1.Population

The survey was distributed throughout Howard Community College via email lists, physical and digital posters, shared on Canvas through announcements and banners, and direct in-person solicitation of respondents. Both faculty and students over the age of 18 were allowed to participate. All respondents gave typed consent to participate in the survey and have their response data analyzed. All responses were given completely anonymously. As of March 11, 2026, 16 responses were collected.

2.Survey Design

Questions were meant to ascertain common pesticide use practices, including but not limited to exact chemicals used, season, frequency, knowledge, and personal feelings on their usage. Information was embedded into the questions to educate a participant as they progressed throughout the survey, with earlier questions on feelings being repeated at the end to determine if learning new information affected their answers. This was built in conjunction with the literature review process, which provided a look at the current factual knowledge on these substances to ground the qualitative and opinion-based questions of the survey.A significant portion of survey design was dedicated to the IRB process. Due to the involvement of human participants, several criteria had to be met for IRB approval. This included vetting participants to ensure they were over 18, that the survey be fully anonymous and collect no personal data, and for several clarifications to be made regarding the questions used.Both quantitative and qualitative data were collected from participants. Quantitative data primarily focused on usage habits, feelings, and assessments of knowledge. This used ranked choice questions as well as checkboxes and single choice selections. Qualitative data was gathered using open-ended questions meant to provide a wider range of depth to responses such as questions asking to elaborate on previous answers. The survey in its entirety can be viewed by following the QR code in Figure 1.

Figure 1: QR code link to the full pesticide-use survey

3.Literature Collection

The integrative literature review portion is meant to gather knowledge of pesticide effects on three species: humans, dogs, and mallards. As there are too many potential species to cover them, the reviewed species were narrowed down to these three in order to maintain relevancy toward the general population while also providing a focal point into how the side effects of pesticide usage vary between animals. Humans were chosen due to the amount of easily available literature and being universally relevant while dogs were chosen as another species of mammal that is more likely to be in direct contact with pesticides through various means such as walking on grass where pesticides have been applied, drinking rainwater and eating substances off the ground. Mallards are a species of interest because they represent how neonicotinoids and pyrethroids may affect birds, particularly waterfowl. As mallards prey on fish, pesticide effects on fish may be reflected through them. All these animals are present in Howard County, making them directly relevant to the area surveyed.
Mallards were also chosen for their significant representation within studies of pesticide effects on bird life. Articles used in this review were sourced through Pubmed, JSTOR, and the Biological Sciences Database. Key terms for initial searches included “pesticides”, “insecticides”, “neonicotinoid”, “herbicide”, “health impacts”, “human health”, and “safety”. After narrowing down to the two classes and three species, they became “neonicotinoid”, “pyrethroid”, “anas platyrhynchos”, “common mallard”, “humans”, “dogs”, and “canis familiaris”.
Most literature left off at the idea of remediation and substance interactions. While there were specialized papers suggesting integrative pest management and microbial-based remediation strategies, it seems that the literature is not yet settled on the best ways to combat areas already over-polluted by pesticide usage. In addition to this, there are limited resources to suggest how these substances may interact with each other within the body.

 

Results and Discussions

1.Survey
Data on pesticide usage from 16 respondents were collected. Due to the limitation on participant numbers, results may change drastically as research progresses. The demographics included were Howard Community College faculty and currently enrolled students. All participants were 18 years or older. Questions without included figures can be found by following the link at Figure 1. Participants were not questioned about age, ethnicity, or any personally identifying information.

 

1.1 Familiarity
Figures 2-6 present a subset of survey questions and their results. This includes familiarity with either substance, reported feelings of knowledge, reported stance on usage of the substances, pet ownership demographics, and personal concerns about risks associated with usage. The majority (81%) of respondents had never heard of neonicotinoids or pesticides. Only 6% reported knowledge of pyrethroids, and 13% had heard of both (Figure 2). No respondents recognized only neonicotinoids. No question differentiated between knowledge on just neonicotinoids or pesticides.

Figure 2: Respondents’ reported familiarity with neonicotinoid and pyrethroid pesticides at the beginning of the survey

Most surveyed individuals, 69%, initially reported feeling that they knew “nothing” about either pesticide while 13% reported knowing “not much” (Figure 3). The last three answers were evenly spread with 6% of people claiming to know an “average amount”, another 6% knowing “more than most people”, and a final 6% knowing “a lot more than most people” about neonicotinoids and pyrethroids.

