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Determination of the 36Cl and 129I massic activities using pyrolysis combined with radiochemical separation (using a Cl-resin) in concrete and graphite samples from decommissioning waste originating from Belgian Reactor 3 and 1 (SCK CEN, Belgium), respectively, is described. Liquid scintillation counting is used for their quantification. The chemical recovery of the procedure was evaluated by determining the stable chlorine with ion chromatography and stable iodine with inductively coupled plasma mass spectrometry. The method was optimized and verified by spiking inactive solid materials. [ABSTRACT FROM AUTHOR]

Synthetic solutions of Rh and Pt at near neutral pH, as well as spiked natural waters are subjected to an ageing effect, which means that over time the speciation of the PGEs will be changed from their original composition due to aquation and hydrolysis, forming various hydroxy and aqua complexes. Due to slow ligand exchange reactions equilibrium speciation may not be rapidly attained. Ageing may affect the reactivity of the PGE solutions towards chelating resins used in the analysis of PGEs by Diffusive Gradients in Thin films (DGT). The aim of the study was therefore to investigate the performance of the chelating resins (Purolite S914 and S920 with thiourea and isothiourea functional groups, and IONQUEST® MPX-317 with a phosphine oxide thiourea functional group) for their applicability as a binding resin for DGT applications for Pt and Rh in natural waters using 17-day aged spiked solutions. Uptake kinetics experiments revealed that the direct uptake of Pt on the resins from aged solutions was fast and quantitative, whereas only 30% of Rh was directly bound on the resin. Likewise, much lower apparent diffusion coefficients were obtained for Rh in aged spiked river water (70% decrease) which can be explained by the formation of Rh(OH)3(s) which is not taken up by the resin gel. The addition of dissolved organic matter results in an increased solubilisation of Rh(OH)3(s) and an increased DGT labile fraction. The formation of Rh(OH)3(s) is less pronounced in seawater. For Pt, no species are formed which are not DGT labile. Thus, DGT accurately measures labile metal species in solution, discriminating labile from inert metal species. [ABSTRACT FROM AUTHOR]

Abstract Concentrations of Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, U, V and Zn were quantified in surface sediments collected from 13 different sampling sites from Cau Hai lagoon in Central Vietnam, and in 8 wild and farmed-fishes involving both pelagic and benthic species. Multivariate analysis shows that these trace elements are mainly associated with lithogenic matter, and are most likely the result of alteration and erosion processes in the lagoon. Enrichment factors and geo-accumulation indices reveal substantial sediment enrichments for both As and Bi with respect to the mean composition in the upper continental crust. As is enriched in the edible portion of fish tissue with values up to 10 times higher than the allowed limits set up by Health Canada. Target hazard quotient and target carcinogenic risk for As were assessed through fish diet and were greater than 1 and 10−4, respectively, indicating potential health risks for fish consumers in Cau Hai lagoon. Highlights • EF and I-geo values indicate that surface sediments are contaminated by As and Bi. • Ecological risk (ER) are ranked as ER As,Cd > ER Pb > ER Ni > ER Cr, Cu, Zn. • Farm fishes are slightly more contaminated by As than wild fishes. • THQ and TR values reflect a potential health risk for regular fish consumers. [ABSTRACT FROM AUTHOR]

The coastal population in East Africa is growing rapidly but sewage treatment and recycling facilities in major cities and towns are poorly developed. Since estuarine mangroves are the main hotspots for pollutants, there is a potential for contaminants to accumulate in edible fauna and threaten public health. This study analysed trace metals in muscle tissues of the giant mud crabs ( Scylla serrata) and the giant tiger prawns ( Penaeus monodon) from the Tanzanian coast, in order to determine the extent of bioaccumulation and public health risks. A total of 180 samples of muscle tissues of S. serrata and 80 of P. monodon were collected from nine sites along the coast. Both species showed high levels of trace metals in the wet season and significant bioaccumulation of As, Cu and Zn. Due to their burrowing and feeding habits, mud crabs were more contaminated compared to tiger prawns sampled from the same sites. Apart from that, the measured levels of Cd, Cr and Pb did not exceed maximum limits for human consumption. Based on the current trend of fish consumption in Tanzania (7.7 kg/person/year), the measured elements (As, Cd, Co, Cu, Mn, Pb and Zn) are not likely to present health risks to shellfish consumers. Nevertheless, potential risks of As and Cu cannot be ruled out if the average per capita consumption is exceeded. This calls for strengthened waste management systems and pollution control measures. [ABSTRACT FROM AUTHOR]

