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The semiotic dimensions of sign interpretation on derelict land are complex and manifold. When writing this lecture, we realised that we can only scratch on the surface of this cosmos of ideas, perceptions and views. We have tried to embrace this intriguing topic by reducing it to basic scientific practice juxtaposed with semiotic implications including a short history of the conceptualization of "contamination", aspects usually not discussed in the process of investigating a derelict site. The result is a sequence of three discourses on waste, two rationales on site investigation complemented with two excurses on maps and soft signs.
Discourse I: The discovery of hazardous wastes (Susanne Hauser)
Not until the prolonged end of the European heavy industry and the end of the most conspicuous emissions connected with it, did public attention focus on the wastes left behind in its wake. The issue of "dangerous wastes from the past", or Altlasten (German), a problem of contamination, was first identified in the 70s as a general problem, and not just as a question of individual instances, in England, France, the Netherlands, the United States, Germany and also Japan.
During that time, the first, since then extended legal instruments for the assessment of hazards and the definition of objects to be protected emerged. The interpretation took place in a time of intensive economic decline in the heavy industry. The problem has been constituted as such since the decline of heavy industrial production, when the old industrial sites began to change hands usually for public disposal, and the question of reuse arose.
The present discourse about what is understood as dangerous wastes from the past - contamination - refers to the remains which are capable of generating undesirable effects if they are not treated.
The discursive effort does not have anything to do with the fact that whatever has been leading to the resulting definitions and actions since the 70s actually did not exist previously: Contamination understood as such today have to some extent been produced over centuries in the areas of early industrialization and have seeped into the soils and water resources without any comprehensive, systematic efforts existing at the time to acquire data, clear, cleanse or secure them.
The consequences of permanent pollution were certainly noticed, however, they were registered as accidents or disease cases. The semi-public discourse in the form of complaints, entries, and public letters about the pollution of rivers, soils and the atmosphere by the industries in the old industrialized countries is as old as some of these remaining substances themselves noticed today as contamination. Observations of changed plant growth, the restlessness and diseases of animals and cases of illness among human beings which could in part be brought into a causal connection with the specific emissions have been frequently made.
Wherever clashes of interests occurred in any of the old industrialized countries there were regulations governing risk and liability rights that could usually be derived from the already existing water and soil rights and had in part to be codified separately as in the case of the mining laws. Historical environmental investigations with respect to industrialization could show for some cases the fact that and the ways in which economic interests asserted themselves successfully in not having to treat those wastes. (See Brüggemeier/Rommelspacher 1987, 1992, Brüggemeier 1995; Brimblecombe/Pfister 1990; Radkau 2002, 274-83.)
During the period of industrial production, considerations of critical substances in the water resources and soils were hardly of any interest even when the facts were known or suspected. In so far, the handling of contamination as it has been developed in the last 30 years can be seen as part of a revelation process involving the old industrial sites.
Franz-Josef Brüggemeier und Thomas Rommelspacher present four reasons for the late attention given to toxic substances in soils: In contrast to the air and water resources, soils were assumed to be part of private property where no intervention should take place; soils seemed to be resilient with respect to pollution; the methods of measurement had not matured sufficiently and, finally, the role of soils within an ecological context had not been fully appreciated until the 70s (Brüggemeier / Rommelspacher 1992, 75).
A final word on the observation of wastes: There are some terms that are repeatedly used in a planning context when dealing with difficult-to-manage industrial remains, burning dumps or toxic substances. These are the terms hazard, safety, security, protection, risk prevention, suspicion, and control. Especially, the last-mentioned term will have to be examined here since hardly a discovery - and it is discoveries and the discourse about them we are concerned with here - has extended the sphere of the observable, determinable and controllable to the same extent as the preoccupation with unstable soils and slopes or toxic substances in water resources, soils and the atmosphere.
Hardly any other circumstance has enlarged the scope of required data acquisition and planning with state-of-the-art expertise to such an extent than the attention given to "hazardous substances" whenever an old industrial site is designated to be reused.
In this connection, a slow, intermittent discussion presents itself in all the old industrialized countries seeking to develop legal and technical definitions for an actual hazard and its pragmatic prevention. In this process, the general term contamination (English/French) or Kontamination (German) as well as the spatial term Contaminated/Derelict Land (British), Brownfield (U.S.), Site pollué (French), Altlast (German) are being constituted as the object or problem, and are leading to further investigations, added data acquisition, and new methods as the now traditional Site Investigation Approach.
Rationale I: Historical site analysis (Dieter D. Genske)
In order to analyse signs of degradation the historic development of a terrain has to be reconstructed. In this context, signs of former use have to be identified and recorded in a systematic way.
