Speciation and preservation of inorganic arsenic in drinking water sources using EDTA with IC separation and ICP-MS detection

The native distribution of As(III) and As(v) in drinking water supplies can influence the treatment removal strategy. The stability of As(III) and As(v) in iron-rich drinking waters can be affected by the formation of Fe precipitates (Fe oxides and/or hydroxides designated by "FeOOH"). These precipitates (ppts) can form during the transport of the sample to the laboratory for arsenic speciation analysis. The analysis of the ppt indicates considerable loss of the aqueous arsenic species (As(aq)) to the solid phase "FeOOH" ppt. Studies of laboratory reagent water containing both As(III) and Fe(III) indicate that the resulting "FeOOH" ppt contained a mixture of As(III) and As(v) with near quantitative removal of the As(aq) in 18 hr. The corresponding aqueous fraction after filtration through a 0.45 microm filter was composed primarily of As(v). The formation of "FeOOH" ppt and the loss of As(aq) to the ppt can be virtually eliminated by the use of EDTA, which sequesters the FeIII). Reagent water fortified with Fe(III), As(III) and EDTA produced less than a 1 ppb change in the As(III)aq concentration over 16 d. The EDTA treatment was also tested on three well waters with different native As(III )/As(v) ratios. The native distribution of As(III)/As(v) was stabilized over a period of 10 d with a worst case conversion of As(III) to As(v) of 2 ppb over a 30 d period. All well waters not treated with EDTA had dramatic losses (a factor of 2-5) of As(aq) in less than 1 d. These results indicated that EDTA preservation treatment can be used to preserve As(aq) in waters where the predominant species is the reduced form [As(III)] or in waters which the predominant species is the oxidized form [As(v)]. This preliminary investigation of EDTA to preserve As species in Fe-rich waters indicates stability can be achieved for greater than 14 d.     

The condition of coral reefs in South Florida (2000) using coral disease and bleaching as indicators

The destruction of coral reef habitats has occurred at unprecedented levels during the last three decades. Coral disease and bleaching in the Caribbean and South Florida have caused extensive coral mortality with limited recovery, often coral reefs are being replaced with turf algae. Acroporids were once dominant corals and have diminished to the state where they are being considered as endangered species. Our survey assessed the condition of reef corals throughout South Florida. A probability-based design produced unbiased estimates of the spatial extent of ecological condition, measured as the absence or presence and frequency or prevalence of coral diseases and bleaching intensity over large geographic regions. This approach allowed us to calculate a quantifiable level of uncertainty. Coral condition was estimated for 4100 hectares (ha) (or 41.0 km²) of coral reefs in South Florida, including reefs in the Florida Keys National Marine Sanctuary (FKNMS), New Grounds, Dry Tortugas National Park (DTNP), and Biscayne National Park (BNP). The absence or presence of coral disease, causal coral bleaching, partial bleaching and coral paling were not good indicators of overall coral condition. It was more useful to report the prevalence of anomalies that indicated a compromised condition at both the population and community levels. For example, 79% of the area in South Florida had less than 6% of the coral colonies diseased, whereas only 2.2% (97.15 ha) of the sampled area had a maximum prevalence of 13% diseased coral colonies at any single location. The usefulness of causal bleaching might be more important when considering the prevalence of each of the three different states at a single location. For example, paling was observed over the entire area, whereas bleaching and partial bleaching occurred at 19 and 41% of the area, respectively. An index for coral reef condition might integrate the prevalence and species affected by each bleaching state at individual locations. By establishing these baselines, future surveys can examine changes and trends in the spatial distribution of coral conditions in South Florida and able to score the reefs as to their health status.     

A field study of the generation of nitrate in a hill cap cloud

A field experiment to investigate the formation of nitrate as an airstream passes through a hill cap cloud has been performed at the UMIST field station on Great Dun Fell. It has been shown that the aerosol nitrate concentration increased by about 0.5 microg m(-3) as the airstream passed through the cloud during the night. At sunrise the nitrate production disappeared. It is suggested that the most likely mechanism for this nitrate production was due to the solution of N2O5 and NO3 formed from the reaction of NO2 with O3. These higher oxides build up overnight in the absence of short wave radiation to photolyse them. Other possible mechanisms of nitrate production are also discussed.     

Using wind to power a groundwater circulation well—preliminary results

In areas of the country where the U.S. Department of Energy has classified the available wind resources as Class 3 or greater, the use of wind turbines to provide power to relatively small remediation systems such as groundwater circulation wells may be technically and economically feasible. Groundwater circulation wells are a good candidate technology to couple with renewable energy, because the remediation system removes contamination from the subject aquifer with no net loss of the groundwater resource, while the wind turbine does not create potentially harmful air emissions. Wind data collected in the vicinity of the former Nebraska Ordnance Plant Superfund site were used to select a wind turbine system to provide a portion of the energy necessary to power a groundwater circulation well located in an area of high trichloroethylene groundwater contamination. Because utility power was already installed at the remediation system, a 10 kW grid inter‐tie wind turbine system supplements the utility system without requiring batteries for energy storage. The historical data from the site indicate that the quantity of energy purchased correlates poorly with the quantity of groundwater treated. Preliminary data from the wind turbine system indicate that the wind turbine provides more energy than the remediation system treatment components and the well submersible pump require on a monthly average. The preliminary results indicate that the coupling of wind turbines and groundwater circulation wells may be an attractive alternative in terms of the system operation time, cost savings, and contaminant mass removal. © 2004 Wiley Periodicals, Inc.     

