Contamination status and potential release of trace metals in a mangrove forest sediment in Ho Chi Minh City,Vietnam

Can Gio district is located in the coastal area of Ho Chi Minh City, southern Vietnam. Discharge of wastewater from Ho Chi Minh City and neighboring provinces to the rivers of Can Gio has led to concerns about the accumulation of trace metals (As, Cu, Cr, Ni, Pb, and Zn) in the coastal sediments. The main objective of this study was to assess the distribution of As, Cu, Cr, Ni, Pb, and Zn in surface and core sediments and to evaluate the contamination status in relation to local background values, as well as the potential release of these selected trace metals from sediments to the water environment. Sediment characteristization, including determination of fine fraction, pH, organic matter, and major elements (Al, Fe, Ca, K, Mg, and S), was carried out to investigate which parameters affect the trace metal enrichment. Fine fraction and Al contents were found to be the controlling proxies affecting the distribution of trace metals while other sediment characteristics did not show any clear influence on trace metals’ distribution. Although As concentrations in the sediments were much higher compared to its reference value in other areas, the enrichment factor based on local background values suggests minor contamination of this element as well as for Cr, Cu, and Pb. Risk assessment suggested a medium to very high risk of Mn, Zn, and Ni under acidification. Of importance is also that trace metals in sediments were not easily mobilized by organic complexation based on their low extractabilities by ammonium-EDTA extraction.

     

Potentially toxic elements in bottom ash from hazardous waste incinerators: an integrated approach to assess the potential release in relation to solid-phase characteristics

Journal of Material Cycles and Waste Management - Understanding the chemical and mineralogical characteristics of bottom ash (BA) containing Potentially Toxic Elements (PTEs, e.g., As, Cd, Co, Cu,...     

Reagenzienfreie Bestimmung von Quecksilberspuren in Wasserproben

A comprehensive ecological monitoring of hazardous substances is indispensable to preserve our health and environment. Therefore, fast and inexpensive techniques for routine analysis of pollutants are essential. However, in the measuring procedure itself often toxic reagents are used producing hazardous waste. Omitting environmentally hazardous substances in the analysis procedure is an important contribution to a more sustainable and green analytical chemistry. A reagent-free method for ultra-trace (pg to ng?L^-1) mercury determination in water samples was developed and validated. An active nanogold collector integrated in a fully automated flow injection system is the core of this new method. All mercury species dissolved in the water sample are adsorbed and preconcentrated on the nano-structured gold surface of the collector. After rinsing and drying of the collector, the enriched mercury is thermally desorbed and finally measured by atomic fluorescence spectrometry. This method was optimized and validated for the determination of mercury in natural waters. The influence of various water constituents was investigated and only high contents of dissolved organic carbon (DOC) showed interferences of mercury preconcentration due to the strong complexation of mercury by DOC. This restriction can be solved by UV-irradiation, i.?e. reagent-free digestion of DOC rich samples prior to the preconcentration procedure. Mercury concentration of several natural river and sea waters and water from the discharge of a waste water treatment plant were determined with this new analytical method. Accuracy and precision of the method were demonstrated by several recovery experiments in natural water samples (recoveries: 96–102?%) and by analysis of the certified reference material BCR-579 (Mercury in Coastal Sea Water; recovery: 101?±?1?%). With a detection limit of only 80?pg?Hg?L^–1 the proposed method is highly sensitive. Furthermore the method avoids potential contamination of the sample by reagent addition and is due to the reagent-free procedure environment-friendly. Hence this work is an important contribution to sustainable environmental analysis and at the same time improves accurate routine mercury trace analysis.     

Reagenzienfreie Bestimmung von Quecksilberspuren in Wasserproben

Routinef?hige, kostengünstige analytische Messverfahren sind die Grundlage für ein fl?chendeckendes Umweltmonitoring von Schadstoffen und somit für die Sicherung unserer Gesundheit und natürlichen Lebensgrundlagen. Hierbei kann die Analytik zur nachhaltigen Nutzung und zur Schonung unserer Umweltressourcen beitragen, indem auf den Einsatz umweltgef?hrdender Reagenzien verzichtet wird.     

A principle of natural self-organization

The Science of Nature - This paper is the first part of a trilogy, which comprises a detailed study of a special type of functional organization and demonstrates its relevance with respect to the...     

Buchbesprechungen

The Science of Nature -     

Classification of alluvial soils according to their potential environmental risk: a case study for Belgian catchments

Alluvial soils may represent important sinks of contaminants as a result of the deposition of contaminated sediments along the river by overbank flooding or after dredging. Because of the erosion of alluvial deposits or the release of contaminants from sediments, alluvial soils can also be a source of contamination. In this paper, a risk assessment for contaminated (alluvial) soils is presented. The approach, mainly based on physico-chemical soil characteristics, single extractions and leaching tests, is illustrated by means of a case study from four Belgian catchments. The extractions and leaching tests that were used have been validated by European testing programs and can provide valuable information for classifying the potential environmental risks of soils. Irrespective of the location, pH, organic carbon content and 'mobilisable' metal concentrations were the most important factors explaining 'mobile' metal concentrations in the alluvial soils. Additionally, the data of the physico-chemical soil characterization, extractions and leaching tests were combined with local and regional factors to classify the alluvial soils in different categories according to their actual and potential risk for the environment.     

Persistent organochlorine pollutants in human serum of 50-65 years old women in the Flanders Environmental and Health Study (FLEHS). Part 2: Correlations among PCBs,PCDD/PCDFs and the use of predictive markers

In 1999, the FLEHS was set by the Flemish Ministry of Health, Belgium to assess pollutant concentrations and related health effect biomarkers in humans living in Flanders. Concentrations of selected organochlorine pesticides, polychlorinated biphenyls (PCB) and polychlorinated dibenzo-p-dioxins (PCDD) and furans (PCDF) were measured by gas chromatography-mass spectrometry and Chemical-Activated LUciferase gene eXpression (CALUX) bioassay in 47 serum pools of 200 women between 50 and 65 years living in two areas of Flanders. Correlation between TEQ values of different groups of compounds were computed in these pool results and it was found that total toxic equivalencies (TEQs) correlated well with the values of the groups of contributing compounds: mono-ortho PCBs (r = 0.77), non-ortho PCBs (r = 0.65) and PCDD/Fs (r = 0.88). The total TEQ was lower correlated to the CALUX-TEQ (r = 0.57). When calculating associations between those classes of compounds in the two studied regions separately, they were all higher correlated in the urban area compared to the more rural region. High correlation coefficients (r > 0.80) were also calculated between individual compounds and groups of compounds. It was suggested that in this studied background-exposed population, some compounds could be good predictors for a group: e.g. PCB 153 for indicator and total PCBs, PCB 118 for total PCB TEQ, PCB 156 for mono-ortho PCB-TEQs and total TEQ, 2,3,4,7,8-P5CDF for PCDD/F TEQs and total TEQs. This means that in pooled serum samples correlations between persistent organochlorine compounds are as strong as for individual POP measurements observed in earlier studies.