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High-altitude Pyrenean lakes are ecosystems far from local pollution sources, and thus they are particularly sensitive to the atmospheric deposition of metals and metalloids. This study aims to quantify the effect of human activity in 18 lakes located in both side of the France–Spain frontier. Sediment cores were collected in summer 2013, sampled at a 1cm resolution and the concentration of 24 elements was measured by ICP-MS. Statistic and chemometric analysis of the results highlights the influence of the geographical position and lithogenic features of each lake basin on trapping pollutants. More than the 80% of the lakes showed values of enrichment factor (EF) above 2 for at least one of the elements investigated in at least one core interval, which corroborates the existence of historical anthropogenic inputs of elements in the studied area. The results demonstrate the natural origin of As and Ti in Pyrenees, together with the significant anthropogenic inputs of Cd, Pb, Sb and Sn from ancient times. The data set points mining activities as the main historical source of pollution and illustrate the large impact of the industrial revolution. The regional variability could reflect also differential long-range transport, followed by dry or wet deposition.

Several long half-life natural and anthropogenic radionuclides, including 137Cs, 226Ra, 232Th, and 40K, in a 45 cm-long sediment core collected from the east continental shelf of Hainan Island, South China Sea, have been analyzed. The results showed that mean activity of 137Cs, 226Ra, 232Th, and 40K were 2.03 ± 1.2, 20.4 ± 1.8, 45.7 ± 3.0, and 520.0 ± 20.0 Bq/kg, respectively. Radium equivalent activity and External hazard index imply a low radiation, and the study area could serve as a background reference value for environmental radionuclides in east continental shelf of Hainan Island, South China Sea.

Radionuclides dating have been applied in the chronological series of sediment core recovered from Satopanth Tal to estimate the sedimentation rate and its age. Several models include CRS and slope method, and 137Cs peak methods have been adopted. The depth concentration of 210Pbexc in the core determines the various parameters like sedimentation rate, geochronology, inventory, and mass fluxes. The CRS model and slope method infer the sediments deposited at a rate of 0.79 ± 0.04 cm/year dated to 120 years. Distinct peaks on 1963 and 1986AD, the 137Cs record estimate the mean sedimentation rate is 0.745 ± 0.03 cm/year respectively and dated to 77 years.

This paper describes the pollution level in sediment core collected from Sunairi Point of Karachi coastal area Pakistan. The sediment was characterized in terms of particle size, pH, total organic carbon, calcium carbonate, metals and mineralogical composition of sediments. The metals were determined using proton induced X-ray emission. It appeared from the results of grain size that sediment of core was mainly sandy in nature and neutral pH was observed throughout the core. The calcium carbonate in the core sediment seemed to be dependent on the pH outline of the sediment. The results of heavy metals in the sediment core indicated a significant upward enrichment in heavy metals with the highest concentrations found in the upper most layer sediments, may be due to anthropogenic activities, which could be the cause of upward enrichment in heavy metals. The pollution load index values, although showed no pollution, but showing an increasing trend from bottom to top in core, may be due to the influence of anthropogenic sources. The average geo-accumulation index values for sediment core showed that sediments were moderately polluted with Co and Pb. The results of sediment quality guidelines of United States Environmental Protection Agency, indicated, sediment of core was moderately polluted with Ni and Zn. It was concluded from the guidelines that heavy metals in sediment may cause danger to aquatic life. It was also inferred from the study that Sunairi Point area of Karachi coast is facing moderately metals pollution which increased with time.

Sediment oxygen demand (SOD) measurement currently requires a long preparation time and bulky experimental equipment, which represent major obstacles to conducting SOD measurements. We developed a new SOD measurement method that can be easily conducted in a shorter time than the existing laboratory method. The undisturbed sediment core was transferred into the custom-made small glass vial (inner diameter 12.8 mm, length 125 mm). The SOD sample was incubated in the dark with or without stirring the overlying water inside the vial. The change in DO concentration was measured using a non-contact fluorescent oxygen sensor, and then the SOD was calculated. For comparison and verification of the new method, SOD was also measured using a large undisturbed sediment core (inner diameter 11 cm, length 50 cm). The SOD measurements using the new method were positively correlated with the SOD measurements using the large undisturbed sediment core, suggesting that the new method is a feasible alternative to the conventional method. In the new method, many SOD measurements can be taken from a single sediment core sample. This makes it possible to reduce the uncertainty associated with the highly heterogeneous structure of the sediments, and thus the new method has great advantages in obtaining reliable SOD data. A novel high-throughput method for SOD was developed that shortens sample preparation time and improves convenience of measurement. The new method is expected to contribute substantially to the accumulation of SOD monitoring data and to make great progress in elucidating the dynamics of dissolved oxygen in lakes.

Sediment cores retrieved from rivers, lakes, and coastal marine environment have been widely utilized to reconstruct historical variations of anthropogenic pollutants. A sediment core was collected in the Kizilirmak River, Turkey during 2014 and analyzed for a suite of metals (Cu, Pb, Zn, Ag, Ni, Co, Mn, As, Cd, Sb, V, Cr, Hg and Se) to reconstruct their temporal variations. Chronology was attempted using excess 210Pb (210Pbxs), 137Cs and 239,240Pu in the sediment cores. The vertical profile of excess 210Pb indicates that this core is not datable using excess 210Pb method. The 137Cs-based linear and mass apparent accumulation rates were estimated to be 0.84 cm year−1 and 0.93 g cm−2 year−1, respectively. These values are in agreement with the 239+240Pu peak-based linear (0.88 cm year−1) and mass apparent accumulation (0.97 g cm−2 year−1) rates. There is considerable broadening in the peaks of both 137Cs and 239,240Pu, likely due to post-depositional mixing processes. The measured sediment inventories of 210Pbxs, 137Cs and 239+240Pu were 38, 29, and 0.42 dpm cm−2, respectively, which were generally higher than the expected inventories based on local atmospheric depositional inventories. We attribute these enhanced inventories to potential sediment focusing and additional watershed erosional input. The Al-normalized enrichment factors (ANEF) were used to evaluate the contribution from natural versus anthropogenic sources. The ANEF of Ag, Ni, As, Cd and Se were > 1.5, which suggests a significant contribution of anthropogenic sources for these trace metals varied between 226% and 1163%. The geoaccumulation index (Igeo) values of the sediment column suggest that Cu, Pb, Zn, Co, Mn, Sb, V and Hg were in an unpolluted level and the others were in a polluted level. Besides, both the ANEF and Igeo values of Cu, Pb, Zn, Ag, As, Se, Cd and Hg showed a peak at 28–30 cm layer (corresponds to 1978–1981), which is attributed to maximum metal release during 1970s.