Historical site analysis - also referred to as desk study - focuses on the former utilisation of the site and the resulting degradation of the terrain. The main goal of the historical or multitemporal analysis is to investigate and visualise the impact of human activities and their consequences for future utilisation. The historical analysis is based on textual records such as former site investigation reports, environmental audits, building and production permissions, statistical data on products including information on raw materials and wastes, property tax files, land title records, newspaper archives, private documentation, etc.
Nontextual records complement this information. Relevant cartographic documents ranging from cadastral to topographical maps are available for a period of more than 150 years. The cycles of updating these plans and maps have varied from originally 15 years to 3-7 years more recently.
As a result, those sites existing since the 19th century are documented by up to 20 updated editions of large-scale topographic maps (1/25000 and larger) and more or less the same number of plans. Furthermore, additional nontextual documents such as maps of existing and earlier buildings and installations, previous street directions, evidence of water supply and sewage systems, fire insurance maps, safety plans, mining commissions, landuse maps, biotop maps, etc. offer valuable information on the historical development of the site.
In addition, aerial photos serve as a useful source of information to reconstruct the historical development and former utilisation, especially if cartographic material is missing for certain time periods. The earliest coverage in Europe dates from the 1920s. It is supplemented by photography from allied reconnaissance and mapping sorties during World War II and thereafter by air covers taken at regular intervals of 2-3 years since 1950. Consequently, there is an aerial photographic documentation of most sites comprising 15 to 25 and sometimes even more covers, which are available for the historic analysis and mapping of urban land.
Finally, oral textual information from eyewitnesses may explain details of the production, the handling of waste material and the localisation of possible dumping sites.
The most complicated task is harmonising and visualising the essential information. A map depicting former utilisation based on the status quo-map has to be prepared. Of central interest are features which may obstruct the future utilisation of the site, including
o soil- and groundwater contamination and
o relicts of former installations such as massive foundations and underground
constructions.
In order to detect these obstacles, historical maps and aerial photos are analysed, scanned and superimposed with the status quo-map to produce a thematic map depicting the historical development of the site. Buildings and installations that may obstruct the future utilisation are copied into that map as are possible sources of contamination due to activities of production and handling of polluting substances (at train stations, loading sites, etc.), or their deposition (waste heaps, dumping sites, etc.).
An example: The coalmine Minister Stein used to be one of the most productive deep coalmines in the German Ruhr-District. Already in the last half of the 19th century mining commenced and subsequently a variety of processing facilities and chemical plants were founded in direct vicinity. However, due to the coal crisis the mine went out of business in the 1980s. The site was abandoned and became typical industrial wasteland, too contaminated for potential investors. However, the still intact infrastructure of the immediate neighbourhood and the proximity to major Autobahns made it attractive again.
In the late 80s European funds were made available to remediate the site. Eight million Euro were drawn from the European Fund for Regional Development to support the project and plans were made to integrate Minister Stein into the International Building Exhibition IBA Emscherpark. The site became a prominent example for conversion of derelict terrain into high quality industrial land.
In order to assess the hazards related to former use the first step was to prepare the status quo-worksheet illustrating the present situation on the site. After this, historic maps and aerial photos were scanned and significant features were imported into the status quo-document. The scans had to be adjusted in scale and rotated to match the status quo.
Based on the historic maps and building permits the historic development of the site could be reconstructed, i.e. installations and facilities suspected as potential sources of contamination could be identified. Digital layers were prepared representing historical stages of development. Finally, a synthetic map with all relevant historic information was produced (see slide series "Investigation: Desk Study" under http://www.egs-net.ch/mysite/htmls/openlearn.html).
Excursus I: Maps and Signs (Dieter D. Genske)
The analysis of maps with the tools of semiotics has to be considered a new field, although its roots reach back to the times when the first modern maps where drawn, as Bruno Aust, Dagmar Schmaucks and Winfried Nöth point out in their introduction to the edition Landkarten als synoptisches Medium (1998). One can even go back to ancient history to discover semiotic processes in land interpretation: already four centuries BC the Greek physician Hippocrates geo-referenced in his work "On Airs, Waters, and Places" (e.g. Littré 1961) spatial phenomena as signs for health and reasons for diseases. Cartography as "ensemble des opérations de conception, d'élaboration, de dessin et d'édition de cartes" (Petit Larousse 1998) is a semiotic exercise par excellence, a formalised process to visualise phenomena with a complex system of signs.
Even time can be formalised with cartographic signs (Genske & Hess-Lüttich 1998), as realised already by Giordano Bruno (1548-1600), who interpreted from geomorphological signs that (according to Blei 1981)
"…da bald ein Meer ist, wo vorher ein Fluß war, bald sich Berge erheben, wo vorher Täler sich vertieft hatten …Aber in allem möchte ich nichts Gewaltsames zugeben, sondern einen ganz und gar natürlichen Verlauf erkennen. Denn ich nenne nur dasjenige gewaltsam, was außerhalb der Schranken der Natur oder gar gegen sie geschieht."
