Composition Of Suspended Particulate Matter Research Articles

Particulate and dissolved elemental loads in the Kuji River related to discharge rate

In order to investigate influences of discharge rates on fluvial transport behavior of elements in the Kuji River, Japan, suspended and dissolved phase concentrations in the river water were measured together with the water flow rates. The concentrations of suspended particulate matter (SPM) increased by two or three orders of magnitude with the water discharge, and also had seasonal variations. Adsorptive elements or heavy metal elements, which tend to form insoluble compounds, were present generally as suspended forms in the river waters, and their dissolved form concentrations tended to increase with the water discharge. On the other hand, non-adsorptive elements such as alkali and alkaline-earth elements were present as dissolved forms under a normal flow rate condition, but equivalent quantity of suspended species also occurred under a high flow condition. In this case, the dissolved form concentrations decreased with the water discharge. Characterization of SPM with analyses of chemical compositions, scanning electron microscopy (SEM) and X-ray diffractometry (XRD) indicated that clay mineral such as montmorillonite would be the main carrier material of trace and major elements during the fluvial transport in the Kuji River. Variations of contents of selected elements in SPM with the water discharge indicated that river bottom sediments, which are probably potential sources of SPM added due to high water flow rates, would be different in chemical compositions from SPM floating under a normal flow condition. Variations of chemical compositions of SPM as well as of suspended or dissolved form concentrations of elements in the river waters were formulated as a function of the water discharge rates.

Particulate matter and plankton dynamics in the Ross Sea Polynya of Terra Nova Bay during the Austral Summer 1997/98

The structure and variability of the plankton community and the distribution and composition of suspended particulate matter, were investigated in the polynya of Terra Nova Bay (western Ross Sea) during the austral summer 1997/1998, with the ultimate objective of understanding the trophic control of carbon export from the upper water column. Sampling was conducted along a transect parallel to the shore, near the retreating ice edge at the beginning of December, closer to the coast at the beginning of February, and more offshore in late February. Hydrological casts and water sampling were performed at several depths to measure total particulate matter (TPM), particulate organic carbon (POC), biogenic silica (BSi), chlorophyll a (Chl a) and phaeopigment (Phaeo) concentrations. Subsamples were taken for counting autotrophic and heterotrophic pico- and nanoplankton and to assess the abundance and composition of microphyto- and microzooplankton. Statistical analysis identified two major groups of samples: the first included the most coastal surface samples of early December, characterized by the prevalence of autotrophic nanoplankton biomass; the second included all the remaining samples and was dominated by microphytoplankton. With regard to the relation of the plankton community composition to the biogenic suspended and sinking material, we identified the succession of three distinct periods. In early December Phaeocystis dominated the plankton assemblage in the well-mixed water column, while at the retreating ice-edge a bloom of small diatoms (ND) was developing in the lens of superficial diluted water. Concentrations of biogenic particulates were generally low and confined to the uppermost layer. The very low downward fluxes, the near absence of faecal pellets and the high Chl a/Phaeo ratios suggested that the herbivorous food web was not established yet or, at least, was not working efficiently. In early February the superficial pycnocline and the increased water column stability favoured the development of the most intense bloom of the season, essentially sustained by micro-sized diatoms (MD). The shift of the autotrophic community toward this size component produced major changes in the composition of particulate matter and determined its export to depth. The particulate organic carbon (POC)/chlorophyll a (Chl a) and Chl a/Phaeo ratios more than halved, biogenic silica (BSi)/POC and BSi/Chl a strongly increased. Downward fluxes were greatly enhanced (reaching the yearly maximum) and essentially occurred via faecal pellets, underscoring the high efficiency of the herbivorous food web. In late February the deepening of the pycnocline, together with the decrease in light intensity, contributed to halting the diatom bloom. The biomass of small heterotrophs (HNF and MCZ) significantly increased relative to the previous period, favouring the shift toward a mistivorous food web (sensu [Ophelia 41 (1995) 153]) and resulting in the retention of biogenic matter in the superficial layer. Only in early February, with the increase in the size of primary producers (essentially represented by micro-sized diatoms), did the grazing food web become efficient [S. Afr. J. Mar. Sci. 12 (1992) 477], fuelling the long-lived carbon pool and enhancing export to depth (and hence carbon sequestration) via the sinking of large diatoms and high amounts of faecal pellets. The conditions predominating in the Terra Nova Bay polynya in mid-summer probably increased the efficiency of the CO 2 pump, possibly causing the Bay to act as a carbon sink.

