Level of Trace Metals and Associated Impact on Biochemical, Hematological, and Genotoxic Effects in Occupationally Exposed Waste-Collecting Workers Volume 58- Issue 2

Umra Rasool^1* and Peter Thomson²

• ¹Department of Zoology, Faculty of Science and Technology, GC Women University, Pakistan
• ²Department of Agriculture, Division of Sydney school of Veterinary Science, The university of sydney, Australia

Received: August 01, 2024; Published: August 20, 2024

*Corresponding author: Umra Rasool, Department of Zoology, Faculty of Science and Technology, GC Women University, Faisalabad-38000, Pakistan

DOI: 10.26717/BJSTR.2024.58.009132

Abstract PDF

ABSTRACT

The poor disposal of solid wastes can influence the health of the occupationally exposed workers, collecting the solid wastes. The present study aimed at determining the level of the trace metals (Ni, Cr, Cd, Pb) in the blood of these occupationally exposed workers to solid wastes. Furthermore, the study explored the related genotoxic, biochemical, and hematological effects of the trace metals on solid waste collection workers. The blood samples were collected from a total of 100 solid waste collection workers (experimental group) and their BMI was recorded (20.1±2 kg/m²) whereas a total of 50 local individuals were recruited as control group and their BMI was recorded (19.40±1.7 kg/m²). The concentration of metals (Ni, Cr, Cd, Pb) was observed to be significantly higher (P ≤ 0.05) in the blood of experimental group as compared to control. The metals accumulation in the blood was in the order of Pb>Cr>Ni>Cd. The results of the hematological assessment showed a significant reduction (P ≤ 0.05) in Red blood cells (RBCs), Hemoglobin (Hb), Hematocrit (HCT), Mean Corpuscular Hemoglobin (MCH), Mean Corpuscular Volume (MCV), and Mean Corpuscular Hemoglobin Concentration (MCHC). The Plateletes (Pt) and Mean Plateletes Volume (MPV) were found to be significantly elevated (P ≤ 0.05) in the exposed individuals. In workers, the liver enzymatic activities was observed to be higher (P ≤ 0.05) in terms of AST, ALT, D.Bili, T.Bili with a significant (P ≤ 0.05) reduction in the level of ALP. Similarlty, the level of Creatinine and Urea were significantly elevated (P ≤ 0.05) in the experimental group. However, no significant difference was observed in the micronuclei induction (genetic damage parameters) in both the groups. The exposed individuals are at risk of occupational disease development due to lack of protective devices and poor environmental conditions.

Keywords: Heavy Metals; Solid Wastes; Occupationally Exposed Workers; Bioaccumulation; Hematology; Biochemical Profiling

Abbreviations: RBC: Red Blood Cells; HB: Hemoglobin; HCT: Hematocrit; MPV: Mean Plateletes Volume, PT: Plateletes; MN: Micronelus; MCH: Mean Corpuscular Hemoglobin; HCT: Hematocrit; WBC: White Blood Cell Count; PCV: Packed Cell Volume; MCV: Mean Corpuscular Volume; AP: Alkaline Phosphatase; ALT: Alanine Aminotransferase

Introduction

The developing countries are faced with the grave challenge of solid waste management (Cruvinel, et al. [1]). Approximately 2.01 billion tons of solid waste was generated in 2016 (Kaza, et al. [2]), which is projected to increase by 70% (3.40 billion tons) by 2025 (Laso, et al. [3]). Keeping in view the current scenario of Pakistan, a huge gap lies between solid wastes generation and their proper disposal at the dedicated dumping site. For example, a study conducted by the ministry of environment of Pakistan revealed the generation of waste at the rate of 0.391 kg/capita/day, 2.73 kg/house/day, a total of 924.3 tons of waste per day, and approximately 337, 370 tons/year in Faisalabad city (EPMC, et al. [4]). Keeping in view the instantaneous growth in the population of the city, the production of solid waste is expected to double in next few years. Due to inadequate management of solid waste, various hostile impacts on health and social life of the waste collecting workers have been noticed. The solid waste places are at risk of poor quality of life in urban areas. These workers are at risk in developing areas (de Araujo, et al. [5]). Approximately 2 million individuals operate informally as waste pickers globally. These individuals are the first to suffer as a result of insufficient and poor solid waste management (Ma, Hipel, et al. [6]). The intensity and types of risk imposed depend on their working circumstances including recycling centers, warehouses, on the roads, or in garbage dumps (Gutberlet, et al. [7]). Lack of access to personal protection equipment and hygiene practices increases the individual risk factors (Abarca-Guerrero, et al. [8]).

These risk factors are associated with extreme social vulnerability and harsh conditions, with a variety of intoxicating substances such as trace metals in over permissible limits affecting their central nervous system, for instance, which further expands their vulnerabilities health-wise (Ncube, et al. [9]). During occupational exposure, the workers are subjected to different chemicals and organic agents as well as physical elements in addition to hostile situations related to their jobs. Waste collecting workers are exposed to multiple health dangers besides protection threats (Aliyu Shehu, et al. [10,11]). A variety of waste elements are generated, disposed off, and handled by waste collection workers. These waste-collecting workers are constantly exposed to these solid waste contaminants. Long-term continuous exposure to solid waste contaminations including heavy metals may lead to occupational diseases in the exposed workers (Tiwari, et al. [12,13]. Heavy metals are defined as metals with greater or greater than 5g/cm of specific gravity. The most common metals are copper, nickel, chromium, lead, cadmium mercury, and iron. Some heavy metals like nickel and iron, if low in concentration, are crucial for survival or all types of life (Leah Johnny, et al. [14]). However, even in small quantities, heavy metals like lead, mercury, and cadmium are toxic to human beings and trigger anomalies in the organism's metabolic processes, particularly in larger amounts (Manahan, et al. [15]). Exposure to these toxic metals is prevalent in the sector, where metals are used in a broad variety of methods of production.

