Regulatory challenges in managing emerging contaminants (ECs): a global review perspective scientific barriers, policy response, and future directions

Abstract Emerging contaminants (ECs) comprise a diverse group of synthetic and naturally occurring chemicals that are not routinely monitored but are increasingly recognized for their potential risks to ecosystems and human health. Many ECs, such as pharmaceuticals, personal care products, endocrine-disrupting compounds, pesticides, nanomaterials, and industrial chemicals, are biologically active, environmentally persistent, and mobile, enabling them to exert toxicological effects even at ultra-trace concentrations. Their widespread occurrence in freshwater, marine environments, and drinking water sources reflects the limitations of conventional treatment systems and underscores the urgency of improved regulatory oversight. ECs enter the environment through multiple pathways, including wastewater effluent, agricultural runoff, urban stormwater, and improper disposal, subsequently dispersing across environmental compartments where they may bioaccumulate and disrupt biological processes. Evidence links EC exposure to endocrine disruption, developmental toxicity, antimicrobial resistance, and compromised ecological integrity, yet many remain undetected under existing monitoring frameworks. These challenges highlight the need for advanced analytical methods, standardized detection protocols, and robust risk assessment approaches to support effective governance. This review evaluates the global regulatory landscape for ECs, tracing policy developments from the 1970s to 2025 across major jurisdictions. By comparing regulatory approaches, action levels, and institutional responses, the paper identifies critical gaps, including inconsistent definitions, absence of enforceable thresholds, limited monitoring coverage, and slow adaptation of legacy water quality standards. The review emphasizes the growing relevance of group-based regulation, precautionary and adaptive management, and harmonized international monitoring frameworks. Collectively, this analysis provides an integrated perspective on how science, policy, and governance must evolve to address the complex, cross-border challenges posed by ECs.