Mercury and Methylmercury Toxicology and Risk Assessment

Mercury is a global pollutant that affects the health of both humans and ecosystems. This Special Issue collects three review papers and six research articles that report on the latest findings on the mechanisms of mercury toxicology and its impacts on environmental health. This collection of papers provides useful, new information on the mechanisms of mercury toxicity and methods of improving the risk assessment of mercury exposure

Aboriginal Food Security in Northern Canada: An Assessment of the State of Knowledge

As the world’s population increases, as global markets become more interconnected, and as the effects of climate change become clearer, the issue of food insecurity is gaining traction at local, national, and international levels. The recent global economic crisis and increased food prices have drawn attention to the urgent situation of the world’s 870 million chronically undernourished people who face the number one worldwide risk to health: hunger and malnutrition. Although about 75% of the world’s undernourished people live in low-income, rural regions of developing countries, hunger is also an issue in Canada. In 2011, 1.6 million Canadian households, or slightly more than 12%, experienced some level of food insecurity. About one in eight households are affected, including 3.9 million individuals. Of these, 1.1 million are children. Food insecurity presents a particularly serious and growing challenge in Canada’s northern and remote Aboriginal communities (see Figure 1). Evidence from a variety of sources concludes that food insecurity among northern Aboriginal peoples is a problem that requires urgent attention to address and mitigate the serious impacts it has on health and well-being. Results from the 2007–2008 International Polar Year Inuit Health Survey indicate that Nunavut has the highest documented rate of food insecurity for any Indigenous population living in a developed country. According to estimates from the 2011 Canadian Community Health Survey (CCHS), off-reserve Aboriginal households across Canada experience food insecurity at a rate that is more than double that of all Canadian households (27%). Recent data indicate that Canadian households with children have a higher prevalence of food insecurity than households without children, and preliminary evidence indicates that more women than men are affected

Effects of Arsenic, Iron and Fertilizers in Soil on Rice in Cambodia

Background. In parts of Cambodia, irrigation with groundwater results in arsenic accumulation in soils and rice, leading to health concerns associated with rice consumption. A high concentration of iron in groundwater can precipitate arsenic and reduce its bioavailability, however high concentrations of arsenic and iron can also reduce rice production. Furthermore, concerns have been raised about chemical contamination from inorganic fertilizers used to grow rice. The relationship between soil geochemistry and arsenic concentrations in rice is not yet fully understood. Objectives. The primary objective of this project was to investigate the relationship between arsenic concentrations in irrigation water, soil and rice collected from different sites in Cambodia. A secondary objective was to explore arsenic and phosphorus levels in fertilizer samples obtained from the study area in Cambodia. Methods. The present study collected 61 well water samples, 105 rice samples, 70 soil samples, 11 inorganic fertilizer samples and conducted interviews with 44 families along the Mekong River in Cambodia. Analyses for metals, total arsenic, and arsenic species in the water and rice were conducted in Canada by inductively coupled plasma mass spectrometry. Analyses for metals, total arsenic and phosphorus in soils and inorganic fertilizers were conducted in Cambodia and Singapore by X-ray fluorescence. Results. The concentration of arsenic in rice paddy soils was highly variable and as much as 20 times higher near the irrigation wells than in more distal areas of the paddy. Two farmers in Preak Russey had integrated soil samples with arsenic levels above the concentration associated with toxicity to rice in Taiwan (40 mg/kg) and above the Dutch concentration requiring intervention or remediation (55 mg/kg). The highest total arsenic measured in soil was 95 mg/kg. In Preak Russey, the loading of arsenic from irrigation water was 3710 times greater than the loading of arsenic from inorganic fertilizers. Half of the commercial inorganic fertilizers had less than 50% of the labelled content of phosphorus. Conclusions. Emphasis should be placed on improving the management of irrigation water, not on inactivation of arsenic in soil. The high levels of iron in groundwater mitigate arsenic toxicity, but the accumulation of iron could later result in lower rice productivity. Irrigation of rice with groundwater is not likely sustainable. To improve rice productivity, the content of phosphorus in local inorganic fertilizers must be improved to world standards. X-ray fluorescence analysis can quickly identify poor quality fertilizers. Informed Consent. Obtained Competing Interests. The authors declare no competing financial interest

Groundwater Irrigation and Arsenic Speciation in Rice in Cambodia

Background. Arsenic bioaccumulation in rice is a global concern affecting food security and public health. Objective. The present study examined arsenic species in rice in Cambodia to characterize health risks with rice consumption and to clarify uncertainties with Codex guidelines. Methods. The present study collected 61 well water samples, 105 rice samples, 70 soil samples, and conducted interviews with 44 families in Preak Russey near the Bassac River and Kandal Province along the Mekong River in Cambodia. Analyses of metals, total arsenic and arsenic species were conducted in laboratories in Canada, Cambodia and Singapore. Results. Unlike in Bangladesh, rice with the highest total arsenic concentrations in Cambodia contains mostly organic arsenic, dimethylarsinic acid (DMA), which is unregulated and much less toxic than inorganic arsenic. The present study found that storing surface runoff in ditches prior to irrigation can significantly reduce the arsenic concentration in rice. It is possible to remove > 95% of arsenic from groundwater prior to irrigation with natural reactions. Conclusions. The provision of high quality drinking water in 2015 to Preak Russey removed about 95% of the dietary inorganic arsenic exposure. The extremes in arsenic toxicity that are still obvious in these farmers should become less common. Rice from the site with the highest documented levels of arsenic in soils and water in Cambodia passes current Codex guidelines for arsenic. Informed Consent. Obtained Competing Interests. The authors declare no competing financial interests

Aboriginal Food Security in Northern Canada: An Assessment of the State of Knowledge

As the world’s population increases, as global markets become more interconnected, and as the effects of climate change become clearer, the issue of food insecurity is gaining traction at local, national, and international levels. The recent global economic crisis and increased food prices have drawn attention to the urgent situation of the world’s 870 million chronically undernourished people who face the number one worldwide risk to health: hunger and malnutrition. Although about 75% of the world’s undernourished people live in low-income, rural regions of developing countries, hunger is also an issue in Canada. In 2011, 1.6 million Canadian households, or slightly more than 12%, experienced some level of food insecurity. About one in eight households are affected, including 3.9 million individuals. Of these, 1.1 million are children. Food insecurity presents a particularly serious and growing challenge in Canada’s northern and remote Aboriginal communities (see Figure 1). Evidence from a variety of sources concludes that food insecurity among northern Aboriginal peoples is a problem that requires urgent attention to address and mitigate the serious impacts it has on health and well-being. Results from the 2007–2008 International Polar Year Inuit Health Survey indicate that Nunavut has the highest documented rate of food insecurity for any Indigenous population living in a developed country. According to estimates from the 2011 Canadian Community Health Survey (CCHS), off-reserve Aboriginal households across Canada experience food insecurity at a rate that is more than double that of all Canadian households (27%). Recent data indicate that Canadian households with children have a higher prevalence of food insecurity than households without children, and preliminary evidence indicates that more women than men are affected

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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