Prenatal exposure to mercury in a prospective mother-infant cohort study in a Mediterranean area, Valencia, Spain

BACKGROUND: Mercury (Hg) is a ubiquitous pollutant that negatively affects fetal and child neurodevelopment at accidental high-dose exposure. Some studies indicate that Mediterranean populations could be at risk of prenatal exposure to mercury through fish consumption. OBJECTIVES: To assess the prenatal exposure to total mercury (T-Hg), both inorganic and organic, in newborns by analyzing the T-Hg concentration in cord blood, and to evaluate the role of maternal fish consumption in this exposure. METHODS: In the context of a multi-center project (INMA project), a prospective birth cohort was set up in Valencia, Spain, from 2005 to 2006. A total of 253 newborns were included in this study. We compared cord blood T-Hg concentration by levels of fish intake assessed by a food frequency questionnaire completed at 28-32 weeks of gestation. Maternal covariates were obtained through a questionnaire. RESULTS: The geometric mean of T-Hg at birth was 9.9 microg/L (95% CI: 9.0, 10.8). Seventy five percent of cord blood samples were above the estimated level assumed to be without appreciable harm (5.8 microg/L). Women who consumed a portion of large oily fish, lean fish, or mixed fried fish two or more times per week had mean cord blood levels 1.6, 1.4 and 1.3 times higher, respectively, than those who rarely or never consumed fish. Other factors such as the mother's age, country of origin, smoking and season of delivery were also significantly and independently associated with cord blood T-Hg concentrations. CONCLUSIONS: Newborns from a Mediterranean area presented elevated levels of T-Hg in cord blood. Higher concentrations of T-Hg were related to maternal fish intake, particularly in the case of large oily fish species.     

Flood risk assessment and mapping in peri-urban Mediterranean environments using hydrogeomorphology. Application to ephemeral streams in the Valencia region (eastern Spain)

This paper proposes a methodology for mapping flood risk in ephemeral streams, based on assessing flood hazards and global exposure. The method has been applied to the peri-urban area of Valencia, extended over the floodplains of the Barranco del Carraixet and Rambla de Poyo catchments. Hazard was assessed using hydrogeomorphological methods. Global exposure was estimated as a combination between the economic value of land use and human exposure, following a previous study carried out by Camarasa, A.M., López, M.J. and Soriano, J., 2011. Mapping temporally variable exposure to flooding in small Mediterranean basins using land-use indicators, Applied Geography 31 (19), 136-145. Synthesis mapping was elaborated to spatially rank flood risks, in terms of their hazard and exposure components. The method is simple, effective and easily comparable. The results reveal diverse risk configurations for each floodplain, even though both are in the vicinity of Valencia city (metropolitan area). This flood risk mapping method is very useful for land use planning because it enables swift diagnosis of the nature of risks and can supports decision making by risk managers and urban planners.     

Productivity of wastewater treatment plants in the Valencia Region of Spain

This study analyses the evolution of productivity over the 2008–2012 period for a homogenous set of 199 wastewater treatment plants that are located in the Valencia Region of Spain and utilize the same treatment technology, using the smoothed bootstrap Malmquist productivity index based on Data Envelopment Analysis (DEA). The results reveal a negative trend in productivity that is mainly the result of resource management rather than an inappropriate level of innovation or use of new technologies. In addition, the effect of exogenous factors on productivity is analysed using the Kruskal-Wallis (KW) test, finding that productivity levels were affected by the quality of the influent water and the size of the plants, but not by the other factors considered.     

Using a linked soil model emulator and unsaturated zone leaching model to account for preferential flow when assessing the spatially distributed risk of pesticide leaching to groundwater in England and Wales

