Ionic composition of TSP and PM2.5 during dust storms and air pollution episodes at Xi'an,China

TSP and PM_2.5 samples were collected at Xi'an, China during dust storms (DSs) and several types of pollution events, including haze, biomass burning, and firework displays. Aerosol mass concentrations were up to 2 times higher during the particulate matter (PM) events than on normal days (NDs), and all types of PM led to decreased visibility. Water-soluble ions (Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, F^?, Cl^?, NO₃^?, and SO₄^2?). were major aerosol components during the pollution episodes, but their concentrations were lower during DSs. NH₄⁺, K⁺, F^?, Cl^?, NO₃^?, and SO₄^2? were more abundant in PM_2.5 than TSP but the opposite was true for Mg²⁺ and Ca²⁺. PM collected on hazy days was enriched with secondary species (NH₄⁺, NO₃^?, and SO₄²) while PM from straw combustion showed high K⁺ and Cl^?. Firework displays caused increases in K⁺ and also enrichments of NO₃^? relative to SO₄^2?. During DSs, the concentrations of secondary aerosol components were low, but Ca²⁺ was abundant. Ion balance calculations indicate that PM from haze and straw combustion was acidic while the DSs samples were alkaline and the fireworks' PM was close to neutral. Ion ratios (SO₄^2?/K⁺, NO₃^?/SO₄^2?, and Cl^?/K⁺) proved effective as indicators for different pollution episodes.     

PBDEs in leachates from municipal solid waste dumping sites in tropical Asian countries: phase distribution and debromination

Polybrominated diphenyl ethers (PBDEs) are extensively used as flame retardants in many consumer products, and leachates from landfills have been identified as one of the possible sources of PBDEs in the environment. Meanwhile, the unprecedented economic and population growths of some Asian countries over the last decade have led to significant increases in the amount of waste containing PBDEs in that region. This study investigates the status of PBDEs in leachates from municipal solid waste dumping sites (MSWDS) in tropical Asian countries. A total of 46 PBDE congeners were measured, both in the adsorbed (n?=?24) and dissolved (n?=?16) phases, in leachate samples collected, from 2002 to 2010, from ten MSWDS distributed among the eight countries of Lao PDR, Cambodia, Vietnam, India, Indonesia, Thailand, the Philippines, and Malaysia. PBDEs were predominantly found in the adsorbed phase. Partitioning of PBDEs in the dissolved phase was associated with the presence of dissolved organic matter; the apparent organic carbon-normalized partition coefficients (K′_oc) of the BDE congeners were lower by two to four orders of magnitude than the K _oc predicted from the octanol–water partition coefficients (K _ow). The total PBDE concentrations from mono- to deca-BDEs ranged from 3.7 to 133,000 ng/L, and showed a trend toward higher concentrations in the more populous and industrialized Asian countries. The congener profiles in the leachates basically reflected the composition of PBDE technical mixtures. The occurrence of congeners not contained, or in trace concentrations, in technical products (e.g., BDEs 208, 207, 206, 202, 188, 179, 49, 17/25, 8, 1) was observed in most of the leachate samples, suggesting the debromination of technical mixtures, including BDE-209, in the MSWDS of tropical Asian countries. Moreover, the temporal trend indicated the reduction of BDE-209 over time, with a corresponding increase in and/or emergence of lower brominated PBDE congeners. The results indicated that MSWDS of tropical Asian countries are potential sources of environmental PBDEs, which may be transported to the aquatic environment via dissolution with dissolved organic matter. MSWDS could be amplifiers of PBDE toxicity in the environment, possibly through debromination.     