Lipid composition of suspended particulate matter (SPM) in a southeastern blackwater stream

Suspended particulate matter (SPM) was collected seasonally for 1 yr at third- and fifth-order sites in a blackwater stream on the coastal plain in South Carolina. Fatty acids with carbon chain lengths from C 12–C 32 were the most abundant component among the lipid classes examined with total concentrations varying from 8.5 to 60.2 μg L −1. Unsaturated fatty acids predominated while significant concentrations of the even-chained saturated components C 24–C 30 derived from cuticular plant waxes were also found. Concentrations of aliphatic alcohols, with carbon chain lengths between C 16 and C 30, ranged from 0.52 to 2.73 μg L −1 and was dominated by the higher molecular weight compounds (C 22−C 30) derived primarily from cuticular plant waxes. Total hydrocarbon concentrations ranged from 0.35 to 5.66 μg L −1 and showed no discernible trends with time or consistent difference between sites. The hydrocarbon assemblage observed indicates that these components are entirely of biogenic origin with no detectable anthropogenic contribution. The ratios of unsaturated to saturated fatty acids and cuticular to noncuticular fatty acids and alcohols at both stream locations indicate that the organic detritus associated with SPM collected during November and January is of more recent origin and less processed than that collected in the spring and summer months. Lipid concentrations at the third-order site generally had higher and more variable concentrations of the lipid classes compared with the fifth-order site. The ratio of saturated to unsaturated fatty acids was higher at the third-order site indicating that the organic fraction of SPM at this site was of more recent origin and less decomposed. The ratios of cuticular to noncuticular fatty acids and alcohols support this conclusion. These results indicate an export of particulate lipids of higher carbon resource quality from upstream to lower stream reaches.

Suspended particulate matter in the Mediterranean water at the Gulf of Cadiz and off the southwest coast of the Iberian Peninsula

Abstract Suspended particulate matter (SPM) data from two surveys carried as part of the Canary Islands Azores Gibraltar Observations (CANIGO) project, in September 1997 and January 1998, are presented for the Gulf of Cadiz and the SW coast of Portugal. Analysis of total suspended mass, particulate organic to inorganic matter ratio, δ13C(PDB), and a microscopic analysis of particle composition were performed. Our objective was to quantify and characterise SPM in the water masses present in the study area, North Atlantic central water (NACW), North Atlantic deep water (NADW), and especially in the Mediterranean water (MW). MW was usually characterised by values of SPM higher than NADW but similar to NACW, and was different in terms of SPM composition: higher δ13C(PDB) values and relative abundance of mineral and biogenic particles, but lower relative abundance of particles

Spatial and Temporal Variability of Particulate Trace Metals in Port Jackson Estuary, Australia

