Chemicals in Medical Laboratory and Its Impact on Healthcare Workers and Biotic Factors: Analysis Through the Prism of Environmental Bioethics

Abstract

From an occupational health perspective, if not stored, handled, and disposed of properly, laboratory chemicals exhibit hazardous properties such as flammability, corrosion, and explosibility. Additionally, they can also cause a range of health effects in handlers, including irritation, sensitization, and carcinogenicity. Additionally, the chemical waste generated during the planned assay is a significant byproduct and, if left untreated, can cause detrimental effects on both living organisms and non-living elements when released into the environment. Chemically, laboratory waste contains reagents, organic and inorganic compounds, and diagnostic stains. These agents are more toxic and hazardous than residential waste and affect the personnel handling them and the environments in which they are released. Considering this, it is crucial to adhere to waste management regulations during the various stages including generation, segregation, collection, storage, transportation, and treatment. This is extremely important and necessary if we are to avoid harm to individuals and environmental contamination. This review encompasses the examination of laboratory medical waste, various categories of chemical waste, and strategies to minimize and ensure the safe disposal of these toxic agents. As far as the authors are aware, this is the first review that focuses on the effects of laboratory-generated chemical wastes and environmental ethics. This is a neglected topic in healthcare education, and this review will serve as a valuable resource for students.

1. Introduction

Medical laboratory science, including clinical chemistry, hematology, histopathology, and microbiology, plays an important role in the entire healthcare system. The assays performed verify the clinician’s diagnosis, eliminating probable misdiagnosis, detecting a specific disease, and assisting in the revision of the treatment strategy, all of which are crucial in human care, treatment, and recovery [1,2]. However, the medical laboratory environment is not devoid of hazards, and the staff working are consistently subjected to certain risks that are prevalent in various other fields, while some challenges remain specific to this profession.

In medical laboratories, a range of chemicals are used for assays, and most of them pose a threat to the health of the personnel. The degree and amount of exposure are dependent on how affirmatively the laboratories adhere to the mandatory Standard Operating Procedures (SOPs). The hospital laboratory uses a range of chemicals including oxidizers like nitrates and nitrites, chlorates and perchlorates, peroxides, sulfates, and persulphates; flammable liquids like methanol, ethanol, acetone, xylene, toluene, ethyl acetate, and benzene; sulfides; and acids like acetic acid and hydrochloric acid. Toxic chemicals can take effect both locally at the point of contact and systemically. Reactive or corrosive chemicals like acids, alkalis, or oxidizing agents cause severe injuries [1,2]. Toxins that pass via the bloodstream can cause systemic harm to a variety of tissues and organs and display a plethora of ill effects [1].

In addition to the dangers encountered in the workplace, biomedical waste disposal is also a matter of concern. Conducting laboratory tests almost always results in the continuous production of toxic waste, which can be a significant contributor to environmental pollution. Laboratory chemical waste is a major health and environmental hazard. It can cause irreversible damage to the personnel and the environment in which it is released if not disposed of properly [1,2]. While some risks and hazards are easy to measure, finding the best way to indicate those risks and hazards could be a challenge. Unsafe waste disposal in laboratories endangers not just the human population but also native species and ecosystems. Aquatic life, animals, and agricultural irrigation systems are especially exposed to the risks and challenges caused by groundwater, water streams, and river contamination [1,2].This is especially true in the event of extended exposure to mixed organic and inorganic agents.

Human health is affected when laboratory waste containing potentially harmful compounds is released into the open environment without adequate treatment. Pollution is caused by organic and inorganic pollutants, heavy metals, and xenobiotic compounds, all of which contribute to a wide spectrum of illnesses and congenital malformations [1]. These contaminants are exceedingly harmful, and if they are allowed to build, there is a genuine chance that the local biosphere will be destroyed by chemical poisoning. This issue is not being addressed well in some countries with inadequate sanitation. Considering this, healthcare facilities must prioritize the safe disposal of chemical agents and have correct protocols in place to prevent the discharge of waste into the environment [1,2]. Considering this, sufficient care must be taken during the use and disposal of all laboratory agents to avoid adverse effects on human health and the environment. In the following section, the adverse effects of some of the common lab chemicals are addressed in detail.