("… there soon is a sea, where before was a river, mountains rise, where before where valleys … But in all this I would not see anything violent, rather a natural development. Because I only call violent what happens outside the boundaries of nature or even against her.")
However, to put these findings on a map was, in those days, too much to dare when even words were already enough to be executed by the Holy Inquisition as a heretic. Maps, however, would have had a potential to logically explain the relation between time and the surface of the earth with a limited set of signs arranged in a systematic way and a special colour code dating back to Goethes Concept of Colours (Hofbauer 1998).
Cartographic representations with their iconised reduction of complex processes enables the expert to present geomorphological phenomena in such as way that even the layman will understand them. Describing linguistically these complicated processes would mean much more effort, still yielding a puzzling and confusing result. Cartography thus optimises a difficult and interwoven transfer of space-time information.
The process becomes even more complicated if the information to be transmitted is ambiguous or fuzzy, having only a limited truth-value. Fuzzy information are, however, quite common when analysing brownfields, the object of this lecture. Only in few cases it is really clear which activities have caused the contamination of soil or groundwater. Usually there are only hints and speculations about presumed waste pits that where dug informally, not recorded in any official document. War impacts, which have caused pollution and in cases still cause pollution, are only sporadically documented. Even fragments of now dismantled installations such as foundations, cables, sewers, tanks, culverts, etc. are missing in maps and records.
Still, a large variety of information are available that come in textural and graphical formats: description of production processes, statistics and mass flows, company records, building permissions, official surveys, geological maps, exploration boring profiles, aerial photographs, to mention a few. The decisions based on the evaluation of all these information are decisive for the feasibility of the remediation project as they are for the future of the city quarter, possible job opportunities, major investments... Consequently, an optimised strategy to investigate brownfields is needed to identify, record and visualise zones characterised by contamination and underground obstacles (Genske 2003). Since most of the information is fuzzy or soft, a well reflected investigation strategy has to be developed which processes all sorts of information, from crisp data to semi-information of reduced truth-value. We will come back to this point after the following, second discourse on waste.
Discourse II: Contaminations (Susanne Hauser)
Wastes incurring treatment problems have been discovered on industrial wasteland and dump sites since the 70s: Lakes of tar, unlined earth basins filled with naphta products, soils polluted with benzene, toluene, xylene and polycyclic aromatic carbohydrates due to accidents, carelessness or normal operation, for example, during the production of carbohydrates.
Slag, clinker, and construction waste contaminated with dioxines, for example, after the demolition of chimneys pose further categories of possibly critical materials; in former ore mining areas, heavy metals as well as highly toxic metals such as thallium or arsenic can be found. These are substances that are given priority in the discourse about soil damage with undesirable repercussions. An overview of the treatment of "Wasteland areas and land recycling" in various countries, among them Japan, the USA, Canada, can be found in Genske and Noll (1995). A comprehensive display of the aspects considered today when confronted with "Land recycling and contamination" is given by Thein 1995 in the same volume. Here, I am going to focus on the British, and, later on (see Discourse III), the German development.
In the 70s, the institutionalized treatment of contaminated land was added to that of derelict land in Great Britain. This term describes "land that contains toxic substances in such concentrations that they present a potential threat directly or indirectly to man, the environment or to other targets such as building structures or the components of buildings." (Richards 1995, 23)
While derelict land referred essentially to physically describable damage and instabilities, chemical and biological aspects now come into play. The category of contamination is constituted as an object of discourse and as a cause for a new kind of managing practice.
From a semantic perspective, the term describes an interesting option. The common use of the term contamination (Kontamination), and the definition of the removal of the damage, decontamination (Dekontamination), present a suggestive image of that which has occurred and should be reversed:
Something has been infected by something else, made sick or spoiled, contaminated as it were. Thus there was something that was pure and intact and then came into contact with something else and therefore became disrupted in its properties. Decontamination describes the process in which the previous boundary between substances and bodies is reinstated since something which was adulterated in an impermissible and uncontrolled way has been withdrawn again. The fact that this is not always successful, is exemplified by the contamination through radioactive substances.
Speaking about decontamination suggests that there was a process that was reversible. It implies that whatever was brought about in damage in the period of industrial production can be reversed today. The time and consequences of industrial production can be physically cancelled.
Once the discovery and invention of the contamination has taken place, the internal expert discourse about a generalized suspicion begins to focus on the soils and water resources on industrial wasteland and to engender the preparedness for unforeseen, but to-be-considered toxic substances on industrial sites: "In practice, when dealing with industrial land it is never possible to know precisely what contamination exists and where it is" - according to the landscape planner Richard Cass (1994:34).
