Estimation of the heavy metals released from cigarette butts to beaches and urban environments

Alarming cigarette butts contamination on sandy beaches of East Java, Indonesia

Cigarette butts, along with other plastic items, have been extensively studied as the primary source of marine litter in coastal areas around the world. Although there has been extensive research on cigarette butts in coastal areas worldwide, there have been no publications related to this in coastal areas in Indonesia. Therefore, this research is the first to report on the pollution of cigarette butts on different Indonesian beaches, specifically in the East Java Province. The study aimed to assess the abundance, size distribution, and pollution levels associated with cigarette butts from 15 different beaches. Cigarette butts were collected using a 5 × 5 m quadrate transect, placed 20 m apart along the coastline from December 2022 to August 2023. The collected cigarette butts were counted and measured in three different sizes: 0.5-2.5 cm, 2.5-5 cm, and 5-10 cm. A total of 323 cigarette butts were collected, with densities ranging from 0.08 to 3.32 items m-2. The majority of butts were classified as meso-size (0.5-2.5 cm), suggesting incomplete smoking and a higher potential for toxin release. The Cigarette Butt Pollution Index (CBPI) revealed a spectrum of pollution levels, from low to severe, with most beaches exhibiting severe pollution. Factors such as negligent smoking behavior, inadequate waste management infrastructure, and beach environmental conditions were identified as key contributors to this pollution. This study highlights the urgent need for comprehensive strategies, including public awareness campaigns, improved waste management, and beach clean-ups, to mitigate the environmental impact of cigarette butt pollution on Indonesian beaches.

Negative effects of cigarette butt leachate on freshwater phytoplankton communities

We experimentally tested the effects of different concentrations of cigarette butt leachate on freshwater phytoplankton chlorophyll-a, species richness, cell density, and community composition. For this, we sampled the phytoplankton from a eutrophic lake and acclimated it for 24 h in microcosms. We then conducted the experiment in microcosms maintained for 96 h. The experiment consisted of four treatments: control and leachate from 1 butt L-1 (T1), 5 butts L-1 (T5), and 10 butts L-1 (T10), which were prepared by diluting a stock solution of leachate from 50 butts L-1. We found that algal chlorophyll-a content was not affected by different leachate concentrations. In contrast, phytoplankton cell density decreased in a dose-dependent manner as concentrations of the leachate increased. Similarly, the number of species was highest in the control group relative to all other treatments, with T1 and T5 showing higher species richness than T10. Additionally, the exposition to different concentrations of the leachate impacted community composition across all treatments in comparison to the control group. Our results suggest that cigarette butt leachate alters the number of cells and species, as well as the distribution of abundance, without necessarily reducing chlorophyll-a concentrations. Our findings indicate that to gain a comprehensive understanding of the effects of cigarette butt leachate on freshwater ecosystems, it is essential to evaluate more realistic scenarios that incorporate aquatic communities, rather than isolated species.

The effect of climatic variables and techno-structural factors on the water pollution caused by nicotine leakage from littered cigarette butts

Nicotine is one of the main pollutants in cigarette smoke that trapped in the filter. Nicotine leakage from cigarette butts is one of the concerns associated with this hazardous waste. In this study, the concentration of nicotine leaked from cigarette butts into the urban environment was investigated under the influence of three parameters including rainfall, density, and the durability of the littered cigarette butt. The leakage of nicotine into the environment was estimated in six scenarios based on the difference in the durability of cigarette butts in the urban environment and the humidity ratio. The results showed that the density of littered cigarette butts was 0.0019-0.294 number/m2. The density of littered cigarette butts in residential land-use was 52.38% lower than commercial land-use. Nicotine leakage from cigarette butts in commercial, residential, and recreational land-uses was 1.1, 0.484, and .0065 mg/m2, respectively. In the studied scenarios, in the best and worst case, 335,070 and 481,950 gr/year of nicotine will leak from the cigarette butt into the water resources. Considering that cigarette butts are a serious source of toxins including nicotine to the environment, control measures are necessary to reduce its density in the urban environment.