The existence of heavy metals such as Cd and Pb, respectively, replaces Ca and Zn with competition in biological systems with binding locations (Smith-Sivertsen, et al. [16]). In a nutshell, all heavy metals in high concentrations are toxic (Zukowska Biziuk, et al. [17,18]). Human biomonitoring for toxic metals continues to receive significant attention as efforts to avoid health risks are on a continuous increase. The main objective of biomonitoring research is to assess human exposure by comparing toxic element levels measured and compared with control group levels or background values based on literature. Due to their existence in surroundings and the resemblance of certain variables associated in biochemical pathways with biochemical interaction, lead, arsenic, cadmium, and mercury, depict the features of these metals and are of specific concern. Heavy metals induce toxicity by making complexes with cellular compounds containing sulfur, oxygen, or nitrogen (Aguilera, et al. [19-21]) upon entering into the living body via drinking water, food, and air. These complexes deactivate or regulate protein or enzyme systems that cause cellular dysfunction and ultimately necrosis (Sharma, et al. [22]). The exposure to heavy metals also lead to DNA damage, which is assessed through different assays including micronelus (MN) assay. MN assay is widely adopted to assess genotixicty induced after exposure to toxic chemicals (Morita et al. 2011) (Claxton, et al. [23,24]). MN assay is considered to be a trademark of viable genotoxicity among waste-collecting workers (Albertini et al. [25,26]). The current study was aimed to investigate the blood bioaccumulation of heavy metals (Pb, Ni, Cd, Cr) and the toxic impacts of exposure to solid waste on the collection wokers in terms of their hematology, serum biochemistry, and genotixicity in Faisalabad district (Pakistan). The resulting framework aid in understanding adverse health outcomes due to poor solid waste collection practices.

Materials and Methods

Sampling sites and criteria

Study Area and Experimental Design

A total of 100 solid waste collecting workers were randomly recruited from different places of Faisalabad district volunteerly whereas 50 individuals were sampled as control group from the same study area.

Sample Selection

Criteria for the selection of blood samples involve workers in different working places of the city. The age was between 25-60yrs. All blood samples were collected from industrial or non-industrial places followed by the aseptic condition. The amount of blood sample was 5ml from the forearm kept in the median cubital vein. Samples were divided into two parts first kept into the anti-coagulated Vacutainer and the other 3ml collected in serum Vacutainer. 100 blood samples were collected from different places of Faisalabad mostly exposed and non-exposed from heavy metals from January-May 2019. Blood samples were collected by a professional phlebotomist with a sterilized disposable syringe (SHIFA disposable syringes) (Fonti, et al. [27]).

Ethical Consideration

For conducting the study, ethical approval/consent was procured from the research ethic review committee of the Government College Women University, Faisalabad. The recruited subjects were informed regarding the nature, aim, and objectives of the study verbally. Furthermore, we had their verbal consent about/for publishing this study.

Hematological Assessment

Venous blood (5 ml) was taken from the peripheral veins of each subject's arms and drained in BD Vacutainer EDTA. The hematological parameters such as red blood cell count (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin (MCHC), Packed cell volume (PCV), hemoglobin concentration (Hb), hematocrit (HCT), white blood cell count (WBC) and platelets counts were determined. The hematological assessment was done with a hematological analyzer (Sysmex 17 parameters XK-21 Hematological Analyzer) by following Roohi and Riaz (2006).

Serum Biochemical Analysis of Waste Collecting Workers

Serum Isolation: The whole blood sample collected in a 1.5 mL serum collection tube making sure to avoid hemolysis. The incubated the blood sample at 37 °C for 10 minutes, the centrifugation of the sample at 10,000 rpm for 10 minutes was then made. Removed serum layer transferred for kidney function analysis to a clean tube avoiding the “buffy coat” layer. The serum samples were stored at 4 °C before further analysis.

Biochemical Analysis: The serum is used for the estimation of biochemical constituents. All the serum samples analyzed for clinical chemistry. An automated clinical chemistry analyzer was used to estimate the serum enzyme activity of ALT, AST enzymes, and also for urea and creatinine. The system was initially standardized for worker’s serum. To study the effects of solid waste collecting workers, Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT), Alkaline phosphatase (AP), Bilirubin, D.Bilirubin for liver function tests, and Creatinine and Urea test for kidney function was studied by using an automated analyzer (Boehringer-Mannheim, US) with reagents from the HUMAN Kits (Human Biological Diagnostic, Germany) methodology related to (Ataro, et al.).

I. Micronucleus Assay

• To study genotoxic effects, micronucleus tests were carried out on the blood sample of waste collectors and the control fellows (Garriott, et al. [28]).

• Scoring of Peripheral blood samples (100 ml/sample) were collected in vacutainers and stored at 40 C during transportation to the laboratory (about 6 hours).

• For each individual, after smear preserve from peripheral blood lymphocyte, binucleated cells were studied. To record the number of MN their criteria proposed by IAEA and by (Fenech, et al. [29]).

• Samples were processed on the same day. The assay was carried out by the method of (Fenech, 2007).

Metals Analysis in Blood

For heavy metal analysis, by wet digestion method (2:1 HNO3: HClO4), 3 ml of blood and related concentration detected with Atomic Absorption Spectrophotometer (AA 7000 F with Autosampler and Hydride Vapor Generator, Shimadzu, Japan) were analyzed by following (Riaz, et al. [30]).

