Question

Understanding Environmental Health in Totality

Now that you have understood the impact of environmental factors on human health, create a 7- to 10- page Microsoft Word document addressing the following questions:

• Describe three waterborne diseases and suggest methods for their prevention.
• Provide one example of a toxic chemical that may enter the public water supply? Describe some of the health effects that are attributed to toxic chemicals present in drinking water.
• What health hazards are associated with uncontrolled and older waste sites in the United States? Describe the processes through which hazardous solid wastes can affect human beings.
• Compare and contrast the current methods for treating sewage from those that were used in the Middle Ages? Historically speaking, what factors spurred the development of today's sanitary sewage systems?
• Describe the stages for processing sewage. At what stage of processing is it permissible in the United States to dispose of wastewater from sewage into waterways?
• What health-related considerations relate to the use of recycled water? What level of processing is required for wastewater to be recycled? Describe some of the uses of recycled water.
• Even though workers in professional occupations usually are not exposed directly to hazardous agents, they are prone to occupationally associated illnesses. What types of hazards and associated illnesses predominate in professional occupations? What interventions would you propose to mitigate these hazards?

Answer 1

Answer

• Describe three waterborne diseases and suggest methods for their prevention.

1. Giardiasis:  

To prevent and control infection with the Giardia parasite, it is important to:

• Practice good hygiene
• Avoid water (drinking or recreational) that may be contaminated
• Avoid eating food that may be contaminated
• Prevent contact and contamination with feces (poop) during sex

2 Amoebiasis

Prevention of amoebiasis is by improved sanitation, including separating food and water from faeces.

3.Cyclosporiasis

Prevention and control

Wash: Wash hands with soap and warm water before and after handling or preparing fruits and vegetables. Wash cutting boards, dishes, utensils, and counter tops with soap and hot water between the preparation of raw meat, poultry, and seafood products and the preparation of fruits and vegetables that will not be cooked.

Prepare: Wash all fruits and vegetables thoroughly under running water before eating, cutting, or cooking. Fruits and vegetables that are labeled “prewashed” do not need to be washed again at home. Scrub firm fruits and vegetables, such as melons and cucumbers, with a clean produce brush. Cut away any damaged or bruised areas on fruits and vegetables before preparing and eating.

Store: Refrigerate cut, peeled, or cooked fruits and vegetables as soon as possible, or within 2 hours. Store fruits and vegetables away from raw meat, poultry, and seafood.

Provide one example of a toxic chemical that may enter the public water supply? Describe some of the health effects that are attributed to toxic chemicals present in drinking water.

• Heavy metals can leach into drinking water from household plumbing and service lines, mining operations, petroleum refineries, electronics manufacturers, municipal waste disposal, cement plants, and natural mineral deposits. Heavy metals include: arsenic, antimony, cadmium, chromium, copper, lead, selenium and many more. Heavy metals can contaminate private wells through groundwater movement and surface water seepage adn run-off. People that consume high levels of heavy metals risk acute and chronic toxicity, liver, kidney, and intestinal damage, anemia, and cancer.

• What health hazards are associated with uncontrolled and older waste sites in the United States? Describe the processes through which hazardous solid wastes can affect human beings.

The sites in USA

Uncontrolled disposal sites containing hazardous waste and other contaminants have created national environmental problems (1). Because of potential health problems associated with the more than 33,000 hazardous-waste sites in the United States, the Agency for Toxic Substances and Disease Registry (ATSDR)--as part of its federally legislated mandate--has developed a list of seven priority health conditions (PHCs)* to 1) assist in evaluating potential health risks to persons living near these sites and 2) determine program and applied human health research activities involving hazardous substances identified at the sites. This report summarizes the development and intended applications of the seven PHCs.

ATSDR was created by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (as amended by the Superfund Amendments and Reauthorization Act of 1986). The mission of ATSDR is to prevent or mitigate adverse human health effects and diminished quality of life resulting from exposure to hazardous substances in the environment (2). Therefore, ATSDR has initiated medical-evaluation efforts and programs to address site- and substance-specific information needs. These programs include conducting public health assessments of individual hazardous-waste sites and health studies and establishing public health surveillance systems and registries of persons exposed to hazardous substances.

