Drinking water intake of arsenic (As) from private wells may represent a significant exposure pathway and induce oxidative DNA damage. We measured total As concentrations in hair and nails, and concentrations of the different species of As and its metabolites as well as 8-OHdG in urine of 110 non-smoking adults living in a rural region of the Province of Quebec, Canada. Significant differences in exposure biomarker levels were observed between individuals consuming drinking water with As levels of≤1.0,>1.0 –≤10 and>10 μ g/l. Multivariate linear regression analysis also showed a significant relationship between estimated daily drinking water intakes of As and biomarker levels. Conversely, 8-OHdG levels were not significantly related to daily drinking water intakes of As or to hair, nail or urinary exposure biomarker levels, according to multivariate linear regression analysis. Even at the relatively low levels of As found in well water of our participants, water consumption significantly increases their body load of As, as confirmed by multiple matrix measurements, which reflected exposure over different time frames. However, this increased internal As dose was not associated with higher oxidative damage to DNA as reflected by urinary 8-OHdG levels.

Beryllium (Be) is used in several forms: pure metal, beryllium oxide, and as an alloy with copper, aluminum, or nickel. Beryllium oxide, beryllium metal, and beryllium alloys are the main forms present in the workplace, with inhalation being the primary route of exposure. Cases of workers with sensitization or chronic beryllium disease challenge the scientific community for a better understanding of Be toxicity. Therefore, a toxicological inhalation study using a murine model was performed in our laboratory in order to identify the toxic effects related to different particle sizes and chemical forms of Be. This article attempts to provide information regarding the relative effectiveness of the environmental monitoring and exposure protection program that was enacted to protect staff (students and researchers) in this controlled animal beryllium inhalation exposure experiment. This includes specific attention to particle migration control through intensive housekeeping and systematic airborne and surface monitoring. Results show that the protective measures applied during this research have been effective. The highest airborne Be concentration in the laboratory was less than one-tenth of the Quebec OEL (occupational exposure limit) of 0.15 mu g/m(3). Considering the protection factor of 10(3) of the powered air-purifying respirator used in this research, the average exposure level would be 0.03 x 10(-4) mg/m(3), which is extremely low. Moreover, with the exception of one value, all average Be concentrations on surfaces were below the Quebec Standard guideline level of 3 mu g/100 cm(2) for Be contamination. Finally, all beryllium lymphocyte proliferation tests for the staff were not higher than controls.

Selenium is an important cofactor of various antioxidant enzymes and has been shown to enhance DNA repair in normal human fibroblasts. Oral selenium supplementation has also been shown to decrease the number of chromosome breaks in BRCA1 mutation carriers. Because the predisposition to cancer among BRCA1 mutation carriers may be linked to high rates of DNA damage and chromosome breakage, we evaluated the association between toenail selenium concentrations and three measures of DNA repair capacity (the single-cell alkaline gel electrophoresis (comet) assay, the micronucleus test, and the enumeration of gamma-H2AX nuclear foci) in female BRCA1 mutation carriers and in non-carriers. Toenail selenium levels were inversely associated with levels of chromosomal damage following exposure to gamma-irradiation, as assessed by the micronucleus test. This association was limited to women with a BRCA1 mutation (p = 0.03). Toenail selenium was not a significant predictor of DNA repair capacity, as quantified by either the comet assay or the number of gamma-H2AX foci, in carriers or in non-carriers. These results provide evidence for a possible protective effect of selenium against BRCA1-associated breast cancers.

Methylcyclopentadienyl manganese tricarbonyl (MMT) was used between 1990 and 2003 as an antiknock agent and as an octane booster in Canadian unleaded gasoline. Its combustion leads to Mn emissions. The objective of this research was to examine the variations in atmospheric Mn in Montreal (Canada) from 2001 to 2007, covering the period prior (2001–2003) to and following (2005–2007) MMT use. Three sampling stations were selected because of their proximity to roads with widely differing and well-known traffic patterns. Filters from 2001 to 2007 were obtained from the Montreal Urban Community. The first sample of each month was selected, and Mn analysis was performed by neutron activation analysis. Total suspended particulates (TSP) was calculated by weighing the filters before and after dust collection. Results show a significant decrease of Mn over time at each station, whereas TSP decreased significantly in two stations. Comparing atmospheric Mn during and after the period of use of MMT 2001–2003 vs 2005–2007 showed a significant decrease at all stations. For TSP, only one station showed borderline significant decline between these two periods. Overall, between the two periods, Mn and TSP decreased by 39% and 17%, respectively. These data suggest that the combustion of MMT led to an increase of airborne Mn of approximately 22%. These findings should help in decision-making processes concerning the use of MMT in gasoline in other countries.

