Prioritisation of abstraction boreholes at risk from chlorinated solvent contamination on the UK Permo-Triassic Sandstone aquifer using a GIS

A 250 km(2) area of the Permo-Triassic Sandstone aquifer in the West Midlands of England, UK, was selected as a test region for the development of a geographic information system (GIS)-based risk assessment methodology that incorporates contaminant source, groundwater vulnerability and groundwater abstraction catchment elements in order to prioritise areas and boreholes potentially at risk from chlorinated solvent pollution on a regional scale. Factors incorporated in the vulnerability assessment include the nature of soils, presence or absence of superficial or glacial deposits, fault density and depth to water table. ARCVIEW GIS was employed with a simple ranking system from which the derived vulnerability assessment index was combined with current chlorinated solvent user industry data and source protection zone components. Results indicate the presence of high-risk areas in urban locations where locally dense distributions of chlorinated solvent user industries combine with high vulnerability aquifers within the catchment of supply boreholes. Ranking of catchment-specific risk reveals the abstraction points under greatest stress. The proposed methodology has applications as a regional-scale initial screening tool to guide site selection for regulatory inspections and assist in prioritising monitoring strategies for existing boreholes. Future developments will provide guidance for locating new urban boreholes in areas of lowest risk

Borehole Optimisation System (BOS) — a GIS based risk analysis tool for optimising the use of urban groundwater

The recognition that urban groundwater is a potentially valuable resource for potable and industrial uses due to growing pressures on perceived less polluted rural groundwater has led to a requirement to assess the groundwater contamination risk in urban areas from industrial contaminants such as chlorinated solvents. The development of a probabilistic risk based management tool that predicts groundwater quality at potential new urban boreholes is beneficial in determining the best sites for future resource development. The Borehole Optimisation System (BOS) is a custom Geographic Information System (GIs) application that has been developed with the objective of identifying the optimum locations for new abstraction boreholes. BOS can be applied to any aquifer subject to variable contamination risk. The system is described in more detail by Tait et al. [Tait, N.G., Davison, J.J., Whittaker, J.J., Lehame, S.A. Lerner, D.N., 2004a. Borehole Optimisation System (BOS) - a GIs based risk analysis tool for optimising the use of urban groundwater. Environmental Modelling and Software 19, 1111-1124]. This paper applies the BOS model to an urban Permo-Triassic Sandstone aquifer in the city centre of Nottingham, UK. The risk of pollution in potential new boreholes from the industrial chlorinated solvent tetrachloroethene (PCE) was assessed for this region. The risk model was validated against contaminant concentrations from 6 actual field boreholes within the study area. In these studies the model generally underestimated contaminant concentrations. A sensitivity analysis showed that the most responsive model parameters were recharge, effective porosity and contaminant degradation rate. Multiple simulations were undertaken across the study area in order to create surface maps indicating areas of low PCE concentrations, thus indicating the best locations to place new boreholes. Results indicate that northeastern, eastern and central regions have the lowest potential PCE concentrations in abstraction groundwater and therefore are the best sites for locating new boreholes. These locations coincide with aquifer areas that are confined by low permeability Mercia Mudstone deposits. Conversely southern and northwestern areas are unconfined and have shallower depth to groundwater. These areas have the highest potential PCE concentrations. These studies demonstrate the applicability of BOS as a tool for informing decision makers on the development of urban groundwater resources

A novel semiconductor-on-metal MSM photodetector design for dark current reduction

A novel design of semiconductor-on-metal MSM photodetector for reducing dark current is reported. Leakage of 11.6μA and responsivity of 2mA/W is shown, while conventional metal-on-semiconductor design shows leakage of 166μA, and responsivity of 2.5mA/W

Hafnium silicate gate insulators in field effect sensors used to detect DNA hybridization

Field-effect sensors with hafnium silicate gate insulators were fabricated following standard CMOS processes and compatible post-processes. The floating gates were functionalized with glycidoxypropyltrimethoxy silane and amine-terminated oligonucleotide probes. The pH sensitivity of the silicate surface decreased from 31.4 mV/pH to 24.6 mV/pH after functionalization due to passivation of a significant fraction of the amphoteric proton binding sites. A threshold voltage shift of 33 mV was observed as the buffer solution concentration changed from 0.015 M to 0.3 M after DNA probe molecule attachment. The hybridization caused a net increase in this shift of 3mV. With the help of a model which includes the solution of the Poisson-Boltzmann and proton site-binding at the gate, methods of achieving higher sensitivity are discussed.Peer reviewed: YesNRC publication: Ye

Determinação de elementos essenciais e não essenciais em palmito de pupunheira Determination of essential and non-essential elements in palm heart of peach palm

