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This study presents morphological descriptions and ecological information for 58 terrestrial pollen taxa and seven water-related pollen taxa from the Brazilian Cerrado, obtained from two sediment cores, Lake Feia (LFB1) and Getulio Swamp (VGE-17), encompassing the last 5000 and 15,000 cal yr BP, respectively. The relationships between the ecological and morphological traits (pollination syndrome, vegetation stratum and grain size) within each of the two depositional environments were investigated. In the LFB1 core, the pollen assemblages were dominated by arboreal pollen from closed physiognomies and lower storey trees (<10 m in height), while a combination of closed and open physiognomies was observed in the pollen assemblages from the VGE-17 core. The vast majority of the pollen taxa exhibited the entomophilous pollination syndrome, and a higher influx of entomophilous pollen was observed in both cores. Anemophilous and anemophilous/entomophilous syndromes were less well represented. Small and medium pollen grain classes were the most abundant, while the large pollen grain class was rare. The influx of small pollen grains was slightly more abundant in the lake record, while in the swamp record medium pollen grains were more abundant. Our results show that swamps and lakes differ in their representation of local versus regional pollen and in their sensitivity and responses to water-level changes. Landscape physiognomy also influences pollen dispersion: a closed physiognomy increases the local pollen signal, while a more open physiognomy results in better representation of local and regional signals. [ABSTRACT FROM AUTHOR]

Chemical analysis, grain size distribution and short-lived radionuclides (210Pb and 137Cs) were combined to investigate the sedimentary processes in the Oualidia lagoon. Grain size and major elements profiles indicate an unexpected change in the layers characterising 1978 and 1986. Sediment accumulation rates (SAR) depth profiles exhibited the same behaviour and revealed two different sediment deposition conditions or regimes, involving modification of this ecosystem equilibrium. The profiles of major elements behave vertically almost the same as SAR, and grain size distribution. The observed changes reflect modifications in sediments supply and ecosystem drivers due to the variation of hydrodynamics conditions, confinement phenomena located in the upstream zone of the lagoon and to the various anthropogenic activities around the Oualidia lagoon. [ABSTRACT FROM AUTHOR]

This study's objective was to evaluate the depth profiles of rare earth elements (REEs) in two Pb-210 dated sediments cores retrieved from the Oualidia lagoon, reconstruct their anthropogenic history, and assess their potential ecological risk. The sediment cores analysis was carried out using instrumental neutron activation analysis. Other physical-chemical parameters (bulk, organic matter, grain size) were also measured. The results indicated that the highest values were recorded in the topmost layers of the sediment cores and depleted with depth. The historical records of REEs revealed an exponential increase in their concentrations from the 50s. The enrichment factor, geo-accumulation index, and contamination factor calculated for each sediment core layer have exhibited important concentrations of Gd, Sm, and Eu, suggesting an anthropogenic origin of detected elements. Based on ecological risk >40 and the risk index >220, Gd, Eu, and Sm pose a high risk on the study area, while the other elements present moderate and mild risk. The obtained results revealed an increasing tendency of REEs accumulation into the Oualidia lagoon and suggested that a new source is feeding the lagoon sediments by these elements. These findings provided a clear picture of REEs evolution between 1903 and 2014 and baseline information on the historical deposition of these elements in the Oualidia lagoon. [ABSTRACT FROM AUTHOR]

Wetlands are one of the most important ecosystems on earth, which help sustain life, yet they are reported to be at the receiving end of the high rate of pollution. The state of Kerala on the southwest coast of India is bestowed with several wetlands including Ramsar sites. Although the larger wetlands have been extensively studied, smaller or local wetlands have often been neglected; however, the environmental problems will be first reflected in the small wetlands. In this study, the ecological risk assessment of core sediments of one such site, the Biyyam wetland, a wetland of national importance, is reported for the first time. Sediment core samples were collected from four different stations of Biyyam wetland, and concentrations of heavy metals such as Ni, Zn, Mn, Cu, Cd, and Pb were determined. Statistical analysis indicated that correlation among different metals differed with respect to stations, but the percentage of organic matter showed a positive correlation with the concentration of the metals. The mean concentrations of Ni, Pb, and Cd exceeded the global average shale value. The quality of the sediments was assessed based on numeric Sediment Quality Guidelines. The degree of Contamination, Pollution Load Index, Enrichment Factor, Geoaccumulation Index, Ecological Risk Index, Toxic Unit, and Toxic Risk Index were used to evaluate the ecotoxicity of the heavy metals in the sediment core samples. The results inferred serious anthropogenic pollution in the wetland, and Cd was reported as the prominent metal contributing to heavy metal toxicity and ecological risk in the study area, which may in long run be toxic to the aquatic ecosystem. [ABSTRACT FROM AUTHOR]

