On 30 January 2000, a cyanide spill caused by an Australian-Romanian ore-enriching site in the Baia Mare region of Romania led to the pollution of the Szamos and Tisza rivers. The spill first entered the Szamos river in Romania; the polluted water crossed the Romanian-Hungarian border at Csenger, and flowed into the upper Tisza in Hungary; it crossed into Yugoslavia and in that country entered the Danube at the confluence of the two rivers.
The cyanide spill had a serious immediate environmental impact. It resulted in a significant loss of life among fish and other taxonomic groups, and threatened the drinking water supplies of the Hungarian city of Szolnok (pop.160,000); the level of cyanide in the upper Tisza was reported at 100 times that the maximum accepted level in drinking-water. Fortunately, no direct loss of human life was reported. The pollution also affected several protected nature reserves, such as Lake Tisza, which is an important part of Hortobágy National Park – a World Heritage site. The cyanide pollution was also accompanied by a significant increase in the concentration of heavy metals in suspended solid in the water (copper, zinc and lead in particular).
Several NGOs quickly took action. Fourteen NGOs formed the Tisza Platform, and coordinated much of the information and controlling work among themselves. Additionally, each NGO conducted its own monitoring program. As a result, awareness of the continuous threat increased.. At the same time also the water management in Hungary started a thorough monitoring of the propagation of the spill to reduce its consequences. One of the stepping stones towards this goal, an Investigation of the Tisza River (ITR) was launched as a component of the Joint Danube Survey (JDS).

 

Findings of the JDS-ITR Survey

 

The sampling was carried out on board the laboratory ship Argus, which from 28 September 2001 to 9 November 2001 traveled along a 744-kilometer stretch of the Tisza river, from Titel in Yugoslavia to Tiszabecs in Hungary. Concentrations of nutrients were not found to be high. High values were detected in only a few tributaries: ammonium and nitrite nitrogen in the Bega and orthophosphate phosphorus in the Zagyva. These have been attributed to a permanent organic load in these tributaries. Chlorophyll-a was low in the upper Tisza, and higher in the lower stretches of the river. In general, the Tisza and its tributaries can be described as non-nutrient-limiting water bodies.
Inorganic micropollutants were examined in water (low metal presence), suspended solids (the form in which metal presence was at its highest), sediments, and mussel species. Several heavy metals (mainly zinc, then copper and nickel) occurred at increased concentrations in suspended solids and sediments. Mercury, which used to be a characteristic pollutant in the Sajo River, was mainly detected in suspended solids and sediments. It is known to be re-mobilized by mixing-up processes during flooding. Other metals found in high concentrations were cadmium, lead, copper, and zinc.
Of the four polar pesticides surveyed in water in order to estimate the effect of agricultural pesticides, atrazine, simazine, and propazine were found in moderate concentrations above detection levels. Endosulfan was not detected. Selected organochlorine compounds were surveyed in sediments and mussels because they tend to accumulate in the solid phase. These pollutants had moderate mean concentrations, equivalent to those found in the Danube. Phytoplankton and zooplankton were found in relatively low concentrations of species diversity and abundance along the surveyed stretch of the river. Several characteristic macroinvertebrate groups were found in the investigated stretch of the river, which led the scientists to conclude that there was no evidence of cyanide or heavy metal pollution.

 

Conclusions

 

The overall conclusion of the JDS-ITR sampling mission is that no detectable effects of the cyanide were observed in the water, suspended solids, sediments, or biota of the Tisza River. All those taxonomic groups that had been adversely affected immediately after the spill had recovered successfully. However, the levels of certain inorganic and organic micropollutants were significantly high in certain stretches of the river.