EDITOR: | July 25th, 2017 | 1 Comment

Lead: Valuable Metal but Toxic at Any Concentration — What is Society to do?

| July 25, 2017 | 1 Comment
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Six millennia ago an observant individual may have noticed that a colored rock in a campfire changed form and produced a quite malleable material with unique and fascinating properties. Nriagu [1a] described a possible scenario suggested by J. Percy in 1870 as follows: if he were to throw it (low melting lead sulfide, galena) on his blazing wood fire even he could hardly fail to observe the remarkable change it might thereby undergo. The hard brittle ore might in a greater or less degree be transformed, as though by magic, into soft malleable lead.

Lead (Pb) is a remarkable metal. Corrosion-resistant, dense, ductile, and malleable, it soon had numerous uses in primitive societies [2]. Lead production rose continually during the Copper, Bronze, and Iron ages as its value was recognized [1,3]. Lead was a by-product of silver (Ag) production, which helped assure its use. A maximum of approximately 80,000 metric tons of Pb per year was used during the development of Roman power and influence throughout the Mediterranean world. Mining districts for Pb were found in Spain, the Balkans, Greece, and Asia Minor. Lead production decreased sharply during the decline of the western Roman Empire, reaching a few thousand tons per year until about A.D. 1000 when Pb and Ag mines were discovered in Central Europe.

Known uses for Pb in the ancient and medieval world included: non-ferrous alloys; pewter and solder; coinage; glass; glazes and enamel; plumbing; stationery; roofs, gutters, and downspouts; burial of the dead; vases, vessels, and kitchenware; statuettes and figurines; ship building and other naval purposes; standard weights; projectiles in warfare; pigments; medicine; and food preservatives and colorants. Castles and cathedrals of Europe contain considerable quantities of Pb in decorative fixtures, roofs, pipes, and windows [2]. These uses insured that many people had close association with Pb in mining, in making products, and in their daily lives affording ample opportunity for exposure by workers and the general population.

Lead toxicity to humans has been recognized for thousands of years [1,4,6a]. Such phrases as gleaming deadly white lead and lead makes the mind give way date to 2000 years ago. Shakespeare mentions Pb often [1]. No occupational disease has had so much written about it for so long, as has plumbism or lead poisoning [1]. The number of people exposed to Pb poisoning through history has been large. Estimates are that approximately 140,000 workers per year may have been exposed in Roman times. By comparison, OSHA estimated in 1978 that 800,000 workers in 40 industries in the United States (U.S.) were exposed to Pb [2]. Nriagu [1] has documented the considerable evidence attributing the decline of the Roman Empire to plumbism. This disease was much more prevalent among the aristocrat class than plebian and slave classes because members of the aristocrat class had greater access to lead, especially in utensils and wine sweetened with Pb salts. Abortifacient properties of lead salts have been known since antiquity [1]. Current clinical data show that exposure to moderate and high doses of Pb can cause reproductive failures in both males and females. A second effect of plumbism is permanent mental and physical damage. Despite knowledge of Pb toxicity, the incorrect belief persisted well into the 20th century that adverse effects of Pb poisoning were reversible if the patient did not die in the acute phase [4]. As knowledge and experience have increased, recommended blood Pb concentration levels for children have decreased, from 60 micrograms/deciliter (µg dL-1) in 1960 to 5 µg dL-1 in 2012 [5]. Present consensus is that there is no safe level for Pb [6b].

Why is Lead So Dangerous? The human body when properly functioning is a marvelous machine. As with mechanical machines, its successful operation depends on having available necessary components and ensuring that these components function properly. Iron (Fe), copper (Cu), and zinc (Zn) are essential constituents of enzymes, proteins, and other species that do not work properly without adequate supplies of these essential metals. Zinc, for instance, is required for proper metabolic activity of about 300 enzymes in the human body [7]. Average adult human bodies contain about 3 g of Zn, 5g of Fe, and 0.3 g of Cu. Zinc is critical to a whole host of body processes including tissue growth and maintenance, wound healing, immune system function, prostaglandin production, bone mineralization, proper thyroid function, cognitive functions, fetal growth, sperm production, and more. Zinc is essential for enzymes and other chemical entities to perform their proper function in children and fetuses in their developmental phase. Iron and Cu have similar important functions, such as the role of Fe in hemoglobin synthesis and action.

