Traceability of sediment analysis

Abstract

Chemical analysis of sediments provides an efficient tool for water-quality management. A basic sequence of measurements comprises three steps: sampling and sample preparation; grain size as a characteristic sediment feature; and, analytical procedures based on standardized extraction schemes and reference materials. These can be considered as an unbroken chain of comparisons. Further steps are split with regard to specific purposes: sediment-quality assessment, including biological effects; coupling of sediment-quality data with erosion-risk evaluation; chemical changes following resuspension of anoxic sediments; and, modeling of chemical sediment data. In the light of the economic value of these further steps for developing and executing far-reaching management plans, coordinated efforts should be made to improve their traceability (e.g., by organized dissemination of results from on-going research (ageing effects), official documentation of techniques and instruments in a relative new field (erosion effects), extension of standardized extraction schemes (anoxic sediments, capacity-controlling properties), and development of new reference materials (pore water)). #

Distribution and Diversity of Gallionella -Like Neutrophilic Iron Oxidizers in a Tidal Freshwater Marsh

“…Cores for iron extraction were sectioned in the field; those for pore water measurement were processed in the laboratory under an argon atmosphere. During transport, cores and samples were kept at 4°C in the dark until processing in order to minimize chemical changes after sampling (15,30,38). In July and October, three locations were sampled: a nonvegetated site and Scirpus and Phragmites sites.…”

Distribuição, fracionamento e mobilidade de elementos traço em sedimentos superficiais

“…São partes essencial, integral e dinâ-mica das bacias hidrográficas, incluindo estuários e zonas costeiras. Sua origem está associada ao intemperismo e erosão de rochas e solos das porções mais altas da área de drenagem 3 . Os sedimentos apresentam valor ecológico, social e econômico.…”

“…De modo geral, os sedimentos têm uma alta capacidade de reter espécies químicas orgânicas e inorgânicas e menos de 1% das substâncias que atingem um sistema aquático são dissolvidas em água e, conseqüentemente, mais de 99% são estocadas no compartimento sedimentar 6 . Portanto, a análise química de sedimentos fornece uma eficiente ferramenta para o gerenciamento da qualidade hídrica 3 . No entanto, a legislação brasileira, que regulamenta a qualidade desses recursos hídricos, não prevê tais procedimentos (resolução CONAMA N o 357, de 17/03/05).…”

Environmental impact of the Midia Port - Black Sea (Romania), on the coastal sediment quality

“…Sediment chemistry -The survey of the sediment pollutants and the evaluation of the sediment quality are mainly performed to show if the sediments represent either a source or a sink for contaminants, and subsequently, to estimate the contaminating e ects upon the aquatic environmental system [43]. The investigation of the distribution of the heavy metals and organic compounds within the sediment samples aims to explain their dispersion associated with the natural inputs (geological background), and with the anthropogenic activities (e.g., industrial and agricultural works, including also port activities and port-related industrial activity).…”