Persistent, bioaccumulative, and toxic chemicals in insects: Current state of research and where to from here?

Insects to the rescue? Insights into applications, mechanisms, and prospects of insect-driven remediation of organic contaminants

Traditional and emerging contaminants pose significant human and environmental health risks. Conventional physical, chemical, and bioremediation techniques have been extensively studied for contaminant remediation. However, entomo- or insect-driven remediation has received limited research and public attention. Entomo-remediation refers to the use of insects, their associated gut microbiota, and enzymes to remove or mitigate organic contaminants. This novel approach shows potential as an eco-friendly method for mitigating contaminated media. However, a comprehensive review of the status, applications, and challenges of entomo-remediation is lacking. This paper addresses this research gap by examining and discussing the evidence on entomo-remediation of various legacy and emerging organic contaminants. The results demonstrate the successful application of entomo-remediation to remove legacy organic contaminants such as persistent organic pollutants. Moreover, entomo-remediation shows promise in removing various groups of emerging contaminants, including microplastics, persistent and emerging organic micropollutants (e.g., antibiotics, pesticides), and nanomaterials. Entomo-remediation involves several insect-mediated processes, including bio-uptake, biotransfer, bioaccumulation, and biotransformation of contaminants. The mechanisms underlying the biotransformation of contaminants are complex and rely on the insect gut microbiota and associated enzymes. Notably, while insects facilitate the remediation of contaminants, they may also be exposed to the ecotoxicological effects of these substances, which is often overlooked in research. As an emerging field of research, entomo-remediation has several knowledge gaps. Therefore, this review proposes ten key research questions to guide future perspectives and advance the field. These questions address areas such as process optimization, assessment of ecotoxicological effects on insects, and evaluation of potential human exposure and health risks.

Spatial and temporal trends of 64 pesticides and their removal from Australian wastewater

Pesticides are necessary for the control of pest plant, fungi and insect species. After application, they may find their way into waste streams, such as municipal sewage, where their spatio-temporal distribution has not been well characterised. To further understand the spatio-temporal distribution and to evaluate potential sources and fate after treatment, 64 pesticides were analysed in matched influents and effluents of 22 wastewater treatment plants (WWTPs) from across Australia. The pesticides consisted of 30 herbicides and 8 herbicide metabolites or transformation products, 16 insecticides and 10 fungicides. The samples were 1084 24-hr composite samples pooled into 113 samples. Pools represented two influent and one effluent pools at each of 22 sites in 2019, as well as two pools per year from 2009 to 2021 for an 11-year long-term temporal trend at a subset of two locations. The total population served by the 22 sites was equivalent to ~41 % of the Australian population. Of the 64 pesticides, 25 were detected in influent, with highest influent concentrations up to 100 μg/L and effluent concentrations up to 16 μg/L for the herbicide 2,4-D. The total mass of pesticides was extrapolated to Australia, suggesting ~33 t of the targeted pesticides entered WWTP influent annually nation-wide, with 14 t emitted into effluents annually. Long-term trends varied by analyte and for carbendazim decreases over time, may be related to restrictions in use. Risk quotients (RQs) were calculated for 14 analytes in the effluent. 35 % had an RQ above one, indicating a potential environmental risk. Fipronil had the highest RQ (49) at Site 6. The population-normalized mass loads of pesticides were site-specific, and in some cases correlated with land use attributes suggestive of point sources. This reflects a need to better characterise sources to enable prevention, or possible pre-treatment of pesticide-containing wastewater entering municipal sewage streams.

Exploring the Occurrence of Organic Contaminants in Human Semen through an Innovative LC-HRMS-Based Methodology Suitable for Target and Nontarget Analysis

Understanding the potential impact of organic contaminants on male fertility is crucial, yet limited studies have examined these chemicals in semen, with most focusing on urine and blood. To address this gap, we developed and validated a robust LC-HRMS methodology for semen analysis, with a focus on polar and semipolar chemicals. Our methodology enables the quantitative (or semiquantitative) analysis of >2000 chemicals being compatible with suspect and nontarget strategies and providing unprecedented insights into the occurrence and potential bioaccumulation of diverse contaminants in this matrix. We comprehensively analyzed exogenous organic chemicals and associated metabolites in ten semen samples from Spanish participants collected in an area with a large presence of the chemical industry included in the LED-FERTYL Spanish study cohort. This investigation revealed the presence of various contaminants in semen, including plastic additives, PFAS, flame retardants, surfactants, and insecticides. Notably, prevalent plastic additives such as phthalic acid esters and bisphenols were identified, indicating potential health risks. Additionally, we uncovered previously understudied chemicals like the tire additive 2-mercaptobenzothiazole and specific organophosphate flame retardants. This study showcases the potential of our methodology as a valuable tool for large-scale cohort studies, providing insights into the association between contaminant exposure and the risk of male fertility impairments.

