The internal microstructure and fibrous mineralogy of fly ash from coal-burning power stations

Coal fly ash (CFA) is a significant environmental pollutant that presents a respiratory hazard when airborne. Although previous studies have identified the mineral components of CFA, there is a paucity of information on the structural habits of these minerals. Samples from UK, Polish and Chinese power stations were studied to further our understanding of the factors that affect CFA geochemistry and mineralogy. ICP-MS, FE-SEM/EDX, XRD, and laser diffraction were used to study physicochemical characteristics. Analysis revealed important differences in the elemental compositions and particle size distributions of samples between sites. Microscopy of HF acid-etched CFA revealed the mullite present possesses a fibrous habit; fibres ranged in length between 1 and 10 μm. Respirable particles (<10 μm) were frequently observed to contain fibrous mullite. We propose that the biopersistence of these refractory fibres in the lung environment could be contributing towards chronic lung diseases seen in communities and individuals continually exposed to high levels of CFA.     

Open Air Laboratories (OPAL): a community-driven research programme

OPAL is an English national programme that takes scientists into the community to investigate environmental issues. Biological monitoring plays a pivotal role covering topics of: i) soil and earthworms; ii) air, lichens and tar spot on sycamore; iii) water and aquatic invertebrates; iv) biodiversity and hedgerows; v) climate, clouds and thermal comfort. Each survey has been developed by an inter-disciplinary team and tested by voluntary, statutory and community sectors. Data are submitted via the web and instantly mapped. Preliminary results are presented, together with a discussion on data quality and uncertainty. Communities also investigate local pollution issues, ranging from nitrogen deposition on heathlands to traffic emissions on roadside vegetation. Over 200,000 people have participated so far, including over 1000 schools and 1000 voluntary groups. Benefits include a substantial, growing database on biodiversity and habitat condition, much from previously unsampled sites particularly in urban areas, and a more engaged public.     

Validation of a passive atmospheric deposition sampler for polybrominated diphenyl ethers

An atmospheric deposition sampler was validated with respect to polybrominated diphenyl ethers (PBDEs), a compound group that is widely used as flame retardants in many types of consumer products. The deposition sampler consists of an adsorption cartridge that is connected to a glass funnel. Extraction tests with spiked cartridges using soxhlet extraction with acetone revealed recoveries of >80% for all of the investigated PBDEs. Once adsorbed, PBDEs are stable, as proven by extractions of spiked cartridges that were stored outdoors and collected after different periods of time, up to 84 days. High recoveries indicate that degradation of adsorbed PBDEs does not play a role under realistic field conditions. Bulk deposition rates of PBDEs were determined in a field test with 3 replicates, and a possible breakthrough of target compounds was assessed in the field using a second adsorption cartridge in series. No breakthrough of target compounds could be observed within a sampling period of 61 days, and a bulk deposition rate of approximately 1 ng m(-2) day(-1) for the sum of all analysed PBDEs was measured. The highest deposition rates were measured for octa-brominated congeners, followed by BDEs 99, 183, 153, and 47. Overall, the sampler was successfully validated regarding the atmospheric deposition of PBDEs.     

Perfluorooctane Sulfonate Increases the Genotoxicity of Cyclophosphamide in the Micronucleus Assay with V79 Cells: Further Proof of Alterations in Cell Membrane Properties Caused by PFOS (3 pp)

Background, Aim and Scope Perfluorooctane sulfonate (PFOS; C8F17SO3-) is a fully fluorinated organic compound which has been manufactured for decades and was used widely in industrial and commercial products. The recent toxicological knowledge of PFOS mainly concerns mono-substance exposures of PFOS to biological systems, leaving the potential interactive effects of PFOS with other compounds as an area where understanding is significantly lacking. However, a recent study, reported the potential of PFOS to enhance the toxicity of two compounds by increasing cell membrane permeability. This is of particular concern since PFOS has been reported to be widely distributed in the environment where contaminants are known to occur in complex mixtures. In this study, PFOS was evaluated alone and in combination with cyclophosphamide (CPP) to investigate whether a presence of PFOS leads to an increased genotoxic potential of CPP towards hamster lung V79 cells. Genotoxicity was investigated using the micronucleus (MN) assay according to the recent draft ISO/DIS 21427-2 method. PFOS alone demonstrated no genotoxicity up to a concentration of 12.5 mg/L. However, PFOS combined with two different concentrations of CPP, with metabolic activation, caused a significant increase in the number of micronucleated cells compared to treatments with CPP only. These results provide a first indication that PFOS has the potential to enhance the genotoxic action of CPP towards V79 cells, suggesting that together with the alterations in cell membrane properties shown previously, that genotoxicity of complex mixtures may be increased significantly by changes in chemical uptake. Together with an earlier study performed by the own working group it can be concluded that PFOS alone is not genotoxic in this bioassay using V79 cells up to 12.5 mg/L, but that further investigations are needed to assess the potential interaction between PFOS and other substances, in particular regarding the impact of membrane alterations on the uptake of toxic substances. Materials and Methods: - Results: - Discussion: - Conclusions: - Recommendations and Perspectives: -     

