Health risk for children from lead and cadmium near a non-ferrous smelter in Bulgaria

Potential health risks of inhaled toxic elements and risk sources during different COVID-19 lockdown stages in Linfen, China

Levels of toxic elements in ambient PM_2.5 were measured from 29 October 2019 to 30 March 2020 in Linfen, China, to assess the health risks they posed and to identify critical risk sources during different periods of the COVID-19 lockdown and haze episodes using positive matrix factorization (PMF) and a health-risk assessment model. The mean PM_2.5 concentration during the study period was 145 μg/m³, and the 10 investigated toxic elements accounted for 0.31% of the PM_2.5 mass. The total non-cancer risk (HI) and total cancer risk (TCR) of the selected toxic elements exceed the US EPA limits for children and adults. The HI for children was 2.3 times that for adults for all periods, which is likely due to the high inhalation rate per unit body weight for children. While the TCR for adults was 1.7 times that of children, which is mainly attributed to potential longer exposure duration for adults. The HI and TCR of the toxic elements during full lockdown were reduced by 66% and 58%, respectively, compared to their pre-lockdown levels. The HI and TCR were primarily attributable to Mn and As, respectively. Health risks during haze episodes were significantly higher than the average levels during COVID-19 lockdowns, though the HI and TCR of the selected toxic elements during full-lockdown haze episodes were 68% and 17% lower, respectively, than were the levels during pre-lockdown haze episodes. During the study period, fugitive dust and steel-related smelting were the highest contributors to HI and TCR, respectively, and decreased in these emission sources contributed the most to the lower health risks observed during the full lockdown. There, the control of these sources is critical to effectively reduce public health risks.

Heavy metal pollution and health risk assessment of agricultural soil near a smelter in an industrial city in China

To assess heavy metal pollution and human health risk, a total of 28 topsoil samples were collected during four seasons from seven agricultural soil sites near a famous smelter in Jiyuan, China. The maximum concentrations of Cd, Pb, Hg, As, Zn, Cu, Ni, and Cr were 26.00, 2601.00, 3.29, 65.00, 410.00, 156.30, 54.80, and 73.60 mg kg^-1, respectively. Compared with the sampling site nearest to the smelter, the concentrations of six metals at the farthest site were decreased significantly (P < 0.05). All sites were heavily contaminated, with Nemerow index (P) >3.0, and all sites had very high ecological risks related to Cd and Hg. The non-carcinogenic risk for children (based on combined exposure to the eight metals) was above the safety level. The carcinogenic risk of As for adults (8.98 × 10^-6) and children (1.49 × 10^-5) exceeded the acceptable level (1 × 10^-6). Results suggest a serious health risk in the polluted areas, particularly for children.Abbreviation Cd: Cadmium; Pb: Lead; Hg: Mercury; As: Arsenic; Zn: Zinc; Cu: Copper; Ni: Nickel; Cr: Chromium; P: Nemerow index; RI: Potential ecological risk index; E_i: Monomial potential ecological risk of a specific heavy metal; HI: non-carcinogenic hazard index; CR: Carcinogenic risk; TN: Total nitrogen; TP: Total phosphorus; OM: Organic matter; MC: Moisture content; ADD: Average daily dose.

Association between prenatal cadmium exposure and cognitive development of offspring: A systematic review

Due to the lack of substantial and reliable evidence on the relationship between prenatal cadmium (Cd) exposure and cognitive development of offspring, we conducted the present systematic review. Leading electronic databases-including Pubmed, Embase, Web of Science, the Cochrane Library, PsycINFO, PsycARTICLES, and the Psychology and Behavioral Sciences Collection-were searched on February 14, 2019. There was no date, study design or language limit imposed in our search. All of the included studies satisfied our predetermined study population (pregnant mothers and their offspring), exposure (prenatal Cd exposure), and outcome measurements (adverse effects on cognitive development). The quality assessment for the included studies was conducted with the Newcastle-Ottawa Scale (NOS). Nine prospective cohort studies met the inclusion criteria, and six of them were assessed to be of high quality based on the NOS (NOS score ≥ 7). The prenatal Cd exposure was tested in maternal blood samples (4/9), umbilical cord blood samples (4/9), or maternal urinary samples (3/9). Among the nine studies included, six reported at least one inverse association between prenatal Cd exposure and the cognitive development of offspring, mainly in terms of language development (4/8), performance ability development (3/5), and general cognitive development (3/8). Furthermore, among six studies with high methodological quality (NOS score ≥ 7), prenatal Cd exposure was reported to be associated with language development in three studies (3/5), performance ability development in three studies (3/4), and general cognitive development in three studies (3/5). This systematic review provides convincing evidence that prenatal exposure to Cd is inversely associated with neurodevelopment of offspring. Larger prospective studies using standardized criteria and assessments of cognitive development are needed to confirm the dose-response effect and gender difference of prenatal Cd exposure on cognitive development of offspring.