We collected a sediment core from the 6th (6J) Triglav Lake, a remote mountain lake in NW Slovenia, and analysed it for 25 elements, using k0-instrumental neutron activation analysis (k0-INAA). For Hg, we used cold vapour atomic absorption spectrometry (CVAAS). Data were analysed using Principal Component Analysis (PCA). PCA indicated several distinct groups of elements and sediment core samples. Ca distribution was entirely different from all other sediment components. Ba, Br, Hg, Sb and Zn were associated with organic matter (OM), with Hg showing the strongest affinity to OM. As, Cr, Fe and U formed a group of redox-sensitive elements. Two events that occurred ca. 1915 and in the 1940s/1950s, were identified in the core. They were associated with increased inputs of allochthonous material into the lake, and significantly affected the stratigraphic distributions of all elements. Some trace elements, such as As, Hg and Zn, are probably effectively retained in the catchment, whereas Cr tends to be readily exported from the catchment. Atmospheric deposition affected not only elements of anthropogenic origin (As, Ba, Br, Hg, Sb, Zn and Cr) that started to increase after the 1970s, but also those of terrestrial origin (Ca, Fe, Na). Introduction of fish into the lake in 1991 and the subsequent increase in primary production, affected the distribution of Ca and elements that are redox-sensitive and/or associated with OM (As, Ba, Fe, Sb, U, Zn). Fe minerals in uppermost 6J sediments have a strong influence on the distribution of several trace elements. As and Zn closely tracked Fe, whereas Sb was likely released after oxidation. Climate change could also have enhanced inputs of elements from the catchment, but such changes were likely overwhelmed by the effects of increased eutrophication.

This study is focused on the metals’ pollution level in sediment core collected from Manora Picnic Point of Karachi coastal area Pakistan. The sediment was categorized in terms of pH, particle size, total organic carbon (TOC), calcium carbonate, and heavy metals, besides the determining the mineralogy composition of sediment. Metals were determined using proton-induced X-ray emission spectroscopy (PIXE) technique. The results of abundant and heavy metals in the sediment core indicated a significant upward enrichment, which could be the cause of discharge of industrial effluents and domestic wastewaters of Metropolitan Karachi into sea. The average geo-accumulation index values showed that sediments were moderately polluted with Co and Pb, and unpolluted for metals (Al, Ca Mg, Cr, Cu, Fe, K, Mn, Ni, Ti, V, and Zn). The pollution load index values indicate an increasing trend from bottom to top, which may be due to the influence of anthropogenic sources. According to the sediment quality guidelines of United States Environmental Protection Agency (USEPA), core sediment was heavily polluted with Ni and moderately polluted with Pb, Cu and Zn.

Surface sediment samples from Taihu Lake in China and its inflow rivers, along with two lake sediment core samples, were collected and analyzed for organophosphate esters (OPEs). The concentrations of total OPEs varied from 28.60 ng/g to 158.72 ng/g (median: 54.25 ng/g) in river surface sediment and from 62.57 ng/g to 326.84 ng/g (median: 86.37 ng/g) in lake sediment. Tributyl phosphate (TnBP) was the predominant compound in river surface sediment, and tris(2-butoxyethyl) phosphate was predominant in lake sediment. High contamination occurred in the north-west region, which was related to the high level of urbanization and high usage of OPEs. The sediment-water partition coefficients of OPEs (logKoc) were calculated, showing a significant correlation with logKow (p < 0.05). The concentration and composition of OPEs in two sediment cores varied due to the different sampling locations, with more OPE species found in the northern region than in the southern one. Principal component analysis and positive matrix factorization indicated that sewage discharges, vehicle emissions, and atmospheric deposition were the possible sources of OPEs in Taihu Lake sediments. Tris(1-chloro-2-propyl) phosphate, tris(2-chloroethyl) phosphate, and TnBP were the main OPEs causing ecological risks.

Dust storm variations over the past ~230 years were reconstructed on the northeast Loess Plateau using a sediment core from Lake Gonghai. The coarse component of the lake sediments (17.38–109.65 μm) was extracted using the grain size standard deviations method and could be used as a dust storm proxy. The reconstructed results suggest five dust storm peaks: in the 1810s, the late 1850s to the late 1880s, the late 1890s to the early 1920s, ~1950s to the early 1990s, and the late 2000s to the early 2010s. The 1950s–1990s had the highest frequency of dust storms over the past ~230 years, as a result of the combined effects of increased human activities, droughts, and strong winds. Before ~1950, the frequency of dust storms was influenced mainly by natural factors, such as drought events and high intensities of the Siberian High and the East Asian Winter Monsoon. After the 1950s, intensive human activity had a significant impact on dust storms, resulting in a relatively high frequency. However, because of a weakening trend in wind strengths resulting from global warming and ecological rehabilitation projects in North China, the frequency of dust storms has significantly decreased in the past two decades. This study highlights the significant effect of human activities on dust storm generation in Inner Asia and the variations in dust storms under global warming scenarios.

To understand siltation processes within the North Port of Incheon, Korea, this study estimated the sedimentation rate and then determined the dominant mechanisms for the siltation. The sedimentation rate was estimated by comparing bathymetric surveys adjusted with the dredged volume, and verified by the penetration depth of 11 gravity cores to the previous dredging surface. The average sedimentation rate was 64 cm/year but varied from 10 cm/year in the interior to about 100 cm/year at the entrance. To determine the dominant mechanisms for siltation, two ADCPs were deployed at the entrance and the interior end of the harbor over a month to estimate sediment flux. Detailed sediment transport processes were examined by two 13-h CTD profiling surveys near the entrance and interior end of the harbor. High siltation at the entrance is attributable to the influx of high turbidity water, the decrease of current velocity, and the formation of an eddy. Low sedimentation inside the harbor was attained by the slow settling of microflocs of about 20–30 mg/l concentration that are maintained regardless of time and space.

