Suspended Particulate Matter Samples Research Articles

Suspended Sediments Quality Assessment in a Coastal River: Identification of Potentially Toxic Elements.

In coastal rivers with various human and damming activities (reservoir), the cycle and biogeochemistry of environmental pollutants in river systems has been modified. A total of 42 suspended particulate matter (SPM) samples were obtained in Jiulongjiang River, southeast China to investigate the concentration, sources, behavior, and risks of nine potentially toxic elements (PTEs) in SPM. The results of metals concentration showed relatively large variation, major for Mn and minor for Co; Mn > Zn > V > Pb > Cr > Ni > Cu > Cd > Co. Multi-index evaluation reflected that most of the PTEs are minor enrichment/moderately polluted. The Cd is defined as extremely severe enrichment/polluted level, and the Pb and Zn as minor enrichment/moderately polluted levels. Among the selected PTEs, Cd and Zn are identified as the main toxic factors of SPM with a contribution of 57 ± 18% and 14 ± 7% to the total toxic risk. The sources identification suggested that human inputs may be the primary potential source of Cd, Zn, Pb, and Co, whereas natural sources (e.g., rock weathering) are likely to be responsible for Cu, Cr, V, and Ni. In contrast, the data suggested that Mn may be attributed to both natural and anthropogenic inputs. The PTEs among dissolved, suspended, and sediment phases reflected the transportation behavior and different potential risk levels. Overall, the PTE geochemistry of river SPM can act as a good indicator of the driving mechanism of PTEs’ accumulation and provide a powerful support for controlling riverine PTEs-related pollution in coastal regions.

Biotic and abiotic degradation of suspended particulate lipids along a transect in the Chukchi Sea

Lipids and their degradation products were investigated in samples of suspended particulate matter (SPM) collected in summer 2015 from surface waters of a South-North transect (ca. 65–81°N) of the Chukchi Sea. This material appeared to be composed mainly of diatoms (dominated by Thalassiosirales) and copepod faecal pellet debris. The high solar irradiances measured in the surface waters (up to 500 W m−2) favour chlorophyll (sensitizer) photobleaching at the expense of Type II photosensitized oxidation of unsaturated lipid components of phyto- and zooplankton (photodynamic effect). The weak photoreactivity of wax esters of herbivorous zooplankton in these SPM samples contrasts with previous observations of strong photooxidation of these compounds in sinking particles, which suggests that the photodynamic effect should be favoured in large faecal pellets of herbivorous copepods sinking quickly in weakly irradiated zones. Autoxidation (free radical induced oxidation) processes operating in all oxic environments appeared to be particularly efficient in faecal pellets of omnivorous and carnivorous zooplankton and limited in those of herbivorous origin. These differences were attributed to the consumption of algal antioxidants (such as mycosporine-like amino acids and carotenoids) during the diet of omnivorous and carnivorous copepods, favouring the involvement of free radical oxidation processes.

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.

Spatiotemporal estimation of heavy metals pollution in the Mediterranean Sea from Volturno River, southern Italy: distribution, risk assessment and loads

ABSTRACT With the aim of assess the pollutant load from the Volturno River into the Mediterranean Sea, the amount of some heavy metals (As, Hg, Cd, Cr, Cu, Ni, Pb and Zn) was determined in water dissolved phase (DP), suspended particulate matter (SPM) and sediment samples. Total heavy metal concentrations were in the range 0.20–65.67 μg L−1 (mean value of 12.95 μg L−1) for DP, 1.37–601.77 μg L−1 (mean value of 105.39 μg L−1) for SPM and 14.62–157.33 mg kg−1 (mean value of 55.24 mg kg−1) for sediments. The total heavy metals input are evaluated in about 620.39 kg year−1, suggesting that the river could be an important source of heavy metals in the Tyrrhenian Sea. The ecological risk characterisation was assessed based on the National Water Quality Criteria, by comparison with criterion concentration for chronic and acute toxicity (CCC and CMC), and sediment quality guidelines. Hg and Cd showed higher values than CMC and CCC for most water samples. The Index of Geoaccumulation (I geo), Contamination Factor, Contamination degree, Pollution Load Index (PLI) and Potential Ecological Risk Index were evaluated. According to I geo and PLI, the Volturno River was uncontaminated or moderately polluted by heavy metals.

