Microorganisms have a variety of essential functions within the environment such as aid in the natural process of recycling living matter. Common types of microorganisms include bacteria, fungi, protozoa and viruses. All substances which are produced naturally are essentially described as biodegradable, which means that microorganisms can break them down. Microorganisms can either be quite useful, or terribly destructive to human organisms. There is a preconceived notion to most that all bacteria and viruses can make us sick, and that some can even lead to fatalities, but not all are bad for us. For instance, in our intestines, there are bacteria and viruses that help to digest food and create inhospitable conditions to prevent more dangerous microorganisms from inhabiting the body via that region. Most times we can often find that we get sick not very long after being treated with antibiotics since these medications would have destroyed much of the useful bacteria in our intestines. This makes it easier for the dangerous microorganisms to attack and spread faster throughout the body infecting us. Having as wide variety of microorganisms in our bodies can actually help to strengthen our immune systems, aboard toxins and aid in reducing feelings of stress. To have an efficient ecosystem, there has to have a huge variety of microorganisms within a continuous cycle, working together. Some of the key roles microorganisms play in the ecological cycle are in decomposition, oxygen production, symbiotic relationships and evolution. Nutrients such as carbon, nitrogen, and sulfur are continuously recycled by these organisms completed by their ceaseless labor.
The carbon contained in the tissues of organisms becomes unavailable for most other living things when they die. Decomposition is the process by which these organisms are broken down by bacteria and the nutrients are released back into the environment.
For their proper health and growth, plants rely on obtaining nitrogen from the soil since they cannot acquire it from the gaseous nitrogen in the atmosphere. The main way in which nitrogen is made available to them is by means of a process called nitrogen fixation. Bacteria such as Rhizobium, and cyanobacteria such as Anabaena, Nostoc, and Spirulina, metabolizes to convert gaseous nitrogen into nitrates or nitrites to be released into the environment . Nitrogen gas or nitrous oxide is formed when denitrifying bacteria metabolized in reverse using nitrates. If those type of bacteria is allowed to colonize, it can deplete nutrients from the soil causing the land to become infertile.
Overexposure to chemicals in our environment is an occurrence humans and animals have had to face for a long time to now. Natural products in foods, smoke from cooking fires, sewage in drinking water, pesticides from plants are all sources of exposure. Industrialization h has significantly increased this risk of exposure dramatically over the last few centuries. An environmental health risk assessment is used to identify all potential hazards to human health and helps us understand how serious such problems can become. It is comprised of four components: exposure assessment; hazard identification; dose/response assessment; and risk characterization. Risk assessment is the scientific basis for standard setting. Environmental health threats may come from physical agents such as biologicals, such as mold, insects, bacteria, and viruses, as well as chemicals, ionizing agents or UV. Common environmental chemical pollutants include pesticides and herbicides, volatile organics, heavy metals, air contaminants and persistent organic pollutants. However, by using biomarkers of exposure and effect, as well as studies from some unfortunate poisoning episodes, we do have human information on many types of environmental exposures.
Elevated levels of fluoride in drinking water have been identified in numerous countries around the world. Waters high in fluoride tend to be found in discrete areas, mostly in sodium-, potassium- and chloride-rich and calcium-poor ground waters in many basement aquifers. Fluorides in small quantities aids in the protection against dental caries. However, excessive intake could result in adverse health effects such a dental fluorosis, even skeletal fluorosis and hip fractures among the elderly.
Drinking water is usually the main source of fluoride where levels are not based so much on acute toxicity effects, but rather on long-term consumption of high amounts of fluoride. Fluoride is a chemical compound which is quite difficult to eliminate from water. Membrane techniques, including reverse osmosis, nanofiltration, dialysis and electro-dialysis; and the adsorption technique are two categories of methods used to remove fluoride in water. Membrane techniques such as reverse osmosis filtration and activated alumina defluoridation are the two widely used methods.
Chlorination has long been a method used for disinfection to aid in the removal of pathogenic microorganisms from drinking water which leads to the formation of chlorinated byproducts such as trihalomethanes (THMs) and haloacetic acids (HAAs) when chlorine reacts with natural organic matter (NOM). These products have adverse health effects on human beings and are considered potentially carcinogenic water. The physical and chemical characteristics of NOM is important in determining which water treatment processes can be employed.
