Compact Fluorescent Lamps (CFLs) are being used approximately for more than 35 years, but they became very popular during the last decade because of their lesser energy consumption (save energy about 75%), becoming cheaper, reduces carbon dioxide emissions, and it has long life span compared to general incandescent lamp [1]. The production facilities of CFLs causes mercury emission to the environment that could be about 2.4 mg [2]. During the last 20 years the manufacturers have significantly minimized the amount of mercury (Hg) used in Fluorescent lamps (FLs). Because Hg is a vital component, it cannot be excluded totally from FLs [3]. CFLs contain a tiny quantity of Hg which is a highly toxic metal; when they are broken or damaged while retailing, handling, shipping, and during use. Further, people may expose to the mercury vapor emissions from CFLs. Inhalation from cracked or broken CFLs is the main method of exposure to people. 80–97% of the sniffed elemental Hg is soaked up in the body via the lungs which can easily be scattered in the atmosphere [4]. As a result, exposure to mercury can result in Behavioral and Neurological disorders such as: Insomnia, Memory Loss, Tremors, Emotional Liability, Headaches, Cancer, and Neuromuscular changes [5]. It exerts toxicity on different human organs, including the renal, central nervous, immune, reproduction and cardiovascular system [6]. Nervous system of children, infants and foetuses is highly sensitive and is susceptible to ecological imbalances particularly, it impairs the neurological development. Mercury lies and gathers in the brain, when it gets into the body of human beings [5]. Manufacture of CFLs is rated to be around 1.5 billion lamps annually [1]. Modern CFLs hold an average of 1.5–3.5 mg per lamp [1]. But scientific literature show that, the analyzed 40% of the lamps were containing Hg more than the standard limit [7]. However, mercury pollution resulting from CFLs manufactures can affect significantly and negatively on the safety growth of agriculture production, tea, fruit, and vegetable products [8]. The disposal of CFL causes the release of Hg into the atmosphere. After being released into the atmosphere the Hg could be converted into Methyl-mercury that is highly toxic. They may become the part of food chain easily. In watery sediments inorganic mercury could be methylated, consequently methyl-mercury is bioaccumulated to elevated level in seafood chains. Thus, the extremely poisonous methyl-mercury is found in maximum concentrations in predatory fish organs of extended existence in oceans, rivers and ponds.

CFLs are normally a glass tube coated with Phosphor and at both ends there are electrodes, an inert gas (usually argon) and a tiny amount of Hg (partially in the form of vapor) sealed in the tube. When electric current passes through the electrodes the mercury vapor is excited, and the excited mercury emits the ultraviolet radiation which is transformed by the phosphor coating to visible illumination. Fluorescent lamps are one of the kinds of discharge lamps, because generation of the light occurs in vapor or gas by an electric discharge. Moreover, in order to convert the ultraviolet light into visible light the glass tube is coated with phosphor. Australian radiation protection and nuclear safety agency suggests to keep the distance between CFLs and human beings at at least 30 cm especially for desktop application, otherwise ultraviolet radiation might cause increased concern [9] . In order to achieve long lifetimes for CFLs, sufficient quantity of mercury is needed. Mercury could be placed in the lamps by different ways such as solid, pellet amalgam or liquid dosing technologies [10]. The form of Hg used in CFLs is called Elemental mercury that could evaporate at room temperature because of its low vapor pressure [10]. Studies showed that the released rate of Hg depends on the temperature of the room [10]. After the breakage within a very short span of time initially 180 μg of mercury is released (e.g. 1 s) [4]. Elemental Hg is dissolvable grease hence it can pass through several membranes in the body such as placenta and the bloodbrain barrier. Studies showed that around 70%-85% of sniffed Hg vapor is soaked up via the lungs into the bloodstream [14]. In addition, the transportation of Hg from the pharynx to the encephalon via olfactory neurons has been demonstrated. Mercury is distributed all through the human body which can be collected in the kidneys and the encephalon producing variations in renal and neurological performances [10].