Considerando-se a atual situação epidemiológica do Brasil em que a obesidade e as doenças crônico-degenerativas (doenças cardiovasculares, diabetes mellitus e câncer) passam a ser destaque em saúde pública, parece prudente a preocupação quanto à caracterização química dos alimentos regionais com potencial econômico e nutricional, em especial os de baixo teor calórico, como o palmito. Sendo assim, determinou-se a composição centesimal, fitato e elementos minerais (macro e micro) no palmito de pupunheira in natura e cozido. O palmito de pupunheira utilizado foi o da raça Pampa Hermosa, da Estação Experimental de Fruticultura da Coordenação de Pesquisas em Ciências Agronômicas (CPCA) do Instituto Nacional de Pesquisas da Amazônia (INPA), em Manaus (AM), coletado no período chuvoso, em janeiro de 1995. Tomou-se aleatoriamente 3,5 kg de palmito de 110 progênies de pupunha inerme, com 2 anos de idade, por ocasião do primeiro corte. As palmeiras foram cultivadas em Latossolo Amarelo, isento de adubação. As análises químicas foram efetuadas no Laboratório de Nutrição e Físico-Química dos Alimentos do INPA e IPEN-CNEN. De acordo com os resultados obtidos, verificou-se que o palmito, in natura e cozido, apresentou em 100g da parte comestível respectivamente, alto teor de umidade, em torno de 90%; 1,5 g de proteínas; baixo teor de lipídio (0,3 e 0,2 g) e; concentrações importantes de fibra alimentar (3,8 e 2,2 g). Em relação aos elementos minerais nutricionalmente importantes sobressairam, também em 100g da parte comestível, K (194,0 mg; 128,0 mg); Ca (42,4 mg ; 42,9 mg); Mg (3,4 mg; 2,2 mg); Fe (237,7 µg; 265,2 µg), Se (2,1 µg; 2,8 µg), respectivamente no palmito in natura e cozido. Dos elementos minerais não essenciais na alimentação, destacaram-se o bromo (830,4 ±5,8 µg%; 434±5,8 µg%) e o rubídio (315,2±3,2 µg%; 433,5±34,0 µg%) respectivamente para palmito in natura e cozido. A concentração de fitato (hexafosfato de mioinositol) foi de 554,7 mg% para o palmito in natura e 379,1 mg%, para o palmito cozido. Apesar do palmito ser um alimento dietético sob o ponto de vista nutricional, devido à baixa concentração em calorias e à presença de fibra, o mesmo pode contribuir no aporte de minerais essenciais na alimentação da população Amazônica.<br>In recent years, there has been a steady increase in the ocurrence of obesity and chronic or degenerative diseases (cardiovascular, diabetes mellitus, cancer) in Brazil. Therefore, studies on the nutritional composition of regional foodstuffs, especially those with low calorific content and high commercial value, are highly justified. The aim of this study was to evaluate the centesimal phytate and mineral micro or macroelement composition of in natura or cooked palm heart of peach palm (Pampa Hermosa race), collected in January 1995 (rainy season) in the fruit experimental station of the Coordenação de Pesquisas em Ciências Agronômicas (CPCA), Instituto Nacional de Pesquisas da Amazônia (INPA), in Manaus, Brazil. Chemical analyses were conducted on a total of 3.5 kg of plant heart samples, taken at random from 110 spineless progeny from Yurimáguas, Peru, which were grown on non-fertilized soil. Analyses were conducted in the Nutrition and Food Physico-Chemical laboratory of INPA and IPEN-CNEN. Each 100 g of the edible part of in natura or cooked palm heart provided low concentrations of lipids (0.3 and 0.2 g, respectively) and high concentrations of fibre (3.8 and 2.2, respectively). Both type of palm heart contained (in 100 g): 90% humidity and 1.5 g protein. The results for nutritionally important minerals were as follows (in 100 g of in natura or cooked palm heart, respectively): K (194.0 mg; 128.0 mg), Ca (42.4 mg; 42.9 mg), Mg (3.4 mg; 2.2 mg), Fe (237.7 µg; 265.2 µg), and Se (2.1 µg: 2.8 µg). The concentrations of non essential elements minerals in in natura and cooked palm heart were, respectively, as follows: bromine (830.4±5.8 µg%; 434.0±5.8 µg%) and rubidium (315.2±3.2 µg%; 433.5±34.0 µg%). The concentration of phytate in 100 g of palm heart, was as follows: 554.7 mg (in natura) 379.1 mg (cooked). Although palm heart can be considered a dietetic foodstuff, being rich in fibre and low in calories, it can be recommended as a good source of minerals for the Amazonian populations