Abstract: Mercury, a ubiquitous environmental pollutant, poses significant risks to human health, including nephrotoxicity. This review aims to provide a comprehensive overview of the association between mercury exposure and nephrotoxicity, encompassing epidemiological evidence, underlying mechanisms, and clinical implications. Epidemiological studies have consistently reported associations between mercury exposure and various markers of renal dysfunction and injury.

Mechanistic studies have elucidated oxidative stress, inflammation, and mitochondrial dysfunction as key pathways underlying mercury-induced nephrotoxicity. Clinical manifestations of mercury nephrotoxicity range from subclinical renal impairment to acute kidney injury and chronic kidney disease. Early detection and mitigation of mercury exposure are crucial for preventing renal damage and mitigating the burden of nephrotoxicity. Future research should focus on clarifying dose-response relationships, identifying susceptible populations, and exploring interventions to prevent or ameliorate mercury-induced nephrotoxicity.

Keywords: Mercury, nephrotoxicity, renal dysfunction, kidney injury, oxidative stress, inflammation

Introduction

Mercury is a naturally occurring element that exists in various forms, including elemental (or metallic), inorganic, and organic mercury compounds. While mercury has industrial and medical applications, its widespread use has led to environmental contamination and human exposure, primarily through consumption of contaminated fish and seafood, occupational exposure, and proximity to industrial sources [1]. Mercury is recognized as a potent toxicant, with adverse effects on multiple organ systems, including the central nervous system, cardiovascular system, and kidneys [2].

Nephrotoxicity refers to kidney damage or dysfunction caused by exposure to nephrotoxic agents, including heavy metals such as mercury. Mercury-induced nephrotoxicity has been documented in both experimental studies and human populations, with manifestations ranging from subclinical renal impairment to acute kidney injury (AKI) and chronic kidney disease (CKD) [3]. The kidneys play a crucial role in regulating fluid and electrolyte balance, excreting waste products, and maintaining acid-base homeostasis. Therefore, impairment of renal function can have profound implications for overall health and wellbeing.

This review aims to provide a comprehensive overview of the association between mercury exposure and nephrotoxicity, encompassing epidemiological evidence, underlying mechanisms, and clinical implications. Understanding the mechanisms of mercury-induced nephrotoxicity is essential for developing preventive strategies and therapeutic interventions to mitigate the adverse effects of mercury exposure on kidney health.

Epidemiological Evidence: Epidemiological studies have consistently reported associations between mercury exposure and various markers of renal dysfunction and injury. These include abnormalities in renal function tests such as serum creatinine, estimated glomerular filtration rate (eGFR), and urinary biomarkers of kidney injury such as albuminuria, proteinuria, and renal

tubular dysfunction [4]. Several population-based studies have demonstrated dose-response relationships between mercury exposure and the prevalence or incidence of CKD, suggesting a causal relationship [5]. Moreover, vulnerable populations such as children, pregnant women, and individuals with pre-existing kidney disease may be particularly susceptible to the nephrotoxic effects of mercury [6].

Mechanisms of Mercury-Induced Nephrotoxicity: The mechanisms underlying mercury- induced nephrotoxicity are complex and multifactorial, involving oxidative stress, inflammation, mitochondrial dysfunction, and direct cellular damage [7]. Mercury has a high affinity for sulfhydryl (-SH) groups in proteins, leading to disruption of enzymatic function and cellular signaling pathways. Reactive oxygen species (ROS) generated during the metabolism of mercury can induce oxidative stress, resulting in lipid peroxidation, DNA damage, and mitochondrial dysfunction [8]. In addition, mercury can activate pro-inflammatory pathways and promote the release of inflammatory cytokines, contributing to renal inflammation and tissue injury [9]. Furthermore, mercury can directly target renal tubular epithelial cells, leading to cell death, necrosis, and apoptosis [10].

Clinical Manifestations: Clinical manifestations of mercury nephrotoxicity vary depending on the duration, route, and dose of exposure. Acute exposure to high levels of mercury vapor or inorganic mercury salts can cause fulminant AKI, characterized by oliguria, proteinuria, hematuria, and acute tubular necrosis [11]. Chronic exposure to lower levels of mercury, such as through dietary intake of methylmercury-contaminated fish, may lead to progressive renal impairment and CKD [12]. Long-term exposure to mercury has also been associated with an increased risk of hypertension, cardiovascular disease, and other adverse health outcomes, further exacerbating the burden of renal disease [13].

