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Contaminants of emerging concern (CECs) is a term used by water quality professionals to describe pollutants that have been detected in environmental monitoring samples, that may cause ecological or human health impacts, and typically are not regulated under current environmental laws. Sources of these pollutants include agriculture, urban runoff and ordinary household products (such as soaps and disinfectants) and pharmaceuticals that are disposed to sewage treatment plants and subsequently discharged to surface waters. [1] [2]
CECs include different substances like pharmaceuticals, personal care products, industrial byproducts, and agricultural chemicals. These substances often bypass regular detection and treatment processes, leading to their unintended persistence in the environment. The complexity of CECs arises not only from their different chemical nature but also from the complex ways they interact with ecosystems and human health. As such, they are the focus of increasing examination by researchers, policymakers, and public health officials who want to understand their long-term effects and develop effective interventions. Global initiatives, like the World Health Organization (WHO) and the Environmental Protection Agency (EPA), emphasize the need to create international standards and effective environmental policies to address the challenges posed by CECs. Public awareness and advocacy play crucial roles in driving the research agenda and policy development for CECs, highlighting the need for updated manufacturing practices and developing more remediation and detection methods.
The concept of CECs gained significant attention in the early 21st century as advances in analytical techniques allowed for the detection of these substances at trace levels in various environmental matrices. The increased awareness of CECs is partly due to their abundant presence in wastewater, surface water, groundwater, and drinking water, often because of urbanization, industrial activities, and the widespread use of pharmaceuticals and personal care products. [3] The recognition of the potential risks posed by CECs has led to a growing body of research aimed at understanding their sources, fate, and effects in the environment, as well as the development of strategies for their management and removal. [4]
For a compound to be recognized as an emerging contaminant it has to meet at least two requirements: [12]
Emerging contaminants are those which have not previously been detected through water quality analysis, or have been found in small concentrations with uncertainty as to their effects. The risk they pose to human or environmental health is not fully understood. [12]
Contaminants of emerging concern (CECs) can be broadly classed into several categories of chemicals such as pharmaceuticals and personal care products, cyanotoxins, nanoparticles, and flame retardants, among others. [13] However, these classifications are constantly changing as new contaminants (or effects) are discovered and emerging contaminants from past years become less of a priority. These contaminants can generally be categorized as truly "new" contaminants that have only recently been discovered and researched, contaminants that were known about but their environmental effects were not fully understood, or "old" contaminants that have new information arising regarding their risks. [13]
Pharmaceuticals are gaining more attention as CECs because of their continual introduction into the environment and their general lack of regulation. [14] These compounds are often present at low concentrations in water bodies and little is currently known about their environmental and health effects from chronic exposure; pharmaceuticals are only now becoming a focus in toxicology due to improved analytical techniques that allow very low concentrations to be detected. [14] There are several sources of pharmaceuticals in the environment, including most prominently effluent from sewage treatment plants, aquaculture and agricultural runoff. [15]
Personal care products often contain a complex mixture of chemicals such as preservatives (e.g., parabens), UV filters (e.g., oxybenzone), plasticizers (e.g., phthalates), antimicrobials (e.g., triclosan), fragrances, and colorants. [16] Many of these compounds are synthesized chemicals that are not typically found in nature. Chemicals from personal care products can enter the environment through various pathways. After use, they are often washed down the drain and can end up in the wastewater stream. These substances are not all completely removed by conventional wastewater treatment processes, leading to their release into natural water bodies. Some of these chemicals are persistent in the environment and can bioaccumulate in the tissues of organisms, potentially causing ecological disruptions. They can also have endocrine-disrupting properties that interfere with the hormonal systems of wildlife and humans. [17]
In recent years, there has been an increase of cyanobacterial blooms due to the eutrophication (or increase in nutrient levels) of surface waters around the world. [18] Increases in certain nutrients, such as nitrogen and phosphorus, are linked to fertilizer runoff from agricultural fields, and are also found in certain products, such as detergents, in urban spaces. [19] These blooms can release toxins that can decrease water quality and are a risk to human and wildlife health. [18] Additionally, there are a lack of regulations regarding the maximum contaminant levels (MCL) allowed in drinking water sources. [19] Cyanotoxins can have both acute and chronic toxic effects, and there are often many consequences for the health of the environment where these blooms occur. [19]
Industrial chemicals from various industries produce harmful chemicals that are known to cause harm to human health and the environment. Common industrial chemicals, like 1,4-Dioxanes, Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA), are commonly found in various water sources.