Statistical Analysis

The data were analyzed using GraphPad (Version 6). The data analyzed using ANOVA, followed by post-Dunnett's test. The significance of parameters in controls and workers and post-turkey test for comparison for heavy metals Concentration (µg/g) in blood samples was employed.

Results

Health risks associated with occupational solid waste collecting workers were investigated. Body mass of occupational solid waste collecting workers was measured to study the effects of waste material on serum biochemistry parameter, hematology (Figure 1), and genotoxic effects on workers’ health assessed by micronucleus assay (Figures 1 & 2 and Tables 1-3). The concentration of estimated toxic substances (Pb, Ni, Cd, Cr) in the blood of waste collecting workers was also carried out. Concentration analysis of toxic heavy metals (Pb, Cd, Ni, Cr) in the blood serum of workers and control was measured (Data presented in Figure 2). The average Pb level measured in the blood serum of workers is (6.800±2.300) higher than the average Pb concentration of control (4.450±1.100). Similarly, the average Cd level among worker’s blood was observed (2.100±0.5000) higher than the average Cd concentration of control (1.400±0.3000). The average Ni level in workers (16.00±6.300) was higher than the average Ni concentration of control (8.100±2.000) found in the blood of controls. Similarly, the average Cr level in workers (18.00±7.600) was higher than the average Cd concentration of control (7.300±2.200). Long-term exposure to solid waste may imply that the working conditions, nature of the job, and the stress of the job may impact workers' health. There were slight variations in Red Blood Cells in blood samples observed among waste collection workers compared with control. The average red blood cells measured in workers were (4.953±0.2066) which were lower than the average Red blood cells (5.383±0.2095) observed in the blood of control (Data presented in Figure 3.

Note: In workers, males were taken for study, their education level, way of living, habits, and income under consideration.

Note: Comparison of metals concentration in blood of control and waste picker workers. (a) Lead(Pb), (b) Cadmium(Cd), (c) Nickel (Ni), Chromium (Cr). Values are represented as Mean ± SD.ns P > 0.05, *P ≤ 0.05, **P ≤ 0.01, ***P ≤0.001.

This implies that the working conditions, nature of the job, and the stress of the job may impact the frequency of RBCs in workers. There were slight variations in Hemoglobin Concentration (g/dl) in blood samples observed in waste collecting workers compared with control. The average Hemoglobin Concentration (g/dl) measured in workers was (12.85±1.168) which was lower than the Hemoglobin Concentration (g/dl) (15.25±0.8226) observed in the blood of control (Data presented in Figure 3 and Table 3). There were slight variations in Hematocrit Concentration (g/dl) in blood samples observed in waste collecting workers compared with control. The average Hematocrit Test (HCT) level measured in the blood of workers were (41.78±2.935) which was lower than the average HCT of control (46.40±1.608) found in the blood of control (Data presented in Figure 3. Slight variations observed in MCH Concentration (g/dl) in blood samples observed in waste collecting workers compared with control. The average MCH level measured inthe blood of workers was (26.88±4.117) which is lower than the average MCH of control (33.50±2.646) found in the blood of control (Data presented in Figures 3-7. To study the genotoxic effects of heavy metals (Ni, Pb, Cr, Cd), a micronucleus assay was performed. In the present study, the micronucleus assay for white blood cells exhibited a non significant number of micronucleus cells in solid waste collecting workers compared to control. The results of the MN assay revealed no MN in peripheral blood lymphocytes of workers compared with control (Data presented in Figures 8 -10). Waste collection workers showed no genotoxic effects on workers compared with controls.

Discussion

(Steven Jerie, et al. [31]) identified the occupational risks associated with municipal solid waste control practices, health concerns raised about the capacity of harm from waste to the environment and the general public. The lack of health facilities among workers collecting solid waste leads to different diseases in Brazil (Silva, et al. [32]). It is also clear from the results that heavy metals also have a dramatic effect on the hematology of workers. These findings are in line with the study of those who described that alterations in blood parameters constitute one of the effects, which come up from metals exposure. In this study, RBC, hemoglobin concentration, and HCT of waste collecting workers exposed for 0.5-3years, 4-10 years, and above 10 years were significantly decreased (p≤0.05). However, the platelet count was increased compared to control (not exposed to heavy metals in wastes). (Ezeh, et al. [33]) studied hematological parameters among municipal solid waste workers compared with healthy volunteer subjects and observed that contained compounds exposed at the workplace affect the altered hematological parameters. In the present study, a statistically significant decline in the red cell count, hemoglobin, mean corpuscular hemoglobin concentration, the hematocrit value, monocyte, eosinophil, and a non-significant decrease in platelet count in solid waste collection workers observed when compared with the control group. Besides, there was a statistically significant decrease in the total white blood cell compared to the control group may be attributed to depression of the bone marrow.