Figure 3: Respondents’ feelings of knowledge on pyrethroid and neonicotinoid pesticides before and after completion of the survey

Upon being reassessed at the end of the survey, the lowest percentages jumped from just 6% to 44% for “average” knowledge, 19% for “more than most people”, and 13% for “a lot more than most people”. Feeling of knowing “not much” remained static at 13%, while feelings of knowing “nothing” dropped to 13% (Figure 3).

 

1.2 Pet Ownership

Figure 4: Number of pets owned by respondents

With regard to pet ownership, 43.8% of individuals surveyed reported having no pets, while 37.5% owned one, and 18.8% owned three or more. No participants reported having only two pets.

 

1.3 Personal Feelings

Figure 5: Respondents’ personal stance on neonicotinoid and pyrethroid pesticide usage before and after completion of the survey 

 

While 38% of respondents originally stated that their feelings towards these pesticides were “very negative” or “neutral”, with 25% as “somewhat negative”, the majority of respondents changed to feeling “very negative” (31%) and “somewhat negative” (44%) at the end (Figure 5). No respondents felt somewhat or very positive about their use at either point in the survey.

In Figure 6, participants showed fairly distributed feelings of worry about potential side effects from pesticide usage. 25% of participants reported never or rarely worrying, while 13% worried “sometimes”, and 19% felt this way periodically or frequently (Figure 6). This question was asked towards the end of the survey, but before the reassessment of feelings and knowledge.

Figure 6: Respondents’ reported frequency of anxiety about experiencing negative side effects from pesticide usage

Participants’ opinions on pesticide usage were largely informed by fear of insects. They were allowed to choose multiple answers for this section, with 31.3% crediting this to fear or dislike of insects, and 25% citing invasive species control. 12.5% of respondents reported not seeing any harm in it or finding it hard to grow plants without them, and the lowest percentage (6.3%) did so to have a well-maintained lawn. Eight respondents listed their own custom reasons, including: seeing pesticides as “cancer causing and kills insects”, that “they suck and are terrible for the environment”, and that they were “generally against pesticides because they kill/harm insects/animals”.

After the survey, most respondents reported that they had interest in finding alternatives to neonicotinoid and pyrethroid pesticides (81.3%), but only 50.0% felt that they would be able to pursue this interest, with those who couldn’t being several of the same participants who reported that parents/relatives, pest control companies, and neighbors were responsible for pesticide application.

 

1.3 Frequencies of Use and Association

Commonly used neonicotinoids were acetamiprid, at 31.3% of participants whereas 12.5% each (25% in all) used imidacloprid and thiamethoxam. Only 12.6% of participants used pyrethroids, naming cypermethrin and deltamethrin with 50% of participants using this substance on their lawns, 18.8% inside their homes, and 12.5% in personal gardens. Most common reasons given for pesticide application were insect control (56%) and beautification (25%). Most substances were applied by parents or relatives rather than the respondents themselves; only 12.5% personally applied them. Of the study’s participants, 25.0% applied them year-round while the majority (68.8%) applied them during the summer (18.8% applied in the summer and one other select season as well; which splits into 12.3% in spring and 6.5% in fall). 18.8% had them applied during the spring and no participants had them applied solely in the winter. As participants could select multiple options, this does not add up to 100%.

Of the survey respondents, the majority, 50% never frequented areas treated with pesticides, nor did their pets, while 31.3% frequented treated areas “rarely, if ever”. Among the 18.8% of participants who responded that they were often exposed to treated areas, two-thirds (12.5%) reported that they did so “at least once a month”, and the other third (6.3%) reported that they did so “at least once a week”. Reports of “never” worrying and worrying “rarely” about side effects from pesticide usage were tied at 25% each, with 12.5% worrying “sometimes”, and 18.8% worrying “periodically” or “frequently”. Those who reported low levels of worry had common reasons such as the idea never crossing their mind, that this had not been a concern to them prior, or because they did not feel they were personally affected by this. Those who reported their worry as being “frequent”, however, often listed their reasoning as fears of long-term effects such as cancer or climate change. Participants reporting “periodic” worry cited worry over the safety of home-grown vegetables treated with pesticides, and that they avoided spraying pesticides where their dog plays.

