parts per billion

itravler

New Member
chinese
Hey guys ,i am new which means I have a bunch of rediculous quesions.
so... here is the first one :(

In the Wal-Mart and Giant Food bottled water, the highest concentration of chlorine byproducts, known as trihalomethanes, was over 35 parts per billion. California's limit is 10 parts per billion or less, and the industry's International Bottled Water Association makes 10 its voluntary guideline. The federal limit is 80.

parts per billion = what?
 
  • bibliolept

    Senior Member
    AE, Español
    Welcome, itravler.

    "35 parts per billion" means that if you take a sample of water, divide it by volume into one billion pieces/parts, 35 of those will be trihalomethanes. The sample is made up of 35/1,000,000,000 trihalomethanes, or 0.0000035 percent.
    0.000000035
     

    winklepicker

    Senior Member
    English (UK)
    Welcome to WRF, itravler.

    Your question is not at all ridiculous compared to some we have had. :D

    Beware of the two meanings of billion: although I think most countries have now standardised on a thousand million (and certainly that would be true for US companies like those in your example) there is always a possibility of it meaning a million million.
     

    Cheesee = Madness

    Senior Member
    Canadian English
    Welcome to WRF, itravler.

    Your question is not at all ridiculous compared to some we have had. :D

    Beware of the two meanings of billion: although I think most countries have now standardised on a thousand million (and certainly that would be true for US companies like those in your example) there is always a possibility of it meaning a million million.
    Really? I've never heard of that use. Wouldn't a million millions be a trillion?
     
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