Bryophyte diaspore banks are a critical aspect of the life strategy of some species yet remain neglected and poorly understood. This study investigated the longevity in natural habitat of the diaspore bank of Physcomitrium eurystomum Sendtn., a moss species that is threatened with extinction in Europe. Undisturbed soil cores of 40 cm depth were collected from Langmere, Norfolk, UK, and were split into investigated sediment layers of 1 cm depth. Dating of sediment layers was done by an analysis of radionuclides, and diaspore germination trials of each layer were carried out in a growth chamber. DNA barcoding was used to help identify plants that germinated. Viable diaspores of Physcomitrium eurystomum frequently occurred in sediment layers that were at least 100 years old and continued to occur in much lower layers that were probably several hundred years old. The long-term survival of bryophytes underground can have important implications for conservation decisions. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) were detected by gas chromatography–mass spectrometry in the sediment core form Poyang Lake. The concentrations of Σ17 PBDEs and Σ15 PAHs ranged from 1.13 to 4.64 ng/g, and from 341 to 744 ng/g, respectively. The Rock-Eval test was conducted to obtain organic matter parameters such as total organic carbon (TOC), S2, and hydrogen index (HI). The value of TOC, S2, and HI showed an increasing trend from the bottom to the surface. Source analysis results showed that the source of PAHs was combustion. Moreover, the correlation analysis of PBDEs, PAHs, and annual average temperature with S2 and HI showed that BDE-202, BDE-201, BDE-183, and BDE-154 were negatively correlated with S2 and HI, while BDE-85 and BDE-47 were positively correlated. There was no significant correlations of PAHs with S2 and HI, which is related to the disturbance of sediments. It is interesting that significantly positive correlation of HI with five-year moving averages of the air temperature was demonstrated, demonstrating that the climate warming enhanced the increase of algae in the Poyang Lake. [ABSTRACT FROM AUTHOR]

The present study investigates the vertical distribution of organochlorine pesticides (OCPs), in two sediment cores collected from the Bizerte Lagoon. The sediment core (SC1) is located in the mouth of the channel connecting the lagoon to the Mediterranean Sea and characterized by the industrial and urban activities of zone A and B. The sediment core (SC2) is situated in the zone D known by its intensive metallurgy and naval construction activities. The OCPs concentrations ranged from 26.98 ± 0.04 ng g−1 found at 3 cm depth and 10.23 ± 0.02 ng g−1 at 6 cm depth in SC1, and varied between 11.77 ± 0.11 ng g−1 at 9 cm depth and 1.47 ± 0.02 ng g−1 at 20 cm depth in SC2. The results showed that the SC2 had lower levels of OCPs and total organic carbon (TOC) compared to SC1. Generally, OCPs and TOC % decreased with depth along the two SCs profiles. The different categories of OCPs were in the following order: DDTs> Aldrin >HCB. The principal OCPs in deeper sediment layers were aldrin, endrin, and ∑DDTs for SC1 in addition to HCB and aldrin for SC2. The predominant OCPs in surface sediments were dieldrin, endrin and ∑DDTs for SC1, and HCB, heptachlor, aldrin and ∑DDTs for SC2. Different profiles were observed making evident that the levels of these pollutants depend strongly on anthropological discharges from industrial, urban and farming sources. The temporal trends of OCPs were influenced by their different historical usages, different properties or different degradation conditions in the environment. DDTs was mainly due to historical residue and biodegradation occurred in aerobic conditions. According to the established guidelines for sediment quality, levels of OCPs at most of the SCs layers were below class criteria. However, levels of DDE in SC1 could cause biological damage and ecotoxicological risk. [ABSTRACT FROM AUTHOR]

This review focuses on the sedimentary records of polycyclic aromatic hydrocarbons (PAHs) in China and the worldwide. We provide a global image of sedimentary record of PAHs in different regions, including their contents, vertical profiles, and possible sources. Generally, historical PAHs recorded in China, dominated by biomass burning and domestic coal combustion, are moderate on the global scale with an upward trend while elevated levels of historical PAHs are usually found in developed countries with a downward trend. This review ends with some concerns about historical PAHs in sediments and some directions deserved further efforts. [ABSTRACT FROM PUBLISHER]

