UMWELTSCHUTZ 102 CHIMIA 49(1995) I'\r. 4 ('\pril) Chimia 49 (/995) 102-109 scribing in detail the primary to quater- © Neue Schweizerische Chemische Gesellschaft nary structures of proteins, polysaccha- /SSN 0009-4293 rides or DNA, and of even more compli- cated structures like biological membranes, even though such achievements were con- Biophysical Environmental sidered as impossible at the beginning of the century. Thus, undoubtedly, environ- Chemistry: A New Frontier for mental chemistry will succeed in describ- ing the components and structures that Chemistry play key roles in environmental processes. However, to achieve this as much time and effort as have been put in other disciplines Jacques Buffle*, Montserrat Filella, and Jingwu Zhang will be required and new sophisticated technologies and concepts should be de- veloped. In particular, it is crucial to real- Abstract. The paper discusses the position and role of environmental chemistry among ize that environmental chemistry (like bi- the other environmental disciplines. It discusses the various aspects of environmental ochemistry) is more than just an applica- chemistry and emphasizes the need for developing fundamental studies in biophysical tion of 'classical' chemistry concepts and environmental chemistry in order to better understand the functioning ofenvironmental methods. Most of the latter have been systems. These systems include a large number of various structures in the nanometer developed for chemical systems composed to meter range which play key roles on compound fluxes and consequently on the of small molecules, often with only few homeostasis of ecosystems and on their disturbance by anthropogenic activities. Both components. Similarly, most analytical structures and fluxes are presently ill-known and new concepts and methods must be techniques have been developed for ho- developed in this field. For chemistry, this is a challenging area where supramolecular mogeneous systems, so that, physically structures and processes play dominant roles. It is also a challenging field for the complicated systems should initially be development of environmental sciences since detailed and sound physico-chemical transformed (by preliminary steps such as processes are needed in macroscopic modeling of compound circulation in ecosystems. filtration, dissolution of solid phases or In addition, teaching this discipline to chemistry students would allow them to confront extraction) into well homogenized sys- complex, structured real systems. This paper also discusses the relationship between tems in order that meaningful interpreta- biophysical environmental chemistry and the other environmental disciplines within tion of data be possible. Although such a integrated multidisciplinary studies. The structure used at the Faculty of Sciences of the 'classical' chemical approach has been University of Geneva to favour a flexible but efficient integration is briefly described. and is still useful in environmental scienc- es, it is not sufficient to understand the chemical basis of environmental system 'If you ask a chemist to find for you what biochemistry have passed through long functioning which largely depends on a dynamo is, the first thing he would do is descriptive periods in which important physico-chemical processes based on the to dissolve it in hydrochloric acid' (ALbert discoveries allowed deducing structures existence of biological and physical struc- Szent-Gyorgyi, 1893-1986; biochemist, and properties of elements and compounds. tures and of corresponding concentration Nobel price of Medicine 1937). This led to quantitative formulation of gradients and fluxes of compounds. This modem concepts allowing predictions to is again exemplified by means of the anal- be made on compound reactivity. Where- ogy with biological systems: the chemical 1. Introduction as descriptive phase in chemistry has prob- analysis of a homogenized biological cell ably reached its pinnacle, in biochemistry gives some information on its composi- Not all scientific disciplines have still a great deal has to be done. This lag is tion, but little on its functioning. reached the same stage in their develop- due to the greater complexity of the sys- The main goal of this paper is to em- ment. Today, environmental chemistry, as tem studied and, particularly, to the key phasize this particular aspect of environ- rational discipline, parallels the emergence role played by supramolecular organized mental chemistry which may be less fami- of biochemistry (formerly called biologi- structures. liar to the reader and which is called here- cal chemistry) in the first half of the present Environmental chemistry deals with after 'Biophysical Environmental Chemis- century. Achievement of scientific