Discarded cigarette butts attract females and kill the progeny of Aedes albopictus

Risk assessment of cigarette butts and microplastic pollution in a drinking and irrigation water basin of West Anatolia, Türkiye

Cigarette butts (CBs) and Microplastics (MPs) have serious harmful effects on the environment and living organisms despite their small size. This research aims to investigate the abundance and pollution status of CBs and MPs in Tahtalı Dam Basin (West Anatolia, Türkiye) which is the most important drinking and irrigation water resources. Clean Environment Index (CEI) and Cigarette Butt Pollution Index (CBPI) were used to determine pollution degree of the basin. The total number of CBs were 1.478 items, the total number of MPs were 477 items/m2 in the basin. As a result of this study, MP particles weren't found in Balaban Stream. Highest number of MP particles observed in 100-250 μm (45%) size class. The most abundant MP type and colour were, fragment (54%) and white (42%), respectively. Polyethylene terephthalate (50%) was the most abundant type of polymer according to the ATR- FTIR analysis. As a result of the CEI and CBPI, the upstream stations of the stream were classified as "clean" status, while downstream sampling points of the stream and Balaban Lake coasts were classified as "extremely dirty" status. The calculated volumes of MP particulates from mining facility, agricultural and recreational activities indicate that anthropogenic factors are the most important MP source in the Tahtalı Dam Basin. This study is the first study about MP and CB pollution of the freshwater ecosystems in the region.

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.

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.

A comprehensive review on triple R eco-management strategies to reduce, reuse and recycle of hazardous cigarette butts

Cigarettes are the globally consumed product that contributes to public health problems and is the source of the most prevalent form of litter in the world, Cigarette butts. Cigarette butts are a major source 4000 toxic chemicals, affecting the health of wildlife, humans, and the environment and their decomposition can take years due to the resistance of cellulose acetate to bacterial and fungal degradation. In 2016, the world production of cigarettes exceeded 5.7 trillion, with the majority of them consisting of cellulose acetate filters. Consequently, a massive amount of hazardous waste leaches out in the environment. Incineration and landfilling are methods of disposal, but they can result in the emission of harmful fumes and be costly. To combat this environmental issue, researchers have explored the recycling of cigarette butts in various materials, including asphalt concrete, fired clay bricks, and as a carbon source, among others. Various approaches can be used to reduce cigarette butts pollution, but efficient collection logistics by consumers remains a crucial factor for successful recycling. This paper provides innovative solutions to mitigate the cigarette butts litter problem and the feasibility of recycling methods. Despite recent progress in cigarette butts recycling solutions, there is still much room for research in this area.

Cigarette: an unsung anthropogenic evil in the environment

The world's population is growing steadily, and this trend is mirrored by a sharp rise in the number of people who smoke cigarettes. Instead of properly disposing of their cigarette waste, most people simply toss them aside, leading to serious environmental consequences. According to previous statistics, in 2012 alone, 6.25 trillion cigarettes were consumed by 967 million chain smokers. Past studies have shown that up to 30% of global litter is made up of cigarette waste. These discarded cigarette butts are non-biodegradable and contain over 7000 toxicants such as benzene, 1,3-butadiene, nitrosamine ketone, N-Nitrosonornicotine, nicotine, formaldehyde, acrolein, ammonia, aniline, polycyclic aromatic hydrocarbons, and various heavy metals. These toxicants have a negative impact on the habitats of wildlife and can cause serious health problems such as cancer, respiratory disorders, cardiac issues, and sexual dysfunction. Although it is still unclear how littered cigarettes affect plant growth, germination, and development, it is clear that they have the potential to harm plant health. Just like single-use plastic, trashed cigarette butts are a critical new rising form of pollution that requires scientific attention for effective recycling and disposal management. It is important to properly dispose of cigarette waste to protect the environment and wildlife, as well as to prevent harm to human health.

Small Butt Harmful: Individual- and Population-Level Impacts of Cigarette Filter Particles on the Deposit-Feeding Polychaete Capitella teleta

In the marine environment, discarded cigarette filters (CFs) deteriorate and leach filter-associated chemicals. The study aim was to assess the effects of smoked CFs (SCFs) and non-smoked CFs (NCFs) particles on individual life-history traits in the deposit-feeding polychaete Capitella teleta and extrapolate these to possible population-level effects. C. teleta was exposed to sediment-spiked particles of NCFs and SCFs at an environmentally realistic concentration (0.1 mg particles g^-1 dw sed) and a 100-fold higher (10 mg particles g^-1 dw sed) concentration. Experimental setup incorporated 11 individual endpoints and lasted approximately 6 months. There were significant effects on all endpoints, except from adult body volume and egestion rate, in worms exposed to 10 mg SCF particles g^-1 dw sed. Although not statistically significant, there was ≥50% impact on time between reproductive events and number of eggs per female at 0.1 mg SCF particles g^-1 dw sed. None of the endpoints was significantly affected by NCFs. Results suggest that SCFs are likely to affect individual life-history traits of C. teleta, whereas the population model suggests that these effects might not transform into population-level effects. The results further indicate that chemicals associated with CFs are the main driver causing the effects rather than the CF particles.

Chemical contents and toxicity of cigarette butts leachates in aquatic environment: A case study from the Persian Gulf region

Cigarette butts (CBs) are one of the most commonly found types of litter contaminating the aquatic environment. However, the environmental risks posed by CBs need further investigation. In this study, the in-vivo toxic effects of various concentrations of CB leachates on juvenile (5.45 ± 1.36 gr and 7.08 ± 1.12 cm) fish (Periophthalmus waltoni) were evaluated. The LC50 values of CB leachate from smoked cigarette butts with tobacco (SCB) were 3.75, 3.0, 1.94, and 1.37 CBs/L in 24, 48, 72, and 96 h exposure times, respectively. The LC50 values for leachate of smoked CBs without tobacco (SF) were 7.58, 6.22, 4.73, and 2.9 CBs/L at 24, 48, 72, and 96 h exposure times, respectively. In the case of leachate from unsmoked filters (USF), LC50 values were 14.68, 12.44, 10.19, and 7.46 CBs/L in 24, 48, 72, and 96 h exposure time, respectively. The mean concentrations of heavy metals and polycyclic aromatic hydrocarbons in SCBs leachates were higher than in SF and USF leachates. Our findings report that even low concentrations of CBs leachates can led to lethality of P. waltoni and may pose a threat to their population density.

Preparation of a cellulose acetate membrane using cigarette butt recycling and investigation of its efficiency in removing heavy metals from aqueous solution

This study investigated the recycling of freshly-smoked cigarette butts (FCBs) and unsmoked cigarette filters (UCFs) into a cellulose acetate (CA) membrane. The both samples were prepared by means of a combination of seven cigarette brands, and the phase inversion method was used to recycle each sample into a membrane using N-methyl-2-pyrrolidone. The efficiency of the prepared membranes for the removal of chromium, cadmium, and lead from an aqueous solution in a forward osmosis reactor was investigated. The results showed that the both membranes had a smooth surface and macrovoids. The flux of the prepared membranes from the UCFs and FCBs recycling were 14.8 and 13.2 LMH, respectively. The porosity and reverse salt of the UCFs membrane were 61% and 3.5 gMH, while those for FCBs membrane were 58% and 3.9 gMH. The observed metal removal efficiency of the both membranes was in the range of 85 to 90%. However, increasing the concentration of metals up to five times caused a slight decrease in the removal efficiency (less than 5%).

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.

The ecological impacts of discarded cigarette butts

Cigarette butts, one of the most littered items globally, present a unique challenge to ecosystems due to their ubiquity, persistence, and potential for harm. Over 35 studies have examined the toxicity of cigarette butts in biota from aquatic and terrestrial habitats from microbes to mice, but many organisms and habitats have not been tested. Two-thirds of studies are on aquatic organisms, and lethal effects were common. Research on the impacts on terrestrial life is lagging behind. Cigarette butts can affect the growth, behaviour, and reproductive output of individual organisms in all three habitats, but research on wider effects on biodiversity and ecosystem functioning is lacking. Here, we summarise the ecotoxicological concerns and identify important knowledge gaps for future research.

