Natural Suspended Particulate Matter Research Articles

A versatile test system to determine nanomaterial heteroagglomeration attachment efficiency

Test system to determine nanomaterial heteroagglomeration attachment efficiency for fate models and risk assessment.

Natural suspended particulate matter (SPM) versus lab-controlled particles: Comparison of the reactivity and association mode of Zn

River suspended particulate matter (SPM) plays a crucial role in the fate and behavior of pollutants such as Zn, a widespread trace metal commonly encountered in continental surface waters. SPM comprises particles and colloids and is described as complex, heterogeneous particles composed of mineral, organic and microbiological components with high surface reactivity. In this study, the surface properties of river SPM and its capacity to bind Zn were probed using electrophoretic mobility (EM) experiments, specific surface area (SSA) measurements, Zn adsorption tests and X-ray absorption spectroscopy (XAS). The external characteristics and reactivity of lab-controlled mineral phases (illite, ferrihydrite, illite-iron (hydr)oxide composite, and calcite) were investigated as for natural SPM. The electrophoretic mobility (EM) of the SPM exhibited low variations among the samples and was essentially assigned to the clay particles that dominate the mineralogical composition. Except for two samples, Zn adsorption experiments evidenced comparable adsorption capacity in relation to their different mineral and chemical compositions. Zn K-edge XAS data revealed that at low Zn loadings, the binding mode of this metal with environmental particles was controlled by its mineralogical composition. Indeed, linear combination fitting of the XAS curves, completed by shell-to-shell fitting, revealed that Zn is associated with SPM by surface complexation. The XAS results showed that for SPM samples collected in the high flow regime, Zn was mainly bound to clay minerals. In contrast, for the SPM sample collected during the low flow regime, Zn was bound not only to clay minerals but also to iron (hydr)oxides.

Fishing in troubled waters: Limited stress response to natural and synthetic microparticles in brown shrimp (Crangon crangon)

Marine invertebrates inhabiting estuaries and coastal areas are exposed to natural suspended particulate matter (SPM) like clay or diatom shells but also to anthropogenic particles like microplastics. SPM concentrations may reach 1 g per liter and more, comprising hundreds of millions of items in the size range of less than 100 μm. Suspension feeders and deposit feeders involuntarily ingest these particles along with their food. We investigated whether natural and anthropogenic microparticles at concentrations of 20 mg L−1, which correspond to natural environmental SPM concentrations in coastal marine waters, are ingested by the brown shrimp Crangon crangon and whether these particles induce an oxidative stress response in digestive gland tissue. Shrimp were exposed to clay, silica, TiO2, polyvinyl chloride (PVC), or polylactide microplastics (PLA) for 6, 12, 24, and 48 h, respectively. The activities of the anti-oxidative enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) were measured. All five particle types were ingested by the shrimp along with food. The presence of the particles in the shrimp stomach was verified by scanning electron microscopy. The activities of the anti-oxidative enzymes did not vary between animals exposed to different types of microparticles and control animals that did not receive particles. The temporal activity differed between the three enzymes. The lack of a specific biochemical response may reflect an adaptation of C. crangon to life in an environment where frequent ingestion of non-digestible microparticles is unavoidable and continuous maintenance of inducible biochemical defense would be energetically costly. Habitat characteristics as well as natural feeding habits may be important factors to consider in the interpretation of hazard and species-specific risk assessment.

Anthropogenic Reservoirs of Various Sizes Trap Most of the Sediment in the Mediterranean Maghreb Basin