The presence of CFL manufacturing plant affects the flora and fauna of the surroundings. Released Hg from manufacturing facilities settles on the superficies of vegetables and as a result increases the concentration of the mercury. In the vegetable samples collected from CFLs manufacturing locations the mean of total mercury and methyl-mercury concentrations were significantly higher than those collected from the controlled sites [8]. Besides that, concentrations of total mercury were 50% higher in the vegetables than China's National Standard, which suggests that Hg emission from CFLs industrialization was a reason of contamination. In stream sediments the concentration of methyl-mercury was commonly higher than that of cultivation dusts for the corresponding areas. From the reported studies it has been identified that mercury evaporates very easily in soils as compared to the sediments. A pictorial view of Hg releasing into the environment and becoming a part of the food chain is presented in Figure 1. When mercury is released from CFL industry or any other source, it is deposited into the soil and ocean, lakes, ponds etc. This mercury is converted into methyl-mercury by certain bacteria which are present in the soil. Then it is taken up by small organisms such as plants, fishes and other aquatic animals. When the bigger fish eat the small aquatic animals, methyl-mercury is transferred to them and become more concentrated. Such process is called “Bioaccumulation” [8]. When these plants, in the form of vegetables, and fishes when eaten by human beings, the methyl-mercury is transferred to them and causes disorders especially to the fetus and infants, inducing nervous system disorders. Hence proper disposal of Hg is sought.

Figure 1. Mercury releasing into the environment

CFL industry uses about 80% Hg in the form of liquid alternatively to mercury amalgam or pellets in the industrial process which is a very high amount of Hg being consumed for each lamp. Dosing Hg unavoidably inside the CFLs leads to the release of the Hg fumes. The conventional liquid Hg dosing method has poor accuracy and reliability either automatically or manually. Liquid mercury dosing has been substituted by modern technologies, (because of safety, accuracy and very tiny controlled quantity delivery inside the CFLs) while using Hg dispensers or glass capsules, depending on Hg alloys. The developed manufacturing methods significantly decrease the mercury emissions to the environment while CFLs production, also efficiently employ the least Hg contents in lamps. Mercury emissions might happen from transfer and purification of mercury, broken lamps, mercury injection operation, spills and waste materials in fluorescent lamp plants [15-25]. The released mercury in the production plants is hazardous for the laborers, likewise causes contamination to the working areas. The workers' primary route of exposure during inhalation of Hg fume is that produced chiefly during dosing or from ran off mercury or dropped Hg. Mercury fume is lesser sucked up via the skin of human beings, however easily sucked up via the alveoli and transported through the blood to different organs [6, 26-30].Accumulation of Hg in the human body is to a lesser extent in the kidneys and primarily in the brain whereas removal of mercury from the body happens at various degrees in various parts of the body, with the usual half-life of 60 days for the body completely [6]. The liquid mercury dosing in CFLs leads to significant releases of mercury fumes, because of the volume of mercury in the air from the plants. Studies showed that the workers in CFL manufacturing facilities show typical signs of poisoning due to mercury because of chronic contact with mercury fume, for example, hypertonia, inflammation of gums, and tremors [6]. Improvement in the dosing technology significantly improved the signs of loss of sensation of limbs and muscle twitching showed by the workers, though gingivitis, neurasthenia, and hypotonia still develop greatly. Moreover, in these workers more impairments and neuropsychological issues were commonly associated with the presence of mercury. The incidence of diseases associated to long-term professional mercurialism were also detected. Consequently, these outcomes prove that CFLs manufacture exhibit major problems related to heath in the workers and long-term mercury toxicity is dominant among employees when they interact with mercury [30- 34].