Fine-resolution sampling of pollen, non-pollen palynomorphs and microcharcoal as well as sedimentological data in a 6-m sediment core were used to reconstruct both natural conditions and human impacts in the late fifth and early fourth millennia cal bc in the environs of the Nebelivka megasite in Kirovograd Oblast, Central Ukraine. This 238-ha site, dating to the Middle (or BII) Phase of the Trypillia culture, represents one of the first low-density urban establishments in Europe. Despite what was believed to be a sizable population, local human impacts reconstructed from the multi-proxy palaeo-ecological record were moderate in character. There was no positive evidence to indicate a depositional hiatus in the P1 core and no sign of a major ecological impact at any stage in the high-resolution record. The palaeo-ecological record indicates modest settlement agglomeration with less permanent populations rather than permanent populations of tens of thousands of people.

A radionuclide-dated (210Pb and 137Cs) sediment core collected from Hampstead Pond No. 1, a North London lake, was used to provide novel data on the historical accumulation of microplastic waste in the urban environment. Microplastics were extracted from sediments by sieving and dense-liquid separation. Fibres of anthropogenic origin dominated the assemblage. Microplastics were first identified by microscopy before Raman spectroscopy of selected particles was used to determine the composition of synthetic polymers and dyes. Polystyrene microplastic particles were identified, in addition to synthetic fibres of polyacrylonitrile, polyvinyl chloride and fibres containing synthetic dyes. Concentrations of total microplastics in the sediment samples ranged from detection level to 539 particles per kilogram of dried sediment. Proliferation of microplastics is evident in the core from the late 1950s to the present. Relatively low numbers of particles were found in older sediments, comparable to laboratory blanks, highlighting the difficulty of extending a plastic chronostratigraphy back to the early twentieth century. This study shows that, with optimisation, routine extraction of microplastics from radionuclide-dated lake sediments can add an important temporal perspective to our understanding of microplastics in aquatic systems.

For this study, a 15-m sediment core from the Roman harbor of Ephesus has been dated with the luminescence technique. 14C age estimates from the same and a neighboring core were used for comparing and validating the luminescence dating results via a single aliquot regenerative dose (SAR) protocol: infrared stimulation of polymineral and blue stimulation of quartz. The results reveal new insights into the deposition of the sediments of the Roman harbor from 2000 BC to AD 1500 approximately. Some samples showed incomplete bleaching. The difference between the polymineral and the quartz techniques described the bleaching condition before burial. When both approaches give consistent ages, complete bleaching can be assumed. Consistent ages were further applied to the Bayesian age-depth model and discussed within the archeological context. Based on the Bayesian age-depth model, a high sedimentation rate of ca. 65 mm/year was calculated for the period of ~ 700–400 BC suggesting a fast advance of the delta front. However, other age estimates suggest a fast advance for the period 200 BC to ca. AD 100. This is probably due to incomplete bleaching of the luminescence samples and the use of bulk samples for 14C for this new study. Comparing the results with nearby cores suggests that dredging was conducted in the southern part of the Roman harbor at a depth of ca. 5 m b.s.l.

In order to explore the standing stock and preservation of organic carbon, different forms of compound specific lipids were analyzed, based on a 1.8 m sediment core collected in the northern continental shelf of South China Sea in May, 2016. In the core sediments, 21 species of fatty acids, 6 species of alcohols, 8 species of sterols and phytol were detected. Fatty acids were dominated components with the percent of 67%–91% in the total lipids, in which saturated fatty acid C16:0 accounted for about 50%. The contents of lipid species generally decreased from the sediments at surface to those deep, except alcohols waving in a certain range at the same time. Fatty acids primarily existed in free form, followed by base hydrolytic form, and then acid hydrolytic form. Free alcohols were obviously dominated, while base and acid hydrolytic forms contributed small comparably. Phytol gave a significant priority to base hydrolytic form, while acid hydrolytic form could be neglected. Similar to phytol, sterols mostly presented in base hydrolytic form, and then in free form. The compositions of lipids and their forms suggested that organic carbon basically originated from primary production in upper waters in studying area, and were well preserved in the sediments.

Investigations of 239+240Pu and 238Pu in the surface layer (0–5 cm) of bottom sediment in the Crimean 10 salt lakes from 4 geographical groups were carried out for the first time. The 239+240Pu varied widely between regional geographical groups of lakes as well as within groups too and ranged from 11±4 to 451±43 mBq239+240Pu/kg. The highest levels of 239+240Pu—419±27, 443±24 and 451±43 mBq/kg were observed in the Yevpatoriya (Lake Kyzyl-Yar), the Tarkhankut (Dzharylhach) and the Kerch group (Tobechik), respectively. The lowest values of 239+240Pu were identified in three lakes of the Perekop group and were 20±12, 24±6 and 48±6 mBq/kg. In all lakes 238Pu was an order of magnitude lower than 239+240Pu and varied from 4.8±2.6 to 30.7±5.5 mBq/kg. The 238Pu activity was decay-corrected to 1986. The characteristic ratio of the 238Pu/ 239+240Pu activities in the sediment and percentage of the Chernobyl-derived Pu was calculated. The largest percentages of the Chernobyl-derived Pu were observed in the Evpatoriya group (Lake Sasyk-Sivash)—16.2%±8.26%, the Tarkhankut group (Dzharylhach)—8.4%±2.10% and the Kerch group (Aktash)—10.5%±5.56%. The study of the depth distribution of plutonium in the Lake Kyzyl-Yar bottom sediment core (0–25 cm) was fulfilled. It was shown that 239+240Pu was high enough in all studied layers of bottom sediment, but the highest activity ratio 238Pu/ 239+240Pu (0.062±0.020) was found in the deepest layer of 15–20.5 cm and the percentage of Chernobyl-derived Pu was estimated at 6.8%±2.85% in this layer.