Although macropore flow is recognized as an important process for the transport of pesticides through a wide range of soils, none of the existing spatially distributed methods for assessing the risk of pesticide leaching to groundwater account for this phenomenon. The present paper presents a spatially distributed modelling system for predicting pesticide losses to groundwater through micro- and macropore flow paths. The system combines a meta version of the mechanistic, dual porosity, preferential flow pesticide leaching model MACRO (the MACRO emulator), which describes pesticide transport and attenuation in the soil zone, to an attenuation factor leaching model for the unsaturated zone. The development of the emulator was based on the results of over 4000 MACRO model simulations. Model runs describe pesticide leaching for the range of soil types, climate regimes, pesticide properties and application patterns in England and Wales. Linking the MACRO emulator to existing spatial databases of soil, climate and compound-specific loads allowed the prediction of the concentration of pesticide leaching from the base of the soil profile (at 1 m depth) for a wide range of pesticides. Attenuation and retardation of the pesticide during transit through the unsaturated zone to the watertable was simulated using the substrate attenuation factor model AQUAT. The MACRO emulator simulated pesticide loss in 10 of 12 lysimeter soil-pesticide combinations, for which pesticide leaching was shown to occur and also successfully predicted no loss from 3 soil-pesticide combinations. Although the qualitative aspect of leaching was satisfactorily predicted, actual pesticide concentrations in leachate were relatively poorly predicted. At the national scale, the linked MACRO emulator/AQUAT system was found to predict the relative order of, and realistic regional patterns of, pesticide leaching for atrazine, isoproturon, chlorotoluron and lindane. The methodology provides a first-step assessment of the potential for pesticide leaching to groundwater in England and Wales. Further research is required to improve the modelling concept proposed. The system can be used to refine regional groundwater monitoring system designs and sampling strategies and improve the cost-effectiveness of the measures needed to achieve 'good status' of groundwater quality as required by the Water Framework Directive.     

Indoor and outdoor air concentrations of BTEX and determinants in a cohort of one-year old children in Valencia, Spain

BTEX is the commonly used term for a group of toxic compounds (benzene, toluene, ethyl benzene, ortho-xylene and meta- and para-xylene), some of which, most notably benzene, are known carcinogens. The aim of this study is to measure the BTEX levels both inside and outside the homes of 352 one-year old children from the Valencia cohort of the INMA study (Spain) and to analyze the determinants of these levels. Passive samplers were used to measure BTEX levels during a 15 day period and a questionnaire was administered to gather information on potentially associated factors (sociodemographics, residential conditions, and lifestyle). The average concentrations of benzene, toluene, ethyl benzene, ortho-xylene, and meta- and para-xylene were 0.9, 3.6, 0.6, 0.6, and 1.0 μg/m³, respectively. On average, the indoor levels of all the compounds were approximately 2.5 times higher than those observed outdoors. Factors associated with higher BTEX concentrations inside the home were being the child of a mother of non-Spanish origin, living in a house that had been painted within the last year, living in an apartment, and not having air conditioning. Higher outdoor concentrations of BTEX depend on the residence being situated in a more urban zone, being located within the city limits, having living in a building with more than one story, residing in an area with a greater frequency of traffic, and the season of the year in which the sample was taken. The data thus obtained provide helpful information not only for implementing measures to reduce exposure to these pollutants, but also for evaluating the relation between such exposure and possible health risks for the children in the cohort.     

Eco-SpaCE: An object-oriented, spatially explicit model to assess the risk of multiple environmental stressors on terrestrial vertebrate populations

Wildlife organisms are exposed to a combination of chemical, biological and physical stressors. Information about the relative impact of each stressor can support management decisions, e.g., by the allocation of resources to counteract those stressors that cause most harm. The present paper introduces Eco-SpaCE; a novel receptor-oriented cumulative exposure model for wildlife species that includes relevant ecological processes such as spatial habitat variation, food web relations, predation, and life history. A case study is presented in which the predicted mortality due to cadmium contamination is compared with the predicted mortality due to flooding, starvation, and predation for three small mammal species (Wood mouse, Common vole, and European mole) and a predator (Little owl) living in a lowland floodplain along the river Rhine in The Netherlands. Results indicated that cadmium is the principal stressor for European mole and Little owl populations. Wood mouse and Common vole population densities were mainly influenced by flooding and food availability. Their estimated population sizes were consistent with numbers reported in literature. Predictions for cadmium accumulation and flooding stress were in agreement with field data. The large uncertainty around cadmium toxicity for wildlife leads to the conclusion that more species-specific ecotoxicological data is required for more realistic risk assessments. The predictions for starvation were subject to the limited quantitative information on biomass obtainable as food for vertebrates. It is concluded that the modelling approach employed in Eco-SpaCE, combining ecology with ecotoxicology, provides a viable option to explore the relative contribution of contamination to the overall stress in an ecosystem. This can help environmental managers to prioritize management options, and to reduce local risks.     

