Sources of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs), and their bioaccumulation through the marine food web in Sendai Bay,Japan

The concentrations of PCDD/F and Co-PCB congeners in seawater, sediment, Pacific oyster, Japanese anchovy, marbled sole, and Japanese flounder samples from Sendai Bay, Japan, were analyzed. The compositions of total PCDD/F and total Co-PCB concentrations in sediment and Pacific oyster reflected that in seawater--the compositions of total PCDD, PCDF, and Co-PCB concentrations were approximately 60, 10, and 30%, respectively. The compositions in Japanese anchovy, marbled sole, and Japanese flounder were different from those in seawater and sediment-the ratio of total Co-PCB concentration to total PCDD/F plus Co-PCB concentrations in Japanese anchovy, marbled sole, and Japanese flounder was above 90%. Tetrachlorinated PCDDs (T4CDDs), such as 1,3,6,8- and 1,3,7,9-T4CDD, were the predominant congeners in seawater and sediment; the total T4CDD concentrations in seawater and sediment were approximately 46 and 48% of the total PCDD concentration. Furthermore, shipments of the herbicide 1,3,5-trichloro-2-(4-nitrophenoxy)benzene to Miyagi Prefecture, the so-called granary of Japan, were the highest in Japan over the last 12 years. The major sources of PCDD/Fs and Co-PCBs in Sendai Bay, which is in Miyagi Prefecture, are impurities in chlorinated herbicides. The order of concentration of PCDD/Fs was Pacific oyster > Japanese anchovy = marbled sole > Japanese flounder; the concentration in Japanese flounder, which is a higher-trophic-level consumer in the marine food web, was lower than that in shellfish (Pacific oyster) and Japanese anchovy, which are lower-trophic-level consumers. The order of concentration of Co-PCBs was Pacific oyster < Japanese anchovy = marbled sole < Japanese flounder; the concentrations in the higher-trophic-level consumers were higher than the concentrations in the lower-trophic-level consumers. Different PCDD/F congeners tended to bioaccumulate in different organisms. On the other hand, all species of Co-PCB congener tended to bioaccumulate in all organisms.     

Long-Term Observation of Asian Dust in Changchun and Kagoshima

Monitoring of Asian dust at two stations in Changchun, Jilin Province in northeast China, and Kagoshima, southwest Japan, is discussed. In Changchun, interval records were made with digital and video cameras from 18 March 2003. In Kagoshima, a web camera system to monitor volcanic clouds has been working since December 2000, which also provides data for studies of dust. A heavy dust episode on 11 November 2002, affecting both stations, was detected using 11 and 12 μm channels of NOAA/AVHRR. We observed dust in Changchun on 26 March, 7, 14–16 April, 1–2, 8, 10, 19 May, 8, 23 June, and 12 July in 2003. The observed images corresponded well to NOAA/AVHRR imagery and with 8.6, 11 and 12 μm Terra/MODIS results, although conditions were too cloudy for satellite verification in some cases.     

Rapid response to changing light environments of the calanoid copepod<Emphasis Type="Italic"> Calanus sinicus</Emphasis>

Calanus sinicus is a large calanoid copepod and a dominant species in the coastal waters of Japan. During a research cruise in Sagami Bay on 18 June 1996, we found C. sinicus performing an unusual diel vertical migration (DVM), a behavior that has not been reported in previous studies on this species. This study examined the DVM of C. sinicus under different light environments and revealed the copepods characteristic response to light. Field and laboratory results show that the DVM of C. sinicus is flexible and also confirmed its sensitivity and its rapid response to changing light environments. It is suggested that C. sinicus reacts to changes in absolute light intensity. This feature may be common in oceanic copepod species. The copepods quick reaction to light variation provides decreased predation risks and increased feeding opportunities, which make them a dominant survivor in coastal water habitats.Communicated by T. Ikeda, Hakodate     