Study of the impact of structural factors and cleaning efficiency in reducing hazardous litter density and its related pollution in urban environment

Cigarette filter is the most common hazardous litter that contains many pollutants including PAHs. The durability of this litter in the urban environment has an important effect on the rate of pollutant leakage. In this study, the leakage rate of PAHs from the littered cigarette filters was estimated by considering the affecting parameters on their durability in the urban environment. The results showed that the density of littered cigarette filters in the studied locations was 0.00048-0.13563 g/m2. The maximum spatial variation of the littered cigarette filter was 225 times. The average leakage of the total studied PAHs was estimated to be 2.048 µg/10 m2. The impact of structural factors and efficiency of urban cleaning in the estimated leakage was at most 2.4 times. It is necessary to change the behavior of citizens in littering the cigarette filter, considering its durability in the urban environment, to reduce the environmental and health consequences caused by the leakage of PAHs.

Exploring cigarette butts pollution in Saint Martin Island: A marine protected area

Saint Martin Island (SMI), the only coral island in Bangladesh, is located in the Bay of Bengal and has been identified as a marine protected area (MPA). Littering cigarette butts (CBs) waste in an ecologically sensitive environment can have numerous adverse effects. The purpose of this research is to investigate the abundance and density of CBs in SMI and to assess the pollution status using the Cigarette Butt Pollution Index (CBPI). This study is conducted based on the visual survey method in the three types of land use zones of SMI. During the peak season, the investigation was carried out from 9 a.m. to 5 p.m. in December 2023. A total of 4481 CBs item were counted, and the density ranged from 0.37 to 1.76 m-2 with an average value of 0.99 m-2 across 12 sampling campaigns. The highest density was observed at service zones, and the fishing zones had the lowest density. The calculated CBPI values revealed that 75 % of the sampling stations were in the "severe pollution" while 25 % were classified as "high pollution" status, underscoring the prevalence of hazardous CBs across most areas of SMI. To tackle these issues requires regulatory measures, public awareness initiatives, and community involvement. Effective waste management and eco-friendly product promotion can help reduce CBs pollution risks in marine protected islands.

Microbial assisted multifaceted amelioration processes of heavy-metal remediation: a clean perspective toward sustainable and greener future

Rapidly increasing heavy metal waste has adversely affected the environment and the Earth's health. The lack of appropriate remediation technologies has worsened the issue globally, especially in developing countries. Heavy-metals contaminants have severely impacted the environment and led to devastating conditions owing to their abundance and reactivity. As they are nondegradable, the potential risk increases even at a low concentration. However, heavy-metal remediation has increased with the up-gradation of technologies and integration of new approaches. Also, of all the treatment methodologies, microbial-assisted multifaceted approach for ameliorating heavy metals is a promising strategy for propagating the idea of a green and sustainable environment with minimal waste aggregation. Microbial remediation combined with different biotechniques could aid in unraveling new methods for eradicating heavy metals. Thus, the present review focuses on various microbial remediation approaches and their affecting factors, enabling recapitulation of the interplay between heavy-metals ions and microorganisms. Additionally, heavy-metals remediation mechanisms adapted by microorganisms, the role of genetically modified (GM) microorganisms, life cycle assessment (LCA), techno-economic assessment (TEA) limitations, and prospects of microbial-assisted amelioration of heavy-metals have been elaborated in the current review with focus toward "sustainable and greener future."

Tracking the Variations in Trace and Heavy Elements in Smoking Products Marketed in Oman and Egypt: Risk Assessment After Implementation of Constraining Protocols

Tobacco smoking is becoming one of the major worldwide concerns regarding environmental pollution as well as health threats. In 2005, the World Health Organization (WHO) released the Framework Convention On Tobacco Control (FCTC), which outlined protocols for controlling tobacco products. Oman was one of the leading countries to follow these protocols; however, Egypt has only followed these protocols recently in 2020. One of the main challenges in tobacco product control is the variation in their trace element's types and amounts from country to country owing to differences in agriculture techniques and used chemical additives. Smoking releases different toxic metal ions found in them into the air, and hence, analyzing trace amounts of metals in tobacco smoking products is becoming more critical. The proposed research aims to evaluate the current levels of 11 heavy metals (namely, As, Pb, Cd, Co, Cr, Be, Ba, Mn, Ni, Fe, and Hg) in 22 tobacco products available in Egypt and Oman using inductively coupled plasma optical emission spectroscopy and a direct mercury analyzer. Although some elements such as Be, Co, and Cd were absent, the positive detection of As and Pb and the levels of Ba, Cr, and Ni are still alarming, especially for heavy smokers. The obtained results were then statistically related to previously published data in 2017 to explore the effectiveness of implementing the FCTC protocols within the Egyptian market. The outcomes suggested a positive impact of FCTC protocol implementation in Egypt, besides the lower levels of elemental content for Omani products compared to the Egyptian market.