Risk factors of malaria transmission in mining workers in Muara Enim, South Sumatra, Indonesia

Eliminating malaria by 2030 is stated as goal three in the UN's Sustainable Development Goals (SDGs). However, malaria still remains a significant public health problem. This study aims to identify the factors determining malaria transmission in artisanal or small-scale miner (ASM) communities in three villages: Tanjung Agung, Tanjung Lalang, and Penyandingan, located in the Tanjung Enim District, Muara Enim, South Sumatra, Indonesia. Researchers conducted a cross-sectional study involving 92 participants from the study area. They used a logistic regression model to investigate the risk factors related to malaria occurrence. The multivariable analysis revealed that age (Adjusted Prevalence Ratio (APR) = 7.989 with 95% CI 1.724-37.002) and mosquito breeding (APR = 7.685 with 95% CI 1.502-39.309) were risk factors for malaria. On the other hand, higher education (APR = 0.104 with 95% CI 0.027-0.403), the use of mosquito repellent (APR = 0.138 with 95% CI 0.035-0.549), and the condition of house walls (APR = 0.145 with 95% CI 0.0414-0.511) were identified as protective factors. The current study highlights age and mosquito breeding sites as risk factors for malaria. Additionally, higher education, insect repellent use, and the condition of house walls are protective factors against malaria. Therefore, reducing risk factors and increasing protective measures through effective communication, information, and education are highly recommended to eliminate malaria in mining areas.

Reply to Letter to the Editor: Huang, M., 2022: Comments on "Persistent, bioaccumulative, and toxic chemicals in insects: Current state of research and where to from here?". Sci Total Environ. 838, 155624, and Corrigendum

In our recently published study in Science of the Total Environment, we used a systematic literature search to investigate the current state of research of persistent, bioaccumulative, and toxic chemicals (PBTs) and insects. We found a distinct increase of human, animal, and vertebrate publications related to PBTs in the early 1990s but did not identify a conclusive cause for this. In her Letter to the Editor, Huang (2022) offered an explanation for our result, and we have used her initiative to repeat our analysis with refined methodology. We present a corrected version of our original Fig. 1; importantly, though, our main finding, the general underrepresentation of insects in the research of PBTs, has remained the same. We conclude by addressing difficulties such as the reproducibility in literature searches and by discussing consequences of unequal resource distributions in science.

Recent Insight on Edible Insect Protein: Extraction, Functional Properties, Allergenicity, Bioactivity, and Applications

Due to the recent increase in the human population and the associated shortage of protein resources, it is necessary to find new, sustainable, and natural protein resources from invertebrates (such as insects) and underutilized plants. In most cases, compared to plants (e.g., grains and legumes) and animals (e.g., fish, beef, chicken, lamb, and pork), insect proteins are high in quality in terms of their nutritional value, total protein content, and essential amino acid composition. This review evaluates the recent state of insects as an alternative protein source from production to application; more specifically, it introduces in detail the latest advances in the protein extraction process. As an alternative source of protein in food formulations, the functional characteristics of edible insect protein are comprehensively presented, and the risk of allergy associated with insect protein is also discussed. The biological activity of protein hydrolyzates from different species of insects (Bombyx mori, Hermetia illucens, Acheta domesticus, Tenebrio molitor) are also reviewed, and the hydrolysates (bioactive peptides) are found to have either antihypertensive, antioxidant, antidiabetic, and antimicrobial activity. Finally, the use of edible insect protein in various food applications is presented.

Comments on "Persistent, bioaccumulative, and toxic chemicals in insects: Current state of research and where to from here?"

A recent study published in Science of the Total Environment conducted a systematic review of persistent, bioaccumulative, and toxic chemicals (PBTs) in insects using Web of Science Core Collection. Interestingly, a remarkable increase of human, animal, and vertebrate publications related to PBTs appeared in the early 1990s. Despite the authors' attempts to illustrate the anomalies from different perspectives, no rational explanation has been found yet. Quite interested in this abnormal phenomenon, we intend to join the academic discussion by pointing out some problems in the data retrieval and processing process in this review study and giving a more reasonable explanation for the surge of research publications in the early 1990s. Our new interpretations based on large-scale empirical data will help scholars make better use of this well-known and widely used database.