Chemical Contaminants and Pollutants in the Measurable Life of Dhaka City

Environmental pollution and food contamination are as old as the civilization itself. It is the consequence of the development of civilization, over utilization of nature, industrialization and in fact a price for the progress. It is highly prominent in Dhaka city. Air pollution is mainly due to the vehicle emission, industrial discharge and burning of fossil fuel. The water resource of Dhaka becomes a major health threat due to arsenic contamination, inadequate household/industrial/medical waste disposal and industrial effluent management. Food contamination came from the commercialism of business people who are doing this knowingly to maximize profit. Necessary steps are to be taken to protect the environment for our own existence. This paper reveals chemical pollution and contamination issues of Dhaka city, the capital of Bangladesh. Purpose of the study: Brief review of chemical induced pollution and contamination, their consequences and control. Healthcare providers/ Policy makers have a major role play to concerned field. Materials and Methods: Comprehensive literature search followed by consulting healthcare professionals about environmental pollution and food contamination. Hospital, clinic and company personnel, newspaper journalists, NGO workers given their valuable suggestions and asked help for necessary books, journal, newsletters. A few western magazine and newspapers also observed to get necessary concern. Projections were based on public life pattern, their food habits, pollution and contamination sources, waste disposal features of urban life as well as industry and hospital waste disposals. Results and Discussions: Pollution and adulteration mankind. Civilization own drawback that even causing Very few people raised on by the facts of commercialism. The scope of this article is limited to chemical pollution of air and water, medical or household waste products and food contaminants and adulterants. A few discussions based on real life experience and recent studies or reports from various journals and news articles are summarized here. Findings: Both general people and the old system, are responsible for this unlivable condition of Dhaka city. Population is not the sole for this instance. A sense of poor rules and regulation is always raised everywhere. Negligence is becoming a wide spread disease contaminating illiterate to well educated, all kind of people. Research limitations: Many articles and documents found in concerned area of research, but the scope of this research is on its focus point chemical hazards and burdens of Dhaka city. Still the most important aspect is covered, but fact is less amount of recent data found in few areas. Practical Implication: The language of this article is too simple to understand by people with simple literacy. Pharmacists, doctors, nurses, hospital authorities, public representatives, policy makers and regulatory authorities must acquire much from this article. Social Implication: Any article or research is based on the think beneficence for mankind, at least going ahead from the present situation, overcoming problems and measures. The article should create an instruction for the future policy makers of both government and other sectors to review the alarming situation of chemical pollutions and food contaminants of Dhaka, along with the whole Bangladesh. Again, world business is moving to Asian countries, Bangladesh will be an important business hub within next few decades. This article should remind policy makers that we should not forget mankind, giving places to industrialization and development.


Introduction
Contamination is the presence of an unwanted substance where it should not be or at concentrations above recommended. Pollution is contamination that results in detrimental biological effects to resident communities. All pollutants are contaminants, but not all contaminants are pollutants. All elements of the natural environment can be altered, sometimes with harmful results. Air, food, water, and the earth can all become sources of ailment, in the home, public, or work environments. In urbanization, all processes are viewed in relation to the city. Generally, better food supply, good medical care, education, jobs, industrialization, commercialization, electrification, specialization of professions, and entertainment are the basic causes of urban growth. Accessible energy plays an important role in our development with this, people can enjoy all the modern facilities [1][2][3][4].
By establishing road communication, an undeveloped area may relate to a developed area. It helps the people of the areas, the use of information, technology, and media for an improved standard of living. With increased industrialization, air, in Western, as well as developing countries, now contains toxic substances that are either direct results of combustion or produced by photochemical change. Dhaka, being the capital of Bangladesh ranked 3rd worst in Air Quality Index (AQI) in the world. Besides, the city of nearly 20 million inhabitants, Dhaka faces challenges on this front, ranging from poor sanitation, polluted rivers, and chemical outpouring from the surrounding industries, all resulting from the impromptu nature of urbanization. Food contaminants and adulterants gave a new dimension in city life, together rest of the country. The healthcare providers role in environmental health is related primarily to being alert to the conditions predominant in the community and of working with others to adequately control any of the attendant hazards [5].