The fate of leaked heavy metals in the urban environment under different persistence and precipitation scenarios

The use of tobacco will lead to the littering of a large number of filters, and the leakage of pollutants from them into the urban environment is a serious concern. The aim of this study was to analyze the leakage of heavy metals from filter and estimate the annual concentration of pollution leakage in different waste routes and different climatic conditions. The results showed that the highest and lowest density of filter in the studied urban environment were 0.51 and 0.01 number/m2, respectively. According to the estimated annual production of 306 million cigarette butts in the studied area, the leakage of the studied metals was estimated to be 401 g. The share of copper, chromium, and cadmium from the total leakage was 67%, 8.3%, and 1.88%, respectively. The leakage of studied metals in rainy conditions was 2.86 times more than sunny conditions. In different scenarios, the minimum and maximum annual leakage of metals were estimated 23,043 and 350,419 mg/year, respectively. Filters are a little but important source of heavy metal emission into the urban environment, the amount of pollution from which is affected by the consumers' behavior and the efficiency of the urban cleaning system. Education on the correct disposal of filters and increasing the efficiency of the urban cleaning system will lead to a reduction in pollution caused by tobacco consumption.

Reduction of the environmental and health consequences of cigarette butt recycling by removal of toxic and carcinogenic compounds from its leachate

Cigarette butt is a hazardous waste, and its management faces many challenges. The generation of leachate containing many pollutants including heavy metals is one of the limitations of recycling cigarette butts. The aim of this study was to reduce organic compounds and heavy metals in leachate resulting from cigarette butt recycling in an electrocoagulation reactor. For this purpose, two samples, including freshly smoked cigarette butts and littered cigarette butts, were processed and the treatment of leachate resulting from them was studied in an electrocoagulation reactor. The efficiency of leachate treatment was investigated in the treatment time of 10-40 min and current intensity of 20-100 mA. The results showed that the minimum reduction of chemical oxygen demand and turbidity was 25.3% and 33.4%, respectively. Increasing the current intensity and treatment time increased the efficiency of removing turbidity and chemical oxygen demand up to 47.1% and 41.2%, respectively, in optimum conditions. The reduction of nickel, chromium, cadmium, and lead in the lowest current density and minimum treatment time was more than 90%, which increased to more than 99% with the increase of the current density and treatment time. The use of electrocoagulation is a suitable solution to reduce heavy metals in leachate resulting from cigarette butt recycling, while the proper reduction of organic compounds in this type of leachate requires further treatment processes.

A comparative study of indexes used for litter pollution assessment in urban and public environments

Litter is a common pollution in the urban environment and public places such as beaches, which has serious health and economic consequences. Several indexes are used to interpret the pollution status caused by litter, which have different limitations and strengths. In this review, the efficiency and characteristics of different indexes were compared. For this purpose, related articles were searched in Scopus, PubMed, and Web of Knowledge, and after screening, 21 articles were selected. The main questions of this study included factors affecting the interpretation of pollution in different indexes and the criteria considered in each index. The results showed that the existing indexes based on the type of litter include two categories of comprehensive indexes such as Clean Environment Index and specific indexes such as Cigarette Butt Pollution Index. Also, the index can be divided into two categories in terms of spatial application, including general indexes such as Environmental Status and specific indexes such as Clean Coast Index. An important difference in the indexes is the importance of the impact of the pollution potential of different litter in the assessment of the status in indexes such as Clean Environment Index and Environmental Status, while indexes such as Clean Coast Index evaluate the status based only on the density of litter. According to the capabilities of each of the indexes, it is necessary to pay attention to the local needs as well as the characteristics of each index in using in urban management plans.

