Definitions, strategies and principles for bioindication/biomonitoring of the environment Plan: • • • • Introduction Definitions Examples for Biomonitoring Strategies and concepts Introduction • An objective of prophylactic environmental protection must be to obtain and evaluate reliable information on the past, present and future situation of the environment. Besides the classic global observation systems such as satellites and instrumental measurement techniques like trace gas and on-line water monitoring, increasing use should be made of bioindicative systems that provide integrated information permitting prophylactic care of the environment and human health. • In the last 25 years, bioindicators have shown themselves to be particularly interesting and intelligent measuring systems. As long ago as 1980, Müller considered the “bioindicative source of information” one of the pillars of modern environmental monitoring, since “bioindication is the breakdown of the information content of biosystems, making it possible to evaluate whole areas” (Fränzle et al. 2007). Figure: Environmental media and their bioindication using various living organisms (e.g. mosses, daphnia, earthworms) (Markert 2008). • The application of organism-based surveillance methods (biomonitoring / bioindication) can extend our knowledge of mechanisms which are involved in (matter-based) interactions between the organism and its environment (Wünschmann et al. 2008). Embracing and combining topics and methods from environmental chemistry, toxicology and ecology, ecotoxicology succeeded in characterizing and quantifying effects of chemicals during the last decades by means of novel methods. The mere multitude and diversity of chemicals which make their way into the environment (by 2003 some 5 million compounds were known [Fent 2003], with additional 500-1000 newly introduced compounds per year which then are broadly used) brings about an immense task to ecotoxicology, an inter- and transdisciplinary task which nowadays surpasses the challenges to both human and veterinary toxicology (Fränzle O 1999). • Being a part of environmental sciences, ecotoxicology includes many specific methodological innovations which only in their combination permit to meet societal demands for protection of environment (Oehlmann & Markert 1999). Here, main tasks to be done before novel chemical compounds can be accepted even for laboratory amounts and purposes (biotests; e.g. Fomin, Oehlmann, Markert 2003) include prospective risk evaluations, but also measurements of effects damaging organisms and entire populations in open, “free” environments (the latter achieved by means of bioindication; e.g. Markert et al. 2003a,b). Using organisms of different trophic levels (plants, animals, microorganisms) to determine detrimental effects of chemicals does not represent the only peculiarity typical of both lines of work, but these also differ with respect to statements on the situation of terrestrial and aquatic environmental compartments. • These new stressors usually have a multiplying effect, i.e. they are added to the effects of natural systems, or they themselves act in combination, with the result that the “tolerance level” of the organisms‟ ability to cope or to adjust to them is exceeded. • According to estimates by Schneider (1992), around 2500 square miles of tropical rainforest are being lost at a rate of 1.5 acres per second. • Over 70 square miles of arable land are being irreversibly transformed into desert through mismanagement, overgrazing and over-population. Definitions In the following we will give some definitions summarized in Markert et al. (1997, 2003ff), Markert (2008): • A bioindicator is an organism (or part of an organism or a community of organisms) that contain information on the quality of the environment (or a part of the environment). • A biomonitor, on the other hand, is an organism (or part of an organism or a community of organisms) that contains information on the quantitative aspects of the quality of the environment. • The clear differentiation between bioindication and biomonitoring using the qualitative/quantitative approach makes it comparable to instrumental measuring systems. Such effects (information bits) of bioindicators (biomonitors) may include changes in their morphological, histological or cellular structure, their metabolic-biochemical processes (including accumulation rates), their behaviour or their population structure. • Accumulation indicators/monitors are organisms that accumulate one or more elements and/or compounds from their environment. Effect or impact indicators/monitors are organisms that demonstrate specific or unspecific effects in response to exposure to a certain element or compound or a number of substances. Figure: Illustration of the terms reaction, accumulation and effect / impact indicator (Markert et al. 1997). • According to the paths by which organisms take up elements or compounds various mechanisms contribute to overall accumulation (bioaccumulation), depending on the species-related interactions between the indicators / monitors and their biotic and abiotic environment. • Biomagnification is the term used for absorption of the substances from nutrients via the epithelia of the intestines. It is therefore limited to heterotrophic organisms and is the most significant contamination pathway for many land animals except in the case of metals that