Improved protocols for large-volume injection and liquid chromatography–mass spectrometry analyses enable determination of various glycerol dialkyl glycerol tetraethers in a small amount of sediment and suspended particulate matter

Glycerol dialkyl glycerol tetraethers (GDGTs) have received considerable attention because they are useful indicators for paleoenvironment, organic matter source, and microbial community. In this study, a new simple method was developed for the analysis of GDGTs by using direct large-volume injection (LVI)–liquid chromatography (LC)–atmospheric pressure chemical ionization–mass spectrometry (APCI–MS) to reduce the usage of sediment or seawater suspended particulate matter (SPM) samples. The parameters of accelerated solvent extraction and LVI of target GDGTs were optimized. Under optimal conditions, the LVI approach (500 μL injection) coupled with LC–APCI–MS could determine various GDGTs even with 0.02–0.10 g of sediment samples or SPM samples collected from 0.2–1.0 L of marginal sea water or 10–20 L of open ocean seawater with satisfactory method precision (relative standard deviations ≤10.2%) and linearity (R2 ≥ 0.991). Compared with the classical method, the LVI–LC–APCI–MS required significantly reduced amount of sediment or SPM sample. Finally, the proposed method was applied to determine GDGTs in real sediment samples collected from hydrothermal vent sites at the Southwest Indian Ridges. Four groups of GDGTs, namely, isoprenoid GDGTs (isoGDGTs), branched GDGTs, H-GDGTs and OH-GDGTs, and archaeol, glycerol dialkanol diethers (GDDs) and glycerol monoalkanediol diethers (GMDs) were detected with only 0.02 g of sediment sample collected from Longqi and Tianzuo hydrothermal fields. The organic matter in the sediment sample from Tianzuo was significantly affected by hydrothermal activity. In addition, isoGDGTs in seawater SPM from the open area of Eastern Indian Ocean were investigated for the first time. Six common isoGDGTs were all detected in surface and subsurface SPM samples (filtering 10 L of seawater), which indicated that the LVI approach could noticeably reduce the workload of collecting seawater SPM on board and could be used to investigate conveniently the distribution of GDGTs in water column especially in open oceans and deep seas.

Mutagenicity of the Danube River: The contribution of liquid phase and particulate suspended matter.

Bioassays have been used to complement the chemical characterization of aquatic mutagenicity, but the tests sometimes are done only with water liquid phase (LP). Particle-bound mutagens are important because they can be ingested by filtering organisms. Our objective was to evaluate the mutagenicity of organic extracts of the LP and the water suspended particulate matter (SPM) from 13 sites along Danube River with the Salmonella/microsome microsuspension assay using TA98, YG1041, TA1538, and YG5185 strains. A high incidence of mutagenicity was detected, 84% for LP and 92% for SPM samples. The contribution of SPM to the mutagenicity was relatively small when compared with LP however, for five sites SPM was responsible for the whole mutagenicity, highlighting the importance of analyzing SPM when assessing water mutagenicity. YG1041 was the most sensitive strain and should be considered in future water mutagenicity monitoring programs, but it will depend on the main pollution sources.

Occurrence and seasonal distribution of steroid hormones and bisphenol A in surface waters and suspended sediments of Quebec, Canada

Limited information is available regarding the seasonal and spatial distribution of endocrine disrupting compounds (EDCs) in Canadian surface waters. Using improved analytical methods, we set out to evaluate the occurrence and risks of 15 EPA-priority EDCs in the St. Lawrence River and its main tributaries (69 locations). Surface water samples were also collected during a complete seasonal cycle along the Mille Iles River (17 locations), a tributary impacted by wastewater effluents and sewer overflows. In total, 137 surface water samples were analyzed for steroid hormones (altrenogest, androstenedione, equilin, equilenin, ethinylestradiol, α-estradiol, β-estradiol, estriol, estrone, levonorgestrel, medroxyprogesterone, norethindrone, progesterone, testosterone) and bisphenol A, in both the dissolved phase and suspended particulate matter (SPM). Of the 15 targeted EDCs, 14 compounds presented positive detections in the dissolved phase and 13 in the SPM. Summed EDC concentrations were reported in the range of 0.4–73 ng L−1 in dissolved phase samples and 0.1–228 ng g−1 in SPM samples. Bisphenol A was rarely detected in the dissolved phase but accumulated at high levels in suspended solids. Summed concentrations of hormones were generally higher during the spring and winter seasons, and lower during the summer. Estradiol (β-E2) presented the most frequent exceedances to the predicted no-effect concentration threshold (28/137 samples above the PNEC, or 20%), while a few exceedances were also reported for ethinylestradiol (4/137 above the PNEC, or 3%). The total estrogenic activity (EEQtotal) was higher than the threshold of 1 ng E2 L−1 for 26/137 samples, with estriol (E3) and β-E2 the preponderant contributors.