Influence of tobacco product wastes in a protected coastal reserve adjacent to urbanization

The present study, conducted at the Kendall-Frost Mission Bay Marsh Reserve in San Diego, California, aimed to assess tobacco-related pollutants in urban waters, a topic with limited prior research. Across 26 events occurring between November 2019 and February 2022, encompassing both wet and dry seasons at two outfall sites (Noyes St. and Olney St.), water and sediment samples were subjected to analysis for nicotine and cotinine levels, with Noyes St. displaying wide variation in nicotine concentrations, reaching a peak of 50.75 ng/L in water samples, whereas Olney St. recorded a peak of 1.46 ng/L. Wet seasons consistently had higher nicotine levels in water, suggesting the possibility of tobacco litter entering the reserve through stormwater runoff. Cotinine was detected in both sites in both water and sediment samples; however, these levels were considerably lower in comparison to nicotine concentrations. Limited research assesses aquatic environmental pollution from tobacco use and disposal, especially in protected areas like urban natural reserves. This study was conducted at the Kendall-Frost Mission Bay Marsh Reserve in San Diego, California, to evaluate tobacco-related pollutants in San Diego's urban waters. Twenty-six sampling events between November 2019 and February 2022, spanning wet and dry seasons at two outfall sites, were conducted. Nicotine and cotinine, a major ingredient of tobacco and its metabolite, were analyzed in the collected water and sediment samples. Nicotine concentrations differed substantially between the outfall locations (Noyes St. and Olney St.), with Noyes St. displaying wide variations, averaging at 9.31 (±13.24) ng/L with a maximum concentration of 50.75 ng/L, and Olney St. at 0.53 (±0.41) ng/L with a maximum concentration of 1.46 ng/L in water samples. In both locations, the nicotine concentrations in water samples were higher during wet seasons than dry seasons, and this pattern was more significant at Noyes St. outfall than at Olney St. outfall, which received not only stormwater runoff but also was connected to Mission Bay. Although this pattern did not directly align with sediment nicotine levels at both sites, maximum nicotine concentration in Noyes St. sediments during wet seasons was approximately 120 times higher than in Olney St. sediments. Regarding cotinine, Noyes St. outfall water averaged 3.17 ng/L (±1.88), and Olney St. water averaged 1.09 ng/L (±1.06). Similar to nicotine, the cotinine concentrations were higher in Noyes St. water and sediment compared to Olney St., but overall, the cotinine concentrations in both water and sediment were much lower than the corresponding nicotine concentrations. The study identifies urban stormwater runoff as a potential source of nicotine and cotinine pollution in a protected reserve, implicating tobacco product litter and human tobacco use as contributing factors.

Quality variations of leachate resulting from cigarette filter recycling as a challenge for its management

Recycling is known as a solution for cigarette filter management, but this may cause the release of trapped pollutants in it. Cigarette smoke toxins and chemicals that trapped in the cigarette filter can accumulate in the recycling leachate. In this study, littered cigarette filters and freshly smoked cigarette filters were recycled and the resulting leachate was analyzed. The results showed that the minimum and maximum Chemical Oxygen Demand (COD) of the studied leachates were 2100 mg/L and 11,300 mg/L, respectively. The maximum temporal variation in the studied leachate quality was 74.28%, but the maximum spatial variation was 314.2%. COD in the freshly smoked sample was 2600-9200 mg/L more than the littered samples. The average concentration of chromium, lead, nickel, and cadmium in littered samples was 0.023, 0.024, 0.045, and 0.019 mg/L, respectively. Environmental conditions such as humidity, the efficiency of the urban cleaning system in reducing the resistance of littered filters, the difference in the quality of the filter and tobacco, and the difference in smoking behaviors were effective in this variation. Reducing the toxicity of cigarette smoke and improving the efficiency of the urban cleaning system can lead to the same quality, but leachate treatment is necessary to reduce the environmental risk.