The genetic diversity of giant tiger prawns in relation to trace metals (TMs) pollution was analysed using 159 individuals from eight sites at the Tanzanian coast. The seven microsatellites analysed showed high degree of polymorphism (4–44 alleles). The measured genetic diversity (H o = 0.592 ± 0.047) was comparable to that of populations in the Western Indian Ocean. Apart from that, correlation analysis revealed significant negative associations between genetic diversity and TMs pollution ( p < 0.05), supporting the genetic erosion hypothesis. Limited gene flow was indicated by a significant genetic differentiation (F ST = 0.059, p < 0.05). The Mantel test rejected the isolation-by-distance hypothesis, but revealed that gene flow along the Tanzanian coast is limited by TMs pollution. This suggests that TMs affect larvae settlement and it may account for the measured deficiency of heterozygosity. This calls for strengthened pollution control measures in order to conserve this commercially important species. [ABSTRACT FROM AUTHOR]

Mangroves ecosystems support livelihood and economic activities of coastal communities in the tropics and subtropics. Previous reports have documented the inefficiency of waste treatment facilities in Tanzania to contain trace metals. Therefore, the rapidly expanding coastal population and industrial sector is likely to threaten mangrove ecosystems with metal pollution. This study analysed trace metals in 60 sediment samples and 160 giant tiger prawns from the Tanzanian coast in order to document the distribution of trace metals and to establish if measured levels present a threat to mangrove fauna and are of public health importance. High levels of Cr, Co, Cu, Fe, Mn, Ni, and V was observed in mangroves of river Pangani, Wami, and Rufiji. Multivariate analysis showed that they originate mainly from weathering and erosion in the river catchments. Extreme enrichment of Cd was observed in a mangrove affected by municipal sewage. The distribution of Hg, Pb, and Zn was related with urbanisation and industrial activities along the coast. The metal pollution index was high at Pangani, Saadani, and Rufiji, suggesting that these estuarine mangroves are also affected by human activities in the catchment. Moderate to considerable ecological risks were observed in all sampled mangroves, except for Kilwa Masoko. It was revealed that As, Cd, and Hg present moderate risks to fauna. High levels of Cu, Fe and Zn were observed in prawns but the level of the non-essential Cd, Hg, and Pb did not exceed the maximum allowed levels for human consumption. However, based on the trends of fish consumption in the country, weekly intake of Hg is likely to exceed provisional tolerable weekly intake level, especially in fishing communities. This calls for measures to control Hg emissions and to strengthen sewage and waste treatment in coastal cities and urban centres in the basin of major rivers. [ABSTRACT FROM AUTHOR]

The Diffusive Gradients in Thin films (DGT) technique was used to analyse U, 226 Ra and other trace metals in stream water and soil porewater in a wetland in France impacted by uranium mining. High resolution profiles of metals in soil porewater obtained by DGT could be measured for the first time up to a depth of 75 cm by the construction of a novel DGT holder. In stream water, the DGT technique was compared to speciation carried out by filtration (0.45 μm) and ultrafiltration (UF) (500 kDa/100 kDa/10 kDa) and DGT porewater profiles were compared with piezometer data obtained in a parallel study. An increase in the trace concentrations of dissolved (0.45 μm) and particulate U, 226 Ra, and elements such as Al, Fe, Mn and Ba was observed in the stream water as it passes through the bog as a results of mobilization from the wetland. The porewater results indicate DGT labile metals species to be present in porewater and mobilization of uranium and other elements linked to the presence of enriched clays. In stream water, colloids and particles govern the behavior of U, Al and Fe, whereas Mn, Ba and Ra are essentially transported as truly dissolved metal species with DGT labile concentrations accounting for 100% of the dissolved fraction. The combined approaches of DGT and UF allow us to obtain a better understanding on the biogeochemical processes involved in the retention and mobility of U and 226 Ra in the wetland. [ABSTRACT FROM AUTHOR]