Legacy and Emerging Per- and Polyfluoroalkyl Substances Behave Distinctly in Spatial Distribution and Multimedia Partitioning: A Case Study in the Pearl River, China

Per- and polyfluoroalkyl substances (PFASs) have attracted worldwide attention due to their ubiquitous occurrence, bioaccumulation, and toxicological effects, yet the fate of PFASs in a lotic ecosystem is largely unknown. To elucidate spatial distribution and multimedia partitioning of legacy and emerging PFASs in a lotic river flowing into an estuary, PFASs were synchronously analyzed in water, suspended particulate matter (SPM), sediment, and biota samples collected along Guangzhou reach of the Pearl River, South China. Geographically, the concentrations of PFASs in the water phase showed a decreasing trend from the upper and middle sections (urban area) to the down section (suburban area close to estuary) of the river. While perfluorooctanoic acid predominated in water and SPM, more diverse compositions were observed in sediment and biota with the increase in contributions of long-chain PFASs. Field-derived sediment-water partitioning coefficients (Kd) and bioaccumulation factors (BAFs) of PFASs increased with the increase in perfluorinated carbons. Besides hydrophobicity, water pH and salinity significantly affected the multimedia partitioning of PFASs in a lotic ecosystem. In addition, 87 homologues (63 classes) were identified as emerging PFASs in four media using suspect analysis. Interestingly, Kd and BAF of the emerging PFASs were often higher than legacy PFASs containing the same perfluorinated carbons, raising a special concern on the environmental risk of emerging PFASs.

Equilibrium sampling of suspended particulate matter as a universal proxy for fish and mussel monitoring

Bioaccumulation of persistent and hydrophobic organic compounds in the aquatic environment puts secondary consumers, such as fish, at risk. To assess their exposure, monitoring programs with high numbers of individuals have been conducted worldwide over decades that require major efforts and raise ethical issues. This study aimed at testing suspended particulate matter (SPM) as an alternative and accessible abiotic matrix to estimate the internal exposure concentrations of such chemicals in fish and mussels. Muscle tissues of bream (Abramis brama), tissues of zebra mussels (Dreissena polymorpha) and SPM were collected from four major German rivers, Elbe, Danube, Saar and Saale, in 2018 within the national monitoring program of the German Environmental Specimen Bank. We used (i) total solvent extraction for biota samples to quantify the lipid-normalized concentrations of polychlorinated biphenyls, polycyclic aromatic hydrocarbons and hexachlorobenzene and (ii) passive equilibrium sampling of SPM to derive equilibrium partitioning concentrations in lipids and (iii) set these independent data sets into context. Since the ratio of lipid-normalized concentration / equilibrium partitioning concentration in lipids was in most cases < 1.0, SPM may serve as a conservative proxy for the internal concentration of bream and mussels, although bream of high age (i.e., older than 10 years) showed a tendency for this ratio to exceed 1.0. This observation indicates that age-dependent biomagnification can exceed the predictions based on thermodynamic equilibrium relative to SPM.

Levels and Distribution of Organophosphate Esters (OPEs) in Typical Megacity Wetland Park Landscape Water Bodies in Southwest China.

Human activities have led to the release of organophosphate esters (OPEs) into the environment. This study aims to investigate the levels and partitioning of OPEs in surface water, suspended particulate matter (SPM) and sediments of landscape waters across eleven parks in the city of Chengdu, a megacity in Southwest China. The average concentration of Σ6OPEs in the SPM samples (median: 2.94 × 103ng/L, 6.88 × 104ng/g dry weight) was 1-3 orders of magnitude higher than that in the surface water (median: 359ng/L) and sediment (median: 82.8ng/g) samples. Tri-n-butyl phosphate (TnBP), tris-(2-chloroethyl)-phosphate (TCEP) and trichloropropyl phosphate (TCIPP) were the primary OPE pollutants in the surface water and SPM samples, while TnBP, tris-(2-butoxyethyl) phosphate (TBEP) and tris-(2-ethylhexyl) phosphate (TEHP) predominated the sediment samples. The higher log Koc values of OPEs in park landscape water bodies estimated in the present study relative to previous studies could be explained by the environmental conditions, such as the sources of the inputs and the hydraulic retention times in these surface waters.

