Unacceptable "occupational" exposure to toxic agents among children in Ecuador

Neurodevelopment and exposure to neurotoxic metal(loid)s in environments polluted by mining, metal scrapping and smelters, and e-waste recycling in low and middle-income countries

This review covers a wide body of literature to gain an understanding of the impacts of informal activities related to metal extraction (primary mining and recycling) on early life exposure to neurotoxicants and on neurodevelopment. In primary mining, gold extraction with Hg amalgamation is the main environmental cause of Hg pollution in most artisanal small-scale gold mining (ASGM) activities around the world. Nevertheless, in Sub-Saharan Africa (SSA), Pb disrupted from gold-related ores, mining, and artisanal cookware production are an important neurotoxicant that seriously contaminates the affected population, with devastating effects on children. In e-waste recycling settings, the range of neurotoxic substances that contaminate mothers and children is wider than in primary mining environments. Thus, Hg and Pb are major pre- and postnatal neurotoxicants affecting children in the informal metal extraction activities and SSA countries show the highest record of human contamination and of neurotoxic effects on children. There are additional sources of neurotoxic contamination from mining and metal processing activities (cyanide tailing in South America and SSA) and/or co-exposure to Hg-containing products such as cosmetics (soaps and Hg-based skin lightning creams in Africa) and pediatric Thimerosal-containing vaccines (TCVs, that breaks down to ethyl-mercury) in current use in middle and low income countries. However, the action of these neurotoxicants (per se or in combination) on children needs more attention and research. Studies show a negative association between biomarkers of all environmental metal(loid)s (As, Cd, Hg, Mn, and Pb) studied and neurodevelopment in young children. Sadly, in many unregulated activities, child labor is widely employed, thus presenting an additional occupational exposure. Children living in polluted environments related to metal processing are disproportionately exposed to a wide range of co-occurring neurotoxic substances. The review showed compelling evidence from highly representative parts of the world (Africa, Asia, and Latin America) that the studied neurotoxic substances negatively affected areas of the brain associated with language, memory and executive function, as well as psychosocial behavior. Protecting the environment and children from unregulated and highly polluting metal extraction and processing are inextricably intertwined and deserve urgent attention.

Child labour and health: a systematic review

OBJECTIVES

This study aimed to synthesise the available knowledge, identify unexplored areas and discuss general limits of the published evidence. We focused on outcomes commonly hypothesised to be affected by child labour: nutritional status, harmful exposures and injuries.

METHODS

Four electronic databases (EMBASE, MEDLINE, Scopus, ISI Web of Science) were searched in November 2017. All articles published since 1996, without restrictions on language, were considered for inclusion.

RESULTS

Out of the 1090 abstracts initially identified by the search, 78 articles were selected for inclusion and reviewed. Most of the studies were conducted in Asia and South America, and only a third of them compared working children to a control group of non-working children. Child labour appears to be associated with poor nutritional status, diseases due to harmful exposures, and a higher prevalence of injuries.

CONCLUSIONS

Despite evidence for a negative relation between child work and health, the cross-sectional design of most studies limits the causal interpretation of existing findings. More rigorous observational studies are needed to confirm and better quantify these associations.

Gold Mining in Ecuador: A Cross-Sectional Assessment of Mercury in Urine and Medical Symptoms in Miners from Portovelo/Zaruma

Mercury is a toxic metal and is used in small scale gold mining. In Portovelo, Ecuador, mercury has been an environmental and health problem for decades. The target of this study was to assess the mercury concentration in the urine of miners from Portovelo/Zaruma to establish a prevalence of high values. Eight hundred and sixty-five (865) urine samples were collected and analysed for their mercury content, using cold vapor atom absorption spectroscopy. The prevalence of high mercury values (>25 μg/L) was estimated. Forty-four (44) miners with mercury levels >15 μg/L filled in a questionnaire for characteristics and possible confounders, and were examined for intoxication symptoms to establish the ten points medical score sum. The median urine value was 1.8 μg/L; 78.3% of miners were below 7 μg/L and were not at risk of an intoxication, whereas 5.9% of miners exceeded the limit of 25 μg/L and were probable to experience intoxication symptoms. The medical score sum had a range of 2 to 8 points with a median of 6. The low prevalence of high mercury concentrations shows that the politics and techniques to eliminate the use of mercury are being successfully implemented. Further studies are needed to identify factors enabling this process.