Ingestion of Pb via air, water, or soil results in displacement of essential metals in enzymes, proteins, and carbohydrates [8]. Lead will win this competition in most cases because it usually has similar or greater affinity for ligand binding sites at key functional groups. Many organs or organ systems are potential targets for Pb and a wide range of negative biological effects have been documented [1,4]. Once a site is occupied by Pb, the normal function of that site ceases. Depending on the biological system, when enough sites are compromised clinical effects become visible. In extreme cases, death results. Disruption of function has been reported in haem biosynthesis and nervous, kidney, reproduction, cardiovascular, hepatic, endocrine, and gastrointestinal systems [8]. Clinical effects include for children: impaired development of the brain and nervous system; for adults: increased risk of high blood pressure and kidney damage; and for pregnant women: miscarriage, stillbirth, premature birth, low birth weight, and various minor malformations [9]. Serious neurological disorders, such as autism, have been associated with elevated blood Pb levels [10].

Upon entering the body, Pb is distributed to organs such as the brain, kidneys, liver, and bones. Ingested Pb accumulates over time in teeth and bones, where about 90% of it is stored [10]. Stored Pb may be remobilized during pregnancy, exposing the fetus to its toxic effects. Children, especially the very young (including the developing fetus) are especially vulnerable to Pb poisoning because organs are being developed and essential metals are required for this development [9,10]. Without proper functioning of key enzymes, development is curtailed with serious negative results including learning problems, cognitive dysfunction, and behavior disorders [5,11]. Replacement of Zn by Pb, for example, can result in impairment of enzymes required for growth, metabolism, and other functions. It is evident that Pb in any amount can disrupt Zn metabolism to some degree. This explanation of Zn-Pb interaction supports the conclusion that no level of Pb is safe and that Pb is particularly dangerous for developing organs, tissues, etc. found in fetuses and children where rapid growth is taking place [5,10].

Health Effects of Lead on Humans. Industrialization of Western Europe and the United States in the 19th century provided opportunity for expanded use of this valuable metal. Uses stemming from Roman days plus many new ones resulted in production of large amounts of Pb. Advent of the electrical age and new forms of communication in the late 19th and early 20th centuries, accelerated by technological developments in World War I, resulted in new Pb uses including bearing metals, cable covering, caulking Pb, solders and type metal [2]. Growth in use of public and private motorized vehicles and associated use of starting-lighting-ignition (SLI) lead-acid storage batteries and terne metal for gas tanks after World War I greatly expanded Pb usage. Demand for Pb increased further by its use in paints, as an additive in gasoline, and radiation-shielding in medical applications. These uses expanded rapidly as population and national economies grew. In the past few decades, Pb has found increased use in high technology products and, subsequently, is found in electronic waste (e-waste). These activities have increased exposure to Pb pollution by miners, workers, and the public, especially children.

Lead exposure at firing ranges has recently come under review with some interesting statistics [10]. Shooting guns at firing ranges is an occupational necessity for security personnel, police officers, members of the military, and increasingly a recreational activity by the public. In the U.S. alone, an estimated 16,000-18,000 firing ranges exist. Laidlaw, et al. [10] point out that discharge of Pb dust and gases is a consequence of shooting firearms. The United States Geological Survey estimated that in 2012 about 60,000 metric tonnes of Pb were used in ammunition and bullets in the U.S. [10]. Nearly all blood Pb levels of persons tested in the review by Laidlaw, et al. [10] exceeded the recommended level of 5µg dL-1, many by large amounts. The conclusion was that firing ranges constitute a significant and currently largely unmanaged public health concern, especially for children and pregnant women.

Society has been slow to recognize the prevalence of health-related problems associated with Pb use and to act to alleviate them. Government officials have been slow to pass and enforce legislation designed to protect citizens, especially children, from the effects of Pb pollution. There has been a significant shift in Pb end-use patterns beginning in the last decades of the 20th century. Three examples of Pb pollution are presented involving use of tetraethyl lead in gasoline, use of Pb in paint, and the current problem of Pb in e-waste treated by informal recycling in Guiyu, China.

