The authors propose a methodology for assessing the sources of microplastic pollution (particles 0.5-5 mm in size), which makes it possible to differentiate coastal recreational areas according to the degree of vulnerability to microplastic accumulation. The methodology takes into account the sources of microplastics coming to the beach directly from vacationers - factors of recreational activities, as well as the influence of factors of the adjacent territory: the type of adjacent territory, saturation with transport infrastructure, etc. An analysis of the results of monitoring the microplastic concentration in beach and bottom sediments of seven beaches of the Sevastopol region with varying degrees of anthropogenic load during 2018–2020, as well as an assessment of the sources of microplastic pollution on these beaches using the proposed methodology, made it possible to differentiate these coastal recreational areas according to the degree of vulnerability to accumulation of microplastic pollution. The most vulnerable are the beaches that are actively visited by tourists and located in close proximity to large blocks of apartment buildings and extensive transport infrastructure (Pesochniy and Omega). The beaches Konstantinovsky and Goryachka (placed close tothe thermal power station), located in the zone of active navigation of ships of various tonnage, are confined to areas of low and moderate pollution. The main stream of vacationers on them are local residents with a high turnover rate. The least vulnerable are the beaches with park areas: Uchkuevka, Solnechny and Zolotoy. The source of microplastic pollution on these beaches is mainly vacationers.

The water quality in the western part of Madura Island is currently faced with a severe threat due to pollution. Therefore, this study aimed to investigate the water quality from Bancaran and Kwanyar estuaries, Madura Island, using the physicochemical approaches. A total of eight physiochemical parameters such as salinity, temperature, pH, DO, CO2, BOD, Pb, and Cd were investigated at three sampling stations of each estuary on 15 June 2022 and 19 December 2022 to identify the potential environmental factors controlling the water quality for effective monitoring and management of these estuaries. The results showed that temperature (25–29.5ºC), pH (7.47–7.8), DO (2.45–4.57 ppm), CO2 (0.5–10.4 ppm), BOD (1.86–9.99 mg.L-1) and Pb (–0.55 to –0.31 mg.L-1) differed significantly (P < 0.01), while salinity (0.2–2.90‰) and Cd (0.02–0.05 mg.L-1) did not exhibit significant differences (P > 0.05). Pearson’s correlation indicated significant positive correlations between salinity and Pb, as well as Cd and Pb. According to the principal component analysis (PCA), salinity and BOD were related to the Kwanyar estuary, while the other parameters were associated with the Bancaran estuary. This preliminary investigation showed a decline in the water quality of these estuaries, specifically from DO measurement. Although low DO levels occur naturally, the continuous occurrence will affect the living organisms in the water that plays an important role in the aquatic environment. Therefore, continuous monitoring of these estuaries is needed to provide better information and for protection as well as sustainable use of water resources.