Understanding how pollution affects populations is critical for targeted environmental risk assessments and adequate protection of the environment. However, the vast majority of ecotoxicology studies still have a traditional focus of identifying effects on individual organisms and do not measure the effects at the population-level. Modelling tools that measure population effects of pollution are available and would add value to current ecotoxicology studies by aligning outcomes more closely to what needs to be protected. In this paper I outline three possible reasons why this knowledge gap still exists and consider how they could be adopted more broadly, including better considerations about what endpoints should be measured at the initial study design phase. The purpose of highlighting this knowledge gap is to assist in facilitating the integration of population-level endpoints into routine pollution monitoring programs and progress of ecologically relevant ecotoxicology research.

Disturbances in seagrass systems often lead to considerable loss of seagrass fauna. We examined the capacity for seagrass fauna, across multiple trophic levels, to recover from disturbances, using empirical and modelling techniques. Model outputs, using Ecosim with Ecopath (EwE), were consistent with the results of field investigations, highlighting the models robustness. Modelled outcomes suggest second and third order consumers are likely to be negatively effected by disturbances in the seagrass canopy. Particularly piscivores, which once disturbed, appear unlikely to recover following severe declines in primary productivity. EwE also revealed the complex interaction between the duration and intensity of disturbances on seagrass fauna, which may differentially affect higher order consumers. Further, modelling predicted a variable capacity of higher order consumers to recover from successive disturbances, suggesting taxa with comparatively fast reproductive cycles and short generation terms would be more resilient than taxa with comparatively long generation terms and slow reproductive cycles.

Susceptibility to pollution can be related to the flushing capacity of aquatic systems. Transport time scales constitute a useful tool for representing the water exchange and transport processes. A new transport time scale, recovery time, and a methodology to estimate it by means of numerical models is hereby developed. Recovery time, calculated in Gijon, Santander and Tarragona harbours, is significantly related to physical, chemical and biological water quality indicators. Susceptibility, assessed through recovery time values, provides spatial patterns of expected flushing capacity, being sensitive to physical and hydrodynamic characteristics. The developed method is appropriate to estimate recovery time and assess susceptibility against pollution in littoral waters having great potential to be applied to different disciplines. Recovery time could be used in littoral waters as a surrogate of water quality indicators, to establish efficient monitoring programs, to define and characterize modified water bodies or to improve the design of marine infrastructures.

In order to assess the status of a North Atlantic Ocean Ecoregion (Mondego system, Portugal) after the implementation of a management programme, a study on PO4-P sorption was carried out. Considering that sorption velocity markedly determines the systems promptness to phosphorus external loading, the kinetics of the sorption of PO4-P onto estuarine sediments and the upstream agricultural soils was studied. The pseudo-second order kinetic equation gave an appropriate description of PO4-P sorption onto these soils and sediments, allowing for a quantitative comparison. For soils, the kinetic constants (k2⁎, μg−1gh−1) ranged between 0.007 and 0.017μg−1gh−1 while, in the case of sediments these ranged between 0.008 and 0.012μg−1gh−1. Results showed that the reduction of water residence time after the management action was relevant for the system status, affecting its reaction capacity to phosphorus loading.

Investigations on setting benthic macroinvertebrates reference conditions in natural waters have increased recently. Under the European Water Framework Directive, importance is given to research in morphological heavily-modified water bodies (HMWBs), which are very common in countries with high human pressure. However, research has not been undertaken on setting the maximum ecological potential (MEP), as a reference in HMWB. The objective of the present investigation is to set the MEP of two metrics (diversity and richness), used in assessing the ecological status in different benthic indices. The Oiartzun estuary (Basque Country) is used as a case study, which changed morphologically in the 19th Century, following harbour construction. Data obtained from 1874 and the present were used to model changes in currents, water residence time, salinity, volume, and intertidal area. Benthic macroinvertebrate data, from 1995 to 2011, were used to predict 19th Century and present MEP. Changes in the estuary were described: loss of all of the intertidal areas; doubling of the volume; residence time, changing from 2 to 95days; current velocity reduced by 50%; salinity increase. All these factors have led to changes in the benthic communities and the structural variables. Predicted richness and diversity, for 1874, were lower (48–76%) than those at present. Taking into account the differences between natural and modified waters, it is proposed to utilize 75% of the natural reference conditions, as the MEP values for Basque HMWB.

