Further description:-  Regulation 

Glossary Entry
Principle, rule, or law designed to control or govern conduct. 
Level 1: Diffuse Pollution:

Further information:

 

Sustainable land use requires active or passive control of large-scale diffuse matter fluxes into, within and out of agro-ecosystems. This calls for effective methods and tools to monitor of these fluxes, to assess the effects caused by low-rate large-scale accumulation of pollutants, and to develop strategies and techniques to prevent and decrease this type of pollution. In addition there is the challenging task to treat already affected soils and waters. Successful large-scale and long-term management of material fluxes in agroecosystems and of land affected by diffuse low to medium-level pollution cannot be achieved by the same strategies and methods developed for the detection, classification and treatment of hot spot contamination such as hazardous waste sites. It requires the development of suitable tools to:

 

-         survey and monitor the state and development of soil and water

     pollution

-    understand the environmental behaviour and fate of the pollutants

-    assess and evaluate the ecological, economical and toxicological risks

-         develop problem-adequate abatement, management and remediation

     strategies.

 

1          Survey and monitoring of the state and development of soil and water pollution

Any policy, management strategy or other measure to control diffuse soil and water pollution can only be successful in the long run, if the state of the pollution is monitored and trends of future development are detected at an early stage. This information is necessary to 1) target measures effectively and 2) control the success of the interventions.

 

1.1      Monitoring the state and spatial distribution of diffuse pollution

Many European states, e.g. Germany, Austria, the Netherlands and Switzerland, have established soil and groundwater monitoring programmes. These programmes vary considerably with respect to their strategy, the monitored parameters, the employed sampling and analytical methods, the design and density of the sampling grid and the intervals between surveys. In general, only a few trace metals and macro-nutrients are monitored, and usually only total concentrations and no bioavailable or mobile fractions are determined.

These programmes give a good overview of the overall situation with respect to the pollutants under survey, but the spatial sampling densities of the networks are not sufficient to allow mapping. Maps are, however, needed in order to adequately account for the distribution of contamination in the management of the land. The required spatial resolution depends on the intended use of that information. In mapping soil and groundwater pollution the problem is to extrapolate or predict the pollution in the areas between the points at which it has actually been measured. The accuracy of the prediction depends on the design of the sampling grid, in particular the density of the sampled points, the spatial structure of the variability and the availability of additional information with indicator values for the state of pollution. Land use data are particularly valuable for this purpose in groundwater as well as soil pollution surveying. In addition, the following proxy methods have been proposed to improve soil pollution mapping: geomagnetics, biosensors, remote sensing and historical information on land use (e.g. application of copper sulfate in vineyards, reclamation of former industrial areas, waste disposal sites). Geostatistics provides methods to make optimum use of the available data.

 

1.2      Mass flux balances: a tool to detect and to control the accumulation of pollution

The knowledge of the material fluxes is very important in assessing the development of a pollution situation and its potential impacts. Mass balances schemes and material flux models determine, analyse and predict pollutant accumulation in soil. Material fluxes in agricultural soils vary considerably in space and time depending on factors such as types of farms, types of cultivation practices, number of animals per unit area, production of animal manure per unit area of farm. Keller (2000) found that net accumulation of cadmium in agricultural soils varied between 0.6 and  17.8 g ha-1 a-1 and zinc accumulation between 17.9 and 3360 g ha-1 a-1 in a rural region of Switzerland.

Another question to be solved is the deposition (by erosion and/or runoff) and the re-use of excavated soil like materials/sediments. In addition, the influence of background geogenic loads and the impact of current and historical land uses on soil quality are not being systematically investigated and interpreted except at dumping sites.

 

2          Environmental behaviour and fate of the pollutants

Attempts to control the nitrate problem in most cases did not regard chemical and biological processes in aquifers such as interactions between solution phase and rock matrix and denitrification.