Since 1986, ATSDR has conducted public health assessments for more than 1200 of the nearly 1300 sites identified on the Environmental Protection Agency's National Priorities List (NPL) and has conducted more than 85 health-study activities. In addition, ATSDR has evaluated the chemicals that pose the greatest human health hazards at NPL sites; the list of 275 hazardous substances was based on 1) the frequency with which a chemical was found at NPL sites, 2) the chemical's toxicity, and 3) the likelihood of human exposure to the chemical.

ATSDR used information derived from health studies, public health assessments, and toxicologic profiles to develop a list of seven PHCs--birth defects and reproductive disorders, cancers (selected sites), immune function disorders, kidney dysfunction, liver dysfunction, lung and respiratory diseases, and neurotoxic disorders.

• Compare and contrast the current methods for treating sewage from those that were used in the Middle Ages? Historically speaking, what factors spurred the development of today's sanitary sewage systems?

Chemicals can enter the environment from many different sources such as landfills, incinerators, tanks, drums, or factories. Human exposure to hazardous chemicals can occur at the source or the chemical could move to a place where people can come into contact with it. Chemicals can move through air, soil, and water. They can also be on plants or animals, and can get into the air we breathe, the food we eat and the water we drink.

Sweeping progress has been made since the enactment of the Clean Water Act (CWA) in 1972. Led by the growing public concern about controlling water pollution, the CWA has resulted in strict wastewater standards for industry. It established the basic structure for regulating pollutant discharges into U.S. waters and funded the establishment of sewage treatment plants under the construction grants program.
Wastewater treatment is and always has been essential to human health by preventing the spread of deadly diseases and protecting the environment. Even centuries ago, people were coming up with rather ingenious ways to get rid of waste.

I recently came across a very unique article in BBC News Magazine. It revealed contents of a rare medieval document, the Assize of Nuisance, which discussed some mind-blowing toilet inventions and waste management techniques from some 700 years ago in 14th-century London.

According to the document, a 700-year-old toilet was nothing more than a hole cut in a wooden platform over a cesspool. (Odor control not available.)

The document reveals that a forward-thinking Londoner, who perhaps was unhappy with the functionality of the wooden platform toilet, built a toilet in her own residence. She engineered a wooden pipe that connected her toilet to a rainwater gutter that flushed a nearby public latrine. While extraordinarily inventive, the citizen was ordered by city authorities to remove the pipe because the solids from her toilet blocked the gutter and the stench greatly inconvenienced neighbors.

Obviously, medieval cities lacked infrastructure that dealt with the disposal of human waste. Instead, waste was simply dumped into rivers or buried in the ground. And although there were rules forbidding the disposal of filth outside people’s homes, according to the article, these rules were mostly ignored.

However, when the bubonic plague spread like wildfire across London in the late 1340s, city officials passed stricter laws to clean up the waterways, forbidding waste dumping into the Thames and other water bodies.
The article also mentions some rather amusing professions added to the city payroll, including: muckrakers, the first street cleaners, who collected filth and took it outside the city walls; surveyor of the pavement, the first bin men; and gong farmers, who cleared out cesspits, latrines and privies.

Needless to say, a lot has changed in waste management since medieval times, and not just in the form of regulations and standards. Advances in wastewater collection and treatment technologies have not only made a difference in water quality and environmental protection, but also have helped tackle water scarcity through effective reuse and recycling practices. Both energy-smart and alternative technologies have reduced facilities’ carbon footprint and operating expenses.

Only time will tell how far technology development will go just in the next decade alone, not to mention centries from now. One thing is certain—wastewater treatment will forever have a large impact on society.