 

2. Survey Discussion

Other questions led to unexpected results. Very few participants reported being familiar with neonicotinoids despite the prevalence of older anti-neonicotinoid campaigns such as Save the Bees. This may be due to the age demographic of this survey and could reflect the generational difference in how information is sourced. As many respondents are college students, it is possible that many were too young during this informational campaign to properly remember it. Additionally, many respondents owned pets though few of them reported concern about pesticide effects, which signals a general unawareness about the risks that pesticides have for animals. This may reflect a need for continued educational efforts among younger generations.

While Maryland has passed neonicotinoid restrictions such as the Pollinator Protection Act of 2016 which requires a specialized license to apply neonicotinoids, many survey participants still used more neonicotinoids than pyrethroids [18]. This suggests that the current restrictions may not be fully effective. Those who reported high concern and negative feelings on pesticide usage typically did not use these substances themselves, while those who felt neutral towards them did. Respondents’ usage of pesticides for beautification, lawn care, and for fear of insects was largely expected. It is somewhat unusual that so few respondents used them for agriculture or for gardening as there is a rural portion of the county, however it is possible that no one in this area responded to the survey. The low number of respondents is a significant limitation to the conclusions that can be drawn from them. It is possible that results would drastically change given more participants.

As HCC is in the largely suburban community of Howard County, participants may also use pesticides to meet HOA standards. Traditional grass lawns have been known to be unfriendly towards the ecosystem: about 30% of American water usage goes to lawn maintenance, an estimated 50% of which is wasted through improper irrigation [8]. Monoculture lawns greatly limit the food sources available to local pollinators, and monoculture farmland has been shown to experience an overall increase in pest species of insects when compared with farms containing diverse mixtures of crops, suggesting lack of plant variety contributes to pest prevalence, which in turn may lead to more pesticide usage [29]. Despite these factors, a well-kept grass lawn is often a requirement within American HOAs.

 

2.1 Survey Design Considerations

Several potential conflicts arose from unclear wording and failure to provide all possible reasons on limited choice questions, resulting in participants feeling forced to respond in a way that does not truly reflect their habits. While the survey was intended to be answered only by participants who used any pesticides at all–the marketing and recruitment materials stated as much—some participants still answered despite not being pesticide users, resulting in the survey focus having to be tweaked in order to properly reflect this. For instance, many participants who did not use any of these substances selected “Other/Unsure” in lieu of an option that suited them when asked about which classes they owned. It would be in this study’s best interest to more clearly and consistently reiterate its intended demographic or, alternatively, to provide more options to account for all possible responses. Many questions are based on relative answers, such as asking a participant to compare their knowledge to the average person, which reflects on the subjective nature of quantitative questions.

 

3. Literature

Table 1: Comparison table of neonicotinoids, pyrethroids, contrasting their method of action, toxicity, pollution, and other notable effects.

 

Across pesticide class and species, risks of cancer and reproductive issues increased alongside usage rates. Likewise, neonicotinoid pesticide usage was found to have deleterious effects on all three species’ health. General results can be viewed in Table 1.

Neonicotinoids bind to nicotinic acetylcholine receptors in an insect’s neurons [12, 19]. This overloads the cell by continually activating the receptor signaling, which leads to shutdown of their central nervous system, causing paralysis and subsequent death [12, 19, 28]. Neonicotinoids cause oxidative stress to mitochondria, endoplasmic reticulum (ER), and to the DNA, damaging both genetic information and inducing irregular cell behaviors, which makes these substances both a cytotoxin and genotoxin [12]. They are far less lethal to vertebrates, but are still toxic [12, 19].

Pyrethroids are currently grouped by symptoms of their poisonings in vertebrates, determined by whether the substance contains an alpha-cyano group or cyano group [1, 25]. Type I pyrethroids, the most popular being allethrin, permethrin and resmethrin, induce tremor-type (“T”) syndrome, which manifests in bodily tremors, seizures, lack of coordination, hypersensitivity, and aggression [1, 16]. Type II pyrethroids, commonly administered as deltamethrin and cypermethrin, induce choreoathetosis-salivation (“CS”) syndrome, which causes a myriad of muscular side effects such as involuntary tremors, lack of coordination, and writhing movements as well as salivation and hyperactivity [1, 25]. The review “Current Research on the Safety of Pyrethroids Used as Insecticides” considers their effects as toxic to the kidneys, liver, cardiovascular and immune systems as well as to a cell’s genetic structure [10, 25].

