Biodegradation and Bioremediation – Poisoning, Toxicology&Environmental Health Example

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"Biodegradation and Bioremediation" is an exceptional example of a paper on poisoning, toxicology, and environmental health. The first factor limiting bioremediation in groundwater is the unavailability of adequate sources of energy. According to Boopathy, the capability and accessibility of reduced organic resources to function as sources of energy are one of the chief variables affecting the activity of microorganisms and bioremediation of contaminated groundwater at large (2000, p. 64). Therefore, the overall oxidation state of carbon in the material will determine the essential energy needed by the microorganisms. Generally, greater oxidation will usually result in lesser energy levels hence resulting to a lower energetic inducement for the microorganism to undergo degradation.

The effect of every degradation progression is dependent on microbiological factors such as biomass composition, enzymatic activities, and population diversities found in groundwater. Besides, the process also depends on substrate factors such as molecular structures and physic-chemical characteristics. In addition, environmental factors such as pH levels, moisture levels and temperature among others.   Bioavailability is another major challenge affecting bioremediation. Bioavailability refers to the degree at which bacterial cells can convert impurities and wastes in contaminated groundwater during the bioremediation process.

Bioremediation, therefore, is dependent on the rate of impurity uptake, breakdown, mass transfer and metabolic rate. However, it is worth noting that an amplified bacterial conversion rate does not necessarily lead to greater biotransformation rates when the mass transfer is a restrictive factor (Boopathy, 2000, p. 65). This is usually the prevalent case amongst areas with contaminated groundwater. For instance, biodegradation did not occur in aquifers with contaminated explosives even after a long period of time. The bioavailability of a pollutant depends upon biological processes such as diffusion, desorption and dissolution.

Reduced bioavailability of pollutants in the soil can be as a result of slow mass transferal to the biodegrading microorganisms. Bioactivity and biochemistry are other vital challenges that have an effect on bioremediation. Bioactivity is a term used to show the operational state of bacteriological or micro-organic processes. According to Lapworth et al. , improving bioactivity increases the process of biodegradation (2012, p. 292). For instance, when bioremediation is set to meet a specified minimum rate, one can adjust the prevailing conditions in order to alter the biodegradation rate which will in turn configure and control bioremediation.

Naturally, the capacity of microorganisms to transfer pollutants to molecules, regardless of their simplicity or complexity, is relatively unlikely. This challenge can be overseen through various biochemical activities which can be controlled in an in situ operation in which one can regulate and improve the conditions in order to achieve optimal results. Select one of the emerging contaminants listed in Lapworth et al. as a topic for the rest of the assignment (be sure it is not something we talked about in class).

Describe specific tests, experiments, and approaches a team of scientists/engineers could use to determine whether this compound could be removed from groundwater by bioremediation (in situ or ex situ).   One of the emerging contaminants highlighted by Lapworth et al. 2012 is veterinary antibiotics. The ever increasing human population has forced milk and meat industry to skyrocket. This rise has caused a sharp increase in the use of veterinary antibiotics as animal products industry seeks to achieve the highly needed efficiency and profits (Gurpreet, & Jagdev, 2011).

However, it is unfortunate that veterinary antibiotics have become an important cause of groundwater pollution especially considering that most animal farming occurs in highlands where water catchment is prominent. Veterinary products are likely to be recycled within water systems because of groundwater in high altitude areas where farming comprises a significant amount of water tapped for human consumption. One of the best approaches a group of scientists could use to determine the number of veterinary antibiotics in groundwater is the use of ‘ polar organic chemical integrative sampler’ (POCIS) to collect a wide array of samples in groundwater suspected to contain veterinary antibiotics.

The primary advantage of POCIS is that it provides in situ sample collection of samples for further analysis (Richardson, 2007). Considering that water systems in high altitude areas combine to form aquifers or rivers, this method of sample collection proves to be handy in these areas. It is important to note that the POCIS method of sample collection is perfectly suitable for water systems containing a relatively low amount of water contaminants as we would expect for veterinary products organic compounds. After sample collection using POCIS, researchers would then use ‘ Two-dimensional chromatography’ (2DC) system to analyze the collected samples (Richardson, 2007).

One of the primary advantages of 2DC is the possibility of separating different organic compounds in sampled groundwater. Unlike the traditional one-dimensional chromatography, 2DC provides more consistent and accurate results by promoting compounds separation and providing sharp conspicuous peaks for each element (Richardson, 2007). This is an important milestone for researchers because of the complex and multivariate nature of contaminants present in groundwater contaminated with veterinary products. Interestingly, cow-dung and other animal excrements contain approximately 60 different kinds of bacteria and over 100 protozoa and yeasts as well (Gurpreet, & Jagdev, 2011).

Therefore, animal excrements provide a rich and affordable means of bioremediation especially for veterinary and other multivariate compound contaminants in groundwater through bio-augmentation. The best way to identify the microorganisms in an aquifer responsible for the biodegradation of veterinary products is to do a comprehensive study of different aquifer conditions using controlled experiments. For instance, sampling can be done at different aquifers where different animals are bred as well as where no animals are bred.

Although this kind of experiment may not provide a specific microorganism- compound relationship, it is likely to provide a strong correlation between correct use of animal excrements and success of bio-augmentation in treating veterinary products contamination in groundwater. Most veterinary products are most likely to act as electron acceptors with animal excrements acting as electron donors. This comes from the fact that most of the micro-organisms are anaerobic. However, an important factor worth considering is that animal excrements especially cow-dung contains hundreds of micro-organisms which can act both as electron donors and electron acceptors.

With most veterinary products being manufactured as water-soluble compounds (Gurpreet, & Jagdev, 2011), it can safely be assumed that a large proportion of the veterinary compounds contaminants found in groundwater are water-soluble. The solubility of such compounds in groundwater actually makes it more amenable to biodegradation especially when animal excrements are used for bioremediation. Finally, provide a short paragraph outlining your professional opinion about the suitability of biodegradation/bioremediation for removal of emerging contaminants from groundwater.   In my opinion, there is a dire need to improve the rate at which modern society reacts to groundwater contamination.

Bioremediation far remains as the most efficient and cost-effective approach to controlling emerging contaminants. Although some emerging contaminants such as mining contaminants may require a specific approach, a large proportion requires the use of common methods of bioremediation. For instance, the use of animal excrements such as cow-dung provides an easy and cheap source of bioremediation if used properly. Such a bioremediation process can actually be employed in virtually all areas even where animal farming is not done.

Additionally, the use of animal excrements also boosts other methods of bioremediation such as phytoremediation.  

References

Boopathy, R. (2000). Factors limiting bioremediation technologies. Bio-resource Technology. Pg. 63-67.

Gurpreet, K, & Jagdev, K. (2011).“Bioremediation of Pharmaceuticals, Pesticides, and Petrochemicals with Gomeya/Cow Dung,” ISRN Pharmacology, vol. 2011, doi:10.5402/2011/362459

Lapworth, D., Baran, N., Stuart, E., & Ward, S. (2012). Emerging organic contaminants in groundwater: A review of sources, fate and occurrence. Pg. 287-303.

Richardson, S. (2007).Water Analysis: Emerging Contaminants and Current Issues. Anal. Chem. 79, 4295-4324

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