Product Description

Bioremediation is a process applied to restore contaminated sites using biological tools. The success or failure of this process usually depends on an understanding of the biotechnological process as
well as the strengths and weaknesses of the ecotoxicological tools used for its evaluation.

This useful book offers a unique treatment of the subject, linking soil ecotoxicity tests, bioremediation and environmental risk assessment. It also, describes the inter-relationships between the laboratory and field ecotoxicologist, the biotechnology consultant and different international environmental regulatory agencies and explains how they seek to achieve a successful evaluation of contaminated site restoration.

Product Details

• Amazon Sales Rank: #493760 in Books
• Published on: 2002-02-28
• Original language: English
• Dimensions: .2 pounds
• Binding: Hardcover
• 490 pages

Review
"Presents scientific and theoretical approaches to the evaluation and restoration of contaminated sites." (SciTech Book News, Vol. 26, No. 2, June 2002)

"...essential to the libraries of...professionals as they provide real world analysis of the issues and applications to allow them to perform their jobs better." (Chemical Health and Safety, Vol. 10, No. 1, January/February 2003)

"...The book will be essential reading for all those involved in land or water reclamation, regulators, environmental consultants and industrial ecotoxicologists. (Int Jnl of Environmental Analysitcal Chemistry, Vol.82, No.10, 2003)

"...It is a clearly written and authoritative book that will be of great value to students , regulators and consultants alike." (Journal of Applied Toxicology, March-April 2003)

"I fully agree with the comments made by the editors?that sponsored this book: 'This is a book that everyone involved in development of contaminated sites should read...'" (Journal of Hazardous Materials, 2003)

From the Back Cover
Scientific evaluation of the restoration of contaminated sites represents a major challenge to the field of environmental risk assessment. The success or failure of contaminated site restoration often depends on a good understanding of the biological processes, as well as the strengths and weaknesses of the ecotoxicological tools used for its evaluation.

This book assesses the current approaches, using case studies to illustrate key points. It describes the inter-relationship between the laboratory and field ecotoxicologist, the contaminated site risk assessor and various international environmental regulatory agencies. This will improve communications amongst these groups, leading to better evaluation of contaminated site restoration.

This book will be essential reading for all those involved in land or water reclamation: regulators, environmental consultants and industrial eco-toxicologists. It will also be an excellent reference source for graduates and postgraduates studying bioremediation or environmental risk assessment.

Excerpt
Introduction

Agnes Y. Renoux and Geoffrey I. Sunahara
Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada

BACKGROUND
The accumulation of pollutants in soil is well known, and its re-discovery was relatively recent (i.e., within the last three decades). Ratcliffe (1967) was the first to establish the link among the land application of the pesticide DDT, the reduced population of sparrow hawk (Accipiter nisus) and peregrine falcon (Falco peregrinus), and eggshell thinning. As evidenced by these studies, it is possible to resolve that the presence of a chemical in the soil may be associated with a hazardous effect. However, this correlation is still an important challenge to ecotoxicologists, especially if one wishes to predict the risk to potential biological receptors, including humans, at a specific contaminated site. To understand why the use of toxicological tools has become a key element in the analysis of contaminated sites, it is necessary to examine the accumulation of pollutants in soil, their bioavailability and pathways for organism exposure.

Accumulation Of Pollutants At Contaminated Sites
Because of its high retention capacity, soil is very vulnerable to contaminant accumulation. Organic or inorganic contamination may stem from an accidental (overflow) or deliberate spill, or from a medium to long-term accumulation, such as that following agricultural land application, atmospheric deposit and groundwater flow (Sheppard et al. 1992). As a result, there is a high spatial heterogeneity in the contaminant distribution. Furthermore, the variability in soil composition associated with numerous physico-chemical properties can affect the chemical form in which contaminants appear. Chemically, contaminants could be found in soils as distinct particles, solutes in interstitial water, volatilized in air, or adsorbed to mineral and organic particles (Eijsackers 1994).

