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مهندسی بهداشت محیط زیست
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آلودگي دي اكسين ها از مزرعه تا سفره

 

 

دي اكسين ها  چيستند ؟

دي اكسين ها يا Repeat Offenders از آلاينده هاي شيميايي خطرناك هستند و به گروه  Dirty DoSen Club تعلق دارند كه به عنوان آلايندهاي ارگانيكي پايدار ( POPs ) شناخته مي شوند چنانچه دي اكسين ها وارد محيط زيست يا بدن انسان شوند ، به دليل قابليت حلاليت عجيب خود در چربي ها همانجا مي مانند . معدل نيمه عمر آن ها به هفت سال مي رسد وجود  دي اكسين ها در محيط زيست سبب ورود آن ها به زنجيره غذايي مي شود .

 

منابع آلودگي از طريق دي اكسين ها كدامند ؟

دي اكسين ها محصولات جانبي فر آيند هاي صنعتي هستند اما در طبيعت تحت شرايطي نظير فوران آتشفشان يا آتش سوزي هاي جنگل نيز بوجود مي آيد . اين تركيبات همچنين فر آورده هاي جانبي نا خواسته اي هستند که  از سوختن مواد ارگانيكي شامل كلرين chlorine  Containing تشكيل مي شوند . آن ها محصولات جانبي ناخواسته گروه وسيعي از  فر آيندهاي توليدي شامل تصفيه ، سفيد كردن خمير كاغذ و نيز توليد برخي علف كش ها و آفت كش ها هستند . دستگاه هاي سوزاندن زباله هاي جامد به دليل سوخت ناقص خود بيشترين سهم را در آزاد شدن دي اكسين ها و ورود آن ها به محيط زيست دارند . دي اكسين ها در سراسر دنيا در تمام عناصر ( media )  از جمل هوا ، خااك . آب مواد رسوبي ، مواد غذايي به ويژه محصولات لبني . گوشت . ماهي و صدف يافت مي شوند . بيشترين مقدار اين تركيبات در خاك . رسوبات و بدن حيوانات و كمترين آن ها در آب و هوا وجود دارد .

پسمانده روغن هاي صنعتي حاوي مقدار زيادي از دي اكسين ها هستند . ذخيره طولاني مدت اين مواد ممكن است سبب آزاد شدن آنها در محيط زيست وفر آيند توليد غذايي حيوانات و انسان شود .

 

آيا آلودگي با دي اكسين اتفاق افتاده است ؟ 

 گزارش هايي از وجود مقادير زياد دي اكسين در گوشت مرغ  و تخم مرغ در بلژيك وجود دارد . تصور مي رود دليل آن ، نوع  تغذيه حيوانات باشد. 

نوع خاصي از دي اكسين ها به دليل اثرات سوءء  بر سلامتي انسان به شكل گسترده اي مورد مطالعه  قرار گرفته  است و وجود آن به عنوان يك آلاينده در دسته اي از علف كش ها مانند عامل نارنجي كه در سراسر جنگ ويتنام به كار رفت و تاثيرات منفي بسيار زياد آن  بر انسان  ثابت شد . همچنين زماني كه در سال 1976 حادثه تلخي در يك كارخانه شيميايي در ايتاليا اتفاق افتاد ،  مورد مطالعه قرار گرفت . در اين حادثه ابري از آلاينده هاي شيميايي شامل دي اكسين ها در هوا آزاد شد و در نتيجه منطقه اي به وسعت 15 كيلومتر مربع با جمعيتي حدود 37000 نفر آلوده شد .

 مورد ديگر از آلودگي غذايي با دي اكسين در بخش جنوبي ايالات متحده امريكا در سال 1997 اتفاق افتاد مرغ ، تخم مرغ و نوعي ماهي به دي اكسين آلوده شده بودند  . زيرا نوعي خاك رس كه در كارخانجات توليد غذايي حيوانات مورد استفاده  قرار مي گرفت به دي اكسين آلوده بود . بازرسين آامريكايي سر انجام خاك آلوده را در معدن خاك رس پيدا كردند ولي از آنجا كه دليلي  مبتني بر آن كه زباله ها ي خطرناك در معدن دفن شده باشند ، وجود نداشت فرض را بر اين گذاشتندكه آلودگي مربوط به دوران ما قبل تاريخ باشد .