form highly volatile compounds (e.g. Hg, As) and are taken up through the respiratory organs (e.g. trachea, lungs). • Bioconcentration means the direct uptake of the substances concerned from the surrounding media, f.e. the physical environment, through tissues or organs (including the respiratory organs). Besides plants, that can only take up substances in this way (mainly through roots or leaves), bioconcentration plays a major role in aquatic animals. The same may also apply to soil invertebrates with a low degree of solarisation when they come into contact with the water in the soil. • Active bioindication (biomonitoring) is meaned when bioindicators (biomonitors) bred in laboratories are exposed in a standardised form in the field for a defined period of time. At the end of this exposure time the reactions provoked are recorded or the xenobiotics taken up by the organism are analyzed. In the case of passive bioindication (biomonitoring) organisms already occurring naturally in the ecosystem are examined for their actions. This classification of organisms (or communities of these) in according to their “origin”. • Various newer methods (biomarkers, biosensors, biotests in general) have been introduced into the application field of bioindication, besides the classical floristic, faunal and biocoenotic investigations that primarily record unspecific reactions to pollutant exposure at higher organismical levels of bioindication. • • • • • Biomarkers are measurable biological parameters at the suborganismic (genetic, enzymatic, physiological. morphological) level in which structural or functional changes indicate environmental influences in general and the action of particular in qualitative and sometimes also in quantitative terms. Examples are enzyme or substrate induction of cytochrome P-450 and other Phase I enzymes by various halogenated hydrocarbons; the incidence of forms of industrial melanism as markers for air pollution; tanning of the human skin caused by UV radiation; changes in the morphological, histological or ultrastructure of organisms or monitor organs (e.g. liver, thymus, testicles) following exposure to pollutants. A biosensor is a measuring device that produces a signal in proportion to the concentration to a defined group of substances through a suitable combination of a selective biological system, e.g. enzyme, antibody, membrane, organelle, cell or tissue, and a physical transmission device (e.g. potentiometric or amperometric electrode, optical or optoelectronic receiver). Biomarkers and Biosensors can be used as biotest (bioassay) which describes a routine toxicological-pharmacological procedure for testing the effects of agents (environmental chemicals, pharmaceuticals) on organisms, usually in the laboratory but occasionally in the field under standardized conditions (with respect to biotic and abiotic factors). In the broader sense the definition covers cell and tissue cultures when used for testing purposes, enzyme tests or tests using microorganisms, plants and animals in the form of single-species or multi-species procedures in model ecological systems (e.g. microcosms and mesocosms). In the narrower sense, the term only covers single-species and model system tests, while the other procedures may be called suborganismic tests. Bioassays use certain biomarkers or – less often – specific biosensors and can be used in bioindication or biomonitoring. • The term tolerance can be described as desired resistance of an organism or community by unfavourable abiotic (climate, radiation, pollution) or biotic factors (parasites, pathogens), where adaptive physiological changes (e.g. enzyme induction, immune response) can be observed (Oehlmann & Markert 1997). Unlike tolerance, resistance is a genetically derived ability to withstand stress (Oehlmann & Markert 1997). This means that all tolerant organisms are resistant, but not all resistant organisms are tolerant. Sensitivity of an organism or community means its suspectibility to biotic or abiotic changes. Sensitivity is low if the tolerance or resistance to an environmental stressor is high, and sensitivity is high if the tolerance or resistance is low. Examples for Biomonitoring • Mosses for atmospheric pollution measurements • In addition to instrumental measuring techniques the use of mosses have long been an accepted method of monitoring human-induced atmospheric inputs of heavy metals and other elements into the environment (Rühling & Tyler 1968; Smodis 2003; Herpin et al. 2004). • • Mosses represent one of the simplest forms of terrestrial plants. This is directly connected with the peculiarities of their water metabolism. The dominant phase of the bryophyte life cycle is represented by gametophyte generation. Consequently, evolution of structural complexity has been partly limited by the dependence of sexual reproduction on free water for the dispersal of the motile antherozoids. • For some ten years now, epiphytic or epigeic plants – mostly mosses and lichens, but also Bromeliaceae (Tillandsia) in Latin America – are being employed as bioindicators, their use being accepted not only in the scientific community but also among political or economic authorities in both Europe and Southern America (Bargagli 1998; Freitas et al. 2000; Pignata et al. 2002; Zechmeister et al. 2003; Markert et al. 2004). This state of matters differs from those in other countries and continents (China, Australia- North