| The alkaline aluminate waste, of which 1000-2000 tonnes are dumped a few times a year off the Belgian coast in the Southern Bight of the North Sea, contains 5.4% NaCl, 1.8% dissolved Al and 7.4% NaOH, in addition to traces of heavy metals and some aniline- and phenol-derivatives. The pH rises locally to 8.5 and the total Al-concentration reaches 120 mg liter<sup>-1</sup> (corresponding to an initial waste dilution factor of only 150) in the 10-m wide track just beyond the discharging barge, but these decay quickly to pH 8.1 and 1 mg liter<sup>-1</sup> in the 30-m wide track, 500m behind the barge. The relation between the waste concentration and seawater pH was studied. The white precipitate that forms immediately in the sea was... |
