Soil mobility of surface applied polyaromatic hydrocarbons in response to simulated rainfall

Polyaromatic hydrocarbons (PAHs) are emitted from a variety of sources and can accumulate on and within surface soil layers. To investigate the level of potential risk posed by surface contaminated soils, vertical soil column experiments were conducted to assess the mobility, when leached with simulated rainwater, of six selected PAHs (naphthalene, phenanthrene, fluoranthene, pyrene, benzo(e)pyrene and benzo(ghi)perylene) with contrasting hydrophobic characteristics and molecular weights/sizes. The only PAH found in the leachate within the experimental period of 26 days was naphthalene. The lack of migration of the other applied PAHs were consistent with their low mobilities within the soil columns which generally parallelled their log Koc values. Thus only 2.3% of fluoranthene, 1.8% of pyrene, 0.2% of benzo(e)pyrene and 0.4% of benzo(ghi)perylene were translocated below the surface layer. The PAH distributions in the soil columns followed decreasing power relationships with 90% reductions in the starting levels being shown to occur within a maximum average depth of 0.94 cm compared to an average starting depth of 0.5 cm. A simple predictive model identifies the extensive time periods, in excess of 10 years, required to mobilise 50% of the benzo(e)pyrene and benzo(ghi)perylene from the surface soil layer. Although this reduces to between 2 and 7 years for fluoranthene and pyrene, it is concluded that the possibility of surface applied PAHs reaching and contaminating a groundwater aquifer is unlikely

Polar and non-polar aromatic micropollutants in water (drinking-water) resources

Aromatic compounds are important contaminants that limit the intended uses of water resources. Both polar and non-polar substances, such as phenols, aromatic sulfonates, lignin-sulfonic acids, humic and fulvic substances (acids) and mono- and poly-aromatic hydrocarbons, their alkyl-substituted derivatives, respectively, are among the potential aromatic micropollutants. During the last 5 - 10 years, an analytical approach has been developed on the basis of total fluorescence measurement of the original water sample and its organic solvent (cyclohexane) extract. It has been demonstrated and verified that polar aromatic compounds fluoresce only in the original water sample, whereas non-polar (hydrophobic) compounds fluoresce in an organic solvent (e.g. cyclohexane) extract. During extraction, polar compounds remain in the water sample. This method has been used in a country-wide survey in drinking water aquifers, as well as in several environmental impact assessment studies, particularly for petroleum-related pollution. It is a very convenient method to determine the naturally occurring humic and fulvic substances in water and has proved to be an appropriate substitute of the infrared spectrophotometric method for oil pollution assessment in the environment, also having the advantage of signalling more harmful, toxic aromatic petroleum hydrocarbons.</jats:p

Environmental Consequences of the Gulf War in Kuwait: Impact on Water Resources

As a result of the Iraqi occupation and the armed conflict in Kuwait 6 to 8 million barrels of crude oil were spilled into the marine environment, and about 2 to 3 million barrels of crude oil, burnt and unburnt, were being emitted daily during about 300 days into the environment from the burning or gushing oil wells. International efforts of UN agencies and other organizations from, the region and outside started immediately to assess the extent of the environmental pollution and to mitigate the adverse effects. In addition to the public health concerns of the air pollution caused by the burning wells, long-term environmental risk should be considered as a result of the oil spill into the marine and coastal environment, and the atmospheric fall-out, e.g., acid rain and petroleum related compounds associated with airborne particulates, in the marine and terrestrial areas. Particularly serious contamination of the desert ecosystem occurred around the damaged oilfields in Kuwait. The deposited crude oil and airborne particulates in the terrestrial areas may also affect the ground-water aquifer. Air quality, marine and desert soil pollution surveys provided data for a preliminary assessment and helped the formulation of mitigation and rehabilitation programmes, however, implementation of an integrated survey programme will ensure the final impact assessment on the environment, particularly on the marine and subsurface water resources.</jats:p

Harmonisation of micropollutant monitoring in large international river: Danube

Micropollutants (heavy metals, organic compounds) play an important role in the quality characterisation of surface waters. These pollutants are usually bioresistant, persistent compounds or may undergo biotransformation, photo-oxidation, sometimes resulting in more toxic breakdown products than their parents, or can accelerate dispersion of hydrophobic compounds and mobilisation of heavy metals from the solid phase. Because of multiple introduction of these pollutants along a large, international river, and due to the sedimentation and re-suspension of the particulate matter by the river hydrodynamics, the deposition of the polluting compounds into the bottom sediment may occur far downstream of the discharge. Appropriate micropollutant sampling and monitoring in both the water column and bottom sediment are discussed. It is concluded that the higher the fine fraction in the sample, the more representative the sediment-bound pollutant characterisation. In order to achieve water and sediment quality guidelines and objectives for micropollutants the guidelines and monitoring programmes must be harmonised, including the sampling, sample preparation, analytical and data interpretation methods among the riparian countries along the Danube river.</jats:p

Monitoring of Petroleum-Related Environmental Contamination Using Fluorescence Fingerprinting

Petroleum and its refined products are considered the most complex contaminants frequently impacting the environment in significant quantities. They have heterogeneous chemical composition and alterations occur during environmental weathering. No single analytical method exists to characterize the petroleum-related environmental contamination. For monitoring, the analytical approaches include gravimetric, spectrometric and chromatographic methods having significant differences in their selectivity, sensitivity and cost-effectiveness. Recording fluorescence fingerprints of the cyclohexane extracts of the water, suspended solids, sediment or soil samples and applying appropriate statistical evaluation (e.g. by correlating the concatenated emission spectra of the fingerprints of the samples with arbitrary standards (e.g. petroleum products)), provides a powerful, cost-effective analytical tool for characterization of the type of oil pollution and detecting the most harmful aromatic components of the petroleum contaminated matrix. For monitoring purposes, the level of the contamination can be expressed as the equivalent concentration of an appropriate characteristic standard, based on the fluorescence intensities at the relevant characteristic wavelengths. These procedures are demonstrated in the monitoring of petroleum-related pollution in the water and suspended sediment in the Danube river basin</jats:p