Limitations of habitats as biodiversity surrogates for conservation planning in estuaries

Increasing pressures on global biodiversity and lack of data on the number and abundance of species have motivated conservation planners and researchers to use more readily available information as proxies or surrogates for biodiversity. “Habitat” is one of the most frequently used surrogates but its assumed value in marine conservation planning is not often tested. The present study developed and tested three alternative habitat classification schemes of increasing complexity for a large estuary in south-east Australia and tested their effectiveness in predicting spatial variation in macroinvertebrate biodiversity and selecting estuarine protected areas to represent species. The three habitat classification schemes were: (1) broad-scale habitats (e.g., mangroves and seagrass), (2) subdivision of each broad-scale habitat by a suite of environmental variables that varied significantly throughout the estuary, and (3) subdivision of each broad-scale habitat by the subset of environmental variables that best explained spatial variation in macroinvertebrate biodiversity. Macroinvertebrate assemblages differed significantly among the habitats in each classification scheme. For each classification scheme, habitat richness was significantly correlated with species richness, total density of macroinvertebrates, assemblage dissimilarity, and summed irreplaceability. However, in a reserve selection process designed to represent examples of each habitat, no habitat classification scheme represented species significantly better than a random selection of sites. Habitat classification schemes may represent variation in estuarine biodiversity; however, the results of this study suggest they are inefficient in designing representative networks of estuarine protected areas.     

Alteration of body total antioxidant capacity and thiol molecules in human chronic exposure to aluminum

The physiological role of aluminum (Al) is not yet known. Exposure to Al may cause many human disorders. The aim of this study was to explore how occupational human exposure to Al might affect the body oxidative stress. The relation between Al toxicity and oxidative stress was studied in blood samples obtained from 45 primary Al production workers, with a minimum work history of three years in the age range of 29–52 years. They were evaluated for oxidative stress biomarkers including thiobarbituric acid reactive substances (TBARS) indicator of lipid peroxidation, ferric reducing ability of plasma (FRAP) indicator of total antioxidant capacity, total thiol molecules and Al level in blood. The results showed that workers have significantly higher blood Al levels and concomitant lower blood FRAP and total thiol molecules in comparison to controls. Smokers had lower total thiol molecules than non-smokers. The subjects who had a previous history of disease had lower FRAP levels. It is concluded that Al induces oxidative stress in primary Al production workers. Supplementation of workers with antioxidants may have beneficial effects.     

Determination of ultra-trace amounts of cadmium by ET-AAS after column preconcentration with a new sorbent of modified MWCNTs

The present research reports on the application of modified multiwalled carbon nanotubes as a new, easily prepared, and stable solid sorbent for the column preconcentration of ultra-trace amounts of cadmium in aqueous solution. Multiwalled carbon nanotubes were oxidized with concentrated HNO₃ and modified with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol and then were used as a solid phase for the column preconcentration of Cd(II). Elution was carried out with 0.5 mol?L^?1 HNO₃. The amount of eluted Cd(II) was measured using electrothermal atomic absorption spectrometry. Various parameters such as pH, sample and eluent flow rate, eluent concentration, breakthrough volume, and interference of a great number of anions and cations on the retention of analyte on sorbent were studied. Under the optimized conditions, the calibration graph was linear in the range of 0.67 ng?L^?1 to 5.0 μg?L^?1 and the detection limit (3S_b, n?=?7) was 0.14 ng?L^?1 in initial solution. A preconcentration factor of 300 and relative standard deviations of ±3.6 % for seven successive determinations of 3 ng of Cd(II) were achieved. The column preconcentration was successfully applied to the analysis of river water, waste water, and Persian Gulf water sample.     

Organochlorine contaminants in the hair of Iranian pregnant women

In the present study, the hair of pregnant women was sampled between November 2007 and January 2008 in Ahvaz and Noushahr cities and the countryside of Noushahr, Iran. They were analyzed for organochlorine pesticides (OCPs), such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), α-, β-, and γ-hexachlorocyclohexane (HCH) isomers and seven polychlorinated (PCBs) congeners (IUPAC Nos. 28, 52, 101, 118, 138, 153 and 180). Significant differences between the concentrations of investigated pollutants were found between the locations (p < 0.05). For HCHs, the γ-HCH isomer was measured at higher mean concentrations (6 ng g⁻¹ hair) compared to the β-HCH isomer (0.03 ng g⁻¹), which generally is the most prevalent HCH in biological matrices. Very high mean concentrations of p,p′-DDT in countryside of Noushahr (24 ng g⁻¹) combined with lower values (0.6) of ratio p,p′-DDE/p,p′-DDT in the hair samples suggest recent exposure to “fresh” DDT in this region. Significant differences in OCPs and PCBs were found between primiparous and multiparous mothers (p < 0.05). There was no correlation between levels of OCPs and PCBs in the hair of Iranian pregnant women and their age. There was a significant difference (p < 0.05) in the organochlorine levels, including HCHs, between mothers who have eaten fish once a week and those who consumed fish more than once per week in Noushahr.     

River water quality management under incomplete information: application of an N-person iterated signaling game

One of the important issues in river quality management is to provide pollution control strategies which are acceptable for all stakeholders. When there is only one water quality checkpoint in a reach of a river which receives pollution loads of several dischargers and dischargers are penalized for any water quality violation, the game theory can be used for modeling the natural process of bargaining among load dischargers considering the assimilative capacity of a river. There are also some types of uncertainties in river water quality management which should be incorporated throughout the bargaining process. Signaling games can be utilized for modeling the bargaining among dischargers and developing perfect Bayesian equilibrium (PBE) strategies for pollution control. In this paper, a new methodology called N-person iterated signaling game is developed for river quality management considering the existing uncertainties in pollution loads of dischargers. The methodology can provide the stable PBE waste load allocation strategies. The practical utility of the proposed methodology is illustrated by applying it to a reach of the Zarjub River in Iran. This reach includes seven pollution load dischargers.     