knowl- even more complicated systems than bio- try' to suggest the important role of su- edge includes several steps: formulation chemistry and it is a much younger disci- pramolecular physico-chemical structures of concepts, collection, classification, and pline. Therefore, despite the development and their links with biological activity. interpretation of data, and generalization of modem sophisticated analytical tech- We believe that this aspect of environ- and formulation of new more rigorous and niques, it is still at its infancy, i.e. much mental chemistry should be significantly quantitative concepts. Both chemistry and work has still to be done on experimental more developed to allow ultimately effi- data collection and classification. Let us cientenvironmental protection. To clearly think for instance about sediments, soil point out the peculiar features of this as- *Correspondence: Prof. J. Buffle aggregates or humic compounds which pect of environmental chemistry, we com- Groupe de Chimie Analytique et Biophysico- are key environmental components but pare it with 'classical' environmental chimique de l'Environnement (CAB E) whose rigorous chemical description is chemistry based on the application of well- Departement de Chimie Minerale, extremely difficult. This enormous diffi- established general chemistry and chemi- Analytique et Appliquee Universite de Geneve culty does not mean that rigorous descrip- cal analysis concepts to environmental Quai Ernest Ansermet 30 tion of environmental systems is impossi- systems. The term 'classical' chemistry is CH-121] Geneve 4 ble: biochemistry has succeeded in de- used here for the sake of clarity to distin- UMWELTSCHUTZ 103 CHIMIA 49 (1995) Nr. 4 (April) guish it from 'biophysical' chemistry. This comparison should help to understand the .- Environmental microbiology - role of environmental chemistry amongst --- Geochemistry, ecology, hydrogeology ~ the other environmental sciences as well Environmental chemistry as one of the chemical disciplines, which Spatial may bring new challenges to the develop- scale ment of chemistry. We will discuss here • co Mathematical mostly this latter aspect and put 'classical' c CI) :CE modelling chemistry and biophysical environmental c<l> _CI)tIl- chemistry in perspective with one another. CI):>' <1>_-CI) "0 til r::- Molecular + microscopic Macroscopic + global ",c<I> iiiE processes 1 processes 2 2. The Place of Environmental 13eE'- til 1; Chemistry in Environmental Sciences "0<1> c_ ~ Environmental ~ ~o analytical chemistry 4 A simplified but useful representation discriminates between three aspects of all co til c- environmental natural sciences (Fig. 1): .-"0='" """'----------------------_/ ~~{co , the fundamental understanding of the func- ,!!lo. ~o Anthropogenic effects tioning of unperturbed environmental sys- "0<1><1>_ co on environment 3 tems (boxes 1 and 2), and the understand- ;:)- ing of anthropogenic perturbations on these systems (box 3).lt is essential to make the Fig. 1. Different aspects covered by environmental natural sciences distinction between aspects 1 and 2 on the one hand and 3 on the other: anthropogen- far the most widely used. In particular, ing (box 3). Obviously, since chemistry ic perturbations cannot be understood and such approaches are the ones applied to influences many geological and biologi- controlled without a preliminary under- quality monitoring in governmental insti- cal processes, these methods are required standing of the behavior of unperturbed tutions. As mentioned above, they have not only by chemists but also by most ecosystems (see below the analogy with their usefulness but environmental chem- other environmental scientists. Analytical medicine, Fig. 2). A major role of environ- istry should not be restricted to this classi- chemistry has thus a key role to play in mental chemistry, therefore, is to study the cal approach, as it is not sufficient to almost all aspects of Fig. 1.Because of it, physico-chemical processes occurring in provide the necessary concepts and infor- a common idea is that the development of unperturbed environmental systems. mation for developing predictive models analytical methods for environmental qual- It is also useful to discriminate be- of ecosystem functioning. Complementa- ity control is the major role of environ- tween environmental 'microprocesses' ry studies on molecular and microscopic mental chemistry. This notion is not cor- (occurring at small scales: nm to mm; box structures and related processes (box 1), rect, as itcan be understood by the analogy I) and 'macroprocesses' (large scales: mm i.e. biophysical environmental chemistry, between environmental and medical sci- to km; box 2) corresponding to whole are required. They need long-term