Environmental fate of cigarette butts and their toxicity in aquatic organisms: A comprehensive systematic review

Cigarette butts (CBs) are the most frequently littered pieces of environmental wastes which are released both directly and indirectly into the environment and finally may reach aquatic environments and contaminate aquatic biomes. However, to date, there is no comprehensive review on the extent and magnitude of the potential effects of CBs on aquatic organisms. Hence, a systematic review of published studies was conducted in this paper to survey the fate of CBs in the aquatic environments and also the impacts of exposure to CBs on survival, growth, and reproduction of aquatic organisms. The gathered data showed that the leachates of CBs in the aquatic environment could extremely be toxic for various organisms and increasing the exposure time, increases the mortality rate. In addition, smoked filtered CBs with tobacco remnants have higher mortality rate compared to unsmoked filtered butts (USFs) for Hymenochirus curtipes, Clarias gariepinus, tidepool snails, Atherinops affinis and Pimephales promelas. The fate of CBs in the aquatic environments is affected by various factors, and prior to sinking they are floated for a long time (long distance). Hence, CBs and their associated toxic chemicals might be ingested by diverse aquatic organisms. However, further studies are necessary to understand the exact toxicity of CBs on different freshwater and marine organisms and also their fate in the aquatic media. The results of this review showed the essentiality of regulations to prevent the release of chemical and toxic compounds into the aquatic environments.

Toxicity of cigarette butts and possible recycling solutions-a literature review

Tobacco is a worldwide-consumed product, which in addition to causing public health-related issues is responsible for the most common form of litter in the world-smoked cigarette butts (CBs). A large attention has been drawn to this question, since this specific waste type tends to end up in terrestrial and aquatic ecosystems, posing serious threat to a range of life forms. Decomposition may take several years to occur because cellulose acetate is hardly accessible, before deacetylation, by bacteria and fungi. This review concerns the toxicity derived from smoked cigarette butts, as well as innovative ecological solutions for solving the CB litter problem. Toxicity studies have demonstrated the critical influence of chemicals present in smoked CBs to the environment as a whole, but also the physical contaminating potential considering micro- and nanoparticles derived from CB material. Nevertheless, several technological approaches were aimed at unveiling hidden value within used CBs, as well as propositions for incorporation of this residue in large volume production items or direct recycling. In summary, several methods are available to alleviate CB pollution, while appropriate and efficient collection logistics by consumers appears as the main bottleneck for an effective recycling. It is also clear that while considerable progress has been made recently in light of CB recycling solutions, there is still a vast research capacity in this regard.

