Assessment of Groundwater Quality in Karimunjawa Island, Central Java - Indonesia

• Published in: The Indonesian journal of geography 2021-12, Vol.53 (3)
• Main Authors: Ramdhan, Muhammad, Prihantono, Joko, Yulius, Yulius, Husrin, Semeidi, Gemilang, Wisnu
• Format: Article
• Language: English
• ISSN: 0024-9521; 2354-9114
• DOI: 10.22146/ijg.54349

As a small island and tourist destination, Karimunjawa island needs freshwater to support the tourist activity, particularly to supply drinking water. Unfortunately, freshwater on a small island is obtained from groundwater which is very limited and vulnerable to climate change and anthropogenic activities. Therefore, a groundwater quality assessment in Karimunjawa island is necessary to be conducted to provide an up to date information on the groundwater. Furthermore, assessment of groundwater feasibility for drinking, and the pollutant source determination is important to be conducted. The groundwater quality assessment method was conducted in the Karimunjawa sub-district capital by collecting groundwater samples from 12 dug wells, and two samples from the swamp area to find out its impact on the adjacent groundwater.  Afterward, all water samples were analyzed in the Water Quality Laboratory of Bandung Institute of Technology to obtain the value of Nutrient ( NO3-, NO2-, NH3-N); Heavy Metals (Cu, Fe, and Pb); and Salt (TDS, Cl-, Na+). Then, these obtained parameters were compared with the quality standard of the minister of health regulation of the Republic of Indonesia about water quality standards for drinking water. The result shows that generally nutrient contaminant in the groundwater is low, but some groundwater in residences area was contaminated by ammonia with the range value is 1,706 – 9,564 mg/l. Wastewater from residences that seepage into the groundwater is suspected as the source of the ammonia contamination. The heavy metal in the groundwater was undetected, but almost all samples were contaminated by salt which is indicated by a high value of TDS (500-5,580 mg/l). These salt contaminations are caused by seawater intrusion. Therefore, the groundwater in the Karimunjawa sub-district capital experienced quality degradation and it is not feasible to be consumed as drinking water. Good groundwater management, good waste management, and freshwater reservoir construction is expected to improve groundwater quality and freshwater supply in Karimunjawa Island.