ICP Waters > Major Results > heavy metals and POPs

In general, the concentrations of heavy metals in ICP Waters sites not influenced by local pollution sources are low. However, a number of ICP sites have concentrations of heavy metals above the critical limit, based on national (e.g., Swedish) guidelines on assumed effects on aquatic biota. The number of ICP Waters sites does not allow a geographically comprehensive evaluation of heavy metal levels in surface waters in Europe and North America. The results from an ICP Waters assessment of persistent organic pollutants (POPs) in the aquatic environment confirm previous studies indicating that global distillation processes (also called the grasshopper-effect) leads to elevated concentrations of contaminants in fish from arctic and alpine areas. There are very few sites with trend data, but they generally show decreasing levels of legacy POPs (i.e., all POPs covered by the Stockholm Convention and the LRTAP Convention). Levels of some newly studied substances, such as brominated flame retardants (PBDE) and PFOS, are probably rising.