Essential Indicators Identifying Chronic Inorganic Mercury Intoxication: Pooled Analysis across Multiple Cross-Sectional Studies

Background

The continuous exposure to inorganic mercury vapour in artisanal small-scale gold mining (ASGM) areas leads to chronic health problems. It is therefore essential to have a quick, but reliable risk assessing tool to diagnose chronic inorganic mercury intoxication. This study re-evaluates the state-of-the-art toolkit to diagnose chronic inorganic mercury intoxication by analysing data from multiple pooled cross-sectional studies. The primary research question aims to reduce the currently used set of indicators without affecting essentially the capability to diagnose chronic inorganic mercury intoxication. In addition, a sensitivity analysis is performed on established biomonitoring exposure limits for mercury in blood, hair, urine and urine adjusted by creatinine, where the biomonitoring exposure limits are compared to thresholds most associated with chronic inorganic mercury intoxication in artisanal small-scale gold mining.

Methods

Health data from miners and community members in Indonesia, Tanzania and Zimbabwe were obtained as part of the Global Mercury Project and pooled into one dataset together with their biomarkers mercury in urine, blood and hair. The individual prognostic impact of the indicators on the diagnosis of mercury intoxication is quantified using logistic regression models. The selection is performed by a stepwise forward/backward selection. Different models are compared based on the Bayesian information criterion (BIC) and Cohen`s kappa is used to evaluate the level of agreement between the diagnosis of mercury intoxication based on the currently used set of indicators and the result based on our reduced set of indicators. The sensitivity analysis of biomarker exposure limits of mercury is based on a sequence of chi square tests.

Results

The variable selection in logistic regression reduced the number of medical indicators from thirteen to ten in addition to the biomarkers. The estimated level of agreement using ten of thirteen medical indicators and all four biomarkers to diagnose chronic inorganic mercury intoxication yields a Cohen`s Kappa of 0.87. While in an additional stepwise selection the biomarker blood was not selected, the level of agreement based on ten medical indicators and only the three biomarkers urine, urine/creatinine and hair reduced Cohen`s Kappa to 0.46. The optimal cut-point for the biomarkers blood, hair, urine and urine/creatinine were estimated at 11. 6 μg/l, 3.84 μg/g, 24.4 μg/l and 4.26 μg/g, respectively.

Conclusion

The results show that a reduction down to only ten indicators still allows a reliable diagnosis of chronic inorganic mercury intoxication. This reduction of indicators will simplify health assessments in artisanal small-scale gold mining areas.

Sources of Mercury Exposure to Children in Low- and Middle-Income Countries

BACKGROUND

Many children in low- and middle-income countries face enhanced risks of exposure to contaminants via the environment, parental occupation, and other routes. While mercury (Hg) is a global pollutant whose transport properties allow it to have an impact even in pristine areas, the presence of significant Hg sources in the developing world can cause localized effects that are more severe than those observed in other areas.

OBJECTIVES

This paper provides a narrative review of sources of Hg exposure to people in the developing world with a particular focus on children, and presents an overview of key aspects to this important issue.

METHODS

We searched Web of Knowledge and Google Scholar using keywords including combinations of "mercury" and one or more of the following: "children," "exposure," "breast milk," "artisanal mining," "prenatal," "religion," "medicine," "dental amalgam," "chlor-alkali," "VCM," "vaccine," "e-waste," "industry," "beauty," "cosmetics," "strategies," "child labor," "costs," and "developing countries" to find peer-reviewed articles pertaining to Hg exposure in the developing world.

RESULTS

Sources of Hg exposure include mining, consumption, industrial operations, religious practices, traditional medicines, beauty products, vaccines, dental amalgams, and waste scavenging and recycling.

CONCLUSION

Children in the developing world are often subject to higher levels of Hg exposure than those living in developed countries due to the higher prevalence of Hg-intensive industrial processes and consumer products, lack of environmental regulation, and limits in mobility and food choices, among other factors. This issue can be addressed through additional research to fill in data gaps on exposure sources, establish sound and enforceable policies, and increase education and participation in affected communities. Challenges to addressing this problem include limited resources for needed equipment, training, and manpower to implement solutions.

