A Biosystems Approach
E-Book, Englisch, 746 Seiten
ISBN: 978-0-12-407897-0
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark
Professor Daniel A. Vallero is an internationally recognized author and expert in environmental science and engineering. He has devoted decades to conducting research, teaching, and mentoring future scientists and engineers. He is currently developing tools and models to predict potential exposures to chemicals in consumer products. He is a full adjunct professor of civil and environmental engineering at Duke University's Pratt School of Engineering. He has authored 20 environmental textbooks, with the most recent addressing the importance of physical principles in environmental science and engineering. His books have addressed all environmental compartments and media within the earth's atmosphere, hydrosphere, lithosphere, and biosphere.
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Chapter 1 Environmental Biotechnology
An Overview
Abstract
This chapter is an introduction to environmental biotechnology, beginning with a discussion of systems theory. The systematic approach is applied to environmental science and engineering, especially environmental risk assessment and management, including lessons learned from environmental impact statements and life cycle analyses (LCAs). Important tools and concepts are introduced, including biomarkers, the exposome, dosimetry, toxicokinetics modeling, bioremediation, risk trade-offs, and ethics. The chapter introduces both the applications of biotechnology for environmental purposes and the possible adverse environmental implications of biotechnologies. Keywords
Aerosol; Antibiotic resistance; Benefit/cost ratio; Bioengineering; Bioremediation; Biotechnology; Comprehensive Environmental Response, Compensation and Liability Act (CERCLA); Dual use; Engineering ethics; Environmental assessment (EA); Environmental ethics; Environmental impact statement (EIS); Exposome; Exposure assessment; Genetically engineered (GE); Genetically modified organism (GMO); “Gray goo”scenario; Life cycle analysis (LCA); National Environmental Policy Act (NEPA); Particulate matter (PM); Phytoremediation; Precautionary principle; Reliability engineering; Risk analysis; Risk assessment; Risk management; Risk trade-off; Superfund; Systems theory; Toxicokinetics As industrial biotechnology continues to expand in many sectors around the world, it has the potential to be both disruptive and transformative, offering opportunities for industries to reap unprecedented benefits through pollution prevention. Brent Erickson (2005) [1] Two of the important topics at the threshold of the twenty-first century have been the environment and biotechnology. Erickson succinctly yet optimistically characterizes the marriage of potential simultaneous advances in biotechnology and looming environmental problems. Considered together, they present some of the greatest opportunities and challenges to the scientific community. Biotechnologies offer glimpses into ways to address some very difficult environmental problems, such as improved energy sources (e.g., literally “green” sources like genetically modified algae), elimination and treatment of toxic wastes (e.g., genetically modified bacteria to break down persistent organic compounds in sediments and oil spills), and better ways to detect pollution (e.g., transgenic fish used as rapid and real-time indicators by changing different colors in the presence of specific pollutants in a drinking water plant) [2]. Tethered to these arrays of opportunities are environmental challenges that remain unresolved and perplexing. Many would say that advances in medical, industrial, agricultural, aquatic, and environmental biotechnologies have been worth the risks. Others may agree, only with the addition of the caveat, “so far.” Still others would completely disagree, given the uncertainty and potential for severe and irreversible damage to the environment and public health. This text does not argue whether biotechnologies are necessary. Indeed, humans have been manipulating genetic material for centuries. The main objective here is that, given the possible, often unexpected, adverse environmental outcomes from even well-meaning, important, and even necessary biotechnologies, decisions should be systematic in terms of potential risks and benefits. Environmental biotechnology, then, is all about the balance between the applications that provide for a cleaner environment and the implications of manipulating genetic material. The systems approach to biotechnology should indeed be applied to any environmental assessment. An assessment is only as good as the assumptions and information from which it draws. Sound science must underpin environmental decisions. The various scientific disciplines differ in their expectations and applications of environmental biotechnology, including most disciplines of physics, chemistry, and biology. Although each may be correct, they are not solely sufficient to inform environmental decisions. Thus, characterizing properly the risks and opportunities of environmental biotechnology requires the expertise of engineers, microbiologists, botanists, zoologists, geneticists, medical researchers, geologists, geographers, land use planners, hydrologists, meteorologists, computational experts, systems biologists, and ecologists; not to mention the ethicists, theologians, and experts from the social sciences and humanities to consider aspects outside of the typical realms of the physical and biological sciences. Emergence and Biochemodynamics