Aluminum smelters produce in excess thousand of tons of spent pot lining (SPL) each year. CAlSiFrit technology is a recycling process in which spent pot lining (SPL) is recovered and transformed into commercial value-added products. Since SPL contains beryllium (Be), exposures encountered by workers may result in adverse effects. This study aimed to establish the level at which Be is present in the CAlSiFrit and to determine the chemical and physical characteristics of the Be-containing particles. Three samples of CAlSiFrit powder supplied by the recycling industry were analyzed using several methods in order to (1) detect and characterize Be-containing particles, (2) identify the Be chemical form, and (3) quantify the amount of other major chemical elements present. These methods were: inductively coupled plasma–mass spectrometry, instrumental neutron activation analysis, time-of-flight secondary-ion mass spectrometry (TOF-SIMS), analytical transmission electron microscopy (ATEM), and x-ray diffraction. Results show that the three samples have a similar chemical composition, with high concentrations, of Si, Ca, Al, Na, F, Fe, K, Mg, and Ti, in decreasing order. Be concentrations were low and totaled less than 3 ppm. The size of the areas where Be was detected by TOF-SIMS is approximately 0.3 μm or less in diameter. A large quantity of oxygen in the particles of dusts was observed. As the majority of elements present have a great affinity for oxygen, the presence of oxygen indicates that these elements are probably oxides. Finally, the particle size varied from approximately 0.05 to 1 μm. This is consistent with the interpretation of the TOF-SIMS results that suggest a size of approximately 0.3 μm or less for the particles containing Be. These results are important from the perspective that thousands of tons of CAlSiFrit, a supplementary cement material, might be produced and used.

In Canada, Methylcyclopentadienyl manganese tricarbonyl (MMT) replaced tetraethyl lead in gasoline as an antiknock agent from 1976 until 2003. The combustion of MMT leads to increased manganese (Mn) concentrations in the atmosphere, and represents one of the main sources of human exposure to Mn. The nervous system is the major target of the toxicity of Mn and Mn compounds. The purpose of this study was to investigate exposure‐response relationships for neuropathology and tremor, and the associated electromyogram (EMG), following subchronic inhalation exposure of rats to a mixture of Mn phosphate/sulfate particles. Rats were exposed 6 h per day, 5 days per week for 13 consecutive weeks at 30, 300 or 3000 µg m−3 Mn phosphate/sulfate mixture and compared with controls. Half of the rats had EMG electrodes implanted in the gastrocnemius muscle of the hind limb to assess tremor at the end of Mn exposure. Two days after the end of Mn exposure, rats were killed by exsanguination and Mn concentrations in the brain (caudate putamen, globus pallidus and frontal cortex) were determined by neutron activation analysis while neuropathology was assessed by counting neuronal cells in 2.5 mm × 2.5 mm grid areas. Increased Mn concentrations were observed in all brain sections at the highest level of exposure. The neuronal cell loss was significantly different in the globus pallidus and the caudate putamen at the highest level of exposure (3000 µg m−3). No sign of tremor was observed among the rats. In conclusion, exposure to a high level of Mn phosphate/sulfate mixture brought on neuropathological changes in a specific area of the brain; however, no sign of tremor was observed. Copyright © 2006 John Wiley & Sons, Ltd.

In Montreal (Canada), the mean annual atmospheric Mn concentrations between 1981 and 1990 were stable, followed by a decrease of almost 50% from 1990 to 1992. The reason for such a decrease in Mn is probably the shutdown of a large manganese alloy production plant in Beauharnois, approximately 25 km from Montreal. The objective of this study is to assess the level of air and soil contamination by Mn in the vicinity of this ferroalloy plant more than 10 years after its closure. Air and soil were sampled over 5 days at two and three sites, respectively. Site 1 was located 10 m NE of the closed plant, in the direction of the prevailing SW-NE winds. Sites 2 and 3 were at 50 and 800 m SE from the plant. Air samples were collected in order to determine total (MnT) and respirable (MnR). Soil samples were taken in the surface and subsurface strata. The results show that site 1 is extremely polluted with a mean Mn concentration in surface strata of 2,66,000+/-45,000 ppm and 2,83,000+/-23,000 ppm in the subsurface strata, while the average MnT and MnR are 21.9+/-13.7 and 3.5+/-3.9 microg/m(3), respectively. The explanation for this contamination is direct deposition on the soil of solid Mn-rich residue and atmospheric erosion of Mn particles. The situation should be remediated by the public authority with high priority.

