Blood lead levels in low-income and middle-income countries: a systematic review.

BACKGROUND: Since the global phase-out of leaded petrol, reports have suggested that lead exposure remains substantial or is increasing in some low-income and middle-income countries (LMICs). However, few studies have attempted to systematically assess blood lead levels over the full range of LMICs. We aimed to describe values for blood lead level in LMICs. METHODS: In this systematic review, we searched PubMed for studies published between Jan 1, 2010, and Oct 31, 2019, that reported blood lead levels in the 137 countries in World Bank LMIC groupings. Studies were reviewed for inclusion if they contained blood lead level data from human populations residing in any given country; comprised at least 30 participants; presented blood lead level data derived from venous, capillary, or umbilical cord samples of whole blood; had data that were collected after Dec 31, 2004; and were published in English. Data on blood lead level were extracted and pooled, as appropriate, to make country-specific estimates of the distribution of background blood lead levels among children and adults, along with information on specific sources of exposure where available. This study is registered with PROSPERO, number CRD42018108706. FINDINGS: Our search yielded 12 695 studies, of which 520 were eligible for inclusion (1100 sampled populations from 49 countries comprising 1 003 455 individuals). Pooled mean blood lead concentrations in children ranged from 1·66 µg/dL (SD 3·31) in Ethiopia to 9·30 µg/dL (11·73) in Palestine, and in adults from 0·39 µg/dL (1·25) in Sudan to 11·36 µg/dL (5·20) in Pakistan. Background values for blood lead level in children could be pooled in 34 countries and were used to estimate background distributions for 1·30 billion of them. 632 million children (95% CI 394 million-780 million; 48·5%) were estimated to have a blood lead level exceeding the US Centers for Disease Control's reference value of 5 µg/dL. Major sources of lead exposure were informal lead acid battery recycling and manufacture, metal mining and processing, electronic waste, and the use of lead as a food adulterant, primarily in spices. INTERPRETATION: Many children have a blood lead level exceeding 5 µg/dL in LMICs, despite leaded petrol phase-outs. Given the toxicity of lead, even at low amounts of exposure, urgent attention is required to control exposures and to expand population-based sampling in countries with no or scant data. FUNDING: This work was supported by the United States Agency for International Development (Cooperative Agreement number AID-OAA-A-16-00019).

Inventory of Obsolete Pesticide Warehouses in Tajikistan and Implications for Removal of Contaminated Soil.

BACKGROUND: Tajikistan is an agrarian-industrial republic. A large portion of the Tajikistan economy relies on agriculture. With the rise of agriculture, especially cotton production, came the widespread use of pesticides. Abandoned and unsupervised pesticide storage warehouses have become a health and environmental problem. In many cases such sites, as well as significant areas of pesticide-contaminated land, remain accessible to the public. A survey and analysis of 26 former pesticide storage warehouse sites across Tajikistan revealed a country-wide pesticide exposure problem that threatens the health of vulnerable populations. Infrastructure and local governance issues are barriers to addressing this health crisis for rural residents. OBJECTIVES: The purpose of this article is to describe the issues surrounding former pesticide storage warehouses and their effect on the health of the population of Tajikistan. MATERIALS AND METHODS: In 2012, the non-governmental organization (NGO), Pure Earth (formerly Blacksmith Institute), with the financial support of the Food and Agriculture Organization of the United Nations (FAO), Green Cross Switzerland and the European Union conducted surveys of 26 pesticide warehouses located throughout Tajikistan. The survey included detailed site assessments, including analysis of the maintenance of chemicals and soil testing. RESULTS: Soil samples taken from the studied sites exceeded maximum permissible concentrations referenced by Pure Earth by several hundred times for dichlorodiphenyl-trichloroethane (DDT) and hexachlorocyclohexane (HCH), as well as aldrin and dieldrin. Even the most polluted sites had families living on the premises. CONCLUSIONS: Pesticide contamination in Tajikistan is a serious and ongoing problem that requires the attention of local, state governments, and international non-governmental organizations. We recommend the development of a government-sponsored public education campaign to inform the population about the potential risks of exposure to obsolete pesticides. The dangers of agricultural use, former storage warehouses and disposal areas should be addressed. In addition, data from the 2012 surveys of 26 warehouses should be used to prioritize the four high-risk sites and develop preliminary clean-up plans for contaminated soil around warehouses to present to government ministries and NGOs. COMPETING INTERESTS: The authors declare no competing financial interests.