Lead Hazards for Pregnant Women and Children: Part 2: More can still be done to reduce the chance of exposure to lead in at-risk populations.:

Toxicity and bioremediation of the lead: a critical review

Lead is a naturally occurring, bluish-gray metal that is found in small quantities in the earth's crust. The existing literature demonstrates that non-biodegradable character and continuous use results in accumulation of lead concentration in the environment and causes various ill effects such as neurotoxicity, change in psychological and behavioral development of different organisms. Nowadays the most effective technique in the revival of the environment is bioremediation and it is environmentally friendly and cost-effective. Bacterial strains such as Oceanobacillus profundus and Lactobacillus acidophilus ATCC4356 have the ability to reduce lead 97% and 73.9%, respectively. Similarly some species of algae and fungal strains also showed lead removal efficiency as 74% (spirulina), 97.1% (Chlorella kessleri), 95.5% (Penicillium janthinillum) and 86% (Aspergillus flavus). Biodegradation of lead by various microbes would be the most efficient and sustainable approach. This review focuses on toxicity, fate of lead in the environment and its microbial degradation.

Chemical analysis of calabash chalk and its effect on locomotor activities and behavior in Swiss albino mice

Continuous exposure of young women to calabash chalk, especially at child-bearing age, necessitated this study to analyze the chemical constituents of calabash chalk and to evaluate its effect on locomotor activities and behavior in Swiss albino mice. Dried cubes of calabash chalk were purchased and analyzed by atomic and flame atomic absorption spectrophotometer. Twenty-four Swiss-albino mice were taken and divided into four groups: control (1 ml distilled water) and three treated groups with the doses of 200 mg/kg, 400 mg/kg, and 600 mg/kg of calabash chalk suspension, respectively, by oral gavage. Hole Cross, Hole Board, and Open Field tests were performed to evaluate the locomotor activities, behavior, and anxiety along with measurement of body weight. The data were analyzed by SPSS-software. Chemical analysis of calabash chalk showed the presence of trace elements along with some heavy metals such as lead (19.26 ppm), Chromium (34.73 ppm), and arsenic (4.57 ppm). After 21 days of oral administration of calabash chalk, the study showed a significant decrease in body weight in the treated groups of mice (p < 0.01). Decreased locomotor activities were also observed in all three experiments. Significantly decreased locomotion and behaviors were also observed in the hole crossing, line crossing, head dipping, grooming, rearing, stretch attend, central square entry, central square duration, defecation, and urination, in a dose-dependent manner (p < 0.01). These effects also prove the anxiogenic behavior of calabash chalk in albino mice. Heavy metals are believed to be harmful to the brain and responsible for cognitive dysfunction and elevated anxiety. In this study, decreased body weight in mice may occur due to disorders in hunger and thirst centers of the brain by heavy metals. Therefore, heavy metals may be responsible for muscle weakness, decreased locomotor activities, and axiogenic effects of mice.

Cereal and Juice, Lead and Arsenic, Our Children at Risk: A Call for the FDA to Re-Evaluate the Allowable Limits of Lead and Arsenic That Children May Ingest

Eliminating heavy metal contamination of foods is a goal yet to be achieved in the U.S. In recent months, efforts have been underway to have the Food and Drug Administration (FDA) re-evaluate the permissible limits of lead (Pb) and arsenic (As) allowable in cereals and juices aimed for consumption by children. This report discusses the recent scientific literature that support proposed revisions in these limits. It presents proactive suggestions for the FDA to consider in its response to concerns of ongoing Pb and As exposures in food and drinks. While more scientific studies are needed to better define ‘safe’ levels of Pb and As exposures and ingestion of these elements in general are neurotoxic, the higher sensitivity of children to these toxic elements makes it imperative that the FDA adjust standards to be most protective of infants, toddlers, and children.

