Amazon River dissolved load: temporal dynamics and annual budget from the Andes to the ocean

The aim of the present study is to estimate the export fluxes of major dissolved species at the scale of the Amazon basin, to identify the main parameters controlling their spatial distribution and to identify the role of discharge variability in the variability of the total dissolved solid (TDS) flux through the hydrological cycle. Data are compiled from the monthly hydrochemistry and daily discharge database of the “Programa Climatologico y Hidrologico de la Cuenca Amazonica de Bolivia” (PHICAB) and the HYBAM observatories from 34 stations distributed over the Amazon basin (for the 1983–1992 and 2000–2012 periods, respectively). This paper consists of a first global observation of the fluxes and temporal dynamics of each geomorphological domain of the Amazon basin. Based on mean interannual monthly flux calculations, we estimated that the Amazon basin delivered approximately 272?×?10⁶ t year^?1 (263–278) of TDS during the 2003–2012 period, which represents approximately 7 % of the continental inputs to the oceans. This flux is mainly made up by HCO₃, Ca and SiO₂, reflecting the preferential contributions of carbonate and silicate chemical weathering to the Amazon River Basin. The main tributaries contributing to the TDS flux are the Marañon and Ucayali Rivers (approximately 50 % of the TDS production over 14 % of the Amazon basin area) due to the weathering of carbonates and evaporites drained by their Andean tributaries. An Andes–sedimentary area–shield TDS flux (and specific flux) gradient is observed throughout the basin and is first explained by the TDS concentration contrast between these domains, rather than variability in runoff. This observation highlights that, under tropical context, the weathering flux repartition is primarily controlled by the geomorphological/geological setting and confirms that sedimentary areas are currently active in terms of the production of dissolved load. The log relationships of concentration vs discharge have been characterized over all the studied stations and for all elements. The analysis of the slope of the relationship within the selected contexts reveals that the variability in TDS flux is mainly controlled by the discharge variability throughout the hydrological year. At the outlet of the basin, a clockwise hysteresis is observed for TDS concentration and is mainly controlled by Ca and HCO₃ hysteresis, highlighting the need for a sampling strategy with a monthly frequency to accurately determine the TDS fluxes of the basin. The evaporite dissolution flux tends to be constant, whereas dissolved load fluxes released from other sources (silicate weathering, carbonate weathering, biological and/or atmospheric inputs) are mainly driven by variability in discharge. These results suggest that past and further climate variability had or will have a direct impact on the variability of dissolved fluxes in the Amazon. Further studies need to be performed to better understand the processes controlling the dynamics of weathering fluxes and their applicability to present-day concentration–discharge relationships at longer timescales.     

Assessing multiple novel tracers to improve the understanding of the contribution of agricultural farm waste to diffuse water pollution

A study was undertaken on drained and undrained 1 ha grassland lysimeters to assess the effectiveness of multiple novel tracing techniques in understanding how agricultural slurry waste moves from land to water. Artificial fluorescent particles designed to mimic the size and density of organic slurry particles were found to move off the grassland via inter-flow (surface + lateral through-flow) and drain-flow. Where both pathways were present the drains carried the greater number of particles. The results of the natural fluorescence and δ13C of water samples were inconclusive. Natural fluorescence was higher from slurry-amended lysimeters than from zero-slurry lysimeters, however, a fluorescence decay experiment suggested that no slurry signal should be present given the time between slurry application and the onset of drainage. The δ13C values of >0.7 microm and <0.7 microm material in drainage were varied and unrelated to discharge. The mean value of >0.7 microm δ13C in water from the drain-flow pathways was higher from the lysimeter which had received naturally enriched maize slurry compared to the lysimeter which received grass slurry indicating a contribution of slurry-derived material. Values of <0.7 microm δ13C from the same pathway, however, produced counter intuitive trends and may indicate that different fractions of the slurry have different δ13C values.     

Ecotoxicity and genotoxicity assessment of losartan after UV/H2O2 and UVC/photolysis treatments

Environmental Science and Pollution Research - Losartan potassium (LOS) is one of the most antihypertensives used in the world, and its presence in environmental matrices can cause impacts to...     

Well-being for all? The social distribution of benefits gained from woodlands and forests in Britain

Well-being is a positive physical, mental and social state and has increasingly become an area of interest to researchers and policy-makers internationally. This paper presents results from research that analyses the well-being benefits gained by different sections of society through viewing, engaging with, and accessing woodlands and forests in Britain. We draw on 31 studies undertaken since 2001 and present a meta-analysis of quantitative data and a meta-synthesis of qualitative data to explore the range of benefits and associated activities in woodlands, and their social distribution. We also present a state-of-the-art typology of well-being benefits for woodlands in Britain. The findings illustrate the wide range of well-being benefits gained by different social groups through various forms of engagement with and activities undertaken in woodlands. We illustrate the wide range of meanings and values attached to trees and woodlands across different social groups. The evidence also illustrates how carefully designed and targeted interventions can be particularly effective in enabling and encouraging people to visit woodland sites, to participate or get involved in new activities and, therefore, to realise a range of well-being benefits.     

