Toxicity of uranium mine receiving waters to early life stage fathead minnows (Pimephales promelas) in the laboratory.

Elevated concentrations of arsenic, nickel, and molybdenum in aquatic systems around northern Saskatchewan uranium mines are an environmental concern. Early life stage fathead minnows were used to assess toxicity from several aquatic systems near the Key Lake and Rabbit Lake uranium operations. Hatching success of fish embryos exposed to waters receiving contaminants associated with uranium ore milling was reduced by 32-61% relative to controls. Mortality differed in two lakes receiving mill effluents because of opposing factors influencing metal toxicity (i.e. low pH and high hardness). In one mill receiving water (Fox Lake), larval mortality was 0%, whereas mortality was 85% in water collected from a downstream location (Unknown Lake). Fish embryos exposed to open-pit dewatering effluent receiving waters, or water from a flooded open pit (i.e. pit waters), hatched 26-39% earlier than those exposed to reference or control water. The combination of low water hardness and elevated nickel concentrations in pit waters contributed to the early hatching. Egg hatchability and hatching time were more sensitive indicators of toxicity than 'standard' endpoints, like larval mortality and growth. Current regulatory emphasis on single contaminants and standard toxicological endpoints should be re-evaluated in light of the complex interaction among confounding variables such as pH, hardness. conductivity, and multi-metal mixtures.     

Genetic connectivity among color morphs and Pacific archipelagos for the flame angelfish, <Emphasis Type="Italic">Centropyge loriculus</Emphasis>

Color variation is used in taxonomic classification of reef fishes, but it may not reliably indicate evolutionary divergence. In the central Pacific, there are three color morphs of the flame angelfish, Centropyge loriculus: a red morph that occurs primarily in the Hawaiian archipelago, the endemic Marquesan color morph with reduced black markings, and an orange morph that occurs throughout the rest of Oceania. The red and orange morphs co-occur at Johnston Atoll (1,300 km south of Hawai’i), but intermediate forms have not been reported. To determine whether the three color morphs represent distinct evolutionary lineages, we compared 641 base pairs of mitochondrial cytochrome b. Forty-one closely related haplotypes were observed in 116 individuals. Analysis of molecular variance (AMOVA) indicated no significant genetic structure among color morphs (Φ_ST = 0.011, P = 0.147). Likewise, there was no significant pairwise structure between sampling locations, separated by up to 5,700 km, after a Bonferroni correction (Φ_ST = 0.000–0.080, P = 0.0130–0.999). Genetic studies in conjunction with larval distribution data indicate that Centropyge species are highly dispersive. While there is a strong geographic component to the distribution of color morphs in C. loriculus, we find no evidence for corresponding genetic partitioning. We do not rule out an adaptive role for color differentiation, but our data do not support emerging species.     

Metals in Feathers of Bonin Petrel, Christmas Shearwater, Wedge-Tailed Shearwater, and Red-Tailed Tropicbird in the Hawaian Islands, Northern Pacific

Levels of environmental pollutants are usually higher in mainland and coastal areas than in offshore or oceanic islands due to higher inputs from agricultural and industrial sources. Levels of heavy metals are usually higher in adult than in young birds, because they have had longer to accumulate metals in their tissues, and/or because they may eat larger, more contaminated, prey. We examined the levels of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in the adults and young of Bonin petrel (Pterodroma hypoleuca), Christmas shearwater (Puffinus nativitatis) and red-tailed tropicbird (Phaethon rubricauda) on Midway Atoll, and adult wedge-tailed shearwater (Puffinus pacificus) on Midway Atoll and on Manana Island (off Oahu) in the northern Pacific. All birds were analyzed individually except for Christmas Shearwater chicks where samples were pooled to obtain sufficient quantities for analysis. Significant (p<0.05) age-related differences were found for mercury, selenium, manganese and chromium in Bonin petrels, for selenium and mercury in Christmas shearwaters, and for chromium and mercury in Red-tailed Tropicbirds. Lead approached significance for all three species. Adults had higher levels than young except for chromium and manganese in the petrels and arsenic in all three species. There were significant interspecific differences in concentrations of all metals except arsenic for the adults nesting on Midway. Christmas shearwaters had the highest levels of all metals except mercury and chromium. Bonin petrels, the smallest species examined, had mercury levels that were over three times higher than any of the adults of the other three species. For wedge-tailed shearwaters, levels of chromium and lead were significantly higher, and manganese and selenium were lower on Midway than Manana. Knowledge of the foraging ranges and habits of these far-ranging seabirds is inadequately known, but does not currently explain the observed differences among species. We could not find a consistent pattern of differences between the burrow nesting species (Bonin petrel, Wedge-tailed shearwater) and the surface nesting tropicbirds. There was no consistent pairwise correlation between any metals across all species.     

浅析环境监测QC/QA过程的采样环节

对环境监测布点采样中的QC/QA以及由采样引起的误差来源做了简要分析,并对监测采样过程中QC/QA的操作提出了一些设想。     

False-negative prenatal exclusion of Wiskott-Aldrich syndrome by measurement of fetal platelet count and size

The study of the fetal platelet count and size can, according to the literature, be used for the prenatal diagnosis of the Wiskott-Aldrich syndrome (WAS). So far, no affected fetuses have been identified by this method. All pregnancies in which this method had been applied to resulted, as correctly predicted, in the birth of normal children. Here we report on a familial case of WAS where the haematological parameters failed to reveal the affected second child. Hence we assume that the platelet count and size of platelets remain normal in fetuses with WAS to the gestational age of 22 weeks and cannot be used for prenatal diagnosis.     