Urbanization and Its Impact
Urbanization is one of 21 st century's most transformative trends. Cities are the dominant force in sustainable economic growth, development, and prosperity in both developed and developing countries. In developed countries, the growth of the urban population has stabilized, and urbanization is taking place at a rapid pace. Currently, 55% of the world's population (four billion people) reside in urban areas which will be nearly 70% by 2050 (United Nations, 2018). By 2030, over 60% people will live in the cities (Megacity Challenges, Siemens AG), two billion more people will have migrated to cities--placing unprecedented pressure on infrastructure and resources, particularly those related to water (According to UN and World Bank) [6]. From 2016 to 2030, a 35% population increase is expected in the top ten megacities.
Furthermore, as more than three-quarters (76%) of the world's mega-cities are coastal, there will be a considerable impact on water ecosystems from ridge to reef. Because of this, local and regional authorities lead initiatives targeting waterrelated obstacles, including housing gaps, climate change and an increased demand for food, energy and water [7,8]. Forecasts indicate cities in developing countries including Karachi, Lagos, and Dhaka will surpass cities like New York, Osaka, and Sao Paulo by 2030 [9]. This represents a 50% increase in demand for energy and water, generating challenges that exert pressure on water resources and threaten global water security.
This has a palpable effect on public health, economics, and development. It has been estimated that the urban population in Bangladesh will rise to between 91 and 102 million by 2050, which will be 44% of the total population [10]. The leather tanning industry has been identified as one of the main causes of environmental and water pollution in the Capital city of Dhaka of 10 million people. About 60,000 tons of row hides and skins are processed every year using dehairing, ammonium salt sulphate and chloride during de-liming, solvent vapors which releases a huge quantity of untreated effluent into the open causing air pollution and water bodies [11].

Chemical Pollution and Contamination Due to Urbanization
Smog results from the interaction of the ultraviolet rays in sunshine and the unburned hydrocarbons of automobile engines or factories and smokestacks. These products, when trapped by the thermal inversion engendered by local topography, cause damage to mucous membranes and lungs when inhaled [12]. Acute episodes of air pollution have been found to exacerbate illness and even cause death in people who already have respiratory and cardiovascular diseases. Supporting evidence exists demonstrating that second-hand tobacco smoke increases the risk of cardiovascular diseases or cancer as well [13]. According to World Bank's Country Environmental Analysis (CEA) 2018 report, air pollution lead to deaths of 46,000 people in yearly in Bangladesh [7]. Waterborne infectious disease is very common today, all the public supplies are literally contaminated with water drainage system reported many places.
Many complaints about the taste, appearance, and physical qualities of locally supplied water have led to a brisk in bottled water [14]. Water contamination with ground-source chemicals (e.g., pesticides, fertilizers) remains an ongoing possibility. Food remains a significant vehicle of disease organisms [15]. Foodborne disease more commonly but often incorrectly called "food poisoning," is grossly underreported. In most instances the illness produced by contaminated food is mild and of short duration, but more severe outbreaks (such as hepatitis A, most commonly seen in public restaurants) can. Epidemics of foodborne disease are dramatic and sudden, and most people become sick within 6 to 24 hours after consuming the contaminated foodstuffs. The epidemic pattern of food-borne disease presents differently from the gastrointestinal symptoms (e.g., nausea, vomiting, and diarrhea) induced by intestinal enteroviruses occur [16]. like uninterrupted utilities. Along with general people, the city is also heaven for muggers, robbers, thieves, pickpockets, frauds, drug dealers and organized criminals [19]. People rarely can see the sunrise or sunset due to thousands of buildings.
Hawkers are illegally occupying the public walkways, pedestrians are now forced to walk on the roads which raises the risks of accidents and adds to the already unbearable traffic congestion in those areas. Economist Intelligence Unit (EIU) The EIU surveyed 140 cities around the world for its Global Liveability Index 2018, scoring them on over 30 specified parameters under five categories: healthcare, infrastructure, culture and environment, stability, education and infrastructure (The Global Livability Index, 2018). All these things make this a difficult to breath place and a second worst place in the world to live in. Some 18,000 deaths from environmental pollution occurred in 2015 in Dhaka Environment Desk (2016).

