Modeling land use impacts on spatial distribution of floating plastic litter in surface water of Southeast Asian archipelago

Plastics are present in many ecosystems including floating in surface water of remote archipelago and this can lead to the increase in plastic litter density. Whereas the spatial model of plastic litter density related to the population inhabits isolated archipelago is still limited. And what are the underlying factors driving the presence of plastic litter is also poorly understood. This study is trying to find the answers of those questions. The study was implemented in Thousand Island archipelago located in North of Java Island, one of populated islands in Southeast Asia. The studied surface water covers an area of 10000 Ha and consists of 10 islands with 3 islands are occupied by settlements and the remaining islands are occupied by vegetation. This study has recorded 3 types of floating macro-litter from water that consist of PET, HDPE, and LDPE litter. The plastic litter was observed concentrated in the east sides of archipelago where the populated islands were located. The spatial models show LDPE litter was distributed in the vast areas in comparison to PET and HDPE litter. Beside land use variables, the model has confirmed that the population density was the main underlying factors contribute to the plastic litter density in Thousand Island archipelago. The model can be applied to estimate PET (AIC = -0.53060) and HDPE (AIC = 18.28828) litter density. While LDPE litter density was influenced by population (AIC = 22.60201) rather than population density factors.