Dr. SIJAL FADHIL FARHOOD- M.Sc.(community medicine)-M.B.Ch.B.
GROUND WATER POLLUTION
Interactions between ground water and surface water are complex. Consequently, groundwater pollution, sometimes referred to as groundwater contamination, is not as easily classified as surface water pollution. By its very nature, groundwater aquifer are susceptible to contamination from sources that may not directly affect surface water bodies, and the distinction of point vs. non-point source may be irrelevant.
A spill or ongoing releases of chemical or radionuclidecontaminants into soil (located away from a surface water body) may not create point source or non-point source pollution, but can contaminate the aquifer below, defined as a toxin plume.
CAUSES OF WATER POLLUTION
The specific contaminants leading to pollution in water include a wide spectrum ofchemicals, pathogen and physical or sensory changes such as elevated temperature and discoloration. While many of the chemicals and substances that are regulated may be naturally occurring (Ca,Fe,Mn,Na,, etc.) the concentration is often the key in determining what is a natural component of water, and what is a contaminant. High concentrations of naturally-occurring substances can have negative impacts on aquatic flora and fauna.
CHEMICALS
Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that affects the primary productivity of the ecosystem. Depending on the degree of eutrophication, subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions in water quality may occur, affecting fish and other animal populations.
PATHOGENS
Coliform bacteria are a commonly used bacterial indicator of water pollution.
Other microorganism sometimes found in surface waters which have caused human health problems include:
PATHOGENS
Burkholderia pseudomallei
Cryptosporidium parvum
Giardia lamblia
Salmonella
Novovirus
High levels of pathogens may result from inadequately treated sewage discharges. This can be caused by a sewage plant designed with less than secondary treatment (more typical in less-developed countries). In developed countries, older cities with aginginfrastructure may have leaky sewage collection systems (pipes, pumps, valves), which can causesanitary sewer overflow. Some cities also have combind sewers, which may discharge untreated sewage during rain storms.
Pathogen discharges may also be caused by poorly managed livestock operations.
MACROSCOPIC POLLUTANTS
trash or garbage (e.g. paper, plastic, or food waste) discarded by people on the ground, along with accidental or intentional dumping of rubbish, that are washed by rainfall into storm drains and eventually discharged Macroscopic pollution—large visible items polluting the water—may be termed "floatables" in an urban stormwater context, or marin debris when found on the open seas, and can into surface waters
THERMAl POLLUTION
Thermal pollution is the rise or fall in the temperature of a natural body of water caused by human influence. Thermal pollution, unlike chemical pollution, results in a change in the physical properties of water. A common cause of thermal pollution is the use of water as a coolant by power plant and industrial manufacturers.
MARINE POLLUTION
Most water pollutants are eventually carried by rivers into the oceans. In some areas of the world the influence can be traced hundred of miles from the mouth of rivers.
DRINKING WATER
Drinking water or potable water is water of sufficiently high quality that can be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually consumed or used in food preparation.
Water quality and contaminants
The most common contamination of raw water sources is from human sewage and in particular human faecal pathogens and parasites. In 2006, waterborne diseases were estimated to cause 1.8 million deaths each year while about 1.1 billion people lacked proper drinking water. It is clear that people in the developing world need to have access to good quality water in sufficient quantity, water purification technology and availability and distribution systems for water.
DRINKING WATER REQUIREMENTS
Most water requires some type of treatment before use, even water from deep wells or springs. The extent of treatment depends on the source of the water. Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs.
Over the past decade, an increasing number of field-based studies have been undertaken to determine the success of POU measures in reducing waterborne disease. The ability of POU options to reduce disease is a function of both their ability to remove microbial pathogens if properly applied and such social factors as ease of use and cultural appropriateness.
INDICATORS OF SAFE DRINKING WATER
Access to safe drinking water is indicated by the number of people using proper sanitary sources. These improved drinking water sources include household connection, protected dug well, protected spring, and rain water collection.
Sources that don t encourage improved drinking water to the same extent as previously mentioned include: unprotected well, unprotected spring, rivers or ponds, vender-provided water, bottled water (consequential of limitations in quantity, not quality of water), and tanker truck water. Access to sanitary water comes hand in hand with access to improved sanitation facilities for excreta.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .