The VVD has determined the possible cause of fish death in the Odze and Nereta rivers

In the records of the administrative violation initiated by the SES regarding the fish death in the Nereta and Odze rivers established on 5 June, it was concluded that the fish death occurred due to the volcanic pollution in the rivers. Repeated fish deaths were no longer detected.

In order to be able to implement the necessary measures promptly and to find out the causes of fish death, it is important for the SES to receive information on the detected environmental violation immediately. The SES calls on citizens to report immediately any possible environmental violations. This can be done around the clock by calling the single call center at 26 338 800, Kļaveniece pointed out.

Unfortunately, this time the information on fish deaths was provided to the responsible authorities only a few days after the first cases of fish thirst. Due to the release of volcanic pollution into the rivers and the continuous exchange of water in the water body, at the time the SES received information on fish mortality, the pollution there was probably already drained and only the consequences of the pollution could be identified.

In view of the results of the inspections and analyzes received by the SES, as well as the ambiguous information on the initial stage (time) of fish mortality, the continuous water exchange in watercourses, which facilitates the movement of pollutants and the reduction and dispersion of pollutants. whose actions caused the death of the fish, explained a representative of the SES.

Kļaveniece added that when evaluating the results of surface water testing, an increase of certain indicators was found, which can be assessed as the formation of unfavorable conditions for fish, however, it cannot be considered as direct evidence of the violation that caused the fish death. In general, the test results indicate reduced water quality in the Odze River. Therefore, it is assumed that the death of fish may have been caused by the cumulative effects of several stressors, as confirmed by the opinion of the Scientific Institute for Food Safety, Animal Health and the Environment “BIOR”.

In the administrative violation proceedings, the SES has sent its test results to the State Plant Protection Service (VAAD) and requested to provide information on the findings of the VAAD inspections and test results. Information is currently awaited from VAAD. After receiving it, a decision will be made on the further progress of the proposed administrative violation proceedings, Kļaveniece informed.

As no direct discharge of pollution into the environment was detected in the SES inspection on 6 June, as well as no dead fish were detected upstream of the Odze River estuary in the Nereta River, it was concluded that the pollution initially entered the Odze River.

During the administrative violation proceedings initiated by the SES, several possible causes of fish death were identified. There are large areas of agricultural land on the banks of the Odze River, including crops. When inspecting the areas adjacent to the river, bordering the drainage ditch, used packaging of ammonium fertilizer was found, which indicates possible fertilization works. In view of the above facts, pollution from agricultural activities has been analyzed as one of the possible causes of fish mortality. On the other hand, since the solid water waste landfill “Dziļā Vāda” is located in the Odze river catchment area, the negative impact of the landfill has also been analyzed.

After the fish was found to be dead, the SES asked the VAAD to inspect the agricultural areas adjacent to the Odze River so that the complexes could assess the causes of the fish death. It is known that VAAD continues to check the observance of the conditions of use of plant protection products in four farms, the managed fields of which are located by the Odze and Nereta rivers. At present, the SES has not received information on the results of the VAAD test, as well as information on the presence of substances detected in the samples taken by the VAAD.

In order to determine the quality of surface water, including the concentration of pesticides, on 6 and 8 June the SES took surface water samples in the Nereta and Odze rivers, also in the vicinity of the landfill, which were tested in an accredited laboratory and measured oxygen concentrations in watercourses. Currently available test results do not indicate an increased presence of pesticides.

Even before receiving information on fish mortality in the Odze and Nereta rivers, the SES carried out a planned inspection at the landfill on 4 June. During it, significant discrepancies were identified and administrative violation proceedings were initiated, as well as instructions for elimination of violations were provided. It has been concluded that the discrepancies found during this inspection are not the cause of the volcanic pollution entering the Odze River.