There was also an increase in lymphocytes, basophil, MPV compared to controls. Our study is correlated with the study of (Wang, et al. [34]) who give a vast concept about the impact of metal toxicity on RBCs. WBCs, Platelets, MCH, MCHC, MPV, basophils, eosinophils etc. An increase in WBC observed in this present study under unhealthy situations, the level of WBC is altered; their concentration in the blood reduces especially in leukemia and acute infections (John and Hole, et al. [35]) Thus based on the present work, the increase in WBC could be from infections and inflammatory disorders since one major task of WBCs is to deliver prime resistance against possible contaminants. In the present work, a decrease in WBC eosinophils and monocytes, RBCs, in whole blood samples were found among workers occupationally exposed to heavy metals for a long period during waste collection practice. An increase in DNA damages can also be correlated with the increase in the duration of exposure to heavy metals especially among workers exposed to heavy metal hazards for more than 20 years of duration of work (Figure 1, Table 1). Metal toxicity has also an impact on the biochemistry of workers. In the present study, the effects of workplace environments focused among garbage collecting workers to estimate effects on the level of ALT, AST, ALP, AP, Creatinine, and urea. Almost all the biochemical parameters viz. alkaline phosphate, alanine aminotransferases, aspartate aminotransferases of liver were raised in the male and female workers. The total bilirubin, direct bilirubin were also higher in the workers as compared with those of non-workers.

Liver function parameters like Urea and Creatinine also increased in exposed workers than non-exposed workers of waste collecting workers. These findings are in confirmation with previous studies (Dongre, et al. [36-38]) as they also reported increase in transaminases among workers exposed to different chemicals. Effects of environmental and industrial pollution on genotoxicity have always been an important issue (Ibruljetal.,2006). (Lidiya et al. [39]) explained the Micronuclei (MN) an extra-nuclear body containing damaged and/or whole chromosome fragments that were not incorporated into the nucleus after cell division. Defects in the cell repair machinery can induce MN and accumulation of DNA damages. A variety of genotoxins reported may induce MN formation leading to cancer development, cell death, or genomic instability. The knowledge accumulated in literature on genotoxins effects precisely reflected and individual sensitivity to MN formation is discussed (Luzhna, et al. [40]). The importance of rapid MN scoring concerning genotoxic effects was also evaluated. It is also clear from the results that, heavy metals also have a not dramatic effect on micronucleus in white blood cells that cause different diseases in waste collecting workers. Over the past century, different studies by cytogeneticists have been describing the genotoxic effect of multiple exposures to heavy metals on cells and organisms (Kirsch, et al. [41]). The potential of ionizing radiation in causing damage to DNA is an example of such genotoxic influence. Different genotoxic agents use a variety of different mechanisms to alter DNA structure and affecting nuclear integrity.

For instance, mitotic spindle disrupting agents cause chromosome missegregation also reported (Elhajouji, et al. [42]), while metals have a variety of cellular targets. Therefore, genotoxic effects have been reported in many heavy metals toxicity studies (Terradas et al. [43]). Personal hygiene and behavioral risk factors were also found associated with high blood metal levels. Personal hygiene is also highly recommended for subject workers [44-126].

Conclusion and Recommendationsions

Heavy metal concentration analysis in waste collecting workers has been widely discussed. This study showed that the levels of chromium and lead were high in the blood of workers as compared to nickel and chromium which were moderate in their blood. Due to the high concentration of metals in blood, the effect on hematological parameters was also evident. A significant change in the White blood cells, Red blood cells, MCV, PCV, and platelet concentration were observed in the exposed individuals as compared to the control group. Similarly a significant impact of metals on liver or kidney functions of waste collecting workers was observed.

Micronucleus assay revealed minor nucleus changes. The current research demonstrated that solid waste workers are at risk of diverse health hazards ranging from infections, inflammatory diseases, leukemia, and allergic disorders. Therefore, adequate protective measures should be adopted, adequate training should be given to these workers, and they should be aware of adhering to the use of protective devices and adequate personal hygiene.

Conflict of Interest

The authors have no conflict of interest to declare.