Even the simplest biosystem involves myriad physical motions, chemical reactions, and biological processes. These processes occur simultaneously in space and time, and may interrelate. They occur at every level of biological organization. Mass and energy exchanges are taking place constantly within and between cells and at every scale of an ecosystem or a human population. Thus, biochemodynamics addresses energy and matter as they move (dynamics), change (chemical transformation), and cycle through organisms (biology). A single chemical or organism changes chemically and biologically, from its release to its environmental fate. The flow in Figure 1.1 applies to ecosystem condition and human health. For example, if the metal and its compounds enter the food chain, they may alter ecosystem functions and structures, e.g., the metals are included in nutrient cycling (function), which may change the growth and survival of certain species, even changing the types of plants in the ecosystem (structure). Although these are ecosystem processes, the metallic compounds in the plants may enter the diet of human populations when these plants are harvested and consumed.
Figure 1.1 Biochemodynamic pathways for a substance (in this case a metal [M] and its compounds). The fate is mammalian tissue. Various modeling tools are available to characterize the movement, transformation, uptake, and fate of the compound. Similar biochemodynamic paradigms can be constructed for multiple chemicals (e.g., mixtures) and microorganisms. Source: Adapted from discussions with Mangis D, U.S. Environmental Protection Agency in 2007. Systematically applying the principles of the physical, chemical, and biological sciences is biochemodynamics. Although this term is relatively new, the phenomenon has been observed since ancient times. For example, even before photosynthesis was understood as a biological process, farmers knew that a plant would grow if exposed to water and sunlight; but also if manure were worked into the soil, the growth would increase beyond what could be attributed to the soil nutrients. As evidence, van Helmont's seventeenth century experiments correctly observed an increase in biomass of a potted willow (Salix spp.) with only rainwater added over a five-year period. He incorrectly attributed the increase solely to water nutrients, not to those in air [3]. This was later corrected by Priestly's eighteenth century oxygen experiments [4,5] and by Ingen–Housz's light experiments [6], which set the stage for Van Niel's work finally documenting the correct reactions known as photosynthesis [7]. Thus, scientists can be aware of biochemodynamics even if they are wrong about the specifics. Indeed, much of the biochemodynamics at work in complex systems resides in the metaphorical “black box.” In keeping with Aristotle's observation that the whole can be greater than the sum of its parts, farmers must have observed that a plant would indeed grow beyond what could be explained by physics and chemistry alone. This seems antithetical to the first law of thermodynamics, i.e., that there must be a balance of mass and energy. I would like to think that Aristotle and Newton would not be at odds, but are expressing nature from two perspectives, both correct. Aristotle's “greater than” is actually an expression of synergy. Aristotle's Metaphysics puts in this way: To return to the difficulty which has been stated with respect both to definitions and to numbers, what is the cause of their unity? In the case of all things which have several parts and in which the totality is not, as it were, a mere heap, but the whole is something beside the parts, there is a cause; for even in bodies contact is the cause of unity in some cases, and in others viscosity or some other such quality [8]. The foregoing discussion introduces the concept of “emergence,” a central theme of systems theory. In systems theory, Aristotle's concept of parts are often referred to as “agents” or “components.” The “whole” requires all of the agents, but is more. Life requires chemistry and physics, but is more. For example, the water molecule depends on the properties of hydrogen and oxygen, but is more. It depends on these atoms, but also the interaction among the atoms. In turn, living things...