Nanomaterials include carbon-based materials, metal oxides, metals, and quantum dots. [20] Nanomaterials can enter the environment during their manufacturing, consumer use, or disposal. Due to their small size, nanomaterials behave differently than larger particles. [21] They have a high surface area to volume ratio, which can lead to increased reactivity and the potential to transport throughout the environment. Nanomaterials are challenging to detect and monitor due to their size and the absence of standardized methods for measuring their presence and concentration in various media. [22]
Agricultural runoff is a major pathway through which CECs enter the environment. [23] Compounds like pesticides and pharmaceuticals from fertilizers are carried by water from farms into their surrounding areas soil and water bodies. [24] Then runoff happens after rainfall or irrigation, which causes an influx of chemicals to leak out of the soil where they were dumped and into rivers, lakes, and groundwater. [24] The runoff can contain a CEC’s which are not regulated or whose environmental impacts are not well understood, [12] contributing to the pollution of aquatic ecosystems, and potentially affecting human water sources. A significant challenge is monitoring levels of CECs in bodies of water. A nationwide survey revealed that soil erosion, nutrient loss, and pesticide runoff from America's vast agricultural lands are leading causes of water quality pollution. Approximately 46% of rivers and streams in the United States have conditions which are harmful to aquatic life. Additionally, only about 28% of these water bodies are rated as 'healthy' based on their biological communities. [25]
Industrial discharge is when waste products are released into the environment from manufacturing and chemical processing facilities. [26] This waste can include a wide variety of CECs like heavy metals, solvents, and various organic compounds that are not regularly detected for or removed by standard treatment processes. [27] These contaminants can accumulate in sediments and biota, posing risks to aquatic life and human health. The complexity and diversity of industrial discharge requires advanced treatment technologies and stricter regulatory frameworks to prevent CECs from contaminating the environment. Advanced oxidation processes and membrane technologies have been researched and shown to reduce CECs from industrial discharge, however there is an excessive cost to retrofit existing treatment facilities with this technology. [28]
Urban runoff is rainwater that runs through streets, gardens, and other urban surfaces, picking up various pollutants along the way. [29] These pollutants can include CECs like microplastics from synthetic materials, polycyclic aromatic hydrocarbons (PAHs) from vehicle exhausts, and pharmaceuticals from improperly disposed medications. [30] This untreated runoff can enter storm drains and eventually discharge into natural water bodies, often bypassing wastewater treatment facilities and leading to their accumulation in the environment, where they can cause harm to wildlife and potentially enter the human food chain. Permeable pavements and rain gardens are being implemented and tested in some urban areas to mitigate the effects of runoff, helping to filter pollutants before they reach the water system. [31]
Wastewater treatment plants (WWTPs) are designed to remove contaminants from domestic and industrial wastewater before it is released into the environment. [32] However, some WWTPs, particularly older or under-resourced ones are not equipped to effectively remove all CECs, such as advanced pharmaceuticals, personal care product ingredients, and certain types of industrial chemicals. [33] These substances can pass through the treatment process and enter aquatic ecosystems, [34] which creates a challenge for water treatment technology and emphasizes the need for ongoing research and infrastructure improvement to address the removal of CECs from wastewater. Advances like tertiary treatment stages, which incorporate advanced filtration and chemical removal techniques, are being tested to address the presence of CECs in waste, though widespread implementation is yet to be seen due to novelty, cost, and logistical challenges. [35]
There is an overlap of many anthropogenically sourced chemicals that humans are exposed to regularly. This makes it difficult to attribute negative health causality to a specific, isolated compound. EPA manages a Contaminant Candidate List to review substances that may need to be controlled in public water systems. [36] EPA has also listed twelve contaminants of emerging concern at federal facilities, with ranging origins, health effects, and means of exposure. [37] The twelve listed contaminants are as follows: Trichloropropane (TCP), Dioxane, Trinitrotoluene (TNT), Dinitrotoluene, Hexahydro-trinitro-triazane (RDX), N-nitroso-dimethylamine (NDMA), Perchlorate, Polybrominated biphenyls (PBBs), Tungsten, Polybrominated diphenyl ethers (PBDEs) and Nanomaterials.
