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Water Quality
Water Quality
Air pollution in Sri Lanka’s urban areas has decreased by up to 75% during the lockdown imposed in response to the COVID-19 pandemic, while plastic pollution and other forms of marine pollution have decreased by up to 40% along the island’s coastline, authorities say.
Experts say meteorological conditions are also a factor, including the monsoonal change in wind direction and lack of rainfall in recent months.
But the environmental respite is likely to be temporary, while the lockdown period threatens to see a surge in another type of waste — face masks — washing out to sea and on beaches if no proper waste management mechanisms are introduced.
Experts say the tangible improvements in environmental indicators give a glimpse of how effective lifestyle and economic changes can lead to lasting pollution reduction in Sri Lanka.
COLOMBO
COLOMBO
The COVID-19 pandemic has sent half the global population into some form of lockdown. Factories have closed, streets and highways lie empty, restaurants no longer serve customers. Sri Lanka, like most other countries, has imposed strict measures to contain the spread of the virus. And like in many other countries, the sweeping halt in activity has had a tangible impact on pollution.
LESS MARINE POLLUTION
LESS MARINE POLLUTION
Sri Lanka’s lockdown has also seen a decline in marine pollution, according to the general manager of the Marine Environment Protection Authority (MEPA).
We have observed that plastic pollution on the beaches has gone down by 40% while nitrate and phosphate levels have decreased by 30%.
Around 80% of marine pollution originates on land, and different types of plastic comprise most of it. Huge garbage patches float on the waves, toxic microplastics are eaten by fish and work their way up the food chain, and chemical pollutants create dead zones with low oxygen and cause algal blooms that can kill fish and contaminate ecosystems.
Experts say that more data is needed to draw definite conclusions about the extent to which the lockdown on its own has contributed to the decline in marine pollution. MEPA has a monitoring system in place to collect monthly data on water quality and pollution, but because of the lockdown, only a limited number of stations have been operating, with data coming in from only five districts.
As with air pollution, there are also meteorological factors at work. The COVID lockdown might be one reason for the reduced pollution, but it is also because there has been no rain until July of 2020 which accelerates the washing of land-based waste and pollutants out to sea.
But recently, Plastic Pellet Spill from Burning Ship caused 'Worst Beach Pollution' in Sri Lanka's history. A chemical-laden ship sank off the coast of Sri Lanka after burning for nearly two weeks. ... It was carrying 1,486 containers, including 25 metric tons (approximately 28 U.S. tons) of nitric acid and other chemicals. with the explosion of the ship with tons of chemicals in the Sri Lankan sea near Colombo Harbor the sea water has been polluted vastly. This pollution has been directly affected on marine lives. The turtles, dolphins, corals are dying. So, this has been affected on the fishermen around the country. Although this is not an impact of Covid-19 the poor fishing community is going to suffer with this vast sea pollution. Also this affects on the tourism too. So, this is not only an environmental issue but also an economical issue.
Water Quality of River Basins in Sri Lanka
Water Quality of River Basins in Sri Lanka
Water quality in Kelani River
Water quality in Kelani River
Kelani River, having the total length of 145 km and 2292 sq. km of river basin is the second largest watershed and it is the most polluted river in Sri Lanka due to rapid growth of industries located in close vicinity of the river and passes through the country through most populated capital city.
The main sources of water pollution in Kelani river is the land based sources such as treated and untreated industrial effluents, agricultural runoff, domestic and municipal effluents. The gravity of water pollution is apparent when examining water quality measurements of Kelani River, which meets a major part of the demand for pipe borne drinking water supplies of Colombo. Kelani River is an important source of drinking water for the Colombo District and there is a water supply intake point at Ambatale, 14 kilometers from the river mouth. However, sewage from low-income settlements and industrial effluents (especially from tanning and metal finishing and processing industries) from a large number of industries are discharged conveniently to the Kelani River.
Furthermore, the lower reach of the river has been subject to saline water intrusion from the ocean making the water non-potable due to excessive sand mining and lowering of river beds at the lower reaches in the Kelani River, where sand mining is particularly severe with the salt wedge has extended inwards to Ambatale (about 14 km from its point of discharge) on several occasions. This is a serious concern as much of the potable water supply for Colombo is extracted from the Kelani River at Ambatale.
The discharge of wastewater into the environment from industrial activities is regulated by the Environmental Protection Licenses (EPL) schemes implemented under the provisions of the section 23 (a) of the National Environmental Act of 1980. As specified in the Act it is mandatory to obtain an EPL to discharge wastewater into the environment from an industry. Industries which discharge wastewater into the environment are required to treat their wastewaters up to the relevant standards to be qualified basically to obtain an EPL. The licenses so issued will specify the standard and criteria to be met by the respective industry discharging its effluent into the environment.
