Page 72 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Water Contaminants 27

TABLE 2.3
List of Priority Pollutants Regulated by the USEPA
Antimony Toluene Hexachlorobutadiene
Arsenic 1,1,1-Trichloroethane Hexachlorocyclopentadiene
Beryllium 1,1,2-Trichloroethane Hexachloroethane
Cadmium Trichloroethylene Indeno(1,2,3-cd) pyrene
Chromium(III) Vinyl chloride Isophorone
Chromium(IV) 2,4-Dichlorophenol Nitrobenzene
Copper 2-Methyl-4,6-dinitrophenol N-Nitrosodimethylamine
Lead 2,4-Dinitrophenol N-Nitrosodiphenylamine
Mercury Pentachlorophenol Phenanthrene
Nickel Phenol Pyrene
Selenium 2,4,6-Trichlorophenol Aldrin
Silver Acenaphthylene Alpha-BHC
Thallium Anthracene Beta-BHC
Zinc Benzidine Gamma-BCH
Cyanide Benzo[a]anthracene Chlordane
Asbestos Benzo[a]pyrene 4,4 -DDT
0
2,3,7,8-TCDD (dioxin) Benzo[b]fluoranthene 4,4 -DDE
0
Acrolein Benzo[ghi)perylene 4,4 -DDD
0
Acrylonitrile Benzo[k]fluoranthene Dieldrin
Benzene Bis(2-chloroethyl) ether Alpha-endosulfan
Bromoform Bis(2-ethylhexyl) phthalate Beta-endosulfan
Carbon tetrachloride Chrysene Endosulfan sulfate
Chlorobenzene Dibenzo[a,h]anthracene Endrin
Chlorodibromomethane 1,2-Dichlorobenzene Endrin aldehyde
Chloroform 1,3-Dichlorobenzene Heptachlor
Dichlorobromomethane 1,4-Dichlorobenzene Heptachlor epoxide
1,2-Dichloroethane 3,3 -Dichlorobenzidine PCB-1242
0
1,1-Dichloroethylene Diethyl phthalate PCB-1254
1,3-Dichloropropylene Dimethyl phthalate PCB-1221
Ethylbenzene Di-N-butyl phthalate PCB-1232
Methyl bromide 2,4-Dinitrotoluene PCB-1248
Methyl chloride 1,2-Diphenylhydrazine PCB-1260
Methylene chloride Fluoranthene PCB-1016
1,1,2,2-Tetrachloroethane Fluorene Toxaphene
Tetrachloroethylene Hexachlorobenzene

Table 2.3 lists the contaminants regulated under and (5) analysis methods that provide measurement capabil-
Section 307. Of equal importance, the list gives a sense of ities to nanograms per liter. Thus, the state of knowledge,
the variety of metals and organic compounds considered toxic although not complete, has come a long way from the incep-
above certain threshold concentration limits and that are sub- tion of the modern era of water treatment, i.e., since about
ject to treatment. In other words, the idea of a pollutant had 1880 (Box 2.3).
been expanded well beyond the traditional notions, prevalent
till about 1960, that BOD and SS were the main concerns.
2.3.1 KNOWLEDGE OF CONTAMINANTS
2.3 MATURATION OF WATER QUALITY The first formal compilation of substances that comprise water
quality was the 1952 book Water Quality Criteria by Profes-
KNOWLEDGE
sor Jack McKee of Cal Tech (and Partner, Camp, Dresser, and
From the beginning, before about 1900, knowledge of water McKee), commissioned by the State of California. The book
contaminants evolved based upon developments that included was revised and expanded by Harold Wolfe in 1962. It was an
(1) the mother sciences—chemistry and microbiology, (2) exhaustive treatise on substances that may be found in water
public mandates related to water quality standards, (3) specific and the effects of different concentrations. A similar book
knowledge about water contaminants and their ecological and called the EPA Yellow Book was published in 1973
health effects, (4) criteria for various kinds of uses of water, (USEPA, 1973), which had a wider distribution.