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Epistemology and Metaphysics 101
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Epistemology and Metaphysics 101
Introduction
Real human experiences have distinctive characteristics that differentiate them from the consciousness states that are defined by the complex thought processes. Actual experiences do not only accredit human existence, but they also enable humans to interact with the physical world and appreciate the existence of other forms. Usually, humans are triggered to become conversant with different events once they realize that they are in actual existence. Since historical times, the concept of human experience has been under philosophical scrutiny and seemingly, various philosophers have explored inherent dynamics for various reasons. The concept of sense data has particularly been contentious because of the implications that it has on these states.
While some philosophers have argued that the physical world can be perceived, others indicate that this ability is too complex and is beyond human capacity. Yet others maintain that although this is possible, it is compounded by various inconsistencies with respect to the actual appearances of the perceived objects. Besides being characterized by human thought processes and experiences, sense data can not entirely accredit the belief in the physical world. From his point of view, Russell presumed that the belief in the external world can not be based on any direct experience or sense data. This is true and this essay demonstrates that counter arguments are faulty.
The sense data conception constitutes the qualities and characteristics that humans primitively and immediately conceive about the physical objects. These include shape, texture, temperature, color and so forth. The relative theory stipulates that these perceived characteristics assume the functions of physical objects. Thus for instance, the perception that a sheep has soft fur in this regard makes the human mind associate it with attributes of warmth and softness. This is faulty because the human mind would believe that the sheep is the one responsible for the warmth and softness. This happens regardless of one being unsure of the very existence of the sheep.
Russell objects this conception and assumes a logical argument. In this, the existence of the physical objects presumes perception rather than perception occurring prior to actual experience. Fundamentally, this is true because a mere perception can not underscore the existence of a physical object that has the perceived qualities. At this point, sense data can be considered as just a state of the mind and does not have any implications on the real existence of the physical world.
Further, Russell indicates that the aspect of private and public space also disqualifies the sense data from the presumed function. In this respect, Russell argues that unlike the physical world that assumes a public space, the sense data is largely private and hence subjective in nature (Russell 63). This can not be used to define the real attributes of a physical world that is already in existence. In stead, the latter needs to shape the perceptions of the former. Coupled by the realization that the peoples’ mind and what is perceived in them is unknown to the mind of an individual, it becomes difficult for one to align individual thoughts and perception to that of the entire public. In this respect therefore, the possibility of having a uniform perception of the external world is impossible. Since the world itself has distinct features, there are inherent inconsistencies that undermine the credibility of the sense data theory.
Russell’s preposition is consistent with the proposition of the representative realism that believes that sense data can not imply the existence of the external world because of the lack of objectivity and proof. In this regard, humans perceive physical things differently even in actuality. This is usually influenced by various aspects that range from the position of viewing the objects to the level of integrity of the individual. In addition, it postulates that humans do not have the ability to perceive the external world directly; rather this is made possible through the sense data. Whereas naïve realists perceive before they see the external world, representative realists base their perception on the sensory representation of the external world. In essence, perceptions are triggered by the inherent qualities of the external world that then provide the basement for inference.
From his point of view, Descartes argues that sense data can accurately represent the primary qualities of external objects, events and properties. However, he cites that the sense data of perceptual illusions and secondary qualities does not accurately represent the properties, objects or events in the external world. Secondary qualities usually produce sensations and are intrinsic of the observers. Typical examples include sound, smell, color and taste. The relative knowledge stems from such qualities is therefore highly objective and can not be used to provide objective and factual information about events and objects found in the external world.
This is regardless of the fact that it might be greatly influenced by the primary qualities of the external world. To counter the intrinsic shortcomings, Descartes supports the employment of critical realism that adopts the concept of representation. Notably, this is consistent with the provisions of the theory of perception. At this point, it is certain that humans can not accurately describe an item that they are acquainted with. Although this has been objected on the premise that apriori knowledge enables one to do so, it can be argued that such knowledge is based on false objectivity. In this regard, it is possible that such information was provided by someone who had an experience with the object and can therefore be classified as being subjective.
