emerging and re emerging challenges in water quality- presentation

EMERGING AND RE-EMERGING CHALLENGES IN WATER QUALITY

GAQAVU SISIPHOADELABU OLUSESANSEPTEMBER DOLLY

OUT-LINE

• Water quality• Physiochemical parameters that influence water

quality• Water quality indicators• Emerging and Re-emerging challenges in water

quality• Potential drivers of emerging and re-emerging

pathogens in water• Recommendations

Introduction• Water quality- the chemical, physical and biological

characteristics of water that measure the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose

• Emerging challenges-are those challenges that have appeared for the first time, or have occurred previously but are increasing in incidence or expanding into areas where they have not previously been reported

• Re-emerging challenges- are those challenges that emerge again; come into sight once more.

Physiochemical Parameters

Water quality Indicators

• Turbidity• pH• dissolved oxygen• temperature• nitrates• bio-indicators

Bio-indicators

• Faecal Coliforms are naturally occurring bacteria found in the intestines of all warm blooded animals (including humans) and birds. The presence of Faecal Coliforms is an indicator of contamination by sewage waste.

• They are not pathogenic (disease causing) but indicate that pathogenic bacterial and viruses may be present

Bio-Indicators• Escherichia coli(E. coli) is the major species in

the faecal coliform group• It is considered the best indicator of faecal

pollution and the possible presence of pathogens such as (E.coli 0157:H7, Shigella), and viruses (Rotavirus, Hepatitis E virus), Protozoa (Giardia, Cryptosporidium)

• Cyanobacteria/ blue-green algae float on the surface and are associated with water quality problems

Pathogens

E.coli 0157H:7 Shigella

Cryptosporangium Giardia Rotavirus

Emerging and Re-emerging challenges• Polluted water run-off

Faecal material as well as other pollutants can be transported to waterways through runoff. How quickly they are transported partially depend on the type of land use

Lands that support domesticated animals, such as cattle, dogs, or horses, can also be a source of bacteria, particularly if animals enter the water for drinking or if heavy rain washes manure from the land into receiving waters.

Challenges• Combined sewer overflow

Some sewer and storm water pipes are not separated, when a large storm event occurs, the waste water treatment plants cannot handle the excess volume of water being pumped to them. As a result, untreated sewage along with storm water is dumped directly into rivers and streams

Combined sewer over flow

• Rapid Urbanization Is caused by rapid population growth which brings about poor

sanitation, also increases the number of urban dwellers practising open defecation, e.g. in most low-middle income countries, open defecation increased from 140 million in 1990 to 169 million in 2008 (Chiramba,2010)

In most developing countries wastewater is discharged directly into the sea or rivers without treatment.

Many large cities do not have treatment plants or plants quickly become undersized as urban population growth outpaces investments.

Discharge of untreated wastewater shifts problems to downstream areas

• Pipeline contamination

Despite the treatment of water sources and use of chlorine as a disinfectant, contamination of piped water supply continues to occur, without necessarily causing large easy to recognise out-breaks, through leaks or other vulnerable parts of the pipe system, and during maintenance work

Bacteria, fungi, and protozoa can attach to the inner surfaces of the pipes and some may grow to produce biofilms which have been seen to contain one or more species of pathogens

Pipeline contamination

Waterborne pathogens

• Pathogens are disease causing microorganisms that can create health risks.

• They can be introduced into estuaries from inadequately treated sewage, runoff from urban areas, combined sewer overflows and waste from pets and wildlife

• They pose a health threat to human activities.

Waterborne pathogens• Emerging pathogens- are those that have appeared

in a human population for the first time, or have occurred previously but are increasing in incidence or expanding into areas where they have not previously been reported

• Re-emerging pathogens are those whose incidence is increasing as a result of long-term changes in their underlying epidemiology

New environment

New environment

• Adaptations by one partner to exploit new environments will often stimulate the other to modify its characteristics to take advantage of the change.

• As a consequence of this cycle of interaction created by changing environments, new strains of pathogen will evolve.

• Over time, these strains may emerge as new species with characteristic disease symptoms.

New technology

• Many of these technologies will have significant benefits, but unforeseen problems with a few may introduce new risks, such as harmful by-products or pathways of transmission that may lead to the re-emergence of water-related pathogens.

• In the context of new technologies, water distribution systems show how an engineering solution to one problem can create new opportunities for contact between humans and water-related pathogens.

New technology

• Zoonotic pathogens (Cryptosporidium, E.coli O157 and Campylobacter) are an example of emerging and re-emerging pathogens that result/emerge due to intensive livestock farming which frequently result in the discharge of pathogens into water from concentrated animal wastes and animal feeding operations.

• This shows how a substantial improvement of a long-term practice can impact watercourses in ways that are not anticipated

Recommendations• Good sanitation practises - community awareness, educating people on the re-emergence of

these challenges • Integrated and sustainable water management system• Improved engineered system by creating separate pipes for

sewage and storm water• Avoid cross contamination during repair or maintenance

work of pipelines• Increase in periodic treatment of water so as to combat the

re-emegence of pathogens• Well managed waste water treatment plants• General guidelines on irrigation water quality should be

applied to avoid immediate, short and long term detrimental effects on the environment

Recommendations• Monitoring of ground and surface water

resources close to the wastewater area should be carried out regularly to provide early warning of pollution status and risk

• Promote the use of wastewater in agriculture as an alternative to discharge surface waters will decrease the potential for eutrophication of surface waters

• Promotion of treatment procedures for waste purification which are cost effective and environmentally friendly

emerging and re emerging challenges in water quality- presentation

Science