n.d. takarina

The coasts around West Java, Indonesia are prospective fishing grounds due to their commercial fish diversity. The presence of neighboring settlements discharging waste, including microplastics, poses a threat to the estuarine ecosystem. This study aimed to quantify and classify microplastics in the tissues of Mugil cephalus, Eleutheronema tetradactylum, and Scatophagus argus. This study takes place in the estuary of the Blanakan River, Subang Regency, an area renowned for its wide variety of commercially valuable fish. Four fish sampling sites were identified according to the predominant land use, with settlements in the upper reaches, ponds in the central area, and mangrove forests in the lower reaches. Fish samples were taken the gastrointestinal tract, gills and muscle to calculated the microplastic content and identify its shape and size. Raman spectroscopy was applied to verify the polymer of microplastic. Statistical analysis was conducted to evaluate variations in microplastic levels at the individual level across these  fish species. The findings indicated the presence of microplastics in the muscle, gastrointestinal tract, and gills of three commercially caught fish from Blanakan, with the muscle being identified as the edible part and the gastrointestinal tract and gills as the non-edible parts. The microplastics were classified according to shape and size and were found in the following order of abundance: Mugil cephalus, Scatophagus argus, Eleutheronema tetradactylum. Mugil cephalus contained the most microplastics (210.8 particles per individual), with the lowest amount recorded in Eleutheronema tetradactylum (41.9 particles per individual). The tissues of Eleutheronema tetradactylum exhibited varying levels of microplastic contamination, with the highest concentration found in the gastrointestinal tract, followed by the gills and muscles. In contrast, in the tissues of Mugil cephalus and Scatophagus argus, microplastics were found in the following order of abundance from high to low: muscle, gastrointestinal tract, gill. The muscle of Mugil cephalus contained the highest microplastic concentration (28.71 particles per gram wet weight), while the lowest was recorded in the muscle of Eleutheronema tetradactylum (3.42 particles per gram wet weight). Microplastics ranging from 300 to 1000 micrometers in size, in the form of fibers and fragments, were commonly found in fish tissues. Microplastic content is found most abundantly in the gastrointestinal tract and muscle. This indicates that feeding and ingestion play a role in the entry of microplastics into the fish's body. Given that the fish falls under the category of commercial and consumption fish, there is a significant concern regarding environmental pollution caused by microplastics and the potential health hazards linked to its consumption.

Zeolite has been recognized as a potential adsorbent for heavy metals in water. The form of zeolite that is generally available in powder has challenged the use of zeolite in the environment. Embedding powder zeolite in a nonwoven sheet, known as a zeolite-embedded sheet can be an alternative to solve that. Another challenge is that information and models of zeolite-embedded sheet removal efficiency are still limited. The novelty of this study is, first, the development of a zeolite-embedded sheet to remove heavy metals from water, and second, the use of the random forest method to model the heavy metal removal efficiency of a zeolite-embedded sheet in water.

The heavy metals studied were copper, lead and zinc, considering that those are common heavy metals found in water. For developing the zeolite-embedded sheet, the methods include fabrication of the zeolite-embedded sheet using a heating procedure and heavy metals adsorption treatment using the zeolite-embedded sheet. The machine learning analysis to model the heavy metal removal efficiency using zeolite-embedded sheet was performed using the random forest method. The random forest models were then validated using the root mean square error, mean square of residuals, percentage variable explained and graphs depicting out-of-bag error of a random forest.

The results show the heavy metal removal efficiency was 5.51-95.6 percent, 42.71-98.92 percent and 13.39-95.97 percent for copper, lead and zinc, respectively. Heavy metals were reduced to 50 percent at metal concentrations of 10.355 milligram per liter for copper, 171.615 milligram per liter for lead and 4.755 milligram per liter for zinc. Based on the random forest models, the important variables affecting copper removal efficiency using zeolite-embedded sheet were its contents in water, followed by water temperature and potential of hydrogen. Conversely, lead and zinc removal efficiency was influenced mostly by potential of hydrogen. The random forest model also confirms that the high efficiency of heavy metals removal (>60 percent) will be achieved at water potential of hydrogen ranges of 4.94–5.61 and temperatures equal to 29.1 degrees Celsius.

