The Priority Pollutants are a set of chemical pollutants EPA regulates, and for which EPA has published analytical test methods. the Priority Pollutant list published at 40 CFR 423, Appendix A,An estimated 25% of death and disease globally, is linked to environmental hazards. The WHO, EPA have listed the persistent pollutants, which are included in this article along with the major and few minor health hazards of the vivid categories of pollutants. [1,2]
The UK environmental protection act (EPA) 1990, ‘pollution of the environment’ means pollution of the environment due to the release (into any environmental medium) from any process of substance which are capable of causing harm to man or any other living organism supported by the environment. The escape of any substance capable of causing harm to man or any other living organism supported by the environment. 
The priority pollutants can be classified on the basis of:-
- chemical and physical nature
- source of the pollutant
- environmental pathway used
- target organism affected
- gross effect on the Earth 
The Environmental Pollution Agency have short listed the priority pollutants.
In addition to this comprehensive list
- Asbestos, Barium, HCB, Cadmium, Tin and Petroleum Hydrocarbons are also included under the broad title of ‘PRIORITY POLLUTANTS’. 
Priority pollutants can be divided into 3 categories:-
- Volatile and non volatile organics 
DETECTION OF PRIORITY POLLUTANT (METALS)
- Atomic Absorption spectroscopy, a very sensitive method used to analyse the priority pollutants by the United States Environmental Protection Agency (EPA).
- Due to a few limitations in this methods the ability of dibenzyldithiocarbamate (DBDC) to form complexes with the priority is used, this is then followed by liquid chromatography, on a C18 column and using 64% methanol, 12%acetonitrile,5%tetrahydrofuran and19% Ph 5 acatate buffer as the mobile phase, which is quantified using ultraviolet and visible spectrophotometry. (10 out of the 13 priority pollutants are detected using this method.) 
Health hazards of heavy metals
The major and general health hazard due to metals is their direct influence as a carcinogen.[7,8]
Health hazards due to Arsenic
- The primary concerns are carcinogenicity and mutagenicity.
- Chronic exposure can result in poisoning of the nervous system, liver damage, and peripheral vascular disease, leading to gangrene of the lower limbs. This condition is commonly known as `black foot disease’.
- Chronic exposure to As is also associated with leukaemia, kidney and bladder cancers, dermatitis, hyper pigmentation, and arsenical keratosis.
- Arsenic acts as a non-genotoxic carcinogen. However, it affects DNA methylation and repair.
- Vomiting, diarrhea
- Peripheral nervous system problems
- Decreased intelligence
- Beathing problems [7,8,9]
The organs affected the most are:-
- Kidney : impaired renal functions, Increased excretion of low-molecular weight proteins in the urine.
- Increased risk of Lung cancer.
- Bone disorders: Osteomalacia, Osteoporosis and spontaneous bone fracture.
- Irritation Of The Lungs And Gastrointestinal Tract
- Cancer Of The Prostrate [8,9]
- Impaired Neurological Development (memory and learning difficulties, behavioural problems, reduced IQ)
- High blood pressure
- Kidney Failure
- Decreased sperm count
- Supression Of Haematological System 
- Gastro-Intestinal Disorders (digestive problems)
- Respiratory Tract Irritation
- Renal Failure
- Blindness and deafness
- Lack of co-ordination
- Mental retardation
Pesticides enter the food chain through water. This includes the derivatives of chlorinated hydrocarbons, herbicides and insecticides used on the soil. The mentioned categories of pesticides are very resistant and persistent in the environment, and have become ubiquitous over the years. The regularly used pesticides are mentioned.[5,13]
- DDT(Dichloro Diphenyl Trichloroethane)
- ChlordaneHCBor hexachlorobenzene
- Methoxychlor 
HEALTH HAZARDS DUE TO PERSISTANT PESTIDICES AND INSECTICIDES
Pesticides are designed to kill and because their mode of action is not specific to one species, they often kill or harm organisms other than pests, including humans. The health effects of pesticides depend on the type of pesticide. Following are the health hazards caused due to Organophosphates, DDT, Lindane, Carbamate and Pyrethroids. 