In the present study, the environmental changes over the past 100 years in the Cambe River watershed in Southern Brazil were investigated. For this, a sediment core was collected to examine the distribution of metals, polycyclic aromatic hydrocarbons (PAHs), and ecotoxicological markers. The core corresponds from 1914 to 2012, which was obtained by the decay of 210Pb. Changes in the study area also were examined by: Geoaccumulation index (Igeo) and enrichment factor (EF), sediment quality guidelines (SGQs), and ethoxyresorufin-O-deethylase (EROD) activity in Poeciliopsis lucida hepatocellular carcinoma (PLHC-1) cells line. The Σ16 PAHs ranged from 242.6 to 40,775 ng g−1, with pyrogenic source at the beginning of the core, which likely corresponds to the burning of forests to establish the city and the later use of fossil fuels from 1960 to 2012. In the 1930s, most of metals presented a concentration below the background. After the 1930s, high concentrations can be associated with the intense use of fertilizers (Cd, Cu, Zn, Hg) and increases in urban traffic (Zn and Pb). Igeo showed that the distribution of Cu is considered moderately to strongly polluted, and the EF of Pb was considered as moderately polluted. Statistical analyses showed a strong relation between the presence of the ANP, FLU, PHE, BaP, IND, and Bghi compounds and the induction of EROD activity, and no correlation with heavy metals. A prediction model for the linear regression was obtained between the ANP and BaP concentrations and the EROD activity, with an accuracy of 99%.

In studies of environmental change of the past few centuries, $$^{210}$$ Pb dating is often used to obtain chronologies for sedimentary sequences. One of the most commonly used approaches to estimate the age of material at different depths in a sequence is to assume a constant rate of supply (CRS) or influx of ‘unsupported’ $$^{210}$$ Pb from the atmosphere, together with a constant or varying amount of ‘supported’ $$^{210}$$ Pb. Current $$^{210}$$ Pb dating models do not use a proper statistical framework and provide poor estimates of the uncertainties. Here, we develop a new model for $$^{210}$$ Pb dating, where ages and values of supported and unsupported $$^{210}$$ Pb form part of the parameters. We apply our model to a case study from Canada as well as to some simulated examples. Our model can extend beyond the current CRS approach, deal with asymmetric errors and mix $$^{210}$$ Pb with other types of dating, thus obtaining more robust, realistic and statistically better defined age estimates.

This study focused on dating of a sediment core from the Alvarado Lagoon System, Veracruz, Mexico, calculating the sedimentation rate by using 210Pb to determine the tendency towards pollution by polycyclic aromatic hydrocarbons, organochlorides, the metals Cd, Cr, Cu, Hg, Ni, Pb, and V, and organic matter content. The activity of total Pb and supported Pb in the samples was 83.1 and 29.5 Bq kg−1, respectively, whereas the average estimated sedimentation rate was 0.48 ± 0.09 cm per year−1. The organic matter values exhibited linear behavior throughout the historical profile, with values under 2.5%. Metal concentrations followed the order V > Cr > Ni > Cu > Pb > Hg > Cd. Variations found in Cr, Ni, Pb, and V concentrations are basically due to three meteorological phenomena that hit the region: hurricanes Gladys, Hilda, and Janet in September of 1955. V, Ni, and Hg input comes from anthropogenic and lithogenic sources. The presence of individual polycyclic aromatic hydrocarbons showed no ascending accumulation pattern over time, nor did it show any significant statistical correlation to OM. As for the organochlorine pesticides, 63.61% of the total sum of these compounds were from the ciclodienics family. Concentration of p,p′-DDT was observed only in the earliest profile, from 1929.

We present a new radiochemical procedure for the sequential determination of Sr, Am, Pu, Th and U radionuclides. For the validation, seven IAEA certified reference materials were analyzed for 239Pu, 240Pu, 241Pu, 238U and 232Th isotopes by ICP-MS, 243Am by alpha spectrometry and 90Sr by low level gas proportional counting. The sequential method was then used for determining the radionuclide profiles in one sediment core collected in the River Rhine, near Augst, downstream of the Swiss nuclear power plants.

The historical trend of pollution sources of Pb in Tokyo Bay, Japan was investigated on the basis of Pb isotope ratios in a sediment core. The isotope ratios of anthropogenic Pb decreased gradually with increasing Pb concentration in the 1900s–1970s, suggesting a combination of Pb sources with various isotope ratios. In contrast, the isotope ratios of anthropogenic Pb in the 1980s–2000s showed no significant trend, and corresponded to the Pb isotope ratios in the three principal rivers flowing into the bay. It is probable that river bottom sediments contaminated with Pb are principal sources of anthropogenic Pb in Tokyo Bay.

The spatial distribution of polycyclic aromatic hydrocarbons (PAHs) and their source contributions employing receptor models has been widely reported. However, the temporal distribution of PAH source contributions is less studied. Thus, in this paper, three receptor models including principle component analysis-multiple linear regression (PCA-MLR), positive matrix factorization (PMF), and Unmix were used to PAH source apportionment study in a sediment core from Honghu Lake, China. Sixteen USEPA priority PAHs in 37 sliced sediment layers (1-cm interval) were measured, with the concentrations of ∑16PAH (sum of 16 PAHs) ranging from 93.0 to 431 ng g−1. The source apportionment results derived from three receptor models were similar, with three common sources: mixed sources of biomass burning and coal combustion (31.0–41.4% on average), petroleum combustion (31.8–45.5%), and oil leakage (13.1–21.3%). The PMF model segregated an additional source: domestic coal combustion (contributed 20.9% to the ∑16PAHs). Four aspects including intra-comparison, inter-comparison, source numbers and compositions, and source contributions were considered in comparison study. The results indicated that the PMF model was most reasonable in PAH source apportionment research in this study.

Productivity in the eastern equatorial Pacific is limited by the availability of iron. Geochemical analyses of a 100,000-year-long sediment core suggest that pulses of dust deposition during Heinrich stadials fuelled primary productivity.

To understand the spatial characteristics of the acoustic velocity within sediments in the northern slope of the South China Sea, an ultrasonic technique was employed to measure the vertical and horizontal acoustic velocities of sediment core samples. Combined with the physical and mechanical properties test results of sediments, the relationships between acoustic velocity and physical properties were analyzed. The research results showed that the acoustic velocity presented irregular variations at the same depth among different stations, and that, in general, the acoustic velocities in the vertical direction were greater than those in the horizontal direction. For different sampling stations and different depths, the acoustic velocities showed a great variability; they exhibited large differences and there was almost no relation between the vertical and horizontal velocities. In addition, the results clearly exhibited strong anisotropic characteristic among the acoustic velocities. This variation of acoustic velocity was due to complex changes of physical and mechanical properties of seabed sediments in the study area. The results of the study also showed that there was a large deviation between the measured and the predicted acoustic velocities. The predicted results were calculated by empirical equations using the relationships between single geotechnical parameters and the acoustic velocity. The research results improve the understanding of engineering geological properties of the sediments in the study area.

