The biosphere and the Earth's critical zone have maintained a dynamic equilibrium for more than 3.5 billion years. Except for solar energy, almost all terrestrial substances necessary for life have been derived from near-surface portions of the land, hydrosphere, and atmosphere. If aggregate biological activities are less than the rate of nutrient supply and/or resource renewal, sustained population growth is possible. Where the replenishment rate of a life-sustaining Earth material is finite, usage may reach a condition of dynamic equilibrium in which biological consumption equals but on average cannot exceed the overall supply. Although large, most natural resources are present in finite abundances; for such commodities, excessive present-day human utilization reduces future availability, and thus the ultimate planetary carrying capacity for civilization. Intensive use of Earth materials has enhanced the quality of life, especially in the developed nations. Still, natural background levels, and Earth processes such as volcanic eruptions, as well as human activities involving agriculture, construction, and the extraction, refining, and transformation of mineral resources have led to harmful side effects involving environmental degradation and public health hazards. Among naturally and anthropogenically induced risks are bioaccessible airborne dusts and gases, soluble pollutants in agricultural, industrial, and residential waters, and toxic chemical species in foods and manufactured products. At appropriate levels of ingestion, many Earth materials are necessary for existence, but underdoses and overdoses have mild to serious consequences for human health and longevity. This overview briefly sketches several natural resource health hazards. Included are volcanic ash + aerosols + gases, mineral dusts, non-volcanic aerosols + nanoparticles, asbestos + fibrous zeolites, arsenic, fluorine, iodine, uranium + thorium + radium + radon + polonium, selenium, mercury, copper, lead, chromium, and cadmium. Also noted are health effects of natural disasters, and an obligatory future sustainable consumption of natural resources. Not treated are the overwhelming adverse effects of malnutrition, lack of potable water, inadequate sanitation, fossil fuel usage, mining, manufacturing, and agricultural pollution, or environmental pathogens, nor are the important impacts of complex mixtures of Earth materials considered. With rise of the worldwide information network, economic globalization, and the industrial thrust of Developing Nations, the achievement of natural resource sustainability has emerged as a strategic imperative. Accompanying increased rates of Earth materials consumption and attendant environmental change, substantially improved, universal public health will require a major global effort, integrating collaborations among geoscientists, medical researchers, and epidemiologists. Governments and NGOs must provide important support of such cooperative efforts, and both health and Earth scientists must cross disciplinary and national boundaries. (C) 2012 Elsevier Ltd. All rights reserved.