Mercury exposure and children's health

Acute or chronic mercury exposure can cause adverse effects during any period of development. Mercury is a highly toxic element; there is no known safe level of exposure. Ideally, neither children nor adults should have any mercury in their bodies because it provides no physiological benefit. Prenatal and postnatal mercury exposures occur frequently in many different ways. Pediatricians, nurses, and other health care providers should understand the scope of mercury exposures and health problems among children and be prepared to handle mercury exposures in medical practice. Prevention is the key to reducing mercury poisoning. Mercury exists in different chemical forms: elemental (or metallic), inorganic, and organic (methylmercury and ethyl mercury). Mercury exposure can cause acute and chronic intoxication at low levels of exposure. Mercury is neuro-, nephro-, and immunotoxic. The development of the child in utero and early in life is at particular risk. Mercury is ubiquitous and persistent. Mercury is a global pollutant, bio-accumulating, mainly through the aquatic food chain, resulting in a serious health hazard for children. This article provides an extensive review of mercury exposure and children's health.

Human mercury exposure and adverse health effects in the Amazon: a review

This paper examines issues of human mercury (Hg) exposure and adverse health effects throughout the Amazon region. An extensive review was conducted using bibliographic indexes as well as secondary sources. There are several sources of Hg (mining, deforestation, reservoirs), and exposure takes place through inhalation or from fish consumption. There is a wide range of exposure, with mean hair-Hg levels above 15 microg/g in several Amazonian communities, placing them among the highest reported levels in the world today. Dietary Hg intake has been estimated in the vicinity of 1-2 microg/kg/day, considerably higher than the USEPA RfD of 0.1 microg/kg/day or the World Health Organization recommendation of 0.23 microg/kg/day. Neurobehavioral deficits and, in some cases, clinical signs have been reported both for adults and children in relation to Hg exposure in several Amazonian countries. There is also some evidence of cytogenetic damage, immune alterations, and cardiovascular toxicity. Since fish provide a highly nutritious food source, there is an urgent need to find realistic and feasible solutions that will reduce exposure and toxic risk, while maintaining healthy traditional dietary habits and preserving this unique biodiversity.

Comparative analysis of zinc protoporphyrin and blood lead levels in lead-exposed Andean children

OBJECTIVES

The objective of this study was to investigate the zinc protoporphyrin/heme ratio (ZPP/heme) as a biomarker for chronic lead (Pb) poisoning in children with a history of high Pb exposure.

DESIGN AND METHODS

ZPP/heme ratio was measured in blood samples from 78 children (44 females and 34 males) with persistent Pb exposure from Pb glazing of ceramics in a local cottage industry in the Andes Mountains of Ecuador.

RESULTS

Mean blood lead (PbB) level was 26.4 microg/dL (SD: 23.2; range: 4.0-107.0), and the mean ZPP/heme ratio was 152.4 micromol/mol (SD: 190.6; range: 36.0-1064.0). A regression analysis of PbB level and ZPP/heme ratio revealed a significant association (r=0.761, p= <0.0001), with the logZPP showing a higher correlation with PbB (r=0.869, p= <0.0001). The ZZP/heme ratio decreased significantly with increasing age (ANOVA, p=0.030). The mean ZPP/heme ratios for females and males were 139.6 and 169.0 micromol/mol, respectively, and were not statistically different (t-test, p=0.504).

CONCLUSION

The elevated ZPP/heme ratios, coupled with high PbB levels observed in this cohort of Andean children of Pb-glazing workers, suggest chronic Pb intoxication and probable iron deficiency.