The Diffusive Gradients in Thin Films (DGT) technique using PIWBA resin (The Dow Chemical Company) was developed and validated for the measurement of uranium (U) concentration in natural and uranium mining influenced waters. The U uptake on the PIWBA resin gel was 97.3 ± 0.4% (batch method; V sol = 5 mL; [U] = 20 μg L −1 ; 0.01 M NaNO 3 ; pH = 7.0 ± 0.2). The optimal eluent was found to be HNO 3conc /70 °C with an elution efficiency of 88.9 ± 1.4%. The laboratory DGT investigation demonstrated that the PIWBA resin gel exhibits a very good performance across a wide range of pH (3–9) and ionic strength (0.001–0.7 M NaNO 3 ) at different time intervals. Neither effect of PO 4 3− (up to 1.72 × 10 −4 M), nor of HCO 3 − (up to 8.20 × 10 −3 M) on the quantitative measurement of uranium by DGT- PIWBA method were observed. Only at very high Ca 2+ (2.66 × 10 −4 M), and SO 4 2− (5.55 × 10 −4 M) concentration, the U uptake on DGT- PIWBA was appreciably lessened. In-situ DGT field evaluation was carried out in the vicinity of three former uranium mining sites in France (Loire-Atlantique and Herault departments), which employ different water treatment technologies and have different natural geochemical characteristics. There was a similar or inferior U uptake on DGT-Chelex ® -100 in comparison with the U accumulation on a DGT- PIWBA sampler. Most likely, the performance of Chelex ® -100 was negatively affected by a highly complex matrix of mining waters. The high concentration and identity of co-accumulating analytes, typical for the mining environment, did not have a substantial impact on the quantitative uptake of labile U species on DGT - PIWBA . The use of the polyphenol impregnated anion exchange resin leads to a significant advancement in the application and development of the DGT technique for determination of U in the vicinity of the former uranium mining sites. [ABSTRACT FROM AUTHOR]

A new resin- Diphonix ® in Diffusive Gradients in Thin Films (DGT) technique for the determination of uranium was investigated and compared with previously used binding phases for uranium, Chelex ® -100 and Metsorb™. The DGT gel preparation and the elution procedure were optimized for the new resin. The U uptake on Diphonix ® resin gel was 97.4 ± 1.5% (batch method; [U] = 20 μg L −1 ; 0.01 M NaNO 3 ; pH = 7.0 ± 0.2). The optimal eluent was found to be 1 M 1-hydroxyethane-1, 1-diphosphonic acid (HEDPA) with an elution efficiency of 80 ± 4.2%. Laboratory DGT study on U accumulation using a DGT samplers with Diphonix ® resin showed a very good performance across a wide range of pH (3–9) and ionic strength (0.001–0.7 M NaNO 3 ). Diffusion coefficients of uranium at different pH were determined using both, a diffusion cell and the DGT time-series, demonstrating the necessity of the implementation of the effective diffusion coefficients into U-DGT calculations. Diphonix ® resin gel exhibits greater U capacity than Chelex ® -100 and Metsorb™ binding phase gels (a Diphonix ® gel disc is not saturated, even with loading of 10.5 μmol U). Possible interferences with Ca 2+ (up to 1.33 × 10 −2 M), PO 4 3 − (up to 1.72 × 10 −4 M), SO 4 2 − (up to 4.44 × 10 −3 M) and HCO 3 − (up to 8.20 × 10 −3 M) on U-DGT uptake ([U] = 20 μg L −1 ) were investigated. No effect or minor effect of Ca 2+ , PO 4 3 − , SO 4 2 − , and HCO 3 − on the quantitative measurement of U by Diphonix ® -DGT was observed. The results of this study demonstrated the DGT technique with Diphonix ® resin is a reliable and robust method for the measurement of labile uranium species under laboratory conditions. [ABSTRACT FROM AUTHOR]