Toxicity of leachate from smoked cigarette butts to terrestrial animals: A case study on the earthworm Eisenia fetida

Cigarette butts, as easily overlooked littered wastes, have been evaluated for toxicity in various researches. In this study, we investigated the toxic effects of smoked cigarette butt leachate (SCBL) on the earthworm Eisenia fetida. The results showed the following: 1) E. fetida avoided SCBL in artificial soil, and the avoidance rate was positively correlated with the concentration of SCBL but negatively correlated with the exposure time; 2) the LD50 of SCBL on earthworms at 36 and 48 h of exposure were 3.71 × 10-4 and 2.67 × 10-4 butts/cm2, respectively. Moreover, both the body surface and intestinal tissues of E. fetida were damaged after exposure to SCBL; 3) the survival rates of E. fetida exposed to artificial soil with an SCBL of 3.6 butts/kg for 7 and 14 days were 80.00 ± 7.07 % and 68.00 ± 4.47 %, respectively; and 4) the mean biomass of the surviving E. fetida in all treated groups decreased with increasing SCBL concentration and exposure time. We concluded that SCBL exerted significant negative effects on soil animals, and suggested that SCBs should be collected, detoxified, and reused before entering the natural environment.

Citizen scientists study beach litter along 12,000 km of the East Pacific coast: A baseline for the International Plastic Treaty

Anthropogenic Marine Litter (AML) accumulating on beaches causes damage to coastal ecosystems and high costs to local communities. Volunteers sampled AML on 130 beaches along the central and southern East Pacific coasts, with AML densities ranging from 0.46 to 2.26 items m-2 in the different countries. AML composition was dominated by plastics and cigarette butts, the latter especially in Mexico and Chile. The accumulation of AML in the upper zones of the beaches and substantial proportions of cigarette butts, glass and metal pointed mainly to local sources. Statistical modelling of litter sources on continental beaches revealed that tourism, access and related infrastructure (e.g. parking lots) best explained AML densities, while plastic densities were also influenced by the distance from river mouths and national Gross Domestic Product. Large-scale monitoring can be a useful tool to evaluate the effectiveness of public policies that should primarily focus on land sources.

Evaluating cigarette butt pollution: Insights from Cox's Bazar Sea beach of Bangladesh

Cigarette butts (CBs) have serious harmful effects on the environment and living organisms despite their small size. This research aims to investigate the abundance, densities and pollution status of CBs in Cox's Bazar Sea beach. The survey was conducted between 11 a.m. and 5 p.m. in February 2023, during the peak season of the year. A total of 13,988 CBs were collected, and the mean density was 0.388 m-2 and ranges from 0.195 m-2 - to 0.689 m-2. The mean CBPI value was 7.78, which showed the "high pollution" status. According to CBPI analysis, 25 %, 41.67 %, 16.67 %, and 16.67 % were "severe pollution", "considerable pollution", "high pollution", and "pollution" status, respectively. From HII values, 91.67 % beach fell within the "Class III" category, indicating abundant toxic CBs in the study area. A total of 13 brands were identified, of which Derby (19.31 %), B&H (18.54 %), and Star (11.26 %) were more abundant brands. These findings from this study aim to increase awareness of the harmful effects of cigarette butts discarded intentionally or unintentionally by smokers.

Cigarette butt pollution in popular beaches of Morocco: Abundance, distribution, and mitigation measures

Cigarette butts pose a significant challenge in managing solid litter, with an estimated 4.5 trillion of them being discarded into the environment annually. This study investigated the pollution of eleven beaches along the Moroccan Mediterranean by cigarette butts compared to other types of marine litter between 2018 and 2023. Sampling was conducted using the visual survey technique according to a standardized protocol. A total of 50, 575 items were collected with cigarette butts (14.62 %) and plastic caps/lids drinks (10.93 %) being the most common. Our survey of eleven beaches revealed 7395 cigarette butts, giving an average density of 0.06/m2 comparable to other countries in the Mediterranean. The analysis of the results shows significant differences in the abundance cigarette butts according to the beach typology, seasonality, sediment type, and number of beach users. Moreover, the study discovered a decrease in beach pollution during the COVID-19 pandemic lockdown, resulting in less litter collected compared to pre- and post-pandemic periods. The Cigarette Butt Pollution Index was categorized as very low pollution in M'diq and Kaa Asrass, low pollution in Ksar Sghir, Fnideq, Amsa, Oued Laou, significant pollution in Martil and Nador and sever pollution in Saidia and Sababia. The CBPI was higher during summer and winter, significantly associated with the density levels of beach users. The study recommends immediate action by the local administration to prevent the potential pollution of groundwater and sand by toxic substances leached from cigarette butts.

