Wonders of the world: Spiders

Tree spider

When I was a child like my other friends, I was scared of spiders. Even now when I see a spider in my room, certainly I do not scream, but yet, I avoid them and try to chase them out from my room. When I grew up little by little, I wanted to get rid of this fear and crazy imaginations about spiders, so I started reading about spiders in order to get familiarize with these little fascinating creatures.

We all know that spiders are disliked by many people due to their lack of knowledge about spiders. According to the taxonomy of spiders, they belong to the class Arachnida Phylum Arthropoda. These spiders are carnivores which mean they feed on small insects or flesh. They do it by trapping their pray using their web or by hunting on ground. In addition, these spiders can be seen all over the world except in air since they do not have wings to fly and in ocean since they are air-breathing animals. Yes, there are some spiders who can live under water such as Diving Bell Spider ( Argyroneta Aquatica) but they also need air. In this case they trap air in a bubble held by hairs on its abdomen and legs.

Another reason is their size and the appearance which give an expression that they should not be petted or loved, they are venomous and dangerous. When we consider about their size, most spiders are relatively small (2-10 mm) but there are exceptions like Tarantula whose body length will extend up to 80-90 mm. Even though size varies from one spider species to another, their body consists of two main parts. First part is the “Cephalothoraxe” (Prosoma) which is the anterior part and the other part which is the posterior part, known as “Abdomen” (Opisthosoma)

CONSTRUCTED WETLANDS AS A METHOD OF WASTEWATER TREATMENT

          Since most chemical reactions take place in water based medium, water plays a major role in industrial world. With the polar nature of water it easily gets polluted from those chemical and biological ingredients use in manufacturing process. This polluted water is called industrial effluents or simply the wastewater. Since industrial wastewater contain toxic chemical compounds like Cyanides, biological waste like plant materials and pathogens, toxic heavy metals like Cadmium, Lead, exceeding the accepted levels for human use. When this wastewater released in to natural water bodies it may result social and health problems to the people living around the water resource and also to the people who use it for day today work. 

Minamata Disease (methylmercury poisoning) on Public Health & Social Justice 

socialmedicine.org

In early days people tends to release this waste water to natural water bodies without a proper treatment. Therefore in early days outbreaks due to hazards waste were common. Minamata outbreak in Japan is such a disaster coursed by not having a proper treatment for wastewater. Wastewater treatment is an expensive process, if we are using conventional methods like chemical precipitation, Ion exchange; Reverse Osmosis and Electro dialysis. Not only they are expensive but also they produce toxic sludge therefore small industries won’t consider about having a wastewater treatment plant within their manufacturing plants due to the high production cost. Instead they release wastewater to the nearby water stream without treating it.

MOON PLAINS SANITARY LANDFILL

In Sri Lanka, disposal of waste is a major environmental and social problem, which leads to several health problems like dengue in urban areas. As responsible government, Sri Lanka should have a proper way of disposing of waste. But in Sri Lanka, disposal of waste is mainly done by maintaining an open dump site, which will cause many environmental and health problems. Instead of open dumpsites, one proper way of deposing waste is maintaining a sanitary landfill. Moon Plains is one such sanitary landfill, which is started in 1996 by the Nuwara Eliya municipal council as a normal dumping site, and converted in to a sanitary landfill in 2003 with the help of JICA foundation. This land fill is located in a valley surrounded by a cultivated Eucalyptus forest, which is owned by the forest department, outside the Nuwara Eliya municipal council. And it is close to a water stream which provides water to a reservoir called Bomuraella which used for domestic and agricultural purposes by the people who are live around the reservoir. Initially this valley is used as an open dump site by the Municipal council without taking any environmental protection measures.

This valley which is 400m long and 30-40 meter deep is a part of 5.8ha catchment. And this valley consists of sandy clay soil and bed rock is a hard rock. Since Nuwara Eliya located in wet zone annual rain fall is around 2700mm therefore it gives rice to a seasonal stream which connects to the close by stream. When all the Municipal waste, Hospital waste and industrial waste is dump without any environmental protection measures it can easily contaminate that water stream and the reservoir causing serious environmental and health care problems to the society.

COAL FIRED ELECTRICITY GENERATION.

              Energy, we all need it to do a work. As humans we use energy stored in our body. But most of the time energy stored in our body is not sufficient enough to finish the required work. Therefore we use machines to do our work. Most of these machines driven by electricity which makes electricity to play a major role in the form of energy for development of a country. Electricity generation required an efficient energy source. Energy sources that we use today is limited resulting a global problem called energy crisis.s

              Hydro power is the most common energy source that people familiar with the electricity generation in Sri Lanka. Other than that developed countries use nuclear energy to generate electricity. Fossil fuels, geothermal energy is also using for electricity generation. Due to the modern climatic changes hydro power stations cannot operate at their maximum capacity. And Nuclear power plants need more advanced technology and more capital which cannot afford by developing country like Sri Lanka, which lead to find a convenient alternative energy source to generate electricity. Such convenient alternative energy source is Coal. Coal is a solid fossil fuel which containing Carbon and it is the most impure of fuels, its impurities range from trace quantities of many metals including uranium and thorium to much larger quantities of aluminum and Iron to still larger quantities of impurities of such as Sulfur. 