Despite their low short-term toxicity in these three species, pyrethroid pesticide usage has been implicated in many chronic conditions. By functioning as a genotoxin, pyrethroids are a carcinogenic substance even in low doses. This risk is most prominent in cases of long-term low-dose exposure. Pyrethroids are highly lipophilic, which allows for long-term accumulation within organic tissues. When substances stored in fat are broken down suddenly by things such as weight loss, this triggers them to suddenly re-enter the body. While these are usually cleared by the body without issue, large enough quantities can cause symptoms associated with poisoning. A study into the hydrolytic metabolism of pyrethroids within rats and humans found that enzymes in the liver were responsible for breaking down pyrethroids and speculated that lipases from the pancreas may also contribute [7]. This may be a cause for concern in high-risk individuals such as those who are exposed to unusually high concentrations of pesticides and those with reduced hepatic or pancreatic function.

 

3.1. Humans

Concentrations of neonicotinoids have been discovered within human urine, breastmilk, and spinal fluid [16, 24]. Several studies have suggested possible dangers for humans due to neonicotinoid exposure. Some are broader: implicating general pesticide exposure in bringing about similar incidences of cancer as with smoking, associating schoolyard pesticide usage with low-severity chronic illnesses in children, and linking county-level insecticide use with an increase in local infant mortality rates [2, 10, 11,]. However, recent studies have brought an additional level of clarity to the human-specific effects of neonicotinoid exposure.

A rodent study done by Sass et al contributes to the growing body of research suggesting that neonicotinoids may cause neurotoxic effects in humans. As an agonist to nicotine, it often induced similar effects to nicotine within the brains of rats: shrinkage of brain tissue and of the corpus callosum and caudate-putamen areas of the brain (which has been linked to ADHD in humans) and reduced startle responses [24]. Nearly all rats exposed to neonicotinoids in-utero saw diminished brain weight and volume, indicating loss of neural cells. Rats exposed to acetamiprid and imidacloprid in-utero have continually been shown to lose brain cells at higher rates while suffering a decreased ability to form new neurons in the hippocampus [24]. However, unlike nicotine, neonicotinoids cannot cross the blood-brain barrier [16]. These line up with findings on the influence of nicotine in rat brains. Nicotine and neonicotinoids act upon the same substrate, acetylcholine receptors, which are thought to influence learning and formation of memories. Neonicotinoids have also been shown to desensitize nicotinic acetylcholine receptors, causing them to require higher concentrations of neurotransmitters in order to fire [16, 24]. While the lower affinity of neonicotinoids to mammal nicotinic acetylcholine receptors makes it highly unlikely to have the same toxicity as nicotine, studies such as these suggest it is possible that they retain some of the same effects [24].

Studies following neonicotinoid effects on both humans and model animals have shown a variety of toxic effects across different bodily systems. These include the nervous system, intestines, lungs, liver, breast, kidneys, pancreas, heart, and gonads [16]. Rats and mice dosed with neonicotinoids have additionally been found to suffer thyroid lesions and atrophy of the retina [12]. Across all of these organs, neonicotinoids were found to induce cellular, mitochondrial, DNA damage, and apoptosis. By inducing cellular stress on the nervous system, cells become more easily damaged; when neonicotinoids are metabolized and lose their nitrate, they gain affinity for mammalian nicotinic acetylcholine receptors, allowing them to accumulate, which can cause inflammation of the central nervous system (CNS) [16]. Other notable neonicotinoid effects include the altering of gut microbiota, calcium overload, reduction of mitosis and certain enzymes within the liver, altering hormone production, and mimicking estrogen within the breasts, leading to an increase in incidence of breast cancer [16].