References

1. Lotto M, PE Aguirre, AP Strieder, AF Cruvinel, T Cruvinel, et al. (2019) Can the levels of toothache-related interests of Google and YouTube users differ between developed and developing countries over the years? PeerJ Preprints 7: e27570v1.
2. Kaza S, Yao L, P Bhada Tata, F Van Woerden (2018) What a waste 2.0: A global snapshot of solid waste management to 2050. World Bank Publications.
3. Laso JG I Herrero, M Margallo, A Bala, P Fullana i Palmer, et al. (2019) LCA-Based Comparison of Two Organic Fraction Municipal Solid Waste Collection Systems in Historical Centres in Spain. Energies 12(7): 1407.
4. (1996) EPMC. National study on privatization on solid waste management in eight cities of Pakistan.
5. De Araujo BC, S Schmidt, O Schmidt, RT Von Rintelen, Ubaidullah, et al. (2018) The Mt Halimun-Salak Malaise Trap project - releasing the most species rich DNA Barcode library for Indonesia. Biodiversity Data Journal 6: e29927.
6. Ma J, KW Hipel, ML Hanson (2017) Public participation in municipal solid waste source-separated collection in Guilin, China: status and influencing factors. Journal of environmental planning and management 60(12): 2174-2191.
7. Gutberlet Jutta (2013) Briefing: Social facets of solid waste: Insights from the global south. Proceedings of the ICE - Waste and Resource Management. 166: 110-113.
8. Guerrero LA, G Maas, W Hogland (2015) Solid waste management challenges for cities in developing countries. Revista Tecnología en Marcha 28(2): 141-168.
9. Ncube Bhekumthetho, Finnie Jeffrey, J Van Staden (2019) Seasonal variation in antimicrobial and phytochemical properties of frequently used medicinal bulbous plants from South Africa. South African Journal of Botany 77(2): 387-396.
10. Aliyu A, A Shehu (2006) Occupational hazards and safety measures among stone quarry workers in Northern Nigeria. Nigerian Med Pract 50(2): 42-47.
11. Wassim E, S Eassa, S Lotfi, S Masry, H Shatat, et al. (2014) Adverse health problem among municipality workers in Alexandria (Egypt). Int J of Preventive Med 5(5): 545-556.
12. Tiwari R (2008) Occupational health hazards in sewage and sanitary workers. Indian J Occup Environ Med 12(3): 112-115.
13. Vehlow J (2015) Air pollution control systems in WTE units: an overview. Int J Environ Waste Manag 37: 58-74.
14. Leah A S C, Johnny A C (2014) Heavy International Journal of Environmental Science and Development (5): 1.
15. Manahan SE (2001) Fundamentals of Environmental Chemistry (2^nd)., CRC Press, LLC Boca Ralton, Florida, pp. 853-861.
16. Tone Smith-Sivertsen, Esperanza Díaz, Dan Pope, Rolv T Lie, Anaite Díaz, et al. (2009) Effect of Reducing Indoor Air Pollution on Women's Respiratory Symptoms and Lung Function: The RESPIRE Randomized Trial, Guatemala. American journal of epidemiology 170(2): 211-220.
17. Zukowska J, M Biziuk (2008) Methodological evaluation of method for dietary heavy metal intake. J Food Sci 73: R21-R29.
18. Taghipour H, Z Amjad, MA Jafarabadi, A Gholampour, P Norouz (2014) Determining heavy metals in spent compact fluorescent lamps (CFLs) and their waste management challenges: some strategies for improving current conditions. Waste Manag 34: 1251-1256.
19. Aguilera G, AL Colín-Gonzalez, E Rangel-Lopez, A Chavarria, A Santamaria, et al. (2017) Redox signaling, neuroinflammation, and neurodegeneration. Antioxid. Redox Signal 28: 18.
20. Kumar A, B Yegla, TC Foster (2017) Redox signaling in neurotransmission and cognition during aging. Antioxid. Redox Signal 28: 18.
21. Trost BM, JS Tracy (2017) Carbon-Nitrogen bond formation via the vanadium oxo catalyzed sigma tropic functionalization of allenols. Org Lett 19: 2630-2633.
22. Soni K, RK Sharma A Gupta, et al. Impact of petroleum fumes on liver and kidney functioning of petrol filling attendants and garage attendants working in South Haryana, India. Eur J Pharm Med Res 3(8): 569-573.
23. Claxton L D (2015) The history, genotoxicity, and carcinogenicity of carbon-based fuels and their emissions: Summary, comparisons, and conclusions. Mutat Res 76(3): 103-147.
24. Hayashi M (2016) The micronucleus test-most widely used in vivo genotoxicity test. Genes and Envir 38(1): 18.
25. Albertini R J, D Anderson, G R Douglas, L Hagmar, K Hemminki, et al. (2000) IPCS guidelines for the monitoring of genotoxic effects of carcinogens in humans. Int Programme on Chemical Safety 463(2): 111-172.
26. Li Y, M Li, Y Liu, G Song, N Liu, et al. (2012) A microarray for microRNA profiling in spermatozoa from adult men living in an environmentally polluted site. Bull Environ Contam Toxicol 89: 1111-1114.
27. Fonti V, F Beolchini, L Rocchetti, A Dell’Anno (2015) Bioremediation of contaminated marine sediments can enhance metal mobility due to changes of bacterial diversity. Water res 68: 637-650.
28. Garriott M L, J B Phelps, W P Hoffman (2002) A protocol for the in vitro micronucleus test: I. Contributions to the development of a protocol suitable for regulatory submissions from an examination of 16 chemicals with different mechanisms of action and different levels of activity. Mutation Research/Genetic Toxicology and Environmental Mutagenesis 517(1-2): 123-134.
29. Fenech M (2007) Cytokinesis-block micronucleus cytome assay. Nature protocols 2(5): 1084-1104.
30. Riaz N J, J Havel, V Makarov, A Desrichard, W J Urba, et al. (2017) Tumor and microenvironment evolution during immunotherapy with nivolumab. Cell 171(4): 934-949.