The generalized interest in substances remaining after production, however, is only slowly mobilizing efforts to acquire data on them. In the mid-80s, it was estimated that there was about 45,000 ha of derelict land to be treated, which means to stabilize it and at least to vegetate it if it cannot be used in any other way.
Later estimates attempting to consider contaminated land raised this amount to twice as much. However, this includes already treated land whose contamination was not considered during the restoration work. In wake of growing attention, increased knowledge, and new issues, increasingly new demands are being placed on the management practice concerning industrial wasteland and deposits from industrial production (Barry 1995:281).
The disclosure of investigation results and the publication of lists as well as registrations of contaminated sites have met and are still meeting with resistance. In 1990 when the British government included the requirement enjoining local government agencies to compile a register of contaminated sites or land uses endangered by contamination into the Environmental Protection Act shortly before its enactment, it brought about a storm of publicized indignation.
The requirement was interpreted as an immediate demand to disclose current contamination on public and private land. Especially the real estate sector and some local administrations quite rightly foresaw a blacklisting effect on sites that would not be able to be sold as a consequence of the register (see Lawton 1994, 18). In almost all old industrialized countries, there is still a more or less restricted right on behalf of property owners to say nothing about the condition of their property, which in turn seemed to be jeopardized by this proposal. The requirement was dropped.
In the United States, the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980 has been aiming in the same direction. With the installation of the SUPERFUND (1999) to clean up contaminated terrain, a National Priority List for the most polluted sites was established. In practise, however, this list had the effect "of causing the site, plus much of the adjacent area, to be abandoned for any use, and severely depressed property values. Therefore (this) listing is avoided by local governments and property developers …" (Williams 1995:22).
However, the obstinate reticence in combination with the realization that hazards could be lurking in the dark elicited curious responses: These ranged from diffuse fears and suspicions and well-founded anxiety to insistent not-wanting-to-know. Since it is publicly known to be possible to find out something about the contamination of areas, buyers and users of a plot now want to know whether or not this knowledge has been taken into consideration: The uncanny feeling following the suspicion can only be rationally abated once the possible knowledge has been acquired. There is now a de facto compulsion to investigate, confront the waste and, as it were, confront what has been previously repressed.
The magazine Landscape Design dedicated a whole issue to the question of contaminated areas in 1994. It describes how a planner from a local government agency in Britain compiled the requirements resulting from the failure of the listing of contaminated land: "... an awareness of the issues; a lack of fear of the problems; an adequate information base; a clear definition of the responsibilities; a fair and easily understood legal framework; adequate resources for investigation and techniques and a short and long term programme of action." (Lawton 1994, 19).
In the case of any knowledge or suspicion of hazardous substances, systematic data acquisition with an added guarantee of comparability has not been practiced until recently even in those countries with comparably high environmental standards and sophisticated data acquisition systems for publicly relevant data. In 1990 only the Netherlands and Denmark were among the countries of the European Community with a systematic method for nation-wide data recording of substances compiled in the listings of Altlasten (see "Brachflächenrecycling" 1993-2000; the home page of the US Environmental Protection Agency http://www.epa.gov ).
The aim to stimulate clean-up work was, however, not achieved with these measures. More by accident, the European Commission finally solved the contradiction of disclosing lists of contaminated sites while at the same time depressing remediation efforts as observed in the case of the US National Priority List: The vicious circle was solved with motivation. Naturally, money is the best motivation. Consequently, the EU has been avoiding any listing but has been giving subsidies to those communities, which presented, together with partners from industry, a remediation project that stimulates regional economic growth while at the same time implements Agenda 21 locally (World Commission on Environment and Development 1987). With this strategy, the EU enforced the notion of a sustainable development while at the same time stimulating new, innovative industries in regions depressed by structural changes as for instance the German Ruhr District, where many contaminated sites were remediated in this context and presented during the International Building Exhibition IBA Emscherpark 1989-99 (see European Academy 1995).
Excursus II - Fuzzy signs (Dieter D Genske)
Signs of contamination are rarely clear and unambiguous. In general, they expose only a certain level of truth. Since terms such as certainty, uncertainty, vagueness, ambiguity, imprecision, fuzziness, variability, soft data, etc., are frequently used in hazard analysis, it is necessary to define the most essential of these notions and their use (Genske D, Heinrich K, 2003).
Webster universal dictionary (1993) defines certainty as follows: something undoubted and inevitable. The same dictionary defines uncertain as follows: ambiguous, vague, doubtful, dubious, equivocal, indeterminate, indistinct, questionable, insecure, changeable, irregular, not steady or constant, variable, etc. This list demonstrates the linguistic or lexical flexibility and vagueness of the spoken language. Zimmermann (1996) states for certainty in a real-world model that "certainty (...) indicates that we assume the structures and parameters of a model to be definitely known and that there are no doubts about their values of their occurrence."
