Chemical compounds with environmental impact

The use of chemical compounds is deeply embedded in modern society, driving advancements in agriculture, medicine, and industry. However, the widespread and often indiscriminate use of chemicals, while beneficial for their intended applications, has led to significant environmental consequences (Fig. 1 [1]). Agrochemicals, veterinary drugs, and various industrial toxins are particularly scrutinized for their roles in environmental pollution. In addition, the pharmaceutical industry, through the processes of drug discovery and production, also poses substantial environmental challenges.

Fig. 1. Examples of chemical impacts on the environment, from [1].

Agrochemicals are a cornerstone of modern agriculture, encompassing a range of products designed to enhance crop production and protect against pests and diseases [2-3]. These include pesticides (herbicides, fungicides, insecticides, etc.) and fertilizers. Glyphosate—a non-selective herbicide—is one of the most widely used and is credited with revolutionizing weed control in agriculture. Neonicotinoids, a class of insecticides, have also gained prominence due to their effectiveness against a broad spectrum of insect pests [4].

While agrochemicals have undoubtedly boosted agricultural productivity, their environmental costs are significant [5-6]. The widespread use of pesticides has been linked to the decline of non-target species, such as bees and other pollinators, which are crucial for maintaining biodiversity and food security. Neonicotinoids, in particular, have been implicated in bee colony collapse and/or disorder, leading to severe disruptions in pollination services.

Agrochemicals can also cause soil degradation, as the repeated application of these chemicals can alter soil microbial communities, reducing soil fertility over time. The runoff of fertilizers and pesticides into water bodies contributes to water contamination. Persistent agrochemicals, such as organochlorines, have the ability to bioaccumulate in the food chain, posing long-term risks to both wildlife and human health.

Veterinary drugs play a vital role in animal husbandry, ensuring the health and productivity of livestock. These drugs include antibiotics, antiparasitics, hormones, and vaccines. Antibiotics like tetracyclines and sulfonamides are commonly used to treat bacterial infections, while antiparasitics such as ivermectin are used to control internal and external parasites. Hormones, including growth promoters and reproductive hormones, are also widely used in livestock to enhance productivity.

The environmental impact of veterinary drugs [7,8] arises primarily from their excretion by treated animals. A significant portion of these drugs is not metabolized. It is excreted in active forms, enters the environment and contaminates soil and water with pharmaceutical residues. In aquatic environments, veterinary drugs can adversely affect non-target species. Hormones like estrogen can disrupt the endocrine systems of aquatic organisms, bringing about reproductive abnormalities and population declines in fish and amphibians. One of the most concerning impacts of hormones is the development of antibiotic-resistant bacteria which is the case with the widespread use of antibiotics in livestock, often at sub-therapeutic levels for growth promotion.These resistant bacteria can be transferred to humans through direct contact, consumption of animal products, or environmental pathways, posing a significant public health threat.

Industrial activities are a major source of environmental toxins, including heavy metals, persistent organic pollutants (POPs), and various chemical by-products. Heavy metals, e.g., mercury, lead, cadmium, and arsenic are naturally occurring elements exacerbated in the environment by industrial processes, such as mining, smelting and waste incineration. POPs, including dioxins, polychlorinated biphenyls, and certain pesticides, are organic compounds that resist environmental degradation and persist in the environment for long periods.

Heavy metals pose severe risks to environmental and human health due to their toxicity, persistence, and ability to bioaccumulate in organisms. Mercury, in particular, is released into the atmosphere from coal combustion and later deposited into water bodies, where it is transformed into methylmercury. This potent neurotoxin bioaccumulates in fish and shellfish. Human exposure to methylmercury occurs primarily through the consumption of contaminated fish, leading to serious health issues, like neurological disorders and developmental delays in children.

POPs, on the other hand, are known for their ability to travel long distances through air and water, leading to widespread environmental contamination. These compounds can bioaccumulate in the fat tissue of living organisms and travel through the food chain, resulting in higher concentrations in top predators, including humans. POPs have been linked to a range of adverse health effects, including cancer, reproductive disorders, and endocrine disruption.

The pharmaceutical industry is a major contributor to environmental pollution, particularly during the drug discovery and development phases [11-13]. The process of drug discovery involves the synthesis and testing of numerous chemical entities, many of which have substantial environmental footprints. The use of various solvents, reagents and catalysts in chemical synthesis can result in the generation of hazardous waste. Additionally, the production of active pharmaceutical ingredients often involves complex chemical processes that can release pollutants into the air, water, and soil.