A globally applicable location-specific screening model for assessing the relative risk of pesticide leaching

A screening model of pesticide leaching loss is described which forms part of a multi-criteria risk-based indicator system called PRoMPT (Pesticide Risk Management and Profiling Tool). The leaching model evaluates pesticide fate in soil for any application rate and time of application (including multiple applications), for any land-based location in the world. It considers a generic evaluative environment with fixed dimensions and soil properties. The soil profile is conceptualised as a number of discrete layers. Equilibrium partitioning between adsorbed and dissolved chemical (based on the organic carbon-water partition coefficient [K(OC)]) is assumed in each time step, in each layer. Non-leaching losses are described using first order kinetics. Drainage is assumed to be uniform throughout the soil profile but varies temporally. The drainage rate, which can be augmented by evapotranspiration-adjusted irrigation, is derived from long-term mean monthly water balance model calculations performed for 30 arc-minute grid cells across the entire ice-free land surface of the earth. Although, such predictions are approximate, they do capture the seasonality and relative magnitude of drainage and allow the model to be applied anywhere, without the need for extensive data compilation. PRoMPT predictions are shown to be consistent with those made by more sophisticated models (PRZM, PELMO and PEARL) for the FOCUS groundwater scenarios.     

Processes releasing arsenic to groundwater in the Caldes de Malavella geothermal area, NE Spain

Arsenic concentrations exceeding the World Health Organization drinking water guideline (10 μg/L) have been measured in thermal and non-thermal groundwaters from the Caldes de Malavella geothermal area (La Selva graben, NE Spain). The CO₂-rich Na-HCO₃ thermal waters (up to 60 °C at the spring) have elevated arsenic concentrations ([As_T] from 50 to 80 μg/L). The non-thermal waters are of Ca-Na-HCO₃-Cl type and have [As_T] between <1 and 200 μg/L, defining a hot-spot distribution. The present-day contribution of As from CO₂-rich thermal waters to non-thermal aquifers is very limited, as shown by the concentration of geothermal tracers such as Li and B. Redox-controlling processes appear to govern the mobility of As in the non-thermal waters. Arsenate is clearly predominant in most oxidizing groundwaters (>85% of As(V) over total As), whereas reducing, high-As groundwater reaches up to 100% in arsenite. The reductive dissolution of Fe(III) oxyhydroxides and the coupled release and reduction of adsorbed As explain the elevated dissolved arsenite (up to 190 μg/L) and Fe (up to 14 mg/L) content in the more reducing non-thermal groundwater. Conversely, the high levels of nitrate (up to 136 mg/L) ensure an oxidizing environment in most non-thermal groundwaters ([As_T] between <1 and 60 μg/L). Under these conditions, Fe(III) oxyhydroxides are stable and As release to groundwater is not related to their dissolution. Instead, dissolved arsenate concentrations up to 60 μg/L are explained by a competition for sorption sites with other species, mainly bicarbonate and silicic acid, while arsenate desorption due to pH increase is not considered a major process.     

Analysis of Twitter messages using big data tools to evaluate and locate the activity in the city of Valencia (Spain)

This paper presents the big data architecture and work flow used to download georeferenced tweets, store them in a NoSQL database, analyse them using the Apache Spark framework, and visualize the results. The study covers a complete year (from December 10, 2016 to December 10, 2017) in the city of Valencia (Eastern Spain), which is considered to be the third most important in Spain, having a population of nearly 800,000 inhabitants and a size of 135 km². The concepts of a specific event map and a specific event map with positive or negative sentiment are developed to highlight the location of an event. This approach is undertaken by subtracting the heat map of a specific day from the mean daily heat map, which is obtained by taking into account the 365 days of the studied period.This paper demonstrates how the proposed analysis from tweets can be used to depict city events and discover their spatiotemporal characteristics. Finally, the combination of all daily specific events maps in a single map, leads to the conclusion that the city of Valencia city has appropriate urban infrastructures to support these events.     

Simulating pesticides in ditches to assess ecological risk (SPIDER): II. Benchmarking for the drainage model

