This study focused on monitoring phosphorus (P) concentrations in the water of the Ramsar site, Lake Vembanad, with a special focus on the mouths of the river bodies draining into the lake, a known hotspot for eutrophication. Four phosphorus fractions—total reactive phosphorus (TRP), total acid hydrolysable phosphorus (TAHP), total organic phosphorus (TOP), and total phosphorus (TP)—were monitored during the pre-monsoon and post-monsoon seasons. The results revealed high levels of all monitored phosphorus fractions, with an average concentration exceeding 300 ppb P across both seasons, indicating a highly eutrophic state. Notably, TRP, TOP, and TP showed high concentrations in both the pre-monsoon and post-monsoon periods. These data suggest significant phosphorus input into the lake’s surface water, potentially triggering excessive algal growth and threatening the biodiversity of this rich wetland ecosystem.

This FAO summary report also provides estimates of the physical scarcity of freshwater at the global level, where in Central Asia the water deficit is 70 per cent, which may be clearly linked to the effects of climate change and the increase in irrigated land. This article examines the quality of groundwater in the Kazygurt region for agricultural use. The Hygienic Water Classification of the CMC by degree of pollution was determined according to SanPiN 2.1.4.559-96: Moderate Pollution Degree; Pollution Index - 1. The degree of water pollution was determined depending on the values of complex indicators: organoleptic - 1.2; sanitary regime - 1.8; sanitary toxicological - 1.2; epidemiological - 0.5; the overall level of pollution is moderate. The dependence of the position of the watershed on the water flow and the length of the sanitary-protective zone on the time of the promotion of pollution to water wells has been determined, taking into account the slope of natural flow and the porosity of aquifers. As a result of calculations the following recommendations can be made: the position of the watershed point -57 m, the length of the sanitary protection zone - 34 m.

Today, all over the world, an important role in the sustainable provision of high-quality drinking water to the population is played by improving the quality of clean water, increasing the efficiency of water use, and ensuring the safety of both the population and countries. In these studies, experiments have been conducted to develop the design of a membrane apparatus capable of effective desalination of groundwater. According to the results of the study, the dependences of permeability and selectivity on the concentration of substances in water, pressure, and water flow velocity were determined. Based on the conducted experiments and the results obtained, a technological scheme and new results have been developed that can be used for sustainable desalination of groundwater and, accordingly, to ensure safe technology for membrane separation of nitrate, chloride, and sulfate salts, improve water quality, increase water use efficiency, and ensure freshwater reserves. The experimental results of groundwater purification in the developed membrane apparatus contribute to the purification of groundwater for chlorides up to 56%, for nitrates up to 99%, for sulfates up to 62%, and for dry residue up to 82%. The experimental results obtained comply with sanitary and hygienic requirements and are suitable for the sustainable use of groundwater as drinking water. It has been experimentally established that the dependence of the degree of regeneration on the rate of its drying is achieved within 1 hour of regeneration and is 99%.

Phosphorus (P) concentration in rivers and lakes receives greater attention due to its significance in contributing to eutrophication. This study aimed at profiling phosphorus species in Vembanad lake (Ramsar site) and its adjoining rivers. Four phosphorus fractions (total reactive phosphorus (TRP), total acid hydrolysable phosphorus (TAHP), total organic phosphorus (TOP) and total phosphorus (TP)) were monitored according to premonsoon and postmonsoon seasons. Meenachil river mouth is a hotspot for eutrophication with high values of most of the phosphorus fractions. Among the four fractions TRP, TOP and TP were recorded maximum concentration during the premonsoon and postmonsoon seasons. Each fraction of TRP, TAHP, TOP, and TP had an average concentration of more than 300 µgL-1 P throughout two seasons, which is highly eutrophic. The result reveals that the surface water of Vembanad lake is highly polluted with phosphorus input and it may trigger algal growth and consequent destruction of the biodiversity rich wetland system.