قبل از آن هم گزارش هايي مبني بر آلودگي مواد غذايي از ديگر نقاط دنيا منتشر شده بود . گرچه همه  كشورها در معرض آلودگي قرار دارند . اما بيشترين آلودگي از كشور هاي صنعتي گزارش شده و دليل آن وجود امكانات كافي جهت پايش آلودگي هاي غذايي و آگاهي بيشتر نسبت به خطرات  و نيز كنترل منظم براي كشف دي اكسين ها وجود دارد .

 

تاثيرات دي اكسن ها بر سلامت انسان :

تماس كوتاه مدت  انسان با سطح گسترده اي از دي اكسين ها ممكن است به جراحت هاي پوستي نظير chlorance يا ايجاد  لكه هاي روي پوست و نيز تغيير عملكرد كبد منجر شود . تماس دراز مدت به سيتم ايمني بدن سيستم عصبي  غدد و عملكرد و ترميم بدن مربوط مي شود . تماس با اين الاينده تا كنون در حيوانات موجب بروز چندين نوع سرطان شده است . TCDO در سال 1997 توسط بنگاه بين المللي  تحقيقات سرطان( IARC )مورد بررسي قرار گرفت . بر اساس اطلاعات اپيدميولوژي اين بنگاه دي اكسسين ها در گروه “ عوامل  شناخت شده ايجاد سرطان در انسان قرار گرفته است .

 

آيا در تماس با دي اكسين ها گروه خاصي بيشتر در مخاطره قرار مي گيرند ؟

جنين ببيشترين حساسيت را در مقابل دي اكسين ها دارد . نوزادان نيز اسيب پذير ي بيشتر ي دارند . بعضي افراد و يا گروه ها به دليل رژيم  غذايي در معرض تماس با مقدار بيشتري از دي اكسين ها قرار دارند . گرو هايي نظير كارگران صنايع كاغذ ،كارخانه هاي مخصوص سوزاندن زباله و سايت هاي زباله هاي خطرناك نمونه هاي كوچكي از اين دست هستند .

نقل از سايت :

WWW.EARTHWATCHERS.ORG

+ نوشته شده در  دوشنبه بیست و چهارم اردیبهشت 1386ساعت 1:5 قبل از ظهر  توسط محمد سليماني   | 

Contaminant

MCL or TT1 (mg/L)2

Potential health effects from exposure above the MCL

Common sources of contaminant in drinking water

Public Health Goal

OC

Acrylamide

TT8

Nervous system or blood problems;

Added to water during sewage/wastewater increased risk of cancer treatment

zero

OC

Alachlor

0.002

Eye, liver, kidney or spleen problems; anemia; increased risk of cancer

Runoff from herbicide used on row crops

zero

R

Alpha particles

15 picocuries per Liter (pCi/L)

Increased risk of cancer

Erosion of natural deposits of certain minerals that are radioactive and may emit a form of radiation known as alpha radiation

zero

IOC

Antimony

0.006

Increase in blood cholesterol; decrease in blood sugar

Discharge from petroleum refineries; fire retardants; ceramics; electronics; solder

0.006

IOC

Arsenic

0.010 as of 1/23/06

Skin damage or problems with circulatory systems, and may have increased risk of getting cancer

Erosion of natural deposits; runoff from orchards, runoff from glass & electronics production wastes

0

IOC

Asbestos (fibers >10 micrometers)

7 million fibers per Liter (MFL)

Increased risk of developing benign intestinal polyps

Decay of asbestos cement in water mains; erosion of natural deposits

7 MFL

OC

Atrazine

0.003

Cardiovascular system or reproductive problems

Runoff from herbicide used on row crops

0.003

IOC

Barium

2

Increase in blood pressure

Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits

2

OC

Benzene

0.005

Anemia; decrease in blood platelets; increased risk of cancer

Discharge from factories; leaching from gas storage tanks and landfills

zero

OC

Benzo(a)pyrene (PAHs)

0.0002

Reproductive difficulties; increased risk of cancer

Leaching from linings of water storage tanks and distribution lines

zero

IOC

Beryllium

0.004

Intestinal lesions

Discharge from metal refineries and coal-burning factories; discharge from electrical, aerospace, and defense industries