Assuming that hard data is available from field sampling, two principle uncertainties can be distinguished (Blockley, 1980): Parametric uncertainty, i.e. uncertainties in measured values of parameters, in terms of statistical probability, and systemic uncertainties, i.e. non statistical uncertainties.
In context of non-statistical uncertainties, the notion of fuzziness has been introduced by Lotfi Zadeh in 1965. Fuzzy can be described by synonyms: flurry, like fuzz, blurred, (Webster dictionary, 1993) and indistinct (in shape and outline), frayed (Oxford Advanced Learners, 1989).
Fuzzy set theory or possibility theory is a generalisation of the classical cantorian crisp, i.e. dichotomous set theory, and represents a means for manipulating non-stochastic, i.e. non-random uncertainty. In contrast to common crisp mathematical approaches that include probability theory, fuzzy sets allow grades of membership' to a set usually expressed by real numbers between 0 and 1. This concept (Zadeh, 1965) provides a natural way of dealing with problems in which the source of imprecision is the absence of sharply defined criteria rather than the presence of random variables.
However, similar aspects have been already discussed in principle by Aristotle
in his treatise "On interpretation" (Aristole 'On Interpretation',
paragraph 7, translated by E. M. Edghill):
"When […] the reference is to universals, but the propositions are
not universal, it is not always the case that one is true and the other false,
for it is possible to state truly that man is white and that man is not white
and that man is beautiful and that man is not beautiful; for if a man is deformed
he is the reverse of beautiful, also if he is progressing towards beauty he
is not yet beautiful."
Being an extension of two and many-valued logics, the main advantage of the fuzzy approach is its capacity to combine available data, expert knowledge and (subjective) experience in order to mimic real-world conditions more realistically. As an approach to dealing with uncertainties induced by imperfect knowledge, data, and signs of varying intensity it complements other theories such as evidence theory, rough set theory, and probability theory.
However, there is still an ongoing controversial discussion, for instance, between supporters of the fuzzy approach and protagonists of the crisp probabilistic approach. The debate reduces to the question, whether fuzziness would be just probability in a clever disguise (Bezdek, 1994). However, it can be stated that the philosophical and academic controversy, as necessary as it is, clearly has been passed by successful fuzzy applications. Fuzzy mathematics is especially applied in industrial controlling, in rule based Fuzzy Expert Systems (FES) in medicine or economy and increasingly also in environmental and geoscientific modelling.
Just as the classical (crisp) set theory serves as the basis for classical logic, fuzzy set theory is the basis for fuzzy logic. This means that theoretic operations in fuzzy sets are the base for logical operations (Alvarez Grima et al., 1997). In contrast to the classical set theory, a fuzzy set consists of objects that can have a partial degree of membership in a set. The classical set theory instead, deals only with binary statements such as yes/no, true/false, or 0/1. Hence, these so-called crisp membership degrees to a set are either equal to 1, if an element belongs to a set or 0, in case of exclusion.
Fuzzy set theory generalises the concept of crisp set membership by extending the range of the characteristic function to the unit interval of [0,1]. The membership function ?A(x) is called the grade of membership of x in a fuzzy (sub-)set A, that lies within the universe of discourse X. In normalised fuzzy sets, the membership degree can take partial membership. Larger values denote higher degrees of membership.
Fuzzy sets are defined by their membership functions, which are therefore the core of the entire concept. There are three possibilities to represent fuzzy sets:
? Representation in a continuous domain, i.e. analytically defined by their
membership functions
? Representation in a discrete domain as value pairs
? Graphical representation.
Examples of continuous piece-wise linear functions are of trapezoidal and triangular shape and examples of continuous piece-wise exponential membership functions are the L-, ?-, ?- and ?-(Gauss-) functions: These standard membership functions are only an approximation of the way humans linguistically interpret real values. Studies in psycholinguistics showed that piecewise exponential functions proved better performance in complex systems (such as language and perception) than more simple linear ones (Altrock, 1995). Therefore, they are considered to describe environmental systems better, i.e. more organically.
These basic membership functions are the basis of fuzzy sets within fuzzy subsets such as quantities, toxicity, size, etc. Fuzzy subsets can, for example, describe certain properties of observed items in an aerial photography. In a study on a derelict harbour terrain (Genske, Heinrich 2003) up to three fuzzy subsets form a fuzzy family, that is a thematic group, such as material, with the subsets toxicity and quantity. Altogether, fuzzy families constitute the fuzzy power set describing the universe of discourse, including the potential to codify spatial signs of contamination.
In this context a Soil Assessment Fuzzy Expert System (SAFES) has been developed to process signs of contamination from aerial photos taken at different time steps (Heinrich 2000). The outcomes of a SAFES consultation is coded in contamination potentials related to observed items, such as installations, surface discolorations, necrotic vegetation, etc. The development of the knowledge-and-rule base of SAFES is based upon characteristics of environmental relevant signs, the specific range of features (spatially and temporal), their relative intensity, as well as a semantic code for description of the observed items. The semantic descriptors helped to define values, shape, and number of membership functions over a certain part of the universe of discourse.