Determining the most suitable areas for artificial groundwater recharge via an integrated PROMETHEE II-AHP method in GIS environment (case study: Garabaygan Basin, Iran)

Flood spreading is a suitable strategy for controlling and benefiting from floods. Selecting suitable areas for flood spreading and directing the floodwater into permeable formations are amongst the most effective strategies in flood spreading projects. Having combined geographic information systems (GIS) and multi-criteria decision analysis approaches, the present study sought to locate the most suitable areas for flood spreading operation in the Garabaygan Basin of Iran. To this end, the data layers relating to the eight effective factors were prepared in GIS environment. This stage was followed by elimination of the exclusionary areas for flood spreading while determining the potentially suitable ones. Having closely examined the potentially suitable areas using the Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE) II and analytic hierarchy process (AHP) methods, the land suitability map for flood spreading was produced. The PROMETHEE II and AHP were used for ranking all the alternatives and weighting the criteria involved, respectively. The results of the study showed that most suitable areas for the artificial groundwater recharge are located in Quaternary Q_g and Q^gsc geologic units and in geomorphological units of pediment and Alluvial fans with slopes not exceeding 3 %. Furthermore, significant correspondence between the produced map and the control areas, where the flood spreading projects were successfully performed, provided further evidence for the acceptable efficiency of the integrated PROMETHEE II-AHP method in locating suitable flood spreading areas.     

Characteristics of surface layer turbulence in coastal area of Qatar

A characterization of the atmospheric surface layer in coastal region of Qatar is presented in the present paper. The micrometeorological data is collected in the New Doha International Airport (25.25N, 51.62E), at a pier 500 m into the ocean by deploying tower based instruments during the month of June-2011. The normalized variance of the three components of velocity and temperature are studied within the framework of Monin–Obukhov similarity theory. The normalized variances of stream wise and transverse velocity at near-neutral condition are found to be consistent with the reported values from measurement sites around the world, but the normalized variance of vertical velocity at near-neutral condition is found to be consistently lower in the present case. The dependency of the normalized velocity variances with buoyancy parameter indicates a higher growth rate of variances, compared to other investigations. The non-dimensional variance of temperature matches well with the past investigations, but the correlation between vertical velocity and temperature indicates higher magnitude for the present location.     

Environmental risks of farmed and barren alkaline coal ash landfills in Tuzla, Bosnia and Herzegovina

The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH ( approximately 12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were <2microgl(-1) whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44microgl(-1)). The opposite pattern was found for Cr likely due to large initial leaching of CrVI. Public use of landfills, including farming, should be based on a prior risk assessment due to the heterogeneity of CCR.     

Comparison of first-order-decay modeled and actual field measured municipal solid waste landfill methane data

The first-order decay (FOD) model is widely used to estimate landfill gas generation for emissions inventories, life cycle assessments, and regulation. The FOD model has inherent uncertainty due to underlying uncertainty in model parameters and a lack of opportunities to validate it with complete field-scale landfill data sets. The objectives of this paper were to estimate methane generation, fugitive methane emissions, and aggregated collection efficiency for landfills through a mass balance approach using the FOD model for gas generation coupled with literature values for cover-specific collection efficiency and methane oxidation. This study is unique and valuable because actual field data were used in comparison with modeled data. The magnitude and variation of emissions were estimated for three landfills using site-specific model parameters and gas collection data, and compared to vertical radial plume mapping emissions measurements. For the three landfills, the modeling approach slightly under-predicted measured emissions and over-estimated aggregated collection efficiency, but the two approaches yielded statistically equivalent uncertainties expressed as coefficients of variation. Sources of uncertainty include challenges in large-scale field measurement of emissions and spatial and temporal fluctuations in methane flow balance components (generated, collected, oxidized, and emitted methane). Additional publication of sets of field-scale measurement data and methane flow balance components will reduce the uncertainty in future estimates of fugitive emissions.     

Quantification of PAHs and chlorinated compounds by novel solid-phase microextraction based on the arrays of tin oxide nanorods

The results of an innovative study on a new and highly efficient stationary phase based on the SnO₂ nanorods coating on fused silica have been reported in this paper. SnO₂ nanorods have been grown on fused silica fibers using a hydrothermal process. The extraction properties of the fiber were investigated using headspace solid-phase microextraction (HS-SPME) mode coupled with gas chromatography–mass spectrometry detection for 1,4-dichloro-2-nitrobenzene, biphenyl, and acenaphthene. The effect of different variables on extraction efficiency was studied simultaneously using Box–Behnken method as experimental design. The variables of interest in the HS-SPME were salt effect, adsorption temperature, extraction, and desorption time. Under optimal conditions, the calibration curves were linear up to 10²–10⁵ ng?L^?1 (R ²?>?0.998) with detection limits of 10^?3, 10^?1, and 10 ng?L^?1 for acenaphthene, biphenyl, and 1,4-dichloro-2-nitrobenzene, respectively. The relative standard deviations for single fiber and fiber to fiber were less than 9.8 and 12.5 %, respectively. The high stability of the SnO₂ nanostructure coating is proved at relatively high temperatures (up to 300 °C) with a high extraction capacity and long lifespan (more than 100 times). By applying the proposed technique, promising recoveries (93–98 %) were obtained in the analysis of environmental water samples.