Genotoxicity and phytotoxicity comparison of cigarette butt with cigarette ash

The damage potential of cigarette butt and cigarette ash was determined and compared using genotoxicity and phytotoxicity assessments. The concentrations of five heavy metals, As, Cr, Cd, Pb, and Ni, were determined in both cigarette butt and ash leachates to find out if the results of heavy metals are in parallel with toxicity findings. Cigarette ashes and cigarette butts were soaked in distilled water for 7 days. Six leachate butt concentrations, including 200, 100, 50, 25, 12.5, and 6.25 piece/L, were examined. HUVEC cells (human umbilical vein endothelial cells) were exposed to these dilution series for genotoxicity, and Vicia faba seeds were exposed to the same dilution series for phytotoxicity assessments. Three parameters of genotoxicity, including tail length, %DNA in tail, and tail moment, were obtained by the comet assay method, and three parameters of phytotoxicity, including germination rate, root length, and water content percentage, were employed. The results showed that cigarette ash at the concentrations of 50, 25, 12.5, and 6.25 pc/L brings about DNA damage. Meanwhile, cigarette butt causes DNA damage at the concentrations of 100, 50, 25, and 12.5 pc/L. The highest concentrations (200 pc/L for cigarette butt and 200 and 100 pc/L for cigarette ash) were considered lethal for HUVEC cells. Besides, the levels of genotoxicity in the cigarette ash were twice as high as those in the cigarette butt. The Vicia faba phytotoxicity test demonstrated a germination rate restriction from 100 to 52 and 100 to 0% for cigarette butt and cigarette ash, respectively. It also caused a reduction in the length of roots from 35 to 7.85 and 3 mm for cigarette butt and cigarette ash, respectively. The moisture amounts of cigarette remnants had a decline from 93.14 to 44.61 and 36.72% for cigarette butt and cigarette ash, respectively. Concentrations of As, Cr, Cd, Pb, and Ni were 17.45, 2.5, 0.15, 6, and 0.62 ppb in the butt leachate and 7.21, 2.64, 0.29, 13.61, and 1.24 ppb in the ash leachate, respectively, indicating that heavy metals could explain the higher toxicity of cigarette ash. Based on the present study, cigarette ash imposes not only higher levels of genotoxicity and phytotoxicity but also more values of toxic heavy metals on our planet. Thus, cigarette ash plays a major role in environmental pollution, and the importance of cigarette ashes should receive attention even more than cigarette butts. This paper casts new light on the toxic impacts of cigarette ash.

The fate of cigarette butts in different environments: Decay rate, chemical changes and ecotoxicity revealed by a 5-years decomposition experiment

Cigarette butts (CBs) are the most common litter item on Earth but no long-term studies evaluate their fate and ecological effects. Here, the role of nitrogen (N) availability and microbiome composition on CBs decomposition were investigated by a 5-years experiment carried out without soil, in park grassland and sand dune. During decomposition, CBs chemical changes was assessed by both ¹³C CPMAS NMR and LC-MS, physical structure by scanning electron microscope and ecotoxicity by Aliivibrio fischeri and Raphidocelis subcapitata. Microbiota was investigated by high-throughput sequencing of bacterial and eukaryotic rRNA gene markers. CBs followed a three-step decomposition process: at the early stage (∼30 days) CBs lost ∼15.2% of their mass. During the subsequent two years CBs decomposed very slowly, taking thereafter different trajectories depending on N availability and microbiome composition. Without soil CBs showed minor chemical and morphological changes. Over grassland soil a consistent N transfer occurs that, after de-acetylation, promote CBs transformation into an amorphous material rich in aliphatic compounds. In sand dune we found a rich fungal microbiota able to decompose CBs, even before the occurrence of de-acetylation. CBs ecotoxicity was highest immediately after smoking. However, for R. subcapitata toxicity remained high after two and five years of decomposition.

The toxicity and valorization options of cigarette butts

Cigarette butts, one of the most abundant forms of waste in the world, contain more than 4000 toxic chemicals and pose serious risks to the health of wildlife, humans, and marine and freshwater organisms. Although trivial in size, trillions of cigarettes are produced every year worldwide, resulting in the accumulation of tonnes of toxic waste litter. In 2016, a world production of over 5.7 trillion cigarettes was reported with the majority comprising cellulose acetate filters - a polymer with poor biodegradability. Depending on the environmental conditions, cellulose acetate filters can take up to 10 years to decompose during which time they leach heavy metals and toxic chemicals into the environment. Although possible disposal methods for collected cigarette butt waste include incineration and landfilling, both techniques may result in the release of hazardous fumes and can be costly. However, recycling CBs in different materials could be a possible solution for this concurrent environmental pollution. A number of novel studies have been publicized on recycling cigarette butts with encouraging results, and several methods have been studied, including recycling of cigarette butts in asphalt concrete and fired clay bricks, as a carbon source, sound absorbing material, corrosion inhibitor, biofilm carrier, and many more. Hence, this paper provides a comprehensive review and discussion of various studies that have been carried out on the toxicity and valorization of cigarette butt waste and investigates the feasibility and sustainability of recycling methods adopted. Further research and developments are essential for the widespread application of recycling cigarette butts.

