Monday, November 29, 2010

Increased lung cancer risks are similar whether arsenic is ingested or inhaled.

Journal of Exposure Science and Environmental Epidemiology 2009, 19: 343–348 
Smith AH, Ercumen A, Yuan Y, Steinmaus CM. 
Arsenic Health Effects Research Program,School of Public Health, University of California, Berkeley, California, USA, and the Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, California, USA. 
Abstract - In 1980, the International Agency for Research on Cancer (IARC) determined there was sufficient evidence to support that inorganic arsenic was a human lung carcinogen based on studies involving exposure through inhalation. In 2004, IARC listed arsenic in drinking water as a cause of lung cancer, making arsenic the first substance established to cause human cancer through two unrelated pathways of exposure. It may initially seem counterintuitive that arsenic in drinking water would cause human lung cancer, and even if it did, one might expect risks to be orders of magnitude lower than those from direct inhalation into the lungs. In this paper, we consider lung cancer dose–response relationships for inhalation and ingestion of arsenic by focusing on two key studies, a cohort mortality study in the United States involving Tacoma smelter workers inhaling arsenic, and a lung cancer case–control study involving ingestion of arsenic in drinking water in northern Chile. When exposure was assessed based on the absorbed dose identified by concentrations of arsenic in urine, there was very little difference in the dose–response findings for lung cancer relative risks between inhalation and ingestion. The lung cancer mortality rate ratio estimate was 8.0 (95% CI 3.2–16.5, P < 0.001) for an average urine concentration of 1179 microg/l after inhalation, and the odds ratio estimate of the lung cancer incidence rate ratio was 7.1 (95% CI 3.4–14.8, P < 0.001) for an estimated average urine concentration of 825 microg/l following ingestion. The slopes of the linear dose-response relationships between excess relative risk (RR-1) for lung cancer and urinary arsenic concentration were similar for the two routes of exposure. We conclude that lung cancer risks probably depend on absorbed dose, and not on whether inorganic arsenic is ingested or inhaled.

Sunday, November 21, 2010

Letter to Professor Alastair Summerlee

Letter to Professor Alastair Summerlee, President and Vice-Chancellor of the University of Guelph, Ontario, Canada
November 21, 2010
Professor Alastair Summerlee
President and Vice-Chancellor of the University of Guelph
Mr. President,
Having read the announcement that the University of Guelph accepted a $1-million gift from Kinross Gold Corporation [1], I feel obliged to inform you that this gift has been made possible thanks to questionable Kinross’ mining activities, especially at my home town Paracatu, state of Minas Gerais, Brazil.

Friday, November 19, 2010

MIMER notes November 19, 2010: Arsenic in urine

Urinary arsenic determined in a large US survey

Urinary concentrations of different forms of arsenic have been determined for the United States populations from the National Health and Nutritional Examination Survey (NHANES). The results have been published by the Centers for Disease Control (CDC) in the CDC Fourth National Report on Human Exposure to Environmental Chemicals ("the fourth report", published 2010). For the first time, the fourth report provides comprehensive information about arsenic presence. Urinary total arsenic varied from 5.66 mcg/l (equivalent to 6.58 mcg/g of creatinine) in children to 164 mcg/l (98.8 mcg/g of creatinine) in adults. Some children presented with total urinary arsenic concentration of 178 mcg/l (188 mcg/g creatinine). Arsenic has been associated with all top 10 causes of death worldwide, including cardiovascular disease, cerebrovascular diseases, diabetes, dementias and cancer. The ranges for arsenic are provided so the clinician can compare a patient's readings against national percentiles. The data will help the clinician identify current exposures and monitor the effectiveness of treatments.
Source: [accessed 19 November 19, 2010]

Sunday, November 14, 2010

Spontaneous pregnancy loss in humans and exposure to arsenic

Int J Hyg Environ Health. 2010 Oct 1. [Epub ahead of print]
Spontaneous pregnancy loss in humans and exposure to arsenic in drinking water.
Bloom MS, Fitzgerald EF, Kim K, Neamtiu I, Gurzau ES.
Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Rensselaer, NY, United States; Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, State University of New York, Rensselaer, NY, United States.