Conclusion
Human experiences often enable one to have an actual understanding of the real and objective world. Real experiences can be differentiated from unconscious experiences because the former is objective. Sense data theory presumes that the perceive attributes are an actual representation of the qualities of the external world. As it has come out from the study, this is faulty because sense data and real experiences assume private and public status respectively. Thus one can not be able to effectively discern the state of mind of another and light their individual thoughts to this.
The inherent subjectivity disqualifies the former as a credible source. Russell’s preposition of representative realism is credible as it is only from observations that humans can develop accurate perceptions of the events, properties and objects in the external world. Where this is not possible, the sensory representation of the world can go a long way in enhancing objective perceptions. This assumption is also consistent with Descartes’ point of view with regards to critical realism. I strongly, agree with Russell that the understanding of the objective external world can not be entirely based on sense data.
Work Cited
Russell, Bertrand. Mysticism and Logic. London: Unwin Books, 1917.
Epilepsy and How it Occurs in Children
Epilepsy and How it Occurs in Children
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Epilepsy and How it Occurs in Children
Epilepsy
Epilepsy is a condition of the brain that is manifested after sudden and recurrent discharge of abnormal quantities of cerebral neurone transmitter substances creating errors in signal transmissions that result in seizures. Seizures occur as a result of the errors in signal transmission after material or significant alterations such as those caused by abnormal paroxysmal neurone discharge levels (Engel, Taylor and Trimble 2008, p2077). Generally, a manifestation of a seizure is accompanied by drastic brain function breakdown which can be on different levels of expression ranging from weird sensations affecting behavior at its best to sudden violent muscular contractions that may cause complete loss of body control or unconsciousness at its worst. As an illustration of heavy loss of brain functionality at such instance of a seizure attack, victims may experience violent body shakes, fall down and severely bit their tongues. Epilepsy is not a brain disease itself but an expression of a symptom of a number of conditions that could range from injury damage to brain tissue, unusual brain development, brain disease and the cause is elusive in many diagnosis cases leaving a huge gap for research in such cases (Scambler 1989, p1).
Causes of epilepsy in children or in adults are as speculative as it can be due to the several predisposing factors and confidence of diagnosis and attribution can be difficult. As highlighted above, epilepsy is not a disease in itself and it can therefore be used to probe cerebral conditions or diseases that may be involved but there is a knowledge gap for certain isolated dead-end cases. According to major literature as Aicardi, Engel and Pedley (2008, p2116) reckon, the several forms of epileptic seizures that can be diagnosed largely depend on the origins or causes, some of which the author highlights including; exposure to chemoconvulsants and toxins, genetic predisposition, congenital malformations, brain tumors, brain infections, acquired metabolic malfunctions and degenerative disorders among many others. In alcoholic adults, it has been reported that chronic alcoholism can trigger eventual degeneration of brain neurones consequently resulting in epilepsy.
Epilepsy in Children
Cognizant of the fact that the above highlighted predisposing factors of epilepsy causation are largely acquired, it may be important to isolate certain cases that can be observed only in children. As an illustration, it may be difficult to expect epileptic expression in children as a result of alcoholism. The mechanism of expression of epileptic conditions in children may therefore be different since the onset is at an earlier stage in life than in life, hence the different set of predisposing factors and the subsequent difference in the type of epilepsy in children. The bulk of literature around epileptic conditions in children is built around the premise that brain development anomalies constitute the biggest threat to children brain conditions such as epilepsy and autistic spectrum of brain conditions. According to Brooks-Kayal (2011, p14), there is a direct link between developmental brain disorders and epilepsy for the obvious reason that the two conditions are as a result of impairment in brain functionality. The author approximates the occurrence of epilepsy in autistic or developmental malfunctioned cases in children at 30 per cent to illustrate the connection that other major brain conditions have with epilepsy.
