The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities. Broad interrelationships among these processes and their effects can be discerned by application of principles of chemical thermodynamics. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium, including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the Earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural freshwater. The ways in which solutes are taken up or precipitated and the amounts present in solution are influenced by many environmental factors, especially climate, structure and position of rock strata, and biochemical effects associated with life cycles of plants and animals, both microscopic and macroscopic. Taken together and in application with the further influence of the general circulation of all water in the hydrologic cycle, the chemical principles and environmental factors form a basis for the developing science of natural-water chemistry. Fundamental data used in the determination of water quality are obtained by the chemical analysis of water samples in the laboratory or onsite sensing of chemical properties in the field. Sampling is complicated by changes in the composition of moving water and by the effects of particulate suspended material. Some constituents are unstable and require onsite determination or sample preservation. Most of the constituents determined are reported in gravimetric units, usually milligrams per liter or milliequivalents

Study and Interpretation of the Chemical Characteristics of Natural Water

This paper presents a table of abundances of the elements in the various major units of the Earth's lithic crust with a documentation of the sources and a discussion of the choice of units and data.

Distribution of the Elements in Some Major Units of the Earth's Crust

Calculated loading rates of trace metals into the three environmental compartments demonstrate that human activities now have major impacts on the global and regional cycles of most of the trace elements. There is significant contamination of freshwater resources and an accelerating accumulation of toxic metals in the human food chain.

Quantitative assessment of worldwide contamination of air, water and soils by trace metals

One of the most ubiquitous and long-lasting recent changes to the surface of our planet is the accumulation and fragmentation of plastics. Within just a few decades since mass production of plastic...

/pdf/accumulation-and-fragmentation-of-plastic-debris-in-global-2ayi1pcd8z.pdf

Accumulation and fragmentation of plastic debris in global environments.

Chlorofluoromethanes are being added to the environment in steadily increasing amounts. These compounds are chemically inert and may remain in the atmosphere for 40–150 years, and concentrations can be expected to reach 10 to 30 times present levels. Photodissociation of the Chlorofluoromethanes in the stratosphere produces significant amounts of chlorine atoms, and leads to the destruction of atmospheric ozone.

Stratospheric sink for chlorofluoromethanes: chlorine atomc-atalysed destruction of ozone

Chemistry of Pacific pelagic sediments

The mussel watch - a first step in global marine monitoring.

