Table of Contents

Abstract: The goal of this study was to measure ultrafine particle concentrations with diameters less than 1 μm emitted by diesel buses and to assess resulting human exposure levels. The study was conducted at the Woolloongabba Busway station in Brisbane, Australia in the winter months of 2002 during which temperature inversions frequently occurred. Most buses that utilize the station are fuelled by diesel, the exhaust of which contains a significant quantity of particle matter. Passengers waiting at the station are exposed to these particles emitted from the buses. During the course of this study, passenger census was conducted, based on video surveillance, yielding person-by-person waiting time data. Furthermore, a bus census revealed accurate information about the total number of diesel versus Compressed Natural Gas (CNG) powered buses. Background (outside of the bus station) and platform measurements of ultrafine particulate number size distributions were made to determine ambient aerosol concentrations. Particle number exposure concentration ranges from 10 and 40 to 60% of bus related exhaust fumes. This changes dramatically when considering the particle mass exposure concentration, where most passengers are exposed to about 50 to 80% of exhaust fumes. The obtained data can be very significant for comparison with similar work of this type because it is shown in previous studies that exhaust emissions causes cancer in laboratory animals. It was assumed that significant differences between platform and background distributions were due to bus emissions which, combined with passenger waiting times, yielded an estimate of passenger exposure to ultrafine particles from diesel buses. From an exposure point of view, the Busway station analyzed resembles a street canyon. Although the detected exhaust particle concentration at the outbound platform is found to be in the picogram range, exposure increases with the time passengers spend on the platform along with their breathing frequency.

Abstract: Most arsenic cancer risk assessments have been based solely on epidemiological studies to characterize the dose-response relationship for arsenic-associated cancer and to perform risk calculations. However, current epidemiological evidence is too inconsistent and fraught with uncertainty regarding arsenic exposure to provide reliable estimates. This makes it hard to draw a firm conclusion about the shape and slope of the dose-response relationship from individual studies. Meta-analysis is a statistical approach to combining results across studies and offers expanded opportunities for obtaining an improved dose-response relationship. In this study, a meta-analysis of arsenic studies was conducted by combining seven epidemiological studies from different regions to get an overall dose-response relationship between the amount of arsenic intake and the excess probability of bladder cancer. Both the fixed-effect and random-effect models were used to calculate the averaged coefficient of the linear-logistic regression model. A homogeneity test was also conducted. The final product of this research is an aggregated dose-response model in the range of empirical observation of arsenic. Considering the most recent arsenic MCL (maximum contaminant level, i.e. 10μg/L), the associated bladder cancer risk (lifetime excess probability) at this MCL is 2.29 10^-5.

Abstract: Cadmium (Cd) is frequently used in various industrial applications and is a ubiquitous environmental toxicant, also present in tobacco smoke. An important route of exposure is the circulatory system whereas blood vessels are considered to be main stream organs of Cd toxicity. Our previous results indicate that cadmium chloride (CdCl₂) affects mean arterial blood pressure in hypertensive rats. We hypothesized that Cd alters the intracellular calcium transient mechanism, by cadmium-induced stimulation of MAPKs (ERK 1 & 2) which is mediated partially through calcium-dependent PKC mechanism. To investigate this hypothesis, we exposed primary cultures of vascular smooth muscle cells (VSMCs) from wistar kyoto (WKY) and spontaneously hypertensive rats (SHR) to increased concentrations of CdCl₂ on cell viability, expression of mitogen-activated protein kinases (MAPKs/ERK 1 & 2), and protein kinase C (PKC) which are activated by Cd in several cell types. The results from these studies indicate that CdCl₂ decreased cell viability of both SHR and WKY VSMCs in a concentration dependent-manner. Viability of both cell types decreased 33±5.3 (SHR) and 39±2.3% (WKY) when exposed to 1 μM CdCl₂, whereas, 8 and 16 μM reduced viability by 66±3.1 and 62±4.5% in SHR cells. CdCl₂ increased ERK 1 & 2 in a biphasic manner with maximum increase occurring when cells are exposed to 1 and 4 μM in SHR VSMCs, whereas, a reduction in ERK 1 and 2 is observed when WKY cells are treated with 2 μM. The results also indicate that CdCl₂ increased PKC a/ß in both SHR and WKY VSMCs with a greater increase in expression in SHR VSMCs. In addition, the [Ca²⁺]i chelator, BAPTA, suppressed the CdCl₂ effect, whereas, the PKC inhibitor, GF109203X, reduced the CdCl₂ induced-effect on PKC expression. The present studies support the hypothesis that Cd can be a risk factor of hypertension through dysfunction of vascular smooth muscle cells under certain conditions.