The similarity in the pathological functioning of these sets of brain conditions offers explanation to their occurrence (Brooks-Kayal 2011, p18). According to the author, it is a widely acceptable premise that the involvement of all these conditions in the disruption of transmission of nervous impulses at the synapses may be the causative threshold that characterizes their manifestation. Usually, as the author observes, the disorders seemingly affect the flexibility of the synaptic physiology manifesting a developmental disruption of the nervous functionality of excitation and inhibition of the synapses. This is a common phenomenon in developmental conditions such as Fragile X Syndrome, Tuberous Sclerosis Complex and Rett’s Sundrome , among many other brain developmental conditions. Such impairments during development result in the neuroligin and neuropilin 2 gene mutations whose expressions cause Autistic Syndrome Disorders, Intellectual Developmental Disabilities and epilepsy. Similarly, the development of epilepsies in a child may cause the development of other intellectual and development conditions due to the impairment of synaptic flexibility involved in epilepsy which act as their triggering factor.
Epileptogenesis or the process of development and expression of epilepsies takes months to years depending on the nature of the precipitating event that eventually causes stabilization of the seizure eliciting mechanisms. The ultimate stage of epileptogenesis is the impact on the respective genes usually in form of post translational modification in the preparation of the condition expression for the condition in the child. Expression occurs after transcriptional changes followed by the degeneration of normal neurones in the brain. Initial stages of expression begin with the generation of new set of abnormal neurones, reorganization of the neurones and gliosis which get established and stronger as the spontaneous seizures continue to occur (Baram et al. 2002, p4592). As illustrated, these changes are somewhat permanent and are difficult to be reversed if the extent of the damage is beyond reparable level. The brain experiences changes in cellular composition as mutated neural cells replace the inflammation and death of normal brain cells that otherwise eventually lose their functionality. As a result, the brain experiences abnormal control of excitatory and inhibitory mechanism of neurotransmitter substances that is manifested by erratic regulation and modulation of synaptic activities. It however is unclear under what conditions epileptic seizures occurring in children manifest remission as the children grow, contrary to expectations of the above irreversible characterization given to epilepsy by Brooks-Kayal (2011) and Baram et al. (2002).
Child Epilepsy Categorization
Following the guidelines of the International League Against Epilepsy (ILAE), it is possible for pediatricians and health professionals to classify epileptic conditions for a better approach in management (Wilmshurst 2004, p429). According to the author, there are several factors that can be applied in the categorization of the conditions which manifest epileptic spectrum of conditions and their severity must be distinguished in order to devise the best intervention to assist the child to live a near-to-normal life. Three major categories of the ILAE categorization criteria give three high impact epilepsy conditions namely the Paroxysmal Events, Focal Epilepsy and Generalized Epilepsy. Under paroxysmal events, there are four sub-categories of epileptic attacks which include firstly the reflex anoxic attacks which are characterized by breathing difficulties intermitted by crying among toddlers to 6 year olds. Secondly, syncope category involves fainting and is experienced by all children groups but is commonest among adolescent girls. Thirdly, benign paroxysmal vertigo experienced by toddlers where frightening episodes that cause paleness appear resulting to silent clinging to caretakers with cases of vomiting also being reported. Fourthly, pseudoseizures are manifested through rolling on the ground but not necessarily as a result of full blown epilepsy. This category may be as a result of psychological diagnoses such as abuse and exclusion (Wilmshurst 2004, p430).
The second category of epileptic categorization is referred to as focal epilepsies that are the commonest occurring from 8 to 12 years onwards. First subcategory is referred to Benign Focal Epilepsy of Childhood (BFEC) whose triggering factor is usually sleep interrupted by facial twitches that capture the child causing inability to respond vocally while the seizure lasts but usually for a short while. This subcategory is usually resolved through remission after adolescence. The second subcategory of focal epilepsies is referred to as Benign Epilepsy with Occipital Paroxysms (BEOP) which is also triggered by sleep usually lasting longer than BFEC, usually differentiated by severe headaches, temporary blindness, nausea and scans illustrate occipital excitation.