The purpose of this study is to obtain a spatially explicit assessment of the impact of reservoirs on natural river sediment fluxes to the sea in the Mediterranean Maghreb Basin (MMB), a region where both mechanical erosion rates and the anthropogenic pressure on surface water resources are high. We combined modeling of riverine sediment yields (sediment fluxes divided by the drainage basin area) and water drainage intensities in a 5’ × 5’ grid point resolution (~10 km × 10 km) with a compilation of existing reservoirs in the area, and calculated sediment trapping based on average water residence time in these reservoirs. A total number of 670 reservoirs could be assembled from various sources (including digitization from Google maps), comprising large-scale, small-scale and hillside reservoirs. 450 of them could be implemented in our modeling approach. Our results confirm that natural sediment yields are clearly above the world average, with the greatest values for Morocco (506 t km−2 year−1), followed by Algeria (328 t km−2 year−1) and by Tunisia (250 t km−2 year−1). Including dams in the downstream routing of suspended sediments to the sea reduces the natural sediment flux in the entire MMB to the sea from 96 to 36 Mt km−1 year−1, which corresponds to an average sediment retention of 62%. Trapping rates are highest in the Tunisian basin part, with about 72%, followed by the Algerian (63%) and the Moroccan basin parts (55%). Small reservoirs and hillside reservoirs are quantitatively important in the interception of these sediments compared to large reservoirs. If we only considered the dams included in the widely used Global Reservoir and Dam (GRanD) database which comprises mainly large reservoirs sediment retention behind dams would account for 36% of the natural suspended particulate matter (SPM) flux to the Mediterranean Sea. Our data reveal negative correlation between sediment retention and natural erosion rates among the three Maghreb countries, which can be explained by the greater difficulties to build dams in steep terrains where natural sediment yields are high. Although the lowest sediment retention rates are found in the Moroccan part of the MMB, it is probably here where riverine sediment starvation has the greatest impacts on coastline dynamics. Understanding the impact of dams and related water infrastructures on riverine sediment dynamics is key in arid zones such as the MMB, where global warming is predicted to cause important changes in the climatic conditions and the water availability.

Enhanced bioaccumulation of pentachlorophenol in carp in the presence of multi-walled carbon nanotubes

The impact of suspended particles on the bioavailability of pollutants has long been a controversial topic. In this study, adsorption of pentachlorophenol (PCP) onto a natural suspended particulate matter (SPM) and multi-walled carbon nanotubes (MWCNTs) was studied. Facilitated transports of PCP into carp by SPM and MWCNTs were evaluated by bioaccumulation tests exposing carp (Carassius auratus red var.) to PCP-contaminated water in the presence of SPM and MWCNTs, respectively. Desorption of PCP on SPM and MWCNTs in simulated digested fluids was also investigated. The results demonstrate that MWCNTs (K F = 7.99 × 10(4)) had a significantly stronger adsorption capacity for PCP than the SPM (K F = 19.0). The presence of SPM and MWCNTs both improved PCP accumulation in the carp during the 21 days of exposure, and the 21 days PCP concentration in the carp was enhanced by 25.9 and 12.8 % than that without particles, respectively. The enhancement in bioaccumulation by MWCNTs was less than that by the SPM. Considerably more PCP was accumulated in the viscera of the fish (BCF = 519495 for SPM and 148955 for MWCNTs), and the difference in PCP concentrations between different tissues became greater with particles. PCP desorption in the simulated digestive fluids was faster than that in the background solution. Compared to MWCNTs-bound PCP, more SPM-bound PCP was desorbed, and K F of desorption for SPM was at least 4 orders of magnitude higher than that for MWCNTs, which can explain the greater enhancement in bioaccumulation in the presence of SPM. Particle-bound pollutants might pose more risk than pollutants alone.

Urban activity and mercury contamination in estuarine and marine sediments (Southern Brazil)

The distribution of mercury in sediments of the Patos Lagoon estuary and nearby coastal marine deposits has been investigated for the period 1998-2008. Polluted urban soils and coastal reclamation fills are the principal sources of high mercury concentrations for shallow estuarine sediments. The shallow sediments that form near the urban area enter the navigation canal and are transported into the ocean. The mercury concentration in sediments of the navigation canal has considerably increased since 2004, due to intense reconstruction activity in the urban area. Periodic dredging of the canal strengthens the preconditions for coastal marine sediment contamination by mercury. However, this does not occur because the resuspended dredged sediments are significantly diluted by natural suspended particulate matter.

