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Dissolved humic substances (DHSs) are the major components of organic matter in the aquatic environment. DHSs are well known to considerably affect the speciation, solubility, and toxicity of a wide variety of pollutants in the aquatic environment. In this study, the effects of the toxicity of heavy metals and hydrophobic organic pollutants (HOPs) on Chlamydomonas reinhardtii in the presence of humic acid (HA) were examined by a microscale algal growth inhibition (μ-AGI) test based on spectrophotometric detection. To clarify the relationship between the chemical properties of HAs and the toxicity change of pollutants, eight HAs from different sources were prepared and used. HAs were responsible for mitigating the toxicity of Hg, Cu, pesticides (γ-HCH, 2,4-D, and DDT), and polycyclic aromatic hydrocarbons (PAHs) such as naphthalene (Nap), anthracene (Ant), and benzo[a]pyrene (BaP). In particular, an approximately 100-fold decrease in the toxicity of BaP was observed in the presence of 10 ppm HAs extracted from tropical peat. The results indicated that the carboxylic group content and the HA molecular weight are correlated to the changes in the heavy metal toxicity. For HOPs, the aromaticity and polarity of HAs are crucial for mitigating their toxicity. Furthermore, it was clearly shown that the lake water including a high concentration of DHSs collected from Central Kalimantan, Indonesia, reduced the toxicity of Hg and γ-HCH on Chlamydomonas reinhardtii. Graphical abstract.

Inland water resources on Rote Island are more than 80 lakes and ponds. One of them is Dead Sea Lake Oemasapoka. Based on previous research, this lake showed its uniqueness in high salinity values (40 - 42 ppt). The purpose of this study was to reveal heavy metal concentrations. We conducted an analysis of heavy metal parameters using neutron activation analysis. Sample irradiation was carried out in the Rabbit system of G.A Sywabessi Multipurpose Reactor in Serpong, a neutron flux of ≈ 3 x 1013 n cm−2s−1. Quantitative analysis was performed using the INAA comparison method and INAA-ko-IAEA software. The results showed Chlorin (Cl) and Sodium (Na) were two dominant parameters which the higher Chlorin (Cl) concentration was obtained from H2S smelling water (3,827.68 ± 459.60 mg/L) than those from freshwater and saltwater environments (549.67 ± 47.40 mg/L and 2,503.83 ± 214.98 mg/L, respectively). Meanwhile, Sodium (Na) concentration was higher from saltwater (5,686.10 ± 77.43 mg/L) than in those from freshwater and H2S smelling water environments (481.86 ± 7.28 mg/L and 3,387.96 ± 29.05 mg/L, respectively). It seems the geological processes in this area are unique and should be explained in more detail the impacts on biota in this lake.

Ledulu Lake is one of the lakes in the Rote Ndao Region. Lake Ledulu was formed in the Quaternary period with Cenozoic constituents and Neogene deposits based on geological formations. The formations found in the Lake area are sediment, chemical, limestone. The purpose of this study was to measure the metal content in the lake water and its absorption by aquatic vegetation in the ecosystem of Ledulu lake, using Instrumental neutron activation analysis (INAA) technique. NAA is one of the modern methods that is able to measure the level of heavy metal uptake in aquatic biota (water animals and aquatic plants). The metal content in the water of the lake (mg/L) is: Bromine 405.06, Calcium 7,195.66, Cerium 9.10, Cobalt 2.43, Chromium 45.90, Lanthanum 12.07, Magnesium 1,189.93, Sodium 24,382.31. Aquatic plants that absorb heavy metals in lake Ledulu are Panicum sp, Ludwigia adscendens (L.) H.Hara, Ottelia alismoides (L) pers, Najas sp, Ipomea aquatica Forssk, Pontederia korsakowii (Regel & Maack) M.Pell. & C.N.Horn, Callitriche sp, Bacopa monnierii, and Nymphaea alba L. Sodium is not absorbed by Panicum sp, Ludwigia adsendence (L), and Nymphaea alba. Lanthanum is only absorbed by Panicum sp and Callitriche sp. All other elements can be absorbed by aquatic plants in the Ledulu lake ecosystem with different absorption concentrations.

