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Population equivalent (PE) or unit per capita loading, or equivalent person (EP), is a parameter for characterizing industrial wastewaters.It essentially compares the polluting potential of an industry (in terms of biodegradable organic matter) with a population (or certain number of people), which would produce the same polluting load.
For methylmercury, the US Environmental Protection Agency (US EPA) has estimated a safe daily intake level of 0.1 μg/kg body weight per day. [ 19 ] The National Institute for Occupational Safety and Health (NIOSH) recommends that exposures to mercury metal be limited to an average of 0.05 mg/m 3 over a 10-hour workday in addition to a ceiling ...
Densities using the following metric units all have exactly the same numerical value, one thousandth of the value in (kg/m 3). Liquid water has a density of about 1 kg/dm 3, making any of these SI units numerically convenient to use as most solids and liquids have densities between 0.1 and 20 kg/dm 3. kilogram per cubic decimetre (kg/dm 3)
The density of surface seawater ranges from about 1020 to 1029 kg/m 3, depending on the temperature and salinity. At a temperature of 25 °C, the salinity of 35 g/kg and 1 atm pressure, the density of seawater is 1023.6 kg/m 3. [7] [8] Deep in the ocean, under high pressure, seawater can reach a density of 1050 kg/m 3 or higher. The density of ...
This is equivalent to about ninety seconds out of one day. One part per ten thousand is denoted by the permyriad sign (‱). Although rarely used in science (ppm is typically used instead), one permyriad has an unambiguous value of one part per 10,000 (10 4) parts, and a value of 10 −4. This is equivalent to about nine seconds out of one day.
In 1901, at the 3rd CGPM conference, the litre was redefined as the space occupied by 1 kg of pure water at the temperature of its maximum density (3.98 °C) under a pressure of 1 atm. This made the litre equal to about 1.000 028 dm 3 (earlier reference works usually put it at 1.000 027 dm 3 ).
Mercury can enter seas and the open ocean as a result of the down stream movement and re-deposition of contaminated sediments from urban estuaries. [12] For example, high total Hg content up to 5 mg/kg and averaging about 2 mg/kg occur in the surface sediments and sediment cores of the tidal River Mersey, UK, due to discharge from historical industries located along the banks of the tidal ...
The term molality is formed in analogy to molarity which is the molar concentration of a solution. The earliest known use of the intensive property molality and of its adjectival unit, the now-deprecated molal, appears to have been published by G. N. Lewis and M. Randall in the 1923 publication of Thermodynamics and the Free Energies of Chemical Substances. [3]