Sediment porewater extraction and analysis combining filter tube samplers and capillary electrophoresis

Careful extraction and analysis of porewater from sediment cores are critical for the investigation of small-scale biogeochemical processes. Firstly, small sample volumes and high spatial resolution are required. Secondly, several chemical species in the anaerobic porewater are sensitive to oxidation when brought in contact with ambient air. Here we present the combination of a special sampling technique and an analytical method for the porewater extraction of a varved sediment core from Lake Baldegg in central Switzerland, using MicroRhizon samplers and a portable capillary electrophoresis (CE) instrument. MicroRhizon filter tubes of 1 mm diameter and 20 mm length are suitable for fast retrieval of particle-free porewater samples directly from the sediment core. Since the time-span between sampling and analysis is less than 20 seconds, oxygen-sensitive Fe(II) can be analyzed in one go together with Na+, K+, Ca2+, Mg2+, NH4+, and Mn(II) without splitting, acidification or dilution of the sample. The major inorganic cations and anions of the sediment porewater can be determined in less than 15 minutes. Detection limits are in the sub-micromolar concentration range. The capillary electrophoresis instrument used in this study requires sample volumes of only 20 mu L. These remarkable small sample volumes allow the minimization of disturbance of the sediment cores and a high spatial resolution of the sediment profile, even in sediments with low water content. The equipment is inexpensive, easy to handle, fully portable and therefore suitable for environmental on-site applications

Environmental Pollution and Restoration: A Role for Bioremediation

With greater understanding of microbial diversity and the development of bioengineering, bioremediation is taking its place as a cost-effective technique in integrated environmental restoration efforts. The major reasons for the control of water and soil pollution and the consideration of bioremediation are first and foremost, public health concerns; second, environmental conservation; and finally, the cost of decontamination. A major aim of bioremediation, or any other remediation technology, must be the reduction of toxicity associated with the environmental contaminant, that is, the abatement of environmental impact. Bioremediation solutions can be used to reduce the impacts of environmental persistence of contaminants and thus to alleviate problems associated with chronic toxicity. The broadest classification of environmental pollutants is into two categories: organic and inorganic. Quantitatively, the organic pollutants of most concern are the hydrocarbons in their various forms. The most common are petroleum hydrocarbons, chlorinated solvents, surfactants, biocides, and a host of other compounds specific to particular industries, e.g., nitroaromatics from munitions. Fortunately, many of these pollutants are biodegradable by microorganisms in soils and waters. The biodegradability of environmental pollutants, and hence the degree of persistence of contaminants in natural environments, is influenced by various factors, most important of which are the chemical structure of the contaminant, the presence of a viable microbial population able to degrade the contaminant(s), and environmental conditions suitable for microbial biodegradative activities