Abstract: The aim of this study was to estimate the activity of superoxide dismutase (SOD) and catalase in erythrocytes and malondialdehyde (MDA) in plasma of battery manufacturing workers (BMW) of Western Maharashtra (India) who were occupationally exposed to lead (Pb) over a long period of time (about 15 years). This study was also aimed to determine the Pb intoxication resulted in a disturbance of heme biosynthesis in BMW group. The blood Pb level of BMW group (n = 28) was found to be in the range of 25.8 – 78.0 μg/dL (mean + SD, 53.63 + 16.98) whereas in Pb unexposed control group (n = 35) the range was 2.8 – 22.0 μg/dL (mean + SD, 12.52 + 4.08). The blood level (Pb-B) and urinary lead level (Pb-U) were significantly increased in BMW group as compared to unexposed control. Though activated d- aminolevulinic acid dehydratase (ALAD) activities in BMW group did not show any significant change when compared to control group but activated / non activated erythrocyte – ALAD activities in BMW group showed a significant increase. Erythrocyte- zinc protoporphyrin (ZPP), urinary daminolevulinic acid (ALA-U) and porphobilinogen (PBG-U) of BMW groups elevated significantly as compared to control. A positive correlation (r = 0.66, p< 0.001) between Pb-B and ALA-U were found in BMW group but no such significant correlation (r = 0.02, p> 1.0) were observed in control group. Hematological study revealed a significant decrease of hemoglobin concentration, packed cell volume (%) and other blood indices and a significant increase of total leucocytes count in BMW group in comparison to control group. The serum MDA content was significantly increased (p< 0.001) and the activities of antioxidant enzymes such as erythrocyte- SOD (p< 0.001) and erythrocytecatalase (p< 0.001) were significantly reduced in BMW group as compared to control group. A positive correlation (r = 0.45, p<0.02) between Pb-B and serum MDA level was observed in BMW group (Pb-B range 25.8 – 78.0 μg / dL) but such significant correlation did not notice in control group (Pb-B range 2.8 – 22.0 μg / dL).The study clearly showed an adverse effect of heme biosynthesis and imbalance of pro-oxidant / antioxidant status in lead exposed battery manufacturing workers resulting in increase in lipid peroxidation associated with decrease in erythrocyte-SOD and erythrocyte-catalase activities.

Abstract: The reemerging field of Medical Geology is concerned with the impacts of geologic materials and geologic processes on animal and human health. Most medical geology research has been focused on health problems caused by excess or deficiency of trace elements, exposure to ambient dust, and on other geologically related health problems or health problems for which geoscience tools, techniques, or databases could be applied. Little, if any, attention has been focused on the beneficial health effects of rocks, minerals, and geologic processes. These beneficial effects may have been recognized as long as two million years ago and include emotional, mental, and physical health benefits. Some of the earliest known medicines were derived from rocks and minerals. For thousands of years various clays have been used as an antidote for poisons. “Terra sigillata,” still in use today, may have been the first patented medicine. Many trace elements, rocks, and minerals are used today in a wide variety of pharmaceuticals and health care products. There is also a segment of society that believes in the curative and preventative properties of crystals (talismans and amulets). Metals and trace elements are being used in some of today’s most sophisticated medical applications. Other recent examples of beneficial effects of geologic materials and processes include epidemiological studies in Japan that have identified a wide range of health problems (such as muscle and joint pain, hemorrhoids, burns, gout, etc.) that may be treated by one or more of nine chemically distinct types of hot springs, and a study in China indicating that residential coal combustion may be mobilizing sufficient iodine to prevent iodine deficiency disease.

Abstract: Cu²⁺ and butylic ester of 2,4-Dichlorophenoxyacetic acid as Esternon Ultra (2,4-D) toxicity on Bufo arenarum embryos were evaluated by means of a short-term chronic toxicity test (AMPHITOX). The NOEC values for Cu and 2,4-D were 0.02 mg/L and 2 mg/L respectively. The toxicity profile curves for Cu and 2,4-D were reported. The interactions of the metal and the herbicide were evaluated by combined treatments with different concentrations of Cu and 2,4-D. Although in all cases, a synergistic effect between these chemicals was observed, the combination of concentrations exerting low level effects in isolated treatments resulted in more adverse embryonic survival. Considering that both products are extensively used in agroecosystems, this fact could be of concern for non target species like amphibians.

Abstract: Polycyclic aromatic hydrocarbons (PAHs) are a class of genotoxic environmental contaminants. We have long been interested in determining the mechanisms by which PAHs induce genotoxicity. Although the metabolic activation of PAHs leading to biological activities has been well studied, the photo-induced activation pathway has seldom reported. In this paper, we review the study of photoirradiation of PAHs with UVA irradiation results in (i) cytotoxicity and DNA damage (ii) DNA single strand cleavage; (iii) formation of 8-hydroxy-2’-deoxyguanosine adduct (8-OHdG), and (iv) formation of lipid peroxidation. Evidence has been shown that these photobiological activities are mediated by reactive oxygen species (ROS).

Abstract: This study was designed to assess the impact of high particulate concentration on peak expiratory flow rate of lungs of sand stone quarry workers. The workers were engaged in different types of activities such as drilling, loading and dressing. These different working conditions had different concentrations of RSPM, leading to different exposure levels in workers. It was found that exposure duration and exposure concentrations were the main factors responsible for damage to the respiratory tracts of the workers. The particles were deposited at various areas of the respiratory system and reduced the peak flow rate. It was also revealed from the study that most of the workers suffered from silicosis if the exposure duration was more than 20 years.

Abstract: In big cities, the cost of treating wastewater is increasing with more stringent environmental requirements. Ionizing radiation technology for treating municipal wastewater may be an alternative to reduce treatment costs. In this paper, laboratory tests were carried out using different doses of radiation to treat wastewater samples collected from the AL-Rustamia wastewater treatment plant in Baghdad city. According to the results, irradiation by gamma radiation with a dose ranging from 100 to 500 krad was efficient in reducing some of the physical contaminants. The organic contaminants were degraded and reduced to about 12% of their original concentrations. Generally, irradiation technology could effectively modify the characteristics of the wastewater to such levels that are compatible with Iraqi disposal standards. The results of the study also showed that, an experimental pilot plant study is required to optimize the cost of wastewater treatment through the use of this technology.