Source apportionment of PM2.5 using positive matrix factorization (PMF) at a rural site in Korea

The sources of different pollutants contributing to ambient fine particles (PM_2.5) on Daebu Island, Korea, were estimated. Twenty four hour integrated filter samples were collected from May 21-November 1, 2016, and analyzed for organic carbon, elemental carbon, ions, and trace elements. Positive matrix factorization was conducted on the PM_2.5 chemical speciation data from the samples to define the pathways and sources of PM_2.5 at the sampling site. A total of 80 samples and 24 chemical species were used to run the model and a total of nine sources were identified: secondary sulfate (29.0%), mobile (22.0%), secondary nitrate (13.2%), oil combustion (10.1%), coal combustion (9.4%), aged sea salt (7.9%), soil (5.6%), non-ferrous smelting (1.7%), and industrial activity (1.1%). Conditional probability and potential source contribution functions were then used to determine whether these sources were local or came from pollutants transported over long-range distances. The anthropogenic sources came from local emissions and originated from both industrialized and metropolitan areas, whereas the secondary inorganic aerosols were strongly influenced by the long-range transport of air pollutants from Shandong and Jiangsu provinces in China.

The birthweight toll of mining pollution: evidence from the most contaminated mine site in the Andean region

OBJECTIVE

To assess the effect of mining pollution on birthweight.

DESIGN

A retrospective before-and-after study with an untreated comparison group.

SETTING

La Oroya, a mining town in the Peruvian Andes, considered the most contaminated town in the Andean region.

POPULATION

All pregnant women who delivered in the social security healthcare system in years 2005, 2006, 2008 and 2009. A total of 214 983 births records were used, 957 from La Oroya and 214 026 from the rest of the country.

METHODS

A difference-in-difference estimation is used to assess the effect of mining pollution on birthweight before and after two business policy changes: a partial environmental improvement and a subsequent closure of smelter operations in La Oroya. Birthweight was compared with a group not affected by the environmental changes in La Oroya.

MAIN OUTCOME MEASURES

Birthweight in grams.

RESULTS

A steep reduction in mining pollution due to the closure of smelter operations in La Oroya showed an increased birthweight of 71.6 g after controlling for socio-economic and medical characteristics. None of the environmental improvements prior to the closure had a statistically significant effect on birthweight.

CONCLUSIONS

Mining pollution in La Oroya had a negative impact on birthweight. Partial environmental improvements were not enough to improve birthweight. Only after the closure of all mining and smelter operations in La Oroya was a significant gain in birthweight shown.

TWEETABLE ABSTRACT

The closure of the most contaminated mine site in the Andean region increased birthweight by 72 g.

Lead Contamination and Source Characterization in Soils Around a Lead-Zinc Smelting Plant in a Near-Urban Environment in Baoji, China

Economic reforms in China since 1978 have promoted nationwide socioeconomic advancement but led to a considerable amount of environmental pollution. The distribution and sources of Pb in a typical peri-urban industrial part of Baoji, China, were assessed by determining the Pb contents and isotopic compositions in 52 topsoil samples from the study area. The topsoil samples were polluted averagely with 40.88 mg Pb kg^-1, was 1.86 times higher than the Pb content of local background soil (22.04 mg kg^-1). Pb isotopic compositions were determined by analyzing samples prepared using total digestion and acid extraction methods. Radiogenic isotopes contributed more to the Pb concentrations in the acid extracts than in the total digests. This was shown by the ^207/206Pb and ^208/206Pb ratios, which were 0.845-0.88 and 2.088-2.128, respectively, in the acid extracts and 0.841-0.875 and 2.086-2.125, respectively, in the total digests. This indicates that anthropogenic sources of Pb could be identified more sensitively in acid extracts than in total digests. The Pb isotope ratios showed that burning coal and smelting ore are the predominant anthropogenic sources of Pb in the study area, i.e., a lead-zinc smelter and a coking plant are major sources of Pb in the study area.

