Gomes Megan, Ralph Timothy J, Humphries Marc S, Graves Bradley P, Kobayashi Tsuyoshi, Gore Damian B
School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa; School of Natural Sciences, Macquarie University, NSW, Australia.
School of Natural Sciences, Macquarie University, NSW, Australia.
Sci Total Environ. 2025 Jan 1;958:178084. doi: 10.1016/j.scitotenv.2024.178084. Epub 2024 Dec 13.
Waterborne contaminants pose a significant risk to water quality and plant health in agricultural systems. This is particularly the case for relatively small-scale but intensive agricultural operations such as plant production nurseries that often rely on recycled irrigation water. The increasing global demand for plants requires improved water quality and more certainty around water availability, which may be difficult to predict and deliver due to variable and changing climate regimes. Production nurseries are moving to adopt best management practices that recycle water; however, the risks associated with waterborne contaminants of various types, including nutrients, pesticides, plant pathogens, micro-plastics, and toxic metals, are not well understood. We review and synthesise the physical and biogeochemical factors that contribute to waterborne contaminant risk, and the main types of contaminants that are likely to require management, at plant production nurseries. Catchment characteristics (i.e., topography, land use), hydroclimatic factors (i.e., storms, floods, droughts), and landscape hydrological and sediment connectivity influence surface runoff, sediment transport, and associated contaminant transfer and storage. High hydrological connectivity can increase the risk of contaminant transport from the surrounding landscape to nurseries, with potential negative impacts to water quality in reservoirs and in turn plant health. High connectivity may also increase the risk of contaminants (e.g., sediment, pesticides, and phytopathogens) being transferred from nursery farms into downstream waterways, with consequences for aquatic ecosystems. Like all intensive agricultural operations, nurseries need to consider sources of irrigation water, water treatment and management strategies, and catchment and hydroclimatic factors, to mitigate the spread of contaminants and reduce their impacts on both plant production and the surrounding environment. Further research is needed to quantify contaminant loads and transfer pathways in these agricultural systems, and to better understand the threshold levels of contaminants that adversely affect plant health and which may result in devastating economic losses.
在农业系统中，水传播污染物对水质和植物健康构成重大风险。对于相对小规模但集约化的农业经营活动，如植物生产苗圃而言，情况尤其如此，这些苗圃通常依赖循环灌溉水。全球对植物的需求不断增加，这就需要改善水质，并更确定地保障水的供应，然而由于气候模式多变且不断变化，水的供应可能难以预测和实现。生产苗圃正转向采用循环用水的最佳管理做法；然而，人们对包括营养物质、农药、植物病原体、微塑料和有毒金属在内的各类水传播污染物所带来的风险尚未充分了解。我们回顾并综合了导致水传播污染物风险的物理和生物地球化学因素，以及植物生产苗圃中可能需要管理的主要污染物类型。集水区特征（即地形、土地利用）、水文气候因素（即风暴、洪水、干旱）以及景观水文和泥沙连通性会影响地表径流、泥沙输送以及相关污染物的转移和储存。高水文连通性会增加污染物从周边景观输送到苗圃的风险，对水库水质进而对植物健康产生潜在负面影响。高连通性还可能增加污染物（如泥沙、农药和植物病原体）从苗圃农场转移到下游水道的风险，从而对水生生态系统造成影响。与所有集约化农业经营活动一样，苗圃需要考虑灌溉水源、水处理和管理策略以及集水区和水文气候因素，以减轻污染物的扩散并减少其对植物生产和周边环境的影响。需要进一步开展研究，以量化这些农业系统中的污染物负荷和转移途径，并更好地了解对植物健康产生不利影响且可能导致巨大经济损失的污染物阈值水平。
