Los Angeles Reservoir Uses 96 Million Black Balls: Here’s Why

In a bid to tackle a chemical reaction turning bromide into carcinogenic bromate, Los Angeles has released 96 million black plastic balls into its reservoir. Originally intended as a deterrent for birds at airports, these ‘shade balls’ have found a new purpose in ensuring water safety.

Los Angeles has employed an innovative solution to ensure the safety of its drinking water. The city released 96 million black balls into its reservoir. These ‘shade balls’ were originally designed to deter birds from landing on water surfaces, making them particularly useful around airports​¹​. Contrary to popular belief, their primary role isn’t to minimize evaporation but to block sunlight. The sunlight triggers a chemical reaction that turns harmless bromide in the water into a carcinogenic substance called bromate.

Bromide, a natural component of salt water, is safe for humans. However, issues arise when this salty water enters the reservoir and undergoes treatment with the rest of LA’s drinking water. During this process, bromide can form bromate, which is carcinogenic. The Los Angeles Department of Water and Power had been monitoring bromate levels but noticed unexpected spikes in its presence when water entered the reservoir. When bromide and chlorine are exposed to sunlight, the reaction produces even more bromate than when bromide interacts with ozone.

The black balls, previously termed “bird balls”, emerged as a peculiar yet apt solution. While they were typically used around airports to deter birds from settling in nearby waters, they also proved highly effective in preventing sunlight penetration. Furthermore, these balls have added benefits. Their carbon black color ensures they function for up to a decade without any toxic leakage into the water. Once deployed on the reservoir, treatment plants can reduce chlorine use, which typically combats algae growth that thrives in sunlight. As an added advantage, while their primary purpose was not to deter evaporation, they maintained the water at cooler temperatures, significantly reducing evaporation.

The Situation: The Los Angeles Department of Water and Power introduced 96 million black plastic balls into its reservoir. These balls, known as ‘shade balls’, were originally designed to keep birds away from airport water bodies. Their primary function in the reservoir isn’t for bird deterrence or even primarily for the prevention of evaporation, as many might think. Instead, they are primarily used to prevent sunlight from interacting with the water. This sunlight, when it interacts with the bromide present in the water and the chlorine used for treatment, can trigger a chemical reaction producing bromate, a known carcinogen​

Positive Implications:

1. Water Safety Enhancement: By blocking sunlight, the shade balls prevent the formation of carcinogenic bromate. This ensures that the water remains safe for consumption and meets the health standards set by regulators​
2. Reduction in Evaporation: Even though it wasn’t the primary intention, the shade balls have been found to reduce water evaporation by 80 to 90 percent, which is particularly beneficial for arid regions like Los Angeles​
3. Reduction in Algal Growth: The shade balls help in reducing the growth of algae by blocking sunlight. Algae often thrive in sunlight, and their growth in drinking reservoirs can be problematic. Algal change can make water treatment more challenging and may produce toxins
4. Cost-Effective: The balls are relatively inexpensive and can function effectively for up to a decade without degradation or causing environmental harm​

Negative Implications:

1. Misunderstanding and Public Perception: When the balls were first introduced, there was a general misconception that their primary purpose was to combat evaporation due to drought. Such misunderstandings can lead to misguided public debates and potential resistance to such initiatives​
2. Dependence on Physical Barriers: Relying on physical barriers like shade balls may discourage the exploration of more permanent solutions to water treatment challenges. Over time, newer technologies or methods might emerge that can address the problem more effectively.
3. Environmental Concerns: Even though the balls are designed to last for a long time and are made of materials that are deemed safe, there’s always a concern about the long-term environmental impact of such large-scale use of plastic, especially if they start degrading.
4. Maintenance and Monitoring: Over time, the balls may break or degrade, requiring regular checks and potential replacements. This could lead to added costs and labor in the long run.

In conclusion, while the introduction of shade balls in the Los Angeles reservoir has presented a novel solution to a pressing water safety issue, it’s essential to weigh the long-term benefits against potential challenges. As with many innovative solutions, continuous assessment and adaptation are crucial.

Source: Multiple sources including ScienceAlert, Grunge.com, Roaring Earth, and Wonderful Engineering.