2. Important Laboratory Chemicals with Proven Toxicity

2.1. Methanol

Methanol is an important laboratory reagent, and its adverse effects when inhaled have been examined in laboratory animals. Methanol and its metabolite formate were investigated in laboratory mice, and the results indicate that excessive levels in the blood can be neurotoxic [3]. The accumulation of formate or exposure to significantly elevated levels of formate can influence metabolic pathways. The most important pathway affected is the folate pathway, which plays a crucial role in the metabolic process, facilitating the transfer of one-carbon units essential for the production of nucleotides, amino acids, and other important molecules [3]. Methanol poisoning is also connected to retrolaminar demyelinating optic neuropathy, leading to blindness [4]. Additionally, formic acid accumulation leads to metabolic acidosis and blindness in humans and monkeys, indicating that the toxic effects are across the range of primates and therefore biologically important [5].

2.2. Acetone

Acetone is an important agent in histopathology. On the downside, inhalation of its vapors has been found to have detrimental effects on the respiratory system. Furthermore, it has been found to elicit irritation in the eye and at the site of contact. An increase in acetone inhalation can potentially lead to a decrease in olfactory sensitivity and compromise an individual’s acuities [6,7].

2.3. Sulphides

Sulfides are a ubiquitous agent produced when sulfur reacts with another element [8]. Hydrogen sulfide (H₂S) is a common laboratory reagent. However, exposure to minute levels causes olfactory paralysis, kerato-conjunctivitis, and pulmonary edema [9].

2.4. Cyanides

Cyanide is one of the most toxic agents and elicits responses within seconds and death within minutes. Cyanides have been found in laboratory waste and eventually find their way into water systems, where they contribute to contamination and affect human health [10]. Chemically, cyanide causes suffocation due to its action on cytochrome oxidase, the enzyme responsible for cellular respiration. Cyanide poisoning has been linked to animal deaths and is assumed to be the principal cause of toxic ataxic neuropathy in humans [11]. Furthermore, this carcinogenic substance produced thyroid gland growth and aberrant hormone synthesis [12]. Given all these ill effects and toxic effects at very low concentrations, it is important to adopt safe practices while handling and disposing of cyanides in laboratories.

2.5. Formaldehyde

Formalin, synthesized by dissolving formaldehyde gas in water, is a common fixative used to preserve tissues and cadavers for scientific study in pathology and anatomy laboratories across the world. People working in these laboratories are invariably at risk of being exposed to formalin, and this irritates the eyes, nose, and skin and causes a burning sensation in the throat. Additionally, long-term exposure to formalin has been linked to contact dermatitis, bronchitis, asthma, pneumonia, and other lung diseases [13,14,15,16,17]. Prolonged exposure also causes extensive lymphocytic infiltrations around the lung alveoli and bronchioles and triggers inflammation via reactive cell accumulation in the cerebral cortex [17]. Importantly, concerns have been raised about the development of birth defects [14]. Additionally, studies have linked formaldehyde to mutagenic properties and carcinogenic risk in humans, indicating that great caution needs to be adopted while handling it [15,16].

2.6. Ethanol

Ethanol (a principal laboratory solvent), when inhaled, bypasses the liver and enters the brain and bloodstream rapidly. On inhalation, ethanol affects the brain and other vital organs in the animal models of studies. Biochemically, alcohol vapor affects dopamine, GABA, glutamate, and corticotropin-releasing factors [18,19], while intermittent exposure causes damage to the liver, lungs, and cardiac system in laboratory mice [20].

2.7. Trichloroacetic Acid

Trichloroacetic acid (TCA) is a member of the chloroacetic acid group and was originally used as an herbicide. It is an essential laboratory agent used to precipitate proteins [21]. Subchronic exposure to TCA causes neurotoxicity, immunotoxicity, and hepatotoxicity in rodent models and should be handled with care as stipulated in safety manuals [22,23].