Wonders of the world (Firefly bug)

      Few years back when I was in grade one, me and my friends used to collect Tortoise beetles as our hobby. Whenever we caught a new Tortoise beetle which differed from others we brought them to school and showed them to others by saying that we got a new Tortoise beetles that you guys don’t have. And we explained how we caught them, from where we caught them, things they eat and that kind of funny stuff. Those are wonderful memories and i'm sure you also have those kinds of sweet memories with you. Back to story, but one day I caught a bug little bit different from Tortoise beetles. Usually, Tortoise beetles are hemispherical in shape and have bright colors. But the one that I caught was little bit elongated and thin. So I thought I caught a new Tortoise beetle that none of my friends have caught early. Since my friends don’t have such a Tortoise beetle with them, I was so happy. So that I can show my new Tortoise beetle and tell them about it.

I put my new friend with my other Tortoise beetles. So that I can take it to school on the next day. But at night I suddenly got waken up by a strange light emitted from my Tortoise beetle container. I was afraid and I called my mother to tell about this. She told me that she will explain it in the morning and asked me to sleep. But I couldn’t sleep all that night. 

e-Waste/ Waste Electronic and Electrical Equipment

            e-Waste or waste electronic and electrical equipment is a major environmental issue that is faced by developing countries even though they produce a small amount of electronic products. These e-Wastes can be either electronic items such as computers, televisions that are discarded, donated or sold by the original owner.

 These e-Wastes contain several harmful pollutants like large quantities of epoxy resins, fiberglass, PCBs, PVC (polyvinyl chlorides), thermosetting plastics, lead, tin, copper, silicon, beryllium, carbon, iron and aluminum and also elements found in small amounts like cadmium, mercury, and thallium. They also contain elements found in trace amounts like americium, antimony, arsenic, barium, bismuth, boron, cobalt, europium, gallium, germanium, gold, indium, lithium, manganese, nickel, niobium, palladium, platinum, rhodium, ruthenium, selenium, silver, tantalum, terbium, thorium, titanium, vanadium, and yttrium.

PCB (Poly Chlorinated Biphenyl) Pollution

                PCBs or in other words, polychlorinated biphenyls are widely used as organic compounds and as dielectric fluids in transformers and capacitors. PCBs are organic compounds that contain 1-10 chlorine atoms attaché to biphenyl group (C₁₂H_10-xCl_x) and they are formed by electrophilic chlorination of biphenyl with chlorine gas. PCBs or Polychlorinated biphenyls were first commercially used in 1929 as a “safer” cooling and as an insulating fluid in electrical industry.

                These PCBs are not only used as coolants and insulating fluid but they are also used as components in early light fittings and in electrical transformers. Besides all these usages, PCBs are also used as plasticizers in paint and cement, as stabilizing additives in flexible PVC coating, in electrical wiring and in electronic components. Since PCBs have high viscosity, high flashing point and high thermal conductivity they can be used for cutting oils, as reactive flame retardants, lubricant oils, hydraulic fluids and sealants. And PCBs are organic compounds that contain Chlorine in it and therefore can also be used as pesticide.

Greenhouse effect and Global warming

Global warming is one of the worst environmental problems that the modern world is facing due to several unfavorable human behaviors. According to scientists and scientific research, global warming increases the average temperature of the earth’s near surface, air and the ocean. As a result of global warming unwonted environmental effects take place, such as the rise of sea level which causes several problems to small islands like Maldives islands.  Because of the global warming, there can be changes in the amount of precipitation, extreme weather conditions like droughts and heat waves.  And also global warming can affect the biodiversity of the world by eliminating animal and plant species due to the shifting of the temperature.

For this worst environmental effect, the main reason is the human activities. For instance, after the industrial revolution, people started to use more fossil fuels which gave rise to greenhouse gases. These greenhouse gases lead to a natural phenomena called greenhouse effect, which helps us live in a warmer place or on the other hand which warms the earth beyond its effective temperature. Without greenhouse effect the earth surface will be much cooler than what we are experiencing today.

Climatic Changes

            Climate basically includes changes in temperature, humidity, atmospheric pressure, wind, precipitation of that place from a long period of time, whereas weather is the present condition of these elements.  And we all know that climate is changing from place to place, since climate is affected by the latitude, terrain, altitude and the nearby water bodies. Therefore, we can say that climate is a prediction made by observing the weather of a place for a long period of time; these predictions of climate, are very important to human life because the distribution of natural resources like forest/ vegetation depends on the climatic factors. Therefore, even a slight change in the climate can influence human life at a greater degree.

             Climatic changes are long term changes in the statistical distribution of weather patterns over period of time that range from decades to millions of years. The United Nations framework conversion on climatic changes defines climatic changes as “A change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods”.  Climatic changes occur mainly due to the human behaviors that destroy the environment. Other than that, variation of solar radiation, deviation in the earth orbit, mountain building and continental drift contribute to the present undesirable climatic changes like extreme weather conditions.

CHRONIC KIDNEY DISEASE IN SRI LANKA

Chronic kidney disease is a major health problem in Sri Lanka since in last 8-10 years. CKDu or chronic kidney disease of unknown aetiology is characteristic from other kidney disease by its slow progressive asymptomatic development. This disease start at a younger age group and it is common among people who engaged in agriculture typically around age 40-60 years

In chronic kidney disease kidney dose not usually fail at once instead it slowly stepwise fail to perform it tasks  chronic kidney disease involves 5 stages. Therefore stage 5 chronic kidney disease is also referred to as kidney failure, end-stage kidney disease, or end-stage renal disease, wherein there is total or near-total loss of kidney function. There is dangerous accumulation of water, waste, and toxic substances, and most individuals in this stage of kidney disease need dialysis or transplantation to stay alive.