In this study, we collected two sediment cores (C1 and C2) from the Andong tidal flat, Hangzhou Bay, and studied the temporal variations of heavy metals in the cores. Vertical distributions of heavy metals were almost unchanged in both the cores before 2000. After 2000, however, the heavy metal concentrations increased dramatically, suggesting that the sediments have been affected by enhanced human pollution in the recent decade. In the core C1, the sediments were severely polluted by Pb, moderately to considerably polluted by Cr and Zn, and low to moderately polluted by other heavy metals. The core C2 was relatively unpolluted before 2000 and low to moderately polluted after 2000. Multi-statistical analyses indicated that the core C1 was additionally contaminated by local human activities such as wastewater discharge and the Hangzhou Bay Bridge. The heavy metals in the core C2, however, were largely contributed by the Yangtze River and controlled by sedimentation process. The calculated sedimentary flux (4–8 g m−2a−1) of heavy metals generally increased with time. It was closely related to the wastewater discharge in adjacent areas. This study reconstructed the local heavy metal pollution history and provides important information for environmental protection and policy making. [ABSTRACT FROM AUTHOR]

The main objective of this investigation is to determine the concentration and accumulation of heavy metals in the coastal sediments of the Southeastern Black Sea of Turkey. The selected sampling area has mainly been affected by anthropogenic activities, such as agricultural, untreated domestic and treated industrial wastewater, and mining. Metal enrichment factor (EF), geo-accumulation index (Igeo), and metal pollution index (MPI) have been calculated and relative contamination levels evaluated at all stations. In this study, the maximum EF values calculated for nickel (Ni), cobalt (Co), cadmium (Cd), lead (Pb), chromium (Cr), arsenic (As), zinc (Zn), and copper (Cu) were 1.4, 3.1, 5.2, 7.8, 7.8, 20, 26, and 42, respectively. Metal pollution has decreased in recent years, but the enrichment of heavy metals has been observed to be relatively high, especially in the uppermost 3-6 cm of the core sample from the Sürmene sampling station, which has been polluted by mining activities. In addition, factor analysis revealed that the coastal sediments from the Eastern Black Sea were influenced by several sources, namely lithogenic and anthropogenic activities (mining, wastewater discharging, agriculture). [ABSTRACT FROM AUTHOR]

Sediment core samples were obtained from Nishiyama Reservoir, 3 km east of the hypocenter of the Nagasaki atomic bomb, to evaluate both sources and inventories of lead delivery to the sediments. Using microwave digestions and ICP-MS analytical techniques, elevated concentrations of isotopically unique lead were identified in the 1945 sediment horizon. These results illustrate that the Nagasaki bomb attack can be linked with unique lead loading to the sediments in the region of the hypocenter. There is a possibility that the roll-up of in-situ lead accounted for a majority of the increase in lead flux delivered to reservoir sediments during the atomic bomb attack. [ABSTRACT FROM AUTHOR]

Perfluorinated alkylated substances (PFAS) have been determined in surface sediments and sediment core from Gulf of Gdańsk, Baltic Sea. Perfluorooctanesulphonate (PFOS), perfluorohexanesulphonate (PFHxS), perfluorodecanoate (PFDA), perfluoronanoate (PFNA), perfluorooctanoate (PFOA), perfluoroheptanoate (PFHpA), perfluoroundecanote (PFUnDA), perfluorododecanoate (PFDoDA) and perfluorohexanoate (PFHxA) were quantified after isotopic dilution (13C4 PFOS and 13C4 PFOA), liquid-liquid extractions by methanol and acetonitrile, cleanup by Envi-Carb, OasisWAX and Envi-Carb and final measurement by HPLC–MS/MS. PFOS, PFHxS, PFUnDA, PFDA, PFNA and PFOA were found in Baltic Sea sediments in concentrations exceeding the method limit of quantification (LOQ) of 2 pg/g. PFOS was detected in concentration up to 0.896 ng/g dry weight and PFHxS up to 0.326 ng/g dw, which shows on a weak pollution. PFOS (48–74%) or PFHxS (45–56%) dominated in PFAS composition of sediments surveyed. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Environmental Science and Health, Part A to view the free supplemental file. [ABSTRACT FROM PUBLISHER]

