An ecological risk index for aquatic pollution control.a sedimentological approach

Aquatic chemistry is becoming both a rewarding and substantial area of inquiry and is drawing many prominent scientists to its fold. Its literature has changed from a compilation of compositional tables to studies of the chemical reactions occurring within the aquatic environments. But more than this is the recognition that human society in part is determining the nature of aquatic systems. Since rivers deliver to the world ocean most of its dissolved and particulate components, the interactions of these two sets of waters determine the vitality of our coastal waters. This significant vol ume provides not only an introduction to the dynamics of aquatic chem istries but also identifies those materials that jeopardize the resources of both the marine and fluvial domains. Its very title provides its emphasis but clearly not its breadth in considering natural processes. The book will be of great value to those environmental scientists who are dedicated to keeping the resources of the hydrosphere renewable. As the size of the world population becomes larger in the near future and as the uses of materials and energy show parallel increases, the rivers and oceans must be considered as a resource to accept some of the wastes of society. The ability of these waters and the sediments below them to accommodate wastes must be assessed continually. The key questions relate to the capacities of aqueous systems to carry one or more pollutants."

Metal pollution in the aquatic environment

A sequential extraction method (SEDEX) has been developed to separately quantify five sedimentary P reservoirs: loosely sorbed P; ferric iron-bound P; authigenic carbonate fluorapatite + biogenic apatite + CaCO3-associated P; detrital apatite P; and organic P. The SEDEX method successfully separates two of the main categories of authigenic phosphate phases called upon most often as sedimentary sinks for diagenetically mobilized P: ferric oxyhydroxide-associated P and authigenic carbonate fluorapatite (CFAP). It offers a means for separating authigenic CFAP from detrital apatite of igneous or metamorphic origin. The importance of this distinction is that CFAP represents an oceanic sink for reactive P, whereas detrital apatite does not. In addition, a means for reversing secondary adsorption of P onto residual solid surfaces during extraction has been developed.

Extensive standardization of the SEDEX method for application to marine sediments has been performed with analogs for naturally occurring phosphatic phases.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1992.37.7.1460

Development of a sequential extraction method for different forms of phosphorus in marine sediments

The primary mode of interaction of dissolved phosphate with fluvial inorganic suspended particles is via a reversible two-step sorption process. The first step, adsorption/desorption on surfaces, has fast kinetics (minutes-hours). The second step, solid-state diffusion of adsorbed phosphate from the surface into the interior of particles, has slow kinetics (days-months) and is dependent on the time history of the previous surface sorption and the chemistry of the solid diffusional layer. Natural clay particles with a surficial armoring of reactive iron and aluminum hydroxyoxides resulting from chemical weathering of rocks and soils have a high capacity for absorbing phosphate in the second step and for maintaining low “equilibrium phosphate concentrations” in solution. Extrapolation of laboratory sorption and extraction experiments with natural soils and suspended sediments to the environment suggests that the phosphate concentrations of unperturbed turbid rivers (SPM > 50 mg liter I) are controlled near the dynamic equilibrium phosphate concentration of their particles (EPC, = 0.2-l .5 PM) and that fluvial suspended particles “at equilibrium” contain up to 10 pmol-P g-l that is desorbable. Release of this phosphate from particles entering the sea produces the characteristic shape and magnitude of input profiles of dissolved phosphate observed in unperturbed estuaries. On a global scale, fluvial particulates could transport from 1.4 to 14 x 1O’O mol yr-I of reactive phosphate to the sea, some 2-5 times more than that in the dissolved load alone.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1988.33.4part2.0649

Kinetic control of dissolved phosphate in natural rivers and estuaries: A primer on the phosphate buffer mechanism1

In this article, principles of phosphorus retention and phosphorus release at the sediment-water interface in lakes are reviewed. New results and hypotheses are discussed in relation to older models of phosphorus exchange between sediments and water. The fractional composition of sedimentary phosphorus is discussed as a tool for interpretation of different retention mechanisms. Special emphasis is given to the impact of biological, particularly microbial, processes on phosphorus exchange across the sediment-water interface and to the significance of biologically induced CaCO3 precipitation to phosphorus retention in calcareous lakes.

Exchange of phosphorus across the sediment-water interface

The phosphorus in 48 surficial Lake Erie sediment samples was present in three major forms: phosphorus associated with apatite, nonapatite inorganic phosphorus (NAIP), and organic phosphorus. The a...

Forms of Phosphorus in the Surficial Sediments of Lake Erie

The chemical and physical characteristics of six cores from Lake Erie are described The concentrations of Si, Al, K, Na, and Mg, which represent the major mineral species in the sediment, were uni

Cultural Impact on the Geochemistry of Sediments in Lake Erie

On the basis of extensive echosounding and grab sampling, three major units have been recognized in Lake Erie: till and bedrock, glaciolacustrine clay, and postglacial muds. These units represent t...

R. L. Thomas

Papers

Forms of Phosphorus in the Surficial Sediments of Lake Erie

Cultural Impact on the Geochemistry of Sediments in Lake Erie

Surficial Sediments of Lake Erie

Organochlorine insecticides and PCBs in sediments of Lake St. Clair (1970 and 1974) and Lake Erie (1971)

Organochlorine insecticides and PCB in the sediments of Lake Huron (1969) and Georgian Bay and North Channel (1973)