Air Pollution
The most profound chemicals found harmful to human health and at high enough concentrations ( Table 1) can even be fatal are Carbon monoxide (CO), Sulfur dioxide (SO2), Nitrogen oxides (NOx), Ozone (O 3 ), Hydrocarbons (HC) and Suspended Particulate Matter (SPM) found in places surround Dhaka. Possible health hazards found to be headache, eye-nose-throat irritation, allergy, lung injury, trauma and even death with long term exposure [20][21][22][23][24]. The AQI in Dhaka during the winter, where more than 4,500 brick kilns operate, typically hovers above 250 -a level considered unhealthy for all groups -but often spikes much higher [25]. Brick kilns, unfit vehicles run by fuels with higher level sulphur, as well as construction works, rundown roads have been identified as major sources of air pollution [26,27]. Day by day the amount of dust include air pollution in the city has been increasing. The air quality, particularly in Dhaka has undoubtedly been getting worse. Air pollution, according to Thomson Reuters Foundation, caused largely by burning fossil fuels, is cutting global life expectancy by an average of 1.8 years per person, making it the world's top killer [28]. AQI 201 to 300 is marked as "extremely unhealthy" or hazardous air. At present AQI level of Dhaka has 309, which is in extreme "unhealthy" position [7].

Water Pollution
Moving on to the issue of water quality and pollution, the National Sustainable Development Strategy (NSDS) of Bangladesh identifies the following reasons behind degradation of surface water quality: 1.
Unregulated industrial expansion,

3.
Encroachment of rivers and water bodies,

5.
Confusion about institutional responsibility for the quality of urban water bodies, and
The Rivers Buriganga, Shtalakhka, Balu, Tongi Khal and dholeswari which runs past Dhaka City, is at present one of the most polluted rivers in Bangladesh [30]. The city is suffering from an acute lack of domestic water supply. Water is involved in the spread of contagious diseases in essentially two ways. The well-known direct ingestion of infectious agent when drinking contaminated water. The second is due to a lack of enough water for personal solitariness purposes [31]. Approximately 80% of all sicknesses and diseases can be attributed to inadequate water supply and sanitation worldwide [32,33]. However, the rivers and canals continued to be encroached upon, and more wastewater from houses and industrial units poured into the rivers without any treatment, with several major sources of pollution being outside the city area-in Ashulia, Savar, Tongi and Gazipur [34]. According to Dhaka Water Supply and Sewerage Authority (DWASA), it can currently supply 75% of water demand, out of which 85% is from groundwater sources (Deep Tube wells) [35]. The presence of toxic metal lead in Elephant road, Dhaka.University, Jatrabari, and Demra area and toxic Penta Chloro Phenol (PCP) and existing pathogenic bacterial load in the WASA supplied drinking water from different areas of Dhaka city were found to be unsuitable for human consumption [36] (Table 2). Some 80% of wastes are being dumped into the rivers in Bangladesh. No wonder our water supplies are in jeopardy. Around 250 industries are discharging chemical pollutants into the Buriganga and Sitalakhya river. Every day 4,000 tons of solid waste and 22,000 tons of tannery waste mixes with water in Buriganga river. Sewage is being discharged directly into the rivers, and the low-lying parts around urban areas [37,38]. By 2021 the garments export target has been set at $50 billion. But the success comes at a huge environmental cost.
The dyeing and finishing plants are the major pollutants of water. Turag that flows by Tongi is almost dead with pollution. Its water looks ink black and gives out such a foul smell [39].
Wetlands around Dhaka city are being destroyed through land development and dumping of toxic effluents and untreated sewage. Industrial effluents have destroyed the ecology of rivers near these large urban areas [40]. In Dhaka, 20 canals have disappeared. Liquid and solid wastes, and heavy metals like copper, iron, lead, and nickel are distressing the BOD, COD, DO, TDS, PH of water [4].

Medical and Household Solid Waste
Dhaka City Corporation (DCC) is unable to impose rules on the public. On the institutional side, rules and regulations are not clear. The role and responsibilities of waste generators are not clearly defined i.e., the present law does not provide penalties for illegal disposal of waste or littering. Lack of scientific approaches for problem solving and DCC has shortages of skilled human resources and finances [41]. The accumulating waste is dumped by the residents in the city's streets, open storm water and wastewater drains or open water bodies where and whenever the collection service is inexistent or dysfunctional [42]. Slum or periphery areas are affected by such a situation.
During the annual monsoon rains wastewater and storm water drains which are clogged by solid waste overflow, creating an acute sanitary and hygienic threat in low-lying slum areas particularly. Solid waste generation profile is Per Capita Waste Generation: 0.56 kg/cap/day, Total Waste Generation DCC Area: 5000 tons/day and 70% -80% of the solid waste is organic.

