ENVS CHEM

BTEX is an acronym that stands for benzene, toluene, ethylbenzene, and xylenes. These compounds are some of the volatile organic compounds (VOCs) found in petroleum derivatives such as petrol (gasoline). Toluene, ethylbenzene, and xylenes have harmful effects on the central nervous system.

• Commonly called Freons; very stable and non-toxic, used in
• flexible and rigid foams and was fluids for refrigeration and air conditioning.

CFCs have been implicated in the accelerated depletion of ozone in the Earth's stratosphere. HCFCs has been use to replace CFCs, H-C bonds in HCFCs are easilybroken by atmospheric reactions with hydroxyl radical before they can reach the stratosphere.

• Carbon monoxide (CO), aka carbonic oxide, is a colorless, odorless and
• tasteless gas which is lighter than air. Product of incomplete combustion; combines
• with hemoglobin to form carboxyhemoglobin, poisonous.

Hydrogen sulfide is a colorless, very poisonous, flammable gas with the characteristic foul odor of rotten eggs. It often results from the bacterial breakdown of organic matter in the absence of oxygen, such as in swamps and sewers (anaerobic digestion). It also occurs in volcanic gases, natural gas, and some well waters. The body produces small amounts of H2S and uses it as a signaling molecule.

• Sedimentation in inertia
• Filtration
• Scrubbers
• Electrostatic removal

• A group of fibrous silicate minerals, known for tensile strength, flexibility, and non-flammability. Uses include structural material, brake lining, insulation and pipe manufacture. In 1989 EPA implemented regulations phasing out most uses by 1996.
• Health effects of Asbestos exposures: Asbestosis(a pneumonia-like condition), Mesothelioma (a tumor of the lining of the chest cavity), and Bronchogenic carcinoma. 

• highly reactive;
• produced during the formationof photochemical smog;
• damage to vegetation and property.
• Use of CFCs cause a stratosphere ozone depletion, HCFCs has been use to replace CFCs, H-C bonds in HCFCs are easilybroken by atmospheric reactions with hydroxyl radical before they can reach the stratosphere.

• Brown to orange gas; Important
• component of photochemical smog and acidic deposition.

• colorless and odorless, formed during complete combustion;
• may cause “greenhouse effect” and climate change.

• Colorless, choking gas, soluble in water to form sulfurous acid H2SO3.
• Main component acidic deposition; damage to vegetation, materials, health.
• Found mostly in the north eastern part of the US because of coal and steel factories.

colorless gas, produced during high temperature combustion. Readily oxidized to NO2.

Acid rain is rain or any other form of precipitation that is unusually acidic, i.e. elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals, and infrastructure through the process of wet deposition. Acid rain is caused by emissions of compounds of ammonium, carbon, nitrogen, and sulfur which react with the water molecules in the atmosphere to produce acids.

Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide. Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain.

There are two major species of mercury in water column. Hg and MeHg. MeHg is the major species that is accumulated in the food web, causing a potential human health problem.

There are also reduction processes by phytoplankton and bacteria. Elemental Hg is the major species that diffuses out of water, and mercuric mercury (Hg(II)) is the major species of Hg that precipitates back to water.

Hg and MeHg are particle reactive, and interact with particulate material in water column. Hg and MeHg also interact with colloids.

(Adsorption of Hg onto colloidalmaterial is relatively fast, and coagulation processes are kinetically slow. Processes in which the solution phase transforms to the particulate phase via the colloidal phase is referred as “Colloidal Pumping”. One of the major objectives in this study is to measure colloidal MeHg concentrations in natural waters.)

Particulate Hg is scavenged to sediments. The sediment is a major place where Hg methylation processes are occurred by sulfate reducing bacteria. Hg could also precipitate as mercuric sulfide.

Methylation/demethylation of inorganic Hg in waters and sediments is a key step in the cycling of Hg in aquatic systems, and takes place in both remote and impacted environments. These processes determine MMHg concentration in the environment, and hence eventually determine the MMHg level in Fish.

complex mixture of varying composition.

