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

This book is written as a reference on organic substances in natural waters and as a supplementary text for graduate students in water chemistry. The chapters address five topics: amount, origin, nature, geochemistry, and characterization of organic carbon. Of these topics, the main themes are the amount and nature of dissolved organic carbon in natural waters (mainly fresh water, although seawater is briefly discussed). It is hoped that the reader is familiar with organic chemistry, but it is not necessary. The first part of the book is a general overview of the amount and general nature of dissolved organic carbon. Over the past 10 years there has been an exponential increase in knowledge on organic substances in water, which is the result of money directed toward the research of organic compounds, of new methods of analysis (such as gas chromatography and mass spectrometry), and most importantly, the result of more people working in this field. Because of this exponential increase in knowledge, there is a need to pull together and summarize the data that has accumulated from many disciplines over the last decade.

Organic geochemistry of natural waters

Flocculation of dissolved organic and inorganic matter during the mixing of river water and seawater

The complexation of metals with humic materials in natural waters

Terrestrially derived dissolved organic matter (DOM) impacts the optical properties of coastal seawater and affects carbon cycling on a global scale. We studied sequential long-term photochemical and biological degradation of estuarine dissolved organic matter from the Satilla River, an estuary in the southeastern United States that is dominated by vascular plant-derived organic matter. During photodegradation, dissolved organic carbon (DOC) loss (amounting to 31% of the initial DOC) was much less extensive than colored dissolved organic matter (CDOM) or fluorescent dissolved organic matter (FDOM) loss (50% and 56% of the initial CDOM and FDOM), and analysis of kinetics suggested a reservoir of DOC that was resistant to photodegradation. In contrast, CDOM photodegradation closely followed first-order kinetics over two half-lives with no indication of a nondegradable component. FDOM loss was slightly biased toward fluorophores considered representative of terrestrial humic substances. Additional changes in optical properties included increases in spectral slope and shifts in fluorescence excitation/ emission maxima that were generally consistent with previous observations from field studies of photobleached DOM. Biological degradation of photobleached DOM was more rapid than that of unbleached material, and this net positive effect was evident even for extensively photodegraded material. Bacterial degradation caused shifts in the opposite direction from photochemical degradation for both spectral slope and excitation/emission maxima and thus dampened but did not eliminate changes in optical properties caused by photobleaching.

https://aslopubs.onlinelibrary.wiley.com/doi/epdf/10.4319/lo.2000.45.6.1254

Carbon loss and optical property changes during long‐term photochemical and biological degradation of estuarine dissolved organic matter

Organic and inorganic geochemistry of some coastal plain rivers of the southeastern United States

IN natural waters throughout the world1, iron concentrations are commonly several orders of magnitude greater than the equilibrium solubility of iron hydroxide2. Highly coloured waters (which have relatively high concentrations of organic matter) commonly have even greater iron concentrations. Two of the chemical species postulated to account for this phenomenon are: (1) fine colloidal particles of iron hydroxide (possibly associated with colloidal organic matter) and (2) dissolved complexes of iron with naturally occurring organic substances. While the existence of colloidal iron hydroxide in natural waters is widely accepted3, there is little conclusive evidence for or against the existence of dissolved organic complexes of iron. We wish to present evidence which suggests that dissolved organic matter forms complexes not only with iron but also with aluminium, with competition between Fe and Al for available complexing sites determining the relative abundances of the two metals in natural waters.

Organic complexes of iron and aluminium in natural waters

Clay water diagenesis during burial: how mud becomes gneiss

Miocene of the S.E. United States: A model for chemical sedimentation in a peri-marine environment

The mixing of droplets of different pH and acid-neutralizing capacity that occurs when bulk samples of cloud, fog, and rainwater are collected yields solutions that are not in equilibrium with the atmosphere in which the droplets originally equilibrated. In most instances, bulk solutions are expected to outgas volatile solutes to reestablish equilibrium with the atmosphere, with concomitant changes in solution pH. This mixing-induced gas exchange complicates equilibrium and kinetic modeling of pH-dependent atmospheric processes and limits the use of bulk samples for estimation of atmospheric fluxes of volatile weak acids and bases (SO2(g), NH3(g), etc.). Calculations that attempt to interrelate bulk solution pH, bulk solution S(IV) concentration, and atmospheric SO2(g) partial pressure are shown to be fundamentally incorrect, unless the bulk sample has completely reequilibrated with the same atmosphere in which its component droplets were formed. A theoretical proof and several numerical examples are presented to show that droplet mixing at constant atmospheric partial pressures of soluble gases cannot occur without gas exchange.

Kevin C. Beck

Papers

Organic and inorganic geochemistry of some coastal plain rivers of the southeastern United States

Organic complexes of iron and aluminium in natural waters

Clay water diagenesis during burial: how mud becomes gneiss

Miocene of the S.E. United States: A model for chemical sedimentation in a peri-marine environment

Chemical consequences of mixing atmospheric droplets of varied pH