UNEP says Baia Mare suffers on-going cyanide & heavy metal contamination

A United Nations investigation into the cyanide spill at a mine tailings operation in Romania, close to the Hungarian border, has concluded that Romanian officials mis-classified the operation as posing a "regular" risk.

The report also states that the “accident occurred in a region with a number of poorly maintained and operated plants and flotation ponds containing cyanide and/or heavy metals, many of which are leaking continuously. Pollution of surface and groundwater as well as soils due to this leaking or acute accidents is likely to occur and re-occur”.

Because Romanian officials classified the Aurul gold and silver producing plant – a joint venture between Australia’s Esmeralda Exploration (see related story) and Romania’s state mining agency – as a “regular” risk, the UN Environment Programme (UNEP) investigation deemed that the “company was operating in line with Government permits”.

Designating the Aurul operation as a “closed-loop” system was an error, according to UNEP. “The loop was open at two points … which allowed unspecified and unmonitored amounts of cyanide to be routinely lost to air and/or groundwater,” concludes the report’s authors. The large-scale spill, which occurred on 30 January, was the result not just of bad weather, as Esmeralda initially claimed, but also “inherent design deficiencies” and “unforeseen operating conditions,” claims UNEP.

The spill on 20 January resulted in about 100,000m³ of liquid and suspended waste being released, including an estimated 50-100 tonnes of cyanide, as well as heavy metals, particularly copper.

The UNEP investigation confirmed that the cyanide plume “was measurable at the Danube delta four weeks later and 2000km from the spill source”. Acute effects were documented by the UNEP team, including phyto- and zooplankton populations down to zero and fish kills, but it was too early to document chronic effects on biodiversity and human health. The team suggests that assessments of chronic effects should be undertaken.

In addition to continued monitoring of the effects of the spill, the authors of the UNEP report recommend a wholesale risk assessment of the “entire system of remining the old tailings” and that questions should be raised regarding whether a less risky method of extracting ingredients from tailings could be introduced.

Beyond changes to the current practice of remining old tailings, UNEP’s report suggests an inventory of all mining and related industry, including abandoned sites, in the Maramures region of Romania and agreement by the countries in the Tisza river catchment on common baseline indicators for water and sediments quality.

On the question of environmental liability, the report states that an international agreement on compensation for accidents with transboundary impact would be preferable to bilateral or multilateral agreements (see related story).

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