Disaster issues and management in farm and urban crop production.

Abstract

Disasters fall mainly into two categories: natural and man-made. The purpose of this commentary is to review a few potential health hazards that occur due to human activities, specifically the contamination of soil where food is produced. Soil quality may change as the unintended consequence of a host of man-made and environmental mediations. These include the presence of construction rubble (particularly paint residues, plumbing fixtures, broken glass, caulking, and plastics), various batteries, remnants of leaded gasoline runoff, garbage (e.g. food wrappers and drink containers), and contamination from the surrounding water and air.1 In addition to their potential to alter the chemical composition of the soil, these materials can obstruct its water-holding capacity, affect the development of plant roots, and decrease the proliferation of essential soil organisms.2HEAVY METALS - AN IMPORTANT PUBLIC HEALTH PROBLEMThe occurrence of heavy metals in soils has been intensified during the last few decades by industrial and agricultural development (storage of industrial and municipal wastes, burning of fuels, application of pesticides and fertilizers, mining and wastewater treatments, functioning of non-ferrous-metalproducing smelters, etc.).3 In addition, some natural disasters including hurricanes and floods can spread fecal coliform and pathogenic viruses along with toxic metals from toxic waste sites.4 However, these issues are underreported.The contamination of the environment is serious and critical and can pose devastating health consequences. This is a topic of great interest for public health. A large number of toxic metals and metalloids, such as copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As), among many others, have accumulated in soils, reaching toxic values.3 Unfortunately, much contaminated land is in use for crop production all over the world. In Western Europe alone, more than 1.4 million sites are polluted with heavy metals and metalloids.5 The World Health Organization (WHO) describes groundwater As contamination as 'the largest mass poisoning of a population in history', having impacted over 500 million people's lives in 70 countries on six continents.6Heavy metals could negatively affect human health through consumption of plants, particularly when the produce is grown in contaminated soil, or irrigated with polluted water. There is increasing evidence that the soil contaminants can transfer to the plants, become bioavailable in foods, and as such, can cause consequent health risks.7 For example, in Titagarh, India, water contaminated with high concentrations of Pb, nickel (Ni), and Cu has been used for irrigation of vegetables and higher than recommended levels of Cd have been found in the soil. The mean levels of Pb, Zn, Cd, chromium (Cr), and Ni in vegetables growing in this soil were found to be above the Indian safety limits.8The presence of Pb in crop systems has been of particular concern for the potential for a public health disaster.9 The presence of Pb in the soil-rice system in China has been reported, which could be catastrophic for the population that relies on this food staple.10 This condition can pose multiple health problems for at-risk population groups such as children, pregnant women, and older adults. For example, children are particularly susceptible to Pb-exposure due to high gastrointestinal absorption.11 A neurotoxic effect of Pb at lower levels of exposure has been reported.12 Furthermore, an As concentration range from 10 to 2,000 µg/L has been linked with several diseases, including spontaneous pregnancy loss, respiratory complications, diabetes, immunological problems, and skin cancer.13 The Hazard Index (HI) has been widely used in health-risk assessment studies in contaminated areas to establish the toxic and the non-carcinogenic toxicity of substances. A HI less than one is considered to infer no significant risk of non-carcinogenic effects. …