A river is contaminated with 0.83 mg/L of dichloroethylene (C2H2Cl2). What is the concentration (in ng/L) of d?

A river is contaminated with 0.83 mg/L of dichloroethylene (C2H2Cl2). What is the concentration (in ng/L) of dichloroethylene at 19°C in the air breathed by the people sitting along the riverbank (kH for C2H2Cl2 in water is 0.033 mol/L·atm)?

3 Answers

  • 1 decade ago
    Favorite Answer

    Although you left out SO many variables: rate of descent of the river in topographical number of degrees, the width/depth of the river, the temperature of the water and the flow of a river is NOT constant. Longitude and latitude, as location plays a huge factor, whether it's day or night, and if the weather is fair, cloudy or raining or snowing..... So, here's the lowdown:

    The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for 1,2-dichloroethylene is 200 ppm (790 milligrams per cubic meter (mg/m(3)) as an 8-hour time-weighted average (TWA) concentration [29 CFR 1910.1000, Table Z-1].


    The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for 1,2-dichloroethylene of 200 ppm (790 mg/m(3)) as a TWA for up to a 10-hour workday and a 40-hour workweek [NIOSH 1992].


    The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned 1,2-dichloroethylene a threshold limit value (TLV) of 200 ppm (793 mg/m(3)) as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 18].

    * Rationale for Limits

    The NIOSH limit is based on the risk of narcotic effects and mucous membrane irritation [NIOSH 1992].

    The ACGIH limit is based on the no-effect level of 1,000 ppm in animals [ACGIH 1991, p. 430].


    * Routes of Exposure

    Exposure to 1,2-dichloroethylene can occur through inhalation, ingestion, and eye or skin contact [Sittig 1991].

    * Summary of toxicology

    1. Effects on Animals: 1,2-Dichloroethylene vapor is a central nervous system depressant and a mild irritant of the mucous membranes [ACGIH 1991; Hathaway et al. 1991]. The acute oral LD(50) for a 60:40 cis-trans mixture in rats is reported as greater than 2,000 mg/kg [Clayton and Clayton 1982]. Inhalation exposure to 16,000 ppm for 4 hours was lethal to rats, but 8-minute exposures to the same concentration produced anesthesia [Clayton and Clayton 1982]. Chronic exposure studies have shown that repeated inhalation of up to 1,000 ppm dichloroethylene resulted in no identified ill effects in rats, rabbits, guinea pigs, and dogs [ACGIH 1991; Hathaway et al. 1991]. Dogs narcotized by inhaling 1,2-dichloroethylene vapor developed superficial corneal turbidity that cleared within 48 hours and did not disturb vision [Grant 1986].

    2. Effects on Humans: The major effect of 1,2-dichloroethylene is narcosis; it has been used in a combination with ether (Dichloren) as an anesthetic in at least 2000 cases. No evidence of eye toxicity was seen in these cases [Grant 1986]. In high concentrations, exposure to 1,2-dichloroethylene causes central nervous system depression; in milder exposures, it can produce nausea, vomiting, weakness, tremor, epigastric cramps, burning of the eyes and vertigo [Gosselin 1984; Hathaway et al. 1991]. One fatality has been reported that was due to inhalation of a very high vapor concentration in a small enclosure [Hathaway et al. 1991].

    * Signs and symptoms of exposure

    1. Acute exposure: Exposure to the vapor of dichloroethylene may cause burning of the eyes. Other symptoms of acute exposure are nausea, vomiting, and epigastric distress. Symptoms of exposure-related narcosis including drowsiness, tremor, incoordination, dizziness, and weakness; these symptoms clear quickly after exposure is terminated.

    2. Chronic exposure: 1,2-Dichloroethylene is a defatting agent, and repeated skin exposure may cause irritation and dermatitis.


    * Emergency medical procedures: [NIOSH to supply]

    5. Rescue: Remove an incapacitated worker from further exposure and implement appropriate emergency procedures (e.g., those listed on the Material Safety Data Sheet required by OSHA's Hazard Communication Standard [29 CFR 1910.1200]). All workers should be familiar with emergency procedures, the location and proper use of emergency equipment, and methods of protecting themselves during rescue operations.


    The following operations may involve 1,2-dichloroethylene and lead to worker exposures to this substance:

    * The manufacture and transportation of 1,2-dichloroethylene

    * Use as a low-temperature extraction solvent for heat-sensitive substances (caffeine, perfume oils, and fats from fish and meat) and in dye extraction.

    * Use as a general solvent of gums, rubber, waxes, oils, camphor, phenol, esters, ether derivatives, acetyl cellulose, lacquers, resins, thermoplastics, artificial fibers, and organic materials.

    * Use as a chemical intermediate in the synthesis of polymers, telomers, and chlorinated solvents and compounds.

    * Use in miscellaneous applications as dry cleaning agent, cleaning solution for printed circuit boards, food packaging adhesives, germicidal fumigants, and in retarding fermentation.

    * Use as a refrigerant and coolant and in the manufactur

    Source(s): There would be NO significant amount C2H2Cl2 in the atmosphere or the river to affect any of the workers. The atmosphere and the flow of the river would carry it away and it would be quickly dissipated into the water/atmosphere.
  • Nicole
    Lv 4
    5 years ago

    Three ways to answer this. 1.) Obidience and compliance- MIlgrams famous study was provoked by the holocaust. He found, of normal everyday Americans off the street, 60% would continue electricuting some until they died (they believed) if instructed to. The idea is you hand over responsibility to someone of higher rank (a similar thing was applied to the American soilders bombing a villiage of women and children in Vietnam) 2.) Depersonalisation: In any case of genocide, there are a few universal conditions: an us - them attitude towards the percieved underclass, depersonalistion of the perceived underclass (Jews, dark skinned races, homosexuals were considered lesser than the perfect race), blaming them for all the problems, believing that the country is in a state of crisis - an extreme solution is needed, and a strong leader 3.) More recently, psychologists have dismissed Milgram's view at least as it applies to the higher level of the chain of command (it might still apply to you bulldozer driver). Several of the camp guards actively and imagineitively interpreted orders that did not actuall call for the holocaust, orders being very vague. There was an air of competetion for Hitler's favour. The guards were committed to what they were doing, knew what they were doing, and they thought it was the right thing to do. They thought they were killing an enamy, they take on the ideology of the group that condones this behavoir Most of the people that were "responsible" were sentenced at the nuremberg trial. Others lower down were more likely to be (or at least feel) they were just following orders, thus avoiding guilt that would lead them to suicide. Those that took on the ideology would not feel guilt

  • Anonymous
    1 decade ago

    I did the calulations. The answer is 2% plaid.

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