Mercury exposure in the work place and human health: dental amalgam use in dentistry at dental teaching institutions and private dental clinics in selected cities of Pakistan.

During the past two decades, mercury has come under increasing scrutiny with regard to its safety both in the general population and in occupationally exposed groups. It's a growing issue of global concern because of its adverse environmental and health impacts. Very few investigations on mercury amalgam use in the dentistry sector have been carried out in South Asia and there is little data reported on mercury contamination of indoor/outdoor air at dental sites. According to an earlier SDPI study, reported in 2013, alarmingly high mercury levels were observed in air (indoor as well as outdoor) at 11 of the 34 visited dental sites (17 dental teaching institutions, 7 general hospitals & 10 dental clinics) in five main cities of Pakistan. 88% of the sites indicated indoor mercury levels in air above the USA EPA reference level of 300 ng/m3. According to our study, carried out at 38 dental teaching institutions in 12 main cities (in Khyber Pakhtunkhwa, Punjab and Sindh provinces) of Pakistan, respondents were of the opinion that the currently offered BDS curriculum does not effectively guide outgoing dental professionals and does not provide them adequate knowledge and training about mercury/mercury amalgam and other mercury related human health and mercury waste issues. 90% of respondents supported the review and revision of the present dental curriculum offered at dental teaching institutions in the country, at the earliest. A study has also been conducted to assess the status of mercury amalgam use in private dental clinics in Gilgit, Hunza, Peshawar, Rawalpindi and Islamabad. More than 90 private dental clinics were visited and dental professionals/private clinics in-charge were interviewed during June-July, 2015. The focus areas of the study were Hg amalgam toxicity, its waste management practices and safety measures practiced among the dental practitioners. In the light of the findings described and discussed in this brief report, to safeguard public health and for the protection of environment, it is strongly recommended that since mercury amalgam use cannot be banned immediately in the country, its use may be regularized and allowed subject to use of "Amalgam Separators," "Capsulated Mercury" and "Mechanized Mixing," use of mercury amalgam be banned for children (below 12 years age) and pregnant women. The curriculum currently being taught at medical and dental colleges in the country be reviewed and revised, to ensure adequate training towards minimizing mercury exposure.

Mercury poisoning dentistry: high-level indoor air mercury contamination at selected dental sites.

Mercury (Hg), also known as quick silver, is an essential constituent of dental amalgam. It is a toxic substance of global concern. Children are more at risk from mercury poisoning which affects their neurological development and brain. In the past, a number of studies at dental sites in many countries have been carried out and reported. The present report briefly describes and discusses our recent investigations carried out at 34 dental sites (teaching institutions, hospitals and private clinics) in Pakistan. It is evident from the data that at many sites the indoor mercury vapor levels exceed far above the permissible limit recommended for safe physical and mental health. At these sites, public in general and the medical, paramedical staff and vulnerable population in particular, are at most serious risk to health resulting from exposure to toxic and hazardous mercury. To minimize such risk, some of the recommendations are, best in-house environmental practices for occupational health and safety, mercury contaminated waste reduction at source, mercury specific legislation and ratification of Minamata convention on mercury by Pakistan and other world governments at the earliest time possible.

Former DDT factory in Pakistan revisited for remediation: severe DDT concentrations in soils and plants from within the area.

A factory in Amman Garh near Nowshera, Khyber Pakhtunkhwa, Pakistan, produced dichlorodiphenyltrichloroethane (DDT) from 1963-1994. Consequently, earlier papers reported a soil contamination in the per mille range inside the former factory wall (88 m × 106 m) and up to 10 mg/kg of DDT in the surroundings in 2005-2007. The site within the factory wall was remonitored systematically in 2011 to complement the earlier data as a prerequisite for remediation, to put them in exposure context in a population developing area, and to suggest and evaluate the optimal remediation technique for the site. The contamination was drastically higher than the earlier published data, and the sum of DDT and its metabolites (ΣDDT) was up to 65% in the soil. Grasses, shrubs, and trees growing in this severely contaminated site had 50-450 mg/kgdw of ΣDDT. Thus, people living nearby and husbandry as well as wild animals are heavily exposed to DDT. The semiarid climate favors wind drift and deposition of the pollutant. Additionally, DDT from products of herbivore animals feeding on the contaminated plants will enter the food web. To overcome the exposure and distribution of the DDT, the site within the factory wall was capped with 1.5 m of soil. This remediation technique represents the easiest and least expensive solution. Nevertheless, DDT can still evaporate or leach, and groundwater can rise in this flood-prone area and thereby become contaminated, especially because a binding layer is missing.