Tetraethyl lead was added to gasoline used for motor fuel beginning in the 1920s [5]. This compound was remarkable. It reduced engine knocking, boosted octane ratings, and helped with wear and tear on valve seats within the motor. A significant industry developed. Despite protests by scientists and others together with accumulating evidence of toxic Pb effects, use of tetraethyl Pb persisted for over half a century worldwide. In 1970, the Clean Air Act was signed into law by President Nixon. Twenty years later, Pb was banned from gasoline in the U.S. with the ban taking effect in 1995. In 2017, the ban on leaded gasoline is nearly universal as other nations have taken similar action.

By the early 1900s, it was recognized that Pb-based paints posed an identified hazard to children [1]. If a child ate paint chips, seizure, coma, and death could result. It was also known that learning and behavioral disabilities were a direct result of Pb pollution. Despite this knowledge, it was not until 1976 that leaded paint was effectively banned in the U.S. by the Consumer Product Safety Commission. Levels of Pb found in the blood of children were reduced by more than 80% from 1976 to 1990, undoubtedly because of effective legislation banning leaded gasoline and Pb-based paints.

Guiyu, China has a 30-year e-waste dismantling history and is one of the largest e-waste destinations and recycling areas in the world [12,13]. Approximately 60-80% of families in Guiyu are engaged in e-waste recycling operations run by small scale family workshops. E-waste is a new, but growing and expansive source of pollution for our planet. Until about 50 years ago discarded waste was, primarily, biodegradable being generated from domestic activities involving plant-based materials [12]. Waste composition has changed markedly over the past half century to include many synthetic components and spent high technology products that contain toxic metals. Increasingly, spread of toxic metals, including Pb, throughout the planet has come from industrial sources including mining; fossil fuel combustion; discard of spent products and waste solutions containing toxic metals into landfill and tailings; and inefficient, largely unregulated, informal recycling in developing nations of precious metals in spent e-waste. Spent e-waste is treated for recovery of precious metals, but Pb and other toxic metals present are discarded since their recovery is not economic.

Zeng, et al. [13] have studied children in Guiyu, China with health impairment by heavy metals, including Pb. About 60 chemical elements can be found in e-waste, many of which are known to be hazardous. These metals are used in products such as circuit boards, semi-conductor chips, cathode ray tubes, coatings, and batteries. Informal and hazardous e-waste recycling activities including open burning of products; extraction of precious metals by untrained persons using acids, cyanide, and other harsh chemicals; and use of few environmental or personal protections result in a threat to human health of residents, especially children and pregnant women. Significant positive associations were found by Zeng, et al. [13] between heavy metals, including Pb, and negative respiratory, cardiovascular, nervous, reproductive, and urinary toxicity conditions in children. Comparison of selected health effects including lung function, nervous system, immune system, reproductive system, skeletal system, growth, DNA damage, and chromosome damage for children from Guiyu and a comparable city outside the pollution zone showed marked impairments for Guiyu children. These authors point out that heavy metals, including Pb, are pernicious because they bio-accumulate in the human body where they have lasting effects, especially on developing organs and tissues of growing children and pregnant women.

These examples demonstrate the effectiveness of positive action by enlightened public and responsible government officials in tackling a serious public health global problem in the cases of tetraethyl lead and Pb-based paints. Unfortunately, the time required for action allowed many Pb poisoning cases to occur with much human suffering. The case of Guiyu is representative of many similar situations, especially in developing nations, that have been documented [14-16]. The prevalence of toxic metal poisoning is large in these areas. The magnitude of the global problem of disease resulting from Pb exposure is summarized by The Institute of Health Metrics and Evaluation (IHME) as follows: in 2013 lead exposure accounted for 853,000 deaths due to long-term effects on health, with the highest burden in low and middle-income countries. IHME also estimated that lead exposure accounted for 9.3% of the global burden of idiopathic intellectual disability, 4% of the global burden of ischaemic heart disease and 6.6% of the global burden of stroke [9].