Implications of short and long term (30 days) sorption on the desorption kinetic of trace metals (Cd, Zn, Co, Mn, Fe, Ag, Cs) associated with river suspended matter

The desorption kinetic of trace elements (Cd, Zn, Co, Mn, Fe, Ag, and Cs) associated with Loire river natural suspended particulate matter (SPM; 0.4–63 μm) was followed up on times varying from 0.5 h to 30 days, from SPM previously contaminated during 1 h, 24 h and 30 days. Long term sorption kinetics indicated that the difference between sorption occurring during the period 0–30 days (time investigated in this study) and the period 0–48 h (time often used for sorption experiments) ranges from few to 25% according to the element. Desorption kinetics show that, whatever the age of the complex formed during the sorption step, the release tends to equilibrium between complexed and dissolved elements equivalent to the equilibrium obtained for sorption after a given time. However, the time to get this equilibrium depends on the aging of the complex and on the element. All the above features indicate different types of complexes formation and strength of the binding according to the age of the complex and according to the element. Using a multi-compartmental model, simulating the transfer of metals between water and different types of particulate sites, the relationships between the parameters describing slow and rapid processes helped in explaining the “aging” effect observed.

Feeding adaptations of the pearl oysters Pinctada margaritifera and P. maxima to variations in natural particulates

The tropical pearl oysters Pinctada margaritifera (Linnaeus) and P. maxima Jameson are suspension feeders of major economic importance. P. margaritifera occurs in coral reef waters characterised by oligotrophy and low turbidity. P. maxima habitats are generally characterised by high terrigenous sediment and nutrient inputs, and productivity levels. These differences in habitat suggest that P. margaritifera will feed more successfully at low food concentrations, while P. maxima will cope with a wider range of food concentrations and more silty conditions. The effect of varying concentrations of natural suspended particulate matter (SPM) on clearance rate (CR), pseudofaeces production, absorption efficiency (abs.eff.), respired energy (RE) and excreted energy (EE) was determined for P. margaritifera and P. maxima. The resultant scope for growth (SFG) was determined and related to habitat differences between the oysters. There was no selective feeding on organic particles in either species. P. margaritifera had higher CR at low SPM concentration ( 3 µm) and P. maxima (SPM = ca 3 to 15 mg l⁻¹, size > 4 µm) may be used for selection of optimum pearl culture sites.

Feeding behaviour and metabolic efficiency contribute to growth heterosis in Pacific oysters [ Crassostrea gigas (Thunberg)

Physiological measurements were made on Pacific oysters from controlled crosses between inbred lines. Hybrid individuals were expected to perform better than inbred oysters, for a variety of traits related to feeding behaviour. The oysters were offered a diet simulating natural suspended particulate matter. By quantifying the organic and inorganic fractions of food, faeces and pseudofaeces, various aspects of feeding were elucidated. The results agreed with expectation; on average, hybrid oysters had higher rates and efficiencies of feeding and growth than inbreds. In one experiment there were significant differences between hybrids and inbreds for seventeen out of twenty cases; in another experiment hybrids performed better than inbreds for eight out of sixteen cases. In both experiments, we find significant differences between the reciprocal hybrids, though heterosis for growth is evident for all hybrids. Our experiments therefore confirmed heterosis for growth and hybrid superiority for physiological traits, independent of ration level; emphasised the complexity of these relationships amongst genotypes; and demonstrated the segregation of physiological traits in the F 2 generation.

