Komala PS, Azhari RM, Hapsari FY, Edwin T, Ihsan T, Zulkarnaini, Harefa M. 2022. Comparison of bioconcentration factor of heavy metals between endemic fish and aquacultured fish in Maninjau Lake, West Sumatra, Indonesia. Biodiversitas 23: 4026-4032. Fish have a high risk of accumulating metals and poses a risk of entering human bodies through the food chain. This study aims to analyze the concentration of lead (Pb), mercury (Hg), and cadmium (Cd) spatially and temporally as well as the Bioconcentration Factor (BCF) in endemic fish (Rasbora argyrotaenia) and aquacultured fish (Oreochromis niloticus) in Maninjau Lake and its relationship to environmental parameters (pH, DO and temperature). Sampling was conducted at domestic, hydropower, fish cage, and endemic fisheries. Spatial and temporal distribution using one-way ANOVA with 95% significance, while parameter correlation using linear regression. Almost all heavy metals in both fish samples exceeded the permissible level except in endemic fisheries sites. Metal concentrations in both fish species spatially showed a significant difference, while temporally showed no significant difference. Rasbora argyrotaenia showed a slightly higher BCF value than O.niloticus. The BCF values were low accumulative with order Pb>Hg>Cd ??in R. argyrotaenia and Pb>Cd>Hg for O. niloticus. There is a strong and positive correlation between temperature and the BCF value of both fish species for the three different metals. Monitoring fish by keeping metal content within acceptable limits is necessary. Further research on risk analysis of fish consumption in humans is recommended.

Biochar is a known potential for nutrient removal in wastewater. This study focuses on the adsorption of rice-husk biochar to remove nutrients in the form of nitrate, ammonium, and phosphate in the wastewater. Two types of biochar production were used: laboratory-made biochar with variations of...

Lake Maninjau, like many surface water bodies worldwide, faces significant water pollution challenges due to extensive aquaculture activities, making it an ideal site to study the impact of fish farming on water quality, which has contributed to eutrophication and declining water quality. This study investigates the physicochemical parameters and pollution levels in the lake, aiming to provide insights into its environmental health. In August 2022, a comprehensive sampling campaign was undertaken at nine stations within the upper layers of open water and littoral zones of Lake Maninjau. In situ measurements, including temperature, dissolved oxygen, and pH, were conducted, accompanied by water sample collection for laboratory analysis of trace elements and heavy metals. Our study revealed notable variability in water parameters across different sites, with surface water layers exhibiting the greatest differences. While certain parameters such as temperature and conductivity remain relatively stable, pH levels show a decreasing trend with increasing water depth. Dissolved oxygen levels vary widely, while oxidation–reduction potential indicates water pollution, particularly in littoral zones. Potassium dominance within cations likely suggests anthropogenic influences, notably from aquaculture activities, that may also contribute to nutrient enrichment and heavy metal pollution. Elevated levels of total nitrogen and ammonia underscore the lake’s moderate pollution levels, with heavy metals such as mercury exceeding permissible limits, posing risks to aquatic life and human health.

This research performs an analysis of heavy metals in the waters and sediments of Lake Maninjau and the resultant pollution index value. The research was carried out in 11 locations, e.g., floating net cages, endemic fisheries, near settlements, hydropower plants, and seven rivers at the lake’s inlet and outlet at a depth of 0-1.5 metres. Determining the pollution index was conducted based on heavy metals and environmental parameters. Aside from Zn, the concentration of Cd, Hg, Pb, Cu in the waters in all locations exceeded the quality standard. The Hg metal in sediments in all areas exceeded the quality standard of contaminated soil. Concentrations of heavy metals in sediment are higher than that of heavy metals in water. 8 of 11 sampling locations were in the medium polluted category, with the fish cage location having the highest pollution index (PI) value. Anthropogenic activities such as aquaculture, water transportation, and settlements around the lake have an effect on the waters and sediments of the lake, characterised by heavy metal contamination. The lake’s quality must be continuously monitored, and wastewater management improved from activities around the lake to control heavy metal contamination. Further evaluation is required of the heavy metals contamination originating from anthropogenic activities and natural sources.

This study aimed to analyse the effect of anthropogenic activities on the spatial distribution of total nitrogen (TN) and total phosphate (TP) in Lake Maninjau, Indonesia, during the dry season. Sampling was carried out at ten observation locations representative for various activities around the lake. Cluster analysis and ANOVA were used to classify pollutant sources and observe differences between TN and TP at each site. Concentrations of TN and TP are categorised as oligotrophic-eutrophic. The ANOVA showed spatially that some sampling locations, such as the Tanjung Sani River, floating net cages, and hydropower areas have different TN concentrations. At the same time, TP levels were consistently significantly different across sampling sites. ANOVA and cluster analysis confirmed that floating net cages were the first cluster and the primary contributor to TN and TP. The second and third clusters come from anthropogenic activities around the lake, such as agriculture, settlement, and livestock. The fourth cluster with the lowest TN and TP is the river that receives the anthropogenic activity load but has a high flow velocity. The cluster change analysis needs to be conducted when there are future changes in the composition of floating net cages, agriculture, and settlements.

The purpose of this study was to analyze the organic content of Lake Maninjau based on depth stratification and its organics carrying capacity. Sampling was carried out at the location of lake utilization, namely in the lake center, settlement, hydropower, endemic fisheries, and fish cage following Indonesian National Standard SNI 6989.57: 2008. The parameters measured were BOD₅, COD and environmental condition such as pH, DO and temperatures. Lake Maninjau generally is polluted, especially for organic pollutants characterized by the BOD₅and COD values that did not meet the quality standard of Government regulations the Republic of Indonesia Number 82 the year 2001 class 2 according to its designation namely 21.87-47 mg BOD/L and 35.2-74 mg COD/L. Using one-way analysis of variance (ANOVA) at 0.05% level of significance both BOD₅and COD has a strong correlation with depth of the lake, at hydropower and endemic fisheries. At the shallow lake depths, water is easy to mix so that the organic matter distributed vertically. Fish cage has the highest contribution to the contamination of organic matter in the lake.