Spatio-temporal distribution of cigarette butt contamination in urban beaches with varying levels of use

This study assessed the extent of cigarette butt contamination on two urban beaches in Recife-PE (Pernambuco State, Brazil) with varying levels of use. The study considered degradation levels and evaluated whether the brands varied by time, space, and beaches use. Ten transects (1.5 m wide) and spaced 10 m apart, were delimited on the beaches investigated. Twelve collections were made between May 2021 and January 2022, and the collected cigarette butts were evaluated based on degradation level, mass, size, and brand. In total, 10,275 cigarette butts were collected on both beaches, with P1 accounting for 96.91% of the found cigarette butts. The density of cigarette butts on the beaches was directly proportional to the level of use, with 8.85 butts/m2 in P1 and 1.05 butts/m2 in P2. Eighteen brands were identified, with brand (A) being the most popular regardless of the area. Significant differences (p ≤ 0.05) were found when evaluating the amount of butts/m2; Sundays with high precipitation presented reduced values of butts; more occupied areas presented transects with higher amounts; abundance in the summer; morphometry with higher values recorded in newly discarded butts; predominance of more degraded butts and brand diversity. Despite the difference in the number of butts/m2 between the areas, it was possible to identify that their abundance is very expressive, and that the monitored beaches present a high exposure to the contaminant.

Cigarettes butt littering: The story of the world's most littered item from the perspective of pollution, remedial actions, and policy measures

Cigarettes butt (CB) is one of the most littered items on the planet. This paper critically analyzes the factors responsible for CB littering, and associated environmental ramifications, and reviews all the possible technical, behavioural, and policy-based solutions. Even while smoking has declined globally, middle-income nations have seen an increase in consumption, which may be related to increased affordability and a lack of public awareness. The smokers' individual beliefs and habits, environmental ignorance, covert littering as a result of social taboos associated with smoking, and behavioural gaps between intention and action might all be contributing factors to CBs' littering behaviour. The low biodegradability of cellulose acetate filters and toxic chemical leaching from CBs are the most important aspects of CB environmental toxicity. The small size and low economic value of CB contribute to the inefficiencies of current waste collection and management systems. The current research on CB valorisation includes fired-clay bricks, asphalt concrete, biofilms, sound absorber, cellulose pulp, pesticides, and insecticides as downstream mitigation strategies. This study highlights the urgent need for policymakers to enforce regulations enabling innovative cigarette designs, the creation of deposit-refund schemes, extended producer responsibility and stringent waste collection mechanisms. Adopting gentler marketing strategies and non-confrontational behavioural nudges could result in an overall reduction in CB pollution.

Impact of Covid-19 pandemic lockdown on the urban litter and clean environment index

Changing the level of pollution in the urban environment is one of the consequences of Covid-19. Litter are one of the most important urban pollutants affected by the Covid-19 pandemic. In this research, the pollution level of urban areas during the Covid-19 pandemic was investigated by studying the urban environment. To this end, the protocol of observation and counting was used and litter were studied in two groups including common litter and Covid-19 related litter in Yasuj, Iran. The results were interpreted based on the clean environment index (CEI). The time of observation was selected based on the peak of the disease and the decline in the incidence rate. The results showed that on average, at the peak of the disease, the density of the litter was reduced by 19% compared to the low lockdown related to Covid-19. The CEI on average was 4.76 at the peak of the disease that was interpreted in the clean status, while the CEI on average was 5.94 at the low lockdown related to Covid-19 so interpreted in the moderate status. Among urban land uses, recreational areas with a difference of more than 60% showed the greatest impact caused by Covid-19, while in commercial areas this difference was less than 3%. The effect of Covid-19 related litter on the calculated index was 73% in the worst case and 0.8% in the lowest case. Although Covid-19 decreased the number of litter in urban areas, the emergence of Covid-19 lockdown related litter was a cause for concern and led to increasing the CEI.