This study estimates air pollution at urban background level for Quito, Ecuador, using the Urban Background Model (UBM) developed at Aarhus University, Denmark. Hourly concentrations of CO, NO₂, NOₓ, O₃, PM₂.₅ and SO₂ were calculated for the year 2009. UBM performance is evaluated at six monitoring locations. The air pollution emission inventory was scaled, using calibration factors, until modeled concentrations were in line with observations. Predicted values were graphically and statistically evaluated by comparison to measurements. The statistical assessment is conducted for: Fraction of predictions within a factor of two of the observations (FAC2), Fractional mean bias (FB), Normalized mean-square error (NMSE) and Normalized absolute difference (NAD). Results show that the UBM model successfully predicts concentrations of CO, NO₂, NOₓ, O₃ and PM₂.₅ while the predicted SO₂ concentrations are unsatisfactory. PM₂.₅ modeling meets the criteria of acceptance, but their results depend largely on the regional levels, so the quality of this information is extremely relevant. The UBM model was applied for the years 2008 and 2010 using meteorological data retrieved from the modeling sites with emissions and calibration factors derived for the year 2009, showing a performance similar to that of 2009. The findings confirm the applicability of UBM to predict air pollution at the urban background level in Quito. Satisfactory results are obtained by applying meteorological data derived from any of the available monitoring stations. The unsatisfactory results for SO₂ suggest that emission data should be reviewed and that this cannot be obtained simply by scaling.

Biochar amendments could enhance retention of nutrients such as ammonium (NH4+), nitrate (NO3-), and phosphate (PO43-) in soils. However, the situation for sulphate (SO42-), which is an indispensable nutrient element for crop growth, is unclear. In this paper, the effects of biochar derived from rape (Brassica campesstris L.) straw at 600°C on the sorption and leaching of SO42- in light sierozem (Calcids) was studied in columns, where biochar amendment rate, column soil height, solution pH value and initial sulphate concentration were selected as factors. It is shown that the transport of sulphate was a significant non-equilibrium process and the sorption and leaching curves (SLCs) of sulphate were asymmetrical. The breakthrough time would be increased by increasing biochar amendment and soil column height, and by decreasing solution pH value and initial sulphate concentration. The SLCs of bromide trace were fitted to determine dispersion coefficient (D) using equilibrium convection dispersion equation (CDEeq). The non-equilibrium (two-site) model (CDEnon-eq) with the results from CDEeq was used to simulate the transport processes of sulphate in the soil column, with good fitness, using software CXTFIT 2.1 fitting. The results could supply an implication for biochar application in loess areas.

The essential issues solved by geoenvironmental engineers relate to the assurance of uncontaminated regions of the subsurface just as the remediation of locales of the subsurface that have been sullied by releasing waste materials, spilling over the ground and underground stockpiling tanks and penetration of pesticides. In city areas, garbage and waste materials are generally dumped into landfills. A landfill site, which is otherwise called a trash dump, is used for the disposal of waste materials by burial. A safe landfill is a deliberately built sorrow in the ground into which wastes are put. The principal objective is to stay away from any water driven association between the wastes and the surrounding environment especially groundwater. This paper discusses landfill, in terms of its construction, stability and failure. The analysis and modelling of the landfill failure occurred in different countries like Poland, Turkey, Israel, the Philippines, China and Sri Lanka which are discussed.