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese (Mn), used since 1976 in Canadian gasoline as an octane enhancer. Its combustion leads to the emission of Mn particles. Several studies carried out by our research group have established a correlation between atmospheric Mn concentrations and automobile traffic density, suggesting that MMT in gasoline could play a significant role. This study aims to measure Mn concentrations in the air of the underground subway in Montreal (Canada) and to examine the relation with nearby surface automobile traffic density and, by extension, with the use of MMT in gasoline. Three subway stations were chosen for their location in different microenvironments with different traffic densities. Respirable (MnR<5 microm) and total Mn (MnT) were sampled over two weeks, 5 days/week, 12 h/day. For the station located in the lower traffic density area, relatively low levels of MnR and MnT were found, with averages of 0.018 and 0.032 microg/m(3), respectively. These concentrations are within the range of the background levels in Montreal. For the other two stations, the average concentrations of MnR were twice as high and exceeded the US EPA reference concentration of 0.05 microg/m(3). Although there may be several sources of Mn from different components of the subway structure and vehicles, no correlation was found between subway traffic and atmospheric Mn in the subway. Since the air in the underground subway is pumped directly from outside without filtration, our findings strongly suggest that the combustion of MMT in automobiles is an important factor.

Methylcyclopentadienyl manganese tricarbonyl (MMT: C9H7MnO3) is an organometallic additive that has been used since 1976 as an octane enhancer in Canadian unleaded gasoline. Very few studies have determined its atmospheric concentrations and only one study offers recent data on its ambient level. This preliminary study aims to assess atmospheric concentrations of MMT and respirable and total Mn (Mn(R) and Mn(T) in selected sites, at two underground car parks and one gasoline station, related to high levels of automobile traffic. It is also an investigation of the applicability of the current analytical method. In total, 34 air samples were collected using a Gil-Air portable pump during 4 consecutive days and then were analyzed by neutron activation analysis. The concentrations vary between 40 and 104 ng/m3 for Mn(R), 146 and 204 ng/m3 for Mn(T) and 6 and 128 ng/m3 for MMT (including ultrafine particulates, Mn(UF). Of the 12 Mn(R) results, 7 showed concentrations greater than the U.S. EPA reference concentration (RfC = 50 ng/m3). The ratios of Mn(R) to Mn(T) varied from 0.20 to 0.65 with a mean of 0.38. The results for MMT and Mn(UF) raise serious doubts about the specificity of the sampling and chemical analysis methodology proposed by the Occupational Safety and Health Administration (OSHA) for MMT in air.

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese (Mn) used in Canada as an antiknock agent and octane enhancer in gasoline. In a recent study, we measured the atmospheric concentrations of MMT at selected outdoor sites in Montreal. Results ranged from 0.18 to 25 ng m-3 (expressed as Mn) and do not reflect personal exposure levels. The highest values were obtained at a gas station (mean of 12 ng m-3). By extension, evaluation of the personal exposure of gas station attendants constitutes a promising area of research. In an earlier study, the sampling method used allowed the possibility that the samples could have included ultra-fine particles, which may have passed through the filters used, and the chemical analysis used (neutron activation) did not discriminate between MMT and other Mn compounds. The present study aims to validate an improved sampling method and to assess personal exposure of gas station attendants to MMT. The MMT recovery of the new sampling method was found to be 91.6%. The exposure of 13 gas station attendants was measured on 1 to 6 occasions each (n = 32). They were working in two busy gas stations located in Montreal and they were asked to wear a portable pump for 2 hr. The air was pumped through two tubes in series filled with the adsorbent Tenax TA™, with glass wool plugs at both ends. The tubes were wrapped in aluminum foil and samples were analyzed for MMT by gas chromatograph-atomic emission detector (GC-AED). Results vary between 0.3 and 11.4 ng m-3, with a mean of 3.9 ng m-3. The highest values obtained in the first study may be due to the analytical techniques used previously, where detection of different Mn compounds other than MMT was possible. Since GC-AED is specific to MMT in the samples, the MMT found in air raises doubt as to the time required for the photodegradation of MMT.