Major elements (Al, Ca, Fe and Mn) and trace elements (Cu, Cr, Pb, Zn and Ni) in operationally defined available and total particulate phases have been determined along an axial transect of the Port Jackson Estuary during twelve surveys between 1998 and 1999. Salinity, temperature, pH, dissolved oxygen and suspended particulate material (SPM) were also measured. Temporal and spatial variability were tested by two-factor analysis of variance. Throughout the estuary Zn and Ni exhibited a uniform distribution. It is suggested that the low reactivity of these elements may be a result of the water physicochemistry, low SPM concentrations and long residence time in the Port Jackson Estuary. Anthropogenic sources of Zn and Ni are widespread in the Port Jackson catchment, and also contribute to the spatial distribution observed in the estuary. The distributions of particulate Cu and Pb are significantly affected by anthropogenic inputs, particularly, from the southern embayments in the lower estuary. It is suggested that the increase of Cu and Pb seaward is also related to sorption of these elements on Fe-Mn oxides. Mixing, however, can largely account for the distribution of Cr, which was the only element that presented significant decrease in concentration with increasing salinity. Embayments and tributaries of Port Jackson show distinctive signatures of particulate trace metals (Cu, Pb and Cr), as a result of anthropogenic activities around those embayments. The SPM composition has a significant seasonal variability (P≤0·05). During spring and summer, the particulate trace metals (Cr, Cu, Pb, Zn and Cr) and major elements (Al and Fe) concentrations are significantly lower than winter. This trend is ascribed to a dilution effect of plankton blooms on SPM composition.

Modeling the inherent optical properties of the ocean based on the detailed composition of the planktonic community

We describe an approach to modeling the ocean's inherent optical properties (IOPs) that permits extensive analyses of IOPs as the detailed composition of suspended particulate matter is varied in a controlled manner. Example simulations of the IOP model, which includes 18 planktonic components covering a size range from submicrometer viruses and heterotrophic bacteria to microplanktonic species of 30-mum cell diameter, are discussed. Input data to the model include the spectral optical cross sections on a per particle basis and the particle-number concentration for each individual component. This approach represents a significant departure from traditional IOP and bio-optical models in which the composition of seawater is described in terms of a few components only or chlorophyll concentration alone. The simulations illustrate how the separation and understanding of the effects of various types of particle present within a water body can be achieved. In an example simulation representing an oligotrophic water body with a chlorophyll a concentration of 0.18 mg m(-3), the planktonic microorganisms altogether are the dominant particulate component in the process of light absorption, but their relative contribution to light scattering is smaller than that of nonliving particles. A series of simulations of water bodies with the same chlorophyll a concentration but dominated by different phytoplankton species shows that composition of the planktonic community is an important source of optical variability in the ocean.

Composition of suspended participate matter in the Elbe estuary: Implications for biological and transportation processes

The composition and settling behaviour of suspended particulate matter (SPM) from the freshwater to the polyhaline zone of the Elbe Estuary was studied in April and July 1994. SPM was separated into three fractions of different settling velocities. The major portion of SPM (up to 92 %) was found to settle more slowly than 0.3 mm s-1 with a maximum concentration of 159 mg I-1. Special attention was given to organic content and microalgal pigments bound to suspended matter of different settling velocities. The composition of SPM concerning the total amount of organic material, and different algal pigments which can serve as indicators for various algal classes and degradation processes of the algal material, varied depending on the location within the estuary and on different settling velocities of the particles. Organic material was always highest (up to 90 % of the total) in the slow settling fraction. The distribution of algal pigments showed a different pattern: a substantial amount often was associated to fast settling particles (up to 20–30 %). The ratio of phaeopigments and chlorophyll-a was highest in the fast settling fraction of SPM. Variations in the amount of total organic material and algal pigments of different settling velocities result in a different transport behaviour of these components and their deposition within the estuary. The relevance of the results to various biological processes and to decisions concerning sediment dredging in the estuary is discussed.

Investigations on Mineralogical and Chemical Composition of Suspended Particulate Matter (SPM) in the Odra Estuary

In order to recognize lateral and seasonal variations in composition of suspended particulate matter (SPM) in the Odra Estuary, samples were taken at four sites in the period July 1996 - Jul y 1997 monthly if possible. The contents of the elements Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, P, C, S as well as Ba, Cr, Sr, V, Zn, Cu, Zr, and of the minerals illite, chlorite, smectite, kaolinite and others have been determined. The decreasing influence ofthe river Odra towards the open sea could be realized with the help of the contents ofthe minerals quartz, smectite, and of the elements Ba, Cr, K, P, Si and other. 60% of the seasonal and lateral variations can he explained by changing contents of total carbon (TC), total organic carbon (TOC), Al, Fe, Si, Ti, P, Mn, and Ba. They are mainly caused by differences in the production of organic matter, resuspension, riverine input, and redox-sensitive processes.

