Microplastics Exposure Routes and Toxicity Studies to Ecosystems: An Overview

Christian Ebere Enyoh,Leila Shafea,Andrew Wirnkor Verla,Evelyn Ngozi Verla,Wang Qingyue,Tanzin Chowdhury,Marcel Paredes 환경독성보건학회 2020 환경독성보건학회지 Vol.35 No.1

Microplastics (MPs) are now ubiquitous in global ecosystem, therefore all biota is at risk of exposure and potential toxicity. In this study, we presented an overview of information based on literature concerning exposure to MPs and the toxicity of such exposure. Currently, four major routes of exposure have been identified including entanglement, contact, ingestion and inhalation. Humans maybe the most exposed organism because they are at the peak of the food chain. Toxicology effect to marine and freshwater organisms are classified based on exposure dosage as either high (mortality, decreased reproductive output, organ damage) or low (changes in behavior with time). On plants, reports have shown that MPs exposure can affect negatively the growth and depending on exposure concentration and types of MPs and oxidative activities. However, effects on plants maybe short-term and transient. Although, toxicity studies regarding human are still ongoing as per reports, plants and animals are still scantly studied. Animal toxicity studies have widely used D. magna as model specie. MPs pollution may have a knock-on effect on trophic structure and functioning of ecosystems by affecting the base of the food chain. We concluded by identifying the gap in knowledge and give recommendations for future research.

Macrodebris and microplastics pollution in Nigeria: first report on abundance, distribution and composition

Enyoh Christian Ebere,Verla Andrew Wirnkor,Verla Evelyn Ngozi,Ihenetu Stanley Chukwuemeka 환경독성보건학회 2019 환경독성보건학회지 Vol.34 No.4

The abundance, distribution and composition of marine debris ( > 5 cm) and small microplastics (11 μm) from five rivers in South Eastern Nigeria was investigated. This study provided the first assessment of the type and quantity of marine litter and microplastics in Nigeria. A total of 3,487 macrodebris items/m² were counted with the following distribution: plastics (59%), metal (10%), cloth (7%), paper/cardboard (7%), rubber (7%), glass/ceramics (5%), medical and agro-based waste (3%), and wood (2%). The cleanliness of the river assessed with clean coast index ranged from “very clean” to “extremely dirty”. Microplastics abundance ranged from 440 to 1,556 particles/L, with high accumulation at downstream. Fragment shape was most abundant while fiber and film followed. The distribution of plastic types was PET (29%), PE (22%), PVC (16%), PP (14%), and others (6%). Significant relationship was found between the total abundances of microplastics and different macrodebris groups suggesting that microplastics were abundant in areas where the macrodebris abundance was high. Our results provide baseline information for future assessments. Management actions should focus on input prevention including proper waste management, recycling of plastics, and strict penalties for illegal dumping of wastes.

Preliminary characterization and probabilistic risk assessment of microplastics and potentially toxic elements (PTEs) in garri (cassava flake), a common staple food consumed in West Africa

Christian Ebere Enyoh,Qingyue Wang,Mominul Haque Rabin,Rasheed Oluwafemi Bakare,Joseph Longji Dadiel,Wu Shangrong,Senlin Lu,Ifenna Ilechukwu 환경독성보건학회 2023 환경독성보건학회지 Vol.38 No.1

Monitoring and modeling of heavy metal contents in vegetables collected from markets in Imo State, Nigeria