Craft production is one aspect contributing to the general understanding of the Moche site as a Pre-hispanic urban centre between ad100–700 and particularly during phase IV (ad400–700). Spindle whorls are artifacts closely related to the spinning and weaving of cotton. One wonders if these specific tools were produced locally and if they were all made by the artisans working in the only ceramic workshop so far identified on the site. Neutron activation analysis is used to address this question and to explore the possible existence of different workshops specialized in the production of spindle whorls. The only known ceramic workshop was not the primary centre of production, and the identification of a homogeneous group of spindle whorls is used to argue for a distinct source of clay and the possible existence of another workshop.

Neutron activation analysis has been used to characterize 60 metal objects from the Moche site, of which four are associated with the Chimú Period, two with the Early Chimú Period and the others with various Moche IV contexts. Different types of utilitarian and non‐utilitarian objects were analysed to identify the metals present, and to investigate their chemical composition and their eventual source. The results clearly indicate the distinction between Chimú and Moche artefacts and confirm the generalized opinion that arsenic bronze was popular after ad 900. They also indicate that gilding copper objects with gold was already a common practice during the Moche era.

The primary goal of this study is to determine the effects of Mn exposure via inhalation. The bioaccumulation of Mn in different organs and tissues, the alteration of biochemical parameters, and the locomotor activity were assessed. A group of 26 male Sprague-Dawley rats (E) were exposed to 3750 µg/m3 of Mn dust for 6 h/day, 5 days/wk for 13 consecutive weeks and compared to a control group of 12 rats (C) exposed to 4 µg/m3. After exposure, neurological evaluation was carried out for 36 h (a night-day-night cycle) using a computerized autotrack system. Rats were then sacrificed by exsanguination, and Mn content in organs and tissues was determined by neutron activation analysis. Mn concentrations in lung, putamen, and cerebellum were significantly higher in E than in C (0.30 vs. 0.17, 0.89 vs. 0.44, 0.63 vs. 0.48 ppm; p < .01), as well as in the kidney, frontal cortex, and globus pallidus (1.15 vs. 0.96, 0.84 vs. 0.47, 1.28 vs. 0.55 ppm; p < .05). Potassium concentration was significantly lower in E than in C (5.11 vs. 5.79 mmol/L; p < .05), as was alkaline phosphatase (106.9 vs. 129.6 U/L; p < .01). Locomotor activity indicated higher distance covered in the first 12-h period for E (45 383 vs. 36 098 cm; p < .05) and lower resting time in the last 12-h period for E (36 326 vs. 37 393 s; p < .05). This study is the first of several ongoing studies in our laboratory that address health concerns associated with inhalation exposure to different Mn species and to different levels of exposure.

Since 1990, methylcyclopentadienyl manganese tricarbonyl (MMT) has been added to all gasoline in Canada as an antiknock agent. The objective of this study is to determine the percentage of manganese emitted by different types of automobiles and to evaluate the size and chemical characteristics of the Mn-containing particles. Nine vehicles with different mileage and engine capacity were tested using standard procedures for urban and highway driving cycles. One ran on gasoline without MMT and served as a control. The particles were collected using two separate systems: a trapping device consisting of a water tank connected to the tailpipe and a pumping device linked to a cassette containing Teflon filters. Water samples were analyzed by neutron activation to determine the amount of Mn emitted at the tailpipe for each test. Teflon filters were analyzed by electron microscopy to determine the size and the chemical characteristics of the particles. The amount of manganese emitted from the tailpipe varied from 4 to 41% of the manganese consumed, depending on the driving cycle and the vehicle. For the urban cycle, the emission rate was positively correlated with previous mileage. Almost all particles found on teflon filters had a size less than 5 μm. They appeared to be mainly Mn oxides but other elements could be masked by the gold and paladium peaks.

This study aims to assess the atmospheric concentrations of methylcyclopentadienyl manganese tricarbonyl (MMT), respirable manganese (MNR) and total manganese (MnT) in certain specific microenvironments and to provide an estimation of human exposure to MnR. Sampling was carried out in five microenvironments: a gas station, an underground car park, downtown Montreal, near an expressway and near an oil refinery. The samples were collected using Gil-Air portable pumps during three days and were analyzed by instrumental neutron activation analysis (INAA). The mean concentrations of MnR, MnT and MMT were 0.036 microgram m-3, 0.103 microgram m-3 and 0.005 microgram m-3 respectively. The MnR/MnT ratios vary from 25% to 43% (mean 35%) while the MMT/MnT ratios averaged about 5%. Furthermore, the mean concentration of the MnR measured near the expressway (0.053 microgram m-3) is similar to the United States Environmental Protection Agency (U.S. EPA) reference concentration (RfC = 0.05 microgram m-3). The average daily environmental exposure dose to MNR is estimated at 0.010 microgram kg-1 d-1 and its contribution to the multimedia exposure (air, food and water) is low. The overall results show a lack of potential exposure to MMT and substantial concentrations of MnR near an expressway.