0.004

R

Beta particles and photon emitters

4 millirems per year

Increased risk of cancer

Decay of natural and man-made deposits of certain minerals that are radioactive and may emit forms of radiation known as photons and beta radiation

zero

DBP

Bromate

0.010

Increased risk of cancer

Byproduct of drinking water disinfection

zero

IOC

Cadmium

0.005

Kidney damage

Corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries; runoff from waste batteries and paints

0.005

OC

Carbofuran

0.04

Problems with blood, nervous system, or reproductive system

Leaching of soil fumigant used on rice and alfalfa

0.04

OC

Carbon tetrachloride

0.005

Liver problems; increased risk of cancer

Discharge from chemical plants and other industrial activities

zero

D

Chloramines (as Cl2)

MRDL=4.01

Eye/nose irritation; stomach discomfort, anemia

Water additive used to control microbes

MRDLG=41

LEGEND D Dinsinfectant IOC Inorganic Chemical OC Organic Chemical DBP Disinfection Byproduct M Microorganism R Radionuclides 1Contaminant MCL or TT1 (mg/L)2 Potential health effects from exposure above the MCL Common sources of contaminant in drinking water Public Health Goal

OC

Chlordane

0.002

Liver or nervous system problems; increased risk of cancer

Residue of banned termiticide

zero

D

Chlorine (as Cl2)

MRDL=4.01

Eye/nose irritation; stomach discomfort

Water additive used to control microbes

MRDLG=41

D

Chlorine dioxide (as ClO2)

MRDL=0.81

Anemia; infants & young children: nervous system effects

Water additive used to control microbes

MRDLG=0.81

DBP

Chlorite

1.0

Anemia; infants & young children: nervous system effects

Byproduct of drinking water disinfection

0.8

OC

Chlorobenzene

0.1

Liver or kidney problems

Discharge from chemical and agricultural chemical factories

0.1

IOC

Chromium (total)

0.1

Allergic dermatitis

Discharge from steel and pulp mills; erosion of natural deposits

0.1

IOC

Copper

TT7; Action Level = 1.3

Short term exposure: Gastrointestinal distress. Long term exposure: Liver or kidney damage. People with Wilson’s Disease should consult their personal doctor if the amount of copper in their water exceeds the action level

Corrosion of household plumbing systems; erosion of natural deposits

1.3

M

Cryptosporidium

TT3

Gastrointestinal illness (e.g., diarrhea, vomiting, cramps)

Human and animal fecal waste

zero

IOC

Cyanide (as free cyanide)

0.2

Nerve damage or thyroid problems

Discharge from steel/metal factories; discharge from plastic and fertilizer factories

0.2

OC

2,4-D

0.07

Kidney, liver, or adrenal gland problems

Runoff from herbicide used on row crops

0.07

OC

Dalapon

0.2

Minor kidney changes

Runoff from herbicide used on rights of way

0.2

OC

1,2-Dibromo-3-chloropropane (DBCP)

0.0002

Reproductive difficulties; increased risk of cancer

Runoff/leaching from soil fumigant used on soybeans, cotton, pineapples, and orchards

zero

OC

o-Dichlorobenzene

0.6

Liver, kidney, or circulatory system problems

Discharge from industrial chemical factories

0.6

OC

p-Dichlorobenzene

0.075

Anemia; liver, kidney or spleen damage; changes in blood

Discharge from industrial chemical factories

0.075

OC

1,2-Dichloroethane

0.005

Increased risk of cancer

Discharge from industrial chemical factories

zero

OC

1,1-Dichloroethylene

0.007

Liver problems

Discharge from industrial chemical factories

0.007

OC

cis-1,2-Dichloroethylene

0.07

Liver problems

Discharge from industrial chemical factories

0.07

OC

trans-1,2-Dichloroethylene

0.1

Liver problems

Discharge from industrial chemical factories

0.1

OC

Dichloromethane

0.005

Liver problems; increased risk of cancer

Discharge from drug and chemical factories

zero

OC

1,2-Dichloropropane

0.005

Increased risk of cancer

Discharge from industrial chemical factories

zero

OC

Di(2-ethylhexyl) adipate

0.4

Weight loss, live problems, or possible reproductive difficulties

Discharge from chemical factories

0.4

OC

Di(2-ethylhexyl) phthalate

0.006

Reproductive difficulties; liver problems; increased risk of cancer

Discharge from rubber and chemical factories

zero

OC

Dinoseb

0.007

Reproductive difficulties

Runoff from herbicide used on soybeans and vegetables

0.007

OC

Dioxin (2,3,7,8-TCDD)