Fuzzy sign processing enables the expert to visualise phenomena that are much too complex to be presented in textual form. It optimises interpretation processes of a manifold nature. Keeping in mind that a conventional preparation of hazard maps calls for a substantial budget (field work, laboratory analyses, etc.) it can be concluded that fuzzy sign processing offers an attractive alternative to analyse degraded urban land.
Discourse III: The German approach - The Altlast (Susanne Hauser)
In Germany, the first public attention given to problematic wastes on old industrial sites neither arose from any systematically sought-for and developed knowledge nor the from the preparedness to take action on the part of the government agencies. Here too, examinations of sites with respect to possible restrictions of use were undertaken in connection with the late consequences registered as accidents.
In Germany, broader public attention to what is understood as Altlasten developed when agencies were groping for explanations for inexplicable events such as the contamination of settlements built on old industrial land. Just as in the Love Canal Case, which finally led to the US Superfund Legislation (Lecture 1), the discussions were triggered also in Germany via so-called inhabited Altlasten. Among the examples are the settlements of Hamburg-Stolzenberg, Bielefeld-Brake, or also Dortmund-Dorstfeld, Herne-Baukau or Essen-Zinkstraße known since 1979. In Northrhine-Westphalia more than 10 percent of the "areas of suspected wastes from the past" were built up in 1991 (Grosser/Schmidt 1994:14).
The German term to a great extent corresponding the English contamination and used in legal as well as non-specialized public discussions is Altlast (dangerous waste from the past). In the first (German) federal soil protection law passed in 1998 Altlasten are defined as "old deposits and old sites causing harmful changes to the soil or other hazards for the individual or the general public." In this law as in the diverse definitions of the laws of the Länder (states) two concepts are pivotal, viz. those of hazard and harm, both criteria which appeal to eco-toxicological evaluations.
This definition can already be implicitly found in the special report of the German Council of Experts for Environmental Issues "Sondergutachten des Rates von Sachverständigen für Umweltfragen" of 1989, published in 1990: "an old deposit or an old site from which hazards to the environment especially to public health are to be assumed or expected". The German Federal Soil Protection Law, published on March 24, 1998, adopts these definitions in its 3rd part, 11-16.
The term "dangerous waste from the past" like the discourse about contamination certainly involves normative connotations. In dealing with them we are concerned with burdens. In a narrower sense it is a legal term, in a less specialized sense it is a term that by all means expresses a negative interpretation: Altlasten entail pollution stemming from closed processes and are now understood in terms of fault, damage, obstacle, or hazard and are addressed as a problem of law enforcement.
What immediately crosses our mind when speaking about old burdens (German: "Alt"-Lasten), is the fact that the liability for cannot be traced and is usually not relevant for the transfer since, with the exception of mining in connection with mining laws, no claims, responsibilities, or ensuing actions can be derived. The slow integration of Altlasten into public discourse is also shown by the fact that, until spring 1998, there was no law in Germany which regulated the definition, data acquisition, responsibilities and the treatment of substances of this kind comprehensively on a nation-wide basis; this law finally makes land owners and perpetrators liable. And not until the recent years, have state laws been developed containing explicit regulations for the crucial legal concepts concerning the treatment of Altlasten.
I have to stress here, that Altlasten are only assumed to comprise substances and sites located on areas that have been given up, however, not the possible deposits on areas that are still in use - these are only included in exceptional cases, and treatment through public agencies is only considered when a hazard to the public has been ascertained.
In Saarland where an average of two areas of suspected contamination per square kilometre are to be found according to the records in 1996, a law of this kind was not passed until June 1994. The reflection prior to this and the practical consequences drawn from this, shown here by an agent of the Saarland environmental ministry, serve as an example of the development that is gradually taking place in steps of performed quantification, definition, data acquisition, and finally, qualification as contaminated areas: "The first approaches towards a systematic and state-wide stock-taking of the old dump sites of the communities, commercial and industrial facilities in Saarland reach back as far as 1965.
The aim of this data acquisition, however, was only to determine the areas of deposits in quantitative terms; no assessments of the hazards were performed. Based on these first activities as well as on a survey of 1400 plants in Saarland carried out by the LfU (Landesamt für Umweltschutz, S.H. - akin to the EPA on a state level) in 1980 designed to survey deposit locations with respect to production-specific wastes, the communal waste treatment association Kommunale Abfallbeseitigungsverband (KABV) supported by the LfU published a study in 1984 which dealt with the environmental hazard potential of all of the 738 old dumps known in Saarland until then.
