China
Africa
Explore chapters and articles related to this topic
Eutrophication
Published in Yeqiao Wang, Fresh Water and Watersheds, 2020
Kyle D. Hoagland, Thomas G. Franti
Eutrophication is the nutrient enrichment of surface water and the subsequent impacts on water quality and the aquatic ecosystem. The overabundance of plant nutrients, usually nitrogen and phosphorus—but sometimes silicon, potassium, calcium, iron, or manganese—creates the conditions for excessive plant growth.[1] Algal blooms are an example of excessive growth caused by oversupply of nutrients. A body of water is classified by its trophic state based on the amount of nutrients supplied to it. An oligotrophic state is low in nutrients, a mesotrophic state is intermediate, and a eutrophic or hypereutrophic state is high in nutrients.[2] Eutrophication is a natural process. However, as a natural process it takes generations, or even thousands of years, for eutrophication to cause significant changes. It is the acceleration of the process, known as cultural eutrophication, that is of the greatest concern to water quality and the health of aquatic systems.
Basic aquatic ecosystems
Published in Nick F. Gray, Water Science and Technology: An Introduction, 2017
Aquatic ecosystems are made up of a wide variety of species including bacteria, plants (algae as well as floating and rooted aquatic plants), zooplankton, annelids (worms and leeches), molluscs (mussels and snails), arthropods (crustaceans and insects), fish, birds and mammals, all interacting to form a community. While they can be studied at ecosystem, community, population, species and even at the genetic level, freshwater monitoring is normally done at the community level by examining the organisms present at individual sites and comparing this in terms of diversity and abundance to other sites within a catchment (Table 8.19).
Organisation at the Ecosystem Level
Published in Kimon Hadjibiros, Ecology and Applied Environmental Science, 2013
Aquatic ecosystems are distinguished into the marine ones, which include open and closed seas, and the freshwater ecosystems, which include lakes, rivers, springs and most of the wetlands. A special case of marine ecosystems are coastal aquatic ecosystems; they generally are wetlands. Underground waters are not considered to be autonomous ecosystems. The study of aquatic ecosystems is especially important for the thorough examination of most of the biogeochemical cycles as well as the various water pollution phenomena (Chapter 8).
Life cycle impacts of induction furnace technology for crude steel production: case study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Aysegul Avinal, Pinar Ergenekon
From Figure 3, it is evaluated that IF-TR has the highest impact on the categories of fine particulate matter formation (FPMF), freshwater eutrophication (FWEu), human non-carcinogenic toxicity (HNCT), and terrestrial acidification (TA). Impact results for the categories of FWEu, HNCT, TA, and mineral resource scarcity (MRS) from IF-TR and IF, electricity-Europe are higher than either EAF. For IF-TR and IF, electricity-Europe, a striking decrease in terrestrial ecotoxicity (TEc) is noticeable. However, when comparing the scenarios in which European electricity is utilized (IF, electricity-Europe, and EAF-Europe), IF technology seems better for the categories of fossil resource scarcity (FRS), human carcinogenic toxicity (HCT), ozone formation (OF), TEc, and WC. The results of freshwater ecotoxicity (FWEc), global warming (GW), ionizing radiation (IRad), land use (LU), marine ecotoxicity (MEc), marine eutrophication (MEu), ozone formation (OF), and stratospheric ozone depletion (SOD) categories were also given in Figure 3. Here, FWE, HH, TE, and AE represent the freshwater ecosystem, human health, terrestrial ecosystem, and aquatic ecosystem, respectively.
Temporal distribution, source apportionment, and pollution assessment of metals in the sediments of Beas river, India
Published in Human and Ecological Risk Assessment: An International Journal, 2018
Vinod Kumar, Anket Sharma, Renu Bhardwaj, Ashwani Kumar Thukral
The results of metals in the present study were found below the geochemical data of South East Queensland and environment protection department data of sediment quality of China. Results of CA, PCA–FA suggested that anthropogenic activities, lithogenic factors, and sand intrusion are the main sources of metals in the sediments of River Beas. Metals such as Zn, Mn, Cr, Cu, Co, Ni, and Cd showed moderate to high enrichment indicating contribution of anthropogenic activities and lithogenic factors. Results of CF, EF, EF%, and Igeo showed that Cd, Mn, and Cr are highly enriched in the sediments of present study. From the multi-element indices, it was found that MPI and MRI showed more contamination as compared to PI and RI. Cd followed by Ni and Cr showed moderate to high ecological risk in the sediments of present study. The measures to decrease the content of metals such as Cd, Ni, and Cr in sediments are needed for river protection and their future restoration. It can be done by introduction of some aquatic plants which are good phytoremediators. This will help in removing Cd, Ni, and Cr which may reduce the ecological risks caused by these metals. Additionally, the evaluation of metal pollution in this study will facilitate the assessment of aquatic ecosystem health of the River Beas. It is also important to continuously scrutinize these metals to better understand their pollution and decrease their ecological risks in the region.
Ecological risk of heavy metals in sediment of an urban river in Bangladesh
Published in Human and Ecological Risk Assessment: An International Journal, 2018
Md. Saiful Islam, Ram Proshad, Saad Ahmed
In order to predict the metal pollution in sediment of the studied river in Bangladesh, the available data for a comparative analysis with background and toxicological reference values and some studied river sediment values are summarized in Table 3. It was noted that the average concentration of studied metals in sediment samples exceeded the geochemical background i.e. average worldwide shale standard and continental upper crust value. The mean concentrations of all the analyzed heavy metals were also higher than those of the U.S. Environmental Protection Agency's (USEPA) toxicity reference values (TRV), lowest effect levels (LEL) and probable effect levels (PEL) (Table 3), which are expected to be frequently associated with the adverse biological effects. The mean concentrations of heavy metals in sediment of this river were higher than those of the sediment of Korotoa and Bangshi Rivers in Bangladesh and other study rivers from other countries (Table 3). The results indicated that the levels of heavy metals in sediment of the studied river might create an adverse effect on the aquatic ecosystem. Elevated concentrations of heavy metals in surface sediments of Buriganga River were found, which indicated that the urbanization drove metal contamination in surface sediment (Li et al.2012). During our sampling, we observed unplanned tanning activities from 270 tanneries, leachates from defused Ni-Cd batteries, Cd-plated items, lead smelting and lead products manufacturing at the sampling sites, which can be coherent to the presence of metals in sediment.