Gridded distribution of total suspended particulate matter (TSP) and their chemical characterization over Delhi during winter.

In the present study, total suspended particulate matter (TSP) samples were collected at 47 different sites (47 grids of 5 × 5 km2 area) of Delhi during winter (January-February 2019) in campaign mode. To understand the spatial variation of sources, TSP samples were analyzed for chemical compositions including carbonaceous species [organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC)], water-soluble total nitrogen (WSTN), water-soluble inorganic nitrogen (WSIN), polycyclic aromatic hydrocarbons (16 PAHs), water-soluble inorganic species (WSIS) (F-, Cl-, SO42-, NO2-, NO3-, PO43-, NH4+, Ca2+, Mg2+, Na+, and K+), and major and minor trace elements (B, Na, Mg, Al, P, S, Cl, K, Ca, Ti, Fe, Zn, Cr, Mn, Cu, As, Pd, F, and Ag). During the campaign, the maximum concentration of several components of TSP (996 μg/m3) was recorded at the Rana Pratap Bagh area, representing a pollution hotspot of Delhi. The maximum concentrations of PAHs were recorded at Udhyog Nagar, a region close to heavily loaded diesel vehicles, small rubber factories, and waste burning areas. Higher content of Cl- and Cl-/Na+ ratio (>1.7) suggests the presence of nonmarine anthropogenic sources of Cl- over Delhi. Minimum concentrations of OC, EC, WSOC, PAHs, and WSIS in TSP were observed at Kalkaji, representing the least polluted area in Delhi. Enrichment factor <5.0 at several locations and a significant correlation of Al with Mg, Fe, Ti, and Ca and C/N ratio indicated the abundance of mineral/crustal dust in TSP over Delhi. Principal component analysis (PCA) was also performed for the source apportionment of TSP, and extracted soil dust was found to be the major contributor to TSP, followed by biomass burning, open waste burning, secondary aerosol, and vehicular emissions.

Carbon and nitrogen isotope constraints on source and variation of particulate organic matter in high-latitude agricultural rivers, Northeast China

The release of biospheric organic matter (OM) stored in the humus-rich black soils of Northeast China is highly susceptible to permafrost thaw and agriculturally induced erosion processes, and plays a disproportionate role in the global carbon cycle. However, the perturbations of global change and anthropogenic activities on riverine export of particulate organic carbon (POC) in the high-latitude agricultural areas remain poorly constrained. In the present study, this knowledge gap was filled by identifying the provenances of particulate organic matter (POM) and the erosional flux of POC from the rivers draining Northeast China. The elemental (POC%, PON% and C/N ratio) and isotopic (δ13C and δ15N) compositions of POM in suspended particulate matter (SPM) from the rivers in Northeast China (the Songhua River (SRB) and Liao River basins (LRB)) were analyzed. The results showed that during the wet season, the δ13C and δ15N values of POM in SPM were −25.8 ± 1.2‰ and 6.6 ± 2.2‰ respectively. Elemental and isotopic characteristics of the SPM samples and potential sources indicated that the sources of POM differed significantly among different sampling periods and sites. During the wet season, Soil OM was the primary POM contributor. Compared to the SRB, autochthonous OM made relatively larger contributions to POM in the LRB. During the dry season, for the SPM samples mainly from the LRB, the δ13C and δ15N values of POM were −22.7 ± 4.3‰ and 3.1 ± 2.4% respectively, suggesting that effluent detritus was the predominant source. The flux and yield of SPM revealed the seasonal and spatial variations of physical erosion rate that controls POC export. Seasonally, up to 61% of the annual SPM load and 58% of the annual POC flux of the SRB occurred in May and August due to thawing processes and increasing precipitation. Spatially, the lower reaches of the SRB had the highest SPM yield and contributed more than half of the annual SPM load of the SRB, likely attributable to the high intensity of agricultural activities. Globally, the POC% in SPM and POC yield of the SRB were larger than a series of the world's largest rivers under a given SPM condition, suggesting the high sensitivity of terrestrial OM export to erosion. These findings highlight the perturbation and mobilization of terrestrial OM in Northeast China under intensive agricultural activities and ongoing global climate change.