What are the Origins of Pb Pollution? Lead is a ubiquitous pollutant in the ecosystem [8]. There is evidence that this has not always been the case. More, et al. [6] used high resolution inductively coupled mass spectrometry (ICP-MS) and ultra-high-resolution laser ablation inductively coupled mass spectrometry (LA-ICP-MS) to analyze atmospheric Pb deposition present in an ice core extracted from the high Alpine glacier Colle Gnifetti, in the Swiss-Italian Alps. In a combined scientific-historical study, these workers found that low levels of Pb at or approaching natural background occurred only in a single four-year period in the approximately 2000 years documented in the new ice core, during the Black Death (ca. 1349-1353 C.E.), the most devastating pandemic in Eurasian history. Historical evidence shows that mining activity ceased upwind of the core site from about 1349-1353, while concurrently Pb concentrations on the glacier dropped to levels below detection, an order of magnitude beneath figures deemed low in earlier studies. Their conclusion is that these new data show that human activity has polluted European air almost uninterruptedly for the last about 2000 years. Only a devastating collapse in population and economic activity caused by pandemic disease reduced atmospheric pollution to what can now more accurately be termed background or natural levels. These results provide a challenge to assumptions that widespread pollution began with the onset of the Industrial Revolution in the 1700s and 1800s and that Pb detected before that era represents natural or background levels. The new research shows that Pb from mining and smelting, which has occurred for thousands of years, was detectable well before the Industrial Revolution and that only when these activities were essentially halted in 1349-1353 by the plague did Pb pollution decline to natural levels.

Exposure to Pb comes from a variety of sources including mining and smelting of primary Pb ores and of sulfide ores of metals such as Zn, Fe, Cu, and Sn where Pb is a by-product metal. Widespread use of Pb in small amounts in high technology products and its presence in industrial waste streams at low concentration levels have created significant sources of Pb pollution globally. E-waste is one of the most rapidly growing waste streams [14]. Approximately 50 million tons of e-waste are generated annually on a global basis and this amount is growing. Recycling rates of Pb from this waste are very low [17]. The low economic value of Pb and the difficulty of separating and recovering it probably account for the low recycling rates. The example of Guiyu described earlier illustrates health effects resulting from high exposure of workers and children to Pb in informal recycling of e-waste. Lead in industrial waste streams is generally consigned to tailings, landfill, or incineration. In developing countries, legislative requirements for these disposal processes are often not enforced resulting in widespread Pb pollution [15]. Opportunity exists for development of technologies capable of separating Pb from these secondary sources and recovering it for value or environmentally safe disposal.

Marx, et al. have published a comprehensive account of global-scale patterns in anthropogenic Pb contamination from ancient times to the present reconstructed from natural archives including lakes, peats, and ice fields [18]. These natural archives receive predominantly atmospheric input and are geomorphically stable. Today, Pb is emitted to the atmosphere mainly from fossil fuel combustion (85 gigagram, Gg yr-1), metal production (25 Gg yr-1), fabrication/manufacturing (6.4 Gg yr-1), agriculture (1.8 Gg yr-1), and waste disposal (0.9 Gg yr-1). One gigagram = 109 grams = 1,000 tonnes. Lead has been mined and used from ancient times [1], but the onset of the industrial revolution in the 19th century resulted in greatly increased production of this valuable, but toxic metal. Lead is present in appreciable amounts in coal [19]. The enormous quantities of coal burned by the electrical industry and smelting operations result in emission of large amounts of Pb to the environment and accumulation of Pb in coal ash. Because Pb is not degradable, it persists in some form and presents danger to humans and animals, especially near the source of emission. It has been estimated that a boiler burning a million pounds of lignite coal will release 420 pounds of Pb into the atmosphere [19].

Separation and Recovery of Lead from Industrial Effluents and Other Secondary Sources. Over 80% of today’s global lead use is for batteries in gasoline and diesel-driven vehicles and for backup power supplies [2,17]. Collection and pre-processing rates from these uses are estimated to be 90-95% because of stringent regulations worldwide. The result is a nearly closed-loop system for these batteries. In developing countries, this recycling may, depending on enforcement of regulations, be carried out by using unsafe procedures resulting in risk of Pb poisoning.

