Distribution of trace elements in the marine sediments along the South China Sea,Malaysia

In order to complete having data base of elemental assessment of the east coast of Peninsular Malaysia marine sediments along the South China Sea coasts, trace elements are analyzed and their distribution in marine sediments is undertaken. The present study is done parallel with pervious study on elemental assessment of heavy metals, rare earth elements and actinides in the marine sediments of the east coast of Peninsular Malaysia. Thirty surface sediment samples were collected in this area, including regions of Kelantan, Terengganu, Pahang, Rompin and Johor Baharu. Multielemental analysis was carried out by instrumental neutron activation analysis and inductively coupled plasma atomic emission spectroscopy. In both cases methodology validation was performed by certified reference material analyses. For the surface elemental distributions the enrichment factor values, average I _geo and mC _d values indicate that the trace elements of the surface sediments are uncontaminated in all sampling stations that are consistent with previous studies results of heavy metals, rare earth elements and actinides.     

Activity concentration of some anthropogenic radionuclides in the surface marine sediments near the Saudi coast of the Arabian (Persian) Gulf

Activity concentrations of some anthropogenic radionuclides (⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239+240Pu and ²⁴¹Am) have been measured in the surface of marine sediments along the Saudi coast of the Arabian (Persian) Gulf. The samples were collected at different locations and water depths. The spatial distribution of the concentrations of the measured radionuclides showed a heterogeneous pattern and is independent of location or water depth. The obtained results are discussed and some conclusions are drawn.     

Geochemical aspects and distribution of long-lived radionuclides in marine sediments from Palomares

The main objective of this paper is to point out problems associated with interpretation of bioassay monitoring in view of the existing biokinetic models. The exposure to thorium in Brazil is given in this paper as an example of the seriousness of the problem.     

Distribution of some natural and anthropogenic radionuclides in Sudanese harbour sediments

The distribution of some natural and anthropogenic radionuclides (²²⁶Ra,²²⁸Ra,²¹⁰Po,⁴⁰K,¹³⁷Cs) in surface marine sediments from the harbours at Port Sudan and Sawakin on the Sudanese coast of the Red Sea has been investigated using α-spectrometry and direct high-resolution γ-spectrometry. The prime ams were to assess the levels of radioactivity and the influence of factors such as dredging and the organic matter content of the sediments on the distribution pattern of the radionuclides. The results have been evaluated and the leves indicate the absence of any possible enhancement by anthropogenic influx from the hinterland. The spatial distribution pattern is more heterogeneous in Sawakin harbour where some parts have recently been dredged and the sludge is removed to maintain the required depth. The data also show an insignificant relationship between the activity concentrations of all the radionuclides and the content of organic matter in the sediments.     

Distribution of radionuclides and elements in Cubatão River sediments

Summary Cubat?o River is located in Santos Basin, S?o Paulo State, Brazil. This region is characterized by the occurrence of estuaries and mangrove. Due to its location, near the coastal line, it is also an important industrial area, where phosphate fertilizer plants, petrol refineries, and chemical and steel industries are present. Such human activities contribute to the enhancement of elemental composition in sediments and, in some cases, also increase the radionuclide concentrations, the so called Technologically Enhanced Natural Occurring Radioactive Materials (TENORM). The contamination of land and sediments by TENORM is of major concern. The activity concentration of U and Th series radionuclides was determined in five sediment samples from Cubat?o River. The activity concentration ratio was also determined. Equilibrium was observed for the ratio ²³⁴U/²³⁸U. The activity ratios of Th/²³⁸U, ²²⁸Ra/²²⁶Ra and ²¹⁰Pb/²²⁶Ra were higher than the unity. In the first two cases, the observed values are due to the higher activity of Th in the sediment and in the last case are probably due to the atmospheric deposition of ²¹⁰Pb.     

Distribution of environmental radionuclides in sediment cores of the Jinheung catchment

Sediment core samples taken from the Jinheung catchment located in the middle of the Korean Peninsula were used to know environmental radionuclide distribution. The grain sizes of the sediment cores were found at depth of about 17 cm suggesting that it might have occurred during a dry period of 1969. The radionuclides, ¹³⁷Cs, ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, ²³⁴U, ²³⁸U, ²²⁸Th, ²³⁰Th, ²³²Th, were analyzed by sector type ICP-MS and gamma-spectrometry. The Cs and Pu distribution changed with the depth, in which the maximum ranged from 14 to 22 cm. This was due to the high activity of the results of nuclear bomb tests in the air from 1960s and showed different distribution pattern on the soil surface. The average activity ratio of ²⁴⁰Pu/²³⁹Pu and ²³⁷Np/²³⁹Pu was 0.173 and 0.45, respectively. These values were similar to the north hemisphere global fallout ratio of ²⁴⁰Pu/²³⁹Pu (0.18) and ²³⁷Np/²³⁹Pu (0.45). The ²³⁷Np/²³⁹Pu ratio showed a higher value than the global fallout ratio above 14 cm depth. The U, Th and their daughter radionuclides kept secular equilibrium in the sediment core because the average activity ratios were nearly 1.     

