10:00 〜 10:15
[AHW28-05] Changes in stream water chemistry over 20 years of monitoring at the EANET site Primorskaya, Far East of Russia
キーワード：environmental chemistry, acidification, trend analysis, monitoring, EANET
Starting from 2005, the continuous monitoring of stream water chemistry has been performed at the Komarovka River, Far East of Russia, at the EANET site Primorskaya. At present, we have an archived 20-year data series on major ion concentrations in surface water of stream from small watershed.
At the Komarovka River, inland aquatic samples are regularly taken five times per year, in accordance with the main phases of its hydrological regime. With such a low sampling frequency, it is problematic to calculate the precise amount of compound discharge fluxes with stream waters, so the most of changes in chemical conditions are monitored based on compound concentrations.
Although trend analysis almost does not show clear significant tendencies overall, some changes can be traced while examining graphs. For sulfates, a period of concentration increase was from 2010 to 2021, but later a decrease of them becomes noticeable after the breaking peak in 2021. In recent years, calcium has stopped following sulfates so closely and continues to have an overall increasing tendency with some alterations. Nitrates reached their highest level around 2018, after which a short period of decreased nitrate concentrations is observed.
At the same time, pH does not seem to follow the main trends of major acidifying agents. pH had a trend to decrease until 2019. After that, some years showed an increase in pH levels. In the last year, the stream water pH seems to return to a decreasing tendency, which goes against the overall decrease of sulfate and nitrate concentrations and the increase of calcium.
In recent years, we have observed a change in trends comparing with those found in previous research. Whether these are outliers related to short-term changes in condition or a new trend should be determined during monitoring in the coming years.
This study was carried out in the framework of the Research Project "Development of methods and technologies for monitoring of environmental pollution under the influence of transboundary pollutants transport (UNECE: EMEP, ICP IM) and acid deposition in East Asia (EANET)". Evaluation of archived data was done under the state research theme FMWS-2024-0009 №1023032700199-9 of the Institute of Geography RAS.
At the Komarovka River, inland aquatic samples are regularly taken five times per year, in accordance with the main phases of its hydrological regime. With such a low sampling frequency, it is problematic to calculate the precise amount of compound discharge fluxes with stream waters, so the most of changes in chemical conditions are monitored based on compound concentrations.
Although trend analysis almost does not show clear significant tendencies overall, some changes can be traced while examining graphs. For sulfates, a period of concentration increase was from 2010 to 2021, but later a decrease of them becomes noticeable after the breaking peak in 2021. In recent years, calcium has stopped following sulfates so closely and continues to have an overall increasing tendency with some alterations. Nitrates reached their highest level around 2018, after which a short period of decreased nitrate concentrations is observed.
At the same time, pH does not seem to follow the main trends of major acidifying agents. pH had a trend to decrease until 2019. After that, some years showed an increase in pH levels. In the last year, the stream water pH seems to return to a decreasing tendency, which goes against the overall decrease of sulfate and nitrate concentrations and the increase of calcium.
In recent years, we have observed a change in trends comparing with those found in previous research. Whether these are outliers related to short-term changes in condition or a new trend should be determined during monitoring in the coming years.
This study was carried out in the framework of the Research Project "Development of methods and technologies for monitoring of environmental pollution under the influence of transboundary pollutants transport (UNECE: EMEP, ICP IM) and acid deposition in East Asia (EANET)". Evaluation of archived data was done under the state research theme FMWS-2024-0009 №1023032700199-9 of the Institute of Geography RAS.