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A global survey examining the use of bioremediation technologies for addressing environmental pollution problems has been carried out. There were respondents from all continents (except Antarctica), though North America was comparatively over-represented. Despite a high aspiration to apply bioremediation techniques, this was not borne out in current practice. Air pollution was the lowest priority. Otherwise, a clear association was seen between the per capita income of a region and the concerns, remediation techniques and research practice adopted. For example, contamination of groundwater had higher priority in developed countries/regions. Toxic metals and aromatic hydrocarbons were the most common concern, while alkyl halides were of greater concern in North temperate (comparatively economically developed) countries than elsewhere. Only 15-35% of respondents used online databases to guide the design of their experiments, and these were largely restricted to North America and Europe, three quarters of US respondents used modelling software compared with about a third elsewhere. Consequently, while the developed economies made higher use of low-cost in situ bioremediation technologies (e.g. Monitored Natural Attenuation), their developing counterparts appeared to focus on the more expensive, sometimes ex situ, technologies. Despite the significant investment in and widespread availability of online resources, their limited use emphasizes the need to explore avenues for improved training and the development of more user-friendly resources. In this regard, this survey has produced a bioremediation research wish list to guide such developments. The data from this survey may also contribute to policy-decision making worldwide.
 

Microbial bioremediation; Phytoremediation; Xenobiotics; Bioinformatics; Mathematical modelling; Global survey
 

Contamination of ecosystems by xenobiotic compounds (including various organic petroleum hydrocarbons, pesticides and other agrochemicals, pharmaceutical products and heavy metals) causes ecological problems leading to serious environmental problems [1-5]. Attempts at remediating contaminated sites have used conventional but often costly approaches, such as ‘pump and treat’, excavation and removal, soil vapour extraction, and other chemical treatments [6]. These methods are time consuming, invasive, disruptive to natural habitats and usually result in a rearrangement of the problem [3]. Using these methods, it is estimated that the cost of reinstatement of all contaminated sites in the United States alone is approximately US$1.7 trillion [7]. Lately however, bioremediation has proven to be a safe, effective, low-cost and environmentally friendly alternative for sustainable remediation of environments contaminated by hazardous and recalcitrant pollutants [3,8-11]. Bioremediation uses biological processes and naturally occurring microbial catabolic activity to eliminate, attenuate or transform contaminants to less hazardous products such as carbon dioxide, water, inorganic salts, and microbial biomass [10,12-14].

Bioremediation generally has high public acceptance and can be carried out in various environmental media for a wide variety of organic and inorganic compounds [14]. However, bioremediation research and practice are currently still hampered by an incomplete understanding of the genetics and genome-level characteristics of the organisms used, the metabolic pathways involved, and their kinetics. The result of this is an inability to model and predict the behaviour of these processes, and hence a difficulty in developing natural bioremediation processes in the field [15-20].

Bioremediation techniques can take place in situ and ex situ, and have been widely characterized [3,14,21-23]. While the former may lead to minimal disruption of sites and elimination of handling costs, they usually require longer periods of treatment and extended monitoring. They can also be constrained by geological, hydro-geological and other environmental factors, resulting in a low efficiency of contaminant removal [3,15,23]. The latter (such as land farming, biopiling, composting and bioreactor treatment) involve the removal of materials by excavation, pumping or dredging, which allows greater process control though there will be some disruption to the site. They are also more thorough and enable environmental conditions of contaminated material to be easily modified and monitored, leading to greater efficiency of treatment. However excavation and transport of materials add significantly to remediation costs, leading to a preference for in situ techniques [14,15,21].

There have been various reports of biodegradation and bioremediation activities utilizing particular bacteria or plant species, with various degrees of success [16,17,20,24,25]. However, no investigations have been found relating to trends and possible drivers in the global use of these techniques. Kinya and Kimberly [18] surveyed the extent to which remediation firms and research centers have implemented strategies for clean-up of soils and groundwater, comparing clean-up costs, and related opinions on the use of non-indigenous microorganisms for bioremediation. However the survey, which was quite detailed, focused on one country and one compound-the USA and Tricholoroethylene (TCE) respectively.