One of the most common forms of pollution control in the United States is wastewater treatment. The country has a vast system of collection sewers, pumping stations, and treatment plants. Sewers collect the wastewater from homes, businesses, and many industries, and deliver it to plants for treatment. Most treatment plants were built to clean wastewater for discharge into streams or other receiving waters, or for reuse. Years ago, when sewage was dumped into waterways, a natural process of purification began. First, the sheer volume of clean water in the stream diluted wastes. Bacteria and other small organisms in the water consumed the sewage and other organic matter, turning it into new bacterial cells; carbon dioxide and other products. Today’s higher populations and greater volume of domestic and industrial wastewater require that communities give nature a helping hand. The basic function of wastewater treatment is to speed up the natural processes by which water is purified. There are two basic stages in the treatment of wastes, primary and secondary, which are outlined here. In the primary stage, solids are allowed to settle and removed from wastewater. The secondary stage uses biological processes to further purify wastewater. Sometimes, these stages are combined into one operation. Primary Treatment As sewage enters a plant for treatment, it flows through a screen, which removes large floating objects such as rags and sticks that might clog pipes or damage equipment. After sewage has been screened, it passes into a grit chamber, where cinders, sand, and small stones settle to the bottom. A grit chamber is particularly important in communities with combined sewer systems where sand or gravel may wash into sewers along with storm water. After screening is completed and grit has been removed, sewage still contains organic and inorganic matter along with other suspended solids. I These solids are minute particles that can be removed from sewage in a sedimentation tank. When the speed of the flow through one of these tanks is reduced, the suspended solids will gradually sink to the bottom, where they form a mass of solids called raw primary biosolids formerly sludge). Biosolids are usually removed from tanks by pumping, after which it may be further treated for use as a fertilizer, or disposed of in a land fill or incinerated. Over the years, primary treatment alone has been unable to meet many communities’ demands for higher water quality. To meet them, cities and industries normally treat to a secondary treatment level, and in some cases, also use advanced treatment to remove nutrients and other contaminants. Secondary Treatment The secondary stage of treatment removes about 85 percent of the organic matter in sewage by making use of the bacteria in it. The principal secondary treatment techniques used in secondary treatment are the trickling filter and the activated sludge process. After effluent leaves the sedimentation tank in the primary stage it flows or is pumped to a facility using one or the other of these processes. A trickling filter is simply a bed of stones from three to six feet deep through which sewage passes. SECONDARY TREATMENT Activated Biosolids Process More recently, interlocking pieces of corrugated plastic or other synthetic media have also been used in trickling beds. Bacteria gather and multiply on these stones until they can consume most of the organic matter. The cleaner water trickles out through pipes for further treatment. From a trickling filter, the partially treated sewage flows to another sedimentation tank to remove excess bacteria. The trend today is towards the use of the activated sludge process instead of trickling filters. The activated sludge process speeds up the work of the bacteria by bringing air and sludge heavily laden with bacteria into close contact with sewage. After the sewage leaves the settling tank in the primary stage, it is pumped into an aeration tank, where it is mixed with air and sludge loaded with bacteria and allowed to remain for several hours. During this time, the bacteria break down the organic matter into harmless by-products. The sludge, now activated with additional billions of bacteria and other tiny organisms, can be used again by returning it to the aeration tank for mixing with air and new sewage. From the aeration tank, the partially treated sewage flows to another sedimentation tank for removal of excess bacteria. To complete secondary treatment, effluent from the sedimentation tank is usually disinfected with chlorine before being discharged into receiving waters. Chlorine is fed into the water to kill pathogenic bacteria, and to reduce odor. Done properly, chlorination will kill more than 99 percent of the harmful bacteria in an effluent. Some municipalities now manufacture chlorine solution on site to avoid transporting and storing large amounts of chlorine, sometimes in a gaseous form. Many states now require the removal of excess chlorine before discharge to surface waters by a process called dechlorination. Alternatives to chlorine disinfection, such as ultraviolet light or ozone, are also being used in situations where chlorine in treated sewage effluents may be harmful to fish and other aquatic life.

Key potential health risks

Microbial pathogens in wastewater from sewage effluent are the major concern for human health when recycling water. The major groups of pathogens are:

• Bacteria (e.g. Escherichia coli, Salmonella spp)
• Viruses (e.g. Enteroviruses, Rotavirus, Hepatitis A)
• Protozoa (e.g. Giardia Lamblia, Cryptosporidium parvum)
• Helminths (e.g. Taenia spp (Tapeworm), Ancylostoma spp (Hookworm))

Not all infections make you sick. To become infected by a pathogen you must be exposed to a sufficient number of pathogens. If recycled water is fit for the intended purpose, exposure will be low and infection unlikely as it is related to the concentrations of pathogens in the recycled water and the amount of water ingested.