Identifying ozone-sensitive communities of (semi-)natural vegetation suitable for mapping exceedance of critical levels

Using published data on the responses of individual species to ozone, 54 EUNIS (European Nature Information System) level 4 communities with six or more ozone-sensitive species (%OS) and c. 20% or more species tested for ozone sensitivity, were identified as potentially ozone-sensitive. The largest number of these communities (23) was associated with Grasslands, with Heathland, scrub and tundra, and Mires, bogs and fens having the next highest representation at 11 and 8 level 4 communities each respectively. Within the grasslands classification, E4 (Alpine and sub-alpine grasslands), E5 (Woodland fringes and clearings) and E1 (Dry grasslands) were the most sensitive with 68.1, 51.6 and 48.6%OS respectively. It is feasible to map the land-cover for these and other communities at level 2, but it may not be currently possible to map the land-cover for all communities identified to be ozone-sensitive at levels 3 and 4.     

Restoration of the Kissimmee River, Florida: Water Quality Impacts from Canal Backfilling

The planned restoration of the Kissimmee River ecocystem will backfill approximately 35 km of flood control canal (C-38) that cuts through the meandering river channel, re-establish natural flow patterns, and restore the river/floodplain ecosystem. Water quality monitoring, including nutrients, total suspended solids (TSS), turbidity, dissolved oxygen (DO), and mercury, was conducted during a pilot `test fill' project to determine if soil disturbance during canal backfilling would negatively impact these water quality constituents. Surface water nutrient concentrations varied little between sites. Generally, highest concentrations occurred prior to construction, with lowest concentrations occurring during and after construction. During construction, TSS concentrations increased at sites immediately upstream, downstream, and adjacent to the construction area. Increased turbidity was generally restricted to areas immediately upstream and downstream of the test plug, with maximum levels occurring during the initial construction phase. Some downstream increases in turbidity were observed; however, impacts were short-term, lasting less than 24 h. Depresssed DO levels (<2 mg/l) were observed upstream of the test plug following completion of the initial plug across C-38. Dissolved oxygen levels remained low for approximately 6 weeks, with no apparent ecological impacts. Total mercury (HgT) within canal sediment ranged from 9.2–180 ng/g and methylmercury concentrations ranged from 0.037–0.708 ng/g. Concentration of total mercury and total methylmercury (MeHgT) in the backfill material were much lower than concentrations in the canal sediment. No significant change in aqueous HgT concentrations occurred over the sampling period, although construction-induced turbidity could have temporarily caused a slightly elevated concentration immediately downstream of the construction site. Methylmercury concentrations in the water column ranged from 0.033–0.518 ng/l. No significant differences in mean MeHgT concentrations occured between sites or between sampling dates, except at one downstream site where MeHgT declined significantly over the sampling period.     

The effect of the time of sampling on the compliance of bathing water in NW England with the EU Directive on bathing water quality

