The effects of iron and manganese mine watres on stream biota (Case study of ecological risk assessment)
| Authors | |
|---|---|
| Year of publication | 2002 |
| Type | Article in Proceedings |
| Conference | SECOTOX 2002. Book of Astracts, 7th Regional Meeting of the Central and Eastern European Section |
| MU Faculty or unit | |
| Citation | |
| Field | Water pollution and control |
| Keywords | Mine waters; iron; manganese; ecological risk assessment; stream biota |
| Description | Small streams in the area of closing uranium mining in the Czech-Moravian Highlands (Czech Republic) were affected by mine waters with high contents of iron and manganese. These elements have a direct toxic or inhibit effect to the bottom stream biota. After decreasing of contents of metals in water (under 0.2 mg.l-1 Fe and 0.05 mg.l-1 Mn) there is main effect of change of bottom habitats. Bottom of stream is hard incrusted by iron and manganese hydroxides to the dept about 10 - 15 cm. Free surface layer is very thin - only about 1 - 2 cm. Communities of bottom organisms react in firsts seasons on higher contents of metals and now predominantly on changes of habitats. Many species disappeared from affected stretches (about 150 - 250 m long), for example planarids, oligochaets, mayflies Baetis, Ephemerella, blackflies, midges etc. Some populations are very small with not normal distributions of age's steadies (Gammarus fossarum). On the other hand, permanent biota of these stretches was consisting mainly of insect's larvae stoneflies (Nemouridae) and caddisflies (Hydropsychidae). Stoneflies are probably good adapted on higher contents of iron and they have in this stretch good bid of CPOM. Larvae of net spinning caddisflies have good bid of drift of small specimens there, which have not possibility to use deeper and hyporheic zone of creek. The evaluated data were the base of complex ecological risk assessment and management of closing uranium-mining area. |
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