Mark F. Fitzsimons

Characterisation and quantification of organic phosphorus and organic nitrogen components in aquatic systems: A Review

This review provides a critical assessment of knowledge regarding the determination of organic phosphorus (OP) and organic nitrogen (ON) in aquatic systems, with an emphasis on biogeochemical considerations and analytical challenges. A general background on organic phosphorus and organic nitrogen precedes a discussion of sample collection, extraction, treatment/conditioning and preconcentration of organic phosphorus/nitrogen from sediments, including suspended particulate matter, and waters, including sediment porewaters. This is followed by sections on the determination of organic phosphorus/nitrogen components. Key techniques covered for organic phosphorus components are molecular spectrometry, atomic spectrometry and enzymatic methods. For nitrogen the focus is on the measurement of total organic nitrogen concentrations by carbon hydrogen nitrogen analysis and high temperature combustion, and organic nitrogen components by gas chromatography, high-performance liquid chromatography, gel electrophoresis, mass spectrometry, nuclear magnetic resonance spectrometry, X-ray techniques and enzymatic methods. Finally future trends and needs are discussed and recommendations made.

Submarine hydrothermal brine seeps off Milos, Greece. Observations and geochemistry

A shallow hydrothermal brine seep located off the Greek island of Milos in the Aegean Sea was studied. The brine fluid outcropped as a pool of water in a seabed depression and was detected in the surrounding pore-waters of sediments colonised by the sulphur bacterium Achromatium volutans. The seep fluid was highly saline and sulphidic, depleted in Mg2+ and SO42−, but enriched over seawater in Na+, Ca2+, K+, Cl−, SiO2, reduced species and dissolved gases. The high concentrations of Na+, Ca2+ and K+ were consistent with the Milos tectonic setting. Na-K and Na-K-Ca geothermometers predicted a reservoir temperature of 300–325 °C for the most concentrated seep samples. The deep geothermal reservoir within the metamorphic basement of Milos island has already been located and studied and may represent the source of the seep fluid. Faunal diversity was lowest in seep-influenced sediments, but a sulphide-intolerant species was found in areas of the bacterial mat where salinity and temperature were much lower. Pressure-induced variations in the vertical depth of the brine interface may be occurring in the sediment.

Chemoautotrophic microbial mats in submarine caves with hydrothermal sulphidic Springs at Cape Palinuro, Italy

A bstractObservations were made on the distribution, morphology, and chemoautotrophic potential of microbial mats found in submarine caves of dolomitized limestone which contain hydrothermal sulphidic springs at Cape Palinuro, Italy. The distribution of microbial mats is closely associated with the flow of hydrothermal fluid from springs whose activity is intermittent and initiated during low tide. Fluid emitted from active springs in the Grotta Azzurra has a maximum temperature of 24.6°C and is enriched in dissolved sulfur species (H2S, S2O32−) and dissolved gases (CH4, CO2). However, it is depleted in NaCl and dissolved O2, in comparison with ambient seawater. This fluid is less dense and rises above the ambient seawater to form a visible thermocline and chemocline separating both layers in the submarine caves. Microbial mats were attached to rock surfaces immersed in fluid above the chemocline and were differentiated into brown and white forms. Brown mats were composed of trichomes (4.2 ± 0.1 μm and 20.3 ± 0.7 μm in diameter) resembling the calcareous rock-boring cyanobacterium Schizothrix and clusters (6 μm in diameter) of sarcina-like cells morphologically resembling methanogenic bacteria. White mats were composed of attached filaments resembling Beggiatoa (19.3 ± 0.5 μm, 39.0 ± 1.7 μm, and 66.9 ± 3.3 μm in diameter) and Thiothrix (4.2 ± 0.2 μm in diameter). Flexibacteria (<1 μm in diameter) were common to both mats. Beggiatoa-like filaments were morphologically similar to those attached to rocks and the byssal threads of mussels from Lucky Strike vent field on the Mid-Atlantic Ridge. Morphological comparisons were also made with typical gliding Beggiatoa from shallow seeps in Eckernförder Bucht, Baltic Sea. White mats displayed chemoautotrophic fixation of CO2 under relatively well-oxygenated laboratory conditions (maximum rate 50.2 nmol CO2/mg dry wt/h) using internal S0 or possibly S2O32− as electron donor. Photosynthesis may be limited in the Grotta Azzurra by insufficient illumination (6.3 × 10−7μ einsteins/cm2/s), with the possibility of Schizothrix living (at least in part) as a chemoheterotroph on white mats.Chemoautotrophic fixation of CO2 by white mats is proposed as a significant source of nutrition for benthic fauna in these caves, and has been estimated as contributing 50–70 μmol CO2/m2 of mat/min, as measured under laboratory conditions.

Aminopropanone as a marker for raw sewage in natural waters

Abstract Aminopropanone has been identified in raw sewage. Its presence at high concentrations (up to 60 μmol l−1) in several samples from the Mersey Estuary (UK) and Port Erin Bay (Isle of Man) is consistent with the contamination at those sites. The lifetime of the ketone is sufficiently long ( t 1 2 ca 8–10 days in raw sewage) for it to be useful as a tracer for untreated sewage.

