A free-enzyme catalyst for the bioremediation of environmental atrazine contamination

Herbicide contamination from agriculture is a major issue worldwide, and has been identified as a threat to freshwater and marine environments in the Great Barrier Reef World Heritage Area in Australia. The triazine herbicides are of particular concern because of potential adverse effects, both on photosynthetic organisms and upon vertebrate development. To date a number of bioremediation strategies have been proposed for triazine herbicides, but are unlikely to be implemented due to their reliance upon the release of genetically modified organisms. We propose an alternative strategy using a free-enzyme bioremediant, which is unconstrained by the issues surrounding the use of live organisms. Here we report an initial field trial with an enzyme-based product, demonstrating that the technology is technically capable of remediating water bodies contaminated with the most common triazine herbicide, atrazine.     

Sampling animal association networks with the gambit of the group

Ecologists increasingly use network theory to examine animal association patterns. The gambit of the group (GoG) is a simple and useful assumption for accumulating the data necessary for a network analysis. The gambit of the group implies that each animal in a group is associating with every other individual in that group. Sampling is an important issue for networks in wild populations collected assuming GoG. Due to time, effort, and resource constraints and the difficulty of tracking animals, sampled data are usually a subset of the actual network. Ecologists often use association indexes to calculate the frequency of associations between individuals. These indexes are often transformed by applying a filter to produce a binary network. We explore GoG sampling using model networks. We examine assortment at the level of the group by a single dichotomous trait, along with many other network measures, to examine the effect of different sampling regimes, and choice of filter on the accuracy and precision with which measures are estimated. We find strong support for the use of weighted, rather than filtered, network measures and show that different filters have different effects depending on the nature of the sampling. We make several practical recommendations for ecologists planning GoG sampling.     

The impact of urbanization on tropical mangroves (Fortaleza,Brazil): Evidence from PAH distribution in sediments

This investigation represents the first environmental diagnosis of the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments from a tropical mangrove in Fortaleza, northeastern Brazil. Sediment cores from six sampling stations in the Cocó and Ceará Rivers were retrieved in June-July 2006 to determine 17 priority PAHs. The total PAH concentrations (Σ_PAHs) ranged from 3.04 to 2234.76 μg kg^?1(Cocó River) and from 3.34 to 1859.21 μg kg^?1 (Ceará River). These levels are higher than those of other cities with more industrial development. PAH concentrations did not reach probable effect levels (PELs). However, from 4.5 to 87.5% of individual PAH concentrations can occasionally cause adverse biological effects for aquatic organisms. The PAH molecular ratios indicate that the PAHs in the sediment core were derived mainly from petroleum, wood, and charcoal combustion (pyrogenic source), and that atmospheric deposition and urban runoff may serve as important pathways for PAH input to the sediment. Clearly, the Σ_PAHs in sediments collected in the Cocó and Ceará Rivers indicate that ongoing pollution is more severe than past pollution.     

A performance evaluation of the National Air Quality Forecast Capability for the summer of 2007

This paper provides a performance evaluation of the real-time, CONUS-scale National Air Quality Forecast Capability (NAQFC) that supported, in part, its transition into operational status. This evaluation focuses primarily on discrete forecasts for the maximum 8-h O₃ concentrations covering the 4-month period, June through September, 2007, using measurements obtained from EPA's AIRNow network. Results indicate that the 2007 NAQFC performed as well or better than previous configurations, despite the expansion of the forecast domain into the western half of the nation that is dominated by complex terrain. The mean, domain-wide, season-long correlation was 0.70. When examined over time, the domain-wide correlations exhibit a fairly consistent nature, with values exceeding 0.60 (0.70) over 90% (55%) of the days. The NAQFC systematically over-predicted the 8-h O₃ concentrations, continuing a trend established by earlier NAQFC configurations, though to a lesser degree. The summer-long mean forecast value of 53.2 ppb was 4.2 ppb higher than the observed value, resulting in a domain-wide Normalized Mean Bias (NMB) of 8.7%. Most of the over-prediction is associated with observed concentrations less than 50 ppb. In fact the model tends to under-predict when concentrations exceed 70 ppb. As with the bias, the error associated with the latest configuration was also lower. The summer-long Root Mean Square Error of 13.0 ppb (Normalized Mean Error (NME) = 20.4%) represented marked improvements over earlier forecasts. Examination of the spatial distribution of both the NMB and NME reveals that the NAQFC was generally within 25% for the NME and 25% for the NMB over a majority of the domain. Several areas of poorer performance, where the NMB and NME often exceed 25% and in some cases 50%, were noted. These areas include southern California, where the NAQFC tended to under-predict concentrations (especially on weekends) and the southeast Atlantic and Gulf coasts regions, where the model over-predicted. Subsequent analysis revealed that the incorrect temporal allocation of precursor emissions was likely the source of the under-prediction in southern California, while inaccurate simulation of PBL heights likely contributed to the over-prediction in the coastal regions.     

