Abstract: The presence of hydrocarbons in water is detected by contacting a water sample with an adsorbent material to extract hydrocarbons from the water sample and then contacting the adsorbent material with a solvent for the hydrocarbons. A developer such as a miscible nonsolvent liquid is mixed into the solvent to produce a test mixture. The turbidity of the test mixture is observed to determine the presence of hydrocarbons in the water sample. The nonsolvent may contain at least 0.5% salt, e.g., at least 1%, preferably 5% salt, and an emulsifier. Turbidity may be measured quantitatively by measuring light scattered at 90.degree. to a test light beam or by visual comparison to a reference scale.

Abstract: A communications port adapter and method for using a communications port of a host computer in polling mode and without interrupts. The communications port adapter includes at least a converter circuit for converting an input signal from a measuring device to frequency, a switching component connected to an output of the converter circuit for transmitting a frequency output signal, and a counter circuit having an input connected to the switching component for receiving the frequency output signal of the converter circuit and an ouput coupled to the communications port of the host computer.

Abstract: The presence of hydrocarbons in soil is detected by immersing a soil sample in a water-miscible solvent capable of dissolving the hydrocarbons to extract hydrocarbons from the soil into the solvent. An aqueous developer is mixed into the solvent to produce a test mixture. The turbidity of the test mixture is observed to determine the presence of hydrocarbons in the soil. The aqueous developer may contain at least 0.5% salt, e.g., at least 1%, preferably 5% salt, and an emulsifier. Turbidity may be measured quantitatively by measuring light scattered at 90.degree. to a test light beam or by visual comparison to a reference scale.

Abstract: The presence of hydrocarbons in soil is detected by immersing a soil sample in a water-miscible solvent capable of dissolving the hydrocarbons to extract hydrocarbons from the soil into the solvent. An aqueous developer is mixed into the solvent to produce a test mixture. The turbidity of the test mixture is observed to determine the presence of hydrocarbons in the soil. The aqueous developer may contain at least 0.5% salt, e.g., at least 1%, preferably 5% salt, and an emulsifier. Turbidity may be measured quantitatively by measuring light scattered at 90.degree. to a test light beam or by visual comparison to a reference scale.