Littered cigarette butt as a well-known hazardous waste: A comprehensive systematic review

Most of cigarettes used in the world have filters. Following smoking, the cigarette butts (CBs) are often littered as wastes in the environment. CBs generally contain several toxic substances that are trapped in the cigarette filter. Filters are made of non-biodegradable materials and remain in the environment for a long time. Within this study, it is attempted to systematically review the articles on CBs and find out the answers to the problems associated with the factors including quantity, distribution, origin and toxicity of CBs in the environment. It is estimated that approximately 5.5 trillion cigarettes are being produced annually in the world and the CB wastes would reach 1.2 million tons and increase by 50% until 2025. CBs contain thousands of dangerous chemicals such as arsenic, benzene, hydrogen cyanide, PAHs, pyridine, heavy metals and so forth. It is also believed that eachCB can pollute 1000 liters of water. Given the inadequacy of mechanical equipment as well as the cost of collecting these wastes, there should be a special focus on these items as follows: producing cigarettes with degradable filters, reducing the rate of smoking in the world, reducing the toxic and chemical substances in the process of plant growth, processing and production of cigarettes, training people to discard CBs properly, putting legal and financial pressures on cigarettes production, and the last but not least, providing effective solutions for collecting CBs.

A systematic review on cigarette butt management as a hazardous waste and prevalent litter: control and recycling

Annually, over 5.5 trillion cigarettes are produced worldwide, and it is estimated that 4.5 trillion cigarette butts (CBs) are still being littered in the world. The dispersal of the CBs has caused this hazardous waste to be considered as one of the most important litters and environmental risks all over the world. This systematic study with the search protocol definition and keyword identification was developed to find the CBs control and recycling methods by searching in five scientific databases. Founded articles were monitored and finally, 35 related articles were selected and studied by the authors. The results of this study showed that CBs recycling methods have been tested in 10 specific categories all over the world. The CBs have been applied without any pre-processing methods in the bricks and asphalt production. However, other applications of the CBs such as the absorbent material production, vector control, and use as a biofilm carrier in wastewater treatment need various processing methods. The researchers also presented models and suggestions such as taxes, penalties, and public education for the control of CBs littering. Despite the innovative methods applied for the CBs recycling in previous studies, CBs have not received much attention in terms of pollutant control and environmental issues in recycling processes.

Cigarette butts may have low toxicity to soil-dwelling invertebrates: Evidence from a land snail

Cigarette butts are a common form of litter that is often deposited on soil, where toxins from butts may affect soil-dwelling organisms. We examined possible toxicity of cigarette butts to the woodland snail Anguispira alternata using a toxicity study with cigarette butt effluent and a lab-based habitat choice experiment in which snails could feed or rest on areas with different butt densities. No mortality occurred during the 32-day toxicity study, which used six effluent concentrations ranging from 0 to 4butts/l (0 to 0.92butts/kg of soil). Neither food consumption nor snail growth differed among the effluent concentrations. When provided a choice among four habitats with 0 to 4 cigarette butts, snails selected to preferentially rest in the 0-butt habitat and avoided the 4-butt habitat. This distribution pattern was strong during the first wk. but became weaker over time and largely disappeared by the end of the 3-wk experiment. Snails did not discriminate among butt densities when feeding. This is the first toxicity test using cigarette butts on soil-dwelling invertebrates. Declining aversion to cigarette butts over a 3-wk period may indicate declining toxicity of terrestrially deposited butts as they age, but further testing is needed.

Managing wastes as green resources: cigarette butt-synthesized pesticides are highly toxic to malaria vectors with little impact on predatory copepods