Genetic considerations in the prenatal diagnosis of overgrowth syndromes

Large (>90%) for gestational age (LGA) fetuses are usually identified incidentally. Detection of the LGA fetus should first prompt the provider to rule out incorrect dates and maternal diabetes. Once this is done, consideration should be given to certain overgrowth syndromes, especially if anomalies are present. The overgrowth syndromes have significant clinical and molecular overlap, and are associated with developmental delay, tumors, and other anomalies. Although genetic causes of overgrowth are considered postnatally, they are infrequently diagnosed prenatally. Here, we review prenatal sonographic findings in fetal overgrowth syndromes, including Pallister-Killian, Beckwith-Wiedemann, Sotos, Perlman, and Simpson-Golabi-Behmel. We also discuss prenatal diagnosis options and recurrence risks. Copyright © 2009 John Wiley & Sons, Ltd.     

Attitudes and behaviour towards waste management in the Dublin,Ireland region

The hypothesis of this research was that attitudes about the management of biodegradable municipal waste (BMW) are spatially variable, even within a city of modest (1.2 million) population. For a select number of representative electoral districts in the Dublin, Ireland region, residents were surveyed regarding attitudes towards waste management in general, and BMW management in particular. A total of 850 survey responses were collected. Door-to-door interviews produced 688 responses in the residential sector; these were supplemented by 162 responses to a web-based survey.The surveys revealed that the majority of households use local authority, rather than private, waste collection services (both are available). The majority of residents, regardless of the local authority in which they live, were satisfied with their waste management service. “Reducing the quantity of waste generated” was regarded the most important future issue for 28% of residential respondents. Statistical analyses of the survey responses showed that the local authority in which respondents resided significantly influenced most responses (including waste collection service used, waste service satisfaction and backyard composting activity). Many responses (including waste service satisfaction, waste management influences) were also significantly related to the respondents’ personal characteristics (e.g., education level, type of accommodation, age, etc.). These statistical results proved the hypothesis of the research and demonstrated that waste management initiatives designed for one area of the city (or, indeed, for uniform application to the city as a whole) could ignore the needs of other areas. The survey responses suggest that targeted intervention strategies would lead to improved diversion rates of BMW from landfill, a requirement of the Landfill Directive 1999/31/EC.     

Understanding the chemical and mineralogical properties of the inorganic portion of MSWI bottom ash

This paper investigates the changes of mineralogical composition of bottom ash in the environment. The chemical and mineralogical bulk composition was determined by X-ray fluorescence (XRF) and X-ray powder diffraction (XRPD) Rietveld method. Single bottom ash particles were investigated by optical microscopy, scanning electron microscopy with quantitative energy-dispersive X-ray microanalysis (SEM/EDX) and electron probe micro analysis (EPMA). SEM/EDX and EPMA are valuable complement to bulk analysis and provide means for rapid and sensitive multi-elemental analysis of ash particles. The fresh bottom ash consists of amorphous (>30 wt.%) and major crystalline phases (>1 wt.%) such as silicates, oxides and carbonates. The mineral assemblage of the fresh bottom ash is clearly unstable and an aging process occurs by reaction towards an equilibrium mineral phase composition in the environmental conditions. The significant decrease of anhydrite and amorphous contents was observed in the aged bottom ash, leading to the formation of ettringite, hydrocalumite and rosenhahnite under atmospheric conditions. In the water-treated sample, the calcite contents increased significantly, but ettringite was altered by the dissolution and precipitation processes in part, to produce gypsum, while the remaining part reacted with chloride to form hydrocalumite. Gypsum and other Ca based minerals may take up substantial amounts of heavy metals and subsequently control leaching behaviour of bottom ash.     

Habitat type-based bioaccumulation and risk assessment of metal and As contamination in earthworms, beetles and woodlice

The present study investigated the contribution of environmental factors to the accumulation of As, Cd, Cu, Pb and Zn in earthworms, beetles and woodlice, and framed within an exposure assessment of the European hedgehog. Soil and invertebrate samples were collected in three distinct habitat types. Results showed habitat-specific differences in soil and invertebrate metal concentrations and bioaccumulation factors when normalized to soil metal concentration. Further multiple regression analysis showed residual variability (habitat differences) in bioaccumulation that could not be fully explained by differences in soil metal contamination, pH or organic carbon (OC). Therefore, the study demonstrated that in bioaccumulation studies involving terrestrial invertebrates or in risk assessment of metals, it is not sufficient to differentiate habitat types on general soil characteristics such as pH and/or OC alone. Furthermore, simple generic soil risk assessments for Cd and Cu showed that risk characterization was more accurate when performed in a habitat-specific way.