The third category involves generalized epilepsies has six subcategories which include Childhood Absence Epilepsy (CAE), Juvenile Myoclonic Epilepsy (JME), Atypical Absences, Tonic Seizures, Myoclonic seizures and Drop Attacks. CAE begins from 4 to 6 year olds with brief automatisms and unresponsiveness that are cleared before onset of adolescence. JME is triggered by light sensitivity upon awakening from sleep resulting in epileptic attack manifesting myoclonus activity from sleep. Atypical absences manifest affected cognition after exposure to a number of certain epilepsy triggering agents with prolonged features. Tonic seizures are strong in manifestation likely to affect autonomic nervous system. Myoclonic seizures are short spasms that affect the entire body that can range from simple impact to severe drops. Drop attacks express full epilepsy syndromes with short lived stiff to slump falls without after-fall drowsiness. A fourth category exists but it is not as important as the above three categories since the manifestations as per the title are ere epilepsy syndromes that mildly affect infants to 2 year old children (Wilmshurst 2004, p431).
Timing of Epileptic Attacks in Children
The attack on a child by seizures usually results in the suspicion of epilepsy, which could not be the case across all occurrences. Seizures can attack children due to exposure to certain conditions that are generally reversible and that cause nervous complications. Some of the commonest mild factors triggering seizures in children include hyperthermia, general body electrolyte imbalance and a number of biochemical imbalances including hypoxia. Epilepsy becomes manifest if more seizures occur after the first one and if the seizures occur on a repetitive fashion (Ackermann and Toorn 2011, p142). There are preconditions that affect the expression of seizures and epilepsy which can be monitored for the management of the attacks.
In order to determine when seizures amount to epileptic attack, a child needs to have medical examination from a medical professional. Generally, a large group of seizures can be managed by a general practitioner since they constitute common disorders that do not require specialized medical care. However, recurrence of seizures requires special diagnosis using specialized procedures such as EEG (Electroencephalographic), GEFS + (Generalized Epilepsy with Febrile Seizures Plus) and SMEI (Severe Myoclonic Epilepsy in Infancy). Other diagnosis techniques such as neuroimaging may be necessitated for higher degrees of accuracy in the detection of the specific condition. Pediatric intervention in the diagnosis is very important since the expression of the child in describing the nature of attack may be compromised by age and other factors. The input of pediatric intervention in dealing with epilepsy and related attacks is usually recommended by the ILAE instead of general practitioners unless it involves the management of general disorders without special complications.
Psychological Issues in Children with Epilepsy
As highlighted above regarding the nexus between brain functionality and epileptic conditions, it implies that children suffering from epilepsy and other brain development conditions are exposed to some form of social and psychological difficulties. Firstly, the diagnosis and treatment of epileptic conditions requires specialized attention from pediatrician or neurologist with similar expertise which may difficult for the family to deliver. The mere treatment from specialized professional and maybe specialized facilities may amount to some level of stigma for the child and the family. Generally, epileptic children are usually compromised in term of their brain development which extends to their learning and intellectual development (Brooks-Kayal 2011, p13). As a result of the complication thereon, there is a high chance that people may perceive them as antisocial and mentally retarded which negatively affects their psychological self-outlook.it is difficult for children to have a normal life among other normal children when epileptic conditions disrupt the life of the child, which makes it a socially disturbing phenomena that affects emotional development.
Psychological conditions are four times more common in epileptic children than in normal children (Lalkhen and Spangenberg 2006, p60). Due to their awareness that they have special needs, their presence of epileptic children among normal people may force them to feel inadequate and embarrassed of their condition. Behavioral displays of fearfulness, dependency and anxiety may trigger negative psychological attitudes among these children, with cases of withdrawal from social limelight likely to be reported. According to Lalkhen and Spangenberg (2006, p60), there is a high possibility of social isolation, low self esteem and future dependence that affects important life decisions made by these children. According to the author, children suffering from epilepsy have a higher tendency to drop out of school due to low self-image as a result o damaged psychological development.
At the family level, children with epilepsy may present a challenge to the members of the family as special attention must be kept on them. Frustration and shock are reported of parents whose children are diagnosed with epilepsy. Parents are also psychologically affected when they experience the attacks on their children and the impact is damaging to the whole family. Taking care of the child as a person with special needs is also psychologically draining for such parents, when compared with the setting of taking care of a normal child. According to Lalkhen and Spangenberg (2006, p61), the roles of the family members are affected due to the fact that the care of the child is a priority for everyone. Parents may neglect their other healthy children due to the psychological impact that the epileptic attacks present to the parents.
Treatment and Management
Drug therapy to cases of child epilepsy is only allowed in confirmed diagnoses of cases with prescription ranging from case to case depending on the manifestation of epileptic attack. Epilepsy has different types of routine treatment regimens which facilitate control of severe seizures and the damages they can cause. Regimens such as phenobarbitone are commonly suded around the world on a daily dosage to confirmed cases of epilepsy (Magasi, Ntsanwisi and Rataemane 2011, p57). Side effects may be experienced in certain regimens on older age groups that on the contrary perform better on younger age categories. Prescription s therefore supposed to be followed as directed by the physician. There are other second-line regimens such as topiramate and vigabatrin among other drugs but their usage is dependent on the response that a patient makes to treatment. Other drugs of choice include biotin, pyridoxal derivatives, and acetazolamide (Wilmshurst 2004, p432). Generally, withdrawal of treatment is regressively prescribed to facilitate coping with the withdrawal shock. Other interventions include ketogenic diets, antenatal gene therapy and surgery.
As mentioned earlier, some forms of epilepsy are complex and may permanently and severely impair the functioning of the brain resulting in psychological complications. To assist the child to cope with the challenge, it is advisable to facilitate psychological support and counseling for the child and the entire family. Medical professionals dealing with the conditions must assist the parents and family members to approach the condition with the appropriate frame of attitude and avoid psychological distress. Assisting the family and the child to come to terms with the condition may facilitate development of the child since trauma and stigma coping will have been facilitated. The child can be assisted to face such challenges with a bold and stronger attitude enabling establishment of a strong foundation in terms of psychological and social development (Lalkhen and Spangenberg 2006, p63).
Conclusion
Epilepsy presents a class of brain disorders that present difficult diagnosis and management challenges that require the input of a pediatrician or neurologist with child care specialization. Manifestation of seizures of different kinds must be distinguished from pathological presentation of epilepsy which has a distinct development process unlike seizures that may be triggered by simple physiological functions breakdown. Diagnosis of epilepsy and the appropriate categorization is important in the determination of the appropriate intervention to be adopted. Psychological trauma associated with brain conditions imply that assistance must be availed to assist children and families to cope with social challenges of the condition. Although epilepsy at childhood may present a permanent disorder, there are several mysterious phenomena observed in the condition such as natural remission and complete disappearance that still intrigue medical pediatric interventions and only future research can shed light to explain such phenomena.
References
Ackermann, S. & Van Toorn, R. (2011) Managing First-Time Seizures and Epilepsy in Children. CME, vol. 29, no. 4, pp142-148
Aicardi, J., Engel, J. & Pedley, T. (2008) Epilepsy: A Comprehensive Textbook, Vol. 1. Philadelphia, PA: Lippincott Williams & Wilkins
Baram ,T. Z., Bender, R. A., Brewster, A., Chen, Y., Dube, C. & Eghbal-Ahmadi, M. (2002) Developmental Febrile Seizures Modulate Hippocampal Gene Expression of Hyperpolarization-Activated Channels in an Iso-Form- and Cell-Specific Manner. Journal of Neuroscience, vol. 22 pp.4591–4559