Degradation and Aging of Terrestrial Organic Carbon within Estuaries: Biogeochemical and Environmental Implications.

Estuaries are action zones for organic carbon (OC) degradation and aging. These processes influence the nature of terrestrial OC (OCterr) export and the magnitude of OCterr burial in marginal seas, with important environmental implications such as CO2 release and hypoxia. In this study, we determined the contents and carbon isotopic compositions (13C and 14C) of bulk OC and fatty acids (FAs) as well as the sedimentological characteristics of suspended particulate matter (SPM) samples collected from two sites over four seasons and of surface sediment samples from three sites in the Pearl River estuary (PRE) to evaluate processes controlling OCterr degradation and aging along an estuarine gradient. We found that the abundance-weighted average C24-32FA 14C ages increased by an average of ∼1170 years for SPM and by an average of ∼3440 years in PR/PRE sediments, along the ∼60 km PRE transect. These increases in the FA age coincided with an 86% decrease in the corresponding mineral surface area-normalized FA loading along the sediment transport pathway, implying that selective degradation of labile and younger OC resulted in apparent OC aging. These measurements reveal an important shift in the nature of OC, with implications for biogeochemical cycling within estuaries and for regional environmental changes.

Heavy metals in the “plastisphere” of marine microplastics: adsorption mechanisms and composite risk

Heavy metals that are adhered to the surfaces of microplastics in the natural marine environment pose potential threats to marine life. However, little is known about their adsorption mechanisms and composite risks. This study collected seawater, suspended particulate matter (SPM), plankton, and microplastic samples from the waters surrounding Hong Kong, established a method for analyzing 13 heavy metals in the plastisphere, and explored the extrinsic and intrinsic sources of the heavy metals by analyzing natural matrices (seawater, SPM, and plankton) and anthropogenic plastics. We found that heavy metals in the plastisphere were significantly affected by the surrounding matrices, as indicated by its positive correlations with the heavy metals in SPM and plankton at most of the sampling sites. Heavy metals in plankton usually occurred as traces of oxides such as As2O3 and ZnO. The partition coefficients of the studied heavy metals between seawater and the plastisphere were identical to those between the SPM and the plastisphere. No correlations were found between the concentrations of heavy metals in the plastisphere and the heavy metal concentrations, masses, quantities, or surface areas of the microplastics, although some polymer types contained extremely high Cd (676 mg/kg), Pb (1,742 mg/kg), and Zn (1,712 mg/kg) concentrations. Only the Cr, Cu, and Ni concentrations were positively correlated with the specific surface area of the microplastics. A cluster analysis showed that Cr, Cu, and Ni were derived from anthropogenic sources, indicating that adventive heavy metals could be adsorbed by plastics with large specific surface areas. We also established a new composite risk assessment method for heavy metals and microplastics that leverages the specific surface areas of microplastics. The assessment results showed that Cd from Tolo Harbor had a strong ecological risk, while As and Cd from the eastern waters off Hong Kong had moderate composite ecological risks.

Relevance of using the non-reactive geochemical signature in sediment core to estimate historical tributary contributions

Fluvial suspended particulate matter (SPM) fluxes transport large amounts of contaminants that can affect water quality and river ecosystems. To better manage these inputs in river systems, it is essential to identify SPM and sediment sources. Many studies have applied a fingerprinting method based on using metals integrated into a numerical mixing model to estimate source contributions in a watershed. Most fingerprinting studies use contemporary SPM to trace historical inputs, whereas their metal concentrations were modified over time due to anthropogenic inputs. Moreover, total concentrations of these properties are subject to change due to diagenetic processes occurring in stored sediments. The aim of this study was to assess the relevance of using the non-reactive fraction of metals (i.e. metals and metalloids) in fingerprinting studies to estimate the historical contributions of SPM tributary inputs in a sediment core. To assess metal concentrations in the ‘conservative’ (i.e. non-reactive) fraction, SPM (samples of sources) and sediment core layers (targeted sediments) were subjected to total mineralization and soft extraction, and the non-reactive fraction was obtained by calculating the difference between the two extractions. This approach was applied on a sediment core from the Upper Rhône River (France), using geochemical signature in contemporary SPM of three major tributaries. We showed that the non-reactive fraction retains a higher number of metals in the range test for the deepest layers, which are characterized by significant anthropogenic inputs. Through apportionment modelling using Monte Carlo simulation, we demonstrated that the tributary contributions computed using the non-reactive fraction are more consistent with historical flood and water flow data and have lower uncertainties than with the total fraction. Working with the non-reactive fraction made it possible to decipher historical inputs of SPM using contemporary SPM samples. This approach enables robust identification of sub-catchment areas liable to provide large quantities of SPM. The non-reactive fraction can be used in a variety of environmental conditions and at various spatial and temporal scales to provide a robust quantification of sediment sources.