Gunung Putri pond located in Bogor Regency functions as water reservoir, agricultural irrigation, fisheries activities, as well as domestic and industrial waste disposal sites. Human activities around the pond are thought to cause a decrease in the physical, chemical and biological qualities of the pond water. Therefore, research on the pollution status needs to be carried out for the management of pond water resources. The purpose of this study was to determine the status of Gunung Putri pond pollution as measured by the physical and chemical parameters of its waters. The study was conducted from February to March 2019. The methods used in determining the status of pollution were the STORET method and the Pollution Index (IP). The results of water quality measurements carried out in the field were compared with water quality standards, and were used in determining the status of pollution according to each method. Both methods produce different water quality status for each station, with the STORET method score ranging -20–0 and the Pollution Index score ranging 0.31–3.92. The STORET method more accurately explained the pollution conditions in Gunung Putri pond and showed that the water was in mild to moderate polluted conditions. Based on the two methods used, the highest pollution status was found at Stations 3 and 5. Organic material with high content was suspected as the cause of pollution because the most dominant water quality parameter in determining pollution status was COD. Therefore, Gunung Putri pond cannot support fishery activities because the water quality parameters of COD and DO at Stations 3 and 5 do not meet the water quality standards for the class II and III waters based on the Government Regulation No. 82 of 2001. Industrial, domestic, and agricultural wastes entering the waters of Gunung Putri pond contribute to the pollution of the aquatic environment which can be seen from the high COD value.

Tropical peatlands play an important role in the global carbon cycle, and therefore, their stability has important implications for climate change. In this study, we evaluated the effect of fire on the physical, chemical, and biological properties of peat soils in Indonesia for three years following exposure to fire. The results of the thermal analysis suggest that the organic matter contents of surface soils significantly decreased because of peat fires and that charred materials were produced in the subsurface layer of the burned soils. The atomic ratios of the burned soils and the thermally treated samples indicate that the Indonesian peat soils were dehydrated by these low-severity fires. The microbial abundance and phosphatase activity in the burned soils significantly decreased compared to those of the unburned soils. Leaching of the dissolved organic carbon (DOC) concentration from the burned soils is lower than that from the unburned soils. The obtained laboratory results indicate that the concent...

In this work, laser desorption ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (LDI–FTICRMS) was used to investigate the molecular composition of a peat fire and laboratory heated soil organic matter (SOM). SOM isolated from soils obtained from unburned and burned sites at Central Kalimantan, Indonesia, were analyzed with LDI–FTICRMS. About 7500 peaks were found and assigned with molecular formulas for each mass spectrum. SOM isolated from fire-affected soil sites are relatively more abundant in low oxygenated classes (e.g., O1–O5) and thermally stable compounds, including condensed hydrocarbon and nitrogen heterocyclic compounds. Abundances of highly condensed hydrocarbon compounds with carbon number > 30 were increased for the fire-affected SOM. In vivo heating experiments were conducted for SOM extracted from unburned sites, and the prepared SOMs were analyzed with LDI–FTICRMS. Overall, the same trend of change at the molecular level was observed from both the laboratory heated and the peat fire-affected SOM samples. In addition, it was observed that heat caused the degradation of SOM, generating lignin and tannin-type molecules. It was hypothesized that they were formed by thermal degradation of high molecular weight SOM. All the information presented in this study was obtained by consuming ~ 5 μg of sample. Therefore, this study shows that LDI–FTICRMS is a sensitive analytical technique that is effective in obtaining molecular level information of SOM.

Artisanal Small Scale Gold Mining (ASGM) is the largest source of Hg pollution in the environment. Indonesia has ratified the Minamata convention in 2013. Mercury pollution to the aquatic environment is a great concern due to its potential impact may threat the aquatic ecosystem. In this study we conduct a mini literature review dealing with the impact of mercury pollution on aquatic organisms in Indonesia, this study provides an overview of mercury contamination in fish and macroinvertebrates in Indonesia which is related to ASGM activities, based on peer-reviewed literature recorded in the Scopus database (www.scopus.com). Keywords mercury OR Hg AND ASGM AND Indonesia was used to retrieve literatures from the database. The identified articles were screened for relevance at the title, abstract, and full text level using predefined inclusion criteria. The mercury accumulation in freshwater fish and macroinvertebrates were ranged from 0.005 mg/kg to 19 mg/kg, and from 0.002 mg/kg to 1,46 mg/kg, respectively. While mercury accumulation in in marine fish and macroinvertebrates were from 0,014 mg/kg to 57 mg/kg and 0.002 mg/kg to 2.99 mg/kg, respectively. The highest mercury accumulation in freshwater fish was found in Manado, North Sulawesi and the lowest was in Talawaan Watershed, North Sulawesi, while in Marine fish, the highest Hg accumulation was also found in Manado, North Sulawesi, and the lowest accumulation was found in Buyat, North Sulawesi. Introduction