America) where plant-based biomonitoring was developed for scientific purposes or on regional rather than national scales (only). Thus no comprehensive description may be given but one has to consider unlike developments of these techniques (Zechmeister 1995; Djingova & Kuleff 2000; Garty 2000a, 2000b; Herpin et al. 2001; Wolterbeek 2002; Djingova et al. 2003, Fränzle O 2003). • This high diversity in developments of bioindication and biomonitoring was not produced arbitrarily but owes to fundamental (and thus acceptable!) reasons (Markert et al. 2008): • - historical ones, with corresponding methods spreading from Scandinavia via Europe to the rest of the world; • - geographical, climatic and geogenic distinctions which influence each living organism and population (hard skills); • - different mental and psychological attitudes depending on intercultural attitudes among scientists of different origins who encounter each other e.g. in international meetings for harmonization and procedures (soft skills). • Results from chemical analysis are converted into multi-color maps (s. figure) of pollution using geographic information systems (GIS), providing maps such as that for lead (moss samples were taken from 1990-1992). • Figure: (a) This map gives Pb contents in moss species from different countries (Netherlands, Germany, Poland), using moss samples taken during 1990-1992 (Herpin et al. 1996). (b, c) Mosses [only two moss species of a total of four of the overall European program are shown as examples: Pleurozium schreberi (b) and Hylocomium splendens (c)] are bioindicators / biomonitors for controlling the atmospheric deposition of different chemical elements. • As final output of such investigations bioindication results compare relative (analytical) data of (element) concentrations given by bioindicator species (mosses). In this example the mosses are represented by different locations around Middle Europe. Same can be done by using bioindicator to get an impression on behavoiur of chemicals by time. As example is given for Pb in mosses (Polytrichum formosum) collected over some years. • Spanish Moss for atmospheric pollution measurements f.e. in megacities like São Paulo, Brazil (Markert et al. 2011) • In the past 10 years more and more activities were undertaken to transfer the bioindication method into the pollution control observations of so called megacities like São Paulo (Figueiredo et al. 2001, 2007; Markert et al. 2011) having around 20 million inhabitants. Smog over São Paulo. Photo was taken by A. Figueiredo. For this reason Tillandsia usneoides L., an epiphytic bromeliad plant, was chosen, because this plant is able to absorb water and nutrients directly from the air (photo by A. Figueiredo). Five consecutive transplantation experiments (8 weeks each) were performed in 10 sites of the city, submitted to different sources of air pollution (industrial, vehicular), using plants collected from an unpolluted area. After exposure, trace metals were analyzed in the plant by instrumental neutron activation analysis. Distribution maps were drawn, which demonstrate that traffic related elements such as Zn and Ba presented high concentrations in exposure sites near to heavy traffic avenues (cars, buses and trucks) and may associated to vehicular sources (Ribeiro et al., 2012). Figure 4. Simplified representation of complex (eco-)system interrelations with regard to a pollutant, and consequences for bioindication and biomonitoring (from Markert, 1996). Figure 5. Possible hierarchical structure of a bioindicative toolbox model for integrative approaches in human- and ecotoxicology. Bioindication and biomonitoring must supply information on the degree of pollution or degradation of ecosystems. For integrative approaches bioindication is not an “environmental monitoring machine” for a specific constellation of factors; ideally, it is an integrated consideration of various bioindicative test systems which attempts, in conjunction with other environmental parameters, to produce a definite picture of a pollution situation and its development in the interests of prophylactic care of health and the environment. Strategies and concepts • • • • • • The following reflects only a very small part of the overall existing and proposed strategies and concepts for bioindication. A great many more details on specific programmes are given, for example, by the Environmental Protection Agency (EPA, US), the OECD and the EEA. Further international and national organisations (the International Standards Organisation (ISO), CH), the European Union (EU, Belgium), especially in its section on “Measurement and Testing” (the former Bureau Community of Reference (BCR, Belgium)), Deutsches Institut fur Normung (DIN, FRG) and others have elaborated various programmes for environmental control, observation and protection which are available on request via literature search or (more effective) via the internet. The future development and coordination of bioindication methods should follow a two-levelled (A and B) parallel line: – Level A optimises the development and harmonisation of existing and new indicators to make them suitable for practical use in risk management. – Level B, already discussed in detail in Figure 4, represents a strongly integrated approach with environmental and health indicators to fill the gap between environmental biomonitoring and human health aspects.