Sediments are major sinks for organic pollutants and therefore can be used as archives of pollutant history. Methoxylated (MeO-) and hydroxylated (OH-) polybrominated diphenyl ethers (PBDE) are of increasing concern because of their potential toxicity and worldwide distribution. However, there is limited information on these compounds in marine environments. Here we determined the contents of nine MeO-PBDE, ten OH-PBDE and total organic carbon in a sediment core collected from the inner shelf of the East China Sea in 2009. The historical trends of 6-MeO-BDE47, 6-OH-BDE47 and total organic carbon were reconstructed. Our results show that 6-MeO-BDE47 concentrations present no significant trend from 1987 to 2005 and then increase from 2005 to 2008. 6-OH-BDE47 concentrations generally increase slightly from 1987 to the end of the 1990s and then decrease. Comparisons between 6-OH-BDE47 and 6-MeO-BDE47 as well as total organic carbon suggest that 6-OH-BDE47 is mainly from terrigenous inputs.

Vertical distribution of metals (Cu, Zn, Cr, Fe, Mn, Pb, Ni, Cd, and Li) in four sediment core samples (C1, C2, C3, and C4) from Anzali international wetland located southwest of the Caspian Sea was examined. Background concentration of each metal was calculated according to different statistical approaches. The results of multivariate statistical analysis showed that Fe and Mn might have significant role in the fate of Ni and Zn in sediment core samples. Different sediment quality indexes were utilized to assess metal pollution in sediment cores. Moreover, a new sediment quality index named aggregative toxicity index (ATI) based on sediment quality guidelines (SQGs) was developed to assess the degree of metal toxicity in an aggregative manner. The increasing pattern of metal pollution and their toxicity degree in upper layers of core samples indicated increasing effects of anthropogenic sources in the study area.

Using gas-chromatography/mass spectrometry (GC-MS) method dating data (210Pb and 137Cs) and OCPs signatures, the temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was investigated in dated sediment core from Baoxianghe reservoir in Dianchi watershed, Southwest China. The concentrations of total PAHs were in the range of 162.3–762.2 ng g−1 from 1945 to 2013. There showed an obvious increase from 1960s to 2000s. The distributions of PAHs were influenced by local population and Gross Domestic Product (GDP) during the period between1962 and 2004. PAHs sources changed from biomass or domestic coal combustion (before 1980) to liquid fossil fuel combustion (after 1980). Total toxic toxicity equivalents (TEQs) of the carcinogenic PAHs were very low (3.03–28.08 ng g−1).

In order to learn whether it is possible to clarify the history of water pollution and its countermeasure from the fluctuation of chemicals accumulated in the sediment core of the lake, concentrations of linear alkylbenzenesulfonates (LAS) in sediment core samples collected from Lake Teganuma, which was severely polluted by domestic wastewater, were determined. The results were compared with concentrations of LAS in the lake water, waters of two large inflowing rivers, and in sewage from the Lake Teganuma basin. Sediment cores collected in 2003 and 2004 recorded the history of domestic wastewater pollution in the basin during the previous 25–35 years. LAS concentrations in the sediment core drastically decreased after the 1990s, and similar reductions of LAS were observed in the river and lake waters. Large amounts of LAS have still been used in the basin during 1980s to 2017, the drastic decrease of LAS concentrations in both the sediment and the river and lake waters is attributable the expansion of sewer system coverage in the basin since 1981. The effect of lake dredging was also estimated by the changes in surfactant concentrations. Thus, historical changes in not only pollution levels but also social factors can be assessed by determining sediment concentrations of chemicals in daily use such as LAS.

A first quasi-successive paleosecular variation data since ∼5.5 kya, including magnetic inclination and relative geomagnetic field intensity variation were obtained from a 55 m-long sediment core in the Nakdong River delta, southeastern Korean Peninsula. Both magnetic inclination curves and relative paleointensity data showed similar trends with those from Lake Biwa, Japan. They also showed close correlation with continuous global geomagnetic field models. For instance, the present study confirms the existence of archeomagnetic jerks. In addition, the present study supports the evidence of globally high geomagnetic intensity circa 3 kya.

A two-part archaeological and limnological study of the Malian Lakes Region has revealed the high research potential of the region. The exploratory reconnaissance of the Gorbi Valley, on the eastern edge of Lake Fati, identified, mapped and sampled eight new sites. The results of the survey suggest a long duration occupation of the Gorbi Valley, as well as possible connections with the populations of the Inland Niger Delta and southeastern Mauritania. The Lake Fati core represents the first lake sediment core from the western Sahel. This 5.4 m sediment core contains a continuous record of lake mud from 10.43 to 4.66 kyr BP. Analysis of the core reveals that Al and Si abundances are decoupled following a deposition of 16 cm of sand at 4.5 ka BP, with Al decreasing and Si increasing rapidly. This period of sand deposition is significantly younger than that of the transition at 5.5 ka BP recorded in marine cores from ODP site 658, taken off the Mauritanian coast, potentially extending the timeframe in which dune systems were stable and lake systems were at their highstand. While highlighting the need for more localized climate chronologies and archaeological investigations, this study may shed light on circumstances surrounding the initial colonization and further development of the Lakes Region.

High-resolution digital imagery of sediment cores increases researchers’ ability to examine, review, and disseminate complex and meaningful core data. The high cost of commercial core scanning systems currently limits the number of cores that are imaged. Here, we present a simple, inexpensive system that can be built in almost any laboratory environment and used to create complete core images. This system uses a stationary light source and a moving core tray (sledge) which provides for consistent lighting across multiple images. Polarized lens filters and diffuse light are used to minimize glare on the core surface. Our system also repurposes professionally engineered exercise equipment which, provides for precise core and camera movement. Once images are taken, stitching software is used to create the final core image. While there are many stitching programs on the market, none are explicitly aimed at stitching together many images in a single, straight line. We evaluated seven of the most common stitching programs and identified Hugin as the most useful for creating completed core images.