Brooks-Kayal, A. (2011) Molecular Mechanism of Cognitive and Behavioral Comorbidities of Epilepsy in Children. Epilepsia, vol.52, no. 1, pp.13-20 Doi:10.1111/j.1528-1167.2010.02906.x
Engel, J., Taylor, D. & Trimble, M. (2008) “Neurology of Behavioral Disorders” in Aicardi, J., Engel, J. & Pedley, T. Epilepsy: A Comprehensive Textbook, Vol. 1. Philadelphia, PA: Lippincott Williams & Wilkins
Lalkhen, N. & Spangenberg, J. J. (2006) Children with Epilepsy and their Families: Psychological Issues. SA Fam Pract, vol. 48, no. 6, pp60-63
Magasi, D., Ntsanwisi, V. & Rataemane, S. (2011) Alternative Psychosis (Forced Normalization) in Epilepsy. SAJS, vol. 17, no. 2, pp.565-59
Scambler, G. (1989) Epilepsy. London, UK: Routledge Publishers
Wilmshurst, J. M. (2004) Approach to Epilepsy in Childhood. Epilepsy, vol. 22, no. 8, p427-433
Epidemology And Toxicology-Diesel Particulate
Epidemology And Toxicology-Diesel Particulate:
By (Insert both names)
(Name of class)
(Professor’s name)
(Institution)
(City, State)
(Date)
Table of Contents…………………………………………………………………………………………………Page
Executive Summary………………………………………………………………………………………………..1
Introduction…………………………………………………………………………………………………………….4
Literature Review……………………………………………………………………………………………………………..4
Results and Discussions…………………………………………………………………………………………………..6
Conclusion and Recommendation………………………………………………………………………………………9
References…………………………………………………………………………………………………………….10
Executive Summary:
The Government organ has considered establishing a workplace diesel particulate exposure standard and has issued letters to all stakeholders to make proposals on feasible exposure standards of 0.1mg/m3 worked out as elemental carbon (EC). Some of their responses are below:
Stakeholder Recommendation
Unions levels of 0.1mg/m3 is too high
Management Level of 0.1mg/m3 is too low
Professional societies 0.1mg/m3 levels may be accepted
Government rep. Recommended 0.001mg/m3- 0.15mg/m3 EC
Since there was no agreement arrived at, the Government organ has contacted a faction of professionals to review all the toxicological and epidemiological data and propose an exposure standard recommendation and that forms the basis of the report.
Introduction
The health concerns of exposure to soot (diesel particulate) have been the topic of scientific discussing for a significant period of time and have ended up in the contemporary Exposure Standards promulgation by certain overseas nations. Studies from the USA and Canada show that the diesel particulate airborne levels in metaliferous mines are extremely in excess of the new standards. Surveillance carried out by researchers at 6 Australian metaliferous underground mines also show that some exposures are greater than the standards and in a number of cases high above the levels of formerly documented from the Australian coal underground industry. An assessment of the exposure levels of the Australian and some oversea statistics from similar functions and also ranks the statistics against overseas proposed or current exposure standards, explored. An outline of the control mechanisms presently available within the metaliferous underground production is also illustrated.
Literature Review
The monitoring methods of Diesel Particulate:
Emissions of diesel are composed of compound mixture of gases and particulates. The gaseous compound comprises oxides of carbon (CO2; CO), water vapor, Nitrogen Oxides (NO2, N2O4, and NO) explosive organic complex originating from the process of combustion and the un-reacted gaseous. The “soot” or particulate compound is a complex mixture comprising of hard carbon cores generated from the combustion process alongside other series of adsorbed organic substance that can make up 65% of the accumulation. Over 90% of these particles of Carbon are inhalable, with aerodynamic breadth of 1mc. Or less and thus, can enter the lung’s deepest region.
As a result of this tiny particle mass, the diesel particulate can be easily isolated from the aerosol mineral dust contained in mine environs applying a two-phase separator to initially gather the inhalable size proportion and thereafter, crack it into super and sub micron proportions. The sub micron proportion has more than 85 per cent of the diesel particulate, and is thus, subject to carbon scrutiny within an optical thermal furnace or (DPM mg/m3) gravimetric analysis (Rodgers 1996).
Though sampling technique and carbon species examination have been standardized and implemented in the US laws, there are only a handful of laboratories that perform those kinds of analysis within the USA (MSHA 2001 & NOSH 1995).