Association between lead source exposure and blood lead levels in some lead manufacturing countries: A systematic review and meta-analysis

Lead is one of the 10 most toxic chemicals of greatest concern for its effects on public health. Predominantly, in undeveloped countries, high blood lead levels (BLLs) persist in the population. To develop intervention strategies that may reduce lead exposure in populations, it is a priority to know the sources of lead pollution. The objective of this critical review and meta-analysis is to assess whether there is an association between different sources of lead exposure and the mean difference in blood lead levels in people exposed. To identify the major lead source exposure, a statistical analysis was performed on selection studies. This investigation reveals the limited information available on the sources of lead in Mexico and other lead producer countries, such as Croatia, Ecuador, Brazil, South Korea, India, Nigeria, Turkey, and China. Meta-analysis could be performed only in battery, smelting mining, and glazed ceramic workers. Battery manufacturing workers have the highest mean difference level of lead in their blood worldwide. Mexico has the second highest mean difference BLL in battery workers in the world. An interesting difference between the mean difference in BLL in mining workers from uncontrolled industry (-39.38) and controlled industry (-5.68) was found. This difference highlighted the success of applying strict control of lead sources and community education to reduce BLL and its potential harmful effects on human health and the environment. Children living near mining sites have the highest mean difference BLL (-11.1). This analysis may aid in assessing the source of lead exposure associated with a range of BLLs in people. Furthermore, this review highlights several social and cultural patterns associated with lead exposure and lead levels in control populations. These results could help to develop international lead regulations and appropriate public health guidelines to protect people around the world.

Sources of lead exposure in various countries

This review evaluates the sources of lead exposure worldwide. Studies from searches relating to sources of lead exposure in various countries within different regional zones were reviewed. Results indicated that in Nigeria, exposure sources include electronic waste, paint and batteries. In Mexico exposure sources include glazed ceramics, lead contaminated utensils and lead contaminated water, for India lead sources include cosmetics and traditional medicines. Sources of lead exposure in China include e-waste, traditional medicines and industrial emissions. In France, exposure sources included lead paint from older homes, imported ceramics and cosmetics and industrial emissions. Australia's exposure sources include paint, dust, imported toys and traditional medicines. Finally, in the United States exposure sources included paint, the industrial legacy of lead exposure and batteries. In high-income countries (HICs) the legacy of lead exposure keeps populations continuously exposed. In lower- and middle-income countries (LMICs), in addition to the legacy of lead exposure, lack of regulations or the inability to enforce regulations keeps populations exposed. In all, evidence suggests that lead exposure remains an issue of public health significance in both HIC and LMIC.

Hypospadias Risk from Maternal Residential Exposure to Heavy Metal Hazardous Air Pollutants

Objective: Investigate whether residential prenatal exposure to heavy metal hazardous air pollutants (HMHAPs) is associated with an increased risk of hypospadias. Methods: Data on non-syndromic hypospadias cases (n = 8981) and control patients delivered in Texas were obtained from the Texas Birth Defects Registry and matched 1:10 by birth year. Average exposure concentrations of HMHAPs were obtained from the 2005 U.S. Environmental Protection Agency National-Scale Air Toxics Assessment and categorized into quintiles. Odds ratios and 95% confidence intervals were estimated. STROBE reporting guidelines were followed. Results: We observed associations between hypospadias and prenatal HMHAP exposure. Manganese demonstrated significant increased risk of hypospadias at the medium, medium-high and high exposure quintiles; lead in the medium-high and high exposure quintiles. Cadmium, mercury and nickel demonstrated a significant inverted "U-shaped" association for exposures with significant associations in the medium and medium-high quintiles but not in the medium-low and high quintiles. Arsenic and chromium demonstrated a significant bivalent association for risk of hypospadias in a lower quintile as well as a higher quintile with non-significant intermediate quintiles. Conclusions: Using data from one of the world's largest active surveillance birth defects registries, we identified significant associations between hypospadias and HMHAP exposures. These results should be used in counseling for maternal demographic risk factors as well as avoidance of heavy metals and their sources.