Identification of Sources Contributing to Mid-Atlantic Regional Aerosol

Abstract

Source types or source regions contributing to the concentration of atmospheric fine particles measured at Brigantine National Wildlife Refuge, NJ, were identified using a factor analysis model called Positive Matrix Factorization (PMF). Cluster analysis of backward air trajectories on days of high- and low-factor concentrations was used to link factors to potential source regions. Brigantine is a Class I visibility area with few local sources in the center of the eastern urban corridor and is therefore a good location to study Mid-Atlantic regional aerosol. Sulfate (expressed as ammonium sulfate) was the most abundant species, accounting for 49% of annual average fine mass. Organic compounds (22%; expressed as 1.4 × organic carbon) and ammonium nitrate (10%) were the next abundant species. Some evidence herein suggests that secondary organic aerosol formation is an important contributor to summertime regional aerosol.

Nine factors were identified that contributed to PM_2.5 mass concentrations: coal combustion factors (66%, summer and winter), sea salt factors (9%, fresh and aged), motor vehicle/mixed combustion (8%), diesel/Zn-Pb (6%), incinerator/industrial (5%), oil combustion (4%), and soil (2%). The aged sea salt concentrations were highest in springtime, when the land breeze-sea breeze cycle is strongest. Comparison of backward air trajectories of high- and low-concentration days suggests that Brigantine is surrounded by sources of oil combustion, motor vehicle/mixed combustion, and waste incinerator/industrial emissions that together account for 17% of PM_2.5 mass. The diesel/Zn-Pb factor was associated with sources north and west of Brigantine. Coal combustion factors were associated with coal-fired power plants west and southwest of the site. Particulate carbon was associated not only with oil combustion, motor vehicle/mixed combustion, waste incinerator/industrial, and diesel/Pb-Zn, but also with the coal combustion factors, perhaps through common transport.     

Factors affecting the interval between clutches in the hermit crab <Emphasis Type="Italic">Pagurus nigrivittatus</Emphasis>

Interval between reproductive events is an important factor for iteroparous animals because it determines the number of clutches throughout life. This study examined whether female size, clutch size, shell size and prenuptial molting affected the clutch interval in the hermit crab Pagurus nigrivittatus. Precopulatory guarding pairs of P. nigrivittatus were sampled in the field and kept in the laboratory until the female extruded eggs. The clutch interval of each female was assessed as one of two types of relatively “short” and “long” intervals by checking whether the guarded female had eggs and/or egg cases from the preceding brood or not when the guarding pair was collected. The clutch interval was longer in females with prenuptial molting than those without molting and these females usually grew larger at the prenuptial molt. This suggests that female P. nigrivittatus with a long interval might allocate energy into growth at the expense of the number of clutches during the current reproductive season. The allocation to growth is theoretically predicted to decrease with female size. Gastropod shell size is also known to affect the reproductive activity in hermit crabs. However, female size did not significantly affect the clutch interval in P. nigrivittatus, and the effect of gastropod shell size on clutch interval was not consistent with previous empirical studies. These results may be caused by differences in the gastropod species of shell occupied by the females of P. nigrivittatus.     

Species richness patterns along environmental gradients in island land molluscan fauna

The relationship between species richness and environmental variables may change depending on habitat structure, dispersal ability, species mixing, and community adaptation to the environment. It is crucial to know how these factors regulate the environment-diversity relationship. The land molluscan fauna of the Ogasawara Islands in the West Pacific is an excellent model system to address this question because of the high species endemicity (> 90%), small area, and simple habitat structure of the islands. I examined relationships among indigenous species composition, richness, and habitat condition, and especially productivity and forest moisture on the island of Anijima. Two major communities of snails could be distinguished by detrended correspondence analysis (DCA): one group dominated in a moist habitat with high productivity, and the other group dominated in a dry habitat with low productivity. However, species richness became highest at the intermediate condition between the habitats in which the two snail communities were dominant, so that species richness showed a hump-shaped relationship with moisture and productivity. In contrast, the species richness of the snail community in the moist habitat showed a monotonically positive correlation, and that in the dry habitat showed a monotonically negative correlation with moisture and productivity. Thus, the greater species richness in intermediate moisture and productivity resulted from the ecotone effect or community overlap at the transitional areas, where faunas with different ecologies can meet in a single site. These findings suggest that hump-shaped productivity-diversity relationships in land Mollusca would reflect the ecotone effect as a result of the mixing of species adapted to either fertile habitats or sterile habitats.     