Kapuas River in West Kalimantan with over 1,143 km is the largest river in Indonesia. It serves as a main refuge for high potential biodiversity. Oxbow lakes along the Kapuas River are of high ecological essential due to the number and the diversity of habitats they provide. In addition, oxbow lakes are critical components of the floodplain systems of lowland rivers. The objective of this study was to explore the diversity of oxbow lakes and their connectivity to the main river. We conducted fieldwork to measure water quality and ecological components at 12 oxbow lakes along the Kapuas River and two lakes in the Sentarum complex in January - February 2020. We measured the environmental parameters including water depth, water temperature, Secchi/transparency, pH, dissolved oxygen concentration, chlorophyll-a concentration, total nitrogen, and total phosphorus concentrations. Aquatic biota, including phytoplankton and zooplankton community structures, were also observed at 12 oxbow lakes along the Kapuas River and two lakes in the Sentraum complex. The sampling points represented both permanent and non-permanent connectivity of the oxbow lakes to the main river. The result indicates the variability of environmental characteristics between the lakes, based on water quality and biota analysis; for example, water acidity, as indicated by pH, was likely to seem like the main variable determining the oxbow lake biota. Also, the habitat connectivity of oxbow lakes to the main river has significantly influenced the biotic composition.

The composition of carbon (C), nitrogen (N) and C/N ratio in the sediment lake provided valuable information about the sources of organic matter and depositional basin. In a floodplain lake, sediment deposition is very dynamic related to seasonal changes. The aim of the study is to reveal the composition of C, N and C/N ratio in sediment lake in the permanent zone and non-permanent inundation zones and to predict the sources of organic matter in sediment lake. The study was conducted in March 2017 in Lake Tempe, South Sulawesi, Indonesia. Sediment samples were collected from six zones. C-organic was determined according to modification of the Walkley-Black method. Nitrogen was determined by the Kjeldahl method. The result showed that carbon organic in this sediment lake was about 4.7 – 5.8 %. The lowest was found in the nonpermanent zone. The highest value was found in the permanent zone, indicating that the organic carbon has been accumulated for long period in this permanent zone. Nitrogen organic content in sediment was about 0.30 to 0.50 %, this value was relatively low. It probably nitrogen content has been released to the water column or rapidly up-taken by microbes. C/N ratio in the sediment of Lake Tempe was in the range 13.1 to 18.1, this value indicated that organic matter originated from a mixture of plankton and macrophytes.

Phytoplankton Community Relationship with Nutrient Content in the Littoral Areas of Lake Maninjau and Ranggeh River, Agam Regency. Phytoplankton in Lake Maninjau is a food source for fish and plankton-eating fish such as Bada fish (Rasbora sp.), Lake Maninjau endemic fish that have high economic value. Nutrients such as nitrogen and phosphorus would be the limiting factors for phytoplankton growth. This observation aims to determine the composition and abundance of phytoplankton to nutrient content in the littoral areas of Maninjau Lake and Ranggeh River. The observations were conducted on April, July, August, September, October, and November 2018 at several observation stations. The results show that there were phytoplankton groups, ie. Chlorophyta (53 species), Bacillariophyta (35 species), Cyanophyta (six species), Euglenophyta (five species), and Dinophyta (two species). The phytoplankton abundance in Maninjau littoral region ranged from 0.07 x 106 - 5.8 x 106individual.L-1, while in Ranggeh River ranges from 0.0016 x 106 - 2.1 x 106individual.L-1. In July 2018, the most abundant species was Microcystis aeruginosa (Cyanophyta), in August and September were Synedra ulna (Bacillaryophyta) while in October and November were Cylindrospermopsis raciborskii (Cyanophyta). Based on the diversity index, evenness index and dominance index, the phytoplankton community in the littoral area of Maninjau Lake was unstable compared to Ranggeh River. Principal component analysis showed that the abundance of Cyanophyta in the Maninjau littoral area was influenced by the concentration of phosphorus.