In contrast to batteries, recycling rates of Pb and other toxic metals from e-waste, mining operation effluents, ore beneficiation processes where it may be present as a by-product, and scrap production are low [17]. As in Guiyu, these metals are discarded with spent products into landfill, incinerated, or sent to waste dumps. Here, they are subject to weathering and may become hazardous by entering water, soil, or atmosphere in uncontrolled fashion.

Separation of Pb from secondary sources and recovery of it for reuse or safe environmental disposal is a worthwhile goal in efforts to attain metal sustainability and reduce the environmental burden. Traditional technologies for removing metal ions, including Pb, from aqueous streams include adsorption on new adsorbents, membrane filtration, chemical precipitation, lime coagulation, ion exchange, reverse osmosis, and solvent extraction [20,21]. These technologies are not adequate economically for the task of separating metals from spent e-wastes and other secondary sources where metals are usually present at low concentrations and in the presence of complex matrices of metals having similar chemical properties [22-24]. Many process steps are used for separations with these technologies and they consume large amounts of chemicals, generate new wastes, and use large amounts of waste water. These characteristics of traditional technologies are traceable, in large part, to complex separation systems with low selectivity for the metal of interest, use of organic solvents in the separation process, and low ability to concentrate the desired metal for recovery. Complex environmental treatment systems are required to compensate for lack of selectivity. Because of these limitations, capital expenses (capex) and operating expenses (opex) are large resulting in consignment of waste solutions or spent products to landfill with the metals they contain.

Molecular Recognition Technology (MRT) provides a tested green engineering/green chemistry means for separation and recovery of Pb (and other toxic metals) from ore beneficiation and secondary sources [25]. No organic solvents or harsh chemicals are used in MRT processes. Characteristics of MRT processes that make them effective for these separations include

  1. use of a gravity-operated simplified procedure consisting of a column loaded with a SuperLig® resin that has high selectivity for Pb over other metals present in a feed solution, even if these metals are present at much higher concentrations,
  2. ability of the SuperLig® resin to separate Pb even at mg L-1 or lower concentrations,
  3. ability to concentrate separated Pb by 100-fold or more in an elution process using mild chemicals, and
  4. ability to recover Pb for resale or disposal in a safe environmental manner.

Simplicity of the system coupled with high metal selectivity and recovery of concentrated target metals minimizes waste generation, water consumption, and energy use. Compared to conventional technologies, MRT processes have much lower capex and opex costs.

Separation and recovery of Pb from a secondary source using MRT is illustrated by removal of Pb from fly ash generated by ash melting. Incineration is a common means of preparing wastes for disposal. Fly ash resulting from refuse incineration often contains a variety of metals including toxic Pb, Cd, and As. Mishima, Kataoke, and Izatt [26] reported a 30 kg hr-1 pilot plant study, undertaken by Takuma Co., Ltd., (Japan), of the selective removal of Pb from a feed solution formed by acid extraction of melted fly ash generated in a plasma furnace. The feed solution consisted of Pb (1,800 mg L-1), Fe (350 mg L-1), Al (550 mg L-1), Cu (360 mg L-1), Zn (6,400 mg L-1), Cd (62 mg L-1), As (1 mg L-1), and Sb (18 mg L-1). Passage of this solution through an MRT system consisting of four columns in series packed with Pb-selective SuperLig® 141 resulted in quantitative removal of Pb while remaining metals were not retained, but passed on to the raffinate. Elution of the column using a small volume of water resulted in recovery of 100% of the Pb in pure form. Ability to concentrate the separated Pb many hundred-fold in the column elution step facilitates the recovery of this metal for resale or safe environmental disposal. Conventional separation technologies are not able to concentrate Pb in this fashion making recovery of Pb difficult, especially from solutions where it is present at low concentrations.