Aerosol trace metals,particle morphology and total gaseous mercury in the atmosphere of Oxford,UK

An investigation of atmospheric trace metals was conducted in Oxford, UK, a small city ～60 miles northwest of London, in 2007 and 2008. Concentrations of Sr, Mo, Cd, Pb, V, Cr, Mn, Fe, Co, Ni, Cu and Zn in aerosol were measured in bulk and size segregated samples. In addition, total gaseous mercury (TGM) concentrations were monitored semi-continuously by cold vapour-atomic fluorescence spectroscopy. Metal concentrations in Oxford were intermediate between previously reported levels of UK rural and urban areas for most metals studied and levels of Cd, Ni and Pb were within European guidelines. Metal concentrations appeared to be influenced by higher traffic volume on a timescale of hours. The influence of traffic on the aerosols was also suggested by the observation of carbonaceous particles via scanning electron microscopy (SEM). Air mass back trajectories suggest air masses arriving in Oxford from London and mainland Europe contained the highest metal concentrations. Aerosol samples collected over Bonfire Weekend, a period of intense firework use and lighting of bonfires in the UK, showed metal concentrations 6–46 times higher than at other times. Strontium, a tracer of firework release, was present at higher concentrations and showed a change in its size distribution from the coarse to fine mode over Bonfire Weekend. The presence of an abundance of spherical Sr particles was also confirmed in SEM images. The average TGM concentration in Oxford was 3.17 ng m^?3 (st. dev. 1.59) with values recorded between 1.32 and 23.2 ng m^?3. This is a higher average value than reported from nearby rural locations, although during periods when air was arriving from the west, similar concentrations to these rural areas were seen in Oxford. Comparison to meteorological data suggests that TGM in Oxford's air is highest when wind is arriving from the east/southeast. This may be due to emissions from London/mainland Europe with a possible contribution from emissions from a local crematorium situated 4 miles east of the sampling site. A diurnal pattern was also observed in the TGM data with a minimum concentration during the day when mercury may have been diluted by thermal mixing of the atmospheric boundary layer. Additionally, this diurnal pattern may reflect variations in a local source of TGM.     

Kin recognition and cannibalistic behaviours by adult male fathead minnows (<Emphasis Type="Italic">Pimephales promelas</Emphasis>)

Parental care is an energetically demanding activity that ensures genes are efficiently passed from one generation to the next. According to evolutionary theory, the greatest energetic investment should be directed towards offspring that are most closely related to the parent. Male fathead minnows, Pimephales promelas, provide this parental investment to developing embryos but not newly hatched larvae. Therefore, selection should favour recognition of embryonic kin to ensure energetic expenditure is optimally invested. In this study, adult male fathead minnows were tested using behavioural assays, with egg cannibalism as an endpoint, to determine whether adult males could discriminate between related and unrelated embryos. Egg cannibalism was highest when adult male fathead minnows were presented with unrelated eggs and lowest when presented with eggs fertilized by the test subject (related eggs). The degree of cannibalism was also a function of breeding status. Unrelated males in breeding condition showed an intermediate response between the low cannibalism demonstrated by related males and the high cannibalism demonstrated by unrelated males in a nonbreeding condition. These results suggest that although male fathead minnows can discriminate between unrelated and related embryos, at least some component of parental investment is a simple function of breeding status.     

Radium-226 equilibrium between water and lake herring, Coregonus artedii, tissues attained within fish lifetime: confirmation in this species of one assumption in the simple linear concentration factor model

Equilibrium conditions are assumed in the simple linear concentration factor model commonly used in simulations of contaminant flow through ecosystems and in dose and risk calculations. Predictions derived from a power function model have suggested that if the time scale of the food-chain transfer is less than six years in fish, radium-226 equilibrium will not be achieved in nature, thereby violating the equilibrium requirement in the concentration factor model. Our results indicate (226)Ra equilibrium is achieved in a natural population of lake herring (Coregonus artedii), contrary to predictions of the power function model.     

The resilience of households to famine in el fasher, Sudan, 1982-89

This paper examines issues related to famine resilience and describes the results of a survey of households who migrated from famine affected rural communities in Northern Darfur to the provincial capital, El Fasher, in western Sudan. It reveals that asset wealth did not enhance household resilience to famine; rather, the data indicate that households who reportedly practiced more numerous survival strategies before migrating to El Fasher were on the whole able to stay longer in their villages before migrating. The data also suggest that some households might have been better able to endure the deteriorating rural conditions by participating in intra-communal practices of sharing resources. An additional issue influencing the timing of migration to El Fasher is previous familiarity with the economic opportunities in the provincial capital.     

The use of tree-rings and foliage as an archive of volcanogenic cation deposition

Tree cores (Pinus nigra ssp. laricio) and leaves (Castanea sativa) from the flanks of Mount Etna, Sicily were analysed by ICP-MS to investigate whether volcanogenic cations within plant material provide an archive of a volcano's temporal and spatial depositional influence. There is significant compositional variability both within and between trees, but no systematic dendrochemical correlation with periods of effusive, explosive or increased degassing activity. Dendrochemistry does not provide a record of persistent but fluctuating volcanic activity. Foliar levels of bioaccumulated cations correspond to modelled plume transport patterns, and map short-term volcanic fumigation. Around the flanks of the volcano foliar variation is greater for volatile cations (Cs, Cd, Pb) than for lithophilic cations (Ba, Sr), consistent with trace-metal supply from volcanic aerosol during quiescent periods.