Radiological characterization and environmental impact in northwestern coast of Egypt

A study of environmental radioactivity along the northwestern coast of Egypt was performed by the Central Laboratory for Environmental Radioactivity Measurements Inter-comparison and Training within the framework of the research project: Radiological Studies/Measurements of Natural and Man-made Radionuclides in the Environment. The present paper contains important conclusions, correlations and interpretations of the environmental measurements. The samples collection and measurements were conducted according to the Egyptian Atomic Energy Authority monitoring plan for locations along the northwestern coast of Egypt and its main tributaries of interest. The specific activities of ²²⁶Ra (²³⁸U series), ²²⁸Ra (²³²Th series), ⁴⁰K and ¹³⁷Cs (Bq/kg dry weight) were measured using gamma-ray spectrometers based on hyper-pure germanium detectors. The absorbed radiation dose rates in air (nGy/h) due to natural radionuclides in shore sediment and radium equivalent activity index (Bq/kg) were calculated. The specific activity ratios of ²²⁸Ra/²²⁶Ra were calculated for evaluation of the geo-chemical behavior of these radionuclides. Samples textures and CaCO₃ and total organic matter contents of sediments were also determined while the pH, major cations and anions such as Na⁺, K⁺, Ca⁺⁺, Mg⁺⁺and Cl^?, SO₄ ^– and HCO₃, respectively were also determined in water samples.     

The distribution and behaviour of artificial radionuclides in sediments of the north Wales coast,U.K.

The distribution of¹³⁴Cs,¹³⁷Cs and²¹⁴Am in surface and core sediments from areas in north Wales has been investigated. Coastal sites show a predominance of Sellafield-derived material for all three radionuclides whereas estuarine sites show an increased proportion of Chemobyl-derived caesium present. By the use of the¹³⁴Cs/¹³⁷Cs ratio, a mean proportion of Chemobyl-derived¹³⁷Cs in surface sediments collected in 1991 fell from 34% at an estuarine site to 11% at a coastal site. In deeper sections of cores representing sedimentation dates near the Chemobyl accident, up to 90% of¹³⁷Cs at the estuarine site and 26% at the coastal site can be attributed to Chemobyl. By using the position of the Chemobyl¹³⁴Cs and¹³⁷Cs peak in the cores, sedimentation rates of 0.7 mm·a^–1 were calculated.     

Distribution and forms of phosphorus in tidal flat sediments of the Yangtze Estuary and coast

The distribution and forms of phosphorus (P) were investigated in the tidal flat sediments of the Yangtze Estuary and coast. The total P contents in surface sediments range from 18.0 to 31.4 μmol·g^-1 along the southern coast. The spatial and temporal distribution of P in tidal flats is closely related to the location and pollution resources, especially in association with the variation of hydrodynamic conditions. Significant variations in the forms of P in different sites were observed. P bonded with Ca(Ca-P) is the dominant mineral form in all surface sediments, organic P(Org-P) is lower. Most P is of unstable form, suggesting that P has larger potential activity. P accumulation is the main behavior process between water and sediment in the coastal environment of the Yangtze Estuary.

     

Distribution and forms of phosphorus in tidal flat sediments of the Yangtze Estuary and coast

The distribution and forms of phosphorus (P) were investigated in the tidal flat sediments of the Yangtze Estuary and coast. The total P contents in surface sediments range from 18.0 to 31.4 μmol · g-1 along the southern coast. The spatial and temporal distribution of P in tidal flats is closely related to the location and pollution resources, especially in association with the variation of hydrodynamic conditions. Significant variations in the forms of P in different sites were observed. P bonded with Ca(Ca-P) is the dominant mineral form in all surface sediments, organic P(Org-P) is lower. Most P is of unstable form, suggesting that P has larger potential activity. P accumulation is the main behavior process between water and sediment in the coastal environment of the Yangtze Estuary.     

Artificial radioactive contamination of sediments along the Romanian sector of the Danube river and the Black Sea coast

The concentrations of⁹⁰Sr,²³⁸Pu,^239,240Pu and²⁴¹Am were determined in 12 sediment samples, collected from the bed of the Romanian sector of the Danube river and the Black Sea coast during 1996–1997. The samples were dissolved using a microwave digestion technique which left the refractory part of the samples undissolved. Part of the samples were also dissolved totally by alkaline fusion. The results obtained after radiochemical separations and measurement of the radionuclides by the two dissolution methods were compared recommending the optimum method. The radioactive contamination of the investigated sector in 1996–1997 is compared with the results obtained for the same locations in 1994–1995 reported in previous papers.     

