Heavy metal and metalloid contamination of nectar: Sources, ecological implications, and methods of analysis

Abstract

Pollination is among the most vital interactions in terrestrial ecosystems, yet it is increasingly under threat. One emerging concern is the contamination of nectar, the primary floral reward, with heavy metals and metalloids. Unlike other floral tissues, insect bodies, or bee products such as honey, nectar constitutes a distinct exposure route as it is a directly consumed, chemically dynamic resource that mediates immediate interactions between plants and floral visitors. Despite its potential ecological significance, research on how such pollution affects plants, pollinators, and their interactions remains scarce. Understanding these processes is crucial for developing effective strategies to protect wildlife, ensure stable crop production, and safeguard both environmental and human health. In this review, we synthesize current knowledge on nectar contamination by heavy metals and metalloids, assessing their impacts on plants, pollinators, and pollination itself. We evaluate the methods used to detect and analyze nectar contamination, examine available data, and consider the ecological and evolutionary implications. By highlighting key gaps and offering new insights, we aim to advance this emerging field and guide future research on pollination in polluted environments.