0.00000003

Reproductive difficulties; increased risk of cancer

Emissions from waste incineration and other combustion; discharge from chemical factories

zero

OC

Diquat

0.02

Cataracts

Runoff from herbicide use

0.02

OC

Endothall

0.1

Stomach and intestinal problems

Runoff from herbicide use

0.1

LEGEND D Dinsinfectant IOC Inorganic Chemical OC Organic Chemical DBP Disinfection Byproduct M Microorganism R Radionuclides 2Contaminant MCL or TT1 (mg/L)2 Potential health effects from exposure above the MCL Common sources of contaminant in drinking water Public Health Goal

OC

Endrin

0.002

Liver problems

Residue of banned insecticide

0.002

OC

Epichlorohydrin

TT8

Increased cancer risk, and over a long period of time, stomach problems

Discharge from industrial chemical factories; an impurity of some water treatment chemicals

zero

OC

Ethylbenzene

0.7

Liver or kidneys problems

Discharge from petroleum refineries

0.7

OC

Ethylene dibromide

0.00005

Problems with liver, stomach, reproductive system, or kidneys; increased risk of cancer

Discharge from petroleum refineries

zero

IOC

Fluoride

4.0

Bone disease (pain and tenderness of the bones); Children may get mottled teeth

Water additive which promotes strong teeth; erosion of natural deposits; discharge from fertilizer and aluminum factories

4.0

M

Giardia lamblia

TT3

Gastrointestinal illness (e.g., diarrhea, vomiting, cramps)

Human and animal fecal waste

zero

OC

Glyphosate

0.7

Kidney problems; reproductive difficulties

Runoff from herbicide use

0.7

DBP

Haloacetic acids (HAA5)

0.060

Increased risk of cancer

Byproduct of drinking water disinfection

n/a6

OC

Heptachlor

0.0004

Liver damage; increased risk of cancer

Residue of banned termiticide

zero

OC

Heptachlor epoxide

0.0002

Liver damage; increased risk of cancer

Breakdown of heptachlor

zero

M

Heterotrophic plate count (HPC)

TT3

HPC has no health effects; it is an analytic method used to measure the variety of bacteria that are common in water. The lower the concentration of bacteria in drinking water, the better maintained the water system is.

HPC measures a range of bacteria that are naturally present in the environment

n/a

OC

Hexachlorobenzene

0.001

Liver or kidney problems; reproductive difficulties; increased risk of cancer

Discharge from metal refineries and agricultural chemical factories

zero

OC

Hexachlorocyclopentadiene

0.05

Kidney or stomach problems

Discharge from chemical factories

0.05

IOC

Lead

TT7; Action Level = 0.015

Infants and children: Delays in physical or mental development; children could show slight deficits in attention span and learning abilities; Adults: Kidney problems; high blood pressure

Corrosion of household plumbing systems; erosion of natural deposits

zero

M

Legionella

TT3

Legionnaire’s Disease, a type of pneumonia

Found naturally in water; multiplies in heating systems

zero

OC

Lindane

0.0002

Liver or kidney problems

Runoff/leaching from insecticide used on cattle, lumber, gardens

0.0002

IOC

Mercury (inorganic)

0.002

Kidney damage

Erosion of natural deposits; discharge from refineries and factories; runoff from landfills and croplands

0.002

OC

Methoxychlor

0.04

Reproductive difficulties

Runoff/leaching from insecticide used on fruits, vegetables, alfalfa, livestock

0.04

IOC

Nitrate (measured as Nitrogen)

10

Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome.

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits

10

IOC

Nitrite (measured as Nitrogen)

1

Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome.

