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The impact of chemicals on the environment and human health is a cause of increasing concern. Although many studies continue to be carried out on this subject, most address only individual chemicals or particular groups of chemicals, such as metals or radioactive substances. In this paper, we consider the availability of data and knowledge about potentially harmful chemicals from the national to international scale and suggest a strategy to help prevent chemical pollution or deficiencies damaging global sustainability into the 21st century. The main groups of chemicals considered are: (i) Potentially harmful inorganic elements such as As, Cd, Hg and Pb known to have adverse physiological effects at low levels, and elements and species such as Se, I and NO x that can be essential or harmful depending on their concentration, speciation and bioavailability. Chemical elements such as Ga, In and the PGEs that are increasingly used in the development of new materials, including nanotechnology applications, are also discussed briefly. (ii) Radioactive substances, including naturally occurring radioisotopes, such as 238 U and its decay products 226 Ra and 222 Rn, and processed materials, such as depleted uranium (DU), which affect the environment and human health because of their radiological and chemical toxicity. Data on isotopes from the nuclear industry, such as the relatively short-lived isotopes 137 Cs and 90 Sr, are also discussed, including from accidental releases such as Chernobyl in 1986. Isotopes with longer half-lives such as 243 Am and 240 Pu, which are important in the development of nuclear waste management strategies are also considered. (iii) Persistent organic pollutants (POPs) including many synthetic chemicals such as dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), flame retardants and their metabolites, which are characterised by their persistence, bioaccumulation (lipophilicity) and toxicity (PBT) properties. Other synthetic chemicals such as perfluorooctane sulphonate (PFOS), which have different bioaccumulation properties, are considered briefly.(iv) Human and veterinary pharmaceuticals, of which there is increasing evidence of their presence in the environment. These substances are of particular concern because many are designed to target specific biological receptors and hence can have potentially deleterious effects at exceptionally low concentrations. All these groups of chemicals include endocrine disrupting chemicals (EDCs), capable of disrupting animal and human hormone systems (including sex and thyroid).Geochemical databases such as those prepared by the Forum of European Geological Surveys (FOREGS) and the British Geological Survey (BGS) provide systematic information on levels of inorganic chemicals in the environment. Similarly, airborne radiometric databases provide systematic information on the distribution of radioactive substances. Examples of such data are used to demonstrate how the distribution of chemicals in ...

A speedy and accurate staining procedure for the quantitative determination of the feldspars in rocks and sands of soils is proposed. The minerals are treated, by direct contact, with 48 per cent hydrofluoric acid, and then immersed in a concentrated sodium cobaltinitrite solution which stains the potash feldspars yellow. This treatment is followed by immersion in a buffered hematein solution which stains the plagioclase feldspars purple. The depth of colour on the plagioclase depends upon the position in the isomorphous series. Quartz, gypsum and calcite are not affected by the treatment.The quantity of the potash and plagioclase feldspar present is then easily determined by grain counts under the petrographic microscope.

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The composition of surface waters in the Mackenzie River drainage basin falls into three general groups: (1) rivers entering the Slave‐Mackenzie system from the west which have sum‐of‐constituents 100–200 mg/1 and chloride in the range < 1 mg/1 in their headwaters to 2–5 mg/1 at their mouths; (2) surface waters on the Canadian Shield which have lower sum‐of‐constituents (<100 mg/1) and chloride (<1 mg/1); and (3) the Slave and Mackenzie rivers and the Great Bear and Great Slave lakes, which have sum‐of‐constituents 100—200 mg/1 and chloride 5–10 mg/1. Hydraulic head cross sections with evidence of solution collapse structures and anomalous depositional thicknesses indicate extensive solution of Middle Devonian halite and movement of the resulting brines to discharge areas at the principal Devonian outcrop near the Slave River. Chemical and isotopic analysis of saline springs in the discharge area confirms an origin by solution of halite (and gypsum) by meteoric water.