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Volume XXII |

Evaluation of water contamination in a crossborder river catchment affected by mining activities (a case study between Republics of Serbia and Bulgaria)

Abstract: The current article aims to evaluate water contamination in the crossborder section of the Timok River in terms of metalloids and heavy metals. Water pollution comes due to the unregulated discharges of untreated effluents from the Bor mining area (Eastern Serbia) and surrounding ore-smelting plants, dressing and processing factories. Input data includes information concerning the values of eight chemical parameters (As, Cd, Cu, Fe, Mn, Ni, Pb, and Zn), measured at one water sampling site from 2015 until 2020. The analysis follows the Environmental Quality Standards (EQS) for priority substances and some other pollutants recommended in Directive 2013/39/EC and their equivalent criteria transposed into Ordinance H-4/2012. The Heavy Metal Pollution Indеx (HPI) to assess the suitability of water resources for various human needs is calculated. Results obtained show the content of Cd, Cu, Fe, Mn, Ni, and Zn does not fulfill the EQS. The contamination with Cd and Cu is the most severe, the highest concentrations exceeding the normatively determined standards by more than 20 times. The HPI achieves scores ranging from 200.58 (2015) up to 1163.65 (2019), indicating “High pollution” and suggesting the water resources are inappropriate for human consumption. This work complements past studies with findings for a recent period.

Volume XXII |

Structure and composition of mangrove vegetation in the Lakkang Delta and Lantebung, Makassar City, South Sulawesi, Indonesia

Abstract: As a type of coastal vegetation, mangroves are valuable, unique, and vulnerable. Mangrove ecosystems have a distinctive vegetation structure, which consists of several characteristics sequentially, such as trees, saplings, poles, and seedlings. This study aims to assess and monitor the structure and composition of mangrove vegetation in Makassar City, South Sulawesi. Field surveys were conducted to measure and monitor mangroves in two different areas, namely coastal areas and small islands. The highest mangrove density is at Station 2, which is 0.59 ind/m2, which is a river area. The station with the lowest density is at Station 1, which has a value of 0.23 ind/m2, which is a coastal area. Avicennia marina, Rhizophora apiculata and Acanthus ilicifolius were found to have the highest importance value index. Location 1 is the least stable because it only has the Avicennia marina mangrove species. Meanwhile, at location 3 (Lakkang Island, a small island), there are variations in the value of each index, although it is still in the low category. This means that in general, each research location has a less stable ecosystem. Furthermore, this study can contribute to conservation, biodiversity assessment, and sustainable mangrove ecosystem management strategies.

Volume XXII |

Assessing potential habitat suitability of vulnerable endemic species: a case study of Diospyros celebica Bakh and Rhyticeros cassidix

Abstract: Diospyros celebica Bakh and Rhyticeros cassidix are known to be associated in several locations in Sulawesi. Both of these species are endemic to Indonesia that live throughout the island of Sulawesi. Species Distribution Modeling using Maximum Entropy (MaxEnt) is considered an alternative way to understand the potential area suitable for a species. Model predictions from MaxEnt for all species have an AUC value of 0.887 and 0.837. Suitable habitat for D. celebica Bakh in Central Sulawesi (Morowali Utara, and The southern coast of Banggai) and South Sulawesi (Luwu Timur, Luwu Utara, Toraja Utara, Barru, Pangkep, Maros, Sidrap, Wajo, Sidenreng Rappang, and Gowa). However, the suitable habitat for D. celebica Bakh and R. cassidix in the association is much smaller. Environmental variables that are considered important that influence the occurrence of D. celebica Bakh are Soil Types, especially soil types Dystric Fluvisols, Eutric Fluvisols, Or-thic Luvisols, Orthic Acrisols, Eutric Cambisols, rainfall, and bio13. While R. cassidix is affected by distance from roads, distance from settlements, and distance from rivers, based on actual data points and habitat predictions. Most of the suitable habitat for D. celebica Bakh and R. cassidix is estimated to be outside the conservation area, but the suitable habitat is estimated in 8 functional status conservation areas. These results can be used by the Government of the Republic of Indonesia, and the Ministry of Environment and Forestry for determination.

Volume XXII |

Solid waste management practices in an indigenous Nigerian city: a case of Alesinloye in Ibadan

Abstract: Solid waste management (SWM) is an essential urban service in every human settlement. Despite its importance, cities globally struggle to guarantee its provision even in developed countries. This study examines SWM practices in Alesinloye, Ibadan, Nigeria. A structured questionnaire prepared with KoboCollect was used to interview 182 households using a convenience sampling technique. Findings revealed that households are predominantly married youth with formal education and largely from the Yoruba ethnic group. It further established that food constitutes the leading solid waste component in households. The food waste, along with other waste materials generated, was disposed of mixed because there is no waste sorting system. The households mainly adopt unhygienic and unsustainable approaches such as disposable polythene bags and open space to store solid waste generated temporarily. The private waste firm was primarily responsible for solid waste collection using door-to-door (kerbside) methods in providing its service. The solid waste collection is mostly executed weekly, and the majority of the households consider it suitable. The households paid users’ charges of between ₦500 ($1.09) and ₦ 2000 ($4.35) monthly, and the variations were attributed to mainly waste quantity. While 75.2% of the households expressed satisfaction with users’ charges on solid waste services, 78.6% were unwilling to pay more for improved services, thus indicating the value placed on environmental quality. Finally, the study recommends the establishment of a SWM system towards zero waste community; the establishment of a waste management committee to serve as environmental stewards; the intensification of public campaigns and awareness of the importance of sustainable SWM, and the resuscitation of the Alesinloye recycling plant.

Volume XXII |

Environmental potential of Aedes Aegypti Mosquitoes for Dengue haemorrhagic fever in Pekanbaru, Indonesia

Abstract: Dengue fever is frequently considered a common fever, and this misconception carries the highest risk of fatality. Dengue haemorrhagic fever is still one of Riau Province’s unsolved diseases. This is one of the reasons why this study is necessary to identify prospective mosquito environmental zones with major significance for understanding epidemic transmission in the Pekanbaru City area. The bivariate statistical approach was employed in this research. The aim is to link environmental physical factors to data on the occurrence of dengue haemorrhagic fever in Pekanbaru City. The area under the curve for the correlation between the environment and the distribution of dengue haemorrhagic fever was 0.76 for the rainfall parameter, with 0.68 for the area under the curve derived from the air humidity parameter. The establishment of six environmental indicators resulted in a weight of evidence value of 10,467 to -35,693 for the mosquito’s environmental potential. Meanwhile, the most favourable potential zone, which encompasses 5,935 ha, accounts for 9.18% of the overall area. Areas with the highest risk of spreading Aedes aegypti mosquitoes were found around the city center, both residential and office areas. The risk of dengue haemorrhagic fever transmission in this zone is higher than in the other three zones. By taking earlier events into account, this knowledge can be one of the early preventions in understanding the environmental structure of the Aedes aegypti mosquito habitat.