The development of novel mosquito control tools is a key prerequisite to build effective and reliable Integrated Vector Management strategies. Here, we proposed a novel method using cigarette butts for the synthesis of Ag nanostructures toxic to young instars of the malaria vector Anopheles stephensi, chloroquine (CQ)-resistant malaria parasites Plasmodium falciparum and microbial pathogens. The non-target impact of these nanomaterials in the aquatic environment was evaluated testing them at sub-lethal doses on the predatory copepod Mesocyclops aspericornis. Cigarette butt-synthesized Ag nanostructures were characterized by UV-vis and FTIR spectroscopy, as well as by EDX, SEM and XRD analyses. Low doses of cigarette butt extracts (with and without tobacco) showed larvicidal and pupicidal toxicity on An. stephensi. The LC₅₀ of cigarette butt-synthesized Ag nanostructures ranged from 4.505 ppm (I instar larvae) to 8.070 ppm (pupae) using smoked cigarette butts with tobacco, and from 3.571 (I instar larvae) to 6.143 ppm (pupae) using unsmoked cigarette butts without tobacco. Smoke toxicity experiments conducted against adults showed that unsmoked cigarette butts-based coils led to mortality comparable to permethrin-based positive control (84.2 and 91.2%, respectively). A single treatment with cigarette butts extracts and Ag nanostructures significantly reduced egg hatchability of An. stephensi. Furthermore, the antiplasmodial activity of cigarette butt extracts (with and without tobacco) and synthesized Ag nanostructures was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of P. falciparum. The lowest IC₅₀ values were achieved by cigarette butt extracts without tobacco, they were 54.63 μg/ml (CQ-s) and 63.26 μg/ml (CQ-r); while Ag nanostructure IC₅₀ values were 72.13 μg/ml (CQ-s) and 77.33 μg/ml (CQ-r). In MIC assays, low doses of the Ag nanostructures inhibited the growth of Bacillus subtilis, Klebsiella pneumoniae and Salmonella typhi. Finally, the predation efficiency of copepod M. aspericornis towards larvae of An. stephensi did not decrease in a nanoparticle-contaminated environment, if compared to control predation assays. Overall, the present research would suggest that an abundant hazardous waste, such as cigarette butts, can be turned to an important resource for nanosynthesis of highly effective antiplasmodials and insecticides.

Coffee, its roasted form, and their residues cause birth failure and shorten lifespan in dengue vectors

In dengue mosquitoes, successful embryonic development and long lifespan are key determinants for the persistence of both virus and vector. Therefore, targeting the egg stage and vector lifespan would be expected to have greater impacts than larvicides or adulticides, both strategies that have lost effectiveness due to the development of resistance. Therefore, there is now a pressing need to find novel chemical means of vector control. Coffee contains many chemicals, and its waste, which has become a growing environmental concern, is as rich in toxicants as the green coffee beans; these chemicals do not have a history of resistance in insects, but some are lost in the roasting process. We examined whether exposure to coffee during embryonic development could alter larval eclosion and lifespan of dengue vectors. A series of bioassays with different coffee forms and their residues indicated that larval eclosion responses of Aedes albopictus and Ae. aegypti were appreciably lower when embryonic maturation occurred in environments containing coffee, especially roasted coffee crude extract (RCC). In addition, the lifespan of adults derived from eggs that hatched successfully in a coffee milieu was reduced, but this effect was less pronounced with roasted and green coffee extracts (RCU and GCU, respectively). Taken together, these findings suggested that coffee and its residues have embryocidal activities with impacts that are carried over onto the adult lifespan of dengue vectors. These effects may significantly reduce the vectorial capacity of these insects. Reutilizing coffee waste in vector control may also represent a realistic solution to the issues associated with its pollution.

Colour Cues: Effects of Ipomoea Plant Extract on Culex quinquefasciatus Say Gravid Females in Choosing Oviposition Site

The interaction between plants and insects is dynamic, and may favour either the plant or the insect. Plant chemicals are deeply implicated in this relationship and influence insect behaviour. Here, we investigated the oviposition behaviour response of Culex quinquefasciatus mosquitoes based on the colour cues produced by Ipomoea cairica leaves extract. In this study, two sets of oviposition choice experiments were conducted: (1) single solution in a cage; and (2) multiple concentration solutions in a cage. In the single solution experiment, only 1 available oviposition site was offered to 5 gravid females and in the multiple concentration tests, 4 available oviposition sites were offered to 20 gravid females. The tested concentrations were set up at 100 mL of: (1) control (distilled water only); (2) 50 ppm; (3) 150 ppm; and (4) 300 ppm of I. cairica plant extracts. The highest concentration of 300 ppm appeared to show the highest intensity with the darkest colour followed by 150 ppm and 50 ppm concentrations. More gravid females were found drowned in the highest concentration, 300 ppm of acethonilic leaves extract, compared to 150 ppm and 50 ppm of the tested extract. No eggs were found in all tested solutions. The studied extract was found to effectively attract gravid Cx. quinquefasciatus females and subsequently cause mortality and inhibit egg deposition. The interference caused by the acethonilic extract of I. cairica on the oviposition activity of Cx. quinquefasciatus can result in better control of the vector insect.

