Mercury pollution from the past mining of gold and silver in the Americas

The development of the patio amalgamation process into an industrial scale operation in 1554 stimulated the massive production of silver in the New World but left behind an unprecedented quantity of mercury pollution. The annual loss of mercury in the silver mines of Spanish America averaged 612 tonnes/year (range 292-1085 tonnes/year) between 1580 and 1900. The production and importation of mercury into the United States ranged from 268 to 2820 tonnes/year and averaged ~1360 tonnes/year between 1850 and 1900. Approximately 90% of the mercury consumed in the United States during this period was employed in gold and silver extraction. The cumulative losses of mercury to the environment due to the production of precious metals in the Americas totalled ~257 400 tonnes, with 196 000 tonnes dispersed in South and Central America and 61 380 tonnes in the United States. Approximately 60-65% of the mercury lost is believed to have been released to the atmosphere, suggesting that gold and silver mines were a dominant source of atmospheric mercury pollution. Because of its high volatility, any deposited mercury can readily be re-emitted to the atmosphere. The continuing recycling of this large mass of mercury may partly be responsible for the high fluxes of mercury in many parts of North and South America and the high background levels of mercury in the global environment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31497/1/0000419.pd

Mechanistic steps in the photoreduction of mercury in natural waters

Elemental mercury accounts for 10-50% of the dissolved mercury in lakes but plays a vital role in the cycling of this element in lacustrine environments. The view is advanced that a large fraction of the Hg(0) is generated by photochemical reactions in the surface waters. Possible mechanisms for the Hg(0) production are discussed including homogeneous photolysis of dissolved Hg species and photoreduction processes involving organic molecules and inorganic particulates in water.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31336/1/0000246.pd

Geostatistical modeling of the spatial variability of arsenic in groundwater of southeast Michigan

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94929/1/wrcr10188.pd

Acute Toxicity of Thallium to Daphnia magna and Ceriodaphnia dubia

No abstract available.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48000/1/128_2005_Article_760.pd

Cadmium concentrations in recent snow and firn layers in the Canadian arctic

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47997/1/128_2004_Article_BF00195499.pd

Thallium Concentration in Lake Trout from Lake Michigan

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42357/1/128-67-6-921_10670921.pd

Historical trends of airborne trace metals in Detroit from 1971 to 1992

Ambient concentrations of particulate Fe, Zn, Ph, Ni, Cr, Cd and Hg were measured at nine sites located in the metropolitan area of Detroit from 1971 to 1992. The ambient concentrations of all the trace metals were found to be generally higher at industrial and commercial sites. The concentrations show significant variations between residential and commercial areas and between residential and industrial areas; however, no significant variation was found between the industrial and commercial settings. The spatial variation of trace metal levels within the urban area was influenced by the frequency distribution of the wind direction as well as type and location of emission sources. The ambient concentrations of the trace metals during the decade of 1971–1981 declined by 37–88%. In the 1980s many of the trace metals reversed this trend with the exception of Fe and Pb which continued to decline at annual rates of 2% and 9.8%, respectively. The sharp decrease in Pb concentrations during the 1980s, reflected the significant reduction of Pb content in gasoline from 0.28 g/liter in the 1982 to 0.026 g/liter in the 1989. The ambient concentrations of Zn, Ni, Cr, Cd and Hg showed an upward trend during the 1980s with an annual rate in the range of 0.6% to 10.6%. The long-term trends of selected U.S. market parameters, analyzed as potential long-term indicators of emission sources activityies, were consistent with the changes of ambient concentrations, the correlation coefficient being in the range of 0.58 to 0.84 for most of the trace metals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43917/1/11270_2004_Article_BF00157419.pd

Spatial clustering of emergency department visits by asthmatic children in an urban area: south-western Detroit, Michigan

Objective This ecological study evaluates the correlation of asthma clusters with outdoor air pollution, race, and household income in South-western Detroit, Michigan. Design To attain this objective (1) a geographic information aystem (GIS) is utilized to evaluate the relationships between rates of emergency department (ED) admissions for asthma, race, and socio-economic status at the neighborhood block group level of analysis; (2) cluster statistical analyses are performed using Geomed software; and (3) the asthma risk from industrial air pollution was evaluated with windrose data and Screen3 air pollution model. Sample Data from five major hospitals with ED admissions of asthma patients (code 493), aged 0–15 years, are used to select a region of analysis with good geographical representation based on the catchment areas of hospitals in the study. A total of 2067 of the reported cases between 1 January 1993 and 30 June 1998, are successfully geocoded to a map, generating a no-match rate of 8.4%. Data on racial characteristics, population density, and household income levels are obtained from neighborhood block groups in the 1990 census report. Locations of major polluting industries within the study area are obtained from the Toxics Release Inventory. Results Spatial analysis identified a local asthma cluster roughly 2 km east (the predominant downwind direction) of the second and third largest air polluters (in terms of tonnage) in Wayne County. Evaluation of the industrial pollution with a focused cluster test, Screen3 air pollution model, and windrose figures, displayed weak association between ED asthma admissions and estimated levels of outdoor air pollution from these two facilities. The neighborhood block groups in the local asthma cluster are more closely correlated with high proportions of African Americans and low median household income. Implications for practice This study illustrates the strengths and weaknesses of GIS in the public health arena. It highlights the difficulty of disentangling the effects of exposure to outdoor air pollutants and socio-economic factors on ED asthmatics (reflecting asthma severity) among an urban population. This study also illustrates the need for population-based, as opposed to hospital-based, asthma data, and the need for block-groups, as opposed to zip codes, as a spatial unit of analysis in the evaluation and analysis of asthma-related risk factors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73994/1/j.1467-0658.2001.00143.x.pd