Hazardous waste in the Asian Pacific region.

The production and disposal of hazardous waste remains a substantial problem in the Asian Pacific region. Remediation of waste disposal sites, including landfill sites, is attracting considerable research attention within the region. A recognition of the need for community engagement in this process is also growing. This article reviews the work presented in the Hazardous Waste sessions at the Pacific Basin Consortium for Environment and Health held in November 2009 in Perth.

POPs hot spot.

Like other chemicals of the persistent organic pollutant (POP) group, dichlorodiphenyltrichloroethane (DDT), a pesticide, is also persistent in nature and does not readily degrade in the environment by biological, physical, or chemical processes. In view of the known toxicity, accumulative, persistent characteristics, and adverse environmental and health impacts of DDT, an extensive survey of the soil was undertaken in and around a demolished DDT factory at Nowshera, NWFP, to examine DDT levels of the contaminated soil. For the present study, 81 soil samples were collected within a half-kilometer distance from the old gate of the factory and at different depths in eight different directions. Analytical data indicated that 90.91% of the soil samples studied were contaminated with DDT, with 66.6% of the samples indicating residual DDT levels higher than DDT minimum risk level (MRL) in soil (0.05 microg/g). Soil in the southeast direction appeared to be the most contaminated (average 6.70 +/- 1.25 microg/g), showing 5.19 microg/g residual DDT in a soil sample collected as far away as 520 m from the factory. Soil in the south direction also appeared highly contaminated, with an average DDT residual level of 7.16 +/- 1.70 microg/g between 65 and 390 m from the factory. For soil between the surface and a depth of 0.60 m, the highest residual DDT level (5.78 +/- 3.94 microg/g) was observed in samples from the northwest direction, followed by samples from the west direction (4.88 +/- 3.80 microg/g).

Meeting report: threats to human health and environmental sustainability in the pacific basin.

The coastal zone of the Pacific Rim is home for about one-third of the world's population. Disproportionate growth of Far Eastern economies has produced a disproportionate share of related environmental difficulties. As the region searches for acceptable compromises between growth and environmental quality, its influence on global environmental health is certain to increase. Consequences of global environmental change such as habitat alteration, storms, and sea level rise will be particularly acute among Pacific Rim nations. Adverse health effects from arsenic exposure in Pacific Rim nations have been used to justify drinking water standards in the United States and elsewhere. As global manufacturing in the Pacific Rim increases, the centroid of global air quality and waste management issues will shift further toward Far Eastern nations. The Eleventh International Conference of the Pacific Basin Consortium (PBC) was held in September 2005 in Honolulu, Hawaii. The purpose of the conference was to bring together individuals to discuss regional challenges to sustainable growth. The historic emphasis of the conference on hazardous wastes in relation to human health makes the PBC an ideal forum for discussing technical aspects of sustainable economic growth in the Pacific region. That role is reflected in the 2005 PBC conference themes, which included management of arsenic in potable waters, air quality, climate change, pesticides, mercury, and electronics industry waste-each with emphasis on relationships to human health. Arsenic management exemplifies the manner in which the PBC can focus interdisciplinary discussion in a single technical area. The conference program provided talks on arsenic toxicology, treatment technologies, management of arsenic-bearing residuals from water treatment, and the probable societal costs and benefits of arsenic management.