Living organisms react in several ways to arsenic exposure, where effects depend on the chemical form of the arsenic, the nature of the surrounding environment and the particular biological sensitivity of the organisms. Some of the adverse effects include death, poor growth and failure to reproduce. Arsenic compounds can cause short-term and long-term effects on individual plants and animals or even on populations and communities of organisms. The effects include death, inhibition of growth, photosynthesis and reproduction, as well as behavioral effects.
Nitrate is described as one of the most commonly existent groundwater contaminants in rural areas. It has to be regulated in drinking water because excessive levels consumed can cause methemoglobinemia, or ‘blue baby’ disease which has infants at the highest risk of affect. Although the possible presence of other more serious residential or agricultural contaminants, such as bacteria or pesticides can harm older children and adults.
Nitrate in groundwater commonly originates from fertilizers, septic systems, and manure storage or spreading operations. Fertilizer nitrogen that is not taken up by plants, volatilized, or carried away by surface runoff leaches into groundwater in the form of nitrate, elevating the concentration above the acceptable levels for drinking water quality. Septic systems can also increase groundwater nitrate concentrations because only about half of the nitrogen is removed in wastewater treatment, leaving the remaining half to percolate to groundwater.
The best solution is to find an alternative water supply for drinking and cooking water purposes.
With home treatment systems, a properly operating distillation system should be able to effectively remove nitrate, on the downside it is expensive to install and operate and always has to be properly adjusted. Reverse-osmosis units are another method, but as with the distillation system they are quite expensive to install and operate. Anion-exchange units are relatively inexpensive options, but on the downside they are effective for only a short period of time, that is until the unit becomes saturated and requires recharging.
Natural sources of iron and manganese are more commonly found in deeper wells where the water has been in contact with rock for a longer period of time. Iron and manganese are often found together in groundwater however manganese usually occurs in much lower concentrations than iron.
Iron and manganese are readily prevalent in drinking water supplies and tends to impart a strong metallic taste to the water and also causes staining. Iron and manganese can be removed from water using a variety of treatment processes which is ultimately dependent on both the form and concentration of the metals present. Since iron and manganese must be removed from all water entering the home using Point-of-Entry (POE) treatment devices to treat aesthetic problems.
Conventional water softeners are at times suggested for removing iron and small amounts of manganese, however, is more commonly used to remove calcium and magnesium hardness in water by an exchange process. Other common removal methods include Polyphosphate addition, Oxidizing Filters and Oxidation followed by Filtration.
Microscopically small organisms that are unicellular and some of which form colonies and can reach sizes visible to the naked eye as minute green particles are referred to as algae. Cyanobacteria are organisms that are similar to algae in size and, unlike other bacteria, they contain blue-green and green pigments and can also perform photosynthesis. Human activities have led to eutrophication of many water bodies causing an excessive production of algae and cyanobacteria in fresh water and thus considerably impacting recreational water quality.
Providing adequate information to the public on the cyanobacterial risk associated with using a particular recreational water area is important not only for avoiding this hazard, but also for understanding symptoms potentially caused by exposure and identifying their cause.
Contaminated drinking-water supplies is a known to be a significant source of outbreaks for campylobacteriosis. Control measures that can be applied to manage the possible risk from Campylobacter include protecting raw water supplies from animal and human waste, efficient water treatment and protection of water during distribution. Campylobacter are faecally borne pathogens which are particularly resistant to disinfection, which makes E. coli an appropriate indicator for the presence/absence of Campylobacter in drinking-water supplies.
Devices such as cooling towers, hot water systems and spas which makes use of mains water have been associated with outbreaks of infection caused by Legionella. Control measures should be employed to reduce the likelihood of survival and multiplication of Legionella such as disinfection strategies designed to minimize biofilm growth and temperature control can minimize the potential risk. Systems that are kept clean and flowing are less likely to support excess growth of Legionella.
Legionella are commonly found in natural flora of many freshwater environments, such as rivers, streams and impoundments and occur in relatively low amounts. Legionella are considered potentially pathogenic for humans and is responsible for legionellosis, of which are represented in two clinical forms are known as Legionnaires’ disease and Pontiac fever.
Cryptosporidium parvum, found all over the world and Giardia lamblia are two common protozoan parasites which are the leading causes of many waterborne illnesses such as Cryptosporidiosis and Giardiasis. These parasites are not effectively controlled by chlorination or other disinfectants. Water filtration is the current practice for controlling them by means of properly functioning conventional filters in collaboration with effective pretreatment of the water. After which, disinfection is finally required to remove the infectious life stages of these organisms.
The best solution for reducing the impact of all of these contaminants is by firstly creating public awareness. The public deserves the right to knowledge that can save their lives.