Relative composition of suspended particulate matter as function of size distribution and location

Relative composition of suspended particulate matter as function of size distribution and location

PIXE ANALYSIS OF SUSPENDED PARTICULATE MATTER ORIGINALLY COLLECTED FOR BETA-RAY ABSORPTION MASS MONITORING

A method of transferring suspended particulate matter (SPM) from the used filter of a beta-absorption mass monitor to a polycarbonate filter for subsequent PIXE analysis has been developed. The method allows determination of the relative elemental composition of SPM. It was demonstrated that PIXE analysis can detect S , Cl , Fe and Zn in SPM sampled over a one-hour period.

Aggregation and resuspension of suspended particulate matter at a seasonally stratified site in the southern North Sea: physical and biological controls

The physical and biological characteristics of suspended particulate matter (SPM) have been investigated at a site in the southern North Sea characterised by a seasonally stratified water column and a muddy sand bed. Significant variability in SPM concentration, composition, size and settling velocity was observed over tidal, spring/neap and seasonal time scales. Tidal currents alone are not sufficient to resuspend the bulk of the sea-bed sediment. However, sea-bed erosion does occur when wind/wave action enhances the bed shear stress during winter storms. Also, during winter and summer aggregated organic-rich material with a modal settling velocity of 0.2 mm s -1, originating from the sediment/water interface or from pelagic organic detritus, is subject to spring-tide or wind/wave resuspension. Phytoplankton production in the surface mixed layer (SML) is nutrient limited during much of the summer, but there can be sufficient light penetration to allow production at or below the thermocline. So production in the bottom mixed layer (BML) can be either light or nutrient limited, and BML nutrient levels do not gradually recover during the summer. Aggregation of phytoplankton is an important process at this site, resulting in significant modification of settling behaviour and hence dynamics of SPM. Settling velocity and particle size measurements indicate that both diatom and dinoflagellate blooms form large aggregates towards the end of their growth phase, with modal settling velocities between 2 and 5 mm s -1. Nitszchia pseudoseriata aggregates were relatively stable, remaining as viable sites for primary production over several cycles of tidal resuspension and deposition. Moreover, they efficiently ‘scavenged’ fine inorganic particles from the water column as they settled out. Tidal resuspension of these aggregates results in much higher water-column residence times than would be calculated simply from settling rate and water depth. This allows a greater proportion of remineralisation to be performed in the water column, rather than within the sea bed.

Vertical profiles of pigments, fatty acids and amino acids: Evidence for undegraded diatomaceous material sedimenting to the deep ocean in the Bellingshausen Sea, Antarctica

The organic carbon content and biochemical composition of suspended particulate material was investigated at five stations in the marginal ice zone of the Bellingshausen Sea during the austral spring of 1992. Stations, each consisting of profiles of between four and eight depths, were sampled along longitude 85°W from fast ice conditions to open water. Samples were collected using large volume in situ filtration systems. The horizontal and vertical distribution of organic carbon, fatty acids, pigments and amino acids reflected strongly the physical environment and planktonic species composition. Concentrations of total hydrolysable amino acids, total fatty acids and photosynthetic pigments all exhibited marked reductions with depth. At an open water station, significant levels of labile fatty acids (16 : 4 n−1 and 20 : 5 n−3) and the xanthophyll fucoxanthin were present at a depth of 3900 m, indicating the sedimentation of undegraded, diatom derived material into the deep ocean. Amino acid, fatty acid and pigment concentrations suggest that degradation rates of particulate material below 500–1000 m were very low. The results show that in some circumstances undegraded material of photosynthetic origin reaches the deep ocean. However, the significance and contribution of this material to the nutrition of deep water pelagic and benthic communities remains to be established. The results are discussed in terms of the transfer of biogenic material from the euphotic zone into the deep ocean and the implications for deep water ecosystems.