The elimination of undesired macro-nutrients in aquifers such as nitrate depends on the availability of biochemical reaction partners such as organic carbon or iron sulfides, their spatial distribution in relation to flows, and the rates of fluxes. Mostly, the properties of the aquifer due to attenuation are unknown and the processes running in the aquifer can mathematically only be expressed inadequately.

Figure 1 schematically shows a nitrate plume approaching an extraction well. Part of the plume is remediated by a permeable layer that contains electron donors (reactive material). This layer is displayed in the drilling core. Nitrate is eliminated in this layer by denitrification, which occurs because of the presence of the reactive material.

The aquifer is handled as a black box. The knowledge about the mechanisms of reaction that lead to a decrease of unwanted concentrations, their spatial subterranean distribution and life span that lead to a decrease of unwanted concentrations are vital for the planning and operation of water extraction plants. If it is diagnosed that the elimination capacity of the aquifer is limited, these findings have influence on decisions on which treatment techniques will have to be employed in the waterworks and on which plots of land measures have to be taken in order to secure future water supply.

The preparation of maps of “vulnerability of aquifers" (e.g. in Germany developed by the geological surveys) can show the potential of natural attenuation to eliminate specific substances. This geopotential, e.g. for nitrate elimination, is rarely considered during the planning of the land use up to now.

The processes of natural attenuation of macro-nutrients in aquifers, their spatial distribution and their lifespan are still unknown to a large extent. There is a great need for research in this field to expand the knowledge required to protect groundwater and the capacity of aquifers to eliminate or attenuate pollutants. Such knowledge is an essential basis for a sustainable management of drinking water resources.

 

Figure 1: nitrate input in an aquifer and transport towards an extraction well, while part of the plume is eliminated by reactive materials shown in the drilling core at left.

 

 

3          Assessment and evaluation of effects of diffuse soil and water pollution

The evaluation of soil and water pollution can be based on:

·        Transfer into the food chain and toxicity risks for humans, animals and plants

·        Transfer and potential effects in other compartments

·        Degradation of soil quality, e.g. for plant production

·        Degradation of groundwater quality and elimination capacity of the aquifer

·        Disturbance of ecosystem properties, e.g. population community structures, and ecosystem functions such as organic matter decomposition

The following example illustrates how diffuse pollution by macro-nutrients can not only disturb ecological processes, but also damage the physical properties of the subsurface. Aquifers are oligotrophic ecological systems. There is considerable concern that similar effects of the eutrophication will occur as in the past in oligotrophic surface waters such as lakes. Increased bacterial growth can lead to the clogging of pores and thus alter hydraulic conductivities. Perceptions about the effects on the groundwater ecological system are not available up to now.

Present concepts of hazard and risk assessment are primarily focussing on hot spot pollution. Risk assessment of diffuse pollution effects is usually restricted to effects on human health due to pollutant transfer through the food chain including drinking water and to direct uptake of contaminated soil particles, which is particularly relevant for small children).

Further gaps:

·        There is little knowledge about combined effects of different pollutants, indirect effects of pollutants and the influence of other factors on the impact of pollutants,

·        Not all relevant processes resulting in pollutant transfer between different environmental compartments appear to be sufficiently understood and taken into account (e.g. re-entry of trapped pollutants into natural cycles by excavation of sediments or redistribution and deposition of polluted sediments on land after flood events),

·        There is a lack of uniform approaches as well as and cheap and reliable procedures to assess and evaluate ecotoxicological effects,

·        Present approaches assume constant conditions over time,

·        Present approaches do not or insufficiently consider spatial hetergeneity

·        Toxicity (different methods for sample collection), carcinogenicity, bio-availability of pollutants have so far only marginally been considered

·        Measurement of medium-term bioavailable fraction of total pollutants which can be assessed (EDTA+ Ammonium acetate buffered extractable methods)

·        Hazard assessment of new pollutant or cluster of pollutants entering in the terrestrial ecosystem (e.g. additives such as the distribution of metals having catalysing effects along motorways, anti- knocking)

Various indicators are proposed to monitor polluted soils. Some indicators have been for assessing critical or threshold concentrations. These indicators are not sufficient to indicate the impact of pollutants.