2.8. Benzene

Benzene is a carcinogen and myelotoxic agent, and its exposure for extended periods has been linked to the development of aplastic anemia, leukemia, and multiple myeloma [24]. Mechanistic studies indicate that the cytochrome P450 multifunctional oxygenase system is the primary regulator of liver metabolism, and the phenolic metabolites produced trigger hematotoxicity by interfering with cell division throughdamaging chromosomes, sister chromatid exchange, topoisomerase II, and mitotic spindles [25]. Benzene and its metabolites are harmful to the liver, kidneys, lungs, heart, and brain; theytrigger the formation of free radicals and damage vital molecules [25].

2.9. Xylene

Xylene is a common solvent used in tissue processing, staining, and cover sliding in histology laboratories. It has a high solubility factor and allows tissue transparency, simple paraffin penetration, and superior dewaxing and cleaning properties [26]. Most histopathology technicians are exposed to xylene during work through inhalation, ingestion, ocular, and skin contact [27]. The common symptoms of xylene vapor poisoning include headaches, dizziness, nausea, and regurgitation. Xylene exposure results in pulmonary edema when inhaled and can also contaminate the breast milk of a lactating mother [28].

2.10. Toluene

Toluene is an important laboratory agent, and its inhalation affects the neurological, circulatory, hepatic, cardiac, and renal systems [29]. Worse, maternal exposure to toluene during the gestational period has likewise been linked to adverse outcomes for newborns and has been associated with adverse outcomes such as premature birth, birth abnormalities, and impaired mental and physical development in children [29].

2.11. Chloroform

Chloroform is chemically highly transformative and quickly transits from a liquid into a gaseous state. It is highly toxic, and laboratory workers are exposed to it from inhalation or ingestion. Chloroform has harmful effects on the skin, eyes, liver, kidneys, and the neurological system. Studies have proved that chloroform breakdown generates free radicals, initiating carcinogenesis and damage to vital organs like the liver, kidneys, and brain in the affected individual [30].

2.12. Ammonia

Ammonia is a colorless gas and has a very unpleasant odor. Inhaling it can lead to several adverse health effects, such as reduced lung function, pathological changes in other organs, impaired nerve transmission, and an increase in lung infections [31]. The acidic and irritating characteristics of ammonia in high concentrations make it a serious health hazard, and when exposed to it for an extended period, humans can suffer chemical burns in the nasopharynx and trachea, obstruction of the airways, and respiratory distress, as well as edema of the bronchioles and alveoli [31].

2.13. Picric Acid

In histopathology studies, picric acid is a crucial tissue fixative and has been extensively utilized globally for many years. However, on the downside, picric acid causes skin and hair discoloration as well as eye irritation. Long-term exposure to this chemical causes dermatitis and damages the liver and kidneys. Some of the systemic poisoning symptoms noticed in people who have swallowed picric acid include headaches, dizziness, nausea, vomiting, and diarrhea, suggesting that the utmost care must be taken while handling this toxic agent [32].

2.14. Stains and Dyes

Dyes are a type of organic chemical colorant that bind to specific cellular components, making it easy to highlight areas of tissue and the organelle of choice during microscopic investigations [33,34,35,36,37]. Some of the important stains commonly used in medical laboratories include alcian blue, periodic acid–Schiff, Sudan black, Sudan III, Sudan IV, and oil red O [36]. Most of the Sudan dyes have been reported to cause a range of problems when inhaled or absorbed through the skin [37]. The other important class are nuclear stains (like ethidium bromide and acridine orange) that specifically bind to DNA. These stains are carcinogenic and must be handled with great care and disposed of in an eco-friendly way [38,39]. Studies have demonstrated that gentian violet, crystal violet, methyl violet, and malachite green stains interact with the DNA of live cells, are harmful, and should be handled with care [38,39,40].