In the literature it is seen that the place where CFL breakage happened was in a typical room of 27 m³ (divided into two zones: higher zone from 30 cm to the roof and lower zone from the floor to 30cm height which is the breath-taking region of babies and children where mercury concentrations are relatively higher) [4]. In between the lower region of the room and the outer atmosphere no air exchange was assumed, only in the lower region emissions occurred, where the breakage of CFL happens. The greater amount of mercury is inhaled during the initial moments when the CFL is broken. During the initial time of lamp breakage, mercury exposure is much higher to the babies or children as compared to the adults because they breathe in the lower region of the room [4]. While initial 4 hours after lamp breakage a 10- degree increase in temperature of atmosphere inside the room could lead to 50% higher the release of mercury in the air [4]. This situation is probable in the regions of Arabian Gulf where the temperature of the atmosphere increases greatly during summer. At the interior region of the room mercury concentration becomes raised swiftly when CFL breaks, up to 60μg/m³ and then because of mixing with the air present in upper region and continuous ventilation from outside, concentration tends to decrease [4]. In the upper region the highest point is much lesser (about nearly 5 μg/m³) and soon (within 3 hours), mercury becomes equiponderant. In dust the concentration is about 120 μg/g -dust, decreasing slowly as compared to the concentration of Hg present inside the room. While Hg emission in the solid substances remains very low (10 times) as compared to the concentration of mercury present in gas (very low in both zones) [4]. Mercury fumes can remain inside the room for 31 hours at the lower region and upto 23 hours in the highest zone after CFLs breakage in case it is not removed [4]. The concentration of Hg between both the regions start to become equivalent after the first hour. Studies have been conducted using a 2L container made of Teflon with CFLs which has been broken in order to measure the rate at which mercury vapor is released over time [10]. Furthermore, two CFLs types were used, a 9W lamp with 5.0 mg of mercury and a 13W lamp with 4.5 mg of mercur y [10]. The mercur y concentrations were measured utilizing mercur y analyzer, RA 915+ (equipment). At first the rate of emission of mercury vapor was high and it has been slump within 24-h and released less than or equal to 1% of the whole Hg in the lamp in the form of vapor within the first hour [10]. Through the initial 24- hours, the 9W lamp had released 1.9% and the 13W lamp had released 11.1% from the whole Hg inside it [10] . Thus, both lamps were releasing mercury continuously for at least four days (the total amount of Hg in the lamp as specified by the lamp manufacturer). Moreover, the 13W lamp had released an amount of 30% from the whole Hg inside the lamp or 1.34 mg through 4 days [10]. The liquid drops of mercury, had increased in the rate of release to the bigger surface area of mercury adsorbed onto the phosphor and lamp components in CFLs. In another research, inside a 146L (32 gallon) container made of plastic the fluorescent tubes were broken and the vapor of Hg concentration was monitored inside the container and measurements were taken under different temperatures around, 5, 15, and 30 Celsius for each trial in the room. During the initial 8h the mercury was converted into vapor form and over a 14-day period 17-40% of the whole Hg that existed in CFLs vaporized about one-third. The concentration of Hg increased immediately if lamp or tube broken on shag carpet or wooden surface. However, the concentration falls down around 300ng/m³ in 10 minutes or less if windows are opened and pieces of broken tube are cleaned up [11]. Overall these analysis show that emission of Hg from broken CFLs depends on time, amount of Hg, manufacturer and the size and power of the lamp.

If there are no preventative actions taken after the breakage of the lamp (for example; to raise the interior and exterior air exchange ratio), it might remain above the threshold average hourly concentrations of Hg for the first 3–4 h [4]. The exchange ratio of the air should be higher because it will decrease the exposure and as a result, there would be lesser hazard to human beings. Removing mercury is strongly recommended as soon as possible. The most efficient method to remove the contaminants from the interior air is ventilation. Hence, it is important for all those buildings which are having mechanical or natural arrangements for ventilation, because circulation of air is essential for healthy indoor environments [4]. The concentration of Hg can decrease readily if the rate of ventilation is higher and the room or location has been left ventilated for a long time. Within the 2nd hour the concentration of Hg falls under the threshold in case of higher ventilation [4]. Carefully removing the pieces of the broken lamp and remaining drops of Hg might drastically decrease the exposure. There are many scenarios for ventilation and cleaning-up regarding Hg after CFLs fracture, the most effective propositions are as follows:

Immediately open every outer door and window. After the fracture event and before cleaning up the pieces human beings should be scrammed as soon as possible and should avoid being closer to the zone for 15–30 min because, the level of Hg of the air in the zone will reduce gradually [4]. Immediately after the breakage of CFL the room must be left for 15 minutes minimally [5]. Containers should be used to carry the shards and powder in order to clean up the contaminated zone. Sealed sacks or crocks must be used to place the remaining material and cleaning with wipes is strongly and immediately required. Cleaning otherwise, with a broom, or vacuuming the broken lamp on hard surface is hazardous because the Hg will disseminate over the region [5]. If the glass shards have been removed after the breakage from the carpet the discharge of Hg could reduce by 67% [10]. A recent study shows that under poor ventilation condition in a regular room the mercury level can exceed the safe human exposure limit and once the CFLs is broken it can emit mercury fume constantly for over 10 weeks [6]. Actual life situations could differ from experiments that are used to find these outcomes, for example range of area, area temperature, lamp usage, more use of vacuum, and material used to cover the floor.