Distributions and adsorption of the methylamines in the inter-tidal sediments of an East Anglian Estuary

Abstract Sediment cores were taken from a pristine mudflat in SE England, UK, at different stages of the tidal cycle in order to study potential sources and distributions of the methylamines (MAs). They were abundant in both the pore-waters and sediments, with trimethylamine (TMA) being most abundant (up to 4.7 μM and 4.6 μmol g −1 in the pore-waters and solid phase, respectively), followed by dimethylamine (DMA) and monomethylamine (MMA). Their pore-water concentrations were compared with salinity, as the osmotic responses of invertebrates to salinity changes have been proposed as a source of MAs, but no correlation was observed, possibly due to subsequent bacterial uptake. Solid phase MA distributions were also poorly correlated with ammonium and total nitrogen, suggesting that MAs were not being generated by organic degradation. The adsorption coefficients of the MAs were much higher than those for ammonia, and the degree of adsorption, namely TMA>DMA>MMA, was explained both by the basicity of the free compounds and the solvation behaviour of their protonated analogues. The particulate MAs contributed up to 2% to TN at depth in one core, which is enough to alter the C / N ration by one unit. Thus, while sources of the MAs in these sediments could not be clearly identified, their adsorption behaviour can be related to chemical structure and they have been shown to be a potentially important fraction of the sedimentary nitrogen budget.

Determination of volatile amines in sediment and water samples

Abstract A sensitive and reproducible method was developed for the determination of μg l −1 levels of methylamines in marine samples. The compounds are preconcentrated from water or pore-water samples by microdiffusion, then determined by gas chromatography on a packed column of untreated Chromosorb 103 (60–80 mesh), using a nitrogen—phosphorus-selective detector.

Pharmaceuticals in soils of lower income countries: Physico-chemical fate and risks from wastewater irrigation

Population growth, increasing affluence, and greater access to medicines have led to an increase in active pharmaceutical ingredients (APIs) entering sewerage networks. In areas with high wastewater reuse, residual quantities of APIs may enter soils via irrigation with treated, partially treated, or untreated wastewater and sludge. Wastewater used for irrigation is currently not included in chemical environmental risk assessments and requires further consideration in areas with high water reuse. This study critically assesses the contemporary understanding of the occurrence and fate of APIs in soils of low and lower-middle income countries (LLMIC) in order to contribute to the development of risk assessments for APIs in LLMIC. The physico-chemical properties of APIs and soils vary greatly globally, impacting on API fate, bioaccumulation and toxicity. The impact of pH, clay and organic matter on the fate of organic ionisable compounds is discussed in detail. This study highlights the occurrence and the partitioning and degradation coefficients for APIs in soil:porewater systems, API usage data in LLMICS and removal rates (where used) within sewage treatment plants as key areas where data are required in order to inform robust environmental risk assessment methodologies.

Determination of 1-aminopropan-2-one, a dissolved sewage component, in water samples

A new method for the determination of 1-aminopropan-2-one (APR) in water samples was developed. APR was synthesised as its hydrochloride and derivatized with 2,4-dinitrophenylhydrazine (DNPH) for determination by high-pressure liquid chromatography with ultraviolet detection (UV-HPLC). APR was determined in water samples at pH 12 using a gas-stripping chamber, connected to a cartridge containing DNPH. Acidified water samples were injected into the gas-stripping chamber and a solution of NaOH added to bring the solution to pH 12. APR was volatilised and stripped from solution and passed onto the cartridge under a constant stream of nitrogen gas. Gas flow rates were carefully controlled to allow maximum contact of APR with DNPH on the cartridge. When the reaction time had elapsed, the cartridge was disconnected and the derivative eluted with a fixed volume of acetonitrile and injected onto the HPLC, where the APR hydrazone was resolved isocratically with a mobile phase consisting of acetonitrile and water (60:40). The HPLC was calibrated using standard solutions of the APR hydrazone. Recoveries of APR from standard samples were 90-100% at the 10 microM level and the detection limit for the method was calculated as 18 nM. Detection of APR in urine and primary-treated sewage samples (41 nM and 1.225 microM, respectively) confirmed the applicability of the technique to analysis of environmental samples.

4.04 – The Role of Suspended Particles in Estuarine and Coastal Biogeochemistry

This chapter deals with the interactions of chemical species with suspended particulate matter (SPM), including nutrients, organic pollutants, metals, and radionuclides. The definition of SPM and its physical and chemical characteristics are introduced and followed by an evaluation of the distribution coefficient, K d . The subsequent sections focus on both quantitative evaluations of SPM as a source and sink for chemical species, and the identification of mechanisms controlling these interactions. This chapter identifies how such interactions have been incorporated into estuarine–coastal models, including equilibrium and kinetic models. The chapter concludes with priorities for future SPM research.

Processes of distribution of pharmaceuticals in surface freshwaters: implications for risk assessment

The global consumption and production of pharmaceuticals is increasing concomitantly with concern regarding their environmental fate and effects. Active pharmaceutical ingredients are mainly released into the aquatic environment through wastewater effluent discharge. Once in the environment, pharmaceuticals can undergo processes of natural attenuation, i.e. dilution, sorption, transformation, depending on physico-chemical properties of the compound, such as water solubility, lipophilicity, vapour pressure, and environmental conditions, such as pH, temperature and ionic strength. A major natural attenuation process is the sorption on dissolved organic matter, colloids, suspended solids and sediments, which in turn control pharmaceuticals distribution, residence time and persistence in aquatic systems. Here we review studies of sorption capacity of natural sorbents to pharmaceuticals. These report on the importance of several environmental and sorbent-specific properties, such as the composition, quality, and amount of the sorbent, and the environmental pH, which determines the speciation of both the sorbent and compound. The importance of accounting for distribution processes on freshwater sorbents for any determination of environmental concentrations of pharmaceuticals is apparent, while the reliability of surrogate standards for measuring dissolved organic matter (DOM) distribution is evaluated in the context of the need for robust environmental risk assessment protocols.