Phosphorus load base carrying capacity estimation for fish culture in Lake Ranau in Indonesia

Carrying capacity is the ability of waters to accommodate pollutant load inputs without reducing the water quality. For aquaculture in floating net cages (FNC), the carrying capacity is a criterion to achieve the maximum fish production based on the level of total phosphorus (TP) released from the activity, which is still acceptable according to utilisation purposes. Lake Ranau in Sumatra is essential in supporting the socio-economic needs of the people in the surrounding areas, including FNC activities. The development of FNC as an aquaculture model in open waters will have a positive value as long as it is within the limits of water carrying capacity. Thus, the carrying capacity of Lake Ranau waters needs to be estimated to provide optimal direction for FNC development in line with other activities such as tourism. The carrying capacity was estimated using the Beveridge (1987) formulation that has also been adopted into the Ministry Regulation of Environment number 28/2009. As a limiting factor for tourism purposes, the status trophic of waters should be oligotrophic or oligo-mesotrophic. Therefore, the fish production that can be achieved is between 0 tons/year (oligotrophic scale) to 1,662 tons/year (oligo-mesotrophic scale).

Can Ephemeroptera, Plecoptera, Trichoptera (EPT) assemblage reflect nitrogen and phosphorus load in the riverine ecosystem?

The aim of this paper is to make a comparative analysis of benthic macroinvertebrate compositions in streams and rivers in Croatia with relation to different physical-chemical factors, especially nutrients. Samples were collected according to the AQEM method. At all the sites, 20 taxa were recorded of which Turbellaria, Gastropoda, Bivalvia, Oligochaeta, Hirudinea, Crustacea, Ephemeroptera, Odonata, Plecoptera, Heteroptera, Trichoptera, Coleoptera and Diptera were included in the present study. Water temperature mostly affected the composition of benthic macroinvertebrates to which it was inversely proportional. Nutrient enrichment, i.e., higher concentrations of ammonium, nitrates, nitrites, total nitrogen, orthophosphates and total phosphorus mostly affected Ephemeroptera, Plecoptera, Trichoptera and Diptera, by decreasing their diversity.

An evaluation of British Columbia's medications return program as a management framework for collecting unused/expired pharmaceuticals

Lake Simcoe is a major source of fresh water supply and serves as a favorite hub for recreational activities in southern Ontario. The cold water aquatic life of this Lake is facing serious threats due to depleted levels of oxygen caused by excessive growth of algal plants. The major reason for this growth is the entrance of high phosphorus loads through heavy stream discharges in the months of January until April. The results of analysis of phosphorus concentration and flows conducted in this project shows a direct dependence of phosphorus load on flow. Although the relation of rainfall and phosphorus load could not be supported by strong statistical evidence, the flow variations have been shown to be the major cause of variations in phosphorus load. The control strategies should be focused on reducing the generation of phosphorus at source level and preventing the direct entry of heavy flushes in the lake though Best Management Practices (BMPs), including detention facilities.

An evaluation of British Columbia's medications return program as a management framework for collecting unused/expired pharmaceuticals

Lake Simcoe is a major source of fresh water supply and serves as a favorite hub for recreational activities in southern Ontario. The cold water aquatic life of this Lake is facing serious threats due to depleted levels of oxygen caused by excessive growth of algal plants. The major reason for this growth is the entrance of high phosphorus loads through heavy stream discharges in the months of January until April. The results of analysis of phosphorus concentration and flows conducted in this project shows a direct dependence of phosphorus load on flow. Although the relation of rainfall and phosphorus load could not be supported by strong statistical evidence, the flow variations have been shown to be the major cause of variations in phosphorus load. The control strategies should be focused on reducing the generation of phosphorus at source level and preventing the direct entry of heavy flushes in the lake though Best Management Practices (BMPs), including detention facilities.

Phosphorus load in outdoor areas for laying hens and capacity of phosphorus retaining materials to reduce the environmental impact

This study investigated manure loads in outdoor paddocks for laying hens and the capacity of two phosphorus (P) retaining materials for reducing leaching from manure in areas with high hen density. Inventories on two commercial farms during 2 years (2017 and 2018) of the impact of hens (groups of 3000 hens) on vegetation, as a proxy for land use by hens, showed that 16–21% of outdoor area in grassland paddocks and 22–39% of area in a forest paddock were used by the hens. Sand and limestone were tested as P retention materials in areas with high manure load in a field study during the outdoor season for laying hens (May 1 to October 31 in 2018). The materials were placed on the ground (0.2 m deep bed, 3.3 m wide) outside the pop-hole in paddocks with 76 hens. The average numbers of hens outdoors were recorded at 9 am and 3 pm daily. There was no significant difference between the materials concerning distribution of hens, and they seemed not to prefer any material more than the other. When cylinders containing the spent materials were exposed to simulated rainfalls in a laboratory study, the P concentrations in drainage water were high for all materials, including a control with gravel (58–136 mg PO4-P L−1 and 130–197 mg total-P L−1). On average, 14% of manure P retained in the sand and limestone materials was leached after 100 mm of simulated rainfall. Thus, these materials may act as physical filters for P in manure, but to reduce the risk of P losses to waters during the following winter, they need to be removed from the paddocks and preferably used as potential P fertilizers on arable land.