The Health Impacts of Diesel “Soot” and the Exposure Standards:
The health impacts of exposure to emissions of diesel have been debated for a long time. Animal researches involving long run exposures of excessive concentrations of particulates of diesel produce series of cancerous and non cancerous respiratory impacts for example, chronic inflammation, obstructive and restrictive lung patterns of lung functions. Nonetheless, human epidemiological researches on miners are not providing consistent or strong evidence for such non-malignant, chronic effects. The support for a relationship between diesel particulate and human cancers is uncertain with certain works depicting an increased risk and some showing no added risk. Of specific interest to the mining society is the research of Australian Coal miners which did not indicate any increased lung cancer risk, despite the miners being exposed to a mixture of diesel particulates and coal dust (Davies 2009).
Various mining and health authorities have viewed to appropriate to establish exposure standards of the particulates of diesel. The generally recommended standard industry developed by the (US ACGIH TLV),is 0.050mg/m3 Diesel emission particulate computed as the submicron proportion (=to {TCM} Total Carbon measurement. (Notice for the Change Intended 2000).
US MSHA in the statutes have Proposed 0.16 mg/m3 Rulemaking Total Carbon for non-metals and metal mines. Coal mines have no nominal exposure value but a requisite for the application of control technique to impact a 95% decrease of particulates of diesel in raw emission levels.
The NSW regulations for mataliferous mines indicated limit for diesel particulate at 2 mg/m3 as computed using specific techniques, nonetheless, the peoples’ experience are that these levels extreme respiratory track and eye irritation would be encountered. The Mineral council of NSW based on the study findings has recommended 0.2mg/m3 levels to reduce irritation experiences.
Results and Discussion:
Lung Cancer Exclusion:
(MSHA, 2001b), studied 47 epidemiological works and established that 41 of the reviewed works had some levels of association between the workplace exposure to the particulate of diesel and an excessive occurrence of cancer. Nonetheless, a number of these researches had limited statistical control and these could be due to inclusion of comparatively less workers or perhaps they had insufficient period of latency or even inadequate follow up allowance. (MSHA), thus established that that 0.64mg/m3 DP mean concentration exposure in 45 years period would develop into in a relative risk of 2.0 for the cancer of the lung.
Respiratory Inflammation and Irritation:
The (US EPA, 2002) carried out a health evaluation for the exhaust of diesel engine. They confirmed that chronic effects in view of health, for instance, bronchial, eye and throat irritation, nausea, phlegm and cough were manifested. In light of acute non-cancer effects of the respiratory they established, from the studies of animals, the likelihood of acute respiratory illness in humans. From their studies, they also established that lung cancer was manifested, although they were not able to describe an appropriate dose-response statistics to deliver risk qualitative assessment. According to the interpretation of the epidemiological and toxicological statistics, the regulatory bodies in Canada, USA and Europe have confirmed that there is adequate evidence to show that diesel soot poses an elevated risk of cancer of the lung, yet still a complete quantification of potency stays uncertain.
Studies from 6 metaliferrous underground mines have been conducted and the findings summarized in the table 1 below.
Table 1:
Mine DPM mg/m3 EC mg/m3 TC mg/m3
Cu extraction 0.11- 1.30 0.042 – 0.372 0.112 – 0.572
Pb/Zn development 0.19 – 0.75 – –
Pb/Zn development 0.12 – 0.38 0.060 – 0.190 0.155 – 0.293
Pb/Zn extraction 0.07 – 0.56 0.021 – 0.265 0.060 – 0.456
Pb/extraction 0.05 – 0.60 0.010 – 0.180 0.050 – 0.420
Pb/extraction 0.16 – 0.57 0.017 – 0.418 0.130 – 0.532
Sandstone tunnel – 0.010 – 0.210 0.050 – 0.320
There is significant inconsistency in the exposures dependent on machinery type and working condition both in every mine but also from mine to mine. The greater exposures normally occur when there is a huge machinery operating hard and also in circumstances where steep inclines, poor roads, multiple vehicle activity, stretching hauls with wide huge loads and or when the engine is poorly maintained.