The NORMAN network [38] enhances the exchange of information on emerging environmental substances. A Suspect List Exchange [39] (SLE) has been created to allow sharing of the many potential contaminants of emerging concern. The list contains more than 100,000 chemicals.
Table 1 is a summary of emerging contaminants currently listed on one EPA website and a review article. Detailed use and health risk of commonly identified CECs are listed in the table below. [40] [41]
Compound | Uses | Where it is Found | Health Risks |
---|---|---|---|
Trichloropropane (TCP) | Chemical intermediate, solvent, and cleaning product | TCPs are denser than water, so they sink to the bottom of aquifers and contaminate them, they also have a low capacity to be absorbed organically and leach into soil or evaporate, contaminating the air | Considered a likely carcinogen by NOAA |
Dioxane | Stabilizer of chlorinated solvents, manufacturing of PET, manufacturing by-product | Often at industrial sites, and they move rapidly from soil to groundwater, although it was phased out as part of the Montreal Protocol it is very resistant to bio-degradation and has been found at over 34 EPA sites | Rapid disruption of lung, liver, kidney, spleen, colon, and muscle tissue, may be toxic to developing fetuses and is a potential carcinogen |
Trinitrotoluene (TNT) | Pure explosive, military and underwater blasting | Major contaminant of groundwater and soils | Listed as cancer-causing by Office of Environmental Health, may cause carcinoma and bladder papilloma |
Dinitrotoluene | Intermediate to form TNT, explosive | Found in surface water, groundwater, and soil at hazardous waste sites, and may be released into the air as dust or aerosols | Considered a hepatocarcinogen and may cause ischemic heart disease, hepatobiliary cancer, and urothelial and renal cell cancers |
Hexahydro-trinitro-triazane (RDX) | Military explosive | Exists as particulate matter in the atmosphere, easily leaches into groundwater and aquifers from soil, does not readily evaporate from water | Decreased body weight, kidney and liver damage, possible carcinoma, insomnia, nausea, and tremor |
Nanomaterials | Broad classification of ultrafine particulate matter used in more than 1,800 consumer products and biomedical applications | Released as consumer waste or spillage, may be airborne, found in food, or in many diverse industrial processes | May translocate into the circulatory system primarily through the lungs, exposing the body to an accumulation of compounds in the liver, spleen, kidney, and brain |
N-nitroso-dimethylamine (NDMA) | Formed in the production of antioxidants, additives, softeners, and rocket fuel, and an unintended byproduct of the chlorination of waste and drinking water at treatment facilities | Broken down quickly when released into the air, but highly mobile when released into soil and will likely leach into groundwater, humans may be exposed by drinking contaminated water, ingesting contaminated food, or using products that contain NDMA | Probable carcinogen, evidence of liver damage, reduced function of kidneys and lungs |
Perchlorate | Manufacturing and combustion of solid rocket propellants, munitions, fireworks, airbag initiators, and flares | Highly soluble in water so it can greatly accumulate in groundwater, also accumulates in some food crop leaves and milk | Eye, skin, and respiratory irritation and in high volumes corrosion. Potentially disrupts thyroid hormones |
Perfluoro-octane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) | Used in additives and coatings, non-stick cookware, waterproof clothing, cardboard packaging, wire casing, and resistant tubing | During manufacturing, the compounds were released into the surrounding air, ground, and water, is resistant to typical environmental degradation processes and have been shown to bioaccumulate, found in oceans and Arctic, meaning they have a high capacity for transport | World Health Organization categorized possible carcinogen, may cause high cholesterol, increased liver enzymes, and adverse reproductive and developmental effects |
Polybrominated biphenyls (PBBs) | Flame retardant | Detected in the air, sediments, surface water, fish and other marine animals, they do not dissolve so they are not mobile in water but are volatile and prevalent in the atmosphere | Classified by International Agency for Research on Cancer as likely carcinogenic, neurotoxic, and thyroid, liver, and kidney toxicity as well as an endocrine disruptor |
Polybrominated diphenyl ethers (PBDEs) | Flame retardant and used in plastics, furniture, and other household products | Enter the environment through emissions, and has been detected in air, sediments, surface water, fish and other marine animals | Shown to be an endocrine disruptor as well as carcinogenic, also, may cause neural, liver, pancreatic, and thyroid toxicity |