Energy dispersive X‐ray fluorescence methodology and analysis of suspended particulate matter in seawater for trace element compositions and an intercomparison with high‐resolution inductively coupled plasma‐mass spectrometry

AbstractA modification of energy dispersive X‐ray fluorescence (ED‐XRF) for analysis of trace element concentrations in suspended particulate matter (SPM) in seawater and intercomparison with high‐resolution inductively coupled plasma‐mass spectrometry (HR ICP‐MS) is presented. Approximately 250 SPM samples were collected on polycarbonate track‐etched filters in the Indian Ocean during the U.S. CLIVAR/CO2 Repeat Hydrography meridional section I09N cruise in 2007. Samples were first analyzed by ED‐XRF, a nondestructive technique, for Al, P, Ti, Mn, Fe, Ni, Cu, and Zn and subsequently digested and quantified by HR ICP‐MS, creating two blind, basin‐scale data sets used for a paired statistical comparison. Our results found (1) ED‐XRF analysis using thin‐film principles can quantify the elemental composition of SPM at nanomolar concentrations found in the open ocean; (2) there was excellent agreement between ED‐XRF and HR ICP‐MS analyses for Al, Fe, and Mn and good agreement for P and Ti; (3) analytical differences were the largest for Cu, Ni, and Zn; (4) HR ICP‐MS methods have lower detection limits for most elements when compared to the ED‐XRF; (5) ED‐XRF analysis has a closer agreement to reported values for the NIST SRM 2783 standard and lower relative standard deviations when compared to the HR ICP‐MS. We recommend continued refinement of nondestructive ED‐XRF methods as this would allow for the easy exchange of filtered samples between lab groups for intercalibration and intercomparison of basin‐scale hydrographic cruises and archival for future analysis.

Polycyclic aromatic hydrocarbons (PAHs) in the non-bleached and bleached corals and their ambient environment: The role of suspended particulate matter, mucus, and positive matrix factorization model for identifying contributions to the carcinogenicity of PAH sources

This study investigates levels of polycyclic aromatic hydrocarbons (PAHs) in the corals (tissue, skeleton, zooxanthellae, mucus) and their ambient environment (surface sediment, seawater, suspended particulate matter (SPM)), with a special focus on SPM and mucus. The Σ37PAH concentrations ranged from 89 to 206 ng g−1 dw in SPM, 52 to 116.1 ng g−1 dw in the sediment and from 18.6 to 91.9 ng L−1 in the seawater. Among the coral components, mucus contained the highest PAH loadings reaching up to 369.2 ng g−1 dw. Coral morphology and pollution of their ambient environment were identified as the main factors affecting the PAH bioaccumulation. Massive corals T. reinformes and P. compressa living in heavier polluted sites accumulated the highest PAH concentrations. Diagnostic ratios provided inconsistent source apportionment results, but positive matrix factorization (PMF) analysis identified gasoline/diesel (vehicle) emission (F1), oil spills (F2), coal (F3), and wood (F4) combustion as the main PAHs sources in the study area. Contribution to carcinogenic potencies of PAHs in sediment samples decreased in the following order: F1 > F2 > F3. Factor F4 did not affect the carcinogenic properties of the surface sediment samples but was found to contribute significantly to the TEQBaP values of the SPM samples. The results of this study indicate a direct interaction between SPM and the coral mucus and imply that SPM plays an important role in the pollution transfer and bioaccumulation processes in corals.

Terrestrial inputs govern spatial distribution of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in an Arctic fjord system (Isfjorden, Svalbard).

