AquaTerra - an Integrated Project of the 6th EU RTD Framework Programme
AquaTerra is an integrated project of the 6th EU RTD Framework Programme that aims to provide the scientific basis for an improved river basin management through a better understanding of the river-sediment-soil-groundwater system as a whole, by integrating both natural and socio-economics aspects at different temporal and spatial scales.
With the onset of mining, man started to distribute elements on the earth's surface which were until then to a large extent hidden in the earth's crust. During many centuries of mining operations - sometimes more that 1000 years - river sediments and consequently floodplain soils became enriched with heavy metals. With the increase of the population after the medieval era the increased burning of biomass and coal caused the deposition of soot, chars and associated organic compounds such as the carcinogenic polycyclic aromatic hydrocarbons (PAHs) on soils. Sites with coal based industries (ore smelters, glass production, charcoal piles) produced severe local soil pollution. After the onset of the industrial revolution emission of pyrogenic compounds into the atmosphere and soils increased by a factor of approx. 100 mostly connected due to increased energy demand covered by fossil fuel (coal and oil). In the 20iest century manufactured chemicals for many purposes were released into the environment in large volumes. The most prominent group are chlorinated compounds used as pesticides (DDT, lindane, PCP), flame retardants (PCBs later PBDE), solvents (TCE, PCE, etc.). These manmade compounds are inherently stable and therefore they occur now at a global scale and throughout the food web. Meanwhile, there is no doubt that these manmade compounds produced a chemical footprint on the whole planet, which is an often overseen but important aspect of global change.
Through comprehensive sampling and monitoring campaigns in diverse European river basins, using newly developed leading-edge approaches and methods, AquaTerra could show that many manmade chemical compounds can be found today ubiquitously, in all compartments, in air, in soil and sediments, in surface waters as well in groundwater.
The environmental impact of these compounds develops a dynamic behaviour and numerous processes govern the pathway of pollutants in the environment. They range from complex input functions into soils and surface water to migration processes in soil, groundwater, surface water and sediments to redistribution processes from soil and water into the atmosphere.
Following this "chemocycle" of pollutants, AquaTerra made huge collective efforts to identify and parameterize the biological, chemical and physical processes relevant for the prediction of the long-term fate and impact of man-made pollutants in the environment.
Despite environmental regulations such as the Stockholm Convention on persistent organic pollutants (regulating the so-called “dirty dozen”), new compounds are continuously designed, produced and will eventually enter the environment.
The novel measurement and analyse techniques developed in AquaTerra allow to detect more and more compounds (incl. newly emitted compounds) today.
Not only do scientists need to understand how systems might function particularly with respect to transfer of pollutants, but also do societies need to react to environmental loads of pollutants, their transfer and accumulation on an international basis. The latter becomes increasingly important if large scales are considered.
AquaTerra’s work was based on strong stakeholder involvement, regarding knowledge production as a social process in order to present scientific results in a manner that makes it of use and interest to as wide a range of potential end users as possible.
Top soils serve as filter for deposited pollutants, which protects groundwater bodies effectively against diffuse pollution in many areas in Europe. Resilience works today but accumulation in soils and sediments results in increasing concentration of many compounds. Concentrations of many compounds are still relatively low often at trace levels (except at hot spots e.g. contaminated sites, which act as secondary sources) but there is a clear trend of not just of increasing concentrations but also in the number of compounds appearing. Whether these cocktails cause any toxicological effects on man or biota is unclear. Do low concentrations of xenobiotic compounds matter at all and how fast are organic compounds degraded or diluted in the environment? How much can the system take before a "real" damage occurs? Diffuse pollution is not easily reversible and the question arises how permanent a ubiquitous chemical footprint is?
To answer these vital questions, AquaTerra made a great step forward in the development of process-based numerical models that are capable of making predictions of likely trends and environmental changes to be expected in near or far distant future. These models can be used e.g. to generate hydrologic scenarios based on climate models and to simulate pollutant distribution and turnover rates from decades to millennia.