Source discrimination of heavy metals in sediment and water of To Lich River in Hanoi City using multivariate statistical approaches

The concentrations of Mn, Fe, Ni, Cr, Cu, Pb, Zn, As, and Cd were determined to evaluate the level of contamination of To Lich River in Hanoi City. All metal concentrations in 0–10-cm water samples, except Mn, were lower than the maximum permitted concentration for irrigation water standard. Meanwhile, concentrations of As, Cd, and Zn in 0–30-cm sediments were likely to have adverse effects on agriculture and aquatic life. Sediment pollution assessment was undertaken using enrichment factor and geoaccumulation index (I _geo). The I _geo results indicated that the sediment was not polluted with Cr, Mn, Fe, and Ni, and the pollution level increased in the order of Cu < Pb < Zn < As < Cd. Meanwhile, significant enrichment was shown for Cd, As, Zn, and Pb. Cluster and principal component analyses suggest that As and Mn in sediment were derived from both lithogenic and anthropogenic sources, while Cu, Pb, Zn, Cr, Cd, and Ni originated from anthropogenic sources such as vehicular fumes for Pb and metallic discharge from industrial sources and fertilizer application for other metals.     

Life history of the temperate subtidal gastropod Umbonium costatum

The life history and reproductive biology of the trochid sand snail Umbonium costatum (Kiener) were investigated on a subtidal sandy shore in Hakodate Bay, Japan between 1988 and 1991. Female U. costatum mature at 1 yr of age (shell diameter-11 mm), reproduce twice (in June-July and September-October) in successive years, grow to a maximum size (shell diameter=22 mm) at age 8 yr, increase annual fecundity with age from 2000 (age 1 yr) to 37000 (age 8 yr), and show a maximum monthly gonad somatic index of 8% which is constant among ages. In comparison to a previously studied life history of a tropical Umbonium vestiatium, temperate U. costatum shows more sustained growth and a longer life span after maturation. This could be explained by: (1) the optimal size model concerned with resource investment, in gametes (Sebens 1987); and by (2) bet hedging to compensate large variability in larval success at high latitudes. These two hypotheses are not mutually exclusive, but both are based on season-related extremes of environment at high latitudes where the period suitable for reproduction is short.     

A possible hybrid zone in the Mytilus edulis complex in Japan revealed by PCR markers

The adhesive protein allele of mussels collected at 13 points in Japan from Hokkaido to Kyushu was analyzed by the polymerase chain reaction using a set of primers which amplifies a part of the nonrepetitive region of the adhesive protein gene. While most mussels exhibited a 126 bp fragment, characteristic of the pure Mytilus galloprovincialis, 55 of 64 mussels sampled at Hiura and 1 of 14 mussels at Hakodate Port exhibited 168 and 126 bp fragments. Sequence analysis of the two fragments indicated that the 168 and 126 bp fragments are almost identical to previously reported sequences in M. trossulus and M. galloprovincialis, respectively. Since the frequency of heterozygous individuals in Hiura is very high, it is unlikely that they are simple hybrids. However, it is evident that mixing of genes occurred between the two species off Hokkaido. Received: 6 September 1996 / Accepted: 9 October 1996     

Comparison of polybrominated diphenyl ethers in fish, vegetables, and meats and levels in human milk of nursing women in Japan

At present, little is known about the occurrence of polybrominated diphenyl ethers (PBDEs) in fish and food products sold in Japan. To investigate whether human exposure to PBDEs through the diet is significant, the concentrations of PBDEs were determined in fish and in meat and vegetables sold in two food markets in the city of Hirakata, Osaka prefecture. The concentrations of PBDEs in the breast milk of 12 primiparae nursing women at one month after delivery also were determined to ascertain the relationship between the levels found in the diet and levels in humans. sigma PBDE concentrations ranged between 21 and 1650 pg/g fresh weight in the edible tissues of five species of fish and one shellfish species. The highest concentrations were measured in yellow-fin tuna, followed by short-necked clam, salmon, yellowtail, mackerel and young yellowtail. Interestingly, sigma PBDE concentrations were not statistically significantly different in two cultured mackerel samples from Japan and mackerel collected from northern European waters. sigma PBDE concentrations in beef, pork and chicken meat (ranging between 6.25 and 63.6 pg/g fresh weight) and in three different vegetables (ranging between 38.4 and 134 pg/g fresh weight) were significantly lower than the concentrations in fish. In human milk, sigma PBDE concentrations ranged between 668 and 2840 pg/g lipid basis, which is comparable to the levels in populations of nursing women reported in Sweden and elsewhere. There was a strong positive relationship between PBDE concentrations in human milk and dietary intake of fish and shellfish, which was established in the women from responses to a questionaire on food consumption habits. The results of this study of food products commonly consumed in Japan and the levels found in nursing women raise a concern about low level PBDE contamination of fish and other foods intended for human consumption.     