A tiny amount of mercury poses no risk to the ambience and human health as long as fluorescent lamps remain intact, while individuals might suffer from harmful effects of escaped mercury vapor from broken lamps. However, the used-up fluorescent lamps finally breakdown and the mercury which is present inside will escape into the trash tributary and the ambience. When broken FL is openly dumped, mercury vapor is released to the atmosphere. The released mercury is transported to the soil by rain droplets which unbinds the mercury from broken parts of the lamp. Experimentally it has been proved that 0.8% of the whole Hg was discharged from crushed FL with 0.5- meter of soil covers over 3 weeks duration [6]. Buried in landfills the mercury in fluorescent lamps can escape out into nearby surroundings, during leakage, into the fluid or gas in the disposal site of waste materials. In the absence of Hg emission controls in fluorescent lamps up to 90% of the mercury might escape out into the atmosphere when the lamp is burnt, because it is volatile Recycling or recovery at the end of the life of CFLs can greatly reduce the effects of mercury. It is quite possible that during cleaning of municipal solid waste, mercury escapes from broken lamps, to the atmosphere. Thus to prevent breakage of fluorescent lamps, it is important to take care of the lamps while storing or transporting it from one place to another.

The recycling of hazardous products could decrease the pollution to the environment and at the same time save space in landfill. Moreover, recycling could result in reduction of utilization of raw material. Any Hg-containing lamp if damaged, broken or having a leakage could contaminate the ambience by releasing Hg. The emission of total mercury in the lamp varies from 2-14% depending on the lamp life and manufacturing [3]. Mercury is present in different forms, it might be as a liquid or in vapor form. Mercury releases as vapor over hours and days after the lamp is broken [7]. It is measured by studies that after the breakage of the lamp there is an immediate release of mercury in vapor form to the atmosphere approximately between 17-40% through 14 days period [12]. Depending on the manufacturer, type and lamp life the ratio of mercury in SFLs (Spent Flourescent Lamps) could differ [3]. Based on the studies it is important that FLs must be recycled. Otherwise, sending massive number of SFLs to the domestic landfills will release a huge amount of Hg to the surrounding environment. Therefore, air, waters and soil will become polluted [5]. At the same time, the spent fluorescent lamps have precious materials including, metal end caps, glass tube and mercury. Therefore, recycling of spent fluorescent lamps is strongly required, it has been shown by the studies that in the USA approximate cost for recycling CFLs per lamp is 0.35-1.0 US $ and 0.15-1.0 US $ additional for transporting and collecting the lamps [2]. The rate of recycling in Germany is approximately 100% and there are 20 plants for recycling and 220 points for collection [2]. Based on the hours of operation, year of manufacture and the place where distribution of mercury and its content differ in FLs [13]. Compared to other components of SFL the concentration of mercury is very high in phosphor powder [3]. As the lamp reaches the end of its life, higher than 13.66% of mercury disperses on the lamp glass hence broken lamps are in hazardous waste category, and about 85.76% of mercury in CFLs substitutes is part of the phosphor powder [13]. The energy and material used for recycling process is less than that for non-recycling process (process used to classify the waste as nonhazardous to be able for disposal) [12]. Moreover, emission of mercury for recycling process is less than that for non-recycling process [12], because the existing technology used for recycling does not exceed the standard limit of mercury vapor emission to the ambient air [12]. Therefore, it is acceptable for the glass of the lamp to be categorized as a non-hazardous waste if all phosphor powder attached to the glass are eliminated and brought down to the allowable limits. For recycling fluorescent lamps in advanced facilities there are two main methods as explained in the following sections.

7.1 End Cutting Method

• The end cutting method needs sorting of the linear fluorescent lamps preliminary based on the diameter and length. The metallic end-caps are removed first, by cutting, then the luminescent powder of the glass is flushed out with jets of compressed air. The glass is then clean to be milled. The different products of milling are stored in separate containers and sent to the stores.

7.2 Crushing Method

• The crushing method does not require preliminary sorting of lamps, and it can be utilized both for CFLs or FLs. Lamps (in batches) are placed into a crusher or shredder and the output depends on the purpose of the procedure.