SPIDER (simulating pesticides in ditches to assess ecological risk) is a locally distributed, capacitance-based model that accounts for pesticide entry into surface water bodies via spray drift, surface runoff, interlayer flow and drainage. SPIDER was developed for application to small agricultural catchments. Transport of pesticide from site of application to surface water via subsurface field drains is one of the major routes of entry to surface water. Several pesticide fate models describe transfer of pesticide via drainflow, notably MACRO which has been evaluated against field data in several studies. The capacity of SPIDER to simulate drainflow and pesticide concentration in drain water was evaluated against two datasets that had been used previously to evaluate MACRO independently of this study: a plot experiment at Cockle Park and a field experiment at Maidwell, both located in the UK. In both circumstances, SPIDER was able to reproduce drain hydrographs relatively well with no or limited calibration. At Cockle Park, simulated and observed drainflow over the season were 240 and 278 mm, respectively with a Nash and Sutcliffe model efficiency (NSME) coefficient of 0.32 whilst at Maidwell they were 259 and 296 mm, respectively with a NSME coefficient of 0.55. Prediction of maximum isoproturon concentration at Cockle Park by SPIDER and MACRO were 5.3 and 13.1 microg L(- 1) respectively compared to the 3.8 microg L(- 1) measured in the field, whilst pesticide load to drains over the season were 0.22 and 1.53 g, respectively, compared to an observed load of 0.35 g. Maximum sulfosulfuron concentration at Maidwell were 2.3, 3.9 and 5.4 microg L(- 1) for observed and as simulated by SPIDER and MACRO, respectively and pesticide loading to drains of the season was 0.77, 5.61, 4.77 g, respectively. Results from the sensitivity analysis showed that the sensitivity of SPIDER compared favourably to that of several other capacity models but was more sensitive than MACRO to variations in input parameters. SPIDER is currently being tested at the catchment scale.     

A model to assess the response of an arched roof of a lined tunnel

A model to analyze the response of an arched roof of a tunnel lining under a surface static loading is presented. It enhances a previous model by the authors, which is based on a discrete-continuous concept and is suitable for depths of burial at which ‘arching’ can develop. The current enhanced model takes into consideration the curvature of an arched roof of a lined tunnel. The proposed 2DOF system’s stiffness includes the influences of the soil side pressure as well as the arched geometry of the roof. For the case of zero curvature the analytical solution for the mid-roof deflection and average contact pressure that has been derived converges to the solution of a flat roof. The case of a relatively shallow buried structure has been calibrated and then verified against published experimental results.A case study shows that there is a certain opening angle of the roof at which the contact pressure has a maximum value. This angle coincides with the angle at which there is also a maximum value of the roof stiffness. However, it is also shown that approximately at this opening angle, the internal forces are minimal. It is therefore concluded that the average contact pressure is not necessarily the most important criterion for a design of an optimal shape of the roof. Furthermore, the angle that yields maximum contact pressure should be preferred for an optimal roof design. It is further shown that as the roof slenderness increases this optimal angle decreases.     

Evaluation of the ability of an artificial neural network model to assess the variation of groundwater quality in an area of blackfoot disease in Taiwan

The back-propagation (BP) artificial neural network (ANN) is applied to forecast the variation of the quality of groundwater in the blackfoot disease area in Taiwan. Three types of BP ANN models were established to evaluate their learning performance. Model A included five concentration parameters as input variables for seawater intrusion and three concentration parameters as input variables for arsenic pollutant, respectively, whereas models B and C used only one concentration parameter for each. Furthermore, model C used seasonal data from two seasons to train the ANN, whereas models A and C used only data from one season. The results indicate that model C outperforms models A and B. Model C can describe complex variation of groundwater quality and be used to perform reliable forecasting. Moreover, the number of hidden nodes does not significantly influence the performance of the ANN model in training or testing.     

A Bayesian network model to assess the public health risk associated with wet weather sewer overflows discharging into waterways

Overflows from sanitary sewers during wet weather, which occur when the hydraulic capacity of the sewer system is exceeded, are considered a potential threat to the ecological and public health of the waterways which receive these overflows. As a result, water retailers in Australia and internationally commit significant resources to manage and abate sewer overflows. However, whilst some studies have contributed to an increased understanding of the impacts and risks associated with these events, they are relatively few in number and there still is a general lack of knowledge in this area. A Bayesian network model to assess the public health risk associated with wet weather sewer overflows is presented in this paper. The Bayesian network approach is shown to provide significant benefits in the assessment of public health risks associated with wet weather sewer overflows. In particular, the ability for the model to account for the uncertainty inherent in sewer overflow events and subsequent impacts through the use of probabilities is a valuable function. In addition, the paper highlights the benefits of the probabilistic inference function of the Bayesian network in prioritising management options to minimise public health risks associated with sewer overflows.     