Formation of toxic chemicals including dioxin-related compounds by combustion from a small home waste incinerator

We investigated combustion in a small home waste incinerator and analyzed both flue gas and residual ash for formation of the dioxin-related compounds polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls and their precursors polychlorinated benzenes, polychlorinated phenols, polychlorinated diphenyl ethers, and polychlorinated biphenyls. Particularly, we investigated the effect of the incinerated material's composition on both the congener ratios of released compounds and the total concentration of all congeners of each compound. Eight different samples were prepared for incineration with four samples consist entirely paper, dead leaves, natural wood, or building materials. The remaining four samples contained mostly paper, but also other components such as fiber, non-chlorine-containing plastics, chlorine-containing plastics, and copper electric wire. The presence of non-chlorine-containing plastic in combustion samples did not increase overall dioxin or dioxin-precursor emissions. In contrast, chlorine-containing plastic resulted in a several-fold increase in total polychlorinated dioxins released, in both flue gas and residual ash. Copper wire resulted in a further several-fold increase in total polychlorinated dioxins and dioxin precursors released, with one exception: the addition of chlorine-containing plastic resulted in a many-fold increase in polychlorinated biphenyls, but only a modest further increase ( approximately 52%) with the further addition of copper. Homologue ratios tended toward higher-chlorine compounds as chlorine-containing plastic and Cu were added, but the results were far from uniform. Our results show that toxic dioxin release from small home waste incinerators must be considered significant, especially if even small amounts of chlorine-containing plastics or copper are burned.     

Non-indigenous macroalga hosts different epiphytic assemblages to conspecific natives in southeast Australia

Codium fragile ssp. tomentosoides is one of the five most invasive macroalgae worldwide. We compared epiphytic assemblages between native (ssp. tasmanicum and ssp. novae-zelandiae combined) and non-indigenous (ssp. tomentosoides) subspecies of Codium fragile on three rocky intertidal shores in southeast Australia. Twelve species of epiphytes covered up to 20% of the surface of both native and non-indigenous Codium subspecies, but none were unique to either subspecies. For C. fragile subspecies, epiphytic cover declined from the lower (older) parts of the thallus to the branch tips. The abundance and species composition of epiphytes differed significantly between native and non-indigenous C. fragile, but differences varied among rocky shores. Results demonstrate that non-indigenous C. fragile does not play a functionally similar role to closely related native Codium subspecies. Spatial differences in epiphytic assemblages between Codium subspecies among rocky shores demonstrate that effects of non-indigenous species may be strongly location specific. Thus, our study emphasises the need to investigate variation in the effects of invaders across the regional landscape.     

Optimization of the purification method for dioxin analysis in human serum and temporal changes in background dioxin levels in the general population

To perform high quality and high throughput measurements, complicated purification procedure by two rounds of open column chromatography was simplified by appraising the components and adding a sufficient amount of adsorbents to the column. The procedure consists of two open column techniques using a multi-layer silica gel column and an active carbon dispersed silica gel column. This purification procedure is used in "Standard manual for dioxin analysis in human blood" published in 2000 (Ministry of Health and Welfare, Japan, 2000). Consequently, a purification procedure using only 1 g of 10% AgNO(3)/silica gel can remove the matrix of blood serum as effectively as a multi-layer silica gel column. In addition, 0.1 g of carbon silica gel, equivalent to 1/10 the weight used currently in analyses, separates and recovers the dioxins in purified extract of blood serum. Furthermore, changes in the background level in the general population were clarified by monitoring the dioxin concentrations in human blood. The dioxin concentrations and ratios in blood in the general population remained at a tolerable level for three months. Therefore, the blood serum was available for the detection of a remarkable elevation in dioxins level considered to be indicative of contamination due to high-density exposure.