Over the past decade, Chini Lake has experienced tremendous changes due to land conversions from forest to agriculture such as oil palm and rubber plantations and also construction of a small barrage downstream of the Chini River. This land conversion has caused changes to the plant community and increased sedimentation rates in the lake. Consequently, this study was carried out to investigate the distribution patterns and sources of n-alkanes in four sediment core samples from Chini Lake and to evaluate the relative changes in organic matter inputs from land and lake flora. In the long-chain n-alkanes (LHC > C23)region, carbon preference index (CPI) values ranged from 1-1.52 in the sediment cores. Most lake sediments analyzed did not contain an unresolved complex mixture (UCM). The average nC17/pristane ratios (nC17/Pr) were 5.34 ± 1.99 and the average nC18/phytane (nC18/Ph) ratios were 1.27 ± 0.25 for the sediment profiles. The n-alkane average chain length (ACL) was 29.68 ± 0.15in the study area. There was significant positive correlation between ACL and CPI in the sediment cores at station B (r = 0.769, p = 0.003), station C (r = 0.735, p = 0.015), station D (r = 0.737, p = 0.006), and station E (r = 0.741, p = 0.006). Positive correlations between diploptene and long-chain n-alkanes (nC25-nC33) were found for sediment core B (r = 0.976, p<0.001), sediment core C (r = 0.836, p = 0.003), sediment core D (r = 0.824, p = 0.001) and sediment core E (r = 0.865, p < 0.001). Terrigenious to aquatic ratio for hydrocarbons (TARHC) and total n-alkanes (∑HC) concentrations increased with depth a pattern that contrast with short chain n-alkanes/total organic carbon (SHC/TOC) ratios. It can be concluded that the petrogenic hydrocarbon contamination in the sediment cores is minimal and that the n-alkanes preserved in Chini Lake sediments are influenced by higher plant waxes and bacteria. [ABSTRACT FROM AUTHOR]

Under the framework of the IAEA's Technical Co-operation project RAF7/004, international research cruises were carried out in 2004 to assess the distribution of radionuclides and micropollutants in the south-western Mediterranean Sea. Sediments samples had variable concentrations of total aliphatic hydrocarbons and polycyclic aromatic hydrocarbons ranging from 0.2 to 1.8 µg g-1 and 26.9 to 364.4 ng g-1, respectively, in the Sicily Channel and from 0.7 to 2.8 µg g-1 and 14.7 to 618.1 ng g-1, respectively, in the open sea of the Gulf of Tunis. Hydrocarbon concentrations changed with depth and were relatively high at 3 cm and 10 cm depths. The use of 'fingerprint' ratios of certain isomeric pairs of polycyclic aromatic hydrocarbons (PAH) and the proportion of 2-3 ring and 4-5 ring PAH concentrations showed that the main origins are characteristic of petroleum sources. The ranges of trace metal concentrations, expressed in µgg-1, in the Sicily Channel and in the Gulf of Tunis, respectively, were: Hg 0.009-0.2 and 0.02-0.1; Pb 9.9-26.1 and 21.2-32.5; Cd 0.06-0.1 and 0.07-0.33; Fe 23.7-28.1 and 29.9-36.2p; Zn 83-99.5 and 83-104; Mn 309.2-752.5 and 651-814; Cu 17.1-18.5 and 33.5-51.3. Sediment metal abundances were in the order: Mn > Zn > Fe > Cu > Pb > Cd > Hg. The results showed significant differences (p < 0.001) for trace metal and hydrocarbon mean concentrations between the two cores. These concentrations are generally similar to the background levels from the Mediterranean Sea and could be affected by physico-chemical conditions and sedimentation rate as well as biodegradation. [ABSTRACT FROM AUTHOR]

Partitioning of metals between dissolved and particulate sedimentaryphases provides useful information which can be used to assess theirmobility and sources. Bioavailability and toxicity has also been found in many cases to be related to metal partitioning. Sediment cores were taken from salt marsh areas in the Thames Estuary and along the Essex and North Norfolk coasts, and porewaters were separated by centrifugation and filtration. Concentrations of Cd, Cu, Fe, Mn, Ni and Pb in the porewaters, and in HCl/HNO3 digests of the total sediment, were determined by AAS. The order of metal mobility showed inter-site differences, indicating that the partitioning characteristics were influenced by physico-chemical and hydrodynamic controls. These inter-site differences were reflected in the partitioning distribution of Mn and the sediment redox potentials. Cadmium showed the strongest tendency to partition towards dissolved phases, and porewater concentrations decreased in the Essex salt marshes with increasing distance from the Thames. Lead was found to partition primarily towardssedimentary phases, indicating minimal mobility. The dissolved concentrations of Pb and Cu are not thought to represent an immediate threat to the salt marsh biota. [ABSTRACT FROM AUTHOR]