It is preferable that end-cutting technique should be applied for SFL recycling to isolate the glass and mercury free end-cap because there is a vacuum system (activated carbon is applied while running the process in order to control the concentration of Hg) to prevent mercury vapor emission to the environment [3]. Moreover, using end-cutting process for recycling of phosphor powder and aluminum is possible because phosphor powder could be recovered without fragments of tube and aluminum and base-cap respectively [3]. However, lamp storage areas might become polluted if a number of broken lamps exist in the containers because while transfer lamps are shaken, or during handling lamp breakage might be possible, and usually storage areas are not suitable for such unique activities. Lamp sorting should be done before introducing them to the machine (end cut), because of it's hazardous operation. While sorting, some lamps might break or sometimes there might be broken lamps before being sorted. Hence, exposure of human beings for short period may exceed the safety levels [7]. At this stage, the level of pollution greatly depends on careful sorting of lamps in order to avoid breakage. If breakage occurs accidently then it has to be considered as to how it should be managed, and broken lamps storage facilities need to be planned. In order to avoid the pollution of the environment of the area, the end-cut is bounded by low pressure confinement technique [7] since highly toxic concentrations of mercury vapor, lead and especially inhalable dust have been measured in the atmosphere. For end-cutting method it is significantly required to work under high ventilation rate, because the released mercury vapor declines in working zone as rate of air flow rises [7]. Moreover, operator's exposure to contaminations might occur while in the maintenance or cleaning stages, hence there is a requirement of special equipment for respiration and protection from unsafe dust and mercury vapor [7]. Operators occupied on crushing processes are unprotected from metallic contaminants more than those occupied on end cut processes [7]. Confinement of crusher is vital because emission of mercury from lamp crushing greatly depends on it, and at the meantime there is no decontamination procedures being implemented for the same. Crushing processes are not ecologically friendly compared to end cut processes hence it should not be supported as a final decision [7]. The most contaminating point is at the output where higher than 80% of the total mercury contained in the lamp is absorbed in luminescent powders [7]. Laborers working daily in recycling sector for 8 hours could have an exposure to the pollutants because of the different activities (especially operator's skin becomes polluted) [7]. Mainly operators exposed to contaminated zones of treatment plant are those which are at feeding the machine and at the output. While running the process there is continued emission from the output because of the contamination while feeding and handling the lamps mainly caused by enormous numbers of broken lamps (mercury vapor escapes) [7]. Before the working shift it has been noticed that laborers do not rinse their faces and hands methodically hence they could be exposed to the pollution indirectly through oral exposure [7]. The measurements clearly show that every stage of the recycling processes is contaminated. In addition, effects on the laborers depend on the task they perform. Suggested recommendations to improve the situation are: Airtight vessels must be used for broken lamps and at output stage where mercury vapor releases. Efficient ventilation processes must be implemented for every recycling stage at workplace. In order to keep laborers protected at the input zone there must be a semiautomatic or vacuum lock feed system which has to be implemented. There should be devices at particular points of work area with alarming system to measure the level of the mercury in order to control it continuously. For hazardous activities such as maintenance and cleaning operations there is a need for each laborer for appropriate defensive equipment. Eventually, to make laborers’ life easy and protective there must be mandatory hand washing, shower, and facilities for changing the clothes.

The usage of Fluorescent Lamps will possibly reduce while recent lighting equipment becomes readily available without having mercury and less costly as compared to FLs. Lamps having less concentration of mercury should be used, that may also offer significant energy saving and longer life expectancy. To encourage continued innovation the policies should be developed by the industrialists to decrease the concentration of mercury in CFLs and to manufacture the lamps without having mercury or develop alternatives to mercury containing lamps. They should not send the spent fluorescent lamps to incineration facilities, instead they should be recycled. Accurate categorizing of CFLs could benefit to expand their secure accumulation and recycling and workers should be alerted to avert fracture or break of CFLs while accumulation, transportation and reusing. Collected samples of vegetable and soil from manufacturing locations indicated higher mercury concentration than those of the control sites, which means that compact fluorescent lamps manufacture procedure does truly influence release of mercury into the surrounding ambience. Besides this, if the CFL is under use, care should be taken in order to prevent its breakage and if the lamp is broken down, proper procedure has to be followed. Recycling companies or programs for CFLs must have support financially and technically, from the Government. Programs by the manufacturers could be adopted for CFLs to be returned back to their companies by the retailers after the end of the life of lamps, for recycling. Recycling programs must encourage consumers by some discount for recycling the lamp, in case the consumer returns back the CFL, which could increase the rate of recycling.