Indicators, which reflect the bio-availability of pollutants are more suitable for assessment of toxicity. Bio-sensors are promising tools to assess the toxicity of pollutant cocktails. Total concentrations of pollutants are of limited value as indicators of actual toxicity.

 

4          Measures to reduce, remediate and control diffuse soil and water pollution

4.1      Measures to reduce, remediate control diffuse soil pollution

In order to develop an adequate management strategy to manage large-scale diffuse soil pollution, goals have to be set based not only on the pollution and its expected future development but also on the specific functions of the affected soils and their sensitivity. The functions to be considered include the production of food, feed, fruits etc. as well as life supporting ecosystem services of soils. In this context, the filter, buffer and transformation capacity of soils have to be mentioned as essential for groundwater recharge.

 

4.2      Measures to reduce, remediate and control diffuse water pollution

During the last three decades, considerable attempts have been made to develop suitable ways to decrease e.g. diffuse nitrogen and phosphorus loads in waters.

Regulations relating to water protection employ different concepts: protection zones which were issued by water administrations, creation of co-operations between farmers, agricultural administration and water resources managers in water protection zones. Additionally, the Water Framework Directive and the Nitrate Directive of the European Union are supposed to amend emissions to lower levels. In Germany, the recent inventories of water resources managers / water suppliers, however, showed that all these efforts (particularly concerning nitrogen  from the agricultural sector) had no success so far.

Various strategies are employed or have been proposed to abate, remediate and control soil and water pollution (Tab. 1).

 

4.3      Problems of different time constants and delayed responses

Generally, scientific understanding is slow compared to ongoing processes (delayed response). It can take long time periods between the first release of an anthropogenic chemical to the environment and its detection, scientific investigation, and classification as pollutant in different environmental compartments. For instance, the time requirement for transformation of non or slowly degradable organic pollutants and their transfer from soil to water is a big factor of uncertainty for the assessment of pollution responses. Due to a reduction in sulphur emissions since nearly two decades, e.g. topsoils show today at some places deficiency in sulphur whereas subsoils in contrast show high concentrations of sulphur. Another example is the water tax, which was introduced in some regions in Germany in the late 80ies in order to reduce manure application in groundwater protection zones by paying the farmers for their reduced yields and thus to reduce nitrate emissions to the groundwater. However, the results (no significant reduction of nitrate in groundwater) showed, that a success control of such a measure is maybe not possible within one or two decades and that an expected reduction in concentration will become visible in the long-term (some decades) connected with a strict application and control of the measure.

 

Table 1: Strategies/principles to abate, remediate and control soil and water pollution

Please note that not all measures are equally suited to combat or treat large-scale diffuse pollution (see remarks in the table)

 

Strategy/

principle

Target point

Treatment / Management

Remarks

Curative

hazard elimination

Soil

Soil Exchange

Not realistic for large areas

Bioremediation

Dependent on remediation goal

Immobilisation

Dependent on remediation goal

Soil – Water bodies

Sealing

Can be used for isolated site

 

Insulation/encapsulation

Can be used for isolated site

 

Soil – Plant

Phyto-rhizo-remediation

Applicable only if long clean up duration is available

 

Cultivation restriction

problem of acceptance

Soil – Animal

Grazing restriction

problem of acceptance

 

Plant – Animal

Dilution of fodder

 

Feeding restriction

problem of acceptance

Soil – Human

Land use restriction

problem of acceptance

Plant – Animal – Human

Food quality regulations

 

 

 

Water - Human

Food quality regulations

 

Water treatments

economic limits

Diversion or clean up of water sources

Not realistic for large areas

Bath restrictions

problem of acceptance

 

Water bodies

Aeration of water bodies

not in large bodies of water

Bioremediation

 

Ex-situ treatment

only small bodies of water

 

Strategy/

principle

Target points

Treatment / Management

Remarks

 nutrient, pollutants  preventive

hazard avoidance

 

 

 

 

 

 

 

 

 

 

Pollutants inputs

Eliminate sources of pollution

Emisson control in heatings, industrial facilities and traffic; regulation relating to water recycling, run-off water infiltration, waste water treatment, treatment of bio-wastes etc.

