Seawalls as a response to coastal erosion and flooding: a case study from Grande Comore,Comoros (West Indian Ocean)

Regional Environmental Change - Many coasts are eroding. In the Comoros, as in many other small island developing states (SIDS), communities frequently respond to coastal erosion by building...     

Pinning down vulnerability: from narratives to numbers

Social vulnerability analyses have typically relied upon narratives to capture the nuances of the concept. While narratives have enhanced our understanding of the multiple drivers of vulnerability, they have had limited influence on hazards and climate adaptation policy. This is partially a function of the different needs and goals of the policy and research communities. The former prioritises generalised quantitative information, while the latter is more concerned with capturing complexity. A theoretically driven and empirically tested quantitative vulnerability and capacities index (VCI) for use at the local scale is presented to help connect vulnerability research and policy. There are four versions of the index for use in rural and urban contexts at the household and community levels. There can be an infinite number of drivers of vulnerability, but the VCI draws upon 12 indicators to represent material, institutional and attitudinal aspects of differential vulnerability and capacities.     

Use of molecular and In Silico bioinformatic tools to investigate pesticide binding to insect (Lepidoptera) phenoloxidases (PO): Insights to toxicological aspects

In the present work, the promising bioinformatic tools, based on structure–affinity analysis, allowed to screen several pesticides supposed to bind to the insect immune Phenoloxidases (PO). First, the binding of aminoparathion, a reference compound, to the PO was structurally (3D) validated in accordance with previous reports. Second, using the same docking conditions, a range of pesticides was checked for their binding ability to the crystal 3D structure (PDB 3HSS) of the insect Manduca sexta (Lepidoptera) PO. The obtained data showed that many of the tested pesticides were able to bind, in silico, to M. sexta PO. The combination of in vitro (chemical and biochemical) and in silico (automated docking) approaches was found advantageous to elucidate the behavior of phenolic pesticides as substrate-analogues when binding to the active site of insect POs. Our findings emphasize new ecotoxicological aspects of pesticide residues in the agro-chemical and environmental circles.     

Binding of aluminum to human serum transferrin,human serum albumin and rat serum proteins

Abstract

Human serum transferrin (HSTF), human serum albumin (HSA) and rat serum were compared for their interaction with AlCl₃ , in a Tris‐HCl buffer solutions (pH 7.4). The AlCl₃ was tested in series of concentrations in the range of 50 μM up to 500 μM . HSTF, HSA and their 1:1 mixture and rat serum were incubated at 37°C with series of AlCl₃ concentrations. The protein profile of the incubated solutions were compared to control using SDS‐PAGE and FPLC tests. The results indicated that HSTF was more specifically responsive to AlCl₃showing a characteristic increase in its UV absorption, peak and area dimensions. Simultaneously, HSA was less affected, but it showed a significant shift with an increase in molecular weight accompanied with a change in its profile. The respective bands of transferrin and albumin in rat serum behaved similarly. The SDS‐PAGE and FPLC data coincided and confirmed the preferential affinity of HSTF to bind with Al³⁺ . These results support the suggestion of using HSTF for monitoring levels of Al³⁺ in human blood samples of exposed population. The importance of further developing such a biomarker is the increased demand for early detection of the hazardous levels of Al³⁺ in relation to its long term neurotoxic adverse effects.     

Temporal patterns of road network development in the Brazilian Amazon

The Brazilian Amazon is a globally important ecosystem that is undergoing rapid development and land-use change. Roads are a key spatial determinant of land-use conversion and strongly influence the rates and patterns of habitat loss and represent a key component of models that attempt to predict the spatio-temporal patterns of Amazonian land-use change and the consequences of such changes. However, the spatio-temporal patterns of road network development are poorly understood and seldom quantified. Here, we used manually digitised satellite imagery at multiple temporal and spatial scales across the Brazilian Amazon to quantify and model the rate at which road networks are proliferating. We found that the road network grew by almost 17,000 km per year between 2004 and 2007. There was large spatial variation in road network density, with some municipalities having road densities as high as 0.5 km/km², and road network growth rates were highest in municipalities with an intermediate road network density. Simulations indicated that road network development within municipalities follows a logistic growth pattern through time, with most of the development occurring within a 39-year time period. This time period is similar to those of other boom and bust development dynamics observed in the Brazilian Amazon. Understanding the temporal patterns of road development will aid the development of better predictive land-use change models for the Amazon, given the key importance of roads as a predictor of deforestation in many existing models.     

Kinetics of metribuzin release from bentonite-polymer composites in water

A series of bentonite polymer-composites (BPCs) loaded with metribuzin were studied for their controlled release in aqueous medium. The release of active ingredient from BPCs was significantly lower as compared to commercial metribuzin formulation. The results revealed that the cumulative metribuzin release was highest (81%) from the BPCs containing 8% clay (commercial bentonite) and 2% metribuzin which correspond to the lowest (14 days) half-life values i.e., time required for 50% release of active ingredient (t_1/2). The metribuzin release from the BPCs decreased with increased concentration of clays in polymer matrix and the release was further decreased with BPCs prepared with pure nano-bentonite. BPCs containing 12% clay and 2% metribuzin showed maximum t_1/2 values i.e., 25 and 51 days for commercial bentonite and pure nano-bentonite as clay sources, respectively. The differential behaviour in the metribuzin release rates from BPCs was ascribed due to variations in crosslinking of metribuzin in the composites. As metribuzin release was found to be slower in BPCs compared to commercial formulation, it could be used for control of weeds tailored to different crops.     

