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Effect of Polypropylene Microplastics Concentration on Wastewater Denitrification
Xiongshuang Su,
Cheng Chen,
Jia Li,
Shun Lu,
Guihua Xu
Issue:
Volume 10, Issue 3, June 2022
Pages:
53-60
Received:
20 April 2022
Accepted:
5 May 2022
Published:
12 May 2022
Abstract: Microplastics have been ubiquitously in the environment, and a large number of microplastics have entered wastewater treatment plants, and their effects on activated sludge denitrification are rarely reported. Polypropylene (PP) microplastics were selected as the research object for denitrification research. Herein, we set different concentrations of PP microplastics to study their effect on sewage denitrification. Several indicators including NO3--N, NO2--N, Total-N (TN), extracellular polymer substances, Zeta potential, and N2O production, etc., were employed to evaluate the denitrification effect. Results demonstrated that the denitrification process was affected by the concentration of PP microplastics. Its concentration may damage the denitrification of sludge, especially in low concentrations, due to its slowing down the NO2--N reduction process. Meanwhile, it will release an amount of greenhouse gas N2O as the concentration is positively correlated. However, the removal of NO3--N is almost unaffected in different concentrations of PP microplastics during the denitrification process. When the concentration of PP microplastics reached 60 mg L-1, the accumulation of NO2--N in the effluent increased significantly. Accordingly, the extracellular polymer and potential indicators also showed that PP microplastics will reduce the flocculation capacity of the sludge, resulting in a decrease in the denitrification efficiency of the sludge overall. When the concentration of PP microplastics exceeded 100 mg L-1, the impact of microplastics on denitrification water quality indicators was relatively small, but it will increase the N2O emission with a negative impact. In addition, the activated sludge denitrification pathway can be affected by the addition of different microplastics and requires further investigations in the future.
Abstract: Microplastics have been ubiquitously in the environment, and a large number of microplastics have entered wastewater treatment plants, and their effects on activated sludge denitrification are rarely reported. Polypropylene (PP) microplastics were selected as the research object for denitrification research. Herein, we set different concentrations ...
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Pollution and Ecological Risk Assessment of Traces Metals in the Sediments of Gold Mining in Savanna District (Korhogo and Tengrela), Côte d'Ivoire
Koffi Pierre Dit Adama N’goran,
N’guessan Louis Berenger Kouassi,
Donourou Diabate,
Ahbeauriet Ahmed Ouattara,
Kakou Charles Kinimo,
Koffi Marcellin Yao,
Albert Trokourey
Issue:
Volume 10, Issue 3, June 2022
Pages:
61-72
Received:
2 April 2022
Accepted:
7 May 2022
Published:
19 May 2022
Abstract: Metallic contamination of the environment by mining activities constitute a major problem, regarding the exposure risks of the populations and wildlife. Unfortunately, few data are available on metallic contamination of water resources in West Africa. The present study aims to understand the distribution, mobility and potential toxicity of some trace metals (Co, Cr and Zn) in mining sediments and their impact on human health. Sediment samples were analysed for total metal concentration by acid digestion and then by chemical fractionation of trace metals using the modified BCR sequential extraction method. The pollution index results for Cr, Co, and Zn, in the study area sediments, indicated the spread of heavy metal pollution. The sequential extraction demonstrated that most of the trace metals such as Cr (71.02-84.32%), Co (62.00-72.83%) and Zn (66.61-72.01%) were present in a residual form. Overall, Co, Cr and Zn exhibited low individual contamination in the studied sediments. Indeed, their IFC values were less than 1. The GCF results (GCF <6) showed an overall low risk potential related to the complex influence of metals on the environment. Generally, the MRI values for trace metals (Co, Cr and Zn) are below 150, indicating a low environmental risk in all the studied mining areas.
Abstract: Metallic contamination of the environment by mining activities constitute a major problem, regarding the exposure risks of the populations and wildlife. Unfortunately, few data are available on metallic contamination of water resources in West Africa. The present study aims to understand the distribution, mobility and potential toxicity of some tra...