Children's environment and health in Latin America: the Ecuadorian case

Environmental health problems of children in Latin America and Ecuador are complex due to the close relationship that exists between social and environmental factors. Extended poverty and basic problems, such as the lack of drinking water and sanitation, are common. Infectious diseases are the greatest cause of morbidity and mortality among children. Development in industry and the introduction of chemical substances in agriculture add new risks including pesticide use, heavy metal exposure, and air pollution. Major problems can be divided into (a) lack of basic infrastructure, (b) poor living conditions, (c) specific environmental problems, and (d) child labor. Reproductive health disorders are frequent in developing countries like Ecuador. Issues related to children's health should consider new approaches, creative methodologies, and the search for independent predictors to separate environmental from social problems. Only with knowledge of the specific contribution of each factor, can it be possible to develop a strategy for prevention.

Occupational versus environmental and lifestyle exposures of children and adolescents in the European Union

There is recent international concern about specific exposures of children and adolescents to toxicants. In general, the situation within the European Union appears as follows. (i) OCCUPATIONAL EXPOSURE: Due to regulatory measures, there are almost no toxicologically significant occupational exposure situations of children to chemical toxicants. This contrasts to the situation in developing countries. There is also strict regulation of occupational exposure of adolescents (aged under 18). In consequence, the number of potentially exposed adolescents has been minimised. (ii) ENVIRONMENTAL EXPOSURE: Specific concern is directed towards exposures of infants, especially to neurotoxic heavy metals and carcinogens, and there is much regional differentiation of environmental exposures. (iii) FOOD: Recent research results are indicative of the general progress made in the field of food safety. (iv) INCIDENTAL ACUTE EXPOSURE: Besides drugs, household chemicals are a source of incidental acute intoxications in children. In Germany, there has been a particular focus on ingestion of lamp petroleum oils since 1989. (v)

LIFESTYLE

Paramount problems are associated with increasing consumption of tobacco (mean age of starting smoking in Germany: 13.6 years), alcohol (percentage of addicts at ages 12-24 in Germany 6%) and cannabis among adolescents, calling for new ways of risk communication. In general, it will be necessary to consider children of different ages as separate risk groups.

Pesticide usage and health consequences for women in developing countries: out of sight, out of mind?

Pesticide exposures of women in developing countries are aggravated by economic policy changes associated with structural adjustment programs and globalization. Women in these countries, particularly in the agricultural sector, are increasingly exposed. Since they are concentrated in the most marginal positions in the formal and informal workforces, and production is organized in a gender-specific way, opportunities for women to control their exposures are limited. Data from developing countries show that: 1) women's exposures to pesticides are significantly higher than is recognized; 2) poisonings and other pesticide-related injuries are greatly underestimated for women; 3) for a given adverse outcome from exposure, the experience of that outcome is gender-discriminatory; 4) erroneous risk perception increases women's exposures. The hiatus in knowledge of gender-specific exposures and effects is related to gender biases in the nature of epidemiologic inquiry and in the literature, and the gendered nature of health workers' practices and surveillance. Recommendations are made for strong, independent organizations that provide opportunities for women to control their environments, and the factors affecting their health, as well as gender-sensitive research to address the particularities of women's pesticide exposures.

Biological monitoring of young workers exposed to polycyclic aromatic hydrocarbons in engine repair workshops

Several polycyclic aromatic hydrocarbons (PAHs) are carcinogenic in rodents, while exposure to these compounds has been associated with various types of human cancer. Engine exhaust and used engine oils are major PAH sources in engine repair workshops. Urinary 1-hydroxypyrene (1-OHP) levels and some genotoxicity parameters (sister-chromatid exchange, SCE; micronucleus, MN) have been compared among engine repair workers (n = 61, age: between 13 and 18) and workers not occupationally exposed to PAH (n = 30, age: between 13 and 19). The mean value (+/- S.E.) of urinary 1-OHP excretions of workers was 4.71 +/- 0.53 micromol/mol creatinine and also mean urinary 1-OHP for controls was found to be as 1.55 +/- 0.28 micromol/mol creatinine. The mean values (+/- S.E.) of SCE frequency per cell in peripheral lymphocytes from the workers and controls were 4.47 +/- 0.09 and 4.06 +/- 0.16, respectively (p < 0.05). The mean (+/- S.E.) MN (per thousand) frequencies in peripheral lymphocytes from the workers and controls were 1.87 +/- 0.04 and 1.56 +/- 0.06, respectively (p < 0.0001). The effect of smoking for the above parameters were also evaluated.