Using secondary data to analyse socio-economic impacts of water management actions

This paper provides an analysis of the socio-economic impacts of river restoration schemes, and is novel in considering how a wide range of socio-economic variables can be used to understand impacts on the entire resident population within an area. A control-impacted approach was applied to explore differences in socio-economic characteristics of areas within which a restoration scheme had been carried out compared to areas without such a scheme. The results show that significant differences exist between control and impacted areas for a range of socio-economic variables. However, due to constraints in the methods and the data available, there are currently limitations in the extent to which socio-economic impacts of river restoration schemes can be fully explored. Additional datasets that become available in the future may increase the ability to detect associations between improvements in the water environment and socio-economic benefits. However, whilst the secondary data used in this paper are potentially powerful, they should be used alongside other techniques for assessing the impacts of decisions as part of future frameworks to deliver sustainable water management.     

Concentrations, sources and temporal trends in atmospheric polycyclic aromatic hydrocarbons in a major conurbation

Concentrations of atmospheric PAH were separately determined in total suspended particulate matter and associated vapour phase in ambient air in Birmingham, UK. Samples of 24 h duration were taken simultaneously at two locations (the Bristol Road Observatory Site, BROS, and the Elms Road Observatory Site, EROS) on 44 separate occasions every one to two weeks between October 1999 and January 2001. BROS was 10 m from the busy Bristol Road, 800 m from EROS that was located within the "green space" of the University of Birmingham campus. With the exception of acenaphthene, average concentrations of all measured PAH at BROS exceed those at EROS, with a paired t-test revealing these roadside increments to be significant (p < 0.05) for 9 out of the 16 target PAH, demonstrating the importance of traffic emissions of PAH. Although the declines were not statistically significant (p > 0.05) except for phenanthrene and fluoranthene, concentrations of individual PAH at EROS between July and December inclusive in 1999 and 2000 fell by between 16 and 54% compared with those during the same months in 1997. Multiple linear regression of PAH concentrations against meteorological variables confirmed the influence of the Bristol Road on BROS but not EROS. Cluster analysis of PAH contamination in individual samples showed there to be two statistically distinct groups of samples. One group contained 15 samples, all of which displayed elevated concentrations. Examination of air mass back trajectory data, revealed that these PAH pollution episodes originate due to the combined effects of meteorology and local traffic emissions, rather than as a result of long-range transport. Eighteen 12 h samples were also taken at EROS over the period of the November Bonfire Night festivals of 1999 and 2000. These revealed significantly elevated PAH concentrations on the nights when ignition of bonfires and fireworks would be anticipated to peak. These results are relevant to assessments of the impact of similar "festivals of fire" elsewhere. In particular, retene (7-isopropyl-1-methylphenanthrene) concentrations were especially elevated, indicating it has possible utility as an indicator of wood combustion emissions.     

Northern conditions influencing the selection of countermeasures after radioactive fallout in Finland

The paper summarizes an evaluation of practicability of rural countermeasures after radioactive fallout in northern conditions carried out by a Finnish group of experts in the FARMING Network project. Snow and soil frost limit the selection of crops, and the short growing season allows mostly one harvest yearly. Cold climate restricts fruit production to apples and berries. Due to the long indoor feeding period, conserved and stored clean feed is available almost all year round. The use of fertilisers and lime on poor and acidic soils leads to high potassium and calcium intake of cows increasing the incidence of milk fever. The surface soil layer is thin and ploughing deeper than 20 cm is problematic due to stony and compacted soils. It also increases soil acidity and decreases fertility. Cultivation of peatlands limits the selection of plants and increases long-term radiocaesium contamination of crops. Frost and snow delay ploughing and spreading of waste milk on arable land, but removal of snow is a decontamination option. Long distances and high transport costs complicate carrying out the countermeasures. The Finnish stakeholder group considered it vital to be prepared for implementation of practicable measures for the safety of food.     

Can Large-Scale Climatic Models Be Linked with Multiscale Ecological Studies?*

On a global scale climatic changes driven by human activities are typically projected to increase from 1° C to 5° C per 100 years a rate of change that is an order of magnitude greater than that typically experienced naturally. Such a potentially dramatic change in climate could easily cause dramatic biological responses including extinction. Species show a wide range of responses to climate and consequently the response of different species of plants and animals to climatic change will be quite variable. This implies a likelihood for a disassembling of natural communities and for transient, nonequivalent restructuring of habitats as climatic change unfolds. Validated models that help forecast these events are needed to aid scientists in better understanding the ecological ramifications of global climatic change. Also, and perhaps more important for conservation biology, such validated models can help provide probabilities for the occurrence of these events, which will allow policy makers to make better, informed decisions. Typically, the study plots of most ecological field work are telecommunications, while the smallest resolved scales in global climatic models are about 500 × 500 km. Computer limitations preclude significant reduction in scales of climatic models. Consequently, more multi-species ecological studies are needed over broad geographic and long temporal scales. We provide an example of large-scale ecological response studies, namely the case of wintering North American birds. We also provide an example of attempts to translate results of large-scale climatic models (at a 500 × 500 km scale) to a mesoscale (50 × 50 km). Participation of climatologists with ecologists at early stages in research planning can help bridge the scale mismatch between climatic and ecological measurement, and provide more reliable estimates of community responses to century-long, time-evolving patterns of climatic change. We are convinced that many more such interdisciplinary research attempts are urgently needed if the scientific community is to produce information useful to the development of conservation strategies. Such strategies might help to mitigate potential negative consequences of global climatic changes before they manifest themselves irreversibly in nature.