The distribution of clay minerals in the World Ocean

Session I: Metalloids and the Hydride Generation.- The Determination of the Chemical Species of Some of the "Hydride Elements" (Arsenic, Antimony, Tin, and Germanium) in Sea Water: Methodology and Results.- Antimony Content and Speciation in the Water Column and Interstitial Waters of Saanich Inlet.- Ultratrace Speciation and Biogenesis of Methyltin Transport Species in Estuarine Waters.- The Relationship of the Distribution of Dissolved Selenium IV and VI in Three Oceans to Physical and Biological Processes.- Session II: Arctic Chemistry.- Trace Metals in the Arctic Ocean.- Copper in Sub-Arctic Waters of the Pacific Northwest.- Low Level Determination of Trace Metals in Arctic Sea Water and Snow by Differential Pulse Anodic Stripping Voltammetry.- The Relationship between Distributions of Dissolved Cadmium, Iron, and Aluminium and Hydrography in the Central Arctic Ocean.- Session III: Intercalibration Exercise.- Intercomparison of Seawater Sampling Devices for Trace Metals.- The Analysis of Trace Metals in Biological Reference Materials: A Discussion of the Results of the Intercomparison Studies Conducted by the International Council for the Exploration of the Sea.- An Intercomparison of Sampling Devices and Analytical Techniques Using Sea Water from a CEPEX Enclosure.- Session IV: Estuarine Processes Involving Metals.- Role of Fresh Water/Sea Water Mixing on Trace Metal Adsorption Phenomena.- Effects of Particle Size and Density on the Transport of Metals to the Oceans.- The Effect of Sewage Effluents on the Flocculation of Major and Trace Elements in a Stratified Estuary.- Impoverishment and Decrease of Metallic Elements Associated with Suspended Matter in the Gironde Estuary.- The Significance of the River Input of Chemical Elements to the Ocean.- Session V: Air/Sea Exchange and Coastal Processes Involving Metals.- Air-Sea Exchange of Mercury.- Separation of Copper and Nickel by Low Temperature Processes.- The Fate of Particles and Particle-Reactive Trace Metals in Coastal Waters: Radioisotope Studies in Microcosms.- Trace Metals in a Landlocked Intermittently Anoxic Basin.- Session VI: Ocean Distribution and Analysis.- Thorium Isotope Distributions in the Eastern Equatorial Pacific.- Aspects of the Surface Distributions of Copper, Nickel, Cadmium, and Lead in the North Atlantic and North Pacific.- Mn, Ni, Cu, Zn, and Cd in the Western North Atlantic.- Some Recent Measurements of Trace Metals in Atlantic Ocean Waters.- Determination of the Rare Earth Elements in Sea Water.- The Cycle of Living and Dead Particulate Organic Matter in the Pelagic Environment in Relation to Trace Metals.- Trace Metal Levels in Sea Water from the Skagerrak and the Kattegat.- Mercury Concentrations in the North Atlantic in Relation to Cadmium, Aluminium and Oceanographic Parameters.- Perturbations of the Natural Lead Depth Profile in the Sargasso Sea by Industrial Lead.- Copper, Nickel and Cadmium in the Surface Waters of the Mediterranean.- Accurate and Precise Analysis of Trace Levels of Cu, Cd, Pb, Zn, Fe and Ni in Sea Water by Isotope Dilution Mass Spectrometry.- Session VII: Chemical Speciation.- Studies of the Chemical Forms of Trace Elements in Sea Water Using Radiotracers.- Trace Metals (Fe, Cu, Zn, Cd) in Anoxic Environments.- The Behavior of Trace Metals in Marine Anoxic Waters: Solubilities at the Oxygen-Hydrogen Sulfide Interface.- Variations of Dissolved Organic Copper in Marine Waters.- Trace Metals Speciation in Nearshore Anoxic and Suboxic Pore Waters.- The Contrasting Geochemistry of Manganese and Chromium in the Eastern Tropical Pacific Ocean.- Potentialities and Applications of Voltammetry in Chemical Speciation of Trace Metals in the Sea.- Studies of Cadmium, Copper and Zinc Interactions with Marine Fulvic and Humic Materials in Seawater Using Anodic Stripping Voltammetry.- Chemical Periodicity and the Speciation and Cycling of the Elements.- Potentiometric and Conformational Studies of the Acid-Base Properties of Fulvic Acid from Natural Waters.- Copper Speciation in Marine Waters.- Session VIII: Metals and the Biosphere.- Plankton Compositions and Trace Element Fluxes from the Surface Ocean.- Metals in Seawater as Recorded by Mussels.- Trace Elements and Primary Production: Problems, Effects and Solutions.- Trace Metals and Plankton in the Oceans: Facts and Speculations.- Sensitivity of Natural Bacterial Communities to Additions of Copper and to Cupric Ion Activity: A Bioassay of Copper Complexation in Seawater.- List of Participants.- Index of Authors.

Trace Metals in Sea Water

Analyses for the rare-earth elements in sea water, in a phosphorite, and in a manganese nodule were made by neutron activation and x-ray fluorescence techniques. These marine samples showed a depletion in the heavier rareearth elements, relative to chondritic meteorites, beginning with samarium. Cerium was enriched in the manganese nodule, probably as a result of its oxidation to the 4+ valence state. The ratios of the rare-earth abundances in the two minerals to those of sea water go through a maximum in the vicinity of samarium. The europium concentration, often anomalous in terrestrial minerals, was normal relative to the other rare earths in all of the samples. The sea water showed four times the concentration of rare earths at a depth of 4000 meters as compared with surface values. (auth)

Edward D. Goldberg

Papers

Chemistry of Pacific pelagic sediments

The mussel watch - a first step in global marine monitoring.

The distribution of clay minerals in the World Ocean

Trace Metals in Sea Water

Rare-Earth distributions in the marine environment