One of the key environmental concerns in drug discovery is the use of solvents, which are essential for many chemical reactions. Solvents account for a significant portion of the waste generated in pharmaceutical manufacturing. Many commonly used solvents, such as dichloromethane and toluene, are volatile organic compounds that contribute to air pollution and pose risks to human health. The improper disposal of solvent waste can lead to soil and water contamination, further exacerbating environmental degradation.

Next, pharmaceutical waste is a significant environmental issue, originating from various sources, including manufacturing facilities, healthcare institutions, and households. Improper disposal of unused or expired medications is common, leading to the contamination of aquatic ecosystems. Pharmaceuticals enter the environment through wastewater treatment plants, often not equipped to remove all medicine residues being discharged into rivers, lakes, and oceans. Many drugs are designed to be biologically active at low concentrations, and their presence in the environment can profoundly affect non-target organisms. For example, the presence of antidepressants like fluoxetine in rivers is linked to altered behavior and reproductive outcomes in fish.

Moving forward, the development of new chemical entities (NCEs) is a cornerstone of pharmaceutical innovation, offering the potential to treat previously untreatable diseases. However, the environmental impact of NCEs is often not fully understood before they are released into the market. Many NCEs have unique chemical structures that may not be easily degraded by natural processes, leading to their persistence in the environment [1].

As a potential solution, designing greener active pharmaceutical ingredients [14-16] aims to reduce or eliminate the application and generation of hazardous substances and minimize the environmental impact of drug production. This includes the use of safer solvents, the development of catalytic reactions that reduce waste, and the use of renewable feedstocks. Integrating green chemistry principles into the pharmaceutical industry holds great promise for lowering the environmental impact of drug production while maintaining the high standards of safety and efficacy required for new medicines.

Keeping the focus on the research needs for applications and environmental safety, Life Chemicals has designed its proprietary collections of Screening Compound Libraries, including:

• AgroChemical Screening Libraries
• Veterinary Focused Screening Library

In order to diversify and expand your research toolbox, we also offer a number of related screening libraries:

• Natural Product-like Compound Libraries
• Biologically Active Compound Library

Order your custom compound selections and enjoy the most convenient terms and competitive pricing.

Please, contact us at marketing@lifechemicals.com for any additional information and price quotations.

Download SD files with compound structures directly from our Downloads section

References

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2. Tudi, M., Daniel Ruan, H., Wang, L., et al. (2021). Agriculture development, pesticide application and its impact on the environment. Int. J. Environ. Res. Public Health, 18(3), 1112. DOI: 10.3390/ijerph18031112
3. Pathak, V. M., Verma, V. K., Rawat, B. S., et al. (2022). Current status of pesticide effects on environment, human health and its eco-friendly management as bioremediation: A comprehensive review. Front. Microbiol., 13, 962619. DOI: 10.3389/fmicb.2022.962619
4. Morrissey, C. A., Mineau, P., Devries, J. H., Sanchez-Bayo, F., et al. (2015). Neonicotinoid contamination of global surface waters and associated risk to aquatic invertebrates: A review. Environment International, 74, 291-303. DOI: 10.1016/j.envint.2014.10.024
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7. Boxall, A. B. A., Fogg, L. A., et al. (2004). Veterinary medicines in the environment. In: Reviews of Environmental Contamination and Toxicology, 180, 1-91.Springer, New York, NY. DOI: 10.1007/0-387-21729-0_1
8. Boxall, A. B. A. (2010). Veterinary Medicines and the Environment. In: Cunningham, F., Elliott, J., Lees, P. (eds) Comparative and Veterinary Pharmacology. Handbook of Experimental Pharmacology, vol 199. Springer, Berlin, Heidelberg. DOI: 10.1007/978-3-642-10324-7_12
9. Shen, J., Yang, L., Liu, G., Zhao, X., & Zheng, M. (2021). Occurrence, profiles, and control of unintentional POPs in the steelmaking industry: A review. Science of the Total Environment, 773, 145692. DOI: 10.1016/j.scitotenv.2021.145692
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14. Wynendaele, E., Furman, C., Wielgomas, B., et al. (2021). Sustainability in drug discovery. Medicine in Drug Discovery, 12, 100107. DOI: 10.1016/j.medidd.2021.100107
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16. Sheldon, R. A. (2016). Green chemistry and resource efficiency: Towards a green economy. Green Chemistry, 18(11), 3170-3183. DOI: 10.1039/C6GC90040B