Reduce inputs of pesticides and optimise fertiliser applications according to crop uptake 

Adoption of good agricultural practices, taking into account  ground water protection

Guidelines for the re-use of exca­vated soil and the use of soil-like materials

Quality control; clean-up of polluted materials by means of bioremediation, soil washing etc.

 

Establish trade market excava­ted soils for re-use

 

On principle of end use

 or composion basis (nutrients , pollutants etc.)

Guidelines for use of animal and human waste products

Existing treatments are not sufficient for the elimination of residual pharmaceuticals and substances with endocrine-disruptor properties

 

 

Soil

Immobilisation

Not possible for extended polluted areas, different temporal scale (monitoring is a problem)

Bioremediation

It is possible in case of low level  diffuse pollution

 

 

Soil – Water bodies

 

Rhizofiltration

e.g.  keep site all the year grren (Winter cropping ,use of plants on shore or river banks)

Agricultural equipments and techniques

Avoidance of heavy maschines to protect compaction of soil

 

 

Principle

Target points

Treatment / Management

Remarks

Precautionary principle

avoidance of possible hazards

Soil – Water bodies

Monitoring, thresholds (precautionary values, trigger values action values)

 

 

Soil  – Plant

Phytoremediation

It is possible in case of low level diffuse pollution

Land use regulations

Appropiate cost neutral and viable regulations

 

Soil – Animal

Land use regulations

Appropiate cost neutral and ecological viable regulations

 

Fodder quality control regulations

 

Soil – Human

Transfer factors and absorption in intestine

Problems of hazard assessment

Plant / Animal– Human

Food quality regulations

 

 

Monitoring

Food quality control

Water – Human

Management of catchment areas

 

 

Water treatment

 

Water bodies

Monitoring, thresholds

 

 

 

 

 

Emission

Emission control

 

Regulation of inputs

e.g. restriction on the use of Sewage sludge  in agriculture

Regulation on Waste water treatment

 

Laws on Waste management 

 

Financial measures

 

Ecological measures such as financial state support  for ecological land uses

e.g. Avoidance of chemical inputs where ever possible

Accident cases

 

 

 

 

 

Land-use

Regulation of landuse with respeect to time and space

 

Separation of protected areas

e.g.  groundwater protection zone. Wetlans soil protection zone

Limitation of agricultural land-use intensity

e.g. establish zones for intensive and extensive farming

Compensate farmers for yield re­ductions due to ecological land-use restrictions

e.g. contributions for extensively used meadows

Land management

e.g.  crop rotation

 

Soil

Soil amelioration and fertility improvement

e.g. phytomelioration, liming, fertilisation, soil organic matter management (side effects need to be considered)

Re-use of excavated soils and soil like materials

Quality improvement

e.g.  consideration of rent

 

Soil - market

Quality control  is necessary

 

Soil – Water bodies

Soil pH-increase

Increase of adsorption capacity

 

Soil – Plant

Phyto-Rhizoremediation

Adapt crop rotation schemes

 

 

Soil – Animal

Soil properties and pollution state should be considered in allocating grazing land

 

Plant – Animals

Quality labels for fodder

 

Soil – Human

Aspects should be considered at  planning stage of community development  and development of recreation sites

 

 

Plant / Animal – Human

Food qulatiy control regulations

Use of food quality labels

 

 

Water bodies

Quality control guide values for  waste water discharges into water streams

 

 

Strategy/

principle

Target points

Treatment / Management

Remarks

Sustainable resource management

Maintainance of resources

 

 

General

Indicators to assess the effects of agricultural practices on soil and water quality

Develop specific indicators

Political actions in agriculture and actions to other political areas

 

 

 