A combined method for human health risk area identification of heavy metals in urban environments

Multi-medium heavy metals pollution is a crucial pathway to destroy the urban environmental resources cycle. In this study, Nanjing of China, a typical mega city, was taken as the study area. Compared with other cities or countries, Cr, Cu and Zn in human nails and hair in the study area have higher concentration characteristics, while Cd and Pb have lower concentration characteristics. By combining the health risk status of heavy metals in soil and dustfall, the spatial clustering characteristics of heavy metals in soil dustfall and the concentration information of heavy metals in humans in the study area, a potential toxic risk area identification method based on soil-dustfall-human (SDB-HR) was established. Through Monte Carlo analysis, it's found that the risk of Zn and Cr in soil-dustfall to human health is relatively high, with the probability of carcinogenesis reaching 51.2 % and 50.2 %, respectively. By the proposed method, different levels of heavy metal risk areas in urban environments can be more reasonably and effectively identified, which will provide important technical and theoretical support for the precise management of heavy metals in urban environments.

Giving New Life to Waste Cigarette Butts: Transformation into Platinum Group Metal-Free Electrocatalysts for Oxygen Reduction Reaction in Acid, Neutral and Alkaline Environment

Following the core theme of a circular economy, a novel strategy to upcycle cigarette butt waste into platinum group metal (PGM)-free metal nitrogen carbon (M-N-C) electrocatalysts for oxygen reduction reaction (ORR) is presented. The experimental route was composed of (i) the transformation of the powdered cigarette butts into carbonaceous char via pyrolysis at 450 °C, 600 °C, 750 °C and 900 °C, (ii) the porosity activation with KOH and (iii) the functionalization of the activated chars with iron (II) phthalocyanine (FePc). The electrochemical outcomes obtained by the rotating disk electrode (RRDE) technique revealed that the sample pyrolyzed at 450 °C (i.e., cig_450) outperformed the other counterparts with its highest onset (Eon) and half-wave potentials (E1/2) and demonstrated nearly tetra-electronic ORR in acidic, neutral and alkaline electrolytes, all resulting from the optimal surface chemistry and textural properties.

Spatial and temporal variation of CBPI and leakage of heavy metals from cigarette butts into the urban environment

More than 5 trillion cigarettes are produced in the world every year. This hazardous waste is one of the most important litter in the environment. The purpose of this study was to investigate the density and dispersion of cigarette butts in the urban environment and to estimate the leakage of pollution from it to the environment. For this purpose, the cigarette butt pollution index was used in 14 locations. Observations were made during a year and once a month for each location. The study of the locations was done with the same conditions on weekend and working days. The amount of heavy metal leakage was estimated based on the average weight of cigarette butts and the ratio of metal leakage in different weather conditions. The results showed that the annual average of index for the studied locations was 1.36 (SD 0.11) to 10.6 (SD 1.23). Based on this, 28.5% of the locations were in the low pollution status and 42.8% were in the significant pollution status and worse. On average, the index on weekend decreased by 32.3 percent in all locations, and the average index of the studied locations in spring and summer was 26.2 percent higher than in autumn and winter. The average leakage of heavy metals including chromium, cadmium, zinc, lead, copper, and nickel from littered cigarette butts in commercial, residential, and recreational areas was estimated to be 0.27, 0.079, and 0.17 µg per square meter, respectively. Cigarette butt is one of the most abundant litter in the studied area, which is the source of many pollutants, including heavy metals. This hazardous waste is a serious threat to the urban environment.

Toward a sustainable circular economy for cigarette butts, the most common waste worldwide on the coast

The circular economy is based on the maximum use of resources by reducing, reusing, and recycling the elements used. Currently, the items littered most frequently in the world are cigarettes butts (CB) as these debris are freely disseminated in the marine habitat, they are generally difficult to collect and very complex to recycle. Litter CB is a great social problem that generates excessive economic costs and serious environmental problems. CB is also not biodegradable and highly toxic to marine organisms and presents a distinctive mixture of physical and chemical contamination. However, little research has been done on the management and recycling of this dangerous waste. Several proposals have been made to incorporate this waste into high-volume articles of direct production or recycling, but collection logistics are lacking since the current system is inefficient, in addition to the poor environmental behaviour of citizens. This work presents a current synthesis of the CB problem from all its possible aspects in order to have a global vision of the life cycle of the CB, indicating both the known and the gaps in the knowledge of each of them, and intends to give a general outline of the steps to follow to try to end such a worrying problem at the global level.