In this study we present quantitative elemental analysis techniques like energy dispersive X-ray fluorescence analysis and instrumental neutron activation analysis to assess the impact of industrial discharge on environment. Two cases are discussed, i.e., (a) enrichment of zinc levels in the soil (1080 ± 76 mg kg−1) and zinc uptake ranging between 628 and 40 mg kg−1 in edible plants and cereals grown in agricultural fields near an active zinc smelter, Rajasthan; (b) depth-wise distribution of Cr, Pb and other metals in the sediment core samples from Sundarban wetland, West Bengal, indicating waste discharge from tanneries and other industries.

The characterization of Pu isotopes in a sediment core collected in the western North Pacific off Fukushima in January 2013 was determined. We compared the results with that of the marine sediments collected from July 2011 to July 2012. Both the 239+240Pu activities and the 240Pu/239Pu atom ratios showed no variation in the marine sediments in the last 2 years since the FDNPP accident. Pu contamination in the marine sediments in the investigated areas still originated from global fallout and the Pacific Proving Ground close-in fallout.

The aim of this study was to determine the level of radionuclide concentration in sediment cores in two different water ecosystems; one closed and one open. Based on this data the changes in these ecosystems were interpreted. Two sediment cores from the Dobczyce reservoir and the Smreczynski Staw Lake were collected and divided into 1 cm thick sub-samples. The samples were air dried and homogenized. The 137Cs and 210Pb (210Pbsup, 210Pbtotal, 210Pbuns) concentrations were measured using gamma and alpha spectrometry. Results showed that the 137Cs concentration in the Dobczyce reservoir is lower than in the Smreczynski Staw Lake. Total 210Pb concentration in the Dobczyce reservoir was around 70 Bq kg−1 and in the Smreczynski Staw Lake was about 500 or 1,200 Bq kg−1 with the decreasing tendency in the sediment core. Sediments are very important constituents of water ecosystems. In spite of the young age of the Dobczyce reservoir, the 137Cs and 210Pb radionuclides were very useful in understanding of the processes which have taken place in these ecosystems. The estimated sedimentation rate indicated such processes as regular sedimentation, mixing of sediments or floods. In the Smreczynski Staw Lake the changes have reflected the changes which took place in the Tatra Mountains.

Relocation of the Yellow River estuary has significant impacts on not only terrestrial environment and human activities, but also sedimentary and ecological environments in coastal seas. The responses of regional geochemical characteristics to the relocation event, however, have not been well studied. In the present study, we performed detailed geochemical elemental analyses of a sediment core from the northern Yellow Sea and studied their geochemical responses to the 1855 AD relocation of the Yellow River estuary. The results show that TOC/TN, Co/Al2O3, Cr/Al2O3, Ni/Al2O3 and Se/Al2O3 ratios all decreased abruptly after 1855 AD, and similar decreases are observed in the sediments of the mud area southwest off the Cheju Island. These abrupt changes are very likely caused by the changes in source materials due to the relocation of the Yellow River estuary from the southern Yellow Sea to the Bohai Sea, which the corresponding decreasing trends caused by the changes in main source materials from those transported by the Liaohe River, the Haihe River and the Luanhe River to those by the Yellow River. Because the events have precise ages recorded in historical archives, these obvious changes in elemental geochemistry of sediments can be used to calibrate age models of related coastal sea sediments.

Atmospheric lead (Pb) pollution during the last century in central Yunnan province, one of the largest non-ferrous metal production centers in China, was reconstructed using sediment cores collected from Fuxian and Qingshui Lakes. Lead concentrations and isotopic ratios ((207)Pb/(206)Pb and (208)Pb/(206)Pb) were measured in sediment cores from both lakes. The operationally defined chemical fractions of Pb in sediment core from Fuxian Lake were determined by the optimized BCR procedure. The chronology of the cores was reconstructed using (210)Pb and (137)Cs dating methods. Similar three-phase variations in isotopic ratios and enrichment factors of Pb were observed in the sediment cores from both lakes. Before the 1950s, the sediment data showed low (207)Pb/(206)Pb and (208)Pb/(206)Pb ratios and enrichment factors (EFs=~1), indicating that the sedimentary Pb was predominantly of lithogenic origin. However, these indices were increased gradually between the 1950s and the mid-1980s, implying an atmospheric Pb deposition. The EFs and isotopic ratios of Pb reached their peak during recent years, indicating aggravating atmospheric Pb pollution. The average anthropogenic Pb fluxes since the mid-1980s were estimated to be 0.032 and 0.053 g m(-2) year(-1) recorded in Fuxian and Qingshui cores, respectively. The anthropogenic Pb was primarily concentrated in the reducible fraction. Combining the results of Pb isotopic compositions and chemical speciations in the sediment cores and in potential sources, we deduced that recent aggravating atmospheric Pb pollution in central Yunnan province should primarily be attributed to regional emissions from non-ferrous metal production industries.

Determining the dynamics of silicon in lakes, one of the essential nutrients for diatoms, is valuable for understanding aquatic environmental problems. The dissolved silicon (DSi) and biogenic silicon (BSi) budgets in Lake Kasumigaura, a shallow eutrophic lake in Japan, during the last three decades were assessed based on the analysis of dated sediment cores and a water quality database. Sediment cores (100 cm long) were taken at the center of Lake Kasumigaura in 2005, 2007, and 2009 and at two other sites in 2007. BSi contents of the dated sediments were determined by wet alkaline digestion. The net sedimentation rates of BSi were defined as the difference between the DSi load from inflowing rivers and the DSi and BSi loads from the outflow of the lake, calculated using DSi concentrations and diatom abundances in the lake from 1980 to 2007 and DSi concentrations of the inflowing rivers during 1994, 2007, and 2009. The gross sedimentation rates of BSi were estimated by multiplying BSi concentrations in lake water by the diatom sinking rate reported by previous studies. Budgetary calculations based on the database showed that 60–70 % of DSi inputs from the inflowing rivers during the 27 years could ultimately be accumulated as diatom frustules in bottom sediments in the lake. The sediment analysis revealed that the amount of BSi accumulated in the lake from 1980 to 2007 was 2.0–2.6 × 1011 g, similar to the amount based on the database of 1.3–2.4 × 1011 g. Although the gross sedimentation rates of BSi likely increased, the net sedimentation rates of BSi decreased significantly from 6–10 × 109 g year−1 in the 1980s to 2–6 × 109 g year−1 in the 2000s, suggesting a fast recycling of BSi in recent years caused by an increase in sediment resuspension and regeneration. The sediment core information and the water quality database can be used for calculating the long-term silicon budgets in Lake Kasumigaura. An increase in the DSi release rates was identified, which is consistent with recent sediment resuspension. Comparing the sediment core information with the database suggests the long-term dissolution of sediment BSi; however, analysis of the BSi content in sediment cores representing a much longer time period is needed to confirm this.

