Lubricants are substances introduced between two surfaces in relative motion to reduce friction, wear, and heat generation. In environmental chemistry, understanding lubricants is crucial because their chemical composition and degradation products can impact ecosystems, water quality, and soil health. Lubricants are typically composed of a base oil, which can be mineral, synthetic, or bio-based, and various additives that enhance specific properties such as anti-wear, antioxidant, and corrosion-inhibiting characteristics. The mechanism by which lubricants function is primarily based on the formation of a continuous film between contacting surfaces, preventing direct metal-to-metal contact and thereby minimizing mechanical wear. The mechanism of lubrication can be explained through three primary regimes: hydrodynamic, boundary, and mixed lubrication. Hydrodynamic lubrication occurs when a full fluid film separates the surfaces completely, typically at higher speeds and moderate loads. In this regime, the lubricant pressure within the film is sufficient to support the load, and friction is mainly due to the viscosity of the lubricant. Boundary lubrication, on the other hand, arises when the lubricant film is insufficient to fully separate the surfaces, often under high load or low-speed conditions. In this case, additives such as sulfur- or phosphorus-based compounds form protective chemical layers on the surfaces to reduce direct contact. Mixed lubrication combines aspects of both, where portions of the surfaces experience fluid film lubrication while other regions are in boundary contact, requiring the lubricant to simultaneously provide both hydrodynamic support and chemical protection. Lubricants can be classified based on their physical state, origin, or specific function. Physically, they can be liquids, greases, or solid lubricants. Liquid lubricants are the most common,