Maternal exposure to high concentrations of inorganic arsenic (iAs) in naturally contaminated drinking groundwater sources has been associated with an increased risk for the spontaneous loss of clinically recognized pregnancies in several epidemiologic studies. Whereas a large worldwide population depends on drinking groundwater sources with high levels of iAs contamination, in quantities exceeding 10 parts per billion (ppb), an even larger population is likely to be exposed to mild-moderate drinking groundwater iAs contamination, in quantities <10ppb. Only a single epidemiologic study to date has considered spontaneous pregnancy loss in association with consumption of drinking water with mild-moderate iAs contamination; the vast majority of published studies of spontaneous loss addressed populations with substantial exposure. The aim of this review is to evaluate the published literature to assess the plausibility for a causal association between exposure to iAs-contaminated drinking water and the spontaneous loss of clinically recognized pregnancy. In spite of numerous methodologic limitations resulting from circumstance or design, a consistent pattern of increased risk for loss is suggested by the epidemiologic literature. Moreover, these study results are corroborated by a large number of experimental studies, albeit usually conducted at concentrations exceeding that to which humans are exposed via contaminated drinking water. In this review, we discuss sources of human iAs exposure, highlight several experimental studies pertinent to a possible causal link between iAs and spontaneous pregnancy loss in humans, and provide a critical review of published epidemiologic studies of pregnancy loss and drinking water iAs exposures, and their limitations. Based on a review of the published literature, we recommend the future conduct of a two-stage comprehensive prospective study of low-moderate iAs drinking water exposure and spontaneous pregnancy loss.

Behaviour of arsenic in forested catchments

Environ Pollut. 2010 Oct 5. [Epub ahead of print]
Behaviour of arsenic in forested catchments following a high-pollution period.
Novak M, Erbanova L, Fottova D, Cudlin P, Kubena A.
Department of Geochemistry, Czech Geological Survey, Geologicka 6, 152 00 Prague 5, Czech Republic.

Due to high availability of adsorption sites, forested catchments could be net sinks for pollutant arsenic both during the period of increasing and decreasing pollution. We tested this hypothesis along a north-south pollution gradient in spruce die-back affected areas of Central Europe. For two water years (2007-2008), we monitored As fluxes via spruce-canopy throughfall, open-area precipitation, and runoff in four headwater catchments (Czech Republic). Since 1980, atmospheric As inputs decreased 26 times in the north, and 13 times in the south. Arsenic export by runoff was similar to atmospheric inputs at three sites, resulting in a near-zero As mass balance. One site exhibited a net export of As (2.2 g ha(-1) yr(-1)). In contrast, the preceding period (1995-2006) showed much higher As fluxes, and higher As export. Czech catchments do not serve as net sinks of atmospheric As. A considerable proportion of old industrial arsenic is flushed out of the soil.

Chronic arsenicosis in cattle in West Bengal, India

Sci Total Environ. 2010 Nov 6. [Epub ahead of print]
Datta BK, Mishra A, Singh A, Sar TK, Sarkar S, Bhatacharya A, Chakraborty AK, Mandal TK.
Department of Veterinary Pharmacology and Toxicology, West Bengal University of Animal and Fishery Sciences, 37, K.B. Sarani, Kolkata 700037, West Bengal, India.

Thirty Milch cattle were selected randomly from a village of Nadia district of West Bengal, India containing high arsenic in water and soil samples. Milk, feces and hair samples were collected to analyze arsenic status in animals. Water and straw samples were also estimated for arsenic. Milk products prepared from milk of cattle rearing in arsenic prone village were also collected to quantify total arsenic and speciation of arsenic in milk and feces samples were also carried out. It was observed that high amount of arsenic was present in milk, feces, hair of cattle and water and straw samples in arsenic prone village. Milk product also contained significant amount of arsenic than that of milk product of control village. Speciation study revealed arsenite fraction was mainly eliminated through milk, whereas organoarsenic species were mainly excreted through feces.