Even though the industries are covered with environmental protection licensing schemes, there is no regular monitoring mechanism to evaluate their meeting of discharge criteria and to control the pollutant loads discharged into the Kelani river.
pollution status of the Kelani river and some of its tributaries were investigated from 2003 with respect to pH, Electrical conductivity, Turbidity, DO, BOD, COD, Chloride, nutrients and microbiological parameters. Also, some dissolved form of heavy metals such as Pb and Cr were analyzed. Principal component analysis revealed that the river water was negatively impacted by pollutants from anthropogenic sources as well as natural sources. Seawater intrusion faecal contamination and erosion of the soil into the river water are natural activities stressing the river water quality. Seven sampling sites of the main river and five sampling sites from its tributaries were selected considering the pollution impact on various activities. Sampling sites has been selected 58 km away from river mouth to landside up to Avissawella
Evaluation of the water quality of Kelani River using Water Quality Index
Evaluation of the water quality of Kelani River using Water Quality Index
pH, Turbidity, Dissolved Oxygen, Biochemical Oxygen Demand, Chemical Oxygen Demand, Nitrate, Phosphate and dissolved form of heavy metal in water such as Chromium and Lead were considered to evaluate water quality index for all sampling locations in line with the proposed CEA’s (Central Environmental Authority) inland water quality standards by using water quality data from 2010 to 2019. Since microbiological analysis were not carried out consistently for the total monitoring period, that was not considered for the evaluation of Water Quality index. Faecal coliform and the turbidity are always exceeded the standards in all sampling locations during total monitoring period.
Summary description of the water quality of Kelani River
Summary description of the water quality of Kelani River
The anthropogenic activity such as gem mining and river sand mining causes severe damage to the river bed and increases the turbidity of the river water in all sampling location. Microbiological contamination and the turbidity are major sources of water pollution in Kelani river. Turbidity (which is a measure of the light-transmitting properties of the water) is also a measure of the suspended particulate matter in the water and depends on the fineness and concentration of particles. The variation of turbidity is always associated with the incoming suspension of sediment particle flowing along with the storm water may be due to mining activities of the upstream of the river as well the continuous rain. Turbidity which implies the activity relates to sand mining, Gem mining and impact on uncontrollable urban runoff is always exceeded the standard value throughout the monitoring period in all sampling locations
Least no of parameters and the lowest frequency of deviation from the standard value are recorded in sampling sites at Hanwella and Welivita . Highest no of parameters and the frequencies of deviation from the standards are reported in sampling sites at Seethawake Ferry and Victoria bridge. The water Quality index of these two locations is lower and the ecological condition of the water is poor.
The highest WQI score in the Kelani river was detected at the middle of the river located at Welivita (68) the lowest score was detected at the sampling site at Thulduwa (46) and Seethawake (51).
The quality of the river water at Thulduwa and seethawake ferry had inferior quality with compare to the lower reach of river and rapidly deteriorated during past three years rapidly. The ecological condition of two sampling sites indicates that the water quality is poor. The sampling site at Seethawake ferry gets the industrial waste water from the Seethawake industrial zone. The parameters always exceed are COD (37%), BOD (13%) Dissolved Oxygen (43%) and Heavy metals (7%) other than the turbidity.
The sampling sites in the middle of the rivers that is Pugoda Ferry, Hanwella Bridge, and kaduwela Bridge had a superior water quality compared to the its upstream, may be due to the dilution effect receiving waters from tributaries, . The highest WQI is reported from the sampling sites at Welivita and Pugoda ferry. The ecological condition of these two locations is fair.
The WQI of the main tributaries such as Wak Oya, Pugoda Ela are in the range of 51-59 and the ecological condition is poor.
The worst, very poor ecological condition is reported from the sampling sites at Raggahawatte which flows contaminated industrial waste water from Biyagama Industrial Zone. Most of parameters were exceeded the standard value during the total monitoring period which implies the industrial pollution. The parameters always exceed are COD (36%), BOD (7%) Dissolved Oxygen (27%) and Heavy metals (7%) other than the turbidity.
The secondly contaminated tributary is Ma Oya. It is mostly polluted due to the discharge of organic waste. Most of the time, the parameters always exceed are COD (13%), BOD (60%) Dissolved Oxygen (80%) and Heavy metals (7%) other that the turbidity.
Microbiological pollutants in some locations may possibly due to the disposal of untreated or partially treated sewage (example, from household latrines and hotels, etc. occurring on the banks). Water Quality indexes evaluated annually is clearly indicated that the river water is deteriorated gradually in all sampling locations.
Water Pollution & Its Impacts
Water Pollution & Its Impacts
Humans have established communities and flourished around sources of clean, drinkable water since the beginning of time. It’s vital to our survival. Do you know that you can survive several days without food but not without water? It’s heartbreaking to know that millions of people worldwide do not have access to this most basic need, and are dying of thirst and water borne diseases. Freshwater sources around the world are threatened by water pollution. Not only are we managing our resources poorly through wastage, we are also thoughtlessly dirtying it.