Waste Category Description with Examples
Infectious waste Pathogens may be present. E.g. excreta, laboratory cultures, tissues, materials or equipment that have been in contact with infected patient.

Pathological waste
Human tissues or fluids. E.g. blood and other body fluids, fetuses.
Pharmaceutical waste Wastes containing pharmaceuticals. E.g. pharmaceuticals that are no longer needed or expired Genotoxic waste Waste containing substances with genotoxic properties. e.g. waste containing cytotoxic drugs (often used in cancer therapy); genotoxic chemicals.

Chemical waste
Chemical substances present in a waste. E.g. laboratory reagents, film developer; disinfectants that are expired or no longer needed; solvent.
Wastes with high content of heavy metals Batteries, broken thermometers, blood-pressure gauges.

Pressurized containers Gas cylinders, aerosol cans
Radioactive waste Radioactive substances present in a waste. e.g. unused liquids from radiotherapy or laboratory research, contaminate glassware, packages or absorbent paper.
Medical waste may contain highly toxic chemicals and can present a mechanism for transmission of diseases ( Table 3). The growth of the medical sector around the world over the last decade combined with an increase in the use of disposable cheap medical products has contributed to the large amount of medical waste being generated. For a megacity like Dhaka, even low hazardous wastes generation rates can lead to the accumulation of large quantity wastes [43]. This enormous amount of medical waste poses from different healthcare establishment (HCE) ( Table 4) significant health risks to the people associated with waste disposal and treatment. During monsoon, the situation gets worse as medical, toxic chemicals and sewage waste flood Dhaka streets, contaminating dozens of neighborhoods in the process. The reuse of syringes by the general public represents one of the greatest public health problems in the developing world related to health care waste. Worldwide, an estimated 10 to 20 million infections of Hepatitis B and C and HIV occur annually from the reuse of discarded syringe needles without prior sterilization [44].

Food Contamination
Dhaka city now alone generates huge solid wastes per day from industrial discharge, fertilizers, fossil fuels, sewage sludge and municipality wastes and they are the major sources of heavy metals in soils and subsequent uptake by crops, vegetables and other food items causing serious health hazards to human beings [45,46]. A significant transfer of heavy metals like arsenic, cadmium, chromium, copper, lead, mercury, nickel, zinc, molybdenum and vanadium took place from soils to vegetables (spinach, tomato and cauliflower) grown in industrially polluted soils of Konabari at Gazipur and Keraniganj in Dhaka [47]. Industrial wastes and effluents are being discharged randomly on soils, into canals, rivers, along the road sides or in the vicinity of the industrial areas without any treatment where polluted river water is being used for irrigation purpose in paddy and vegetable cultivation causing absorption of heavy metals through the food chain by human beings [48].

