the number of molluscs in quadrats in spring and summer of 1978 and 1984–1986. Reanalyses of these records revealed the following patterns. (1) Shore-to-shore variation in malacofauna was correlated with shore-to-shore geographical distance less clearly for more southern regions. This might show that in southern regions many taxa with low relative abundance are haphazardly recorded on some shores and blur the effect of shore-to-shore distance on malacofaunal dissimilarity. (2) Region-to-region variation in malacofauna was significantly correlated with region-to-region geographical distance. This suggests the influences of environments and paleontological events specific to each current surrounding each region. (3) The pattern of dissimilarity between the Inland Sea and the other sea areas greatly changed from the 1970s to 1980s. This was due in part to the following density fluctuations on some shores in the Inland Sea: increases in the non-indigenous mussel Mytilus galloprovincialis, cultured oyster Crassostrea gigas, and littorinid Littorina brevicula reportedly abundant in sheltered areas; and decreases in the littorinid Nodilittorina radiata reportedly abundant in exposed areas and muricid gastropods Thais spp. showing imposex. This suggests an increase of anthropogenic perturbations during the study period in the Inland Sea which is surrounded by large cities and ports. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effect of ultraviolet-absorbing vinyl film on organophosphorus insecticides dichlorvos and fenitrothion residues in spinach

Dichlorvos and fenitrothion residues found in spinach grown in greenhouse covered either by regular vinyl film or UV-absorbing vinyl film (UV-A) were analyzed by gas chromatography. After one day, dichlorvos residues in spinach covered with regular vinyl film and UV-A degraded by 97% and 80%, respectively, and degraded 100% after three days covered with regular vinyl film and six days covered with UV-A. After three days, fenitrothion residue in spinach covered with regular vinyl film degraded by 72% and then by 97% after six days; residue in spinach covered with UV-A degraded by 50% after three days and by 95% after six days. These results indicate that UV-A used to prevent the occurrence of insects and fungi in greenhouses reduced the degradation rates of dichlorvos and fenitrothion.     

Emission of organic compounds by combustion of waste plastics involving vinyl chloride polymer

Organic compounds emitted from combustion of waste plastics involving vinyl chloride polymer were investigated in an actual waste incinerator. The amounts of volatile aliphatic hydrocarbons and volatile chlorinated organic compounds decreased when the secondary combustion temperature was controlled over 900°C. On the other hand, the amounts of some aromatic hydrocarbons increased with a rise of the secondary combustion temperature.