• What health-related considerations relate to the use of recycled water? What level of processing is required for wastewater to be recycled? Describe some of the uses of recycled water.

Key potential environmental risks

Some of the common environmental risks from recycled water include:

Salinity

A chronic problem which needs to be managed in all irrigation systems. Can result in reduced plant growth and plant damage and can impact on freshwater plants and invertebrates in natural ecosystems if discharged directly with little dilution. Most common salts are sodium chloride

Sodicity

Excess sodium in recycled water can cause soil dispersion/swelling, reducing water infi ltration on heavier textured soils. This can be difficult to remedy.

Sodium

Can be toxic to some plants if it accumulates in soils from ongoing irrigation. More important as a omponent of salinity and sodicity.

Chloride

Can be toxic to plants if sprayed directly on leaves, and if it accumulates in soils from ongoing irrigation, but is usually more important as a component of salinity.

Nitrogen

Mostly of benefit to cultivated plants, but can cause eutrophication (excessive nutrient levels) in land and aquatic ecosystems.

Phosphorus

Mostly of benefit to cultivated plants, but can cause eutrophication (excessive nutrient levels) in land and aquatic ecosystems.

Chlorine residuals

By-products of disinfection processes may be harmful to aquatic or marine ecosystems if discharged directly with little dilution.

Hydraulic loading

Too much water applied to land can result in excess groundwater recharge, water logging and secondary salinity.

Boron

Plant toxicity may arise in some plants in some soils if it accumulates from ongoing irrigation.

Surfactants

Some organic and inorganic surface active agents from detergents can remain in recycled water and be harmful to some aquatic organisms.

Other risks which require monitoring

A broad range of chemicals have been identified as having the potential to alter normal endocrine function in animals, i.e. endocrine disrupting chemicals (EDCs). At this stage, there is no evidence that environmental exposure to low levels of potential EDCs (potentially present in recycled water) affects human health because of the relatively low exposure.

However, ongoing monitoring is required to ensure good risk management. Pharmaceutical chemicals and their metabolites, potentially found in recycled water, raise similar issues to EDCs (above). Health impacts from pharmaceuticals should also be minimal because of the relatively low exposure. However, ongoing monitoring is required to ensure good risk management.

Recycle water can be use for

• Flushing toilets
• Watering plants and vegetables in your garden
• Watering the lawn
• Washing cars (on the lawn only)
• Cleaning the outside of your home and outdoor furniture
• Fighting fires

• Even though workers in professional occupations usually are not exposed directly to hazardous agents, they are prone to occupationally associated illnesses. What types of hazards and associated illnesses predominate in professional occupations? What interventions would you propose to mitigate these hazards?

Asbestos

Although the import, supply and use of all forms of asbestos has been banned for a long time, a high number of tradespeople are still at risk from exposure to asbestos. Any building built before the year 2000, both residential and industrial, may still contain asbestos-containing materials that could be disturbed by tradespeople carrying out work.

Exposure to asbestos is associated with the following diseases: mesothelioma, lung, larynx and stomach cancers, as well as asbestosis and pleural thickening, resulting in around 5000 deaths each year. Many of these deaths are due to past exposure to asbestos; however, asbestos is still a risk today.

The following initiatives have been developed to raise awareness of the dangers of asbestos amongst tradespeople:

• HSE’s Beware Asbestos campaign launched in October 2014. The campaign aims to raise awareness and help tradespeople protect themselves from the dangers of asbestos. The campaign includes some useful reference cards and a FREE Beware Asbestos Web app that can help tradespeople to identify if asbestos is likely to be in their workplace. It gives them practical advice on how to protect themselves from the dangers, and advises them on when and how to get experts involved.
• For further information on occupational diseases, and other initiatives please register on the Occupational Disease community site.