The major health hazards of pesticides are:-
- Neurological Health Effects
- Hormone Disruption
- Impaired Reproductive Developments
- Decreased Sperm Count And Motility 
NEUROLOGICAL HEALTH EFFECTS
- Memory Loss
- Loss Of Coordination
- Reduced Speed Of Response To Stimuli
- Reduced Visual Ability
- Altered Or Uncontrollable Mood
- Reduced Motor Skills.
- Convulsions And Seizures [10,11]
OTHER POSSIBLE HEALTH EFFECTS
- Allergies ( skin allergies that are toxic)
- Hypersensitivity to light, sound and touch
- Fatigue [10,11]
Acuteorganophosphateandcarbamateexposure causes signs and symptoms of excess acetylcholine, such as increased salivation and perspiration, narrowing of the pupils, nausea, diarrhea, decrease in blood pressure, muscle weakness, and fatigue. Some organophosphates also have a delayed neurological reaction characterized by muscle weakness in the legs and arms. 
SEMI VOLATILE AND VOLATILE ORGANICS
This group of Pollutants is wide ranging and consists of :-
- Chlorinated Alkanes (Carbon Tetrachloride)
- Chlorinated Ethenes (Polyvinyl Chloride Or Pvc)
- Polynuclear Aromatic Hydrocarbons (Naphtalene, Coal Tar),
- Pesticides, Herbicides And Fumigants (Ddt, Endrin, Aldrin, Lindane, Methoxychlor, Toxaphene And Silvex),
- Mono-Dichlorobenzenes (Solvents),
- Benzenes (Benzene, Toluene)
- Phenols And Chlorophenols And Trihalomethanes (Chloroform, Bromoform). 
HEALTH EFFECTS DUE TO ORGANICS
- Vinyl chloride is associated with cancer.
- PAH, induces cancer lung being the main target, 
- Phenols and chlorophenols lead to alterations in hepatic enzyme activities, gross increased liver weight and histopathological (hypertrophy, vacuolization, hyperplasia, fibrosis, necrosis and degeneration) effects is found following acute, intermediate and chronic oral exposure to PCP, Hepatocyte degeneration and centrilobular hypertrophy, Significant alterations in thyroid hormone levels have been observed, decrease fertility, and growth, signs of chloracne and minor disturbance of lipid metabolism., neurodevelopmental effects in infants. [3,whatever is the rest of the part] 
- Trihalomethanes can lead to colon cancer. 
Knowing about pollutants and their health hazards is not the end of it. Research has to be done on ways to curb this disaster and irreversible damage that has lured on our environment. Effort has to be made to find ways to tackle this pollution and PRIORITIZE Our Mother Nature and Human Health rather than POLLUTANTS!
- The health and environment linkages initiative, world health organization, UNEP, http://www.who.int, accessed on 02-05-2015.
- EPA, http://www.water.epa.gov, accessed on 3-05-2015.
- Gareth Evans and Judith Furlong (2003), Environmental Biotechnology Theory And Applications, John Wiley And Sons Ltd.
- USEPA Priority Pollutants, http://www.accutest.com, accessed on 3-05-2015.
- Fishery harbor manual on the prevention of pollution, http://www.fao.org, accessed on 3-05-2015.
- James H. Shofsthal and James K. Hardy, Method For The Determination Of The Priority Pollutant Metals By HPLC, Journal of Chromatographic Science, Vol 28, Issue 5, Pg 225-229.
- WHO, Europe, Health Risks Of Heavy Metals From Long Range Transboundary Air Pollution, World Health Organization, 2007, http://www.euro.who.int, accessed on 13-05-2015.
- Heavy metals; Mercury, Arsenic, Lead, A Century’s Old story http://pollutioninpeople.org/toxics/metals
- Lars Järup, Hazards of heavy metal contamination, J Epidemiol Community Health2002;56:824-825
- UNEP (Urban Environmental Unit United Nations Environmental Programme), Environmental pollution and impacts on public health.
- Health Risks Of Persistent Organic Pollutants From Long-Range Transboundary Air Pollution, WHO Europe,
- Peter Orris, Lin Kraatz, Karen Perry and Joe Asbury, Persistent Organic Pollutants and Human Health,May 2000, published by World Federation Of Public Health Associations.
- Effect of pesticide on human health www.toxipedia.org,15/05/2015
- Pereira and Michael A., Health Risk of the Trihalomethanes Found in Drinking Water Carcinogenic Activity and Interactions, Medical College of Ohio,2000.