Tungsten | A naturally occurring element which exists in various household products and military manufacturing | Tungsten is water-soluble under certain conditions and may be found in dangerous quantities in water sources | May cause respiratory complications, and investigated as a potential carcinogen by the CDC |
Diclofenac | Anti-inflammatory drug | Can be found in water treatment plant (WTP) effluents. Reported to be found in coastal waters as well | In large quantities can cause serious gastrointestinal toxicity. Severe ecotoxicity to selected breeds of animals |
Bisphenol A (BPA) | Industrial plastic production (polycarbonate plastics and epoxy resins) | Found to accumulate in water treatment plant (WTP) effluents | BPA is cytotoxic and mutagenic. It exerts various adverse effects on reproductive, immune, endocrine and nervous systems |
Sulfamethoxazole (SMX) | Antibiotics | Reported to be found in various freshwater systems | Common side effects include nausea, vomiting, loss of appetite, and skin rashes. It is a sulfonamide and bacteriostatic |
Carbamazepine | Anticonvulsant | Reported to be found in various freshwater systems and WTP effluents. | Common side effects include nausea and drowsiness. Serious side effects may include skin rashes, decreased bone marrow function, suicidal thoughts, or confusion. |
The environmental impact of CECs on aquatic life is broad. For example, endocrine-disrupting chemicals (EDCs) have the potential to imitate natural hormones, which can lead to reproductive failures and eventually population declines or increases in fish and amphibians. EDCs are found in a variety of common contaminants, including pesticides and industrial chemicals, and they can also lead to altered growth and reproduction in aquatic life (US EPA) (USGS.gov). [42] [43] Microplastics are another concern, as they can lead to physical blockages in the digestive tracts of aquatic organisms and act as paths for other toxins, leading to bioaccumulation and increase in concentration as they move up each level of the food chain. [42] These impacts not only threaten biodiversity but also the stability of aquatic ecosystems upon which many species depend. Ongoing monitoring and regulatory efforts are crucial for assessing the full scope of CECs' impacts and for the development of effective strategies to mitigate their presence in aquatic ecosystems (NOAA.gov). [44]
When CECs bypass water filtration systems and contaminate drinking water or accumulate in the food chain, they can also cause risks to human health. Chronic exposure to low doses of CECs has been linked to various health issues. For example, certain pharmaceutical CECs and EDCs have been associated with hormonal imbalances, increased risks of certain cancers, and developmental problems. [42] The antibiotics present in the environment can also contribute to the development of antibiotic-resistant bacteria, which poses a serious threat to human health by reducing the effectiveness of antibiotic treatments. [42] Studies have shown that even at low concentrations, the presence of CECs in drinking water can correlate with neurological disorders and can decrease cognitive function over time. [45] Certain perfluoroalkyl substances (PFAS), which are a type of CEC, have been linked to different adverse health outcomes like increased cholesterol levels, changes in liver enzymes, and reduced vaccine efficacy, which raises concerns about widespread exposure to these chemicals. [46] The CDC also identifies exposure to high levels of CECs with negative effects on the immune system, by compromising the body’s ability to fight infections and increasing the risk of rheumatological diseases. [45] Exposure to a combination of various CECs, which can occur through contaminated drinking water or food chains, may lead to cumulative on human health that are not yet fully understood. [45] [46]
Wildlife, particularly species reliant on aquatic environments, are exceptionally vulnerable to the disruptions caused by CECs. Terrestrial species can be exposed to CECs through contaminated food, water, and soil. These contaminants can cause pollution which can lead to mortality or can indirectly result in changes in behavior which affect essential activities like feeding and mating. Migratory species are especially at risk as they can spread the impact of CECs across various ecosystems. [42] [43] The health of wildlife populations is an important indicator of environmental quality, and the presence of CECs can signal broader ecological issues that require attention.