31. Steven J (2016) Occupational risks associated with solid waste management in the informal sector of Gweru. Zimbabwe J. of Environ. and Public Health 1: 1-14.
32. Silva ACN, RS Bernardes, LRS Moraes, JDP Reis (2002) Criterios adotados para selecao de indicadores de contaminacao ambiental relacionados aos resíduos sólidos de servicos de saúde: uma proposta de avaliacao. Cad Saude Publica 18(5): 1401-1409.
33. Ezeh N P, O M Adienbo K U Nwoke (2017) Some Occupations and Their Effects on Hematological Parameters of Exposed Individuals in Port Harcourt, Nigeria. Human Journals 8(2): 50-57.
34. Wang L, X He, Y Bi, Q Ma (2012) Stem cell and benzene-induced malignancy and hematotoxicity. Chem Res Toxicol 25(7):1303-1315.
35. John W, J Hole (1992) Essentials of human anatomy and physiology (4^th)., USA: Wm. C. Brown Publisher.
36. Dongre NN, A Suryakar, AJ Patil (2010) Occupational lead exposure in automobile workers in north Karnataka (India): effect on liver and kidney functions. Al Ameen J Med Sci 3(4): 284-292.
37. Khan AA, S Inam, M Idrees (2010) Effect of automobile workshop on the health status of automechanics in NWFP, Pakistan. Afr J Environ Sci Technol 4(4): 192-200.
38. A Gupta, et al. Impact of petroleum fumes on liver and kidney functioning of petrol filling attendants and garage attendants working in South Haryana, India. Eur J Pharm Med Res 3(8): 569-573.
39. Lidiya L, P Kathiria, O Kovalchuk (2013) Micronuclei in genotoxicity assessment: from genetics to epigenetics and beyond. Frontiers in genetics.
40. Luzhna L, P Kathiria, O Kovalchuk (2013) Micronuclei in genotoxicity assessment: from genetics to epigenetics and beyond. Front Genet 4: 131.
41. Kirsch Volders, MA Vanhauwaert, U Eichenlaub-Ritter, I Decordier (2003) Indirect mechanisms of genotoxicity. Toxicol Lett 140(141): 63-74.
42. Elhajouji A, PV Hummelen, M Kirsch-Volders (1995) Indications for a threshold of chemicallyinduced aneuploidy in vitro in human lymphocytes. Environ Mol Mutagen 26(4): 292-304.
43. Terradas M, M Martin, L Tusell, A Genesca (2010) Genetic activities in micronuclei: is the DNA entrapped in micronuclei lost for the cell? Mutat Res 705(1): 60-67.
44. Osaretin GI, JI Anetor, O Osibanjo, MA Okungbowa, FA Idomeh, et al. (2018) Variation in some haematological parameters, iron and lead levels in workers exposed to electronic waste in Benin city, Nigeria.
45. Paul BT, CG Yedjou, AK Patlolla, DJ Sutton (2014) Heavy metals toxicity and the environment. National institute of health Public Access Author Manuscript 101: 133-164.
46. Brilliance OA, A N Ezejiofor, ZN Igweze, OE Orisakwe (2018) Heavy Metal Mixture Exposure and Effects in Developing Nations: An Update. Toxics 6(4): 65.
47. Arif TJ, M Azam, K Siddiqui, A Ali, I Choi, et al. (2015) Heavy metals and human health: Mechanistic insight into toxicity and counter defense system of antioxidants. Int J Mol Sci 16(12): 29592-29630.
48. Srinivas C, M Kumari, KR Devi, US Murty, MF Rahman, et al. (2014) Assessment of genotoxic effects of lead in occupationally exposed workers. Environ Sci Pollut Res 21(19): 11469-11480.
49. Akan JC, OA Sodipo, Y Liman, ZM Chellube (2014) Determination of heavy metals in blood, urine and water samples by inductively coupled plasma atomic emission spectrophotometer and fluoride using ion-selective electrode. J Anal Bioanal Tech 5(6).
50. Nkop EJ, AM Ogunmolasuyi, KO Osezua, NO Wahab (2016) Comparative study of heavy metals in the soil around waste dump sites within University of Uyo. Archives of Applied Science Research 8 (3): 11-15.
51. Ekram W Abd El Wahab, Safaa M Eassa, Sameh E Lotfi, Sanaa A El Masry, Hanan Z Shatat, et al. (2014) Adverse health problems among municipality workers in alexandria (egypt). Int J Prev Med 5(5): 545-556.
52. Abeliotis K, K Karaiskou, A Togia, K Lasaridi (2009) Decision support systems in solid waste management: A case study at the national and local level in greece. GLOBAL NEST J 11(2): 117-126.
53. Addo IB, D Adei, EO Acheampong (2015) Solid Waste Management and Its Health Implications on the Dwellers of Kumasi Metropolis, Ghana. Current Research J Social Sci 7(3): 81-93.
54. Alam Zeba, Carandang (2016) International Journal of cell science. The Impact of E Waste Toxicity -An Emerging Global Challenge Int J Cell Sci the Impact of E waste Toxicity - An Emerging Global Challenge. Int J Cell Sci 1: (1).
55. Wael K Al-Delaimy, Catherine Wood Larsen, Keith Pezzoli (2014) Differences in health symptoms among residents living near illegal dump sites in Los Laureles Canyon, Tijuana, Mexico: a cross sectional survey. Int J Environ Res Public Health 11(9): 9532-9552.
56. Aliyu A, A Shehu (2006) Occupational hazards and safety measures among stone quarry workers in Northern Nigeria. Nigerian Med Pract 50(2): 42-47.
57. Antwi SO, EC Eckert, CV Sabaque, ER Leof, KM Hawthorne, et al. (2015) Exposure to environmental chemicals and heavy metals, and risk of pancreatic cancer. Cancer Causes Control 26(11): 1583-1591.
58. Cointreau S (2006) Occupational and environmental health issues of solid waste management: Special emphasis on middle- and lower-income countries 1: 57.
59. Couth R, C Trois (2012) Sustainable waste management in Africa through CDM projects. Int J Environ Waste Manag 32(11): 2115-2125.
60. Porta D, S Milani, A Lazzarino, AC Perucci, F Forastiere, et al. (2009) Systematic review of epidemiological studies on health effects associated with management of solid waste. Environ Health 8: 60.