Therefore, information on the following is not well known: (1) the demography of the relative acceptance and global use of bioremediation, (2) the factors driving such usage, (3) the barriers limiting its implementation, and (4) the extent of application of current biotechnological advances within the sector. Lekakis [26] used Greece as a case study to explore the relationship between economic indices (Gross Domestic Product, and per capita income) and public spending on Research and Development (R&D) for environmental protection and conservation. Summersgill [27] provided information on costs and market conditions and use of remediation technologies across Europe. The study which covered a three-year period (2001-2003), elaborated on the prominence of particular remediation technologies in member states and the reasons behind such prominence. It highlighted market changes that have occurred during that period in five European countries, and showed that the primary driving force was cost. Jalal and Rogers [28] carried out a similar study among Asian countries and showed marked variability between rich and poorer countries in the perception and approach to remediation issues. These reflected their relative abilities to invest in R & D for novel techniques such as bioremediation. Rivett, Petts et al. [29] also observed marked contrasts in levels of importance accorded to process-based remediation techniques versus physical methods like land filling. There was a lack of centralized information on remediation activity, even in some first-world countries, and differences in levels of funding for the development and provision of remediation information. Thus, economic barriers may limit certain countries’ access to the growing body of information on degradation of xenobiotics by micro-organisms.

Available historical data on the usage of bioremediation technologies for decontamination of polluted sites are somewhat uninspiring. The UK Environment Agency [30] reported that of the 391 contaminated land sites addressed during the 2000-2007 period, in situ bioremediation was used on only 4. Ex situ bioremediation was proposed, but not actually used, on only 2 sites. Phytoremediation - the use of plants for land remediation - was not even mentioned. Relatively higher figures have been reported for the United States. According to the US-EPA [31], of the 997 source-control-treatment projects carried out during the 1982-2005 period, 240 were classified as ‘innovative technologies’, of which there were 60 ex situ and 53 in situ bioremediation projects-a small percentage (~12%) overall. These two reports indicate that the contribution of bioremediation to environmental site clean-up has been very small. Information on researchers’ preferences has also not been found.

Molecular tools, other ‘omics’ technologies, and decision-support software for selection of ‘gentle’ remediation approaches have been documented [8,19,32-35]. A number of software tools for modelling environmental perturbations have also been developed [36-38]. However, information on the extent of use of such tools and technologies is restricted to certain countries. Therefore, in order to get a coherent picture of the status of bioremediation activities, a global survey was conducted to investigate drivers and barriers to the use of bioremediation, evaluate global differences in priority areas and identify specific needs of the bioremediation sector.
 

A number of survey methods exist, each with their own pros and cons. These include postal/email questionnaires, face-to-face interviews, focus groups, telephone interviews, and internet/web-based surveys [39,40]. The online web-form approach was adopted in this instance to take advantage of the reach, flexibility and popularity of the World Wide Web, including the possibility of reaching a geographically dispersed audience, receiving responses in real time, enhanced convenience for responders, automated data collection and processing, and the mitigation of costs that would otherwise be incurred in travel, printing and posting of paper questionnaires.

The survey targeted individuals involved in bioremediation, and actively working within Multinational Companies, Government Agencies, Academia, Not-for-Profit Organisations and Non-Governmental Organisations, Agriculturists and ‘Other’ research groups, to whom emails containing links to the survey web-form were sent. The mailing list used for the campaign was generated using ‘Google’ searches with the terms ‘bioremediation’, ‘biodegradation’, ‘biocatalysis’, ‘environmental biotechnology’, ‘environmental remediation’, ‘environment+conference’ and ‘environmental contamination’, with specific attempts made to reach websites of bioremediation conferences, especially the Battelle’s 6^th International Conference on remediation of chlorinated and recalcitrant compounds held in Monterey California. The contact email addresses within these websites were programmatically identified and obtained using Perl [41] scripts, available from the author. No geographical restrictions to its distribution were imposed. On inspection the list showed a good mix of potential respondents from all the continents. For simplicity the survey form consisted of a single web page at .
 

