This practice-based research study examines two questions in an effort to determine how the photographer can play a role in the promulgation of environmental activism. Firstly, I ask if certain aesthetic approaches to the documentation of industrial pollution can be regarded as antithetical to the values of environmentalism; in particular, I examine the use of the sublime and the role that beauty plays in documenting scenes of environmental despoliation. In response to this question, I describe the problems associated with establishing a counter-aesthetic position in my artistic practice, which is commensurate with environmental ethics. Secondly, I ask how photography can be used as a means of conducting environmental protest by working in solidarity with environmental scientists and activists, in the struggle for environmental remediation. In a bid to answer this question, I argue that the production and dissemination of the photobook is one method of realising the dissensual capacity of art to bring about the conditions necessary for remediation to occur. Importantly, my practice proceeds through an understanding of debates ongoing in contemporary theory. In particular, I argue that Jacques Rancière s conceptions of dissensus (Rancière, 2010: 173) and the politics of aesthetics (Rancière, 2004: 25) can be interpreted as a means of understanding how aesthetics can be used to enact a form of political praxis. Using Rancière and Murray Bookchin s concept of social ecology as a basis for my artistic practice, I claim that photography can not only make the existent reality of pollution visible, it can also initiate a form of participatory democratic subjectivity, allowing the demands of the artist to become visible too. Moreover, in the design and dissemination of the three photobooks I have created, I make a case for a collaborative model of artistic practice, which extends beyond the medium specificity of photograph, and embraces multimodality and trans-disciplinarity, as a means of situating the photograph into a broader discursive field.

Elevated arsenic content in food crops pose a serious human health risk. Apart from rice wheat being another main food crop is possibly cultivated on contaminated sites. But for wheat uptake mechanisms are not entirely understood especially with regard to nutrient fertilization and different moisture regimes taking into account heavy rainfall events due to climate change. Here we show that especially higher P-fertilization under changing redox conditions may enhance arsenic uptake. This counteracts with higher N-fertilization reducing arsenic transfer and translocation into aboveground plant parts for both higher P-fertilization and reducing soil conditions. Arsenic speciation did not change in grain but for leaves P-fertilization together with reducing conditions increased the As(V) content compared to other arsenic species. Our results indicate important dependencies of nutrient fertilization, moisture conditions and substrate type on As accumulation of wheat as one of the most important crop plants worldwide with implications for agricultural practices.

Non-thermal plasma generated in a dielectric barrier packed-bed reactor has been used for the remediation of chlorinated volatile organic compounds. Chlorinated VOCs are important air pollutant gases which affect both the environment and human health. This thesis uses non-thermal plasma generated in single and multiple packed-bed plasma reactors for the decomposition of dichloromethane (CH2Cl2, DCM) and methyl chloride (CH3Cl). The overall aim of this thesis is to optimize the removal efficiency of DCM and CH3Cl in air plasma by investigating the influence of key process parameters. This thesis starts by investigating the influence of process parameters such as oxygen concentration, initial VOC concentration, energy density, and plasma residence time and background gas on the removal efficiency of both DCM and CH3Cl. Results of these investigations showed maximum removal efficiency with the addition of 2 to 4 % oxygen to nitrogen plasma. Oxygen concentrations in excess of 4 % decreased the decomposition of chlorinated VOCs as a result of ozone and NOx formation. This was improved by adding an alkene, propylene (C3H6), to the gas stream. With propylene additives, the maximum remediation of DCM was achieved in air plasma. It is thought that adding propylene resulted in the generation of more active radicals that play an important role in the decomposition process of DCM as well as a further oxidation of NO to NO2. Results in the single bed also showed that increasing the residence time increased the removal efficiency of chlorinated VOCs in plasma. This was optimized by designing a multiple packed-bed reactor consisting of three packed-bed cells in series, giving a total residence time of 4.2 seconds in the plasma region of the reactor. This reactor was used for both the removal of DCM, and a mixture of DCM and C3H6 in a nitrogen-oxygen gas mixture. A maximum removal efficiency of about 85 % for DCM was achieved in air plasma with the use of three plasma cells and the addition of C3H6 to the gas stream. Nitrogen oxides are air pollutants which are formed as by-products during the decomposition of chlorinated VOCs in plasmas containing nitrogen and oxygen. Results illustrate that the addition of a mixture of DCM and C3H6 resulted in the formation of the lowest concentration of nitric oxide, whilst the total nitrogen oxides concentrations did not increase. A summary of the findings of this work is presented in chapter eight as well as further work. To conclude, the maximum removal efficiency of dichloromethane was achieved in air plasma with the addition of 1000 ppm of propylene and the use of three packed-bed plasma cells in series. The lowest concentration of nitric oxide was formed in this situation.

Elevated arsenic content in food crops pose a serious human health risk. Apart from rice wheat being another main food crop is possibly cultivated on contaminated sites. But for wheat uptake mechanisms are not entirely understood especially with regard to nutrient fertilization and different moisture regimes taking into account heavy rainfall events due to climate change. Here we show that especially higher P-fertilization under changing redox conditions may enhance arsenic uptake. This counteracts with higher N-fertilization reducing arsenic transfer and translocation into aboveground plant parts for both higher P-fertilization and reducing soil conditions. Arsenic speciation did not change in grain but for leaves P-fertilization together with reducing conditions increased the As(V) content compared to other arsenic species. Our results indicate important dependencies of nutrient fertilization, moisture conditions and substrate type on As accumulation of wheat as one of the most important crop plants worldwide with implications for agricultural practices.