Cigarette butts are a prevalent form of litter containing numerous toxic chemicals. Because cigarette butts are frequently deposited on the ground and carried into water bodies, greater understanding of the toxic effects of cigarette butts in aquatic ecosystems is needed. We examined the toxicity of cigarette butts to algal growth and diatom health—especially pertinent because of the strong ecological role of these organisms. We modified the agar-based nutrient-diffusing substrate method by using cigarette butt leachate (at 10, 5, 2.5, and 1.25 butts/l concentrations), a whole cigarette butt, and a plain agar control. After incubating for 10 days in a small stream, the biofilms from the diffusing substrates were assessed for algal biomass and diatom health (chloroplast intactness and size of lipid bodies in two abundant species of Navicula). There were no significant differences among the cigarette butt treatments for algal biomass or diatom health; hence, evidence of toxic effects was not found. Other studies have demonstrated cigarette butt leachate toxicity to fish and aquatic invertebrates, but these studies were done in closed systems. In contrast, in open stream ecosystems, effluent may be quickly diluted and carried away by water flow, and the complex chemical environment of streams likely includes leachate from a variety of riparian leaves that fell into the stream (i.e., algae are naturally exposed to low concentrations of a wide variety of secondary chemicals). Our results do not preclude the finding of toxicity of cigarette butt effluent to algae, including diatoms, in standard toxicity tests.

烟蒂是一种普遍存在的垃圾形式，其中含有多种有毒化学物质。由于烟蒂经常沉积在地面上并被带入水体，因此需要更深入地了解烟蒂在水生生态系统中的毒性作用。我们研究了烟蒂对藻类生长和硅藻健康的毒性——尤其是这些生物具有很强的生态作用。我们通过使用烟蒂渗滤液（浓度为 10、5、2.5 和 1.25 烟蒂/升）、整个烟蒂和普通琼脂对照来改进基于琼脂的营养扩散基质方法。在小溪中孵育 10 天后，对来自扩散基质的生物膜的藻类生物量和硅藻健康（叶绿体完整性和两种丰富的藻类中脂质体的大小）进行了评估。舟形）。烟蒂处理对藻类生物量或硅藻健康没有显着差异；因此，没有发现毒性作用的证据。其他研究表明烟蒂渗滤液对鱼类和水生无脊椎动物具有毒性，但这些研究是在封闭系统中进行的。相比之下，在开阔的河流生态系统中，流出物可能会被水流迅速稀释并带走，而河流复杂的化学环境可能包括落入河流的各种河岸树叶的渗滤液（即藻类自然暴露于低各种二级化学品的浓度）。我们的结果并不排除在标准毒性测试中发现烟蒂流出物对藻类（包括硅藻）的毒性。