61. El Haggar SM (2007) Sustainable industrial design and waste management: Cradle-to-cradle for sustainable development. 8(3): 424.
62. Englehardt JD, LE Fleming, JA Bean (2003) Analytical predictive Bayesian assessment of occupational injury risk: municipal solid waste collectors. Risk anal 23(5): 917-927.
63. Ezeh NP, OM Adienbo, KU Nwoke (2017) Some occupations and their effects on hematological parameters of exposed individuals in port harcourt, Nigeria 8(2): 50-57.
64. Bhada Tata P, Hoornweg A Daniel (2012) What a waste: A global review of solid waste management. In. urban development series 1: 116.
65. Jerie S (2011) Gender and solid waste management in the informal sector of Bulawayo, Zimbabwe. The Dyke 5(1): 46-64.
66. Jovanovic J, M Arandelovic, M Jovanovic (2004) Multidisciplinary aspects of occupational accidents and injuries. Working and Envir Protection 2: 325-333.
67. Lazzari MA, CB Reis (2011) The urban garbage collectors in the municipality of Dourados (MS) and their perception on the biological risks in their work process. Sci. and Collective Health 16(8): 3437-3442.
68. Loboka MK, Q Shihua, JL Celestino, SO Hassan, S Wani, et al. (2013) Municipal solid waste management practices and fecal coliform water contamination in the cities of developing countries. Int J Environ Sci 3(5): 1614-1624.
69. Pfeffer N, S Laws (2006) It’s only a blood test: What people know and think about venipuncture and blood. Soc Sci Med 62: 3011-3023.
70. Priyanka V Patil, RK Kamble (2017) Occupational health hazards in municipal solid waste collecting workers of Chandrapur city, central India. Int J of environ 6: 46 -57.
71. Scharff H (2014) Landfill reduction experience in the Netherlands. Int J Environ Waste Manag 34(11): 2218-2224.
72. Subramani T, S Krishnan, SK Ganesan, G Nagarajan (2014) Investigation of mechanical properties in polyester and phenylester composites reinforced with chicken feather fiber. Int J Eng Res Appl 4(5): 88-99.
73. Tilaye M, M P Van Dijk (2014) Private sector participation in solid waste collection in Addis Ababa (Ethiopia) by involving micro-enterprises. Waste Manag Res 32(1): 79-87.
74. Jayakrishnan T, MJ Jeeja, R Bhaskar (2013) Occupational health problems of municipal solid waste management workers in India. Int J Env Health Eng 2(3): 42.
75. Sharma D, GS Kaur, KS Khera (2015) Triazophos-induced oxidative stress and histomorphological changes in ovary of female Wistar rats. Pestic Biochem Physiol 117: 9-18.
76. John W, J Hole (1992) Essentials of human anatomy and physiology (4^th )., USA: Wm. C. Brown Publisher.
77. Ogunrinola I, Oluranti (2012) Health and Economic Implications of Waste Dumpsites in Cities: The Case of Lagos, Nigeria. International Journal of Economics and Finance 4(4): 239-251.
78. Priyanka V, Patil R K Kamble (2017) Occupational health hazards in municipal solid waste collecting workers of chandrapur city, central india. Int J env 6(1): 46.
79. Thayyil J, M C Jeeja, R Bhaskar (2013) Occupational health problems of municipal solid waste management workers in India. International Journal of Environmental Health Engineering 2(3).
80. Muhammad M A, F R Shakoori, A R Shakoori (2016) Biochemical and Haematological Abnormalities in Factory Workers Exposed to Hexavalent Chromium in Tanneries of Kasur District. Pakistan J Zool 38(3): 239-253.
81. Vivianni PW, F L A Fonseca, A V Quiaios, J N Domingues, S Paixao J Figueiredo, et al. (2017) Socio-Environmental and Hematological Profile of Landfill Residents. Int J Environ Res Public Health 14: 64.
82. Alam ZF, C Jsrvi (2016) The Impact of E waste Toxicity - An Emerging Global Challenge. International Journal of cell science 1(1).
83. Mihaela S, S Oancea, Doina, C Obreja (2009) Comparative study of genotoxic effects in workers exposed to inorganic lead and low dose irradiation using micronucleus test. Rom J Leg Med 4: 287-294.
84. Al Shoeb MA, MH Rahman, S Chakraborty, M Faisal, TMZ Waise, et al. (2014) Cytogenetic Assays of Genotoxic Effects and Cancer Risk of Chromium on Tannery Workers in Bangladesh. Journal of Biology 2(2): 39-46.
85. Srinivas CM, Kumari KR, Devi US, Murty MF Rahman, SI Kumari, et al. (2014) Assessment of genotoxic effects of lead in occupationally exposed workers. Environ Sci Pollut Res 21(19): 11469-11480.
86. Maxim YSI, Varvara Minina, INikolay, GA Maxim, Asanov, et al. (2016) Assessment of DNA damage in underground coal miners using the cytokinesis-block micronucleus assay in peripheral blood lymphocytes. Mutagenesis 31(3): 669-675.
87. Jarup L (2003) Hazards of heavy metal contamination. British medical bulletin 68(1): 167-182.
88. Monisha Jaishankar, Tenzin Tseten, Naresh Anbalagan, Blessy B Mathew, Krishnamurthy N Beeregowda, et al. (2014) Toxicity, mechanism and health effects of some heavy metals. Interdisciplinary toxicology 7(2): 60-72.
89. Lars J (2003) Hazards of heavy metal contamination. British medical bulletin 68(1): 167-182.
90. Viroj W (2008) Minor heavy metal: A review on occupational and environmental intoxication. Indian journal of occupational and environmental medicine 12(3): 116-121.
91. Clausen J, S Rastogi (1977) Heavy metal pollution among autoworkers. I. Lead. Occupational and Environmental Medicine 34(3): 208-215.
92. Bakri M M A, Ariffin, Nurliyana, Abdullah, Z, Rozainy, et al. (2017) Geopolymer as an adsorbent of heavy metal: A review. AIP Conference Proceedings 1885(1).