The ability of Morecambe’s three designated bathing waters to pass the EU Directive on Bathing Water Quality depends on the time of day when the sample is taken, the indicator organism tested for and whether the test uses the most strict (Guideline) or the least strict (Imperative) criteria. Morning and afternoon sampling for faecal coliforms, faecal streptococci and the pathogenCampylobacter was carried out monthly over the 1996 and 1997 bathing seasons. In the afternoons average faecal coliforms declined by 77% in 1996 and 87% in 1997 compared with the mornings, faecal streptococci by 79% and 83% and campylobacters by 66% and 86%. This decline in bacterial numbers between morning and afternoon was related to variations in water temperature and levels of ultraviolet radiation. All three bathing waters failed the Guideline criteria of the EU Directive on Bathing Water Quality. Using the Imperative criteria, no bathing waters passed in the mornings of either year, some passed in the afternoons of 1996 and all passed in the afternoons of 1997. The increased pass rate in 1997 coincided with improved sewage treatment, high temperatures and increased levels of sunshine. In 1997 sampling by the Environment Agency produced fewer failures than our morning sampling but more than our afternoon sampling. Their sampling was done around midday. It is suggested that where possible all sampling of EU designated bathing waters should be carried out in the early morning.     

Respiratory responses of the estuarine mysid Neomysis integer (Peracarida: Mysidacea) in relation to a variable environment

The euryhaline mysid Neomysis integer (Peracarida: Mysidacea) is a common member of the hyperbenthos of the upper reaches of European estuaries. In the East Looe River Estuary (Cornwall, England), this species experiences extensive tidal and seasonal changes in temperature (3 to 15 °C) and salinity (1 to 34‰). In this investigation, the effects of temperature (5, 10 and 15 °C) and salinity (1, 10, 20 and 30‰) on the oxygen consumption of male and female N. integer are reported, and are related to field measurements to identify the adaptive responses of the respiratory physiology to such a variable environment. The general responses were similar for each sex; however, at any given temperature/salinity combination, male N. integer consumed more oxygen than females. The general trends were increased oxygen consumption with increasing temperature (Q₁₀ values ranged from ∼1.7 to 2.5) and decreased oxygen consumption with increasing salinity. Temperature and salinity interacted at high water antagonistically to minimise changes in mysid oxygen-consumption. When related to tidal fluctuations in temperature and salinity experienced by N. integer inhabiting the East Looe River Estuary, the results reveal how the respiratory physiology of this species is adapted to its variable environment. Received: 16 June 1998 / Accepted: 15 December 1998     

青岛近海沉积物PCBs的水平与垂直分布及贝类污染

利用13C同位素内标法及气相色谱-质谱方法对青岛胶州湾内外8个表层沉积物,1个沉积物柱状岩心和2个贝类样品中包括14种共平面PCBs在内的50种PCBs同系物含量进行了测定,在所有样品中均检测出了PCBs化合物.讨论了PCBs的分布特征.表层样品以胶州湾东岸的含量最高,从北岸、西岸、胶州湾口及胶州湾外PCBs含量逐渐降低.表层沉积物中总PCBs含量在0.65～32.9ng/g dw. PCBs总含量落在国内外海洋近岸表层沉积物含量范围的中值区.表明污染来源有城市污水排放及大气来源2种,而不属于工业污染类型.多氯联苯主要以低氯取代PCBs为主,大部分高氯取代PCBs的含量低于检出限.柱状样中共平面PCBs的含量及毒性当量浓度总的垂直变化趋势是从1951年到现在逐渐减少.贝类样品的总PCBs含量为4.9～8.4ng/g dw,属低污染水平.     

CHARACTERISTICS OF LONG‐TERM FRESHWATER TRANSPORT IN APALACHICOLA BAY1

ABSTRACT: Long‐term freshwater transport is an important factor affecting estuarine aquatic ecosystems. In this study, a primitive equation, prognostic, three‐dimensional, hydrodynamic model was applied to Apalachicola Bay, Florida, for the summer and fall seasons of 1993. In response to the river freshwater discharge, tide, and wind forces, the model simulations were used to characterize the long‐term freshwater transport processes in the bay. Analysis of spatial distributions of seasonal average salinity and currents shows that the long‐term freshwater transport was strongly affected by the forcing functions of wind and density gradient in the bay. Average freshwater input was approximately the same in the summer and fall seasons of 1993. However, in the summer season, more freshwater moved to the east direction due to the predominant wind from the west, while in the fall season more freshwater moved to the west in response to the wind primarily from the east. The water column was strongly stratified near the river mouth, and it gradually changed to well mixing near the ocean boundaries. Vertical stratification in the bay changed due to wind‐induced mixing and mass transport. Due to the density gradient effect, surface residual currents carrying fresher water were in the direction from the river toward the Gulf, while the bottom residual currents with saltier water entered the bay from the Gulf of Mexico.