Detection and monitoring of CECs is done through a variety of sophisticated analytical techniques. High-performance liquid chromatography (HPLC) paired with mass spectrometry (MS) can help identify organic CECs, due to their high sensitivity and selectivity EPA. For volatile and semi-volatile compounds, gas chromatography (GC) coupled with MS is commonly used FDA. Metals and metalloids are typically analyzed using techniques like inductively coupled plasma mass spectrometry (ICP-MS), which allows for the simultaneous analysis of multiple elements USGS. The complications with monitoring CECs go past just detection. Their pathways across different environmental also must be monitored. This can be done with passive sampling devices, which accumulate contaminants over time and give a comprehensive view of contaminant levels at different locations NOAA. Biosensors are also used and integrated to detect specific contaminants rapidly, which is important for on-site monitoring applications NIH. The use of remote sensing and geographic information systems (GIS) for spatial analysis is expanding, these tools facilitate the tracking of pollution spread NASA Earth Science. Recent advancements in nanotechnology have led to the development of nano-sensors which can detect trace amounts of CECs Nature Nanotechnology.
There are sites with waste that would take hundreds of years to clean up and prevent further seepage and contamination into the water table and surrounding biosphere. In the United States, the environmental regulatory agencies on the federal level are primarily responsible for determining standards and statutes which guide policy and control in the state to prevent citizens and the environment from being exposed to harmful compounds. Emerging contaminants are examples of instances in which regulation did not do what it was supposed to, and communities have been left vulnerable to adverse health effects. Many states have assessed what can be done about emerging contaminants and currently view it as a serious issue, but only eight states have specific risk management programs addressing emerging contaminants. [47]
These are tactics and methods that aim to remediate the effects of certain, or all, CECs by preventing movement throughout the environment, or limiting their concentrations in certain environmental systems. It is particularly important to ensure that water treatment approaches do not simply move contaminants from effluent to sludge given the potential for sludge to be spread to land providing an alternative route to entering the environment.
For some emerging contaminants, several advanced technologies—sonolysis, photocatalysis, [41] Fenton-based oxidation [48] and ozonation—have treated pollutants in laboratory experiments. [49] Another technology is "enhanced coagulation" in which the treatment entity would work to optimize filtration by removing precursors to contamination through treatment. In the case of THMs, this meant lowering the pH, increasing the feed rate of coagulants, and encouraging domestic systems to operate with activated carbon filters and apparatuses that can perform reverse osmosis. [50] Although these methods are effective, they are costly, and there have been many instances of treatment plants being resistant to pay for the removal of pollution, especially if it wasn't created in the water treatment process as many EC's occur from runoff, past pollution sources, and personal care products. It is also difficult to incentivize states to have their own policies surrounding contamination because it can be burdensome for states to pay for screening and prevention processes. There is also an element of environmental injustice, in that lower income communities with less purchasing and political power cannot buy their own system for filtration and are regularly exposed to harmful compounds in drinking water and food. [51] However, recent treads for light-based systems shows great potential for such applications. With the decrease in cost of UV-LED systems and growing prevalence of solar powered systems, [41] it shows great potential to remove CECs while keeping costs low.