Lake Tempe in South Sulawesi is one of the floodplain lakes in Indonesia that has a unique phytoplankton characteristic. This study aims to see the abundance of phytoplankton and their relationship with physico-chemical parameters in Lake Tempe. Observations were conducted in March and May 2017 in six zones of the lake, consist of 5 zones are non-permanent areas and 1 zone are permanent area. Dissolved oxygen, pH, temperature, turbidity, total dissolved solids, transparency, chlorophyll-a, total nitrogen, and total phosphorus were measured to determine the water quality. Phytoplankton abundance was calculated using the Sedgewick Rafter Method. Phytoplankton community structure was analyzed by Diversity Index, Evenness Index, and Dominance Index. A total of five phyla and 80 species of phytoplankton were found in Lake Tempe, consists of Bacillariophyta, Chlorophyta, Cyanophyta, Dinophyta, and Euglenophyta. The abundance of phytoplankton ranged between 1,133–701,390 individual L−1. Moderate to high diversity (1.751–3.859) and low uniformity (0.069–0,306) among species in the phytoplankton community was found in Lake Tempe. The dominant species was found at two sampling sites (Z.2.1 and Z.2.2), namely Aphanocapsa. The presence of Cyanophyta in Lake Tempe is related to the total phosphorus value.

Ranggeh River, located in Nagari Batang River - Agam Regency, is one of the natural habitats for native fishes of Lake Maninjau. Phytoplankton is a microorganism that has an important role in the aquatic ecosystem, as a primary producer in the food chain and to provide a food source for the higher organisms such as zooplankton and fish. The existence of phytoplankton in the river is influenced by physical and chemical factors. This study was aimed to reveal the correlation of the phytoplankton abundance and physicochemical parameters in Ranggeh River. The observations were conducted in February, March, and April 2019 at the upstream (SR 1, SR 2 and SR 3) and the downstream areas (SR 4 and SR 5) of Ranggeh River. The parameters observed were phytoplankton abundance and some water quality parameters. The phytoplankton community structure was analyzed by the ecological index. The highest and lowest abundance of phytoplankton was found in SR 4 and SR 1, respectively. Bacillaryophyta has been recorded as the most dominant group (98.30% to the total phytoplankton population), followed by Chlorophyta (1.40%), Cyanophyta (0.27%), and Euglenophyta (0.04%). Based on the ecological index, the phytoplankton communities at SR2, SR 3, SR 4 and SR 5 are unstable, and there is a species that dominates namely the Navicula elegans, Navicula pupula and Synedra ulna from the Bacillaryophyta group. According to values of phytoplankton abundance, total nitrogen, total phosphorus, chlorophyll-a, and diversity index, Ranggeh River was mesotrophic water.

River Bonan Dolok in Samosir is located on the watershed of Lake Toba, an ancient volcanic lake in North Sumatra. Some parts of this river bordered with paddy fields, a common source of cadmium through the leaching process, which then released into the water body. Meanwhile, this river has been proposed as endemic fish (called in the local name as Ihan) conservation area and eco-tourism area. Therefore a scientific reference base management concept is needed. Spatial distribution of cadmium (Cd) must be revealed since this metal is very toxic and can be easily transferred and accumulated in the aquatic food chain. This study aims to inform the distribution of Cd in water, microalgae biomass and sediment. All samples were taken compositely from the upper stream (Station 1), Station 2, Station 3, and lower stream (Station 4) in April 2019. The structure of microalgae community is also identified. The results show that Chlorophyte (mostly consisted of Microspora sp) biomass at Station 2, has the highest Cd concentration (0.57 µgCd/g dry weight). While Cyanophyte (dominated by Microcyctis aeruginosa) even observed bloomed at station 4, shows a lower Cd concentration (0.12µgCd/g dry weight). The distribution of Cd in water and sediment (particle size of ≤63 µm) at those sampling stations as well as some water quality also discussed. The range of Cd concentration in water was 0.02 to 0.64 µg Cd/L, while that in sediment was 0.10 to 0.39 µgCd/g dry weight. These data are expected to be used as essential references for developing the management concept of Bonan Dolok ecotourism area in the future.

Technology always developed all the time. It makes many humans utilize the technology for doing everything. Not only used for doing something good, but there are many humans use it for doing criminal, such as robbing. On the other hand, there is something found for preventing that problem. It is a tool for detecting face. Face recognition is made for identifying a face by digital image. This paper presents a research on security of a room. The room can only be opened by identifying ad matching the face of the one that has been inputted to the data base of the system. Haar cascade classifier is used in this research. The processes of identifying of the objects were discussed in this paper. From the experimental test, it can be concluded that the proposed method is effective enough in processing the features of the objects.

