Instructions: Metals Are Basic Elements That Do Not Degrade
Instructionsmetals Are Basic Elements That Do Not Degrade Any Further
Research a metal that was discussed in the textbook reading such as mercury, arsenic, or cadmium. Create a PowerPoint presentation at least seven slides in length, discussing the following: background information on the metal, the cornerstone xenobiotic pharmacokinetic properties and effects of the metal, the bioaccumulative effects of the metal in the environment and how it affects humans and the environment, and concentration of metal that is considered toxic and symptoms of toxicity by this metal.
Your PowerPoint should be a culmination of what you have learned throughout the course. For instance, if the metal has particular effects on a certain body system or organ, be sure to give information about these effects. The assignment should meet the following requirements: The length should be a minimum of seven slides, not including your title and reference slides. Use speaker notes to explain the key points that are provided in the slides. Include at least two visual aids and/or graphics. A minimum of two credible sources should be used for this assignment, and the references should be properly cited in a reference list at the end of the PowerPoint.
Paper For Above instruction
The metal selected for this comprehensive review is mercury (Hg), a pervasive environmental contaminant with significant health implications for humans and ecosystems. Mercury is a naturally occurring element found in various forms—elemental, inorganic, and organic—each with distinct pharmacokinetic properties and toxicities. Understanding mercury's background, pharmacokinetics, bioaccumulation, and toxicity thresholds is vital for assessing its impact and formulating effective mitigation strategies.
Background Information on Mercury
Mercury is a heavy, silvery-white metal with a high density and unique physical properties, such as being liquid at room temperature. Its natural sources include volcanic activity, mineral deposits, and weathering of mercury-bearing rocks. Anthropogenic sources, however, significantly contribute to environmental mercury levels, primarily through coal combustion, artisanal gold mining, and industrial processes (Pacyna et al., 2016). Mercury exists in three primary forms: elemental mercury (quicksilver), inorganic mercury salts, and organic methylmercury, each with distinct behaviors in biological systems.
Pharmacokinetic Properties and Effects of Mercury
Mercury's pharmacokinetics vary according to its chemical form. Elemental mercury vapor, when inhaled, is rapidly absorbed through the lungs, reaching the bloodstream within minutes (WHO, 2017). Once in the body, elemental mercury can cross the blood-brain barrier and placental barrier, exerting neurotoxic effects. Inorganic mercury salts are poorly absorbed via the gastrointestinal tract but can accumulate in kidneys, leading to nephrotoxicity. Methylmercury, the organic form, bioaccumulates efficiently in fish and seafood, and upon ingestion, penetrates the central nervous system, causing neurological deficits (Clarkson & Magos, 2006).
The primary effects of mercury exposure include neurological impairment, cognitive deficits, and motor disturbances, especially in developing fetuses and children. Chronic exposure may also result in kidney damage, immune dysfunction, and cardiovascular issues. The toxicity depends on the chemical form, dose, duration of exposure, and individual susceptibility.
Bioaccumulative Effects in the Environment and Human Impact
Mercury's ability to bioaccumulate stems from its methylated form, which is highly soluble and readily absorbed by aquatic organisms. Through the food chain, mercury concentrations increase, with top predators like large fish, marine mammals, and humans exhibiting the highest levels (Lindberg et al., 2014). This bioaccumulation poses significant risks to human health, particularly for populations that consume large quantities of fish and seafood.
Environmental contamination occurs via industrial emissions, improper waste disposal, and legacy contamination. Mercury deposits in water bodies undergo methylation by microorganisms, creating methylmercury. This form readily accumulates in aquatic food webs, leading to widespread environmental poisoning and impacting biodiversity.
Toxic Concentration Levels and Symptoms of Toxicity
Guidelines from agencies like the World Health Organization and the U.S. Environmental Protection Agency establish threshold levels for mercury exposure. The EPA's reference dose (RfD) for methylmercury is set at 0.1 micrograms per kilogram of body weight per day (EPA, 2012). Symptoms of mercury toxicity include neurobehavioral changes, cognitive deficits, tremors, weakness, visual and auditory impairments, and in severe cases, coma or death. In pregnant women, exposure can result in fetal developmental delays, cerebral palsy, and other congenital disabilities.
Implications for Human Health and Policy
Addressing mercury toxicity requires strict regulation of industrial emissions, safe waste disposal practices, and public health initiatives promoting awareness and fish consumption advisories. Further research into mercury's pharmacokinetics and biotransformation can help develop targeted interventions to reduce exposure and mitigate health impacts.
References
- Clarkson, T. W., & Magos, L. (2006). The toxicology of mercury and its chemical compounds. Critical Reviews in Toxicology, 36(8), 609–662.
- EPA. (2012). Mercury Study Report to Congress. United States Environmental Protection Agency.
- Lindberg, S. E., et al. (2014). Global methylmercury cycling. Environmental Science & Technology, 48(24), 13652–13655.
- Pacyna, J. M., et al. (2016). Global emission of mercury to the atmosphere from anthropogenic sources in 2010 and future scenarios. Atmospheric Environment, 123, 245–254.
- World Health Organization (WHO). (2017). Mercury environmental health fact sheet.