With the help of an evaluation key based on a point system, an assessment of the possible environmental hazards or Altlasten was carried out for the first time on a state-wide level with special consideration of the deposited material, the distance to water protection zones, water supply plants, surface water bodies, and housing areas, etc. On the basis of this information, the systematic development of a Saarland old-deposit land register Altablagerungskataster (ALKA) was begun with in 1986.
"Due to an intensive study of the records, the questioning of local people with knowledge of the area, but also through the evaluation of topographical maps and aerial photographs, the number of recorded old deposits was more than doubled from 738 in 1984 to 1801 at present. ... The development of the Saarland old site land register Altstandortkataster (ALSTOR) was begun with in fall 1990. ... In the historical survey of old sites only those former sites of potentially hazard-suspected industrial and commercial businesses were considered whose areas were no longer used in a way to cause suspicion at the time of the survey." (Sobich 1996, 6ff)
The preoccupation with Altlasten has been picking up momentum in Germany since 1989. In the new federal states (neue Bundesländer) the heavy industry suffered a breakdown after the fall of the Wall. The mass of suddenly available industrial land that was difficult to sell not only mobilized data acquisition but also considerations to initiate clean-up treatment as a necessary precondition for future economic development.
During that time, concentrated efforts to define the object and to create the necessary legal and funding instruments were made. This did not only accelerate the awareness process concerning Altlasten and their systematic data acquisition in the new and old federal states, but also lead to the designation of 21 major projects for clean-up treatment with respect to such wastes in the new federal states. They were going to require 6 billion German Marks in clean-up costs according to estimates publicized in 1994 (Federal Environmental Ministry 1994, p. 26).
In 1988, between 42,000 and 48,000 suspected areas were identified in the old federal states (Henkel 1988, 18ff). At the end of 1993, almost 140,000 areas and suspected areas with Altlasten were recorded in Germany based on diverse criteria. In 1994, it was estimated that a total 240,000 areas and suspected areas of varying sizes with Altlasten were to be found; at the end of 1998 the estimation went up to 300.000 sites (Federal Environmental Ministry, 1994, 7; Grosser/Schmidt 1994, 13; Freier et al, 1)
The registration of these areas can be interpreted as an extension of the definition and control over areas that had not previously been defined or controlled. In so far, the discourse about Altlasten highlights the efforts to catch up with the realities, which seems to generally characterize the state of waste management today: Added to the concept of risk prevention, is the objective to recycle wasteland and to reuse land understood as a resource. A scope of necessary control is also defined exceeding any previously known controlled containment of wastes.
Rationale II: Hazard Assessment (Dieter D Genske)
Once the historical analysis (or desk study) of a degraded site has been concluded, a field reconnaissance is conducted. Field reconnaissance aims at confirming the findings from the historical analysis in the field. Additional information relevant for the project is collected and simple index tests on ground properties are carried out.
An integral part of the field reconnaissance work is the identification of zones that are homogeneous with respect to certain properties. Field reconnaissance work thus includes a description of:
o The ground conditions, i.e. the types of ground (soil/rock), the mechanical
properties of the ground and the hydraulic properties of the ground.
o The flora and fauna that has established on the site and its relevance to
soil types, depth to groundwater table, ground movements (slope creep, subsidence,
etc.) and contamination of the ground.
o Features of human impact confirming the former and present use of the site.
Thematic maps with data from the field reconnaissance work illustrate problematic ground conditions and redevelopment obstacles. The field campaign is summarised in an interim report in which the results are commented and interpreted. Based on these findings the feasibility of a possible redevelopment project can be assessed. According to the recommendation of the reconnaissance report the project may have to be modified or, in certain cases, even discarded. If the project, however, appears feasible, the field reconnaissance report serves as reference to prepare the next step: the field investigation.
The aim of field investigation is to optimise information on the condition of the site and thereby minimise remediation costs.
In this final stage of site investigation much prior information is available since both historical analysis and field reconnaissance have already been concluded. It is now better known where ground contamination is likely. Some contamination spots have already been confirmed in the field. Derelict buildings have been investigated and sectors where underground structures can be expected have been mapped. This allows a well-considered choice of field investigation measures, which are more sophisticated but also more expensive than the index tests of field reconnaissance.
It is evident that a sound knowledge of the geology of the site, a comprehension of the desk study and the field reconnaissance results and profound experience is necessary to lay out an adequate field investigation campaign. Some sectors of the redevelopment site may still be little known despite the preceding desk study and field reconnaissance work. In this case, the sampling strategy depends on the type of search target and whether discrete ones like underground structures or gradual ones like a groundwater contamination are to be investigated. The search pattern to be applied varies accordingly.