While the human risks resulting from pyrethroids remain low compared to other classes of pesticides such as DDT, and acute toxicity is considered a negligible risk, several studies have reviewed possible side effects from both short and long-term usage of pyrethroids. A 2023 literature review conducted by Ahamad & Kumar provides an overview of many symptoms and studies associated with pyrethroid poisoning. Most cases of this type of poisoning in humans lead only to lack of appetite, nausea, dizziness and headaches. However, more severe instances of pyrethroid poisoning lead to the symptoms concurrent with “T” or “CS” syndrome according to the class of pyrethroid in question. Poisoning from both classes can result in loss of consciousness, convulsions, a comatose state, and death [1].

As noted in the article by Ahamad & Kumar, certain pyrethroids caused hepatocellular tumors and an increase in lung adenocarcinomas in rats, a common model organism for humans [1]. As a genotoxin, pyrethroid pesticides build up oxidative stress in cells that results in the alteration of all cellular components, such as DNA, RNA, and other proteins found within cells [1, 25]. This makes them a carcinogenic substance. Pyrethroids have been shown to accumulate in cell membranes, where transport proteins may be modified by their presence [25]. This is a trait likely shared by all pyrethroids due to their lipophilicity.

Ahamad & Kumar additionally point out the possibility in studies for long-term exposure to pyrethroids to degrade sperm quality and count [1]. These studies have linked high urinary quantities of pesticide to increased levels of blood luteinizing and follicle-stimulating hormone [1]. These hormones work in conjunction to stimulate growth and development of an individual’s sexual organs as well as secondary sex characteristics such as breast development, bodily hair growth, and regulation of the menstrual cycle [5]. However, the research on pyrethroids’ impacts on human reproductive systems needs to be further refined.

Current literature on pyrethroids urges caution around pesticide exposure for pregnant or nursing parents. A review by Holynska-Iwan and Szewcyzyk-Golec suggests that children and pregnant people are at much higher risk for pyrethroid penetration, as pyrethroids have been found in human breastmilk [1, 25], which provides an oral route for pesticides in newborns. This is noteworthy, as in 2018 the US EPA re-classified pyrethroids to be a likely carcinogen when ingested [25].

Some research has correlated pyrethroid usage to neurological illness in addition to the toxic effects on the cardiovascular and immune systems, liver, kidneys, and cell structure [1, 15]. This includes a correlation between general pesticide exposure of newborns and incidence rates of ASD and other developmental delays [1]. Effects of pyrethroids on children are further described in a longitudinal study assessing pesticide-related illnesses in children with the amount and type of pesticides used at schools [2]. Alarcon et al. found that insecticide usage was commonly associated with illness, the majority of which were low-severity gastrointestinal or respiratory illnesses, with 6% of insecticide-related illness connected to pyrethroids and 18% to pyrethrins [2].

 

3.2. Domestic Dogs

According to the 2025 American Pet Products Association (APPA) Industry Statistics, 68 million Americans own dogs [4]. Dogs are more likely than the average human to come into adverse contact with pesticides through self-grooming, walking into treated areas, and ingestion of unknown substances. From 2017-2019, the Poison Control Center of Milan found pesticides to be one of the most common sources of household animal poisoning alongside pharmaceuticals [5]. Ingestion and contact with pesticides are quite common for dogs, but this raises further health concerns. There have been few studies on this topic, but reasons to continue research in this area are provided in older papers such as an epidemiological study that found dog bladder cancer rates to increase alongside topical insecticide use [22]. A 2012 study of Canine Malignant Lymphoma (CMS) compared its occurrence in domestic dogs alongside use of flea control products, lifestyle decisions, and lawn care products. They found that, overall, CML cases rose the most alongside frequent usage of professionally applied pesticides [27]. While they did not break down these categories beyond pesticide, herbicide, fungicide, rodenticide, insect growth regulator, and fertilizer, and therefore do not necessarily correlate with pyrethroids or neonicotinoids specifically, the results of this study should be taken as a sign that more specific scrutiny may be necessary.