Exposure of a Dengue Vector to Tea and Its Waste: Survival, Developmental Consequences, and Significance for Pest Management

Dengue mosquitoes are evolving into a broader global public health menace, with relentless outbreaks and the rise in number of Zika virus disease cases as reminders of the continued hazard associated with Aedes vectors. The use of chemical insecticides-the principal strategy against mosquito vectors-has been greatly impeded due to the development of insecticide resistance and the shrinking spectrum of effective agents. Therefore, there is a pressing need for new chemistries for vector control. Tea contains hundreds of chemicals, and its waste, which has become a growing global environmental problem, is almost as rich in toxicants as green leaves. This paper presents the toxic and sublethal effects of different crude extracts of tea on Aedes albopictus. The survival rates of larvae exposed to tea extracts, especially fresh tea extract (FTE), were markedly lower than those in the control treatment group. In addition to this immediate toxicity against different developmental stages, the extracts tested caused a broad range of sublethal effects. The developmental time was clearly longer in containers with tea, especially in those with young larvae (YL) and FTE. Among the survivors, pupation success was reduced in containers with tea, which also produced low adult emergence rates with increasing tea concentration. The production of eggs tended to be reduced in females derived from the tea treatment groups. These indirect effects of tea extracts on Ae. albopictus exhibited different patterns according to the exposed larval stage. Taken together, these findings indicate that tea and its waste affect most key components of Ae. albopictus vectorial capacity and may be useful for dengue control. Reusing tea waste in vector control could also be a practical solution to the problems associated with its pollution.

Coffee and its waste repel gravid Aedes albopictus females and inhibit the development of their embryos

BACKGROUND

Dengue is a prevalent arboviral disease and the development of insecticide resistance among its vectors impedes endeavors to control it. Coffee is drunk by millions of people daily worldwide, which is associated with the discarding of large amounts of waste. Coffee and its waste contain large amounts of chemicals many of which are highly toxic and none of which have a history of resistance in mosquitoes. Once in solution, coffee is brownish in colour, resembling leaf infusion, which is highly attractive to gravid mosquitoes. To anticipate the environmental issues related to the increasing popularity of coffee as a drink, and also to combat insecticide resistance, we explored the deterrence potentials of coffee leachates against the ovipositing and embryonic stages of the dengue vector, Aedes albopictus.

METHODS

In a series of choice, no-choice, and embryo toxicity bioassays, we examined changes in the ovipositional behaviours and larval eclosion of Ae. albopictus in response to coffee extracts at different concentrations.

RESULTS

Oviposition responses were extremely low when ovicups holding highly concentrated extract (HCE) of coffee were the only oviposition sites. Gravid females retained increased numbers of mature eggs until 5 days post-blood feeding. When provided an opportunity to oviposit in cups containing coffee extracts and with water, egg deposition occurred at lower rates in those containing coffee, and HCE cups were far less attractive to females than those containing water only. Females that successfully developed in a coffee environment preferentially oviposited in such cups when in competition with preferred oviposition sites (water cups), but this trait did not continue into the fourth generation. Larval eclosion occurred at lower rates among eggs that matured in a coffee environment, especially among those that were maintained on HCE-moistened substrates.

CONCLUSIONS

The observations of the present study indicate a pronounced vulnerability of Ae. albopictus to the presence of coffee in its habitats during the early phases of its life cycle. The observations that coffee repels gravid females and inhibits larval eclosion provide novel possibilities in the search for novel oviposition deterrents and anti-larval eclosion agents against dengue vectors.