Bioavailability
Soil contaminant concentrations (external dose) provide little information on their bioavailability; that is, the contaminant fraction passively or actively transferred from soil (external dose) to a biological receptor (internal dose) where it can be transformed, accumulated and/or induce a response or undesired health effect (biologically effective dose). Water-soluble forms of contaminants are known to be the most bioavailable. The main route of uptake of hydrophobic contaminants is via soil pore-water for terrestrial invertebrates (BeWold et al. 1996) and for plants (van Gestel et al. 1996). Studies have shown that the toxicity of organic compounds in soil could be determined by using their concentrations in the interstitial water, as predicted by the use of adsorption coefficients (van Gestel et al. 199 1, Hulzebos et al. 1993). The organic matter, by strongly influencing the sorption of a compound, is the most important factor for controlling the bioavailability (Belfroid et al. 1996, van Gestel et al. 1996).

The effect of aging on bioavailability is controversial. As they persist or age in soil, organic compounds may become less bioavailable in short-term experiments (Alexander 2000). This sequestration is believed to be reversible, however, at a slow rate of mass transfer from the solid state to the organisms (Baveye and Bladon 1999, jagger et at 2000). This can be the result of a slow microbial release (Gunkel et al. 1993, Scheunert et al. 1995). Moreover, seemingly non-mobile contaminants linked with solid particles can also act as toxicants, simply by ingestion of the contaminated particles (Landnini and Robbins 1990, Belfrold et al. 1996, Forbes et al. 1998). A more detailed description of the bioavailability for organic and inorganic compounds is found in Chapter 2 of this book. The factors influencing bioavailability are discussed, and recommendations are given for the handling of samples and the experimental assessment of toxicity and bioavailability.

Exposure Pathways
Organisms may be exposed to soil pollutants through two different pathways: (a) direct contact with the soil (soil ingestion, contact, or inhalation); (b) after transfer of contaminants from the soil compartment to another environmental compartment such as groundwater or air. Its chemical nature and interaction with the soil constituents (mobility) influence the fate of a contaminant. Exposed organisms can also affect previously non-exposed organisms through ecological linkages such as symbiotic association, food chain transfer, etc. Thus, the impact of a contaminated soil on its environment is multi-factorial.

LIMITATIONS OF CHEMICAL ASSESSMENT
Chemical analyses are systematically used to characterize a site or to demonstrate treatment efficiency. However, the complexity of the interactions between the pollutants, the soil constituents and the biological receptors dramatically complicates the interpretation of these chemical evaluations. Consequently, the chemical concentrations cannot systematically predict the toxicity of a specific chemical.

As explained earlier in this chapter, the degree of bioavailability of contaminants in soil can extensively modify a toxic response. As a result, the sole use of chemical data to characterize the ecotoxicological hazard and the risk associated with a contaminated site is extremely limiting, and perhaps dangerous in some cases. In addition, chemical interactions may occur as a result of a multiple contamination. Many studies have shown that the co-presence of contaminants can lead, in a non-predictable manner, to a synergistic, antagonistic or additive interaction (Hass et al. 1981, Donnelly et al. 1988, Davol et al. 1989, Donnelly et al. 1990). The appearance of toxicologically unknown metabolites is another limitation to the use of chemical analyses. Physico-chemical and microbiological processes can lead to the reduction or elimination of the compound(s) of concern (mineralization) or to the production of by-products or persistent metabolises. The toxicity of these tnetabolites is often neglected. The degradation or detoxification by-products are sometimes more toxic than the compound of concern (Alexander 1981, Donnelly et al. 1987). This effect, called activa- tion, can be illustrated with the soil microbial epoxidation of aldrine into dieldrine, a product which is not only more toxic than its parent compound, but also more persistent in the environment (Lichtenstein and Schulz 1960).

THE USE OF TOXICOLOGICAL TOOLS IN ASSESSING THE IMPACT OF CONTAMINANTS
Ecotoxicological assessment (also called environmental hazard assessment) is carried out through biological, toxicological and/or ecological analyses to quantify any injury, damage or disturbance caused by a source of contamination. These data are necessary for thorough and accurate ecological risk analysis or for environmental site