There are similar forms of exposure in Queensland and NSW coal underground mines; nevertheless, in metaliferous underground plants the exposures are very high because of the loads carried and massive engine sizes.
As a result of the through ventilation structures deployed in the metaliferous industry, a lot of other mine workforces are not directly engaged with heavy machinery diesel but who have the likelihood of getting exposed to excessive levels of diesel soot.
Control techniques:
The application of techniques to control diesel soot levels within the Australian metaliferrous underground mines has been minimal. Overly, the industry has put in place considerable dependence on gas testing of untreated exhaust, Personal Protection Equipment (PPE) and ventilation as a method for controlling diesel soot. Some modern equipment is fixed with regenerative particulate traps. Dependence on these two methods of PPE and ventilation is reasonable since traditional ceramic filters were tested at considerable cost with very disappointing results. The other control technique which has been the topic for discussion within the industry is the quality of fuel. Once more some factions of the industry have witnessed the introduction of fuels with low sulphur as the solution to the quandary, and while it brings some settlements, it by no chances the ultimate solution.
A recent research by the Labor Department (USA) (MSHA 2007) on the pragmatic ways to minimize the exposure to emissions of diesel (comprising particulates) in mines pointed out several important measures. A number of these have been examined by the Australian mines industry with such below results:
Low emission engines:
Developments in the engine design over the past ten years have resulted to sets with more standardized fuel mixtures and high rate of combustion. Engines that are controlled electronically provide systems through which the volume of fuel infused into the cylinders is precisely metered for the weight on the engine. This offers the advantage of decreased consumption of fuel and less emission. The scope of fewer emissions has been described by a practice carried out at the Queensland mines whereby the trucks designed in electronically and normal controlled engines towing up a decrease were monitored. The findings in table 2 show a decrease of about 31-43 % dependant on the days’ duty cycle. The exercise took three days and 11 trucks were involved.
Table 2:
Engine type Average elemental carbon Concentration (mg/m3) % age Reduction
Caterpillar 0.14 – 0.18 –
Detroit 0.08 – 0.125 31 – 43
This data is in conformity with a similar study conducted in Canada where decline was approximated to be at 50%.
Personal Protective Equipment and Work Practices:
Dependency on respiratory protection to manage exposures of workers to diesel soot cannot be condoned; nonetheless, pragmatic experiences may imply that such devises will be required for use control certain circumstances. One situation that has been experienced happens when loaders are managed remotely to load stretched stoops. In those situations, show a considerable increase to exposure. Job practices (for instance, idling engines; aggressive driving) have also been indicated to heighten to level of diesel soot within the atmosphere of mines.
Conclusion and Recommendation
Based on the epidemiological and animal studies, a majority of informed professionals will acknowledge that, diesel soot is a latent carcinogen. A lot would also have issues concerning the level of latency tagged on diesel soot by certain regulatory bodies. It is apparent that with lots of low latent substances the concern may never be entirely addressed this is because of lack of adequate exposure statistics and power over confounders in the populations studied. There is minimal skepticism that this field of health debate will go on for some duration within the regulatory and scientific community. A trend is developing within the workplace hygiene society to undertake a practical approach to control and measure exposures of the malodorous and noxious emissions with no effort to describe a dose response based on the standard exposure.
More studies within the meteliferrous mining sector in regards to the diesel particulate is needed if worker exposures are to be minimized to my proposed standards of o.1mg/m3 in a cost effective fashion.
References:
US Department of Labor Mines Safety and Health Administration, Diesel Particulate matter Exposure of Underground Metal and Non-Metal Miners, Federal Registry, 77. No. 15, January 27, 2010.
Davies, B (2009). Application of an Elemental Carbon Analyzer to the measurement of particulate levels from diesel vehicles. ACARP Report C715.
ACGIH , (2005) and BEIs OH, American Conference of Governmental Industrial Hygienists (17) , 67-7.
Birch, E. (1989). Analysis of carbonaceous aerosols inter-laboratory comparison. Analyst. 213: 672-67.
BOHS, (1981), Diesel fume. BOHS Hygiene Standards Committee: (24),254-78