Field evaluation of the response of Aedes albopictus (Stegomyia albopicta) to three oviposition attractants and different ovitrap placements using black and clear autocidal ovitraps in a rural area of Same, Timor-Leste

Known oviposition attractants or stimulants were compared, singly and in combination, using inexpensive autocidal ovitraps designed to trap emerging adults, in a rural area of Timor-Leste during the dry season. In this area, the dengue vector Aedes albopictus (Stegomyia albopicta) Skuse (Diptera: Culicidae) was abundant, but Aedes aegypti (Stegomyia aegypti) L. was not detected. The attractants were: (a) a compound found in Aedes eggs (dodecanoic acid); (b) components of nitrogen, phosphorous and potassium-based (NPK) fertilizer, and (c) infusions of discarded cigarette butts. A solution of ammonium phosphate and potassium nitrate was significantly more attractive to gravid Ae. albopictus than water only. Dodecanoic acid and cigarette butt infusions were not significantly more attractive than the control; however, they attracted various other Diptera and many non-culicid larvae developed in ovitraps in which these substances were used; thus, the presence of eggs or larvae of other species may have deterred Aedes oviposition. Significantly more Aedes eggs were found in ovitraps under vegetation than in ovitraps placed inside houses or against external walls. Clear-sided ovitraps in which black mesh was placed over a black ring floating on the water surface collected significantly fewer eggs than black ovitraps with identically placed mesh and rings.

Indirect effects of cigarette butt waste on the dengue vector Aedes aegypti (Diptera: Culicidae)

Despite major insecticide-based vector control programs, dengue continues to be a major threat to public health in urban areas. The reasons for this failure include the emergence of insecticide resistance and the narrowing of the spectrum of efficient products. Cigarette butts (CBs), the most commonly discarded piece of waste, also represent a major health hazard to human and animal life. CBs are impregnated with thousands of chemical compounds, many of which are highly toxic and none of which has history of resistance in mosquitoes. This study was performed to examine whether exposure to CB alters various biological parameters of parents and their progeny. We examined whether the mosquito changes its ovipositional behaviors, egg hatching, reproductive capacity, longevity and fecundity in response to CB exposure at three different concentrations. Females tended to prefer microcosms containing CBs for egg deposition than those with water only. There were equivalent rates of eclosion success among larvae from eggs that matured in CB and water environments. We also observed decreased life span among adults that survived CB exposure. Extracts of CB waste have detrimental effects on the fecundity and longevity of its offspring, while being attractive to its gravid females. These results altogether indicate that CB waste indirectly affect key adult life traits of Aedes aegypti and could conceivably be developed as a novel dengue vector control strategy, referring to previously documented direct toxicity on the larval stage. But this will require further research on CB waste effects on non-target organisms including humans.

Turning cigarette butt waste into an alternative control tool against an insecticide-resistant mosquito vector

Annually, 4.5 trillion cigarette butts (CBs) are flicked into our environment. Evidence exists that CB waste is deadly to aquatic life, but their lethality to the aquatic life of the main dengue vector is unknown. CBs are full of toxicants that occur naturally, during planting and manufacturing, which may act as larvicidal agents. We assessed Aedes aegypti vulnerability to Marlboro butts during its development. Overall, CBs showed insecticidal activities against larvae. At early phases of development, mortality rates were much higher in two CBs solution (2CBSol) and 3CBSol microcosms (MICRs). Larval survival gradually decreased with development in 1CBSol-MICRs. However, in great presence of CBs, mortality was high even for the late developmental stages. These results suggest that A. aegypti larvae are vulnerable to CB presence in their habitats, but this effect was seen most during the early developmental phases and in the presence of increased amounts of cigarette remnants. CB filters are being used as raw material in many sectors, i.e., brick, art, fashion, plastic industries, as a practical solution to the pollution problem, the observed butt waste toxicity to mosquito larvae open new avenues for the identification of novel insecticide products.