Releases and flows of zinc

Zinc has a relatively good resistance against corrosion, and the metal has therefore been widely used as a surface protecting agent, e.g. in alloys with aluminium and as a coating for steel (galvanizing) on buildings and infrastructure elements. Nonetheless, corrosion of zinc-containing materials, exposed to urban atmosphere with its various air pollutants, is an important phenomenon, not least because of the potential environmental impact that the released metal could cause (see e.g. IPCS,...

Permitted trace metal loads to agricultural soils

The existing EU Directive regulating the use of sewage sludge in agriculture (86 278 EEC) stipulates the highest permitted loading rate for trace metals as follows 12 kg copper, 3 kg nickel and 30 kg zinc per ha and year as mean value over a period of 10 years. However, due to increasing concerns, several EU member states have set national limits well below the EU Directive (see Table 4.6). A recent EU initiative (Third Draft to the Working Document on the Revision to the Sewage Sludge...

Toxicity to aquatic organisms in the water column

In recent years, it has - again and again - been recognized that the toxicity, e.g. the acute median lethality, LC50, of a trace metal to a single aquatic species can vary widely between different bioassays. This has become a problem, because results of toxicity tests are often used to establish Water Quality Criteria or as inputs into environmental risk assessments, and with variable toxicity data it is difficult to apply criteria based thereon with any certainty. Therefore, environmental...

Speciation Bioavailability and effects of trace metals in the environment

Assessments of the fate and biological effects of trace metals in the environment based solely on total concentrations of the metals in the various media (water, sediment or soil) is no longer state-of-the-art or scientifically justified. Although water, sediment and soil quality criteria for metals in most countries are still based on the total concentrations, it is now becoming more and more evident also for regulatory authorities that it is the actual metal species that determines mobility,...