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits

1

LEGEND D Dinsinfectant IOC Inorganic Chemical OC Organic Chemical DBP Disinfection Byproduct M Microorganism R Radionuclides 3Contaminant MCL or TT1 (mg/L)2 Potential health effects from exposure above the MCL Common sources of contaminant in drinking water Public Health Goal

OC

Oxamyl (Vydate)

0.2

Slight nervous system effects

Runoff/leaching from insecticide used on apples, potatoes, and tomatoes

0.2

OC

Pentachlorophenol

0.001

Liver or kidney problems; increased cancer risk

Discharge from wood preserving factories

zero

OC

Picloram

0.5

Liver problems

Herbicide runoff

0.5

OC

Polychlorinated biphenyls (PCBs)

0.0005

Skin changes; thymus gland problems; immune deficiencies; reproductive or nervous system difficulties; increased risk of cancer

Runoff from landfills; discharge of waste chemicals

zero

R

Radium 226 and Radium 228 (combined)

5 pCi/L

Increased risk of cancer

Erosion of natural deposits

zero

IOC

Selenium

0.05

Hair or fingernail loss; numbness in fingers or toes; circulatory problems

Discharge from petroleum refineries; erosion of natural deposits; discharge from mines

0.05

OC

Simazine

0.004

Problems with blood

Herbicide runoff

0.004

OC

Styrene

0.1

Liver, kidney, or circulatory system problems

Discharge from rubber and plastic factories; leaching from landfills

0.1

OC

Tetrachloroethylene

0.005

Liver problems; increased risk of cancer

Discharge from factories and dry cleaners

zero

IOC

Thallium

0.002

Hair loss; changes in blood; kidney, intestine, or liver problems

Leaching from ore-processing sites; discharge from electronics, glass, and drug factories

0.0005

OC

Toluene

1

Nervous system, kidney, or liver problems

Discharge from petroleum factories

1

M

Total Coliforms (including fecal coliform and E. coli)

5.0%4

Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5

Coliforms are naturally present in the environment as well as feces; fecal coliforms and E. coli only come from human and animal fecal waste.

zero

DBP

Total Trihalomethanes (TTHMs)

0.10

0.080 after 12/31/03

Liver, kidney or central nervous system problems; increased risk of cancer

Byproduct of drinking water disinfection

n/a6

OC

Toxaphene

0.003

Kidney, liver, or thyroid problems; increased risk of cancer

Runoff/leaching from insecticide used on cotton and cattle

zero

OC

2,4,5-TP (Silvex)

0.05

Liver problems

Residue of banned herbicide

0.05

OC

1,2,4-Trichlorobenzene

0.07

Changes in adrenal glands

Discharge from textile finishing factories

0.07

OC

1,1,1-Trichloroethane

0.2

Liver, nervous system, or circulatory problems

Discharge from metal degreasing sites and other factories

0.20

OC

1,1,2-Trichloroethane

0.005

Liver, kidney, or immune system problems

Discharge from industrial chemical factories

0.003

OC

Trichloroethylene

0.005

Liver problems; increased risk of cancer

Discharge from metal degreasing sites and other factories

zero

M

Turbidity

TT3

Turbidity is a measure of the cloudiness of water. It is used to indicate water quality and filtration effectiveness (e.g., whether disease-causing organisms are present). Higher turbidity levels are often associated with higher levels of disease-causing micro-organisms such as viruses, parasites and some bacteria. These organisms can cause symptoms such as nausea, cramps, diarrhea, and associated headaches.

Soil runoff

n/a

R

Uranium

30 ug/L as of 12/08/03

Increased risk of cancer, kidney toxicity

Erosion of natural deposits

zero

LEGEND D Dinsinfectant IOC Inorganic Chemical OC Organic Chemical DBP Disinfection Byproduct M Microorganism R Radionuclides 4Contaminant MCL or TT1 (mg/L)2 Potential health effects from exposure above the MCL Common sources of contaminant in drinking water Public Health Goal

OC

Vinyl chloride

0.002

Increased risk of cancer

Leaching from PVC pipes; discharge from plastic factories

zero

M

Viruses (enteric)

TT3

Gastrointestinal illness (e.g., diarrhea, vomiting, cramps)

Human and animal fecal waste

zero

OC

Xylenes (total)

10

Nervous system damage

Discharge from petroleum factories; discharge from chemical factories

10

NOTES

1 Definitions

• Maximum Contaminant Level Goal (MCLG)—The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals.

• Maximum Contaminant Level (MCL)—The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.

• Maximum Residual Disinfectant Level Goal (MRDLG)—The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.

• Maximum Residual Disinfectant Level (MRDL)—The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

• Treatment Technique (TT)—A required process intended to reduce the level of a contaminant in drinking water.