Researchers have suggested that metal–organic frameworks (MOFs) and MOF-based nano-adsorbents (MOF-NAs) could be used in the removal of certain CECs, such as pharmaceuticals and personal care products, especially in wastewater treatment. Widespread use of MOF-based nano-adsorbents has yet to be implemented due to complications created by the vast physicochemical properties that CECs contain. The removal of CECs largely depends on the structure and porosity of the MOF-NAs and the physicochemical compatibility of both the CECs and the MOF-NAs. [52] If a CEC is not compatible with the MOF-NA, then particular functional groups can be chemically added to increase compatibility between the two molecules. The addition of functional groups causes the reactions to rely on other chemical processes and mechanisms, such as hydrogen bonding, acid-base reactions, and complex electrostatic forces. [52] MOF-based nano-adsorbent remediation heavily relies on water-qualities, such as pH, in order for the reaction to be executed efficiently. MOF-NA remediation can also be used to efficiently remove other heavy metals and organic compounds in wastewater treatment.
Another method of possible remediation for CECs is through the use of membrane bioreactors (MBRs) that act through mechanisms of sorption and biodegradation. Membrane bioreactors have shown results on being able to filter out certain solutes and chemicals from wastewater through methods of microfiltration, but due to the extremely small size of CECs, MBRs must rely on other mechanisms in order to ensure the removal of CECs. One mechanism that MBRs use to remove CECs from wastewater is sorption. Sorption of the CECs to sludge deposits in the MBR's system can allow the deposits to sit and be bombarded with water, causing the eventual biodegradation of CECs in the membrane. Sorption of a particular CEC can be even more efficient in the system if the CEC is hydrophobic, causing it to move from the wastewater to the sludge deposits more quickly. [53]
The management of CECs has gained increasing attention in recent years due to their potential impact on public health and the environment. In response to these concerns, various governmental and international organizations have initiated efforts to address CECs through research, regulation, and public outreach.
In January 2024, the White House Office of Science and Technology Policy announced a coordinated federal research initiative to address CECs in surface waters. The initiative aims to enhance understanding of the sources, occurrence, and effects of CECs, as well as to develop effective strategies for their removal and management. [54]
Furthermore, the Organization for Economic Co-operation and Development (OECD) has been actively involved in addressing CECs. The OECD Workshop on Managing Contaminants of Emerging Concern in Surface Waters brought together experts from various countries to discuss challenges and solutions related to CECs, emphasizing the importance of international collaboration in tackling this global issue. [54]
These recent developments underscore the growing recognition of the need for concerted efforts to address the challenges posed by CECs to protect public health and the environment.
Advocacy efforts for the regulation of CECs are important to push for legislation and regulatory action. Environmental advocacy groups raise awareness about the potential risks associated with CECs and urge for the advancement of environmental protection policies. These groups lobby for the enhancement of water quality standards, particularly the inclusion of CECs in the monitoring and treatment protocols of wastewater facilities, resulting in improved effluent quality NECRI. Additionally, they push for a comprehensive detection framework, and advocate for precautionary policies to prevent the release of harmful chemicals into the environment (Environmental Working Group).
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance or energy. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants.
Sewage sludge is the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term "septage" also refers to sludge from simple wastewater treatment but is connected to simple on-site sanitation systems, such as septic tanks.