Prevention and Management: Preventing mercury exposure is the most effective strategy for reducing the risk of mercury-induced nephrotoxicity. This includes minimizing occupational exposure to mercury vapors and fumes, educating the public about the sources of mercury contamination in the environment, and implementing regulations to limit mercury emissions from industrial processes [14]. Additionally, dietary interventions, such as consuming fish low in mercury and avoiding mercury-containing herbal remedies, can help reduce the risk of mercury toxicity [15]. In cases of acute mercury poisoning, prompt medical intervention is necessary to prevent irreversible kidney damage and systemic toxicity. Treatment may involve supportive measures such as hydration, diuresis, and chelation therapy to enhance mercury elimination [16].

Future Directions: Future research should focus on elucidating dose-response relationships between mercury exposure and nephrotoxicity, identifying susceptible populations, and exploring interventions to prevent or ameliorate the adverse effects of mercury on kidney health. Longitudinal cohort studies are needed to assess the long-term renal effects of chronic low-level mercury exposure and to identify early biomarkers of nephrotoxicity. In addition, experimental studies using animal models can help elucidate the underlying mechanisms of mercury-induced nephrotoxicity and evaluate the efficacy of novel therapeutic agents in mitigating renal damage.

Conclusion

Mercury exposure is associated with nephrotoxicity, as evidenced by epidemiological studies, mechanistic research, and clinical observations. The nephrotoxic effects of mercury are mediated by oxidative stress, inflammation, mitochondrial dysfunction, and direct cellular damage. Preventing mercury exposure and implementing early intervention strategies are essential for mitigating the burden of mercury-induced nephrotoxicity and preserving kidney health. Future research should focus on clarifying dose-response relationships, identifying susceptible populations, and exploring interventions to prevent or ameliorate the adverse effects of mercury on kidney function.

References:

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2. Bridges CC, Zalups RK. Molecular and ionic mimicry and the transport of toxic metals. Toxicol Appl Pharmacol. 2005;204(3):274-308.
3. Yang Q, Ren L, Chen H, et al. Epidemiological evidence on the relationship between exposure to mercury and renal effects in the general population: A systematic review. Environ Res. 2019;177:108620.
4. Guo C, Wang Q, Li R, et al. Mercury-induced toxicity of rat cortical neurons is mediated through N-Methyl-D-Aspartate receptors. Mol Neurobiol. 2016;53(9):6046-58.
5. Xu B, Wu J, Liang J, et al. Renal mechanism and treatment of mercury poisoning. Environ Toxicol Pharmacol. 2019;68:24-33.
6. Leong CC, Syed Mohamed AF, Tan SC, et al. Mercury exposure in a coastal community from consumption of marine fish. J Environ Sci. 2018;68:64-71.
7. Cerna M, Krskova A, Cejchanova M, et al. Markers of renal function in children living in a region with increased environmental burden of heavy metals. Neuro Endocrinol Lett. 2006;27 Suppl 2:26-29.
8. Farina M, Aschner M, Rocha JB. Oxidative stress in MeHg-induced neurotoxicity. Toxicol Appl Pharmacol. 2011;256(3):405-17.
9. Mutter J, Curth A, Naumann J, et al. Does inorganic mercury play a role in Alzheimer’s disease? A systematic review and an integrated molecular mechanism. J Alzheimers Dis. 2010;22(2):357-74.
10. Bernhoft RA. Mercury toxicity and treatment: A review of the literature. J Environ Public Health. 2012;2012:460508.

11.WHO. Mercury and health. World Health Organization. https://www.who.int/news- room/fact-sheets/detail/mercury-and-health. Accessed March 18, 2024.

12. United States Environmental Protection Agency (EPA). Mercury: Human Exposure. https://www.epa.gov/mercury/mercury-human-exposure. Accessed March 18, 2024.
13. Järup L, Åkesson A. Current status of cadmium as an environmental health problem. Toxicol Appl Pharmacol. 2009;238(3):201-8.
14. Cherian MG, Hursh JB, Clarkson TW, et al. Clearance of mercury (Hg-197, Hg-203) vapor inhaled by human subjects. Arch Environ Health. 1978;33(3):109-14.
15. Sallsten G, Barregård L, Schütz A. Clearance half life of mercury in urine after the cessation of long term occupational exposure: Influence of a chelating agent (DMPS) on excretion of mercury in urine. Occup Environ Med. 1994;51(5):337-42.
16. Sjögren B, Gustavsson H, Lundh T, et al. Mercury exposure in chloralkali plants in Sweden: Exposure from metallic mercury vapor and inorganic mercury in urine. Occup Environ Med. 1994;51(4):245-50.

Mercury exposure has emerged as a pressing public health issue for residents residing in galamsey- prone regions of Ghana. Galamsey, characterized by illegal small-scale mining operations, often employs mercury to extract gold from ore. Unfortunately, this practice results in the significant release of mercury into the environment, contaminating water sources and soils. Consequently, plants absorb this mercury, leading to the contamination of the food chain.

