What contaminents release by fossil fuels in water?4 answersFossil fuels release various contaminants into water. The production of shale gas and shale oil involves hydraulic fracturing, which uses large amounts of water. This process can potentially contaminate drinking water resources with fluids from hydraulic fracturing or formation brines. Petroleum and petroleum products, including crude oil, can also pollute water through production, transportation, refining, and other activities. These pollutants can cause physiological disorders, diseases, and biological changes in the environment. Volatile fuel hydrocarbons and fuel additives, such as benzene, toluene, and methyl tert-butyl ether, can contaminate groundwater following release from underground storage tanks. Biodegradation limits the movement of these contaminants, but long-term monitoring is needed to understand their behavior. Fossil fuel extraction and refining processes, including natural gas fracking, can also pose risks to surface-water and groundwater quality.
How does the contaminant end up in water?5 answersContaminants end up in water through various human activities such as urbanization, industrialization, and agricultural activities. The overuse of pesticides and fertilizers, as well as sewage from residential and industrial areas, can find its way into aquatic environments, leading to water contamination. Dumping of industrial waste in low lying areas increases the chances of water contamination through percolation. Contaminants can reach water resources through underground and surface waters, as well as emissions from different industries. Wastewater discharged from industries may contain organic or inorganic matter, dyes, heavy metals, and pathogenic bacteria, which can contaminate water resources. Emerging contaminants can be introduced into water systems through wastewater treatment effluent, manufacturing, and agricultural use. The injection of toxic chemicals into the environment through industrialization and human activities has resulted in the presence of heavy metals in water bodies. Water can also be polluted by the disposal of untreated garbage, milling, and urbanization.
What are the most common contaminants found in mayonnaise?5 answersMayonnaise can be contaminated with various pathogens and contaminants. Salmonella, Clostridium perfringens, and Staphylococcus aureus are common pathogens found in homemade mayonnaise. These pathogens can survive in mayonnaise, but their survival is influenced by factors such as pH, choice of acidulant, and the presence of other ingredients like garlic or mustard. Commercial mayonnaise and mayonnaise dressings, on the other hand, pose negligible risk of contamination with enterohemorrhagic Escherichia coli (EHEC). However, it is important for consumers and food-service workers to practice good hygiene during the preparation, handling, and storage of mayonnaise-based recipes to prevent contamination. Additionally, lipid oxidation is a common issue in mayonnaise, leading to quality deterioration. Volatile oxidation compounds such as hexanal, pentanal, and 2-heptenal are markers of lipid oxidation in mayonnaise.
What are the most common contaminants in butter?5 answersThe most common contaminants found in butter include lactic acid bacteria such as Lactobacillus kefiri, Lactobacillus parakefiri, Lactococcus taiwanensis, and Lactococcus raffinolactis. Other contaminants detected in butter samples include Streptococcus spp. bacteria, opportunistic pathogens such as Bacillus cereus group, Pseudomonas aeruginosa, Cronobacter spp., Escherichia coli, Listeria innocua, Citrobacter spp., Enterococcus spp., and Klebsiella pneumonia. Additionally, Enterobacter cloacae, Staphylococcus epidermidis, and Cronobacter sakazakii have also been found in butter. Furthermore, butter can be contaminated with persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), hexachlorobenzene (HCB), and 2,2-bis (4-chlorophenyl)-1,1,1-trichloroethane (DDT). In addition, butter can be contaminated with psychrotrophic bacteria, molds and yeasts, coliforms, faecal coliforms, E.coli, and S.aureus. Finally, butter can also be contaminated with polybrominated diphenyl ethers (PBDEs).
Which contaminants are the most common in urban lakes?5 answersUrban lakes commonly contain contaminants such as nutrients, organic chemicals, and heavy metals. These contaminants can lead to eutrophication, which is the excessive growth of algae and other aquatic plants, resulting in oxygen depletion and degraded water quality. Nutrient pollution, specifically phosphorus, is a major contributor to eutrophication in urban lakes. Additionally, urban lakes can contain toxic organic chemicals, including hydrophobic organic contaminants (HOCs) such as polychlorinated biphenyls (PCBs), organochlorine pesticides, and polynuclear aromatic hydrocarbons (PAHs). These contaminants can enter the lakes through various sources, including atmospheric deposition, river inflows, groundwater flow, and direct and indirect discharges from industrial and municipal facilities. Overall, the presence of these contaminants in urban lakes highlights the need for effective pollution control measures to protect water quality and ecosystem health.
Which places in africa experience copper contamination in water exceeding standards?5 answersCopper contamination in water exceeding standards has been observed in the African Copperbelt region, specifically in the Democratic Republic of Congo (DRC) and Zambia. In the DRC, higher concentrations of trace elements, including copper, were found in drinking water obtained close to mining areas compared to Zambia. Additionally, the Kafue River in Zambia, particularly in the Copperbelt mining area, showed high concentrations of copper, indicating metal pollution. These findings highlight the environmental pollution and metal contamination issues in these regions, emphasizing the need for stronger environmental governance and efforts to mitigate the negative impacts of mining activities on water quality in the African Copperbelt.