3. Environmental Ethics and Medical Laboratory Sciences

Environmental ethics focuses on the philosophical underpinnings of environmental values and resulting practical concerns regarding social attitudes, behaviors, and policies that deal with the preservation and maintenance of ecological systems and biodiversity [41,42,43]. Medical sciences utilize a vast spectrum of reagents and chemicals for diagnostic and therapeutic purposes. During the research and development of all reagents, calibration, and instrumentations, vast amounts of biologically harmful waste are produced, which demands attention from various industrial regulatory bodies and pollution control agencies [43].

4. Environmental Ethics and UDBHR

Environmental ethics is a key area of interest globally and is important in all realms of science. The General Conference of UNESCO in October 2005 adopted by acclamation the Universal Declaration on Bioethics and Human Rights (UDBHR) [44], which deals with “ethical issues raised by medicine, life sciences, and associated technologies as applied to human beings”, and “anchors the principles it endorses in the rules that govern respect for human dignity, human rights and fundamental freedoms” [45,46,47]. Article 17 of UDBHR refers to “Protection of the environment, the biosphere, and biodiversity” and states that “due regard is to be given to the interconnection between human beings and other forms of life, to the importance of appropriate access and utilization of biological and genetic resources, to respect for traditional knowledge and to the role of human beings in the protection of the environment, the biosphere and biodiversity” [47].

Further, Article 14 on “Social responsibility and health” pertains to “access to adequate nutrition and water (Section 2b), and improvement of living conditions and the environment” (Section 2c) [45,46,47]. Article 16 on “Protecting future generations” reflects that “the impact of life sciences on future generations, including on their genetic constitution, should be given due regard”; this statement is grounded in the principles of preserving our environment. The implementation of these articles at the level of affiliated nations and states is explained in Article 22 on the “role of states in item 1; States should take all appropriate measures, whether of a legislative, administrative, or other character, to give effect to the principles set out in this Declaration in accordance with international human rights law. Such measures should be supported by action in the spheres of education, training and public information” [45,46,47].

The irresponsible disposal of laboratory waste could result in itsentry into water bodies, thereby exposing drinking water to excessive levels of hazardous compounds and organisms. Laboratory waste producingwater contamination is a possible problem that requires dedicated efforts to reduce or eliminate entirely [1]. UDBHR gives us a framework within which to work and identifies the scope of training and action plans to safeguard environmental values and preserve ethics while upholding human rights applicable to all. National guidelines provided byprofessional bodies and implementation through governmental agencies are key routes through which healthcare services and industries can work in harmony with nature and are mandatory.

5. Medical Laboratory Ethics

Medical ethics is a subfield of bioethics [48], and the four principles of autonomy, beneficence, non-maleficence, and justice also form the cornerstone of laboratory ethics [49]. All laboratories must follow the most recent legislation regarding patients’ rights, welfare, and comfort [50]. Medical establishments ought to safeguard the well-being of healthcare workers in the workplace, the general public, and the environment at large by decreasing the discharge of this perilous laboratory waste. This is applicable in healthcare sectors utilizing life sciences technologies, hospital services, and any direct or indirect domains wherein a human–environmental interface is expected. Understanding the inseparable reciprocity between both (which led to our current global regulatory guidelines) is a must, per the requirements.

6. Dos and Don’ts

6.1. Minimization of Waste Materials

On a practical note, it is likely that the negative effects of these laboratory reagents range from somewhat insignificant to exceedingly deadly. The amount of time a person isexposed to the toxicant is the most crucial consideration in making these kinds of decisions. In line with this, efforts to minimize exposure and waste are becoming more prevalent in healthcare facilities in their entirety. These methodologies enable cost savings, optimize resource utilization, and mitigate the environmental impact associated with the release of biohazard agents. Familiarity with the appropriate disposal methods for laboratory waste is a crucial subject that should be well understood by laboratory workers and other personnel working in the clinical laboratory settings. The ethical considerations surrounding environmental health research including human volunteers have garnered significant attention in recent years and need to be adhered to [51].