In general, a zeolite-embedded sheet can adsorb diluted heavy metals from water because there are percentages of adsorbed heavy metals. The random forest model is very useful to provide information and determine the threshold of heavy metal contents, water potential of hydrogen and temperature to optimize the heavy metal removal efficiency using a zeolite-embedded sheet and reducing pollutants in the environment.

Tropical coastal ecosystems globally have been affected by land use changes. This condition has caused a discharge of pollutants into the water, affecting marine organisms, including fish. Due to their habitat preferences, fish are prone to elevate heavy metals in their tissue. Considering fish is consumable, heavy metal levels in fish can lead to health risks. One of the common edible fish in Southeast Asia is Pennahia argentata. Although widely consumed, there is limited information on how land use influences heavy metal levels in various tissues of this species and its health risk. Fish is one of the main food sources in this region, indicating this information’s importance. This study aims to elaborate on and differentiate the heavy metal levels in tissues and land use types, including settlement and mangrove areas on the West Java coast of Indonesia. Locations of this study are the Jakarta coast representing anthropogenic influences in the form of settlements and the Subang coast as a site of mangrove covers. This study combined remote sensing and Geographic Information System analysis with heavy metal analysis using inductively coupled plasma and studied heavy metals, including cadmium, copper, and zinc, in fish tissues such as the gill, digestive tract, and muscle. Differences and correlation of heavy metal data in each tissue and location were statistically analyzed using Pearson correlation values (r), Analysis of Variance, and x2-test. The estimated Daily Intake was used to determine the health risk consumption of this species. All levels of heavy metals are below the World Health Organization’s permissible limits. Zinc is consistently high in all tissues and locations, while cadmium is the lowest. The result shows that the digestive tract consistently has the highest heavy metal levels compared to other tissues in both locations. Heavy metal in muscle has the lowest level. Copper and zinc in the muscles of fish living on the settlement coasts were 62.69% and 37.18% higher (P <0.05) than fish inhabiting mangrove coasts. Trace elements in the commercial fish P. argentata were significantly affected by differences in land use. Variations in land use have elevated heavy metal levels in fish tissues. Given the high levels of heavy metals, the digestive tract can be chosen as a specific fish tissue to be used as a bioindicator to monitor cadmium, copper, and zinc, particularly on the West Java coast in Indonesia. Because the Estimated Daily Intake for zinc in Jakarta is high, consuming fish should be done with caution.

The lakeside has an enormous sediment carbon storage potential; however, it is susceptible to various environmental changes and can easily become a source of carbon emissions. Understanding the amount of carbon storage in lakeside sediments and organic matter sources may provide information about the potential of lakeside zones in climate change mitigation, particularly for sustainable lake management. This study aims to estimate sediment organic carbon stock and the sources of organic matter in the Maninjau Lakeside-West Sumatera, Indonesia. Sediment sampling was performed at five research sites, with a depth of 0–100 centimeters. Sediment samples were divided into 4 subsamples: 0–15; 15–30; 30–50; and 50–100 centimeters. Bulk density and total nitrogen content were analyzed, and the percentage of organic carbon was calculated from the loss of ignition. The sediment organic carbon stock was calculated based on the bulk density and organic carbon content. Carbon per nitrogen ratio was also calculated to determine temporal changes in the sources of organic matter in the lake. This study demonstrated that Maninjau Lakeside has an enormous potential sedimentary organic carbon stock range between 284.23–442.59 megagrams per carbon per hectare. The highest total sediment carbon stock was found in Duo Koto (442.59 megagrams per carbon per hectare), with the lowest in Koto Kaciak (284.23 megagrams per carbon per hectare). In addition, the study’s results also exhibited significant differences in sediment organic carbon stocks at each location with different land use and cover; in this case, the forest area has a higher carbon stock value than the agricultural and settlement areas. Therefore, it is essential to take initiatives for the restoration and conservation of lakeside areas because of their essential role in mitigating the climate change. The mean ratio of organic carbon and total nitrogen was between 9.96 to 16.91, indicating that phytoplankton, a mixture of floating macrophytes, and submerged vegetation were the sources of organic matter. In general, the value of sediment organic carbon stocks tends to be lower in locations with intensive agricultural settlements than in forest areas. This study emphasizes that restoring lakeside wetland is vital in increasing sediment organic carbon stocks and maintaining lake sustainability.