Health Risks

Mercury is usually released into the environment by manufactories as emissions or waste. Eventually this mercury is discharged into the water bodies and then is converted by bacteria living in the sediment into methyl mercury. Methyl mercury can be ingested by smaller aquatic plants and animals. The danger here is that, through biomagnification, animals higher in the food chain will have larger concentrations of methyl mercury in their systems. This is dangerous especially for large fish, birds, and humans. Additionally, through bioaccumulation, small amounts of consumed toxins can build up within one’s system over time, leading to mercury poisoning. The most common form of mercury poisoning comes from methyl mercury. According to the Environmental Protection Agency, almost everyone in the world has trace amounts of methyl mercury in their bodies because of its abundance in our environment, but in larger concentrations, it can be dangerous.

Side Effects of Mercury Poisoning:

For infants and children:

• Impaired neurological development
• Impaired cognitive thinking, memory, attention, and language skills
• Impaired fine motor and spatial visual skills

For adults:

• "pins and needles” in the hands, feet, and around the mouth
• impairment of the peripheral vision
• lack of coordination of movements
• impairment of speech and hearing
• muscle weakness

Extreme cases of high mercury poisoning:^[3]

• Kidney and respiratory failure
• Death

Case Studies

According to the Blacksmith Institute’s 2010 report on the world’s worst pollution problems, lead is the world’s number one toxic threat with an estimated global impact of 18 to 22 million people, more than the population of Syria^[11]. Lead has long been in use in numerous industries that manufacture products intended for consumption by average families. Famously, tetraethyl lead was added to gasoline (hence leaded gasoline) to improve its octane rating and to increase longevity of motor vehicle components, a practice that began in the United States in 1923, continued through until regulations saw implementation in the 1970s, finally ending with a zero-tolerance ban through the Clear Air Act in 1996. A 1988 report to Congress by the Agency for Toxic Substances and Disease Registry estimated that 68 million children had toxic exposure to lead from lead gasoline between 1927-1987. ^[7]

Other sources of lead include leaded paint, dust that gathers on lead products, contaminated soil, and others. Since lead cannot be absorbed through contact with skin, the metal must be consumed in some form for it to be toxic. Unfortunately, lead tastes sweet. This means that flaking lead paint or the dust that forms on vinyl blinds imported before 1997 might be consumed repeatedly. In fact, the United States Consumer Product Safety Condition found that if a child ingested dust from less than one square inch of blind a day for about 15 to 30 days they could have blood lead levels at or above 10μg/dL ^[9].

Lead can usually only enter the body through ingestion, which is why pollution of drinking water supplies is of primary concern. When ingested at high enough concentrations, lead can be acutely toxic causing neurological damage and death. In 2008, 18 children in Dakar, Senegal died of acute lead poisoning associated with the recycling of lead car batteries.^[2] Others associated with the recycling facility displayed symptoms ranging from an upset stomach to involuntary convulsions.^[2]

Current Remediation Techniques

Although the EPA is working with the National Institute of Standards and Technology to reduce mercury use and pollution, there are still a number of already contaminated areas that are being remediated now.^[11]
Nitrate Immobilization: The use of calcium nitrate to prevent methyl mercury from moving throughout bodies of water.^[12]
Dredging: Mercury containing sediments are removed or dug up from the lake bottom.^[12]
ISMS (In Situ Mercury Stabilization): Developed by Brookhaven researchers, the ISMS treats and removes mercury content from the soil, sludge, and other industrial waste; therefore stopping mercury from entering the water source.^[13]
Thermal desorption: This involves heating the contaminated soil to high temperatures so that the mercury will vaporize away and can be separated from the soil.^[13]