Organophosphate esters

Cholinesterase inhibitor (anti-cholinesterase, ChEI) is a chemical that prevents cholinesterases (ChEs) from breaking down. ACh, which consequently increases the level and duration of action of this neurotransmitter. ChEIs such as organophosphates (esters of phosphoric acid) and carbamates (esters of carbamic acid) - serve as insecticides, pesticides, warfare agents and drugs. 

Nerve agents are organophosphate ester derivatives of phosphoric acid. 

Brandt [200] has extracted tri(nonylphenyl) phosphite (TNPP) from a styrene-butadiene polymer using iso-octane. Brown [211] has reported US extraction of acrylic acid monomer from polyacrylates. Ultrasonication was also shown to be a fast and efficient extraction method for organophosphate ester flame retardants and plasticisers [212]. Greenpeace [213] has recently reported the concentration of phthalate esters in 72 toys (mostly made in China) using shaking and sonication extraction methods. Extraction and analytical procedures were carefully quality controlled. QC procedures and acceptance criteria were based on USEPA method 606 for the analysis of phthalates in water samples [214]. Extraction efficiency was tested by spiking blank matrix and by standard addition to phthalate-containing samples. For removal of fatty acids from the surface of EVA pellets a lmin ultrasonic bath treatment in isopropanol is sufficient [215]. It has been noticed that the experimental ultrasonic extraction conditions are often ill defined and do not allow independent verification. 

Levels of Significant Exposure to Organophosphate Ester Hydraulic Fluids - Inhalation... 

Symptoms and Sites of Acetylcholinesterase Inhibition by Organophosphate Esters... 

Genotoxicity of Organophosphate Ester Hydraulic Fluids In Vitro... 

Log Kow Values for Organophosphate Ester Hydraulic Fluid Components... 

Analytical Methods for Determining Organophosphate Ester Hydraulic Fluids in Biological Samples... 

Some hydraulic fluids have a bland oily smell, while others have no smell. Mineral oil and polyalphaolefin hydraulic fluids are mixtures that have oil in them and will bum. Oil-in-water hydraulic fluids (a special type of mineral oil hydraulic fluid) do not bum because they contain water. Organophosphate ester hydraulic fluids are mostly made without oil and will not bum unless there is a flame directly on them once the flame is removed, these fluids will stop burning. Because they do not bum, organophosphate ester hydraulic fluids are used in airplanes and other places where fires are very undesirable. 

Mineral oil hydraulic fluids are produced from crude oil. Organophosphate ester and polyalphaolefin hydraulic fluids are manufactured. All hydraulic fluids contain many ingredients which reduce wear, make the fluid flow better, and make it thinner when it is cold. More than 200 million gallons of hydraulic fluids are sold each year in the United States. See Chapters 3 and 4 for more information on hydraulic fluids. 

Very little is known about how mineral oil hydraulic fluids, polyalphaolefin hydraulic fluids, and organophosphate ester hydraulic fluids enter and leave your body. Some information exists about how some of the chemical components in the organophosphate ester hydraulic fluids enter and leave your body. 

We know that chemical components of mineral oil hydraulic fluids can enter the body if you swallow them or they come in contact with your skin because health effects have occurred in people after they swallowed or had prolonged skin contact with certain mineral oil hydraulic fluids. Health effects have occurred in animals after they breathed, swallowed, or had skin contact with organophosphate ester hydraulic fluids. We do not know if mineral oil hydraulic fluids or polyalphaolefin hydraulic fluids will enter your body from your lungs if you breathe them as vapor or oil mist. 

Cows eating grass containing organophosphate ester hydraulic fluid had difficulty producing milk for their young. We do not know if this will also occur in people. We do not know if organophosphate ester hydraulic fluids will cause birth defects, affect fertility, or cause cancer. 

Hydraulic fluids themselves cannot be measured in blood, urine, or feces, but certain chemicals in them can be measured. Aliphatic hydrocarbons, which are major components of mineral oil hydraulic fluids and polyalphaolefin hydraulic fluids, can be detected in the feces. Certain components of organophosphate ester hydraulic fluids leave the body in urine. Some of these fluids inhibit the enzyme cholinesterase. Cholinesterase activity in blood can be measured. Because many other chemicals also inhibit cholinesterase activity in blood, this test is not specific for organophosphate ester hydraulic fluids. This test is not available at most doctor s offices, but can be arranged at any hospital laboratory. See Chapters 2 and 6 for more information. 

Organophosphate esters are among the most widely used classes of synthetic compounds in hydraulic fluids. They are used as anti-wear additives in mineral oil hydraulic fluids and are significant components in certain fire-resistant hydraulic fluids (FMC 1991c, 1991d, 1992a, 1992b Wills 1980). 

The number of organophosphate esters and similar compounds used in hydraulic fluids is considerable. A core number (approximately 10) have been studied to some degree for toxicity. Though many hydraulic... 

The NOAEL and LOAEL values for each effect after inhalation exposure are shown in Tables 2-1, 2-2, and 2-3 and plotted in Figures 2-1, 2-2, and 2-3 for mineral oil hydraulic fluids, organophosphate ester hydraulic fluids, and polyalphaolefin hydraulic fluids, respectively. 

---