Food Adulterants
Important food hazards include microbial hazards, pesticide residues, misuse of additives, chemical contaminants, including biological toxins and adulteration. Although microbiological contamination and chemical hazards have received most attention, it is recognized that food adulteration and food fraud should not be neglected considering their role in public health (FAO/WHO Expert Consultation, 1986). Food adulteration includes various forms of practices, such as mixing, substituting, concealing the quality of food by mis-labelling, putting up decomposed or expired food, and adding toxic substances [49]. About the proportion of adulterated food items in the market varied between 70% to 90%. Nearly 80% food items in the market were found contaminated in a random survey by public health laboratory of Dhaka City Corporation in 2004 [50,51].
According to the International Centre for Diarrheal Disease & Research, Bangladesh [52,53], there is approximately 150 food items in the country. A study by the Institute of Public Health (IPH) revealed that more than 50% of the food samples they tested were adulterated. Textile dyes, which are highly injurious to health, are being randomly used to color many types of food. Fish is an essential protein for people of all ages. Many fish sellers spray fish with formalin in an assorted manner, it makes the fish or fruits stiff and keeps them looking fresh for longer. Undoubtedly human health is now under the possession of formalin, in our country about 400 tons formalin is being imported which are goes to human stomach, even though for laboratory or research purposes 100 tons of Formalin is quite enough, 80% of the imported formalin being added to food only for business purposes [54][55][56][57][58][59][60] (Table 5). Milk in rural areas is usually devaluated with dirty water, which can cause hepatitis. People are now acquainted with the milk adulteration technique that uses a thickening agent, sorbitol, and detergent. ICDDR, B recent studies shows nearly 75% samples from primary-level producers were contaminated with coliform and more than 50% with fecal coliform bacteria. At the collection points, samples were found contaminated with a high number of coliform bacteria and fecal contamination of more than 90% while more than 40 % of the samples had a high E coli count [52].
Vegetable and fruit samples collected from around Savar, Dhamrai and Tongi show the presence of textile dyes, which, in the short-term, will cause diarrhea, food poisoning and gastrointestinal problems, but in the long-term toxic materials will accumulate in the body with serious health implications.
In the absence of effluent treatment plants (ETP), the factory wastes are depleted out at will into the farmlands, and ultimately contaminate the farm produce [61]. In Bangladesh, people allowed things like pollution and food contamination to run riot.
Till now, neither under the health ministry nor the ministry of science and technology or the ministry of industries, has conducted any examination of the pesticide-residue levels or toxic chemicals in the foodstuff being marketed. These merchants and traders are the enemy not only of the nation and their own children but of the entire mankind. The holy Prophet (PBUH) has disowned those who indulge in this immoral business. He said '' The adulterator is not one of us'' [58]. Apart from these severe noxious pathogens found in different food samples (Table 6), that are potential causes of stomach problems.  Total coliforms and fecal coliforms count (CFU/g) [62]. It is an unfortunate reality that adulteration, especially in food, has become ubiquitous in the society. No one can justify or defend it. Most food products available in the market are adulterated. The average family is eating dangerous colors, chemicals like formalin and carbide, sawdust, soapstone, harmful chemicals and other harmful substances mixed with consumable goods. High level of pesticides content is present in grains, pulses, in fruits and vegetables that we eat [63]. Fecal bacteria found in 97% bottled water [55].
Brick dust in chili-powder, colored chalk powder in turmeric, injectable dyes in watermelon, peas, capsicum, brinjal, papaya seeds in black pepper etc. are frequently used [58]. Even more unfortunate is the fact that this nefarious practice increases exponentially during the month of Ramadan. The shopkeepers and the merchants-many of them with a pious façade-try to earn a large amount of profit by this unethical practice, and so they play with the life and health of the people [64,65]. They mix dangerous things in the daily eatables. Even the medicine and drugs are adulterated. Most people can't even think of having the commodities like ghee, oil, salt and milk, free from impurities [66][67][68][69][70].

Recommendations
Pollution and contaminant control are a never ending, on the other hand a continuous process. It will increase with time as the civilization go ahead. Pharmacists should be aware of the local occupations, companies, and factories and to be cognizant of the initial symptoms of disease. Again, pharmacists should become acquainted with the local community and to adapt the principles of health and medical care to the situations encountered. The pharmacist's continuing education requirements should include watching the local pattern of society and its diseases and changing the emphasis toward evolving disease patterns and their control.
Included in the current environmental issues are the workplace and the future of occupational safety and health regulations, hazards of local ambient environments, such as hazardous and other waste dumps, radioactive waste from weapons production, air emissions, and groundwater contamination of unknown magnitude; the Clean Air act and other and regulatory initiatives; waste reduction and minimization, and radioactive waste and weapons production; global pollution, chlorofluorocarbons and the land ozone layer, the greenhouse effect, and global climate change; and conserving the tropical forest and biological diversity. Government and regulatory authorities are to play strong role in controlling food contaminants and adulteration. An out of the box thinking is decentralization i.e. to move few many important originations away from Dhaka city. With this decentralization, population density will be declined, the ill movement of business Crips will also be diluted.

Conclusion
With constant change to the physical, biological, cultural, social, and economic environment, both pharmacists and citizens should cultivate an informed awareness of these changes, and health providers should adapt their methods of health education, disease prevention, and disease control to the changes in each community. With an unusually large number of people seeking relief from health hazards, providers may play a much more fundamental and personal role in controlling foodborne diseases. The necessary role in environmental health is related primarily to being alert to the conditions prevailing in the community and of working with others to adequately control any of the attendant hazards.