The quality of drinking water in three reservoirs located in southwestern Poland has come under scrutiny in recent years as researchers investigate the impact of anthropogenic activities on water quality and trophic status. A recent study assessing the Dobromierz, Lubachów, and Sosnówka reservoirs found that all three bodies of water are at risk of eutrophication, primarily driven by nutrient runoff from surrounding agricultural areas.
The study, which spanned from 1992 to 2022, utilized two classification methods to evaluate water quality indices and trophic statuses. Researchers discovered that the overall water quality in Dobromierz and Lubachów is moderate, while the Sosnówka reservoir boasts good water quality, underscoring the disparities among these crucial water supplies. The findings are crucial as they inform both local authorities and the public about the ongoing challenges and necessary measures for maintaining safe drinking water.
One of the core issues highlighted by the authors of the article relates to the shift in classification methods due to the implementation of the Water Framework Directive. The new classification criteria, which came into force on January 1, 2022, reduced the number of assessment parameters from 23 to 9, altering how water quality is monitored and evaluated across European waters.
"The modifications in monitoring systems and classification criteria have significant implications for understanding and managing water quality in reservoirs,” wrote the authors. They pointed out that this paradigm shift allows for a more focused examination of essential indicators but could also mask important variations that were captured under the old classification system.
An alarming finding of the study is the high variability of physicochemical parameters observed, particularly concerning NO3–N, BOD5, NH4-N, total organic carbon (TOC), and total nitrogen (TN), which were identified as critical factors deteriorating water quality in the studied reservoirs. For Dobromierz reservoir, the average ecological status was below good due to elevated nitrogen levels attributed to fertilizer runoff. In this watershed, nitrogen from agricultural practices is channeled into water bodies, resulting in poor water quality.
The authors noted that "the main pressure for the Dobromierz reservoir is nitrogen compounds of agricultural origin,” emphasizing the need for improved agricultural practices to mitigate nutrient runoff. Furthermore, they highlighted the fact that only 74.9% of residents in the area are connected to a wastewater system, leaving significant segments of the rural population reliant on unregulated wastewater disposal methods.
In investigating the Lubachów reservoir, which also serves as a drinking and industrial water intake for surrounding towns, researchers recommended systematic monitoring to address the eutrophication pressures stemming from both agricultural runoff and untreated wastewater. Similarly, the Sosnówka reservoir revealed concerning trends regarding organic compound levels as indicated by BOD5 and TOC metrics.
The implications of these findings extend beyond regional water quality; the ecological health of these water reservoirs is essential for safeguarding public health and ensuring sustainable water supplies for the future. The authors argued for the implementation of long-term monitoring initiatives, asserting that "long-term monitoring of water quality indicators in drinking water reservoirs is needed in order to develop adaptive measures to environmental changes in the catchment area.”
While the study provides critical insights into the current state of Polish reservoirs, it also emphasizes the necessity for immediate action to address the environmental pressures facing these vital resources. According to the authors, the alarming rates of nutrient accumulation can lead to harmful algal blooms and threaten drinking water safety, ultimately necessitating extensive water treatment processes.
Continuing this research trajectory could yield further recommendations for preventive actions, such as increasing the prevalence of sustainable agricultural practices and enhancing wastewater treatment infrastructure. Only through proactive measures can the future of Poland's drinking water be secured.