 

 

 

Soil

Planning of forest areas

 

Systematic data collection and eva­luation

 

Land use modelling as decision-aid

 

Regional action plans for soil management

Establish soil resource plans

Remediation, reclamation and re-use of abandoned industrial land (brownfields)

 

Sustainable agricultural and forest management practices

E.g. encourage appropriate crop rotation schemes

 

Water bodies

Management at the river basin scale

Thresholds, connection to soil protection

 

 

 

Key publications

 

Commission of the European Communities. 2002. Towards a Thematic Strategy for Soil Protection. Communication from the Commission to the Council, the European Parliament, the Economic and Social Committee and the Committee of the Regions. Brussels, 35 p.

 

European Environment Agency (EEA). 2001. Proposal for a European soil monitoring and assessment framework. Technical Report 61, 58 p.

 

Nitrogen emissions management

·        Pätsch, M.; Walther, W.; Reinstorf, F.; Weller, D.: Development of suitable tools for the management of nitrogen emissions out of soils into groundwater in agriculturally used catchment areas, northern low plain of Germany. Proceedings Congress "Research Basins and the hydrological planning", Hefei City (Anhui), China, 22. – 31. March 2004

·        Pätsch, M.; Walther, W.; Heblack, K.: Heterogenität der Denitrifikation in einem pleistozänen Aquifer der norddeutschen Tiefebene. Tagungsband 10. Gumpensteiner Lysimetertagung, 29./30. April 2003, 125-127

·        Walther, W.; Reinstorf, F.; Pätsch, M.; Weller, D.: Management tools to minimize nitrogen emissions into groundwater in agricultural used catchment areas, northern low plain of Germany. Proceedings XXX IAHR Congress "Water engineering and research in a learning society", Thessaloniki, Greece, 24-29 August 2003, Part B, 747-754

·        Pätsch, M.; Walther, W.; Reinstorf, F.; Weller, D.: Research program and development of a suitable tool to minimize nitrogen emissions into groundwater of a Pleistocene aquifer, northern low plain of Germany. Proceedings workshop "Diffuse input of chemicals into soil & groundwater - assessment & management", TU Dresden, February 26th - 28th, 2003; ISSN 1430-0311, PP. 271-225

·        Mioduszewski, W.; Walther, W.; Diankov, Z.; Querner, E.P.; Fic, M.; Paetsch, M.; Velovsky, G.; Slesicka, A.; Reinstorf, F.; Weller, D.; Radoslavov, S.; Marinov, D.; Nicheva, O.; Roelsma, J.; Zdanowicz, A.:
Develoment of tools needed for an impact analysis for groundwater quality due to changing of agricultural soil use. Proceedings IAH-Conference, Krakow, 2002

·        Walther, W.; Pätsch, M.; Weller, D.; Reinstorf, F.; Harms, E.; Kersebaum, C. (2001): Nutrient loads on a Northern German Sandy Aquifer, reduction Processes, their Distribution and Management tools. XXXI. IAH Congress. New approaches to characterising Groundwater Flow, 10th - 14th September 2001, Munich, ISBN 902651; PP. 677-681

 

Airborn substances, Management

·        Reinstorf, F.; Binder, M.; Walther, W.; Hölscher, J.; Bittersohl, J.; Grimm-Strele, J.: Regionalization of diffuse air born impacts on the basis of data from existing measurement networks in Lower Saxony and Saxony (Germany) – assessment of the suitability of interpolation methods. Proceedings ICWRER Conference 22/7/ - 25/7/2002, Dresden.

·        Walther, W; Reinstorf, F.; Heblack, K.; Cramer, T.; Jankowski, A.:
Handlungsempfehlungen zur Bewertung des Grundwassers hinsichtlich Versauerung, dargestellt an einem Beispiel aus Niedersachsen.
Zbl. Geol. Paläont. Teil I, Heft ½, S. 191-208, Stuttgart, Februar 2001.

