Microplastic Contamination in Waters and Sediments in the Selorejo Reservoir, Malang Regency, East Java

Abstract

Microplastics are small plastic particles under 5 mm in size that have contaminated a lot of ecosystems, both aquatic and on land. The existence of heaps of garbage and the existence of fishing activities around residential areas are some examples of anthropogenic activities that are on the edge and water bodies of the Selorejo Reservoir. This study aims to observe the contamination of various types of microplastics and their abundance in water and sediment samples taken from the Selorejo Reservoir. Sampling was carried out using the selected method (purposive sampling) at five different stations, including the Konto River inlet, Kwayangan River inlet, settlements (blendrang), tourism areas, and reservoir outlets. Each station has 3 transects (as replicates) and about 100 liters of water and 1000 grams of sediment are taken. Destruction of water and sediments uses 30% H2O2 and 30% H2SO4 acid to remove organic components that are still attached and to facilitate observation under a stereo microscope with 400X magnification. Based on the results of an analysis of the abundance of microplastics in the waters of each station, the highest abundance of microplastics was successively found in the Konto river inlet with a total abundance value of 39.27x101 particles/liter, then in the residential part (blendrang) a number of 35.34x101 particles/liter, tourist areas 33.67x101 particles/liter, outlet 30.36x101 particles/liter and Kwayangan river inlet 29.67x101 particles/liter. Meanwhile, the highest total abundance of microplastics found in sediments in the Selorejo Reservoir was found successively in the Konto river inlet with a total abundance value of 3.68 particles/gram, then in the tourist area 2.08 particles/gram, in the Kwayangan river inlet 1.56 particles/gram, in the residential part (blendrang) a number of 1.2 particles/gram and outlets 1.12 particles/gram. Each type of microplastic is then counted based on the amount found. The results of the identification of microplastic contamination in waters and sediments in the Selorejo Reservoir found several types of microplastics, namely fibers, fragments, filaments, and films. The dominating type and color of microplastic is black fiber.