93. Wasowicz W G, Jolanta, R Konrad (2001) Blood concentration of essential trace elements and heavy metals in workers exposed to lead and cadmium. International journal of occupational medicine and environmental health 14(3): 223-239.
94. Hassan H S, M I Sule, A M Musa, K Y Musa, M S Abubakar, et al. (2006) Anti-inflammatory activity of crude saponin extracts from five Nigerian medicinal plants. African Journal of Traditional, Complementary and Alternative Medicines 9(2): 250-255.
95. Ekram W Abd El-Wahab, Safaa M Eassa, Sameh E Lotfi, Sanaa A El Masry, Hanan Z Shatat, et al. (2014) Adverse health problems among municipality workers in alexandria (egypt). Int J Prev Med 5(5): 545-556.
96. Sullivan J B, G R Krieger (2001) Clinical Environmental Health and Toxic Exposure. Med Sustentab 7(1): 32-39.
97. Brinkel J, MH Khan, A Kraemer (2009) A systematic review of arsenic exposure and its social and mental health effects with special reference to Bangladesh. Int J Environ Res Public Health 6(5): 1609-1619.
98. Krajewski L, J Wei, L L Tang (2005) Responding to schedule changes in build-to-order supply chains. J oper manag 23(5): 452-469.
99. Patil PV, RK Kamble RK (2017) Occupational Health Hazards in Municipal Solid Waste Collecting Workers of Chandrapur City. Central India 6(1).
100. Mahurpawar M (2015) Effects of heavy metals on human health. Int J Res Granthaalayah 3: 1-7.
101. Duda Chodak A, U Blaszczyk (2008) The impact of nickel on human health. Journal of Elementology 13(4): 685-693.
102. Barceloux DG (1999) Nickel. Clin Toxicol 37(2): 239-258.
103. Zamponi GW, E Bourinet, TP Snutch (1996) Nickel block of a family of neuronal calcium channels: Subtype- and subunit-dependent action at multiple sites. J Membr Biol 151(1): 77-90.
104. Rabinowitz M (1991) Toxicokinetics of bone lead. Environ Hlth Perspect 91: 33-37.
105. Silbergeld EK (1988) Lead in bone: implications for toxicology during pregnancy and lactation. Env Health Perspect 91: 63-70.
106. Goyer RA (1993) Lead toxicity: current concerns. Env Health Perspect 100: 177-187.
107. Beck BD (1992) Symposium overview: An update on exposure and effects of lead Fund Appl Toxicol 18(1): 1-16.
108. (1993) ATSDR. Toxicological Profile for Lead. U.S. Department of Health and Human Services. Public Health Service.
109. Ma J, K W Hipel, M L Hanson (2017) Public participation in municipal solid waste source-separated collection in Guilin, China: status and influencing factors. Journal of environmental planning and management. 60(12): 2174-2191.
110. Gutberlet Jutta (2013) Briefing: Social facets of solid waste: Insights from the global south. Proceedings of the ICE - Waste and Resource Management 166: 110-113.
111. Shirin Ziaei, Ruchira Tabassum Naved, Anisur Rahman, Rubhana Raqib, Eva-Charlotte Ekstrom, et al. (2019) Maternal Experience of Domestic Violence, Associations with Children’s Lipid Biomarkers at 10 Years: Findings from MINIM at Study in Rural Bangladesh. Nutrients 11(4): 910.
112. Emmatty F J, V V Panicker (2019) Ergonomic interventions among waste collection workers: A systematic review. International Journal of Industrial Ergonomics 72(3-7): 158-172.
113. Duda-Chodak A, U Blaszczyk (2008) The impact of nickel on human health. Journal of Elementology 13(4): 685-693.
114. Bradberry S M, T C Aw (2001) Occupational methaemoglobinaemia. Occupational and environmental medicine 58(9): 611-611.
115. Adesina O O, A O Omobola, O E Maria, E Martins (2012) The levels of inflammatory markers and oxidative stress in individuals occupationally exposed to municipal solid waste. Toxicol Ind. Health 29(9): 846-855.
116. Chung S L, W L Young, H K Ho, Y Y Ji, C S Dong, et al. (2011) Exposure to heavy metals in blood and risk perception of the population living in the vicinity of municipal waste incinerators. Environmental science and pollution research 19(5): 1629-1639.
117. Wachukwu K, Confidence, E U Eleanya (2007) Health impact assessment of solid disposal workers in Port Harcourt, Nigeria. Journal of applied sciences 7(22): 3562-3566.
118. Yin S N, R B Hays, M S Linet (1996) A cohort study of cancer among benzene-exposed workers in China: overall results. Am J Ind Med 29: 227-235.
119. Yan C, L Guilan, Y Songnian (2002) Individuals susceptibility to hematotoxicity from benzene exposure and the genetic polymorphism of metabolic enzymes 31(2): 130-132.
120. Descatha A, A Jenabian, F Conso, J Ameille (2005) Occupational exposures and hematologicalmalignancies: Overview on human recent data. Cancer Causes Control 16(8): 939-953.
121. Merghad A, A Cheriff (2014) Hematological profile of painters AENSI (American-Eurasian networksfor scientific information) journals 8(24): 37-42.
122. S Bradberry, T Aw, N Williams, J Vale (2001) Occupational methemoglobinemia. Occup Environ Med 58(9): 611-616.
123. Lee C H, S H Kim (2013) Two Cases of Methemoglobinemia Induced by the Exposure to Nitrobenzeneand Aniline. Ann Occup Environ Med (25): 31.
124. Min JW, S Y Park (2013) Case of acute methemoglobinemia caused by nitrobenzene ingestion. Korean JMed 84(3): 442-445.
125. Olufunsho A, D P Temidayo, S O Bawo, A Akin, A B C Herbert, et al. (2014) Occupationalhazards and safety measures amongst the paint factory workers in Lagos. Science Direct.
126. Giusti L (2009) A review of waste management practices and their impact on human health. Waste Manag 29(8): 2227-2239.