Chemical waste is any excess, unused, or unwanted chemical, especially those that cause damage to human health or the environment. Chemical waste may be classified as hazardous waste, non-hazardous waste, universal waste, or household hazardous waste. Hazardous waste is material that displays one or more of the following four characteristics: ignitability, corrosivity, reactivity, and toxicity. This information, along with chemical disposal requirements, is typically available on a chemical's Material Safety Data Sheet (MSDS). Radioactive waste requires special ways of handling and disposal due to its radioactive properties. Biohazardous waste, which may contain hazardous materials, is also handled differently.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through treatment of the water, can be assessed. The most common standards used to monitor and assess water quality convey the health of ecosystems, safety of human contact, extent of water pollution and condition of drinking water. Water quality has a significant impact on water supply and oftentimes determines supply options.
Water pollution is the contamination of water bodies, usually as a result of human activities, that has a negative impact on their uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants mix with these water bodies. Contaminants can come from one of four main sources: sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater. Water pollution is either surface water pollution or groundwater pollution. This form of pollution can lead to many problems, such as the degradation of aquatic ecosystems or spreading water-borne diseases when people use polluted water for drinking or irrigation. Another problem is that water pollution reduces the ecosystem services that the water resource would otherwise provide.
Environmental remediation is the cleanup of hazardous substances dealing with the removal, treatment and containment of pollution or contaminants from environmental media such as soil, groundwater, sediment. Remediation may be required by regulations before development of land revitalization projects. Developers who agree to voluntary cleanup may be offered incentives under state or municipal programs like New York State's Brownfield Cleanup Program. If remediation is done by removal the waste materials are simply transported off-site for disposal at another location. The waste material can also be contained by physical barriers like slurry walls. The use of slurry walls is well-established in the construction industry. The application of (low) pressure grouting, used to mitigate soil liquefaction risks in San Francisco and other earthquake zones, has achieved mixed results in field tests to create barriers, and site-specific results depend upon many variable conditions that can greatly impact outcomes.
Lindane, also known as gamma-hexachlorocyclohexane (γ-HCH), gammaxene, Gammallin and benzene hexachloride (BHC), is an organochlorine chemical and an isomer of hexachlorocyclohexane that has been used both as an agricultural insecticide and as a pharmaceutical treatment for lice and scabies.
Wastewater treatment is a process which removes and eliminates contaminants from wastewater and converts this into an effluent that can be returned to the water cycle. Once returned to the water cycle, the effluent creates an acceptable impact on the environment or is reused for various purposes. The treatment process takes place in a wastewater treatment plant. There are several kinds of wastewater which are treated at the appropriate type of wastewater treatment plant. For domestic wastewater, the treatment plant is called a Sewage Treatment. For industrial wastewater, treatment either takes place in a separate Industrial wastewater treatment, or in a sewage treatment plant. Further types of wastewater treatment plants include Agricultural wastewater treatment and leachate treatment plants.
Water reclamation is the process of converting municipal wastewater (sewage) or industrial wastewater into water that can be reused for a variety of purposes. Types of reuse include: urban reuse, agricultural reuse (irrigation), environmental reuse, industrial reuse, planned potable reuse, and de facto wastewater reuse. For example, reuse may include irrigation of gardens and agricultural fields or replenishing surface water and groundwater. Reused water may also be directed toward fulfilling certain needs in residences, businesses, and industry, and could even be treated to reach drinking water standards. The injection of reclaimed water into the water supply distribution system is known as direct potable reuse. However, drinking reclaimed water is not a typical practice. Treated municipal wastewater reuse for irrigation is a long-established practice, especially in arid countries. Reusing wastewater as part of sustainable water management allows water to remain as an alternative water source for human activities. This can reduce scarcity and alleviate pressures on groundwater and other natural water bodies.
Biosolids are solid organic matter recovered from a sewage treatment process and used as fertilizer. In the past, it was common for farmers to use animal manure to improve their soil fertility. In the 1920s, the farming community began also to use sewage sludge from local wastewater treatment plants. Scientific research over many years has confirmed that these biosolids contain similar nutrients to those in animal manures. Biosolids that are used as fertilizer in farming are usually treated to help to prevent disease-causing pathogens from spreading to the public. Some sewage sludge can not qualify as biosolids due to persistent, bioaccumulative and toxic chemicals, radionuclides, and heavy metals at levels sufficient to contaminate soil and water when applied to land.