A case study on identification of airborne organic compounds and time courses of their concentrations in the cabin of a new car for private use

The cabin of an automobile can be considered to be a part of the living environment because many people spend long periods of time during business, shopping, recreation or travel activities. However, little is known about the interior air contamination due to organic compounds diffusing from the interior materials used in the interior of automobiles. In the present study, the compounds in the interior air of a new car were identified, and the time courses of their concentrations were examined for over 3 years after the delivery (July, 1999). A total of 162 organic compounds, involving many aliphatic hydrocarbons and aromatic hydrocarbons, were identified. High concentrations of n-nonane (458 microg/m(3) on the day following delivery), n-decane (1301 microg/m(3)), n-undecane (1616 microg/m(3)), n-dodecane (716 microg/m(3)), n-tridecane (320 microg/m(3)), 1-hexadecene (768 microg/m(3)), ethylbenzene (361 microg/m(3)), xylene (4003 microg/m(3)) and 2,2'-azobis(isobutyronitrile) (429 microg/m(3)) were detected, and the sum of the concentrations determined for all compounds excluding formaldehyde (TVOC) was approximately 14 mg/m(3) on the day after the delivery. The concentrations of most compounds decreased with time, but increased with a rise of the interior temperature. The TVOC concentration in the next summer (July, 2000) was approximately one-tenth of the initial concentration. During the 3-year study period, the TVOC concentrations in summer exceeded the indoor guideline value (300 mug/m(3)) proposed by [Seifert B. Volatile organic compounds. In: Maroni M, Seifert B, Lindvall T, editors. Indoor air quality. A comprehensive reference book. Air quality monographs, vol. 3. Netherlands: Elsevier Science; 1995. p. 819-21]. The interior temperature and days lapsed after delivery were the main factors affecting the interior concentrations of most compounds according to multiple linear regression analysis. The results of this study offer useful fundamental data for investigations on air pollution in automotive cabins due to the organic compounds diffusing from the interior materials.     

Identification of urinary metabolites in rats administered the fluorine-containing pyrethroids metofluthrin,profluthrin, and transfluthrin

The major metabolites in urine of rats administered the fluorine-containing pyrethroids transfluthrin, profluthrin, and metofluthrin, which are used widely recently as mosquito repellents or mothproof repellents, were identified to establish biological indexes for evaluating the absorption amounts of these pyrethroids in the general population. A single dose of 300?mg?kg^?1 body weight of each pyrethroid was separately administered intraperitoneally to male Sprague-Dawley rats and urine samples were collected until 24 hours after the administration. The metabolites identified by gas chromatography-mass spectrometry were as follows: 2,3,5,6-tetrafluorobenzyl alcohol, 2,3,5,6-tetrafluorobenzoic acid, and 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (DCCA) for transfluthrin; 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol, 4-methyl-2,3,5,6-tetrafluorobenzoic acid, 4-hydroxymethyl-2,3,5,6-tetrafluorobenzyl alcohol (HOCH₂–FB–Al), and 2,2-dimethyl-3-(1-propenyl)-cyclopropanecarboxylic acid (MCA) for profluthrin; 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol, HOCH₂–FB–Al and MCA for metofluthrin. In addition, several compounds estimated to be metabolites were detected as follows: hydroxylated DCCA and its lactone for transfluthrin; 4-hydroxymethyl-2,3,5,6-tetrafluorobenzoic acid (HOCH₂–FB–Ac), hydroxylated MCA and its lactone for profluthrin; 4-methoxymethyl-2,3,5,6-tetrafluorobenzoic acid, HOCH₂–FB–Ac, hydroxylated MCA, and its lactone for metofluthrin. The pyrethroids administered underwent metabolic reactions such as ester hydrolysis and oxidation, and most of the metabolites were excreted as their conjugates into urine. These findings should be useful as basic data for evaluating the health effects of exposure to pyrethroids for the general population.