Cigarette butts in two urban areas from Brazil: Links among environmental impacts, demography and market

Environmental impacts are currently linked to smoking cigarette behavior, as cigarette butts (CBs) represent the most common litter item in natural areas. Despite this, even the best ranked Brazilian cities, in terms of urban cleaning, have no information about urban littered CBs. Thus, CBs were monitored in Santos and Niterói cities, aiming to assess contamination, Cigarette Butt Pollution Index (CBPI) and the illegal market size. CBs were collected in 36 walkways considering different land usage types and urban density levels. The CBPI was calculated, and brands were used to identify the size of the illegal market. CBs contamination in Santos (0.25 CBs/m²) was three times higher than Niterói (0.08 CBs/m²) and their occurrence and distribution presented no relationship with land usage types and urban population densities levels. CBPI = 17.6 was severe and the highest so far reported. A total of 28 cigarette brands were found both studied cities. Further, illegal cigarette consumption in Santos and Niteroi was estimated, based on brands of collected CBs, at 25.2% and 36.8%, respectively. Such data may be valuable for implementation of logistic reverse actions seeking to environmentally sustainable and socially resilient cities. Cigarette consumption threatens human life and the environment, and tobacco companies should be accountable for the pollution they generate.

Cigarette butts as a super challenge in solid waste management: a review of current knowledge

Filtered cigarette is the most common type of tobacco used and cigarette butt is the most important environmental consequence of smoking. This study aimed to investigate the cigarette butt management and identify future needs to improve the current situation. The results showed that cigarette butts are the most abundant and widespread hazardous waste in the world. The current form of cigarette butt management has inferior performance that faced waste management systems with serious challenges. The results showed that reducing the littering rate and recycling are known as basic strategies in the management of this hazardous waste. Future studies should focus on reducing cigarette butt pollution and the amount of pollutant leakage from them.

Cigarette butt littering consequences: a study of pollution rate on beaches and urban environments

Cigarette butts are hazardous wastes that are not properly discarded by most smokers. They are one of the most abundant litters in the environment and a threat to various organisms because they leak numerous pollutants. This study aimed to assess the distribution of cigarette butts in a coastal city south of the Caspian Sea in Mazandaran Province, Iran. Observations were performed using the visual survey technique based on standardized protocol. The results showed 11,261 littered cigarette butts in 15 studied urban areas ( an average of 0.306 units per square meter). Also, the average density of littered cigarette butts on the studied beaches was 0.106 per square meter. The littered cigarette butts had significant spatial variation, and the number of counts was 135 to 2090. The land-use has a significant effect on the density of littered cigarette butts due to its population density. The inquiry's index demonstrated that 33.3% of the studied urban areas are high pollution and severe pollution, while all beaches are high and severe. Therefore, a significant focus must be considered to reduce cigarette butts littering due to the collection problems and challenges of cigarette butt management. Because the pollution on the beaches is higher than in urban areas, improving waste management services and establishing a regular cleaning program are essential.

Modeling the Biosorption Process of Heavy Metal Ions on Soybean-Based Low-Cost Biosorbents Using Artificial Neural Networks

Pollution of the environment with heavy metals requires finding solutions to eliminate them from aqueous flows. The current trends aim at exploiting the advantages of the adsorption operation, by using some low-cost sorbents from agricultural waste biomass, and with good retention capacity of some heavy metal ions. In this context, it is important to provide tools that allow the modeling and optimization of the process, in order to transpose the process to a higher operating scale of the biosorption process. This paper capitalizes on the results of previous research on the biosorption of heavy metal ions, namely Pb(II), Cd(II), and Zn(II) on soybean biomass and soybean waste biomass resulting from biofuels extraction process. The data were processed by applying a methodology based on artificial neural networks (ANNs) and evolutionary algorithms (EAs) capable of evolving ANN parameters. EAs are represented in this paper by the differential evolution (DE) algorithm, and a simultaneous training and determination of the topology is performed. The resulting hybrid algorithm, hSADE-NN was applied to obtain optimal models for the biosorption process. The expected response of the system addresses biosorption capacity of the biosorbent (q, mg/g), the biosorption efficiency (E, %), as functions of input parameters: pH, biosorbent dose (DS, mg/g), the initial concentration of metal in the solution (c0, mg/L), contact time (tc, h), and temperature (T, °C). Models were developed for the two output variables, for each metal ion, finding a high degree of accuracy. Furthermore, the combinations of input parameters were found which can lead to an optimal output in terms of biosorption capacity and biosorption efficiency.