A primer on sediment-trace element chemistry

Abstract

Preface iii Glossary vi Introduction 1 1.0 Importance of sediments to aquatic trace element chemistry 1.1 Monitoring studies 2 1.2 Suspended versus bed sediments-utility for various types of studies 1.3 Partitioning of trace elements between dissolved and solid phases 4 1.4 Fluvial transport of trace elements by suspended sediments 1.5 Comparison of trace element concentrations in suspended and bottom sediments versus dissolved levels 8 1.6 Effect of suspended sediment concentration on fluvial transport of trace elements 1.7 Historical trace element levels 2.0 Physical and chemical factors affecting sediment-trace element chemistry 2.1 Introduction 2.2 Physical factors 2.2.1 Grain-size ranges and the effect of grain size 2.2.2 Chemical analysis of various grain sizes in bottom sediments 18 2.2.3 Chemical analysis of various grain sizes in suspended sediments 18 2.2.4 Effect of grain size on trace element concentrations in samples collected from the same and different basins 2.2.5 Comparison of samples having similar bulk chemistries but differing grain-size distributions 2.2.6 Effect of grain size on sediment-associated chemical transport at differing discharge rates 2.2.7 Measuring grain-size distributions 2.2.7.1 Differences in grain size distributions induced by using different techniques 2.2.7.2 Differences in grain size distributions induced by sample pretreatment 28 2.2.8 Effect of sediment surface area 2.2.9 Importance of surface area to sediment-trace element concentrations 2.2.10 Measuring surface area 2.3 Chemical factors 2.3.1 Cation exchange capacity 38 2.3.2 Composition significant sedimentary trace element collectors 2.3.2.1 Iron and manganese oxides 2.3.2.2 Organic matter 2.3.2.3 Clay minerals 2.3.3 Introduction to and utility of chemical partitioning 48 2.3.4 Chemical partitioning methods 2.3.4.1 Chemical partitioning-instrumental methods 2.3.4.2 Chemical partitioning ~ partial extraction methods 2.3.4.2.1 Chemical partitioning of suspended sediments by partial extraction 2.3.4.2.2 Chemical partitioning of bottom sediments by partial extraction 58 IV 2.3.4.3 Chemical partitioning by density gradient and mineralogy 60 2.3.4.4 Chemical partitioning using statistical manipulation of data 2.3.4.5 Chemical partitioning using mathematical modelling 2.4 The interrelation and relative importance of selected physical and chemical factors affecting sediment-trace element chemistry 2.4.1 Relative importance of physical and chemical factors to sediment-trace element chemistry 2.4.1.1 The interrelation of grain size and surface area to each other and to sediment-trace element chemistry 2.4.1.2 The interrelation of grain size and geochemical substrate to each other and to sediment-trace element chemistry 2.4.1.3 The interrelation of surface area and geochemical substrate to each other and to sediment-trace element chemistry 2.4.2 The interrelation of grain size, surface area, and geochemical substrate to each other 2.4.3 Predicting sediment-trace element concentrations using physical and chemical factors 3.0 Se...

Contrasting sediment and water chemistry indicates the extent of the hyporheic zone in a polluted river system.

“…Downward seepage pulls fine-grained particles into the bed until they clog pore spaces in the material found in the bottom of the watercourse (Chen et al 2013). The bed sediments of the Biała Przemsza are almost totally composed of sand, and therefore the water-borne sediments infiltrating the bed must be very fine with the finest particles of several micrometers in diameter bearing the highest amounts of metals (Horowitz 1991). A study by Karwan & Saiers (2012) suggests that clay-sized particles and colloids can migrate within the pore space of sediment by stream water filtration in sand.…”

Monitoramento de bacias hidrográficas para identificar fontes de sedimentos em suspensão

“…nos seus compartimentos geoquímicos (concentração associada aos óxidos, estrutura cristalina, total, etc.) (HOROWITZ, 1991 O aumento no potencial de cálculo, disponibilizado pelos modelos multivariados de classificação, gerou a necessidade de procedimentos estatísticos mais rigorosos para selecionar as propriedades traçadoras a serem inseridas no modelo.…”

“…Na terceira etapa, são realizadas as análises químicas dos solos das fontes (HOROWITZ, 1991;WALLING & COLLINS, 2000). Nessa etapa, é determinada a concentração de diversos elementos químicos, no intuito de encontrar aqueles que tenham a capacidade de distinguir as diferentes fontes.…”

“…Recomenda-se que a distribuição granulométrica deva ser realizada por granulômetro automático, em função da maior precisão e pelo maior número de classes. Como os elementos traços estão associados em maior concentração às partículas de tamanho silte e argila (HOROWITZ, 1991), existe a necessidade da aplicação de um fator de correção baseado na porcentagem de material menor que 0,063mm para as amostras de solo e amostras de sedimentos em suspensão. A escolha dos elementos químicos deve ser baseada num conjunto de fatores que considera as possíveis diferenças nas A solução do modelo acima é obtida por um processo iterativo de minimização de uma função objetiva que encontra a melhor proporção de cada fonte para compor uma concentração química semelhante à observada no sedimento em suspensão (Equação 4).…”

Selected heavy metals and other constituents in soil and stormwater runoff at the Interstate 95 interchange near Atlee, Virginia, April 1993-May 1997

“…Because heavy metals commonly are bound to silt, clay, and organic material (Horowitz, 1991), concentrations of both total and dissolved copper, lead, and zinc were analyzed in samples collected from November 1996 through May 1997. The concentration of suspended copper appears to be highly correlated to that of total copper, particularly at high concentrations of copper ( fig.…”