受西班牙阿斯纳科利亚尔黄铁矿有毒污染液影响的土壤和植物中镉和锌浓度

引言 阿斯纳科利亚尔矿处于自西班牙中南部延伸至葡萄牙的黄铜矿丰富地带,劳斯福若斯是该矿的一个新开采地点,位于西班牙南部塞维尔以西45km,于1996年开工.提炼具有极高商业价值的锌(Zn)、铅(Pb)和汞(Hg)等高等级矿石产生了大量的重金属矿泥污水和高酸度废水(pH 2),而这些废水贮存在残渣围坝内,1998年4月25日,一处50m宽的决口使600万m3富含重金属的酸性废水和有毒矿渣泥浆(2:1的比例)泄漏到流经唐娜纳的高迪亚玛河(Gaudiamar).     

The value of early third-trimester maternal serum alpha-fetoprotein determination

The value of determination of maternal serum of alpha-fetoprotein (MSAFP) concentration in i he second trimester is well established. In addition to open neural tube defects, pregnancies associated with elevated second-trimester MSAFP have been shown to be at increased risk for a variety of problems, including low birth weight, preterm delivery, and pregnancy-induced hypertension (PIH). We evaluated the potential usefulness of MSAFP in the early third trimester. MSAFP concentration was determined in over 200 women at the time of glucose screening. Results were analysed with regard to gestational age at sampling, maternal weight, race, diabetes, and presence of twins. MSAFP was twice as high in twin gestation, but not affected by race or the presence of diabetes. In contrast to levels in early gestation, third-trimester MSAFP does not appear to be predictive of preterm delivery, low birth weight, or PIH.     

The good soldier: who is s(he)?

This paper examines how perceptions of Organizational Citizenship Behaviors (OCBs) are affected by socially constructed gender roles. We argue that gender roles are important for the perception, categorization, and consequences of OCBs. We suggest that the dimensions of OCBs (altruism, courtesy, sportsmanship, and civic virtue) are related to gender stereotypes. Combining social identity theory with gender role theory suggests that the ‘gender’ of these behaviors, the job, the job incumbent, and the gender identity of the observer interact, potentially broaden the breadth of requisite job behaviors defined as either in‐ or extra‐role. Implications are discussed. Copyright © 2001 John Wiley & Sons, Ltd.     

Effects of vegetation cover, presence of a native ant species, and human disturbance on colonization by Argentine ants

The spread of non-native invasive species is affected by human activity, vegetation cover, weather, and interaction with native species. We analyzed data from a 17-year study of the distribution of the non-native Argentine ant (Linepithema humile) and the native winter ant (Prenolepis imparis) in a preserve in northern California (U.S.A.). We conducted logistic regressions and used model selection to determine whether the following variables were associated with changes in the distribution of each species: presence of conspecifics at neighboring sites, distance to development (e.g., roads, buildings, and landscaped areas), proportion of vegetation cover taller than 0.75 m, elevation, distance to water, presence of both species at a site, temperature, and rainfall. Argentine ants colonized unoccupied sites from neighboring sites, but the probability of appearance and persistence decreased as distance to development, vegetation cover, and elevation increased. Winter ants appeared and persisted in sites with relatively high vegetation cover (i.e., highly shaded sites). Presence of the 2 species was negatively associated in sites with high vegetation cover (more winter ants) and sites near development (more Argentine ants). Probability of colonization of Argentine ants decreased where winter ants were most persistent. At sites near development within the preserve, abundant Argentine ant populations may be excluding winter ants. The high abundance of Argentine ants at these sites may be due to immigration from suburban areas outside the preserve, which are high-quality habitat for Argentine ants. In the interior of the preserve, distance from development, low-quality habitat, and interaction with winter ants may in combination exclude Argentine ants. Interactions among the variables we examined were associated with low probabilities of Argentine ant colonization in the preserve.     

Evaluation of the water genotoxicity from Santos Estuary (Brazil) in relation to the sediment contamination and effluent discharges

The genotoxic activity of water samples collected in 9 different sites within the area of the Santos estuary was preliminary evaluated, and related to previous data on the genotoxicity of sediments and the contents of PAHs in both water and sediment samples. The liquid discharge of a steel mill (coke plant), known to be mutagenic, was chemically analyzed to determine its PAH content. For the water evaluation we employed the Salmonella/microsome assay with the strains TA98 and TA100 with and without S9 mix in the plate incorporation method. The water was filtered with an AP20 membrane before being extracted with XAD4 at natural and acidic pH. The industrial effluent was filtered in 0.45 microm membranes before being extracted with the liquid/liquid method. Both membranes containing the particulate material were extracted using ultrasonication. PAHs were found associated with the suspended particles present in the industrial effluent in accordance with mutagenicity data previously reported. In relation to the estuarine waters, sites 1 and 5 presented low levels of mutagenic activity only in the filtered water (liquid fraction) extracts. At site 3, both the filtered water and particulate solids presented also low mutagenicity. Results show that the mutagenic activity observed in water could not be directly related to the genotoxic activity and PAHs contents of the bottom sediments.