The concentrations of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) were measured in two sediment cores collected from Jiaozhou Bay. The concentrations of PCDD/Fs, dioxin-like PCBs, and PCNs in the cores were in the range of 2.8-26.3, 7.1-82.4 and 3.9-56.4 pg/g dw, respectively. The depth profiles of total concentrations PCDD/Fs and dioxin-like PCBs were similar in the sediment core J37 inside Jiaozhou Bay, but different from those in the sediment core J94 outside the bay, suggesting the different sources. In both cores Tri-CNs and Tetra-CNs were dominant, similar to the PCNs composition of some Halowax technical products. The maximal PCNs contamination occurred in the mid-1970s (outside the Bay) and early-1990s (inside the Bay). An increase of the indicator CN congeners characteristic for thermal source in the top layers of the sediment core inside the bay indicated that the contribution from the municipal solid waste incineration has been more important in recent years.

The objectives of this study were to assess the enrichment, contamination, and ecological risk posed by toxic trace elements in the sediments of the Xi River in the industrialized city of Shenyang, China. Surface sediment and sediment core were collected; analyzed for toxic trace elements; and assessed with an index of geoaccumulation (Igeo), enrichment factor (EF) value, potential ecological risk factor (Er), ecological risk index (RI), and probable effect concentration quotient (PECQ). Elemental concentrations (milligram per kilogram) were 8.5-637.9 for As, 6.5-103.9 for Cd, 12.2-21.9 for Co, 90.6-516.0 for Cr, 258.1-1,791.5 for Cu, 2.6-19.0 for Hg, 70.5-174.5 for Ni, 126.9-1,405.8 for Pb, 3.7-260.0 for Sb, 38.4-100.4 for V, and 503-4,929 for Zn. The Igeo, EF, Er, and PECQ indices showed that the contamination of Cd and Hg was more serious than that of As, Cr, Cu, Ni, Pb, Sb, and Zn, whereas the presence of Co and V might be primarily from natural sources. The Igeo index for Cr and Ni might underestimate the degree of contamination, potentially as a result of high concentrations of these elements in the shale. The RI index was higher than 600, indicating a notably high ecological risk of sediment for the river. The average PECQ for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn ranged from 1.4 to 4.1 for surface sediment and from 5.2 to 9.6 in the sediment cores, indicating a high potential for an adverse biological effect. It was concluded that the sediment in the Xi River was severely contaminated and should be remediated as a hazardous material.

Acquiring continuous and high-resolution natural records in recent 2,000 years is the hot issue in the palaeoclimate research. Recent studies revealed that Li/Ca and Mg/Li ratio of carbonate is a potential tracer of past environmental changes in the oceans, and is seldom applied for palaeoclimate reconstruction in lakes. To make full understanding of the potential of Li/Ca ratios of carbonates in lakes, Li/Ca ratios of monospecific ostracod shell Eucypris inflate with similar size in the lacustrine sediment core from Lake Qinghai, NE Tibetan Plateau have been analysed for the first time. Single species can effectively avoid the interspecies effects. In combination with the sedimentation rate that existed, data derived from 210Pb and 137Cs, downcore variations of Li/Ca ratios of ostracod shells during the past 800 years in Lake Qinghai have been reconstructed successfully. By comparing Li/Ca ratios and temperature inferred from meteorological records and tree ring widths in Dulan and Qilianshan in adjacent regions, Li/Ca ratios of ostracod shells negatively correlate with temperature. Higher temperature corresponds with lower Li/Ca ratios, and vice versa, indicating that Li/Ca ratio of ostracod shells is an effective indicator for temperature variations. Therefore, ongoing in-depth investigation using Li/Ca ratios of carbonates in more lakes to further reveal its palaeotemperature implications would be deserved.

Heavy metal concentrations in surface water and sediments collected from Honghu Lake in Hubei Province, China were analyzed, and ecological risks were evaluated according to the sediment quality guidelines. The results showed that the average concentrations of heavy metals in surface water were ranked as: As>Zn> Cu>Cr>Pb>Ni>Cd>Hg. In comparison with results reported in other rivers and the background values, The Honghu Lake was polluted by As, Cr, Pb, Cu and Ni. Most of metals might be mainly from fertilizers, industrial effluent and domestic wastewater around the lake. Heavy metals concentrations were relatively higher in the inlet area than in other areas. Negative correlations were observed between most heavy metals and pH, while a significant positive correlation was present between Zn, Cd and Pb. In the sediment core, Cu, Zn, Cr and Ni showed a decreasing trend while Cd present an increasing trend. The decrease of As, Cu, Zn, Cr and Ni in the 1990s might due to the flood event in 1998. The analysis of ecological risk assessment based on sediment quality guidelines suggested that heavy metals in most sediments from the Honghu Lake had moderate toxicity, with Cr being the highest priority pollutant.