Considerable amounts of previously deposited persistent organic pollutants (POPs) are stored in the Arctic cryosphere. Transport of freshwater and terrestrial material to the Arctic Ocean is increasing due to ongoing climate change and the impact this has on POPs in marine receiving systems is unknown This study has investigated how secondary sources of POPs from land influence the occurrence and fate of POPs in an Arctic coastal marine system. Passive sampling of water and sampling of riverine suspended particulate matter (SPM) and marine sediments for analysis of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) was carried out in rivers and their receiving fjords in Isfjorden system in Svalbard. Riverine SPM had low contaminant concentrations (<level of detection-28pg/g dw ΣPCB14, 16-100pg/g dw HCB) compared to outer marine sediments 630-880pg/g dw ΣPCB14, 530-770pg/g dw HCB). There was a strong spatial gradient in sediment PCB and HCB concentrations with lowest concentrations in river estuaries and in front of marine-terminating glaciers and increasing concentrations toward the outer fjord. This suggests that rather than leading to increased concentrations, inputs of SPM from land lead to a dilution of contaminant concentrations in nearshore sediments. Preliminary estimates of SPM:water activity ratios suggest that terrestrial particles (with low contaminant concentrations) may have the potential to act as sorbents of dissolved contaminants in the coastal water column, with implications for bioavailability of POPs to the marine food web. There is concern that ongoing increases in fluxes of freshwater, sediments and associated terrestrial material (including contaminants) from land to the Arctic Ocean will lead to increased mobilization and transport of POPs to coastal ecosystems. However, the results of this study indicate that on Svalbard, inputs from land may in fact have the opposite effect, leading to reduced concentrations in coastal sediments and waters.

Multi-matrix approach reveals the distribution of pesticides in a multipurpose protected area from the Atlantic Rainforest: potential risk for aquatic biota and human health?

The Atlantic Rainforest is among the main biodiversity hotspots in the world, the Yabotí Biosphere Reserve (YBR) being one of the most important remaining areas. Agriculture practices could lead to intensive usage of pesticides resulting in a risk to the environment and human health. Water, suspended particulate matter (SPM), sediment, and fish (Andromakhe paris and Andromakhe saguazu) samples were collected from four streams with different degrees of protection of the YBR in two periods in order to assess the distribution of 18 organochlorine pesticides. Legacy and current-use pesticides were found in the different environmental matrices of the stream headwaters in non-anthropized areas within the buffer zone that drains the intangible area. A similar occurrence pattern of pesticides was found in all matrices. Levels of DDTs (<3.63 ng/L) and endosulfans (<21.8 ng/L) in surface water were above international guidelines for the protection of aquatic life in several streams for both sampling periods. HCHs, DDTs, endosulfans, and chlorpyrifos were detected in SPM and sediments from three streams, while γ-HCH (<60.3 ng/g lipid weight), chlorpyrifos (<698 ng/g lw), p,p´-DDD (<367 ng/g lw), and α-endosulfans (<209 ng/g lw) were detected in fish muscle in several streams. Chlorpyrifos and endosulfans were associated with current use, while DDx/DDT ratios suggested an old use. The concentration of pesticides found would not represent a risk to human health; however, it highlights the need to establish better regulation and action guidelines to reduce the anthropogenic effect on natural reserves.

Latitudinal changes in the trophic structure of benthic coastal food webs along the Antarctic Peninsula

Stable isotopes of C and N have been used to assess the effect of the duration of the sea ice season on the structure of benthic, Antarctic coastal food webs. Samples of suspended particulate organic matter, macroalgae and macroinvertebrates were collected at five subtidal rocky sites across a latitudinal gradient along the western Antarctic Peninsula and among the South Shetland Islands. We tested the hypotheses that trophic positions of omnivores decrease, and food web structure becomes more redundant at higher latitudes. A latitudinal shift in the isotope baseline was detected for both δ13C and δ15N, but the trophic positions of macroinvertebrates and their relative positions along the δ13C axis and were basically constant across sites, even after rescaling stable isotope ratios to account for shifts in the baseline. Although the northernmost and southernmost study sites differed significantly in most of the metrics of the food web structure, changes with latitude and the duration of the sea ice season were non-monotonic. Highly productive phytoplankton blooms during the ice-free season at Esperanza Bay and Rothera Point may explain the observed pattern, as they result in a massive supply of planktonic organic matter to the detritus bank in the seabed and, hence, shorten the C range and increase trophic redundancy. If this hypothesis is correct, the intensity of the summer phytoplankton bloom can be as relevant for the structure of the benthic marine food web as the duration of the sea ice season.