Simulation of Surface Water for Un‐Gauged Areas with Storage‐Attenuation Wetlands1

Abstract: A nontraditional application of the Hydrological Simulation Program – FORTRAN (HSPF) model to simulate freshwater discharge to upper Charlotte Harbor along Florida’s west coast was performed. This application was different from traditional HSPF applications in three ways. First, the domain of the model was defined based on the hydraulic characteristics of the landforms using small distributed parameter discretization. Second, broad wetland land forms, representing more than 20% of this area, were simulated as reaches with storage‐attenuation characteristics and not as pervious land segments (PERLNDs). Finally, the reach flow‐tables (F‐Tables) were configured in a unique way to be calibrated representing the uncertainty of the storage‐attenuation process. Characterizing wetlands as hydrography elements allows flow from the wetlands to be treated as a stage‐dependent flux. The study was conducted for the un‐gauged portion of the Peace and Myakka rivers in west‐central Florida. Due to low gradient tidal influences, a large portion of the basin is un‐gauged. The objective of this study was to simulate stream flow discharges and to estimate freshwater inflow from these un‐gauged areas to upper Charlotte Harbor. Two local gauging stations were located within the model domain and were used for calibration. Another gauge with a shorter period of record was used for verification. A set of global hydrologic parameters were selected and tested using the parameter optimization software (PEST) during the calibration. Model results were evaluated using PEST and well‐known statistical indices. The correlation coefficients were very high (0.899 and 0.825) for the two calibration stations. Further testing of this approach appears warranted for watersheds with significant wetlands coverage.     

Maternal and cord blood levels of Aldrin and Dieldrin in Delhi population

Aldrin and dieldrin, structurally similar organochlorine pesticides belong to cyclodiene family and were widely used for agriculture and public health program in India. Although the manufacturing, use and import of aldrin and dieldrin have been banned in India since 2003, these pesticides are still persistent in environment and may be associated with adverse neurological and reproductive effects. The aim of this study is to assess the recent exposure level of aldrin and dieldrin and their placental transfer to fetus in normal healthy full-term pregnant women belonging to north Indian population undergoing normal delivery at Obstetrics and Gynecology department of UCMS and GTB hospital, Delhi. Quantitative analysis of aldrin and dieldrin residues in maternal and cord blood samples were carried out by gas chromatography system equipped with electron capture detector. The results of our study clearly revealed that maternal and cord blood levels of aldrin and dieldrin of pregnant women are age and dietary habit dependent. The aldrin level in maternal blood and dieldrin level in cord blood are higher in women in the age group 25–30 years than in women in age group of 19–24 years. Similarly, aldrin level in maternal blood is significantly higher in women with non-vegetarian dietary habit than in women with vegetarian dietary habit. No significant association is found for maternal and cord blood level. The results of the present study clearly demonstrate prenatal uptake of aldrin and dieldrin and provide recent information on the subsequent transplacental transfer.     

Microfiltration of pretreated sanitary landfill leachate

A laboratory study using a bench scale model of two units operation involving coagulation process with Moringa oleifera seeds extract as a coagulant and filtration process using hollow fibre microfiltration membrane, was adopted to treat Air Hitam Sanitary Landfill leachate in Puchong, Malaysia. The performance of the microfiltration membrane in pretreated sanitary landfill leachate treatment was investigated through a continuous process. The leachate sample was passed through conventional coagulation process before being filtered through a hollow fibre microfiltration membrane of 0.1 μm surface pores. The hollow fibre microfiltration membrane decreased the turbidity, colour, total suspended solids, total dissolved solids and volatile suspended solids in the leachate by 98.30, 90.30, 99.63, 14.71 and 20%, respectively. The results showed that microfiltration is capable of removing high percentage of solids from leachate and might be considered as a polishing stage after on-site biological treatment for sanitary landfill leachate.     

Heavy-metal distribution and risk assessment of sediment and fish from El-Mex Bay, Alexandria, Egypt

Heavy metals are increasingly being released into natural waters from geological and anthropogenic sources. The distribution of several heavy metals (Cr, Cu, Cd, Pb, Zn, and Hg) was investigated in muscle, gill, and liver in two different fish species seasonally collected in El-Mex Bay (autumn 2004-summer 2005). In order to evaluate the pollution status of the Bay, the concentrations of the selected metals in the labile and total fractions were analysed in sediment samples collected from eight sites in El-Mex Bay during autumn 2004. Also, the Index of Geoaccumulation (I_geo) for the sediment was estimated. The total and labile fractions of the selected metals in sediment samples were 15.2 and 62.8 μg g^-1 dw for Cu, 1.8 and 5.0 μg g^-1 dw for Cd, 79.1 and 130.3 μg g^-1 dw for Zn, 0.2 and 1.2 μg g^-1 dw for Hg, 35.8 and 93.0 μg g^-1 dw for Pb, and 13.9 and 31.0 μg g^-1 dw for Cr. The concentrations of all metals were lower in flesh than those recorded in liver and gill due to their physiological roles. The metal pollution index for fish was calculated. Health hazard calculations for the contaminated sediments and fish consumption were calculated to evaluate the effect of pollution on health.