Data from: How common road salts and organic additives alter freshwater food webs: in search of safer alternatives

The application of deicing road salts began in the 1940s and has increased drastically in regions where snow and ice removal is critical for transportation safety. The most commonly applied road salt is sodium chloride (NaCl). However, the increased costs of NaCl, its negative effects on human health, and the degradation of roadside habitats has driven transportation agencies to seek alternative road salts and organic additives to reduce the application rate of NaCl or increase its effectiveness. Few studies have examined the effects of NaCl in aquatic ecosystems, but none have explored the potential impacts of road salt alternatives or additives on aquatic food webs. We assessed the effects of three road salts (NaCl, MgCl2 and ClearLane™) and two road salts mixed with organic additives (GeoMelt™ and Magic Salt™) on food webs in experimental aquatic communities, with environmentally relevant concentrations, standardized by chloride concentration. We found that NaCl had few effects on aquatic communities. However, the microbial breakdown of organic additives initially reduced dissolved oxygen. Additionally, microbial activity likely transformed unusable phosphorus from the organic additives to usable phosphorus for algae, which increased algal growth. The increase in algal growth led to an increase in zooplankton abundance. Finally, MgCl2 – a common alternative to NaCl – reduced compositional differences of zooplankton, and at low concentrations increased the abundance of amphipods. Synthesis and applications. Our results indicate that alternative road salts (to NaCl), and road salt additives can alter the abundance and composition of organisms in freshwater food webs at multiple trophic levels, even at low concentrations. Consequently, road salt alternatives and additives might alter ecosystem function and ecosystem services. Therefore, transportation agencies should use caution in applying road salt alternatives and additives. A comprehensive investigation of road salt alternatives and road salt additives should be conducted before wide-scale use is implemented. Further research is also needed to determine the impacts of salt additives and alternatives on higher trophic levels, such as amphibians and fish.道路除冰盐的应用始于20世纪40年代，在除雪除冰对道路交通安全至关重要的地区，其使用量大幅增长。当前最常用的道路盐为氯化钠（sodium chloride，NaCl）。然而，氯化钠的使用成本持续攀升、对人体健康存在负面影响，且会造成路边生境退化，这促使交通管理部门寻求替代道路盐与有机添加剂，以降低氯化钠的施用量或提升其除冰效能。目前鲜有研究探讨氯化钠对水生生态系统的影响，且尚无研究探索道路盐替代品或添加剂对水生食物网的潜在影响。 本研究以经氯离子浓度标准化的环境相关浓度构建实验水生群落，评估了三种道路盐（氯化钠、氯化镁（magnesium chloride，MgCl₂）与ClearLane™）以及两种混有有机添加剂的道路盐（GeoMelt™与Magic Salt™）对水生食物网的影响。研究发现，氯化钠对水生群落的影响微弱。但有机添加剂的微生物降解过程会在初期降低水体溶解氧水平。此外，微生物活动可将有机添加剂中难被利用的磷转化为藻类可利用的有效磷，进而促进藻类增殖。藻类增殖进而带动浮游动物丰度上升。最后，作为氯化钠常见替代品的氯化镁会降低浮游动物的群落组成差异，且在低浓度下可提升端足类动物的丰度。 综合与应用。本研究结果表明，作为氯化钠替代品的道路盐及道路盐添加剂，即便在低浓度下，也可改变淡水食物网多个营养级的生物丰度与群落组成。因此，道路盐替代品与添加剂可能会改变生态系统功能与生态系统服务。故此，交通管理部门在使用道路盐替代品与添加剂时应保持谨慎。在大规模推广应用前，需对道路盐替代品与添加剂开展全面调查。此外，还需开展进一步研究，以明确盐类添加剂与替代品对两栖动物、鱼类等更高营养级生物的影响。