Simultaneous determination of particulate organic carbon, nitrogen and phosphorus collected on filters, using a semi-automatic wet-oxidation method

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 180:289-295 (1999) - doi:10.3354/meps180289 Simultaneous determination of particulate organic carbon, nitrogen and phosphorus collected on filters, using a semi-automatic wet-oxidation method P. Raimbault1,*, F. Diaz1, W. Pouvesle1, B. Boudjellal2 1Laboratoire d'Océanographie et de Biogéochimie (UMR CNRS 6535), Centre d'Océanologie de Marseille, Campus de Luminy, F-13288 Marseille Cedex 09, France 2ISMAL, BP 54, Plage ouest, Sidi Fredj/Staoueli, Gouvernorat du grand Alger, Algeria *E-mail: raimbaul@com.univ-mrs.fr ABSTRACT: A wet-oxidation method is presented for determining simultaneously particulate organic carbon (POC), particulate organic nitrogen (PON) and particulate organic phosphorus (POP) collected on filters. Conversion of POC, PON and POP to inorganic products, carbon dioxide, nitrate+nitrite and soluble reactive phosphate respectively, is performed by a persulfate wet-oxidation in slight alkaline condition. After oxidation, inorganic products are dissolved in the digestion mixture and concentrations are measured automatically by colorimetry using a 3 channel Technicon AutoAnalyzer®. Concurrent comparisons were made with dry combustion at 950°C for POC and PON (CHN analysis) and with former wet-oxidation procedure for POP. Results indicated high efficiency to oxidize natural suspended particulate matter from sea- and freshwater as well as phytoplankton cultures and sinking particles collected by sediment traps. This method also exhibits good reliability and precision in comparison with former procedures and is highly suitable for routine analysis and especially appropriate for shipboard work. KEY WORDS: Wet-oxidation · Particulate matter · Carbon · Nitrogen · Phosphorus Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 180. Publication date: May 03, 1999 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1999 Inter-Research.

Influence of Natural Organic Matter on the Sorption of Biocides onto Goethite, II. Glyphosate

There has been relatively little research to date on the factors affecting the speciation, distribution and ultimate fate of organic chemicals, including biocides in natural aquatic systems. This paper is one of a series aimed at increasing the understanding of factors effecting biocide speciation in natural water systems. In this paper we report the results of experiments designed to identify the main factors affecting sorption of glyphosate by goethite which was used as a surrogate for natural suspended particulate matter (SPM). Sorption experiments were conducted to investigate the effect of pH, glyphosate concentration and the type and concentration of both the soluble and adsorbed natural organic matter (NOM) on the sorption of glyphosate onto goethite.

Determination of size and element composition distributions of complex colloids by sedimentation field-flow fractionation—inductively coupled plasma mass spectrometry

Sedimentation field-flow fractionation (SdFFF) and inductively coupled plasma mass spectrometry (ICP-MS) have been directly combined and the resulting SdFFF-ICP-MS instrument can be used to produce element based size distributions of colloidal samples. Using appropriate tracer elements the size distributions of specific components can be picked out from a complex mixture. Changes in chemical composition of mixtures as a function of particle size can be readily monitored by plotting appropriate element atomic ratio distributions. These applications have been illustrated using data obtained with samples of the clay minerals kaolinite and illite and a natural suspended particulate matter from the Darling River (Australia).

Feeding by the planktonic calanoid copepod Acartia clausi Giesbrecht on natural suspended particulate matter of varying quantity and quality

The defaecation rate of females of the calanoid copepod Acartia clausi Giesbrecht as a measure of the ingestion rate was measured in relation to quantity and quality of natural suspended particulate matter. In the April–September experiments, phytoplankton was the dominant component of suspended particulate matter and the ambient chlorophyll a concentration was high, ranging from l.11 to 23.91 μg·l −1. The defaecation rate became saturated below the ambient particle concentration and the weight-specific defaecation rate was rectilinearly fitted against particle concentration. In terms of chlorophyll a, the critical concentration for saturation of the weight-specific defaecation rate ranged from 0.616 to 1.710 μg·l −1. In the October–November experiments, the ambient chlorophyll a concentration ranged from 0.27 to 0.53 μg·l −1 and non-living particles became the dominant component. No critical concentration was observed and the slope of the line describing the relationship between particle concentration and weight-specific defaecation rate was greatly reduced in comparison with that obtained in the April–September experiments. The reduction of the slope may be due to the dominance of non-living particles.