Reduction In Lead Concentration Research Articles

Health and Economic Consequences of Lead Exposure Associated with Products and Services Provided by the Informal Economy.

In low- and middle-income countries (LMICs), the presence of an informal economy can lead to human exposure to toxic metals such as lead (Pb). This paper demonstrates the local health and economic benefits of modifying practices within the informal economic sector in Madagascar. Specifically, leaded components in 504 locally manufactured household water pumps were replaced with unleaded components. Prior to the intervention, 32% of the household systems exhibited lead concentrations above the World Health Organization (WHO) provisional drinking water guideline of 10 μg/L, but after the intervention, fewer than 3% of the systems were in exceedance. The reduction of lead concentration is modeled to reduce the fraction of children with elevated BLLs (>5 μg/dL) from 34 to 13%. The reduction in BLLs is estimated to provide an average economic benefit of US$11 800 per child based on predicted increases in lifetime productivity. This corresponds to a total benefit of US$8.7 million for the 730 children aged 1-5 associated with the pumps, representing a return on investment of greater than 1000-to-1. Results demonstrate how the formation of partnerships between public, private, and civil society entities, as suggested by UN Sustainable Development Goal 17, can realize important local economic and health benefits in LMICs.

DETERMINATION OF EDTA IMPACT ON THE CONTENT AND DISTRIBUTION OF LEAD IN THE SYSTEM «SOIL-PLANT» DURING PHYTOREMEDIATION

Like any other biogeochemical process, the transition of heavy metal ions from the soil through the root system to the terrestrial part of the plants is characterized by the rate, which depends on a number of factors. These factors include: the physicochemical characteristics of the soil itself (pH, humus content); properties of heavy metal ion (radius, oxidation number, surrounding ligands); ambient temperature, daylight hours; morphological features of plants. In the present paper, at the same values of the factors of first three groups, the ability of some species of agricultural plants (oats, white mustard, maize and sunflower) to extract lead compounds from the soil and accumulate them in the underground and ground parts was investigated. The results of analysis showed that the lead content in the soil in all cases after the 30-day growing cycle was decreased. The most significant decrease in the concentration of heavy metal in the soil was observed for the samples where oats were grown. The smallest change is for the samples where the sunflower was grown. It was found that, under the conditions of the experiment, the efficiency of lead extraction increases with its concentration in the soil. Addition of EDTA to contaminated soil increases the rate of absorption of lead compounds by plants. For maize, a lead reduction of 5% was observed when EDTA was added to the soil. For mustard and oats, the lead content of the soil was almost unchanged when EDTA was added. The most significant reduction in lead concentration with the addition of EDTA was observed for the soil on which the sunflower was grown - by 63%. The calculations showed that during the first 30 days of growth, the terrestrial parts of the studied plants absorb only about 0.1% of the total lead content in the soil-plant system. According to the results of the conducted studies, the cumulation coefficients for the investigated crops were determined: for sunflower the maximum value was 2.47 (in the presence of EDTA), for mustard - 0.94, for corn - 0.79, for oats - 1.58. Therefore, oats and sunflowers have the best cumulative properties among the studied crops. Maximum lead uptake was set for sunflower in the presence of EDTA.

Probabilistic modeling of aggregate lead exposure in children of urban China using an adapted IEUBK model.

Lead, a ubiquitous pollutant throughout the environment, is confirmed to be neurotoxic for children by pulmonary and oral routes. As preschool children in China continue to be exposed to lead, we analyzed the available biomonitoring data for preschool children in urban China collected in the period 2004-2014 through a literature review. To identify apportionment of lead exposure sources for urban children in China, we modified the IEUBK model with a Monte Carlo module to assess the uncertainty and variability of the model output based on limited available exposure data and compared the simulated blood lead levels with the observed ones obtained through literature review. Although children's blood lead levels in urban China decreased statistically over time for the included studies, changes in blood lead levels in three economic zones and seven age groups except for two age-specific groups were no longer significant. The GM-predicted BLLs and the GM-observed BLLs agreed within 1μg/dL for all fourteen cities. The 95% CIs for the predicted GMs and the observed distribution (GM±GSD) overlapped substantially. These results demonstrated the plausibility of blood lead prediction provided by the adapted IEUBK model. Lead exposure estimates for diet, soil/dust, air, and drinking water were 12.01±6.27μg/day, 2.69±0.89μg/day, 0.20±0.15μg/day, and 0.029±0.012μg/day, respectively. These findings showed that the reduction of lead concentrations in grains and vegetables would be beneficial to limit the risk of dietary lead exposure for a large proportion of preschool children in urban China.

