Littered cigarette butts as a source of nicotine in urban waters

Abstract

• Butts are heterogeneously distributed, mean of 2.7 m −2 , max of 48 m −2 in study area. • Quick nicotine elution from butts in standing and rainwater. • Cigarette butts are hazardous waste according to EU thresholds. • Cigarette butts represent a threat to urban water quality and drinking water. • Recommendation of public education campaign to reduce littered butts. The effect of nicotine from littered cigarette butts on the quality of urban water resources has yet to be investigated. This two-part study addresses the spatial variation, seasonal dynamics and average residence time of littered cigarette butts in public space, as well as the release of nicotine from cigarette butts to run-off in urban areas during its residence time. Thereby, we tested two typical situations: release to standing water in a puddle and release during alternating rainfall and drying. The study took place in Berlin, Germany, a city which completely relies on its own water resources to meet its drinking water demand. Nine typical sites located in a central district, each divided into 20 plots were studied during five sampling periods between May 2012 and February 2013. The nicotine release from standardized cigarette butts prepared with a smoking machine was examined in batch and rainfall experiments. Littered cigarette butts are unevenly distributed among both sites and plots. The average butt concentration was 2.7 m −2 (SD = 0.6 m −2 , N = 862); the maximum plot concentration was 48.8 butts m −2 . This heterogeneity is caused by preferential littering (gastronomy, entrances, bus stops), redistribution processes such as litter removal (gastronomy, shop owners), and the increased accumulation in plots protected from mechanized street sweeping (tree pits, bicycle stands). No significant seasonal variation of cigarette butt accumulation was observed. On average, cigarette butt accumulation is characterized by a 6 days cadence due to the rhythm and effectiveness of street sweeping (mean weekly butt accumulation rate = 0.18 m −2 d −1 ; SD = 0.15 m −1 ). Once the butt is exposed to standing water, elution of nicotine occurs rapidly. Standardized butts released 7.3 mg g −1 nicotine in a batch experiment (equivalent to 2.5 mg L −1 ), 50% of which occurred within the first 27 min. In the rainfall experiment, the cumulative nicotine release from fifteen consecutive precipitation events (each 1.4 mm) was 3.8 mg g −1 , with 47% during the first event. According to these results, one cigarette butt may contaminate an amount of 1000 L water to concentrations above the predicted no effect concentration (PNEC) of only 2.4 × 10 −3 mg L −1 (Valcárcel et al., 2011). Given the continuous littering of cigarette butts, and the rapid release of nicotine, cigarette butts are assessed to be a relevant threat to the quality of urban waters and consequently to drinking water.