Last spring the largest cyanide contamination of all times ran along river Tisza and Danube. The contamination originated from a Rumanian non-EU compatible sewage of hazardous wastes, barrow of cyanide gold extraction.

Last year we statistically evaluated the time series of cyanide data from five cross-sections of Upper Tisza. The data were measured via laboratory and test paper measurements. This way we could determine the amount of contamination with a good accuracy. In view of the fact that there are multiple of that 95 tons of cyanide in the sewage of hazardous wastes among circumstances of not much safer conditions, we have to be prepared for the early warning and the continuous follow-up of an accidentally occurring new contamination. For this there is a demand for the construction of an on-line system providing reliable results. To fulfil this demand we compiled a critical analysis of publications of the last decade on cyanide determination. A non-negligible demand on the measuring stations is the flexibility to move with a wave of contamination, while providing continuous information.

During the analysis an important condition was the possibility of the determination of all forms of cyanides, since an essential part of cyanide left the sewage in forms of complex cyanides. We have investigated the perturbing effect of the heavy metals accompanying the cyanides in different quantities.

Since the measurements are to be performed in a reliable way under extreme weather conditions (including measurements under firm ice and above water temperature 25⁰C ) great emphasis was laid on weather resistance. It was an important task the reliable data transfer, durability and law service costs.

The performance characteristics played an important role in our analysis, for the method performance was investigated in this analytical methods such as the selectivity, recovery range, linearity, limit of detection, limit of determination, ruggedness and precision.