Paint particle pollution in aquatic environments: Current advances and analytical challenges

Paints, coatings and varnishes play a crucial role in various industries and daily applications, providing essential material protection and enhancing aesthetic characteristics. However, they sometimes present environmental challenges such as corrosion, wear, and biofouling which lead to economic losses and ecological harm. Paint particles (PPs), including antifouling/anticorrosive paint particles (APPs), originate from marine, industrial, and architectural activities, primarily due to paint leakage, wear, and removal, thus significantly contributing to marine pollution. These particles are often misclassified as microplastics (MPs) because of their polymeric content, so the abundance of these materials is often underestimated. Standardized assessment methodologies are imperative to accurately differentiate and quantify them. Since PPs/APPs incorporate hazardous substances like metals, biocides, and additives that leach into the environment, further investigation into their potential impacts on organisms is of utmost importance to understand their complex composition and toxicity. While essential characterization techniques are needed, a holistic approach, focusing on sustainable paint formulations, is crucial for effective pollution mitigation. This review delves into the intricate structure of paint systems, elucidating the mechanisms governing the aging and formation of PPs/APPs, their prevalence and subsequent environmental and ecotoxicological repercussions. Additionally, it addresses challenges in sampling, processing, and characterizing PPs/APPs, advocating standardized approaches to mitigate their environmental threats, and proposing new perspectives for the future.