The present occurrence of 226Ra and 228Ra in marine sediment core and fish from the Exclusive Economic Zone in the east coast of Peninsular Malaysia were studied. Sediment core and biota in respectively was collected using multicorer device and purchased from local fishermen at identified stations during the cruise expedition conducted in 2008. The purpose of this study was to determine and to make available an inventory of activity concentration levels and activity ratio for these radionuclides in this region. The activity concentrations of 226Ra and 228Ra in sediment core and edible part of fish were ranged between 15.9–46.5 and 27.7–87.1 Bq/kg dry wt and; 0.80–2.13 and

The historical trend of heavy metal pollution recorded in sediment cores from Lake Shinji, western Japan, was investigated to evaluate the contribution of increasing long-range transport of heavy metals from the Asian continent in recent years. The concentrations of Cd, Co, Cr, Cu, Ni, Pb, Sb, and Zn and lead isotope ratios were determined for sediment cores collected at two sites in the lake. Among the metals, Cd, Sb, and Zn showed markedly high concentrations since the 1970s. Moreover, a high Pb concentration and less radiogenic lead isotope ratios have been observed since the 1980s in the core from a site close to the mouth of a major river. Air masses from the Asian continent, including China, Russia, and South Korea, have less radiogenic lead isotope ratios than those from Japan. This suggests that the recent increase in Pb concentration in the sediment core is primarily due to the long-range transport of heavy metals from the Asian continent, followed by their deposition in the catchment area of the river. The concentration ratios of Pb/Cd, Pb/Sb, and Pb/Zn of the sediment around 2000 were calculated on the basis of the metal concentrations in excess of those before 1940. They were then compared with the volume-weighted annual average concentration ratios of Pb/Cd, Pb/Sb, and Pb/Zn of rain samples collected on the shore of the lake for 1999–2001. The result showed that the ratios of the former to the latter are 1.0 for Cd, 0.69 for Sb, and 0.31 for Zn. Thus, it is likely that the long-range transport of Cd and Sb from the Asian continent also contributes significantly to the recent increase in the concentrations of these metals in the sediment core from Lake Shinji. For Zn, however, the contribution from the Asian continent was evaluated to be small, suggesting the importance of local sources such as effluent discharges.

We present a design for a piston corer that can take a sediment core up to 1 m long, with an undisturbed sediment–water interface. The coring device possesses a tripod unit and a core-tube unit, the latter comprised of a core tube, a piston with a wire, a drive weight in which the core tube is mounted and a steel rod. The tripod stands on the sediment surface during coring, stabilizing the system and serving as an anchor point for the piston wire. A ball clamp, the critical component of the design, is mounted on top of the tripod. The steel rod runs through the ball clamp and at its lower end, holds the drive weight and the core tube. The ball clamp allows the core tube to slide downward, while the piston is held in a fixed vertical position by the wire connected to the tripod. When the corer is lifted, however, the ball clamp locks. This makes it possible to operate the corer with a single cable, because the piston is not subject to any lifting force when the corer is retrieved. The piston remains in position in the core tube even if the collected sediment core is very short. The piston corer can be deployed from a raft or a boat.

A sediment core (L2) from Larsemann Hills, Antarctica was analyzed for Biogenic Silica (BSi), Sand (%) and Total Organic Carbon (TOC). The 78 cm core length represents the time span of ~8.3 cal ka BP. The values of BSi from the core show prominent high productivity from ~8.3 to ~6 cal ka BP in comparison to less productivity in mid-late Holocene (~6 cal ka BP to recent). Moreover, high sand (%) infers the glacio-fluvial deposition from ~8.3 to ~5 cal ka BP TOC shows little variation through out the core, except in the upper ~10 cm (~4 cal ka BP) part wherein it is comparatively high. The increased TOC in the upper part of the core possibly indicates presence of algal mat due to exposure of the lake to the ice free (glacier free) conditions.

Marine sediment cores were collected from two stations at East Malaysia coastal waters on June 2004. Activity concentrations of 210Pb in sediment core were ranged from 11 Bqkg−1 to 84 Bqkg−1 dry wt. for SR 01 and 4 Bqkg−1 to 66 Bqkg−1 dry wt. for SB 03. Meanwhile, activity concentrations of 226Ra in sediment core were varied significantly depending on the sampling location of SR 01 and SB 03 with ranged 17–26 Bqkg−1 dry wt. and 8–11 Bqkg−1 dry wt., respectively. The activity ratios of 210Pb/226Ra were no significantly different at all sampling stations with an average of 1.78. Refer to the entire results; the activities of 210Pb and 226Ra were higher at station SR 01 than station SB 03, but contrast with ratio of 210Pb/226Ra. The reasons of different 210Pb and 226Ra activity concentration and distribution of their ratios were strictly related to their half lives, environment origin, potential sources and behavior.

Sediment core samples were collected from Hiroshima Bay in the Seto Inland Sea, western Northwest Pacific Ocean, and their 239+240Pu activities and 240Pu/239Pu atom ratios were determined by sector field ICP-MS. The activities of 239+240Pu ranged from 0.556 ± 0.025 to 0.745 ± 0.023 mBq/g. The atom ratios of 240Pu/239Pu were almost constant within the whole depth; the average value was 0.227 ± 0.014. This atom ratio was significantly higher than the mean global fallout ratio of 0.18, proving the presence of close-in fallout Pu that originated from the Pacific Proving Ground (PPG). The water masses exchanges between the Kuroshio Current and the Seto Inland Sea brought the PPG source Pu to this area, then Pu was extensively scavenged into sediment particles supplied by the rivers around the bay. The relative contributions of the global fallout Pu and the PPG close-in fallout Pu were evaluated by the two end-member mixing model. The contribution of the PPG close-in fallout was 38–41% of the total Pu in sediment. The remaining 59–62% was attributed to direct global fallout and the land-origin Pu transported by the rivers around the Hiroshima Bay.

Spheroidal carbonaceous particles (SCPs) are produced by the high-temperature combustion of fossil fuels and emitted in to the atmosphere. The distribution and concentration of SCPs in sediments have been used as a proxy for the distribution of pollutants emitted to the atmosphere. However, the effect on the distribution of SCPs due to industrial activity at nearby industrial cities is yet to be quantified. To clarify the origin of SCPs of ~20 μm in size that are preserved in sediments, we evaluated the abundance, surface morphology, and chemical composition of SCPs in sediment core samples recovered from industrial cities in Japan (Tokyo, Osaka, and Nagasaki) and China (Beijing), with the cities being located at least ~500 km away from each other. Vertical profiles of SCP concentration in sediment cores from the Japanese cities and Beijing are different, reflecting the contrasting industrial histories of the two countries. The SCPs from different cities show contrasting morphological and chemical characteristics, suggesting that ~20 μm SCPs in sediments from the industrial cities could represent the local combustion history in detail, as the influx of local SCPs is dominant at such sites.