The MRT procedure has been used for separation and recovery at high purity of metals from a variety of secondary sources including alloy scrap, industrial process streams, plating solutions, acid mine drainage streams, industrial waste streams, mine leach streams, fly ash, and others [27]. MRT processes can also be used to separate and recover metals from large volumes of contaminated water. The simplicity and versatility of the MRT procedure make it an ideal candidate for separation and recovery of Pb from many secondary sources. MRT is characterized by the ability to selectively separate metals from dilute solutions containing complex matrices in high purity. Recovery is also at high purity allowing reuse of the metal or disposal using environmentally safe procedures. These are characteristics needed for economic separation and recovery of Pb from many secondary sources.

References

1. (a) Nriagu, J.O., 1983. Lead and Lead Poisoning in Antiquity, Wiley-Interscience, New York; (b) Hernberg, S., 2000. Lead Poisoning in a Historical Perspective, American Journal of Industrial Medicine, 38, 244-254.

2. Lead Statistics and Information, 2017. Accessed July 15, 2017.

3. Hong, S., Candelone, J.-P., Patterson, C.C., Boultron, C.F., 1994. Greenland Ice Evidence of Hemispheric Lead Pollution Two Millennia Ago by Greek and Roman Civilizations, Science, 265, 1841-1843.

4. Greydanus, D.E., Merrick, J., 2016. From Nicander of Colophon, Ludwig van Beethoven, Vincent van Gogh, and Now the Children of Flint, Michigan, United States: The Long, Lethal Legacy of Lead Neurotoxicity Tragically Lingers, Journal of Pain Management, 9, 23-31.

5. American Academy of Pediatrics Policy Statement: Prevention of Childhood Lead Toxicity, June 2016. Accessed July 13, 2017.

6. (a) More, A.F., Spaulding, N.E., Bohleber, P., Handley, M.J., Hoffmann, H., Korotkikh, E.V., Kurbatov, A.V., Loveluck, C.P., Sneed, S.B., McCormick, M., Mayewski, P.A., 2017. Next Generation Ice Core Technology Reveals True Minimum Natural Levels of Lead (Pb) in the Atmosphere: Insights from the Black Death, GeoHealth, published online 31 May 2017. <file:///D:/Users/Owner/Downloads/More_GeoHealth.2017%20(3).pdf Accessed July 15, 2017; (b) Editor’s Pick: Probing the Black Death for Lead Pollution Insights, HARVARDgazette, May 30,2017. Accessed July 15, 2017.

7. Deshpande, J.E., Joshi, M.M., Giri, P.A., 2012. Zinc: The Trace Element of Major Importance in Human Nutrition and Health, International Journal of Medical Science and Public Health, 2, 1-6.

8. Air Quality Guidelines for Europe, Second Edition, 2000. Chapter 6.7 Lead, <file:///D:/Users/Owner/Downloads/WHO_Lead-Ch.6.7.2001.pdf> Accessed July 13, 2017.

9. World Health Organization, Media Center 2016. Lead Poisoning and Health, Fact Sheet, Accessed July 13, 2017.

10. Laidlaw, M.A.S., Filippelli, G., Mielke, H., Gulson, B., Ball, A.S., 2017. Lead Exposure at Firing Ranges—A Review, Environmental Health, 16:34, 1-15.

11. Reyes, J.W., 2015. Lead Exposure and Behavior: Effects on Antisocial and Risky Behavior Among Children and Adolescents, Economic Inquiry, 53, 1580-1605.

12. Anetor, G.O., 2016. Waste Dumps in Local Communities in Developing Countries and Hidden Danger to Health, Perspectives in Public Health, 136, 245-251.

13. Zeng, X., Xu, X., Boezen, H.M., Huo, X., 2016. Children with Health Impairments by Heavy Metals in an E-waste Recycling Area, Chemosphere, 148, 408-415.

14. Williams, I.D., 2016. Global Metal Reuse, and Formal and Informal Recycling from Electronic and Other High-Tech Wastes, In Metal Sustainability: Global Challenges, Consequences, and Prospects, Izatt, R.M. (Ed.), Wiley, Oxford, U.K., pp 21-51.

