I took a boat through 96 million black plastic balls on the Los Angeles reservoir to find out why they're there. The first time I heard about shade balls the claim was they reduce evaporation. But it turns out this isn't the reason they were introduced. Huge thanks to LADWP for arranging this special tour for me. Next time let's put the GoPro on the submersible! The balls are made of high density polyethylene (HDPE) which is less dense than water so they float on the surface of the reservoir even if they break apart. They are 10cm (4 inches) in diameter and contain about 210ml of water. So the main reason they are on the reservoir is to block sunlight from entering the water and triggering a chemical reaction that turns harmless bromide into carcinogenic bromate. This effect occurs with prolonged exposure to bromate so regulators insist that levels be kept below 10 microgram per liter on average over a 12 month period.
Date: May 21, 2019 at 08:36:36 From: Awen, [DNS_Address] Subject: Re: Why Are 96,000,000 Black Balls on This Reservoir?
MMmm.....delicious plastic breakdown.
Must be great for the water ecology, too. /s
Note: Can't watch videos from this computer, I'm mainly going by the description you gave, so if there's something about the video that counters my two gripes, then forget what I said. :-)
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Date: May 19, 2019 at 20:56:33 From: Eve, [DNS_Address] Subject: Re: Why Are 96,000,000 Black Balls on This Reservoir?
I saw some of that previously...like whee more plastic just what is needed to not decompose for generations. Might fix short term but cause another issue that lasts longer perhaps.