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Studying the Effect of Silica on Some Physico-Mechanical Properties and Morphological Behavior of Bagasse Filled Styrene Butadiene Rubber
Eyad Sayed Abdallah Khalaf
Issue:
Volume 10, Issue 3, June 2022
Pages:
73-80
Received:
16 April 2022
Accepted:
28 April 2022
Published:
19 May 2022
Abstract: Currently, the incorporation of ground cellulosic bagasse as a supplement reinforcing filler in rubber composites is considered to be one of the favorite means that could potentially assist in avoiding the utmost problematic environmental pollution due to the ashes left after burning of agricultural wastes. In addition, it may act in reducing the cost simultaneously with preserving the rubber vulcanizates physico-mechanical properties. In this study, a systematic work was implemented by preparing a series of mixes based on fixed concentration of 25 phr from natural ground bagasse powder (GBP) on a two roll mill to investigate the effect of different quantities (0 – 80 phr) of fumed silica (Si) on the cure characteristics, physical and mechanical properties of Bagasse-Styrene Butadiene Rubber (B-SBR) composites. A grinding machine was used, to obtain GBP with a selective grain size distribution ranging from about 20-180 µm. As well, the interfacial adhesion between SBR and bagasse was improved by adding 2.5 phr of maleic anhydride (MA), as a compatibilizer. It was obvious that values for both tensile strength and modulus at 100% elongation have recorded a significant increase with the increase in Si addition till reaching an optimum concentration of 60 phr, and then a gradual decrease in values takes place with further Si addition. Similarly, hardness recorded a gradual increase in values with the increase in Si content. On the other side the abrasion loss and degree of swelling values are enhanced by showing a marked decrease in values with the increase in silica content. It was evident that modified SBR brings well physico-mechanical properties and wear resistance. Thereby, it’s worth derived that the overall performance of Si filled SBR composites is well preserved in the presence of bagasse powder. The prepared modified SBR composite samples were also characterized by scanning electron microscope (SEM), which reveals a behavior confirming the improved mechanical properties.
Abstract: Currently, the incorporation of ground cellulosic bagasse as a supplement reinforcing filler in rubber composites is considered to be one of the favorite means that could potentially assist in avoiding the utmost problematic environmental pollution due to the ashes left after burning of agricultural wastes. In addition, it may act in reducing the c...
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Health Risk Assessment of Organochlorine Compounds at a Crude Oil-Impacted Soil in at Okpare-Olomu and Ihwrekreka Communities the Niger Delta
Ogunkeyede Akinyemi Olufemi,
Isukuru Efe Jeffery,
Adebayo Adedoyin Ayorinde,
Adedosu Taofik Adewale,
Tawari-Fufeyin Prekeyi
Issue:
Volume 10, Issue 3, June 2022
Pages:
81-92
Received:
4 May 2022
Accepted:
19 May 2022
Published:
8 June 2022
Abstract: Organochlorine compounds (OCCs) are part of molecules that form the complex nature of crude oil. They bioaccumulate in animals and humans to concentrations with the potential to cause non-cancer and cancer-related diseases. OCCs undergo biodegradation to form more toxic complexes in the environmental media. Hence, it is essential to determine the concentration levels of OCCs in crude oil-polluted sites and the health risk they pose within the environmental media in the Okpare-Olomu and Ihwrekreka communities of Delta State, Nigeria. Environmental samples (water, soil, and sediments) were collected from oil spill sites at Okpare-Olomu and Ihwrekreka communities prepared with USEPA Method 8081b in the laboratory for gas chromatography-mass spectrometric (GC-MS) analysis to determine the concentration levels of OCCs. The GC-MS analysis results revealed common OCCs such as Heptachlor epoxide, Endosulfan II, Methoxychlor, Alpha-Lindane, gamma-Lindane and p, p'-DDD. The OCCs observed have two sources, directly from the crude oil spill and the biodegrading effect of the environmental agents. A good correlation was recorded among the OCCs at Ihwrekreka, and Okpare-Olomu according to Pearson's correlation with a moderately positive correlation (r = 0.514, p < 0.991), a good correlation recorded among the OCCs, which means that any observed health-related challenges within each community are likely to be from similar source; i.e. crude oil spills. The OCCs with high concentrations ranging from 2–140 mg/l were observed for Heptachlor epoxide II, Endosulfan II, Methoxychlor and p, p–DDD. The presence and concentrations of the OCCs from Ihwrekreka and Okpare-Olomu indicate the potential of OCCs to cause health-related problems. Hence, non-cancer and cancer risk assessments of OCCs in samples were performed on water samples because the river serves as a source of drinking water for the two communities. The non-cancer risk results in both communities revealed that Endosulfan II has the potential to affect all age groups, while Methoxychlor and Heptachlor epoxide (Isomer A) could only affect teenagers. The risk potential of cancer was very high for most of the OCCs (CR > 10-6), and compounds such as Heptachlor epoxide (Isomer A), Endosulfan II, p, p'-DDD, and Endosulfan sulfate were already at a state that required protective measures (CR = 10-3). Consequently, the study revealed that the water within the two communities could potentially cause both non-cancer and cancer risks to the communities.
Abstract: Organochlorine compounds (OCCs) are part of molecules that form the complex nature of crude oil. They bioaccumulate in animals and humans to concentrations with the potential to cause non-cancer and cancer-related diseases. OCCs undergo biodegradation to form more toxic complexes in the environmental media. Hence, it is essential to determine the c...
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