Survey Content

Survey Schedule and Response

Contaminated media

Major Contaminants of concern

Preferred vs. Actual treatments methods

Identification of microorganisms used for remediation

Use of information resources and modelling software for guidance

Application of bioremediation techniques

Phyto-remediation issues

Stated Barriers to effective development

This global survey has examined the use of bioremediation technologies for addressing environmental problems. Rather than a detailed focus on any particular compound or technology, its intent was to obtain a wide picture of the current situation in the bioremediation research space. The response level was sufficiently high and provides background information to prioritize research and development work within the sector. Several conclusions are highlighted. Respondents showed a preference for environmentally friendly remediating methods even though current practice appears to be the opposite. This was thought to point to an information gap resulting in incomplete understanding of relevant bioremediation mechanisms and difficulty in monitoring and controlling bioremediation projects in the field.

Although remediation of contaminated areas is a common international concern, the context, awareness and approach taken to address the problem have been found to be country specific. This agrees with the findings of Rivett et al. [29], which indicate that the factors driving the use of bioremediation include economics/cost considerations, relative perceptions or ignorance of the extent of contamination, country-specific policies and bio-safety legislation, and stronger focus on an environmental medium such as soil at the expense of others. They also observed a marked contrast in importance accorded process-based remediation versus physical methods like land filling, and the lack of centralized information on remediation activity. There were also differences in levels of funding support for the development of and provision of remediation information.

The relative importance attached to particular contaminants and contaminated media was found to vary in different parts of the world, with the developed nations being able to deal with apparently hidden but important pollution issues. This might be connected to the availability of more sophisticated monitoring systems in place and a stronger appreciation of the impact on health and well-being. The developed economies-North America and Europe-expressed concern and tackled issues that are not immediately perceptible but with long term benefit (for example pollution of groundwater resources). Their developing counterparts, however, appeared to focus on the more visible surface media, like soils and surface water bodies. If this status quo remains, African, South American and Asian countries could be at long term risk of major environmental catastrophes, arising from unmitigated pollution of groundwater resources.

One useful point emanating from this analysis is that researchers appear to benefit from using database and modeling resources. The observed limited use of available information resources could be due to the resources not being user-friendly. There is therefore a further role here for bioinformatics to support bioremediation research, perhaps initially with a literature-focused resource. Table 4 provides a prioritized list to help focus any such developments.

The study has established that the use of low-cost in situ bioremediation technologies is higher in the developed economies (North America and Europe) while the relatively more expensive, sometimes ex situ, technologies are used more in the developing regions. The possible implications of this have been discussed. When the findings of this survey are related to the GDP per capita of the continents (see Table 5) there appears to be a connection between development/wealth and bioremediation practice. This finding approximates to the relationship described in Environmental Kuznets Curves (EKC), a concept propounded by Grossman and Krueger [79,80].

EKCs describe the relationship between environmental quality and the level of per capita GDP. It hypothesizes that the relationship has an inverted ‘U’ shape (see Figure 8), where increases in per capita income gradually increase environmental deterioration/decay, until a turning point where it begins to steadily decrease [81]. So such GDP growth not only creates the conditions for environmental improvement by raising demands for improved environmental quality, it also makes resources available for supplying the desired improvement [82]. The concept has been a subject of numerous reviews and critical analysis [81,83,84]. It has been found to hold true for some indices of environmental quality (like air quality/emissions, Biological Oxygen Demand and Chemical Oxygen Demand), and not for others (including carbon emissions and deforestation). It has also been argued that favorable policy and institutional interventions are also necessary for sustained environmental improvement. The EKC discourse however agrees on the existence of some relationship between nations’ wealth status and their environmental-pollution experience, a position supported by this survey. These results complement available information and can contribute to bioremediation policy decisions worldwide.
 

The study was funded by the Petroleum Technology Development Fund (PTDF), of the Federal Republic of Nigeria. Thomas Gallagher, Senior Scientist at Lonza Biologics Plc, Great Abington, UK, advised in the development of some web server scripts.
 

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