OUR iGEM JOURNEY BEGINS

The Issue of PAHs

Polyaromatic Hydrocarbons (PAHs) are a group of organic compounds consisting of multiple aromatic rings, known for their persistence in the environment and potential health risks. They are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances. Some PAHs, such as Benzo[a]pyrene, Naphthalene, Anthracene, and Chrysene, are particularly dangerous, leading to carcinogenic effects and other serious health issues. They are ubiquitous in air, water, soil, and sediments, and have been detected in food, consumer products, and human tissues with a wide range of biological toxicity (Adeniji et al., 2018).

Pyrogenic, petrogenic, and biological activities constitute the sources of PAHs, but precisely the point sources of pollution are both natural and anthropogenic emissions. Of which, the latter elicits the main drivers of PAH Pollution. PAH pollution is strongly deteriorating human health, along with other organisms across the planet due to its toxicity, persistence, and bioaccumulation potential (Marris et al., 2020).

The disease burden from PAH pollution is becoming more obvious, with a slew of new research finding a strong link between pollution levels and decreased life expectancy (Rengarajan et al., 2015; Tong et al., 2018; Yu, 2002). The global burden of PAH pollution, which contributes to an estimated 4 million deaths annually attributed to ambient air pollution, is deeply shocking to inter-governmental public health gains (Goshua et al., 2022).

Collective Efforts

Consequently, collective efforts should be geared towards developing a user-friendly that eliminates discrepancies in detection frameworks of PAH detection to eliminate the socio-economic factor as a deterrent from successful global efforts towards containment of toxic PAH pollution.

THE PROBLEM - NEED FOR FIELD ADAPTABLE SYSTEMS FOR PAH DETECTION

Gas Chromatography-Mass Spectrometry (GC-MS), which is expensive, time-consuming, and dependent on specialized expertise and hazardous reagents, presents a significant accessibility challenge especially in low resource settings. Limited of field-adaptable detection systems compound the difficulties faced in environmental monitoring and management. Seeking an appropriate analytical method for detecting PAHs attributes the success of PAH pollution efforts to using reliable detection techniques. Therefore the development of a user-friendly biosensor can not be a missed concept.

CONDUCTED RESEARCH AND DREW CONCLUSIONS

From our extensive data analysis of sample collections and scoring of relevant PAHs, pyrene and phenanthrene have stood out as particularly concerning PAHs, warranting focused attention. While other PAHs are also present and pose risks, we have chosen to concentrate on these two compounds for our  project.

OUR SOLUTION

We are focused on developing a specialized biosensor specifically designed for water samples, with an emphasis on detecting Pyrene and Phenanthrene. We intend for this targeted approach to be applied across various domains, including drinking water monitoring, industrial wastewater surveillance, agricultural water safety, natural water bodies assessment, and emergency response.

THE STRATEGY

We are using specific genes from Burkholderia sp. strain RP037 and Cycloclasticus P1 strain that respond to phenanthrene and pyrene respectively in water samples. The project emphasizes collaboration with relevant stakeholders, ensuring a cost-effective, community-engaged, and regulation-compliant approach. Looking to the future, the team has a vision for remediation that goes beyond mere detection. This includes the development of targeted treatment strategies, collaboration with environmental agencies for effective implementation, utilization of bioremediation techniques, and the integration of community-based solutions to address the root causes of PAH contamination. We intend for this targeted approach to be applied across various domains, including drinking water monitoring, industrial wastewater surveillance, agricultural water safety, natural water bodies assessment, and emergency response.

THE UNDERLYING MOTIVATION BEHIND OUR PROJECT

The Rise of PAHs in Aquatic Environments

The increase in PAHs, derived from fuels and incomplete combustion processes, has become more pronounced in recent years. In aquatic ecosystems, oil spills are a direct source of PAH pollution, often aligning with major shipping routes. The toxicological impact of accidental oil spills on marine environments is a serious concern, with petrogenic and pyrogenic sources of PAHs being predominantly artificial and significant contributors to environmental pollution.

The Deepwater Horizon Oil Spill: A Case Study

Between April and July 2010, the Deepwater Horizon Oil Spill became one of the most devastating incidents in the oil industry's history. Approximately 4.9 million barrels of crude oil were discharged into the Gulf of Mexico, causing widespread ecological damage.The crude oil contained toxic PAHs, which had catastrophic effects on the marine life in the region. Fish, benthic organisms, and marine vertebrates suffered from immunotoxicity, embryonic abnormalities, and cardiotoxicity. The liver, a vital organ, became a target for PAHs, particularly in bottom-feeding fish living in contaminated sediment.

Sensitivity in Teleost Fish Embryo

The teleost fish embryo is notably sensitive to PAHs at two distinct developmental stages. During early cleavage stages, PAHs disrupt normal signaling, leading to hyperdorsalized embryos that fail to hatch. The second sensitive period occurs during heart development, where PAHs cause abnormal heart development, cardiac edema, and arrhythmia, even at extremely low levels.

Impact on Diverse Species

Phytoplankton and phytobenthos, found in both marine and freshwater environments, exhibit a diverse range of sensitivities to PAHs. These organisms have the ability to accumulate, transfer, and even break down PAHs, reflecting their multifaceted interaction with these chemical compounds. A study involving Daphnia magna, a keystone species in aquatic food webs, revealed a high sensitivity to pyrene. Another study examined the toxic effects of PAHs on the earthworm species Eisenia fetida, comparing it with other invertebrates. The findings showed varying levels of vulnerability among different species, emphasizing the need to evaluate PAH toxicity across a broad spectrum of organisms. Moreover, the diverse reactions of different species to these compounds further complicate the understanding of their effects. Continued research and careful monitoring are essential to grasp the full scope of PAHs' influence on our delicate aquatic ecosystems and to develop strategies to mitigate their harmful effects.

PAHs and Micro plastics

In a recent study, researchers discovered the presence of microplastics in surface water, with high levels of Polycyclic Aromatic Hydrocarbons (PAHs) attached to them. This finding raises concerns, as the PAHs attached to the microplastics may exhibit toxicity to aquatic animals, potentially leading to harmful effects within the ecosystem. The study underscores the complex relationship between microplastics and PAHs, and the potential risks they pose to marine life.

CHALLENGES & OPPORTUNITIES

Sensitivity: Achieving high sensitivity of detection shall require specialized materials and design.

Selectivity: Ensuring selectivity over other PAHs or contaminants is a key challenge.

Integration with Nanomaterials: The use of nanomaterials like graphene or nanoparticles may enhance the performance of the biosensor for detection.