6.2. Measures to Be Adopted to Protect Personnel and Reduce Waste Production

Eliminating pollution from medical laboratories should be the ultimate goal of any establishment and labor work. It is imperative that the quantity of hazardous waste laboratories discharge into the environment is drastically reduced, and some of the important points to be adopted are as follows.

• Researchers should adopt a zero-waste philosophy and receive the necessary training to implement it in the laboratory.
• Waste can be reduced at any stage by employing sound waste management practices, like updating obsolete equipment and recycling and reusing whenever possible.
• The separation of waste into hazardous and non-hazardous categories is effective in preventing incidental contamination of the waste category.
• Staff should keep a record of the date of all laboratory substances on a daily basis and meticulously audit them at regular intervals in accordance with good laboratory practice.
• We should reduce excess procurement and utilization of potentially hazardous biological substances.
• We should avoidthe use of heavy metals such as lead, chromium, nickel, and arsenic, or use only minuscule amounts when obligatory for laboratory use.
• We should abstain from pouring chemicals down the drain, as this can contaminate the sewage system or discharge them into water sources that support the community and biosphere.
• We should avoid wasting reagents and other laboratory compounds through judicious planning and correct need-based calculations of the materials necessary for the day’s assays.
• Reusing and recycling chemicals is an effective method for reducing waste and maintaining clean laboratories [52].
• Staff should use a high-quality chemical hood while working with evaporating reagents (like xylene, chloroform, etc.) to minimize exposure.
• We should implement and adhere to quality and competence in facility controls, storage facilities, hazardous waste management, and records through meticulous daily auditing of chemical waste and its disposal in accordance with World Health Organization guidelines [1] and nodal agencies and centers like The Occupational Safety and Health Administration (OSHA).

While employing the approved laboratory reagents and chemicals, it is mandatory that both clinicians and laboratory personnel must be trained to understand how their day-to-day activities or actions could possibly impact the health of workers and the environment, and personal must learn howto lessen the burden of chemical waste. This is because results have shown that when handled and disposed of properly, dangerous substances can be utilized safely without compromising human health or the environment.

7. Conclusions

Awareness of the significance of ethical considerations is a crucial aspect of professionalism in the modern world. There is a lot of pressure on the field of laboratory medicine and research to adhere to and maintain high ethical standards, much like in other areas of clinical medicine [53]. Therefore, it is crucial to give laboratory staff enough education, increase their level of knowledge, and train them at repeated intervals to improve their working skills and awareness. Having an understanding of and sensitivity to these issues is crucial for ethical conduct in a laboratory setting. The most common issues with clinical use and waste generated include a lack of understanding of the health dangers involved, insufficient training in proper management and disposal systems, insufficient financial and human resources, a lack of priority given to theseissues, and neglect. Furthermore, regardless of the size or location of the healthcare facility, all personnel should be aware of the environmental implications of biomedical waste.

It is highly recommended that the laboratory establishment should implement the guidelines set forth by “International Organisation for Standardisation(ISO), World Health Organization (WHO), Clinical and Laboratory Standards Institute (CLSI), The Occupational Safety and Health Administration (OSHA), National Research Council Recommendations, National Institute for Occupational Safety and Health (NIOSH), U.S. Environmental Protection Agency (EPA), National Institute for Occupational Safety and Health (NIOSH), Occupational Safety and Health Guidance Manual for Hazardous Waste Site Activities, National Accreditation Board for Hospitals & Healthcare Providers (NABH), National Accreditation Board for Testing and Calibration Laboratories (NABL)” guidelines as mandated by the rule of the land and the country.

Irrespective of the size of the laboratory and the country, standards clearly mention the need to maintain a safe working environment in the medical testing laboratory and the need to store and handle chemicals as per their hazard category in accordance with WHO guidelines [1]. On a closing note, the laboratory and environmental impact of the actions of human beings and their implications for ecosystems and other wild species further hold us responsible for current and future generations of our species as custodians of what we inherited from our forefathers. While we prioritize our potential growth and development, the medical sciences are often considered key non-negotiable domains; however, the ethical dimension of our environmental impact seldom receives sufficient attention.