 

3.3. Common Mallards

A meta-analysis published in 2024 found that neonicotinoids likely harmed all aspects of bird life, ranging from food availability to reproduction [19]. This result was felt most drastically in agricultural areas. While neonicotinoids may be expected to carry the most harm to birds that eat seeds, as those are the most likely to come in contact with pesticide-treated material, current studies suggest that the effects of neonicotinoids are felt more strongly throughout the food chain than previously expected [12, 19]. A Canadian study published in 2010 showed a startling decrease in North American insectivorous bird populations, reflecting the global decline of insect species, which has been linked to overuse of pesticides [21]. Many species, such as birds of prey, feel indirect effects through the food chain as substances accumulate in their bodies from preying on animals directly exposed to pesticides [19]. As omnivores, mallards subsist off both plants and animals, with the meat-based part of their diet consisting mostly of insects and fish. This exposes them to toxins from both contaminated animals, treated plants and seeds, and the watersheds in which they spend most of their time. As neonicotinoids dissolve readily in water and soil, they may pollute larger areas for longer than typically expected, with some studies finding that they can persist in soils for up to 19 years under the right conditions, allowing them to continue to be absorbed into plants, which are then absorbed up through the food chain [19].

Additionally, indirect effects may be felt not through direct absorption but through loss of habitat and prey, which is a cause for concern with mallards as neonicotinoids’ targeting of insects leads to reduction in a primary food source [12]. A meta-analysis on impacts of neonicotinoid exposure on reproduction, health, and behavior found the negative effects to be the most pronounced, with many symptoms related to poisoning such as weight loss, anemia, malnutrition, reduced food intake, as well as reductions in reproductive functions such as egg-laying rates, sperm density, and eggshell thickness [19]. This study also found a number of neurobehavioral side effects for birds, especially those related to migratory behaviors, observing that migrating birds who received a dose of imidacloprid became unable to orient themselves for up to two weeks after [19]. This is of importance to mallards as they typically migrate from the Gulf Coast to the Northern US & Canada. Direct effects on bird life have been studied for some time now; however, there is limited data on their effects on waterfowl such as mallards. Considering the important role of waterfowl in the ecosystem, further study may be prudent.

Compared to previously common pesticides such as DDT and organophosphates, all of which caused significant reproductive harm to birds, pyrethroids carry much less innate risk [28]. However, this perception of pyrethroids as less risky has led to frequent overuse and pollution. While the majority of harm is indirect, as it is with neonicotinoids, through destruction of their food chain, several studies have shown a direct link to poisoning and reproductive harm in the common mallard [12, 23]. A 2010 study by Parsons et al found that many rice fields frequented by waterfowl had significant pyrethroid concentrations, with seed-eating invertebrates accumulating high levels of pesticide that would then lead to disproportionate death by poisoning in waterfowl [23]. Migratory birds in the late spring faced the highest risk of pesticide exposure [23].

 

Conclusions and Future Directions

In conclusion, neonicotinoids and pyrethroids have seen continued use in the HCC community. Neonicotinoids, despite attempts to curtail their usage, continue to be frequently used and manufactured within the United States. Pyrethroids have become a popular pesticide for their efficacy and low short-term toxicity in mammals. While more participant data is necessary to draw scientifically valid conclusions, current results suggest that these substances and their effects are not fully understood by the general HCC community, as many respondents had no knowledge of either pesticide. An improvement to the survey could be to poll on identifying information such as age demographic, social class, and other demographics to see how results may be skewed along group lines. Differentiation between knowledge on just neonicotinoids or just pyrethroids would also be a prudent change. Additionally, reported negative feelings increased alongside reported feelings of knowledge after they took the survey, as did desire to change pesticide use habits, suggesting that either pesticide may not be used as widely given more knowledge. Questions regarding concern or worry about use of pesticides could be enhanced by being asked before and after being given additional information in the same way that questions surrounding general feelings of knowledge were posed. Increased educational campaigns to address this lack of awareness may improve the local health of people, animals, and the general ecosystem. A focus on education surrounding both short-term and long-term side effects of neonicotinoid and pyrethroid pesticide usage on people, their pets, and general wildlife may help to inform people’s usage of lawncare chemicals; while the literature surrounding their effects is somewhat robust, this knowledge seems to have mostly failed to reach the broader population. The strong increase in desire to find alternatives to pesticide use after exposure to relatively small amounts of information on their side effects suggests that increased attempts to reach the public may be beneficial to the broader HCC community.

 

Acknowledgements

Special thanks to Cheryl J. Campo for helping to manage and facilitate this project, to those in HCC’s PROD office who helped review it, and to all the survey respondents who took part in the study.

Contact: irene.allbritton@howardcc.edu

References