Epidemiology and Toxicology - Diesel Particulate - Literature review Example

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. According (John 1993) Epidemiological works indicate serious and acute undesirable impacts of the particulate atmospheric contamination on the respiratory health particularly the individuals who are vulnerable to the bacterial infection. To deliver pragmatic epidemiologic statistical support, they established the impacts of (DEP) diesel exhaust particles, main ingredients within the particulate contaminant the injury of the lung linked to bacterial endotoxin in animals. 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. Irrespective of the absence of a definite dose response experience, relationship has indicated that when place of work exposure are managed under 0.1mg/g3 DP, the effect of irritation is greatly reduced. (AIOH) indicate that this level will develop in a lowered lung cancer findings if so, then effect of carcinogenic is real for the population. Due to lack of more precise data, the recommendation that AIOH supports 0.1mg/m3 DP exposure standard. 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 John. W, (1993) Air pollution and daily monitory in 6 US cities. Env. Review. (36) 56-98. Read More