Migration of arsenic in groundwater from West Bengal

Water Res. 2010 Jul;44(14):4171-85. Epub 2010 May 21.
Migration of As, and (3)H/(3)He ages, in groundwater from West Bengal: Implications for monitoring.
McArthur JM, Banerjee DM, Sengupta S, Ravenscroft P, Klump S, Sarkar A, Disch B, Kipfer R.
Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.

From 2002 to 2010 inclusive we monitored concentrations of arsenic (As) and major ions (Ca, Mg, Sr, Na, K, Fe, Mn, Cl, and SO(4)) in groundwater from 14 domestic wells and three piezometer nests in a shallow aquifer (<60 m depth), and 3 wells in a deep aquifer (>70 m depth), in southern West Bengal, India. In the deep aquifer, concentrations of As did not change over time despite increases in the concentration of Fe in two wells. The shallow aquifer occurs in two sedimentological settings: palaeo-channel and palaeo-interfluve. At the top of the shallow aquifer of the palaeo-channel, decreases in all constituent concentrations with time, and an (3)H/(3)He age of 1.4 years, proves that the aquifer is beginning to be flushed of pollutants. In As-polluted groundwater (>50 microg/L As) tapped from deeper grey sands of the shallow, palaeo-channel, aquifer, concentrations of As were mostly stable over time, but both increases and decreases occurred with time in response to downward migration of the chemically-stratified water column. In groundwater tapped from Pleistocene brown sands, the concentration of As remained either low and stable (<2 microg/L As), or increased at rates up to 34 microg/L per year. The increases were caused by the flow of As-rich groundwater either downward into brown sand at the base of palaeo-channels, or laterally into a confined, unpolluted, palaeo-interfluvial, aquifer of brown sand that lies regionally beneath a palaeosol. Under the present pumping regime, the prognosis for As-pollution in the shallow aquifer is complex. Wells in brown sand may become polluted over timescales of as little as 2 years, whilst some wells tapping As-polluted groundwater from grey sand will become fit for potable use (<50 microg/L) within a few decades. The evidence of flushing, and of declining As in some of the groundwater from palaeo-channels, which are conduits for recharge of the confined, As-free, palaeo-interfluve aquifer, and probably also the deeper aquifer, offers hopes that the spread of As-pollution will be limited.

Arsenic round the world: a review.

Arsenic round the world: a review.
Talanta. 2002 Aug 16;58(1):201-35.
Mandal BK, Suzuki KT.
Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 263-8522, Japan.

This review deals with environmental origin, occurrence, episodes, and impact on human health of arsenic. Arsenic, a metalloid occurs naturally, being the 20th most abundant element in the earth's crust, and is a component of more than 245 minerals. These are mostly ores containing sulfide, along with copper, nickel, lead, cobalt, or other metals. Arsenic and its compounds are mobile in the environment. Weathering of rocks converts arsenic sulfides to arsenic trioxide, which enters the arsenic cycle as dust or by dissolution in rain, rivers, or groundwater. So, groundwater contamination by arsenic is a serious threat to mankind all over the world. It can also enter food chain causing wide spread distribution throughout the plant and animal kingdoms. However, fish, fruits, and vegetables primarily contain organic arsenic, less than 10% of the arsenic in these foods exists in the inorganic form, although the arsenic content of many foods (i.e. milk and dairy products, beef and pork, poultry, and cereals) is mainly inorganic, typically 65-75%. A few recent studies report 85-95% inorganic arsenic in rice and vegetables, which suggest more studies for standardisation. Humans are exposed to this toxic arsenic primarily from air, food, and water. Thousands and thousands of people are suffering from the toxic effects of arsenicals in many countries all over the world due to natural groundwater contamination as well as industrial effluent and drainage problems. Arsenic, being a normal component of human body is transported by the blood to different organs in the body, mainly in the form of MMA after ingestion. It causes a variety of adverse health effects to humans after acute and chronic exposures such as dermal changes (pigmentation, hyperkeratoses, and ulceration), respiratory, pulmonary, cardiovascular, gastrointestinal, hematological, hepatic, renal, neurological, developmental, reproductive, immunologic, genotoxic, mutagenetic, and carcinogenic effects. Key research studies are needed for improving arsenic risk assessment at low exposure levels urgently among all the arsenic research groups.