Effects of long-term irrigation with untreated municipal wastewater on soil properties and crop quality

Irrigating crops with untreated wastewater leads to elevated concentrations of heavy metals both in soil and cultivated crops. The current study was designed to determine heavy metal (i.e., Pb, Cd, Cr, Cu, Ni, Zn, Hg) accumulation in Konya soils in selected nine sites irrigated with wastewater for over 40 years. Non-irrigated soil samples and soil samples irrigated with well water were taken as control samples. Transport of these pollutants to the wheat samples cultivated in the investigated site was also examined. The obtained results reveal that high alkaline properties and clay structure of Konya soil reduce the mobility of contaminants and cause accumulation in the top layer of soil. Intense effect of wastewater irrigation on soil EC was determined. The highest concentrations of Pb, Cr, Cu, Cd, Zn, Ni, and Hg in wastewater irrigated soil were 5.32, 37.1, 31.5, 11.4, 91.5, 134, and 0.34 mg kg(-1), respectively. Wastewater irrigated soils were strongly polluted by means of Cd (8.23-11.6 mg kg(-1)) and moderately to strongly polluted by means of Ni (47.7-134 mg kg(-1)), exceeding Maximum Admissible Concentrations for Trace Elements in Agricultural Soils and Sewage Sludge Regulation limit values of Turkey. Maximum concentrations found for Pb, Cr, Cu, Cd, Zn, and Ni in wastewater irrigated wheat grain were 8.44, 1.30, 9.10, n.d, 29.31, and 0.94 mg kg(-1), respectively. Besides, Hg was not detected in any samples of wheat grain. Based on the regulation of Turkish Food Codex, Pb contamination in wheat samples grown in the sampling site was evidenced.

Evaluation of toxicological risk of foodstuffs contaminated with heavy metals in Swat, Pakistan

This study aimed to assess the concentrations of heavy metals such as cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in the available foodstuffs (crops, milk and water), their bioaccumulation in human body and potential human health risks in Swat valley, northern Pakistan. Heavy metal concentrations in foodstuffs and human blood (adults (18-above) and children (1-12 years)) were analyzed using atomic absorption spectrometer. The results revealed high level of Mn in foodstuffs followed by Cr>Cu>Zn>Ni>Cd>Pb, which significantly increased the levels of heavy metals in the adult׳s blood as compared to that of children in the order of Cr>Zn>Mn>Ni>Pb>Cu>Cd. Principal component analysis showed that selected foodstuffs were the possible sources of metal contamination in human blood, while correlation analysis revealed that the concentrations of Cr, Cu, Mn, Ni, Pb and Zn in foodstuffs significantly correlated with that in human blood. Moreover, risk assessments for individual metals via foodstuffs were found within safe limits, except for Cd (HQ>1); Whereas, for aggregate multiple metals the risk was calculated as 3.97E+00 (HI>1), in which water and milk were perceived as the greater contributors (81 percent) to HI; while fruits, grains and vegetables contributed 5 percent each, and pulses 4 percent.

Assessment of cadmium exposure for neonates in Guiyu, an electronic waste pollution site of China

This study aimed to determine the levels of placental cadmium (PCd) and cord blood cadmium (CBCd) and the resulting expression of placental metallothionein (MT) in neonates and to investigate cadmium (Cd) exposure levels in neonates and mothers who live in Guiyu, China, an electronic waste (e-waste) pollution site. Among the 423 mothers included in the study from 2004/2005 to 2007, 289 lived in Guiyu (exposed group) and 134 lived in Chaonan, located 10 km away from Guiyu (controls) and had never been exposed to e-waste pollution. CBCd and PCd levels were measured by atomic absorption spectrometry. Placental MT was examined by immunohistochemistry. Information on maternal and neonatal characteristics and exposure conditions was obtained from hospital records and by personal interviews. For the 3 years, the median CBCd was higher for Guiyu neonates than for controls (3.61 vs. 1.25 μg/L), with 25.61% of Guiyu subjects exhibiting a median CBCd that exceeded the safety limit defined by the World Health Organization (5 μg/L), as compared with 14.18% of control neonates (p < 0.01). In Guiyu, the mean PCd was higher than that for controls (0.17 ± 0.48 vs. 0.10 ± 0.11 μg/g, p ≤ 0.01). The high levels of CBCd and PCd were significantly associated with parents' occupational and environmental exposure to e-waste recycling pollutants. Staining for MT was positive and dense for 67.00% (67/100) of Guiyu neonates as compared with 32.69% (17/52) of controls (p < 0.01). Exposure to e-waste recycling pollutants increased Cd exposure in neonates, which was accompanied by increased placental MT expression.

