Bonanomi Giuliano, Incerti Guido, Cesarano Gaspare, Gaglione Salvatore A, Lanzotti Virginia
Dipartimento di Agraria, University of Naples Federico II, via Università 100, Portici (NA), Italy.
PLoS One. 2015 Jan 27;10(1):e0117393. doi: 10.1371/journal.pone.0117393. eCollection 2015.
Cigarette butts (CBs) are the most common type of litter on earth, with an estimated 4.5 trillion discarded annually. Apart from being unsightly, CBs pose a serious threat to living organisms and ecosystem health when discarded in the environment because they are toxic to microbes, insects, fish and mammals. In spite of the CB toxic hazard, no studies have addressed the effects of environmental conditions on CB decomposition rate. In this study we investigate the interactive effects of substrate fertility and N transfer dynamics on CB decomposition rate and carbon quality changes. We carried out an experiment using smoked CBs and wood sticks, used as a slow decomposing standard organic substrate, incubated in both laboratory and field conditions for two years. CB carbon quality changes during decomposition was assessed by 13C CPMAS NMR. Our experiment confirmed the low degradation rate of CBs which, on average, lost only 37.8% of their initial mass after two years of decomposition. Although a net N transfer occurred from soil to CBs, contrary to our hypothesis, mass loss in the medium-term (two years) was unaffected by N availability in the surrounding substrate. The opposite held for wood sticks, in agreement with the model that N-rich substrates promote the decomposition of other N-poor natural organic materials with a high C/N ratio. As regards CB chemical quality, after two years of decomposition 13C NMR spectroscopy highlighted very small changes in C quality that are likely to reflect a limited microbial attack.
烟头是地球上最常见的垃圾类型，据估计每年有4.5万亿个被丢弃。除了有碍观瞻外，烟头丢弃在环境中时会对生物和生态系统健康构成严重威胁，因为它们对微生物、昆虫、鱼类和哺乳动物有毒。尽管烟头存在有毒危害，但尚无研究探讨环境条件对烟头分解速率的影响。在本研究中，我们调查了底物肥力和氮转移动态对烟头分解速率和碳质量变化的交互作用。我们使用烟熏烟头和木棍进行了一项实验，木棍用作缓慢分解的标准有机底物，在实验室和田间条件下培养两年。通过13C交叉极化魔角旋转核磁共振（13C CPMAS NMR）评估分解过程中烟头的碳质量变化。我们的实验证实了烟头的低降解率，经过两年分解后，烟头平均仅损失其初始质量的37.8%。尽管发生了从土壤到烟头的净氮转移，但与我们的假设相反，中期（两年）的质量损失不受周围底物中氮有效性的影响。木棍的情况则相反，这与富含氮的底物促进其他碳氮比高的贫氮天然有机材料分解的模型一致。关于烟头的化学质量，经过两年分解后，13C NMR光谱突出显示碳质量的变化非常小，这可能反映了有限的微生物攻击。