Beniah Obinna Isiuku,Christian Ebere Enyoh 환경독성보건학회 2020 환경독성보건학회지 Vol.35 No.1

Vegetable consumption is one major exposure route of heavy metals to humans, but few data exist for Imo State, Nigeria. We assessed the contamination levels and associated health risk of cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in vegetables (Telfairia occidentalis, Pterocarpus mildbraedii, Gongronenina latifolium and Vernonia amygdalina) that are consumed frequently from markets (n=16) in three zones of Imo State, Nigeria. After wet-digestion of samples, the supernatant were analyzed using atomic absorption spectrophotometry. The mean concentrations in the four vegetables ranged from 0.006±0.003 mg/kg to 0.011±0.007 mg/kg for Cd, 0.064±0.012 mg/kg to 1.225±0.226 mg/kg for Co, 10.711±1.968 mg/kg to 25.088±13.975 mg/kg for Cu, 0.062±0.013 mg/kg to 0.307±0.210 mg/kg for Ni, 0.006±0.005 mg/kg to 0.012±0.002 mg/kg for Pb and 63.55±4.055 mg/kg to 104.126±24.080 mg/kg for Zn. Except for Zn, all heavy metals in the various vegetables were below the joint standard of Food and Agriculture Organization and World Health Organization. Although, overall load of heavy metal was very low, Zn had the highest contamination factor in vegetables. Heavy metals concentrations in vegetables generally showed low to high variations and statistically different (p<0.05). Average daily intake was below the provisional tolerance limit except for Zn. The target hazard quotient of metals in vegetables for both children and adults were below 1, indicating no potential risk to the public. Overall, heavy metals hazard index were below 1, indicating acceptable level of non-carcinogenic adverse health effect. However, potential multi-element contamination from ingestion is possible as revealed by the correlation profiling of heavy metals.

Computer-aided Degradation Susceptibility Study of Crude Oil Compounds at Bacillus subtilis Protein Target

Ijeoma Akunna Duru,Chidi Edbert Duru,Christian Ebere Enyoh,Haruna Isiyaku Umar 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.3

Certain bacteria and fungi have been associated with the oxidative degradation of hydrocarbons and hydrocarbon derivatives in soil and water contaminated by crude oil spilling in these ecosystems. The binding affinity of hydrocarbons and hydrocarbon derivatives in a crude oil sample on the cysteine dioxygenase of Bacillus subtilis was studied using computational methods. The study was aimed to validate the claim of the efficient use of this organism in crude oil remediation and to determine the selectivity of the compounds in the crude by this bacterium enzyme. The compounds in the studied crude oil sample were identified by gas chromatography-mass spectrometry. Straight chain hydrocarbons were the least selected class of compounds with binding free energy ranging between −2.9 kcal/mol to −3.1 kcal/mol. The straight-chain hydrocarbon derivatives containing carbonyl and hydroxyl groups formed the middle class of compounds selected by the enzyme with binding free energy ranging between − 3.3 kcal/mol to −3.7 kcal/mol. The best binding free energies (−3.8 kcal/mol to −5.1 kcal/mol) were obtained with the poly-branched hydrocarbons and the cyclic compounds. The amounts of the poly-branched and cyclic compounds in the crude oil sample suggested that cysteine dioxygenase of B. subtilis would show about 28 % efficiency in the bioremediation of environments polluted by crude oil of this composition.

Microplastics from degradation of tires in sewer networks of the city of Riobamba, Ecuador

Marcel Paredes,Rafaela Viteri,Tito Castillo,Cristian Caminos,Christian Ebere Enyoh 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.5

Microplastics are small synthetic particles that come from petroleum derivatives, are difficult to degrade and their origin is found in industrial activity and domestic consumption, even in tires. The presence of small particles (0.1 μm to < 5 mm) of plasticizer Bis (2-ethylhexyl) phthalate (DEHP) and synthetic rubber, which due to their size and origin are called microplastics. The friction occurs between the asphalt in contact with the tires of cars generate the detachment of small residues of it, these residues come to contain a DEHP element. Simple residual water samples were carried out in the different sewage collectors in Riobamba city, 250 mL of each of these samples were filtered using vacuum suction equipment, to then examine the filters with a visual microscope. Obtaining as a result that 80% of the samples taken and analyzed in the laboratory contain the clear presence of DEHP plasticizer from the friction of tires (confirmed by the Principal Component Analysis) with the asphalting of the streets of the city of Riobamba, and that only 20% of the samples analyzed do not present DEHP plasticizer of this type, generating a medium risk for the health of humans and aquatic animals in the sector.