·        Reinstorf, F.; Walther, W.; Heblack, K. and Cramer, T.:
Influence of acidification and the connected substance leaching on quality of groundwater in sedimentary rocks of Lower Saxony (Germany) - methods of forecasting. FGR'01 - 3rd International Conference on Future Groundwater Resources at Risk, Lisboa, 25-27th June 2001.

·        Reinstorf, F.; Walther, W.; Heblack, K.; Cramer, T.:
Tools for prognosis of the acidification of aquifers in sedimentary rocks. 6th Scientific Assembly of the IAHS, In: "Impact of Human Activity on Groundwater Dynamics", IAHS Publication no. 269, ISSN 0144-7815, Maastricht 18-27th July 2001.

·        Cramer, T.; Walther, W.; Jankowski, A.; Ochmann, S.:
Saure atmosphärische Deposition und ihre Auswirkung auf Boden, Grundwasser und Wasserversorgung in der Wingst / Niedersachsen.
Wasserwirtschaft 90, 2/2000.

 

 

Policy and regulations

·        Directive of the European Parliament an of the Council establishing a framework for Community action in the field of water policy

·        National soil- and groundwater protection legislation and standards

 

Currently, soil and water protection are still very much focused on regulating pollutant concentrations in soil and waters. Integration of protection efforts must be based on the control and regulation of fluxes between the relevant compartments of the environment and the anthroposphere.

 

Diffuse pollution enters the environment primarily through atmospheric deposition and through agricultural land use. The critical load concept is being developed as a means to control the first. Tools for analogous assessment and control of fluxes arising from agricultural land use have been proposed, but still need to be implemented into practice.

 

Sustainable use of soil functions and waters must be assured by integrating soil and water protection with high priority at an early stage into spatial and natural resources planning. This requires the development and implementaton of adequate planning tools and processes.

 

           

Decision support / management tools

PROTERRA-S: Model for mass flux balancing for regional metal fluxes in agroecosystems

 

Critical load concept

 

Combination of models for flow and substance transport in unsaturated and saturated zones and geochemical reaction models

 

 

Country information / Library

Federal Ministry for the Environment, Nature Protection and Nuclear Safety. 2002. German Federal Government Soil Protection Report. Bundestags-Drucksache 14/9566, PO Box 12 06 29, D-53048 Bonn, Germany, .

 

 

Authors:

R. Schulin, T. Stoll, E. Hepperle, S. Gupta, P. Grathwohl, D. Halm, K.-U. Totsche, W. Walther, C. Konrad

(http://www.uni-tuebingen.de/sowa)

 

           

Who does what?

SOWA – Integrated Soil and water Protection: Risks from diffuse pollution

(http://www.uni-tuebingen.de/sowa)

 

 

 

 

SOWA Working Group “Management options for large scale soil and water pollution incl. environmental economics / socio-economic issues”

Lead: Rainer Schulin (schulin@env.ethz.ch)

Relevant issues relating to large-scale diffusive pollution of soil and water are discussed and a set of priority research gaps including environmental impacts and socio-economic driving forces are identified. The guiding principles and action plans for successful management of extensively polluted soils are inadequate and show many gaps such as:

·        The development of methods for the quantification of soil functions and potentials is recommended since the knowledge about the effects of land use changes on soil functions and potentials are insufficient.

·        The development of instruments for practical applications e.g. in spatial planning and land use planning and hazard maps are needed which show e.g. polluted areas of metal accumulation, mobilisation and type of environmental compartment.

·        The management of pollutant loads in strongly heterogeneous areas (e.g. residential areas) is required and the long-term behaviour of pollutants in deeper groundwater has to be understood.

·        The metabolic reactions, transport and fate of macro nutrients in groundwater have to be determined in order to assess life spans of water works and to take further actions above ground for preventing groundwater-degradation.

·        Suitable tools for the management of land use in groundwater protection zones have to be developed. Management strategies do not only require co-operations of local water suppliers and authorities but also the co-operation of land users in order to succeed.

 

 

 

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