Individuals in these areas face a heightened risk of mercury accumulation in their bodies through various routes, including consuming foods grown in contaminated soils, inhaling mercury vapors, ingesting water and fish with mercury levels, and absorbing mercury through the skin. Numerous studies have linked prolonged mercury exposure to various health issues, notably kidney failures.

Mercury gradually accumulates in the body, particularly in the kidneys, impairing their function and potentially causing renal complications. Since kidneys are vital for filtering waste from the bloodstream, mercury exposure can damage these organs, disrupting fluid and electrolyte balance and impairing filtration and waste elimination.

However, can the surge in galamsey activities in our country be attributed to the increased incidence of kidney failures? Preliminary findings from a major teaching hospital in Ghana suggest that 8 out of every 10 kidney patients that visit their hospital for dialysis originate from galamsey communities or are dependent on it. Historically, Ghana has experienced low levels of kidney cases, possibly due to limited engagement in illegal mining activities like galamsey.

Addressing this issue demands a multifaceted approach, including stringent regulations on illegal mining, improved waste management practices, and heightened awareness among affected communities regarding the dangers of mercury exposure. Furthermore, healthcare interventions should prioritize early detection and management of kidney problems among individuals residing in galamsey-prone areas.

In conclusion, mercury exposure stemming from illegal mining activities poses a significant health hazard to residents, particularly concerning kidney failures. Combating this issue requires a comprehensive strategy encompassing environmental regulations, community education, and healthcare interventions to safeguard the well-being of affected individuals.

Let us unite against this menace and recognize that it affects us all, as we may unwittingly consume contaminated products from the food chain. Additionally, other risk factors for kidney failure, such as certain medications, herbal products, and lifestyle factors, should also be considered and addressed in prevention and intervention efforts.

Yakubu Adam
FIND-GH (Forensic Investigation for National Development-GH) Toxicologist/Lecturer
+233543494865
[email protected]

In the fast-paced and highly competitive sport of soccer, referees play a crucial role in maintaining order and fairness on the field. One of their most significant decisions is whether to issue a yellow or red card to a player for a foul or misconduct. This article explores the criteria and considerations referees use to make this decision, highlighting the importance of consistency, fairness, and adherence to the game’s rules. Use your 1xBet paybill number to deposit funds if you want to win big. 

Understanding the Difference:

Before delving into how judges decide between yellow and red cards, it’s essential to understand the distinction between the two penalties. A yellow card serves as a warning to a player for committing a foul or an act of misconduct. It indicates that the player has committed a relatively minor offense and is a cautionary measure to prevent further infractions. On the other hand, a red card signifies a more severe offense, resulting in the player’s ejection from the game. Red cards are typically issued for severe fouls, violent conduct, or repeated misconduct.

Factors Considered by Referees:

Referees must assess several factors when determining whether to issue a yellow or red card. These factors include:

• The severity of the Foul: Judges evaluate the severity of the foul committed by the player. Minor infractions, such as a mistimed tackle or a tactical foul, may warrant a yellow card. However, tackles that endanger the safety of an opponent or involve excessive force are more likely to result in a red card.
• Intent: Referees consider the intent behind the player’s actions. Accidental fouls or those committed in the heat of the moment are less likely to result in a red card than deliberate acts of aggression or violent conduct.
• Recklessness: Referees also assess whether the player acted recklessly or with disregard for the safety of others. Regardless of intent, reckless challenges can lead to severe injury and may warrant a red card, especially if they involve excessive force or endanger an opponent.

• Previous Offenses: A player’s disciplinary record is considered when deciding on the appropriate sanction. Repeat offenders are more likely to receive harsher penalties, including red cards, as referees aim to deter misconduct and maintain discipline on the field.
• Impact on the Game: Judges consider the potential impact of their decision on the outcome of the game. Issuing a red card can significantly alter the dynamics of a match, mainly if it results in a team playing with fewer players. Therefore, referees strive to balance enforcing the rules and ensuring fair competition.
• Consultation with Assistant Referees: In some cases, referees may consult with their assistant linesmen or utilize video review technology to aid their decision-making process. This additional input helps ensure that the correct decision is made, mainly when the jusge’s view may have been obstructed or unclear.

Consistency and Fairness:

Consistency and fairness are paramount in the referee’s decision-making process. Judges strive to apply the game rules uniformly throughout the match, regardless of the teams involved or the stage of the competition. Consistent enforcement of the rules helps maintain the integrity of the game and ensures that players understand the consequences of their actions.

Conclusion:

In conclusion, deciding to issue a yellow or red card is a critical responsibility for soccer referees. By considering factors such as the severity of the foul, the player’s intent, and the potential impact on the game, referees strive to make fair and consistent decisions that uphold the spirit of the sport. Ultimately, the goal is to maintain order, ensure player safety, and uphold the integrity of the game of soccer.