A review on the dynamics of natural radionuclides along the coastal environs of Kerala,south west coast of India

Journal of Radioanalytical and Nuclear Chemistry - Extensive and systematic investigations have been carried in almost all parts of the world in order to obtain a clear understanding of basic...     

Distribution of natural radionuclides

The distribution of natural nuclides and of the effective specific radioactivity in processing of the sphene concentrate was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 8, 2004, pp. 1237–1240.Original Russian Text Copyright © 2004 by Melnik, Lokshin, Sedneva.     

Official controls for the determination of lipophilic marine biotoxins in mussels farmed along the Adriatic coast of Central Italy

In the present study, 334 samples of mussels (Mytilus galloprovincialis) harvested along the coasts of the Central Adriatic Sea during the years 2020–2021 were analyzed for the presence of lipophilic marine biotoxins according to the European Harmonized Standard Operating Procedure. The results showed that 74 (22%) and 84 (25%) samples were positive to okadaic acid and yessotoxin groups, respectively. Among them, only 11 (3.3%) samples resulted as non-compliant, as they exceeded the maximum limits (160 μg okadaic acid equivalent/kg) established by the Regulation (EC) 853/2004. The method applied in this study was able to detect and quantify lipophilic marine biotoxins concentrations, in order to monitor their presence in molluscs and avoid the risk of consumer exposure.     

Distribution of natural radionuclides and assessment of excess lifetime cancer risk along coastal areas of Varkala in Kerala

Journal of Radioanalytical and Nuclear Chemistry - Some of the coastal parts of Kerala are well reported high background radiation areas (HBRA). Hence, the radiological protection of the population...     

Distribution of total carbohydrates in surface sediments of the Egyptian Mediterranean coast,in relation to some inorganic factors

The interrelation between calcium, magnesium, carbonate, fluoride and total carbohydrates (THCO) distribution was investigated for surface sediments collected from three sectors (A–C) along the Egyptian Mediterranean coast during the summer of 2008. The recent ultrasound-acetic acid technique was used for the simultaneous extraction and hydrolysis of total carbohydrates. Based on the average values, the sandy sediments of sector (C) exhibited the highest THCO levels (163.78 ± 53.28 μg/g). In contrast, the silty sand sediments of sector (A) had the lowest average THCO level (8.56 ± 2.60 μg/g). Linear regression model with one predictor showed that there are significant correlations between total carbohydrates, carbonate and fluoride suggesting the common origin of these components. Neither calcium nor magnesium has correlation with THCO. This study revealed that carbonate is the dominant factor affecting the distribution of carbohydrates in the sediments. The spatial distribution of THCO was not affected by the potential sources of runoff, but varied according to the sediments mineralogy.     

Lognormal distribution of natural radionuclides in freshwater sediments and coal-ash repositories

The distribution of natural radionuclides,⁴⁰K,²²⁶Ra, and²³²Th, in freshwater sediments and in coal-fired power-plant ash repositories has been tested for lognormality. Thereafter, lognormality for natural radionuclide concentration frequency distribution was accepted with a high probability. The lognormal natural radionuclide distribution in sediments and coal-ash indicated single population groups. The anthropogenic modifications of the natural radionuclide concentrations in the environment are indicated. The adsorbed dose rates, in mGy y^–1, in air from gamma field of the natural radionuclides were calculated.     

Combining multivariate analysis and geochemical approaches for assessing heavy metal level in sediments from Sudanese harbors along the Red Sea coast

Multivariate statistical analysis and geochemical approaches were exploited for the assessment of the level of some heavy metals (Mn, Fe, Ni, Cu, Zn and Pb) in sediments from Sudanese harbors along the Red Sea coast. Principal component analysis, as a multivariate statistical analysis approach, was applied to identify contribution sources by heavy metals in sediments. While a single source (crustal) was recorded in the bulk sediments and coarse sediment grains (grain-size 1000-500 µm), two sources (crustal and anthropogenic) were recorded in fine sediment grains (grain-size < 500 µm). Furthermore, enrichment factor (EF), as a geochemical approach, appointed polluted sites by heavy metals in the study area. Based upon a previous study addressed the interpretation of EF values, minor to moderate anthropogenic enrichment were recorded in sediments from some sites in the study area. The main anthropogenic activities that believed to be the major sources of pollution by heavy metals in the study area are discharges from oil refinery, industry, shipping activity and domestic waste. Hierarchical cluster analysis (HCA), as another multivariate statistical analysis approach, was applied for the concentrations of heavy metals in bulk sediments to group sediments according to their mineralogical composition. The output of HCA is that sediments from the Port-Sudan harbor can be divided mainly into three areas — east, west and south. For the Sawakin harbor, no apparent trend for the spatial distribution of heavy metals in sediments was recorded.