Case Study: Mercury Exposure Risk Evaluation and a School

Sysco Environmental Ltd conducted a thorough mercury survey to evaluate potential airborne mercury levels resulting from historical use in the Physics 1 Laboratory. Located on the 2nd floor of a building constructed in the early 1900s, both the Physics 1 Laboratory and Physics Prep Room were assessed. The primary aim of the investigation was to determine the health risks associated with possible mercury contamination in these areas.

Mercury has been extensively used in physics laboratories since the early 1900s due to its unique properties, including its high density, liquid state at room temperature, and ability to conduct electricity. These uses, however, also posed risks of contamination, which have been the focus of modern health and safety assessments.

Mercury found widespread use in various laboratory instruments due to its unique properties. It was commonly used in thermometers and barometers because of its high coefficient of expansion and stable liquid state over a wide temperature range. In experiments measuring pressure differences, mercury manometers were essential tools. Mercury's excellent electrical conductivity made it ideal for use in switches, relays, and rectifiers. For creating high vacuum environments necessary for certain experiments, mercury diffusion pumps were employed. In the field of spectroscopy, mercury vapour lamps were valued for their intense emission lines. Additionally, some types of calorimeters utilised mercury for its thermal properties.

Potential Sources of Mercury Contamination

 
The room has been refurbished numerous times since its construction, but due to the lack of regulatory guidance and general knowledge about the risks and decontamination methods, sources of mercury could have been ignored or missed. Potential sources of contamination include:
 
1. Spills and Breakages:
   - Instruments containing mercury, when broken, could release mercury droplets which are difficult to clean up and can remain hidden in cracks and crevices.
   - Even small spills can result in significant contamination over time.
 
2. Vapour Emissions:
   - Mercury can evaporate at room temperature, leading to vapour contamination. Poor ventilation in older laboratories exacerbated this issue.
   - Equipment that heats mercury (such as certain types of lamps and pumps) could release mercury vapour into the air.
 
3. Improper Disposal:
   - Historically, there was less awareness of proper disposal methods for mercury. It was not uncommon for mercury to be discarded in ways that led to contamination of floors and work surfaces.
   - Mercury was sometimes poured down drains, leading to contamination of plumbing and subsequent vapour release.
 
4. Poor Handling Practices:
   - Lack of adequate safety protocols and protective equipment in the early 20th century meant that mercury was often handled without gloves or proper ventilation.
   - Routine laboratory practices might include the casual use of mercury, leading to chronic low-level contamination.

Mercury Vapour Health and Safety Concerns

The expected levels of mercury in such an environment would indeed be low, but even these low levels can represent a substantial risk if the users of the rooms are exposed continuously. Long-term exposure to very low levels of mercury can still lead to significant health implications due to its cumulative toxicity.

Neurologically, it may cause subtle cognitive impairments, mood swings, anxiety, depression, and sensory impairments. Kidney function can also be affected, potentially resulting in mild but chronic kidney dysfunction. The immune system may be disrupted, increasing susceptibility to infections and autoimmune diseases, as well as enhancing allergy sensitivity. Cardiovascular health can be impacted, with slight increases in blood pressure and a higher risk of cardiovascular diseases.

Reproductive health may also suffer, with potential reductions in fertility and subtle reproductive system changes. Pregnant women exposed to low levels of mercury risk developmental delays and cognitive impairments in their children. Additionally, mercury can interfere with the endocrine system, disrupting hormonal balance and affecting metabolism and growth.

General well-being may decline, with symptoms such as chronic fatigue, headaches, muscle aches, and joint pain, which are difficult to directly attribute to mercury exposure.

These subtle and cumulative effects highlight the importance of monitoring and minimizing even low-level mercury exposure to protect long-term health.

 Results of Mercury Contamination Assessment

The results of the mercury survey indicated that all sampled locations, including the Physics 1 Laboratory, Physics Prep Room, teaching staff areas, and technicians' areas, had mercury levels below the limit of detection (LOD). The LOD represents the lowest amount of mercury that can be accurately detected by the analytical method used. This means that the detected mercury levels were so low that they could not be quantified with certainty, indicating that the concentrations present were minimal and well below any significant risk threshold.

All mercury samples were reported as below the limit of detection (LOD). This signifies that the levels of mercury in all sampled locations were lower than the minimum detectable amount, suggesting an extremely low presence of mercury vapours or residues in the environment.
The assessment concluded that the overall risk to health from exposure to mercury is low, as all samples were below the limit of detection.

This finding underscores the minimal risk posed by mercury in the surveyed areas and highlights the effective safety measures in place. Sysco Environmental Ltd's comprehensive evaluation provides valuable assurance of the safety and health of the room users, demonstrating our commitment to thorough and accurate environmental hazard assessments.