Sustainability and impact aspects of exploitation of marine salt, magnesium and bromine

Among the minerals dissolved in seawater some occur in quite high concentrations. Such is for instance the case for salt (NaCl), magnesium (Mg) and bromine (Br), but also for sulphur (S), calcium (Ca), potassium (K), boron (B) and although in lesser quantities-for iodine (I). Salt, magnesium and bromine from marine origin have been exploited on a large scale; salt from times immemorial, the others since numerous decades. In 2000 close to 15 million ton of salt were extracted from the sea, representing 7% of worldwide total salt production. In the same year marine magnesium production amounted to 1.8 million ton or 51% of total magnesium production. Even better, marine bromine production was 380,000 ton or 70% of total world production. But to what extent are those mineral exploitations sustainable and for how long can such operations continue? In view of the industry's demand for these minerals and the very large share of marine origin the question is both pertinent and answers are urgent. The military demands for these minerals, during World War II, contributed largely to the development of "mining" operations while the expansion of the car industry and the need for a no-knock-gasoline spurred the production of bromine. Equally pressing is the question of the impacts such exploitations exert on the environment, both offshore and in the coastal zone. Last but not least, is the use of those minerals not harmful for the environment in general