2 Units are in milligrams per liter (mg/L) unless otherwise noted. Milligrams per liter are equivalent to parts per million (ppm).

3 EPA’s surface water treatment rules require systems using surface water or ground water under the direct influence of surface water to (1) disinfect their water, and (2) filter their water or meet criteria for avoiding filtration so that the following contaminants are controlled at the following levels:

Cryptosporidium (as of 1/1/02 for systems serving >10,000 and 1/14/05 for systems serving <10,000) 99% removal.

Giardia lamblia: 99.9% removal/inactivation

• Viruses: 99.99% removal/inactivation

Legionella: No limit, but EPA believes that if Giardia and viruses are removed/inactivated, Legionella will also be controlled.

• Turbidity: At no time can turbidity (cloudiness of water) go above 5 nephelolometric turbidity units (NTU); systems that filter must ensure that the turbidity go no higher than 1 NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily samples in any month. As of January 1, 2002, for systems servicing >10,000, and January 14, 2005, for systems servicing <10,000, turbidity may never exceed 1 NTU, and must not exceed 0.3 NTU in 95% of daily samples in any month.

• HPC: No more than 500 bacterial colonies per milliliter

• Long Term 1 Enhanced Surface Water Treatment (Effective Date: January 14, 2005); Surface water systems or (GWUDI) systems serving fewer than 10,000 people must comply with the applicable Long Term 1 Enhanced Surface Water Treatment Rule provisions (e.g. turbidity standards, individual filter monitoring, Cryptosporidium removal requirements, updated watershed control requirements for unfiltered systems).

• Filter Backwash Recycling: The Filter Backwash Recycling Rule requires systems that recycle to return specific recycle flows through all processes of the system’s existing conventional or direct filtration system or at an alternate location approved by the state.

4 No more than 5.0% samples total coliform-positive in a month. (For water systems that collect fewer than 40 routine samples per month, no more than one sample can be total coliform-positive per month.) Every sample that has total coliform must be analyzed for either fecal coliforms or E. coli if two consecutive TC-positive samples, and one is also positive for E. coli fecal coliforms, system has an acute MCL violation.

5 Fecal coliform and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Disease-causing microbes (pathogens) in these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. These pathogens may pose a special health risk for infants, young children, and people with severely compromised immune systems.

6 Although there is no collective MCLG for this contaminant group, there are individual MCLGs for some of the individual contaminants:

• Haloacetic acids: dichloroacetic acid (zero); trichloroacetic acid (0.3 mg/L)

• Trihalomethanes: bromodichloromethane (zero); bromoform (zero); dibromochloromethane (0.06 mg/L)

7 Lead and copper are regulated by a Treatment Technique that requires systems to control the corrosiveness of their water. If more than 10% of tap water samples exceed the action level, water systems must take additional steps. For copper, the action level is 1.3 mg/L, and for lead is 0.015 mg/L.

8 Each water system must certify, in writing, to the state (using third-party or manufacturers certification) that when it uses acrylamide and/or epichlorohydrin to treat water, the combination (or product) of dose and monomer level does not exceed the levels specified, as follows: Acrylamide = 0.05% dosed at 1 mg/L (or equivalent); Epichlorohydrin = 0.01% dosed at 20 mg/L (or equivalent).

LEGEND D Dinsinfectant IOC Inorganic Chemical OC Organic Chemical DBP Disinfection Byproduct M Microorganism R Radionuclides 5

National Secondary Drinking Water Standards

National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. EPA recommends secondary standards to water systems but does not require systems to comply. However, states may choose to adopt them as enforceable standards.

Contaminant

Secondary Standard

Aluminum

0.05 to 0.2 mg/L

Chloride

250 mg/L

Color

15 (color units)

Copper

1.0 mg/L

Corrosivity

noncorrosive

Fluoride

2.0 mg/L

Foaming Agents

0.5 mg/L

Iron

0.3 mg/L

Manganese

0.05 mg/L

Odor

3 threshold odor number

pH

6.5-8.5

Silver

0.10 mg/L

Sulfate

250 mg/L

Total Dissolved Solids

500 mg/L

Zinc

5 mg/L

Office of Water (4606M)

EPA 816-F-03-016

www.epa.gov/safewater

June 2003

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