Sources and biochemical composition of suspended particulate material in a submarine cave with sulphur water springs

Sources, biochemical composition and nutritional value of suspended particulate material were investigated from February 1994 to February 1995 in a submarine cave (Grotta Azzurra, Capo Palinuro, southwestern Italy) with hot sulphur springs and associated mats of chemolithoautotrophic bacteria in its innermost dark part (Snow Hall). Concentrations of total suspended material (TSM), particulate inorganic material (PIM), organic carbon (POC), organic nitrogen (PON), chlorophyll a (Chl a), phaeopigments (Phaeo), carbohydrates (TCH), proteins (TPR) and lipids (TLI) were measured at four stations along an outside–inside transect, in order to address whether the quantity and quality of suspended particles varied over time with increasing distance from the entrance of the cave and estimate the relative contribution of chemosynthesis versus photosynthesis in supplying POC to cave heterotrophs. The abundance and biochemical composition of suspended material available to filter-feeders varied over time, but no significant quantitative or qualitative differences were detected along the outside–inside transect. Concentrations of TSM and of its different compounds (PIM, POC, PON, Phaeo, TCH, TPR, TLI) were homogeneous among the four stations or fluctuated without any consistent trend, with no apparent ageing and degradation of organic material in the innermost dark station. Conversely, concentrations of Chl a significantly decreased from outside to inside the cave at all sampling periods. It is suggested that suspended POC in Grotta Azzurra consists of mixed assemblages of particles coming from advection of photosynthetic material from the open sea and local inputs of carbon by sulphur-oxidizing bacteria. Based on POC/Chl a ratios, the relative contributions of chemosynthesis versus photosynthesis in supplying POC to benthic heterotrophs was estimated to be 31 and 69%, respectively.

Physicochemical processes and their effects on the composition of suspended particulate material in estuaries: Implications for monitoring and modelling

Major and trace element composition of suspended particulate matter from two contrasting estuaries has been examined over an annual cycle. The results have been combined with corresponding data for dissolved trace metals to examine partitioning behaviour of six metals (Mn, Zn, Pb, Cu, Ni, Cd). Some important processes controlling SPM composition and partitioning behaviour are identified. Processes which are common to all estuaries are identified and distinguished from those which are site specific. These raise some important considerations for those involved either in the design of monitoring programmes or in modelling projects.

A strontium isotopic investigation of the origin of suspended particulate matter (SPM) in the Murray-Darling River system, Australia

The strontium isotopic composition of suspended particulate matter (SPM) from the Murray-Darling River system (M-DRS) in eastern Australia varies significantly as a function of particle size. Colloidal matter ( < 1 μm) defines a linear trace (colloidal mixing line) on both 87Sr86Sr vs. 1/Sr mixing and 87Sr86Sr vs. 87Rb86Sr isochron diagrams indicating simple two component mixing; isotopic ratios decrease as a function of particle size (e.g., Murray River-Merbein, 87Sr86Sr = 0.7221−0.7160). This is the first time this type of mixing has been recognised in fluvial systems and highlights the influence of particle size on isotopic composition. The two components involved are detrital silicate grains (aggregates) and varying amounts of natural organic matter present as surface coatings. The proportion of natural organic matter increases from approximately 10–80% with decreasing particle size. The natural organic matter contains high concentrations of unradiogenic Sr which has been complexed from solution (e.g., Murray River-Merbein, 87Sr86Sr = 0.7164). Particulate fractions (>1 μm) are dominated by the silicate component and are isotopically heterogeneous and displaced from the colloidal mixing lines, with distinctly more radiogenic Sr (e.g., Murray River-Merbein, 87Sr86Sr = 0.7316−0.7354). The variation in the strontium isotopic composition is due to the differential weathering of minerals in the sediment source. Weathering of plagioclase produces unradiogenic Sr which dominates the colloidal and dissolved (<0.003 μm) fractions; the particulate fractions are mainly produced by the weathering of relatively radiogenic K-feldspar and mica. The Murray and Darling River systems have dramatically different ranges of 87Sr/86Sr; 0.7160–0.7316 and 0.7076–0.7114 respectively, due to differences in the composition and ages of rocks in their catchments. The total SPM (>0.003 μm) and dissolved (<0.003 μm) fractions contain much less radiogenic Sr and higher [Sr] and lower [Rb] concentrations than mean estimates of the catchment rocks. Relative to “World Average” estimates, the M-DRS has similar 87Sr86Sr and [Sr] concentration, but markedly lower [Rb] concentration and Rb/Sr.