Effect of calcium supplementation on lead-induced genotoxicity and bioaccumulation in suckling Wistar rats

The study investigated the effect of calcium (Ca) supplementation on lead-induced toxicity in suckling male Wistar rats. The sucklings were exposed to lead acetate (5 mg/kg b wt./week) orally for a period of six weeks. The unexposed group of sucklings was the negative control. Out of the lead-exposed groups, two groups were supplemented with Ca at 3% and 6% as CaHPO4 × 2H2O in suspension in cow's milk. The artificial feeding regimen was followed for 7 h each day for 6 weeks. Sucklings exposed to lead with Ca supplementation recorded a significantly higher increase in body weight and a significant reduction of lead concentration in all tissues. The lead-induced histopathological alterations in the liver and kidney were also reversed with Ca supplementation. Sodium rhodizonate staining of liver sections showed distinct presence of lead granules in the group exposed to lead while the Ca-supplemented groups were comparable to the control. Lead exposure reduced the expression of rad 51 in the testis and liver which was markedly enhanced with Ca supplementation and was restored to the level in the control. Thus, Ca supplementation during the suckling period was effective in ameliorating the lead-induced toxicity.

Lead concentrations and isotope ratios in street dust in major cities in Greece in relation to the use of lead in petrol

Until recently, the most important source of environmental lead pollution in cities was thought to come from the combustion of leaded petrol. A simple way to monitor the extent of this phenomenon, used in a number of studies in the past, has been to measure lead levels in street dust. Nowadays, it would be expected that lead concentrations in urban dust would have decreased from earlier values, following the progressive reduction of lead in petrol over the past few years, and this hypothesis has recently been confirmed in Manchester, UK. The object of the present work is to determine levels of lead pollution in cities in Greece on 1997 and, if possible, to discover whether similar reductions in lead concentrations have occurred there also. Surveys have been conducted in Thessaloniki, Athens and Piraeus. Samples of roadside dust were collected from streets (categorised by traffic density), national gardens and school playgrounds, and lead was extracted by digestion with concentrated nitric acid. Lead concentrations were determined by graphite furnace atomic absorption spectrometry and lead isotope ratios measured by inductively coupled plasma mass spectrometry. Results for Thessaloniki showed that mean lead concentrations in all categories of location are similar to present levels in Manchester. Further, lead concentrations in dust in the busiest streets in Thessaloniki have fallen by about 55% since a previous study 17 years ago. In Athens and Piraeus, the lead levels in street dust are much higher and significant differences were observed between the various types of street. In particular, it was observed that lead levels in school playgrounds in these two cities were much higher than in similar locations in Thessaloniki and Manchester, with a possible hazard to children. Isotope ratio measurements showed that Thessaloniki's lead is isotopically distinct from that found in Athens and Piraeus, which presumably reflects differences in sources of supply.

Isotopic characterisation of lead deposited 1989-2001 at two upland Scottish locations.

The isotopic composition of lead collected with grass samples taken over the period 1989-2001 from plots at two upland locations (Glensaugh in north east and Hartwood in central Scotland) has been determined using thermal ionisation mass spectrometry. Although marked reductions in lead concentrations in grass were observed at Glensaugh in the initial three years, subsequently concentrations have remained relatively constant (1-3 microg g(-1)) in all plots to the present day. The one exception was a roadside plot at Hartwood which showed a large reduction from 1.0 microg g(-1) in 1999 to 0.2 microg g(-1) in 2000 following the abolition of petrol lead in the UK at the beginning of 2000. The total concentrations at this plot were consistently lower than those found at plots away from road traffic but exposed to the prevailing wind direction. The 206Pb/207Pb ratio increased steadily at all the plots throughout the period of the study indicating the reducing influence of petrol lead but the changes were not as great as might be expected with the decrease in the use of leaded petrol. Assuming the collected lead had only two sources, petrol lead and a diffuse background "industrial" lead, the proportion of petrol lead was only in the range 17-69% for roadside samples and 0-39% in other samples. A substantial proportion of deposited lead, therefore, now has its origin other than in petrol. Mixing curves indicate that whereas the lead deposited at Glensaugh could be defined by only two end members, that at Hartwood needs more than two components in the mixture. The results also suggest that although petrol lead has been eliminated, traffic is still a source of lead and another source defined as "traffic lead" should be considered.

96/03324 - Reduction of lead concentrations in vegetables grown in Tarragone Province, Spain, as a consequence of reduction of lead in gasoline

96/03324 - Reduction of lead concentrations in vegetables grown in Tarragone Province, Spain, as a consequence of reduction of lead in gasoline

Reduction of lead concentrations in vegetables grown in Tarragona Province, Spain, as a consequence of reduction of lead in gasoline

Lead concentrations were determined in 350 samples belonging to 13 different species of vegetables from Tarragona Province, Spain. The samples were subjected to lead analyses by graphite furnace atomic absorption spectrophotometry. During the period 1989–1994, an average decrease for lead concentrations of 69% was estimated. Spinach showed the lowest reduction in lead content (6%), while the highest decreases were observed for onion (87%) and leek (90%). Taking into account the average consumption of vegetable foodstuffs by the population of Tarragona Province, the daily lead intake through edible vegetables was reduced from 41.5 μg/d in 1989 to 10.6 μg/d in 1994. The results of the current study demonstrate a substantial decline in the lead levels of vegetables from Tarragona Province. The major cause of this decline is most likely the reduced leaded gasoline consumption.