Early View (Online Version of Record published before inclusion in an issue), Humic acid (HA), a group of high-molecular weight organic compounds characterized by an ability to bind heavy metals, is normally found in natural water. Although the impairment of vascular endothelial cells in the presence of humic substances has been reported to be involved in some diseases, the mechanisms responsible for this involvement remain unclear. In this study, we examined the cytotoxicity of HA obtained from peatland in Central Kalimantan, Indonesia, to human vascular endothelial cells, as well as the mechanisms behind these effects. It was found that 50 mg/L HA showed cytotoxicity, which we considered to be mediated by apoptosis through the mitochondrial pathway because of an increase in the expression of caspases 6 and 9 in response to HA administration. In addition, this cytotoxicity was enhanced when cells in this experimental system were exposed to oxidative stress, while it was decreased by the addition of vitamin C. Thus, we conclude that the apoptosis induced by HA depends upon oxidative stress. Furthermore, an iron chelator, DFO, showed a tendency to decrease HA-induced cytotoxicity, suggesting that iron may potentially mediate HA-induced oxidative stress. In conclusion, long-term consumption of HA-rich water obtained from our study area may cause damage to endothelial cells and subsequent chronic health problems. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.

The pollution of water by heavy metals is one of the most serious problems in the developing countries, where watercourses play important roles in transport and economic activities. The aim of this study was to examine whether Hyposarcus pardalis, a fish species widespread in the freshwater environment in Indonesia, could be used as a biomarker for environmental pollution by metals. To this effect, the concentrations of metallothioneins and metals in the livers and kidneys of H. pardalis were measured. In addition, to clarify the relationship between metallothionein concentrations and metal exposure, the concentrations of metallothioneins and metals were determined in the liver and the kidney of fish exposed to 50 and 500 ppb Cu and 500 ppb Mn, compared with those kept in clean water. Sufficient concentrations of metallothionein were detected in fish captured from Lake Rawakalong located in an industrial area in the suburbs of Jakarta. The results of exposure experiments suggested that H. pardalis retained a history of pollution in its organs for a long duration, and the metals bound to metallothioneins in the liver and kidney could be replaced with Cu following exposure. In conclusion, the hepatic and renal metallothioneins in H. pardalis are a useful candidate biomarker for monitoring heavy metal contamination.

To compare water quality in rivers of developed and developing countries, a study based on physicochemical parameters and dissolved metals levels was conducted. Water samples were collected from selected sites in Dhaka, Bangladesh; Hokkaido and Osaka, Japan; Erdenet, Mongolia and West Java, Indonesia. Analysis of least significant differences revealed that most water quality parameters were within comparable low levels in both developed and developing countries. The dissolved metals concentrations were found to be similar and below those of water standards except for manganese and cadmium at every sampling point, and lead in Erdenet, Mongolia. Some metals showed high enrichment factors in the rivers of Osaka, Japan and Erdenet, Mongolia, indicating accumulation possibility of metals in the river-bed sediments. High concentrations of dissolved organic carbon, Escherichia coli and dissolved metals suggested greater water pollution in some rivers of developing countries than in the rivers of Japan. Principal component analysis showed strong correlations between “dissolved organic carbon and chemical oxygen demand” and “conductivity and total dissolved solids” at each sampling point, and E. coli, nitrate (NOmath image), nitrite (NOmath image), and pH levels were found to be higher in the rivers of Dhaka and Erdenet. In addition, there were high levels of Al and Zn in West Java, Pb in Erdenet, and Mn, Fe, and Cr in the rivers of Dhaka and Japan. Based on pressures and impacts, it is evident that dissolved metal, organic, and fecal pollution in the rivers of developing countries are in somewhat dreadful condition in comparison with the rivers of developed country.

Humic acid (HA), a group of high-molecular weight organic compounds characterized by an ability to bind heavy metals, is normally found in natural water. Although the impairment of vascular endothelial cells in the presence of humic substances has been reported to be involved in some diseases, the mechanisms responsible for this involvement remain unclear. In this study, we examined the cytotoxicity of HA obtained from peatland in Central Kalimantan, Indonesia, to human vascular endothelial cells, as well as the mechanisms behind these effects. It was found that 50 mg/L HA showed cytotoxicity, which we considered to be mediated by apoptosis through the mitochondrial pathway because of an increase in the expression of caspases 6 and 9 in response to HA administration. In addition, this cytotoxicity was enhanced when cells in this experimental system were exposed to oxidative stress, while it was decreased by the addition of vitamin C. Thus, we conclude that the apoptosis induced by HA depends upon oxidative stress. Furthermore, an iron chelator, DFO, showed a tendency to decrease HA-induced cytotoxicity, suggesting that iron may potentially mediate HA-induced oxidative stress. In conclusion, long-term consumption of HA-rich water obtained from our study area may cause damage to endothelial cells and subsequent chronic health problems.