•Class A – Light, volatile oils; Often colorless, very fluid; Strong odor, high evaporation rate; highly toxic; Most refined products and high quality light crude; Jet Fuels, gasoline

•Class B – Non-Sticky oils; Oily or waxy feel; Adhere more firmly than Class A; less toxic than Class A; Medium to heavy paraffin based oils; Diesel, No. 2 fuel oil, light crude

• •Class C – Heavy, Sticky oils
• •Class D – Non fluid oils

•Balvia de Campeche, Mexico

• Offshore rig explosion, June 3,1979

• 5880 billion gallons spilled

• Prevailing summer currents in Gulf of Mexico

• Effects seen in Texas through August 1980

• Depend on physical and chemical characterstics.
• Ingestion
• Inhalation
• Dermal contact
• Bioconcentration through food chain

• Humans: Occupational related diseases; Leukemia; Dermatitis, acne
• Birds: Oil disrupts finestructure of feather, loss of water repellency and decreased body insulation.
• Marine mammals: Inhalation, surficial contact and ingestion; absorption by the circulation system, irritation and permanent damage to mucus membrane.
• Zooplanktons: altered swimming performance, increased breathing rates, reduced survival rate and
• morphological abnormalities.

• The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Infrared radiation (IR) is electromagnetic radiation with a wavelength between 0.7 and 300 micrometres, which equates to a frequency range between approximately 1 and 430 THz. Its wavelength is longer (and the frequency lower) than that of visible light, but the wavelength is shorter (and the frequency
• higher) than that of terahertz radiation microwaves.

• • v = settling velocity
• • g = acceleration of gravity
• • r1 = particle density
• • r2 = air density
• • n2 = air viscosity

• 300mi-beyond Exosphere
• 50-300mi Thermosphere (aurora /meteors)
• 30-50mi Mesosphere
• 6-30 mi Stratosphere (ozone layer)
• 0-6 mi Troposphere

• Normal range 1-3% by volume
• Vapor responsible for atmospheric temperature stability
• Hydrologic cycle
• Crucial in atmospheric energy transfer
• Tropopause prevents water vapor transfer from troposphere to
• stratosphere

• Peter Laut then used another method to explain other aspects of the
• greenhouse effect, showing what happens to 100 units of sunshine entering the
• Earth’s atmosphere.

• Out of 100 units, 22 units are reflected by clouds, 8 units are reflected by
• the Earth’s surface, 20 units are absorbed by the atmosphere, and the remaining
• 50 units reach the ground, where they are converted to heat.

• For the temperature to remain stable, the Earth has to rid itself of these
• 50 units and this is done in the following way: 7 units are taken into the
• atmosphere by thermal winds, 23 units are absorbed by the atmosphere through
• evapo-transpiration, and the last 20 units leave the Earth as radiation.

• The problem is that the last 20 units are made up of a balance between
• surface radiation eminating from the Earth and back radiation reentering the
• surface thanks to the mechanism of the greenhouse gases described previously.
• The balance maintained by the Earth’s climate system during the previous 10,000
• years of stable climate has been 115 units leaving the surface and 95
• re-entering, thus creating a surplus of 20 units.

• The man-made increase in the amounts of greenhouse gases
• means that the amount re-entering the surface has also increased from the old
• equilibrium value of 95 units, causing temperatures to rise.

Where

• De is the aerodynamic equivalent diameter.
• D is the actual diameter.
• B is the aspect ratio (length / diameter) of the fiber.

• This equation has an important bearing on the respirability of fibers and on their ability to drift in the
• air.



FDA and EPA issued a joint consumer advisory about mercury in fish and shellfish. The advice is for: women who might become pregnant; women who are pregnant; nursing mothers; and young children. This is the first time FDA and EPA have combined their advice into a single uniform advisory. Previously FDA issued an advisory on consumption of commercially caught fish, while EPA issued advice on recreationally caught fish.



The greenhouse effect is associated with the absorption and reradiation of energy by atmospheric greenhouse gases and particles, resulting in a downward flux of infrared radiation from the atmosphere to the surface (back radiation) and therefore in a higher surface temperature. Note that the total rate at which energy leaves Earth (107 W/m2 of reflected sunlight plus 235 W/m2 of infrared [long-wave] radiation) is equal to the 342 W/m2 of incident sunlight. Thus Earth is in approximate energy balance in this analysis.