KNX/EIB系统在大型住宅小区地下室的应用

介绍某大型住宅小区,对园区路灯、景观设施,以及地下车库照明、送排风机、集水坑潜水泵采用KNX/EIB智能建筑控制系统;与人工手动控制系统进行比较,节能效果明显;案例工程KNX/EIB系统投资回收期约为4年。     

A habitat model for Parus major minor using a logistic regression model for the urban area of Osaka, Japan

We developed a habitat model for Great Tits, Parus major minor, in an urban area of Osaka, Japan. Although Great Tits play an important role in the urban food web, there are few in most of Osaka and downtown Tokyo, areas that have low vegetation cover. We derived a habitat model for Great Tits using a logistic regression model with GIS. A bird survey was conducted twice in 85 urban parks using the line census method in the breeding season, May–July 2000. A GIS base map was created from aerial photographs. The following variables were measured for each park from public records and GIS for predicting the habitat: park properties (age, distance to the nearest mountains, distance to the nearest forest of more than 10 ha), the number of other habitats occupied by the tits within 500 m and 1 km and area of tree cover (within it and surrounding parks). Number of nearby habitats and distance from the nearest mountains and forest of more than 10 ha are variables related to the regional populations of the tits. Area of tree cover was measured for five radii (50, 100, 150, 200, 250 m) from park centers, and a logistic regression model was calculated for each of these radii. Variables were selected by a stepwise method. The best fitting model of the five models was selected using Akaike’s Information Criteria. In the bird survey, the tit was recorded in 12 parks. The areas of parks occupied by the tit were 0.56–136.0 ha (mean: 26.0 ha±42.06 S.D., n=12). Variables selected in the best fitting model were area of tree cover in a radius of 250 m from park center and the number of other habitats within 1 km as positive factors. This model shows that area of tree cover within a certain range and number of nearby populations are the keys to the distribution of Great Tits. From this model obtained, 6.0 ha (31%), 4.0 ha (20%), 2.6 ha (13%) and 1.8 ha (9%) of tree area are needed to achieve probability of 0.5 in a radius of 250 m when numbers of other habitats within 1 km was 0–3, respectively. A realistic target figure is 10% of tree cover throughout urban areas to create an ecologically sustainable city.     

Geochemical prospection of cadmium in a high incidence area of prostate cancer, Sierra de Gata, Salamanca, Spain.

A high incidence of prostate cancer was observed in some areas of Salamanca province, Spain. After excluding the most common etiological factors as the cause, it is concluded that the only possible risk factor must be due to the presence of some environmental carcinogen. In view of the etiological relationship between Cd and the pathological state, a study was carried out on the geochemistry of this element in the area. Anomalous amounts of Cd were found in stream sediments. This anomaly does not correspond to human activity, but rather to high regional amounts of cadmium in the substrate. Thus, the contents of Cd in soils developed over substrates containing naturally-occurring anomalous amounts of cadmium and the concentration in underground waters should be considered as a risk factor in this area.     

Total and extractable contents of trace metals in agricultural soils of the Valderas area, Spain

The surface horizons of four agricultural field soils (Mollic ustifluvents, Alfic Xerochrepts, Typic Palexeralfs, Typic Haploxeralfs) were sampled to determine the total copper, cobalt, molybdenum, zinc, chromium, nickel, selenium, cadmium, lead, mercury, lithium and strontium, and were also fractionated by an extraction procedure to estimate the quantities of these trace metals in soluble form. The extractants used were the following: 1.0 N NH4 OAc for lithium and strontium, 0.05 M Na2-EDTA for cadmium, copper, nickel and zinc, 2.5% (w/v) acetic acid for lead, 2.5% (w/v) acetic acid and 2% (w/v) dithizone for cobalt, 2% (w/v) diethyldithiocarbamate solution for selenium, 0.1 NHCl for chromium, and 0.5 NHCl for mercury. The total content of these twelve elements in the four field soils sampled were lower than the levels quoted in the literature, although for different geochemical systems. The percentage of the total element content in soluble form was (except for selenium) generally very low, averaging between 5.5 and 8% for copper, 1.6 and 2.5% for cobalt, 8 and 10% for molybdenum, 1.8 and 2.2% for zinc, 14.2 and 17.7% for chromium, 5.5 and 6.4% for nickel, 30 and 55% for selenium, 8 and 14% for cadmium, 3 and 3.6% for lead, 8.3 and 11% for mercury, 5 and 7% for lithium, and 4.4 and 5.7% for strontium, regardless of the soil type.     

B-Spline函数在区域三维地下速度模型中的应用

基于B-Spline函数对大宗散乱数据的处理方法,将B-Spline函数应用到地震数值计算的物理模型中,优化了物理模型,使数值计算的稳定性及计算结果的准确性得以保证。