Sources of Pollution
Sources of Pollution
The main sources of water pollution are the following:
Discharge of untreated Raw Sewage from households and factories
Chemicals dumped from Factories
Agricultural run-offs that make their way into our rivers and streams and groundwater sources
Urbanization
The rising use of synthetic organic substances
Oil Spills
Acid Rain caused by the burning of Fossil Fuels
Human littering in rivers, oceans, lakes and other bodies of water. Harmful litter includes plastics, aluminum, glass and Styrofoam. Almost everything that is a byproduct of our civilization is polluting our drinking water. Governments, through various Clean Water Acts and water resource policies have sought to regulate the discharges of pollutants in the water to minimize pollution and contamination. From 1990 to 2006, an additional 1.6 billion people had access to safe drinking water. But we are not acting fast enough and most factories still find a way to dump their toxic wastes in the sea, unseen.
Effect of Polluted Water on Humans
Effect of Polluted Water on Humans
How does water pollution affect humans?
How does water pollution affect humans?
Try drinking untreated water nowadays and your body will immediately react to it. You will get a stomach ache at the least. Water-borne diseases account for the deaths of 3,575,000 people a year! That’s equivalent to a jumbo jet crashing every hour, and the majority of these are children.
Infectious diseases can be spread through contaminated water. Some of these water-borne diseases are Typhoid, Cholera, Paratyphoid Fever, Dysentery, Jaundice, Amoebiasis and Malaria.
Chemicals in the water also have negative effects on our health.
Pesticides – can damage the nervous system and cause cancer because of the carbonates and organophosphates that they contain. Chlorides can cause reproductive and endocrinal damage.
Nitrates – are especially dangerous to babies that drink formula milk. It restricts the amount of oxygen in the brain and cause the “blue baby” syndrome.
Lead – can accumulate in the body and damage the central nervous system.
Arsenic – causes liver damage, skin cancer and vascular diseases
Fluorides - in excessive amounts can make your teeth yellow and cause damage to the spinal cord.
Petrochemicals – even with very low exposure, can cause cancer.
These are just to name a few.
Let’s do our Part…
Water pollution is a known threat to humans and we can do our part to help keep our waters clean.
Don’t throw litter in the ocean. Don’t dispose of chemicals, paint, in water supplies and drains. If you see anyone throwing litter into any body of water, report it to the authorities. Help increase awareness by educating your children and increasing awareness within your community. There’s a long way to go, but as we mature as a society and as our technologies progress, we can improve our methods of protecting our water supply. Right now, everyone just needs to do their share, from their end.
Industrial Zones in the Kelani River basin
Industrial Zones in the Kelani River basin
Through these maps we can see that various kinds of industries have been spread in the Kelani river basin zone. So, probably wastages of these industries might be directly or indirectly emitted to the river.
Water Quality Categorization in Kelani River Basin
Water Quality Categorization in Kelani River Basin
Category A:
Water source for partial treatment
Water Supply Category 1. For waters whose waterbodies remain uninhabited or otherwise protected, and which require only approved partial treatment process commonly adopting simple physical treatment and disinfection process to meet the National Drinking Water Quality Standards. The values are also consonant with the Sri Lanka Standard 722:1985 on Tolerance Limits for Inland Surface waters used as raw water for public water supply. These waters shall also include pristine water with outstanding quality that may be found within national park and other protected areas.
Category B:
Bathing and contact recreational water
Recreational Water Category. For primary and secondary contact recreational activities such as swimming and diving. The use of waters includes drinking purposes without appropriate treatment process.
Category C:
Fish and Aquatic Life Water
Fishery Waters Category. For commercial and municipal fishing waters which are widely used for fishing purpose by local fisher folk and other waterbodies which are locally known or identified as habitats of fishes or other aquatic products being consumed by humans or are being used for the propagation of such.
Category D:
Water source for general treatment
Water Supply Category II. For waters whose quality requires with full treatment process commonly adopting normal physical and chemical treatment accompanied by disinfection as designated by NWS&DB in order to meet the national Drinking Water Quality Standards.
Category E:
Irrigation & Agriculture
Agricultural and other uses Category. For compatible agricultural uses (irrigation, livestock watering, etc.) and other uses.
Category F:
Minimum Water Quality
The minimum water quality of the nation’s waterbody. This would include those used for navigational purposes, etc.
With the lock down series came up with COVID-19 pandemic, water quality of Kelani river basin was somewhat noticeably increased due to shutting down of industries. That is the reason we can identify that caused to increase water quality level.
As we observed, The Kelani river is majorly polluted by the dischargement of untreated sewage from households and factories. Though the factories were closed with the lockdown series, people were impounded to their houses and the emission of household wastages was not reduced. As well though the country was locked down the government let the farmers do cultivations. So, we can't expect any abatement of Agricultural run-offs that make their way into our rivers and streams and groundwater sources.
But, however, according to our analysis, the change of water quality in the Kelani river basin during the lockdown series was not much affected to the human activities in communities of minority, low-income, tribal, and indigenous populations.
Resources
Central Environmental Authority of Sri Lanka - Industrial Data
Central Environmental Authority of Sri Lanka - Land use Data
Central Environmental Authority of Sri Lanka - EPL categorization
United Nation Environment Programme - data on Water Pollution (global)
United Nation Environment Programme - data on Water Pollution (Sri Lanka)
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