On the trophic fate of Phaeocystis pouchetii (hariot): VI. Significance of Phaeocystis-derived mucus for vertical flux

The development and decline of a phytoplankton spring bloom dominated by the prymnesiophyte Phaeocystis pouchetii were studied in Balsfjord, northern Norway between 30 March and 27 May 1992. At a fixed station, the concentration and composition of suspended particulate matter was monitored and compared to the particulate matter collected in sediment traps at six different depths. Direct sedimentation of phytoplankton contributed a minor fraction to particle flux and was confined to a few diatom genera. No evidence was found for pronounced aggregation of Phaeocystis colonies during bloom decline or direct sedimentation of either Phaeocystis colonies or single cells. Particle flux was dominated by faecal-pellet sedimentation during most of the study period, suggesting zooplankton grazing to be a main loss factor. Despite an abrupt decrease in faecal-pellet sedimentation after the decline of the bloom, particulate-carbon sedimentation rates remained high. High post-bloom sedimentation rates were characterized by elevated C/N and C/Chl a ratios of largely amorphous sedimented material. Post-bloom sedimentation coincided with a decrease in transparent exopolymeric particles (TEP) in the surface layer, suggesting that this change resulted from aggregation and sedimentation of carbon-rich exopolymeric material accumulated in the surface layer in the course of the bloom. While organic-carbon accumulation indicates the significance of disintegration of Phaeocystis colonies, post-bloom mucilage sedimentation could be secondary pathway for the vertical flux of Phaeocystis-derived organic matter.

Nutrient and trace metal distributions over a complete semi-diurnal tidal cycle in the forth estuary, Scotland

The distribution of dissolved trace metals and nutrients has been examined during a complete 12.5 hour tidal cycle at an anchor station in the turbid industrialized Forthy estaury. The elemental composition of major (C, Al, Si, Fe, Ti, Ca and Mn) and minor (Cd, Cu, Pb, Zn and Ni) elements in the particulate phase has also been examined. Generally the mixing behaviour of dissolved components was similar to that observed during axial surveys of the estuary at high water. At the onset of the flood tide, however, resuspension of bottom sediment occurred before any increase in salinity. This resuspension was accompanied by increased concentrations of ammonia and nitrite, and is attributed to a flushing of porewaters. Further, in contrast to results from axial surveys where no clear pattern is evident, dissolved lead distributions indicate removal over the salinity gradient sampled (0–20). This is attributed to scavenging by the high concentrations of suspended particles (up to 2000 mg·dm −3) which were a feature of the site. At times of high particle loadings (ebb and flood tides) the composition of suspended particulate matter (SPM), e.g. organic carbon and C/N ratio, approached that of bulk sediment. When suspended loads were low, e.g. around high water, the resuspended contribution to SPM was low and C/N ratios approached the Redfield ratio indicative of fresh or recently degraded phytoplankton. The distribution of SPM loading during the tidal cycle controls total metal concentrations in the particulate phase. Using Ti as a geochemically unreactive reference element for aluminosilicate phases it is demonstrated that trace-metal distributions are more closely linked to those of Mn than to Fe. This implies that manganese oxyhydroxides are an important phase for the transport of trace metals. Iron oxyhydroxides are also likely to be important but high particle concentrations and the abundance of Fe make potential changes in the Fe/Ti ratio difficult to detect. Using dissolved and particulate trace metal results, partition coefficients (K d) have been calculated. For Mn the lowest K d values are associated with the oxygen minimum zone of the estuary, K d values for Zn also tend to be low in this zone. These results are linked to the dissolution of oxyhydroxide particulate phases in waters undersaturated with respect to oxygen. K d values for Cd decrease with increasing salinity; this is attributed to complexation in the dissolved phase by chloride.

