Handbook of Techniques for Aquatic Sediments Sampling

Extração seletiva de metais pesados em sedimentos de fundo do Rio Tietê, São Paulo

“…A erosão do solo causada pela construção de prédios e rodovias, bem como o lançamento direto de efluentes industriais e municipais têm propiciado um perfil significativamente diferente daqueles verificados em ambientes naturais não impactados. 2 Nesse contexto, uma atenção especial deve ser dada aos metais pesados, que não são naturalmente degradados, nem mesmo permanentemente fixados pelos sedimentos, podendo assim retornar à coluna d'água através de alterações de suas propriedades físico-químicas, tais como pH e potencial redox. 3 Sob condições operacionais definidas, os métodos analíticos de extração seqüencial têm sido aplicados com a proposta de se avaliar a distribuição dos metais nas diferentes formas que compõem o sedimento, tendo em vista o comportamento, a reatividade e o destino dessas espécies nos ambientes aquáticos.…”

Characterization and evaluation of the impact of feed management on the effluents of Nile tilapia (Oreochromis niloticus) culture

“…Chlorophyll a was determined according to Nush (1980). Suspended solids were determined according to Mudroch and Macknight (1991). Water residence time of the ponds was determined by the register of the input water, and dividing the volume of the ponds by the output water value.…”

Grain size distribution effects on phosphate sorption by fluvial sediment: implications for modelling sediment-phosphate transport

“…Sediment grain size, which may influence the results of such investigations, is often neglected. While there are several approaches to the collection and separation of sediment into various particle size fractions (Mudroch & MacKnight, 1991), few methods permit sample collection and separation without compromising the in situ physical and chemical characteristics of the sample. In this study, sediments were separated into different size fractions by cyclosizing to examine grain size distribution effects on phosphate sorption by fluvial sediment.…”

“…All size fractions were immediately freeze-dried and stored. During freeze-drying most particles of dried sediments remain dispersed, aggregation of particles is minimized and oxidation of various minerals or organic compounds is minimized or eliminated (Mudroch & MacKnight, 1991). While freeze-drying can alter the in situ physical and chemical characteristics of sediment, freeze-dried sediments (Green et al, 1978;Oloya & Logan, 1980;Stone & Mudroch, 1989) and air-dried sediments (Sharpley et al, 1981) have previously been used to model P sorption.…”