Les eaux superficielles et souterraines doivent recouvrer une bonne qualité chimique et biologique avant 2015, d'après la Directive Cadre Européenne. Les Bonnes Pratiques Agricoles (BPA) établissent un compromis entre les risques de pollution et de perte de revenu. Le résultat minimal escompté est de respecter la norme de potabilité de 50 mgNO3.L-1 dans les eaux de captage et d'éviter les transferts de pollution de l'hydrosphère vers l'atmosphère. Cependant leur mise en oeuvre ne garantit pas d'atteindre ces objectifs ; cela nécessite des moyens de quantifier l'impact des pratiques agricoles effectives sur la pollution nitrique. Nous avons testé différentes méthodes de quantification, en nous appuyant sur les données issues d'une expérimentation partenariale de prévention de la pollution, menée sur le site de Bruyères (02). La question finalisée est "quel est l'impact des BPA, appliquées de façon systématique, à l'échelle d'un bassin"? La question de recherche est "peut-on modéliser la pollution nitrique, en situation agricole, à l'échelle du bassin hydrologique"? Le site d'étude est un plateau de 187 ha qui alimente une nappe d'eau souterraine, sise dans le Lutétien. Cette nappe alimente 5 sources principales qui connaissent une pollution croissante depuis 1970. Les 21 parcelles cultivées du plateau ont fait l'objet d'une mise en oeuvre systématique des BPA, par les 3 agriculteurs, depuis 1990. Les pratiques agricoles et l'hydrogéologie du site ont été caractérisées. Les débits des sources répondent aux pluies efficaces dans un délai d'une semaine. Le temps moyen de séjour de la molécule de Tritium dans l'aquifère est de 25 ans, à cause de l'épaisseur de la zone non saturée. Compte tenu de ce délai, un niveau intermédiaire d'évaluation est nécessaire : les pertes sous la zone racinaire. Les méthodes de quantification diffèrent selon leur degré de dépendance aux données expérimentales : i) le modèle de calcul LIXIM, associé avec toutes les données observées; ii) un modèle stochastique de réponse des cultures à la dose d'azote, initialisé annuellement; iii) le modèle fonctionnel dynamique STICS, qui peut simuler les pertes du système sol- plante- atmosphère de façon continue pendant plusieurs années. Les prédictions des variables d'intérêt économique et environnemental sont confrontées, aux données observées, aux échelles de la station et du bassin. Les impacts environnementaux et économiques, de différents scénarios de prévention de la pollution, sont simulés. Les reliquats d'azote minéral à la récolte et en entrée d'hiver sont proches et stables dans le temps avec respectivement 41 et 57 kgN.ha-1. L'intégration des flux calculés avec LIXIM, à l'échelle de la rotation culturale, conduit à lisser le facteur culture et à faire du type de sol le principal déterminant de la concentration. La teneur en nitrate moyenne pondérée, de l'eau de percolation, est de 46 mgNO3.L-1 pour la zone cultivée et de 37 mgNO3.L-1 pour l'ensemble du bassin. Ce bon résultat est confirmé qualitativement par la baisse constatée des teneurs de plusieurs captages depuis l'an 2000. Le temps de réponse de l'aquifère serait égal à la moitié de son temps de renouvellement. L'abattement de la teneur en nitrate de l'eau de percolation permis par les BPA, relativement à un scénario conventionnel, est compris entre 27 et 39 %, suivant la méthode de simulation. Le coût des BPA est de 0.07 | Surface and groundwaters must regain good chemical and biological quality before 2015 according to European Directives. Good Agricultural Practices (GAPs) establish a compromise between the risks of pollution and the loss of revenue. The minimum result expected is conformity with the drinking water standard of 50 mgNO3.L-1 in the collected water and the avoidance of transfer of pollution from the hydrosphere into the atmosphere. However their implementation does not guarantee that these objectives will be reached ; that requires a means of quantifying the impact of effective agricultural practices on nitrate pollution. We have tested different methods of quantification by using data from a collaborative experiment on pollution prevention, carried out on the site of Bruyères (02). The question targeted was « what is the impact of GAP, applied regularly, on the scale of a catchment area ? » The research question was « can nitrate pollution be modelled, in a farming situation, on the scale of a catchment area ? » The study site is a plateau of 187 ha which supplies a groundwater aquifer located in the Lutetian geological layer. This aquifer feeds five main springs which have suffered increasing pollution since 1970. The 21 cultivated fields on the plateau were subjected to regular implementation of GAPs by the three farmers since 1990. The farming practices and the hydrogeology of the site were characterised. The flow rates of the springs respond to effective rainfall after a delay of a week. The mean residence time of the tritium molecule in the aquifer is 25 years, because of the thickness of the unsaturated zone. In view of this delay, an intermediate level of evaluation is necessary : the losses under the root zone. The methods of quantification differ according to their degree of dependence on the experimental data : i) the LIXIM mathematical model, associated with all the observed data ; ii) a stochastic model of crop response to the nitrogen rate, initialised each year, iii) the functional dynamic model STICS, which can simulate the losses of the soil/plant/atmosphere system continuously over several years. The predictions of the variables of economic and environmental interest are compared with the observed data on the scale of the station and of the basin. The environmental and economic impacts for different scenarios of pollution prevention are simulated. The mineral nitrogen residues at harvest and at the beginning of winter are similar and stable over time at 41 et 57 kgN.ha-1 respectively. The averaging of the losses, calculated with LIXIM, over the crop rotation, smooths out the crop factor and makes the soil type the principal determinant of the concentration. The mean weighted nitrate concentration in the percolating water is 46 mgNO3.L-1 for the cultivated zone and 37 mgNO3.L-1 for the whole basin. This good result is confirmed qualitatively by the fall observed in the contents at several collection points since the year 2000. The response time of the aquifer would be equal to half of its renewal time. The reduction in the nitrate content of the percolation water permitted by GAPs, compared with a conventional scenario, is between 27 and 39%, depending on the simulation method. The cost of the GAPs is 0.07 €.m-3 of drinked water, making prevention competitive with water treatment at the Bruyères site. Dynamic modelling with STICS appears to be effective in the agricultural situation, but its reliability depends on the availability and relevance of the databases used to calibrate it. It can take account of a large number of technical inputs and their long-term interactions. Coupling STICS with a geographical information system (GIS) enables the spatial variability of the physical and cultural features of the environment to be integrated. However it is not possible to guarantee the reliability of the predictions for both any time and any place. Access to the precise value of parameters like the crop’s maximum rooting depth or the stock of organic nitrogen is simply not feasible. According to the STICS model, the nitrogen losses simulated in gaseous form are equal to those in solution. This result needs to be verified. Bearing in mind these limitations, modelling based on experimentation can become a management tool for nitrogen in cropping systems on a regional scale. The problem of limiting nitrate leaching is shifted towards the conception of sustainable cropping systems.