The Distribution and Chemical Composition of Particles in a Macrotidal Estuary

Spatial and short-term temporal measurements of hydrographic parameters [salinity and concentration of suspended particulate matter (SPM)] and sediment characteristics (specific surface area, major and trace metals, C and N, 137 Cs and 241Am) have been undertaken in a rapidly accreting macrotidal estuary (Dee Estuary, north-east Wales). The composition of the sediment indicates a dominance of marine material in the estuary and that fine SPM is fluvial in origin, admixing in the water column with coarse, tidally suspended bed material. The time-variable composition of SPM in the upper estuary, where tidal energy converges, was tested against a particle mixing model incorporating the compositions of permanently suspended and temporarily suspended populations operationally fractionated according to settling velocities. Agreement with the model was reasonable but suggested additional processes such as selective resuspension and/or advection of particle types. The behaviour and characteristics of different sediment populations are discussed in the context of the cycling and fluxes of particle-bound constituents and sorptive removal of dissolved constituents, and a flux model for the accumulation of 137Cs in the estuary is developed.

Characteristics of airborne particles inside southern California museums

The concentrations and chemical composition of suspended particulate matter were measured in both the fine and total size modes inside and outside five southern California museums over summer and winter periods. The seasonally averaged indoor/outdoor ratios for particulate matter mass concentrations ranged from 0.16 to 0.96 for fine particles and from 0.06 to 0.53 for coarse particles, with the lower values observed for buildings with sophisticated ventilation systems which include filters for particulate matter removal. Museums with deliberate particle filtration systems showed indoor fine particle concentrations generally averaging less than 10 μg m −3. One museum with no environmental control system showed indoor fine particle concentrations averaging nearly 60 μg m −3 in winter and coarse particle concentrations in the 30–40 μg m −3 range. Analyses of indoor vs outdoor concentrations of major chemical species indicated that indoor sources of organic matter may exist at all sites, but that none of the other measured species appear to have major indoor sources at the museums studied. Significant fractions of the dark-colored fine elemental (black) carbon and soil dust particles present in outdoor air are able to penetrate to the indoor atmosphere of the museums studied, and may constitute a soiling hazard to works of art displayed in museums.

Distribution and composition of suspended particulate material in the clyde estuary and associated sea lochs

The composition of suspended particulate material (SPM) from the Clyde Estuary and the Firth of Clyde (including its sea lochs) has been examined. The concentration in SPM of particulate organic carbon (POC), Fe, Mn, Zn, Pb, Cu, Cd are reported. High POC concentrations in surface waters were associated with phytoplankton. Surface water SPM contained higher concentrations of Cd and Zn than that from deeper waters. By contrast concentrations of Fe, Mn, Pb and Cu (enriched in crustal material relative to phytoplankton) were higher in subsurface SPM. Trace metal concentrations in SPM were better correlated to Fe than to Mn. Estuarine particles were enriched in trace metals relative to other areas, the higher iron concentrations in the estuary were, however, insufficient to account for this enrichment. Seasonal variability in the trace metal composition of surface SPM is discussed. Elements enriched in crustal material show higher concentrations in winter than in spring.