Parts per million ppm

Water separated from oil usually contains small amounts of oil which have to be removed before the water can be released to the environment. Specifications are getting tighter but standards ranging from 10-100 ppm (parts per million) oil in wafer before disposal are currently common. In most areas 40 ppm of oil in water is the legal requirement, i.e. 40 mg / litre. 

Product quality is not limited to oil and gas quality certain effluent streams will also have to meet a legal specification. For example, in disposal of oil in water, the legislation in many offshore areas demands less than 40 ppm (parts per million) of oil in water for disposal into the sea. In the UK, oil production platforms are allowed to flare gas up to a legal limit. 

Of the surface of the earth, 71% (3.60 x 10 km ) is covered by oceans their average depth is 6 km and their volume is 8.54 x 10 km . Unfortunately, this huge quantity of water is not suitable for very many human uses. Water with over 1000 ppm (parts per million by weight, or mg/L) salt is usually considered unfit for human consumption, and water with over 500 ppm is considered undesirable, but ia some parts of the world, people and land animals are forced to survive with much higher concentrations of salts, sometimes of over 2500 ppm. 

Contrary to lUPAC conventions, chemical shifts 5 in this book are scaled in ppm in the spectra, thus enabling the reader to differentiate at all times between shift values (ppm) and coupling constants (Hz) ppm (parts per million) is in this case the ratio of two frequencies of different orders of magnitude, Hz / MHz =1 10 without physical dimension... 

Test a hypothesis about the source of the problem, such as checking emissions from a piece of equipment. Testing for "indicator" compounds associated with particular types of building conditions Peak carbon dioxide CO2) concentrations over 1000 ppm (parts per million) are an indicator of underventilation. Carbon monoxide (CO) over several ppm indicates inappropriate presence of combustion by-products (which may also account for high CO2 readings). Compare any measured concentrations to guidelines or standards. 

Mg/L Milligrams per liter = ppm (parts per million) - expresses a measure of the concentration by weight of a substance per unit volume. 

TLVs are ealeulated using ppm (parts per million by volume), mg/ m (mg of vapor per eubie meter of air). For vapor, mg/m is eon-verted to ppm by the equation ... 

TDS Total dissolved solids, expressed as ppm (parts per million) or as mg/1 (milligrams per liter). Evaporate the water from a sample and the residue can be weighed. TSS Total suspended solids expressed in similar terms to TDS but representing a concentration of insoluble particles. 

Example 6.6 The hardness of water in Coventry is given as a maximum of 560 ppm (parts per million) and the water treatment can permit a concentration of solids to 1200 ppm. The cooling capacity is 700 kW and the compressor power 170 kW. How much water should be bled to waste and what is the total make-up required ... 

The requirements placed on the performance and reliability of CVD coatings are continuously upgraded. For one thing, this means the need for an ever increasing degree of purity of the precursor materials since impurities are the maj or source of defects in the deposit. The purity of a gas is expressed in terms of nines, for instance, six nines, meaning a gas that is 99.9999% pure, which is now a common requirement. It is also expressed in ppm (parts per million) or ppb (parts per billion) of impurity content. 

For all natural waters, boron is one of their constituents with varying concentrations from minute traces to several ppm (parts per million). It is essential for plant growth but is exceedingly toxic at concentration slightly above optimum. Boron tolerances vary depending upon climate, and crop varieties. Relative boron tolerances of agricultural crops are presented in Table 3 [12]. 

The concentration can be expressed in ppm (parts per million) and thus make a direct comparison with the limiting or average explosive values (LEV or AEV) that are often given in ppm. This calculation will enable us to know if the regulations and recommendations are conformed to for the substances. 

The units are preferably ppm (parts per million in volume) for LC50 mg/l for gas and vapour mg/m3 or g/m for aerosols or non-volatile solids that can form suspensions in air. For gas and vapour mg/l is used for the reason that will be explained later. For LD50 use of mg/kg is customary. It goes without saying that the animal genus must be named in all cases. 

One possible location is a site near the source of the raw materials. This location should always be one of the sites considered. If a plant is to recover bromine from sea water it will obviously be placed next to the sea. The bromine concentration of sea water is 60 to 70 ppm (parts per million). It is obviously more expensive to transport 1,000,000 pounds of water than 70 pounds of bromine. Whenever the quantity of the product is small compared with the amount of raw materials, the site is placed near the material source. 

LOAEL=lowest-observed-adverse-effeet level NOAEL=no-observed-adverse-effeet level ppm=parts per million hr = hour derm/oc = dermal/ocular min = minute occup = occupational d = day wt = weight Resp = respiratory Gd = gestation day yr = year hemato = hematological CEL = cancer effect level. 

AEGL-1 is the airborne concentration (expressed as ppm (parts per million) or mg/m3 (milligrams per cubic meter)) of a substance above which it is predicted that the general population, including susceptible individuals, could experience notable discomfort, irritation, or certain asymptomatic nonsensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure. 

Abbreviations ppm, parts per million mg/m3, milligrams per cubic meter. 

The plant produced pesticides. An intermediate compound in this process is methyl isocyanate (MIC). MIC is an extremely dangerous compound. It is reactive, toxic, volatile, and flammable. The maximum exposure concentration of MIC for workers over an 8-hour period is 0.02 ppm (parts per million). Individuals exposed to concentrations of MIC vapors above 21 ppm experience severe irritation of the nose and throat. Death at large concentrations of vapor is due to respiratory distress. 

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