Blocking the interactions between human ACE2 and coronavirus spike glycoprotein by selected drugs: a computational perspective

Chidi Edbert Duru,Haruna Isiyaku Umar Umar,Ijeoma Akunna Duru,Uchechi Emmanuela Enenebeaku,Lynda Chioma Ngozi-Olehi,Christian Ebere Enyoh 환경독성보건학회 2021 환경독성보건학회지 Vol.36 No.2

The coronavirus disease of 2019 (COVID-19) has become a global pandemic with rapid rate of transmission and fatalities worldwide. Scientists have been investigating a host of drugs that may be rechanneled to fight this malaise. Thus, in this current computational study we carried out molecular docking experiments to assess the bridging potentials of some commercial drugs such as chloroquine, hydroxychloroquine, lopinavir, ritonavir, nafamostat, camostat, famotidine, umifenovir, nitazoxanide, ivermectin, and fluvoxamine at the interface between human ACE2 and the coronavirus spike glycoprotein complex. This is aimed at ascertaining the ability of these drugs to bridge and prevent the complexing of these two proteins. The crystal structure of human ACE2 and the coronavirus spike glycoprotein complex was retrieved from protein database, while the selected drugs were retrieved from PubChem data base. The proteins and drugs were prepared for docking using Cresset Flare software. The docking was completed via AutoDock Vina module in Python Prescription software. The best hit drugs with each receptor were selected and their molecular interactions were analyzed using BIOVIA’s Discovery Studio 2020. The best hit compounds on the human ACE2 were the lopinavir (-10.1 kcal/mol), ritonavir (-8.9 kcal/mol), and nafamostat (-8.7 kcal/mol). Ivermectin, nafamostat, and camostat with binding energy values -9.0 kcal/mol, -7.8 kcal/mol, and -7.4 kcal/mol respectively were the hit drugs on the coronavirus spike glycoprotein. Nafamostat showed a dual bridging potential against ACE2 and spike glycoprotein, and could therefore be a promising lead compound in the prevention and control of this disease.

Biomonitoring of concentrations of polycyclic aromatic hydrocarbons in blood and urine of children at playgrounds within Owerri, Imo State, Nigeria

Verla Andrew Wirnkor,Verla Evelyn Ngozi,Chigbo Medo Ajero,Lele Kelechi Charity,Okechukwu StellaMaris Ngozi,Enyoh Christian Ebere,Amaobi Collins Emeka 환경독성보건학회 2019 환경독성보건학회지 Vol.34 No.4

Polycyclic aromatic hydrocarbons (PAHs) exposure is among the leading air pollutants associated with diverse adverse health effects due to their persistent, bio-accumulative and toxic characteristics. Children are most affected by these pollutants, yet studies directly related children to these pollutants are scarce in Nigeria. In this study, blood and urine from 36 children between the ages 4-14 years were collected as per sterile procedures by a licensed phlebotomist from the antecubital fossa into BD vacutainer tubes® while a midstream urine sample into acid-washed 120 mL BD vacutainer urine cups and stored in refrigerator at –4˚C for 6 hours, then each 5 mL was extracted with 10 mL of pentane and analyzed for 15 PAHs using GC-MS. Results revealed that PAHs concentrations (53.48 to 70.8 μg/dL) in blood was lower than in urine (94.98 to 115.04 μg/dL). Mean values had no significant (p>0.5) differences between schools, possibly due to the fact that all schools were experiencing similar anthropogenic disturbances. At 5% level of significance, positive and strong correlationships (r=0.83, r=0.73) were observed for fluorene-fluoranthene (FLa) and benzo (a) anthracene-FLa respectively in blood samples. Two and three rings PAHs had generally low concentrations in both blood and urine. Despite being the most distributed compound, the concentration of dibenzo (a,h) anthracene was highest for urine than in blood. Urine PAHs showed higher concentration of carcinogenic PAHs than blood. Elimination ratios (ER) such as for acenaphthene (0.06) and anthracene (Ant; 0.11) were considered low while values such as for FLa (1.36) and indeno [1, 2, 3-cd] pyrene (1.55) were considered high ER. Trends in elimination ratios showed close similarity. In conclusion there was elevated PAHs in blood and urine of children with consequent high carcinogenic and then non-carcinogenic risks. This research is significant in setting the stage for more detailed work at same time alerting policy makers on the need for urgent mitigation steps that will reduce children exposure to this class of dangerous pollutants.