The organomanganese compound MMT (methylcyclopentadienyl manganese tricarbonyl), an antiknock additive in unleaded gasoline, has been used in Canada since 1976. Indeed, Canada is the only country where MMT is almost exclusively used. In October 1995, by court decision the Environmental protection Agency (EPA) granted Ethyl's waiver for the use of MMT in the United States. Paradoxically, in 1997 the federal government of Canada adopted a law (C-29) that banned both the interprovincial trade and the importation for commercial purposes of manganese-based substances, including MMT. However, MMT is currently widely used in Canada because of substantial stockpiling, and six Canadian provinces are challenging the law in the courts. Moreover, MMT has been approved for use in Argentina, Australia, Bulgaria, Russia, and conditionally, in New Zealand. It has been suggested by some scientists that combustion of MMT may be a significant source of exposure to inorganic Mn in urban areas. The crucial question is whether Mn contamination from industrial sources combined with the additional contamination that would result from the widespread use of MMT would lead to toxic effects. Our research efforts have attempted to assess the environmental/ecosystem Mn contamination arising from the combustion of MMT in abiotic and biotic systems as well as human exposure. The experimental evidence acquired so far provides useful information on certain environmental consequences of the use of MMT as well as raising a number of questions. Our results gave evidence indicating that roadside air, soils, plants, and animals may be contaminated by Mn. As well, some specific groups of the population could have a higher level of exposure to Mn. Nevertheless, the levels of exposure remain below international guide values. Further studies and further characterization of dose-response relationships are thus needed to provide successful implementation of evidence-based risk-assessment approaches.

Since 1976, methylcyclopentadienyl manganese tricarbonyl (MMT) has been used in Canada as an antiknock agent in gasoline and it completely replaced lead in 1990. The combustion of MMT leads to the formation of Mn oxides, especially Mn3O4. This paper calculates the contribution of Mn from MMT source to the total atmospheric Mn concentration using two dispersion models (CALINE4, ISCLT). The results are compared to CO estimates since CO is often used as a surrogate for Mn human exposure assessment. The study area is located near a major highway (117,585 cars per day) in the city of Montreal. Model estimates were validated using results from two sampling stations located 25 and 250 m from the road centerline. Both models gave similar Mn estimates for distances over 250 m with values ranging from 1 to 3 ng m(-3). These predicted values underestimate by a factor of ten the measured values 250 m from the road. The Mn contribution from MMT may be masked by other sources such as Mn enriched road dust or naturally occurring crustal material. On the other hand, CO estimates and measured values are almost identical. This may be explained by the fact that the mobile source Mn contribution to total atmospheric emissions is less than 20%, whereas for CO it may reach 75%. The total uncertainty in the model predictions was estimated at 50%.

Larval fish were collected from nearshore sites in the west-central basin of Lake Erie from 2000 through 2002. More than 20 species of fish were identified from collections made mid-April through August. Overall fish densities were highest in 2000 and lowest in 2002. Emerald shiners were the most abundant species each year. Gizzard shad, rainbow smelt, white perch, and yellow perch were also abundant. Relative abundance of some species changed with year; rainbow smelt were most numerous in 2000 whereas clupeids were most numerous in 2000 and 2002. Thus far, water temperature and dissolved oxygen appear to follow similar trends among sites and years. However, turbidity changed drastically with year and site. Benthic invertebrate assemblages in soft substrate were primarily composed of oligochaetes, chironomids, nematodes, and clams at all sites throughout the study. Dreissenid mussels were the most abundant taxonomic group of invertebrates over hard substrate. Zooplankton differed with year and site; veligers, rotifers, and nauplii were the most important taxonomic groups. The open-water nearshore zone of the west-central basin of Lake Erie clearly serves as a nursery area for a variety of larval fishes. Future analyses will determine the effects of abiotic and biotic factors on the larval fish community.