15. Osibanjo, O., Nnorom, I.C., Adie, G.U., Ogundiran, M.B., Adeyi, A.A., 2016. Global Management of Electronic Wastes: Challenges Facing Developing and Economy-in-Transition Countries, In Izatt, R.M. (Ed.), Metal Sustainability: Global Challenges, Consequences, and Prospects, Wiley, Oxford, U.K., pp. 52-84.

16. Streicher-Porte, M., Chi., X., Yang, J., 2016. E-waste Recycling in China: Status Quo in 2015, In Izatt, R.M. (Ed.), Metal Sustainability: Global Challenges, Consequences, and Prospects, Wiley, Oxford, U.K., pp. 134-150.

17. Reck, B,K., Graedel, T.E., 2012. Challenges in Metal Recycling, Science, 337, 690-695.

18. Marx, S.K., Rahsid, S., Stromsoe, N., 2016. Global-scale Patterns in Anthropogenic Pb Contamination Reconstructed from Natural Archives, Environmental Pollution, 213, 283-298.

19. Heavy Metals and Coal, Accessed July 13, 2017.

20. Kushwah, A., Srivastav, J.K., Palsania, J., 2015. Biosoption of Heavy Metals: A Review, European Journal of Biotechnology and Bioscience, 3, 51-55.

21. Gunatilake, S.K., 2015. Methods of Removing Heavy Metals from Industrial Wastewater, Journal of Multidisciplinary Engineering Science Studies, 1, 12-18.

22. O’Connor, M.P., Zimmerman, J.B., Anastas, P.T., Plata, D.L., 2016. A Strategy for Material Supply Chain Sustainability: Enabling a Circular Economy in the Electronics Industry through Green Engineering, ACS Sustainable Chemistry and Engineering, 4, 5879-5888.

23. Iannicelli-Zubiani, E. M., Giani, M.I., Recanati, F., Dotelli, G., Stefano, Puricelli, S., Cinzia Cristiani, C., 2017. Environmental Impacts of a Hydrometallurgical Process for Electronic Waste Treatment: A Life Cycle Assessment Case Study, Journal of Cleaner Production, 140, 1204-1216.

24. Izatt, S.R., Bruening, R.L., Izatt, N.E., Izatt, R.M., 2017, submitted. Precious Metal Separation and Recovery from Primary and Secondary Sources Using Molecular Recognition Technology, Journal of the International Precious Metals Institute.

25. Izatt, R.M., Izatt, S.R., Izatt, N.E., Krakowiak, K.E., Bruening, R L., Navarro, L., 2015. Industrial Applications of Molecular Recognition Technology to Green Chemistry Separations of Platinum Group Metals and Selective Removal of Metal Impurities from Process Streams, Green Chemistry, 17, 2236-2245.

26. Mishima, H., Iwasaki, S., Kataoka, S., Izatt, S.R. 1998. Proceedings of the 19th Annual Conference of the Japan Waste Management Association, pp 1-5; Mishima, H., et. al. 1996. Proceedings of the 18th Annual Conference of Japan Waste Management Association, pp 89-91.

27. Izatt, R.M., Izatt, S.R., Izatt, N.E., Krakowiak, K.E., Bruening, R.L., 2017. Green Chemistry Molecular Recognition Processes Applied to Metal Separations in Ore Beneficiation, Element Recycling, Metal Remediation, and Elemental Analysis. In Beach, E.S. and Kundu, S. (Eds.), Handbook of Green Chemistry Volume 12 – Tools for Green Chemistry, (Anastas, P.T., (Ed.). Handbook of Green Chemistry Series.) Wiley-VCH, Weinheim, Germany, pp 189-240.


Reed M. Izatt, PhD

Editor:

Reed M. Izatt received a BS degree in Chemistry from Utah State University (1951) and a PhD degree in Chemistry with an Earth Sciences minor ... <Read more about Reed M. Izatt, PhD>


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Comments

  • hackenzack

    Of big concern lately are plumbing and fixtures that leach lead especially corrosivity issues loom such as in Flint. What is the feasibility for a simple, lead specific, inline MRT water filter? Those would sell.

    July 26, 2017 - 4:46 PM

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