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans. This applies to industries that generate wastewater with high concentrations of organic matter, toxic pollutants or nutrients such as ammonia. Some industries install a pre-treatment system to remove some pollutants, and then discharge the partially treated wastewater to the municipal sewer system.
Green nanotechnology refers to the use of nanotechnology to enhance the environmental sustainability of processes producing negative externalities. It also refers to the use of the products of nanotechnology to enhance sustainability. It includes making green nano-products and using nano-products in support of sustainability.
Per- and polyfluoroalkyl substances are a group of synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. The PubChem database lists more than 6 million unique compounds in this group. PFASs started being used in the mid-20th century to make fluoropolymer coatings and products that resist heat, oil, stains, grease, and water. They are used in a variety of products including waterproof clothing, furniture, adhesives, food packaging, heat-resistant non-stick cooking surfaces, and the insulation of electrical wire. They have played a key economic role for companies such as DuPont, 3M, and W. L. Gore & Associates that use them to produce widely known materials such as Teflon or Gore-Tex.
The environmental effect of pharmaceuticals and personal care products (PPCPs) is being investigated since at least the 1990s. PPCPs include substances used by individuals for personal health or cosmetic reasons and the products used by agribusiness to boost growth or health of livestock. More than twenty million tons of PPCPs are produced every year. The European Union has declared pharmaceutical residues with the potential of contamination of water and soil to be "priority substances".[3]
The term environmental persistent pharmaceutical pollutants (EPPP) was first suggested in the nomination in 2010 of pharmaceuticals and environment as an emerging issue in a Strategic Approach to International Chemicals Management (SAICM) by the International Society of Doctors for the Environment (ISDE). The occurring problems from EPPPs are in parallel explained under environmental impact of pharmaceuticals and personal care products (PPCP). The European Union summarizes pharmaceutical residues with the potential of contamination of water and soil together with other micropollutants under "priority substances".
Drug pollution or pharmaceutical pollution is pollution of the environment with pharmaceutical drugs and their metabolites, which reach the aquatic environment through wastewater. Drug pollution is therefore mainly a form of water pollution.
Nanoremediation is the use of nanoparticles for environmental remediation. It is being explored to treat ground water, wastewater, soil, sediment, or other contaminated environmental materials. Nanoremediation is an emerging industry; by 2009, nanoremediation technologies had been documented in at least 44 cleanup sites around the world, predominantly in the United States. In Europe, nanoremediation is being investigated by the EC funded NanoRem Project. A report produced by the NanoRem consortium has identified around 70 nanoremediation projects worldwide at pilot or full scale. During nanoremediation, a nanoparticle agent must be brought into contact with the target contaminant under conditions that allow a detoxifying or immobilizing reaction. This process typically involves a pump-and-treat process or in situ application.
Groundwater pollution occurs when pollutants are released to the ground and make their way into groundwater. This type of water pollution can also occur naturally due to the presence of a minor and unwanted constituent, contaminant, or impurity in the groundwater, in which case it is more likely referred to as contamination rather than pollution. Groundwater pollution can occur from on-site sanitation systems, landfill leachate, effluent from wastewater treatment plants, leaking sewers, petrol filling stations, hydraulic fracturing (fracking) or from over application of fertilizers in agriculture. Pollution can also occur from naturally occurring contaminants, such as arsenic or fluoride. Using polluted groundwater causes hazards to public health through poisoning or the spread of disease.
Despo C. Fatta-Kassinos is a chemical and environmental engineer, academic and author. She is a professor in the Department of Civil and Environmental Engineering and the first director of Nireas-International Water Research Center (Nireas-IWRC) at the University of Cyprus (2010–2022). She has been named a Highly Cited Researcher by Web of Science, Clarivate Analytics.
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