A large variety of methods to explore and characterise ground conditions has been developed:
o 1D-investigation, i.e. linear investigation like borings; 2D-investigation,
i.e. area investigation like geophysics; 3D-investigation, i.e. spatial investigations
like pumping tests.
o Direct investigation or indirect investigation: borings, for instance, are
direct measures whereas geophysical investigations, cone penetration tests,
etc. are indirect methods.
o According to the goal of the investigation campaign, addressing either the
general ground conditions, or the hydrogeology, or the stress and strain characteristics
of the ground, or the contamination of the terrain.
An integral part of the site investigation on derelict sites is the analysis of hazards associated with the reuse of the terrain. On abandoned land a large spectrum of pollutants can be encountered. The hazards caused by these contaminants depend on the existence of contamination pathways, the exposure of the receptor (plants, animals, humans, goods such as the groundwater), its capacity to take up contaminants, the exposure time and the dose. In a real world scenario it is difficult to take into consideration all these parameters at a time.
When soil or groundwater samples are taken and analysed, concentrations of different contaminants are measured. These concentrations can be evaluated according to simple rating systems as for instance proposed by the Dutch recommendations, which consider three threshold values:
o The background value, giving the natural concentration of the contaminant.
o The test value, indicating the need for further site investigation if exceeded.
o The intervention value, calling for immediate decontamination measures if
exceeded.
Threshold values are listed in reference tables. In certain countries, the future utilisation of the site is taken into consideration when defining thresholds. For instance, derelict industrial wasteland may be fit for use as sports ground but not as kindergarten terrain. The fitness-for-use concept has been introduced to reduce remediation costs and to stimulate the re-integration of abandoned land into the urban infrastructure. Threshold values and fitness-for-use values are revised frequently, while research on toxicological impacts evolves constantly.
While hazards refer directly to the probability of occurrence of an adverse phenomenon such as contamination, risk is defined as this probability of occurrence times the consequences arising from the given hazard. Therefore, in order to assess risks the consequences have to be quantified. This is, however, in general not possible, especially if goods are under consideration of which the value can hardly be assessed, as for instance human health.
To simplify hazard assessment for urban land, the danger caused by ground contamination
can be visualised with three key parameters (BUWAL 1994):
o The contamination potential, i.e. the toxicity of the pollutant detected.
o The mobilisation potential, i.e. the potential of the pollutant to find a
contamination path to a possible receptor.
o The potential of exposition of the receptor, i.e. the good to be protected.
These three parameters define three Cartesian axes. On these axes the potentials are scaled from zero, i.e. no hazard potential, to 1.0, i.e. full hazard potential. The potentials may either be assessed intuitively or calculated with more complex evaluation techniques. Maximal hazards are thus represented by a cube, whereby partial hazards produce a smaller volume.
Today, a variety of different hazard assessment procedures have been developed all over the world (e.g. CARACAS 1998, 1999). In most cases the hazard assessment is based on the identification of contamination grade, mobilisation potential, the exposition of goods to be protected, the identification of source-path-target-patterns and the definition of threshold values.
Hazards can be mapped by taking soil and water samples and measuring their grade of contamination. The results can be plotted as point information on a map depicting the contamination intensity. Contour lines of equal contamination grade can be drawn. Once the spatial distribution of contaminants is visualised, potential hazards for the groundwater to be protected, human health, neighbouring ecosystems, etc. can be derived.
Besides the contamination of the derelict site the physical disturbance of the ground may obstruct the redevelopment of the terrain. On industrial sites a complex pattern of buildings, installations, traffic connections and supply facilities is present, which has modified the natural ground conditions. Key aspects are:
o Disturbance of the natural ground conditions by foundations, basements, tanks,
culverts, creating a highly inhomogeneous ground referred to as urbic anthrosols
o Sealing of the ground with roads, parking lots, and constructions, resulting
in a reduction of infiltration of rainwater and thus a reduction of the natural
recharge balance of the groundwater.
Once the natural ground conditions have been altered, the physical behaviour diverts from the one expected on virgin ground. Soft brought-in soils or waste may be located right next to sectors of natural soil. After buildings have been dismantled, the foundations are almost always left in the ground. On industrial wasteland, these foundations can attain considerable dimensions. If they stay in the ground, they obstruct the redevelopment of the site by blocking future cable and sewage lines. They complicate excavation and, if left in the ground, cause differential settlement of new buildings.
Consequently, the investigation of hazards on derelict industrial wasteland not only refers to chemical contamination, but also to physical disturbance. The systematic collection and analysis of all information, crisp ones as well as soft ones, finally leads to the hazard assessment, which is usually presented in the form of a hazard map where hazard levels are coded and zoned in a comprehensive way, so that everybody involved in the remediation project can understand the specific legacy of the site and the threads a future utilisation will bear.
Remark
A first version of the ideas expressed in Susanne Hauser's texts has been published
in Hauser (2001). The ideas presented in Dieter Genske's texts are developed
in more detail in Genske (2003) and Genske / Heinrich (2003).
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