Standards for levels of lead in soil and dust around the world.

Lead poisoning is a serious environmental health problem in every country in the world. Exposure to lead results in neurocognitive and behavioral changes, has adverse effects on the immune system, causes anemia, hypertension and perturbs other organ systems. The effects of lead poisoning are most critical for children because their bodies are growing and developing, and particularly because agents that reduce cognitive function and attention span as well as promote disruptive behavior will have life-long consequences. Lead exposure, especially to children, is a major health disparity issue. If the next generation starts with reduced cognitive ability, there will be significant barriers for development of skills and country-wide development. While there are many sources of exposure to lead, the commonest source is lead in soil and dust. Since lead is an element, it does not go away and past releases of lead into the environment remain as soil and dust contamination. This is an especially important route of exposure to children because children regularly play in soil and are exposed via hand-to-mouth activity. In addition to indoor sources of lead, contaminated soil is tracked on shoes or feet and blown by air currents into homes, accumulating in household dust which is a major source of exposure for both children and adults. The purpose of this review is to determine standards presumed to be health protective for lead and dust in different countries. We find that many countries have no standards for lead in soil and dust and rely on standards set by the World Health Organization or the US Environmental Protection Agency, and these standards may or may not be enforced. There is considerable variation in standards set by other countries.

Fine particulate matter and its chemical constituents' levels: A troubling environmental and human health situation in Karachi, Pakistan.

Like many urban centers in developing countries, the effect of air pollution in Karachi is understudied. The goal of this study was to determine the chemical characterization, temporal and seasonal variability, sources, and health impacts of fine particulate matter (PM2.5) in Karachi, Pakistan. Daily samples of PM2.5 were collected using a low-volume air sampler at two different sites (Makro and Karachi University) over the four seasons between October 2009 and August 2010. Samples were analyzed for black carbon (BC), trace metals, and water-soluble ions. Results showed that the annual average concentrations of PM2.5 at Makro and Karachi University were 114 ± 115 and 71.7 ± 56.4 µg m-3, respectively, about 22.8 and 14.3-fold higher than the World Health Organization annual guideline of 5 µg m-3. BC concentrations were 3.39 ± 1.97 and 2.70 ± 2.06 µg m-3, respectively. The concentrations of PM2.5, BC, trace metals, and ions at the two sites showed clear seasonal trends, with higher concentrations in winter and lower concentrations in summer. The trace metals and ionic species with the highest concentrations were Pb, S, Zn, Ca, Si, Cl, Fe, and SO42-. The air quality index in the fall and winter at both sites was about 68 %, which is "unhealthy" for the general population. Positive Matrix Factorization revealed the overall contribution to PM2.5 at the Makro site came from three major sources - industrial emissions (13.3 %), vehicular emissions (59.1 %), and oil combustion (23.3 %). The estimates of expected number of deaths due to short-term exposure to PM2.5 were high in the fall and winter at both sites, with an annual mean estimate of 3592 expected number of deaths at the Makro site. Attention should be paid to the reduction of inorganic pollutants from industrial facilities, vehicular traffic, and fossil fuel combustion, due to their extremely high contribution to PM2.5 mass and health risks.

State of gaseous air pollutants and resulting health effects in Karachi, Pakistan.

Karachi, Pakistan, is a priority site for air pollution research due to high emissions of air pollutants from vehicular traffic, industrial activities, and biomass burning, as well as rapid growth in population. The objectives of this study were to investigate the levels of gaseous pollutants (NO, NO2, O3, HNO3, and SO2) in Karachi, to determine temporal and seasonal variations, to compare Karachi's air quality with other urban centers, to identify relationships with meteorological conditions, to identify source characterization, and to perform a backward-in-time trajectory analysis and a health impact assessment. Daily samples of gaseous pollutants were collected for six consecutive weeks in each of the four seasons for a year. Daily maximum concentrations of NO (90 parts per billion by volume (ppbv)), NO2 (28.1 ppbv), O3 (57.8 ppbv), and SO2 (331 ppbv) were recorded in fall, while HNO3 (9129 parts per trillion by volume (pptv)) was recorded in spring. Seasonal average concentrations were high in winter for NO (9.47 ± 7.82 ppbv), NO2 (4.84 ± 3.35 ppbv), and O3 (8.92 ± 7.65 ppbv), while HNO3 (629 ± 1316 pptv) and SO2 (20.2 ± 39.4 ppbv) were high in spring and fall, respectively. The observed SO2 seasonal average concentration in fall (20.2 ± 39.4) was 5 times higher than that in summer (3.97 ± 2.77) with the fall 24-h average (120 ppbv) exceeding the WHO daily guideline (7.64 ppbv) by a factor of about 15.7. A health impact assessment estimated an increase of 1200 and 569 deaths due to short-term exposure to SO2 in fall and spring, respectively. Chronic daily intake estimated risk per 1000 was 0.99, 0.47, 0.45, and 0.26 for SO2 in fall, NO in winter, O3 in winter, and NO2 in spring, respectively. This study confirms the effect of poor urban air quality on public health and demonstrated the influence of photochemical reactions as well as unfavorable meteorological conditions on the formation of secondary pollutants.

E-Waste in Africa: A Serious Threat to the Health of Children.

Waste electronic and electrical equipment (e-waste) consists of used and discarded electrical and electronic items ranging from refrigerators to cell phones and printed circuit boards. It is frequently moved from developed countries to developing countries where it is dismantled for valuable metals in informal settings, resulting in significant human exposure to toxic substances. E-waste is a major concern in Africa, with large sites in Ghana and Nigeria where imported e-waste is dismantled under unsafe conditions. However, as in many developing countries, used electronic and electrical devices are imported in large quantities because they are in great demand and are less expensive than new ones. Many of these used products are irreparable and are discarded with other solid waste to local landfills. These items are then often scavenged for the purpose of extracting valuable metals by heating and burning, incubating in acids and other methods. These activities pose significant health risks to workers and residents in communities near recycling sites. E-waste burning and dismantling activities are frequently undertaken at e-waste sites, often in or near homes. As a result, children and people living in the surrounding areas are exposed, even if they are not directly involved in the recycling. While toxic substances are dangerous to individuals at any age, children are more vulnerable as they are going through important developmental processes, and some adverse health impacts may have long-term impacts. We review the e-waste situation in Africa with a focus on threats to children's health.