Baden-Wuerttemberg Environmental Health Survey (BW-EHS) from 1996 to 2003: toxic metals in blood and urine of children

The environmental health surveillance system in the Federal State of Baden-Wuerttemberg (South Germany), among others, was implemented to monitor pollutant exposures and their temporal and regional trends in children at the age of about 10 years. The investigations were performed in two larger cities, one small city and one rural area. Between 1996 and 2003, in total 5470 children were investigated in consideration of environmental health parameters in four cross-sectional studies. The data presented here cover the results of the determination of the internal load with toxic metals. The median values observed in the investigation in 2002/03 were: 4.6 microg/l urine for arsenic, less than 0.2 microg/l urine for mercury, 20.7 microg/l blood for lead, and 0.25 microg/l blood for cadmium. From 1996 to 2003, mercury concentrations showed a substantial decrease (-0.027 microg/l/year) and lead levels also decreased (-0.25 microg/l/year), whereas arsenic and cadmium levels did not change significantly over time. There was no consistent difference in the mean internal load of the metals between the four investigation areas. Important factors influencing the measured concentrations were consumption of fish in the last 48 h, which had an impact on arsenic (factor 2), and amalgam fillings, which accounted for an increase in mercury (factor 4.6). In the 2002/03 study period, levels above the limit of health concern for children (German HBM values) were found in about 0.5% of the lead measurements (maximum value 180 microg/l blood) and in about 0.2% of the mercury measurements (maximum value 8.2 microg/l urine). In conclusion, this environmental health survey generates objective data on secular trends and regional differences and provides insight into probable sources of toxic metal exposure in children.

Occupational and environmental human lead exposure in Brazil

The purpose of this paper is to present a review of data on assessment of exposure and adverse effects due to environmental and occupational lead exposure in Brazil. Epidemiological investigations on children lead exposure around industrial and mining areas have shown that lead contamination is an actual source of concern. Lead in gasoline has been phasing out since the 1980s, and it is now completely discontinued. The last lead mining and lead refining plant was closed in 1995, leaving residual environmental lead contamination which has recently been investigated using a multidisciplinary approach. Moreover, there are hundreds of small battery recycling plants and secondary smelting facilities all over the country, which produce focal urban areas of lead contamination. Current regulatory limits for workplace lead exposure have shown to be inadequate as safety limits according to a few studies carried out lately.

Anthropometric, environmental, and dietary predictors of elevated blood cadmium levels in Ukrainian children: Ukraine ELSPAC group

No comprehensive data on sources or risk factors of cadmium exposure in Ukrainian children are available. In this we measured the blood levels of cadmium among 80 Ukrainian children and evaluated sources of exposure. A nested case-control study from a prospective cohort of Ukrainian 3-year-old children was conducted. We evaluated predictors of elevated blood cadmium using a multivariable logistic regression model. The model included socioeconomic data, parent occupation, environmental tobacco smoke, hygiene, body-mass index, and diet. Dietary habits were evaluated using the 1992 Block-NCI-HHHQ Dietary Food Frequency survey. Elevated cadmium was defined as blood levels in the upper quartile (0.25 microg/L). The mean age for all 80 children was 36.6 months. Geometric mean cadmium level was 0.21 microg/L (range = 0.11-0.42 microg/L; SD = 0.05). Blood cadmium levels were higher among children taking zinc supplements (0.25 vs 0.21 microg/L; P = 0.032), children who ate sausage more than once per week (0.23 vs 0.20; P = 0.007) and children whose fathers worked in a by-product coking industry (0.25 vs 0.21; P = 0.056). In the multivariable model, predictors of elevated blood cadmium levels included zinc supplementation (adjusted OR = 14.16; P < 0.01), father working in a by-product coking industry (adjusted OR = 8.50; P = 0.03), and low body mass index (<14.5; adjusted OR = 5.67; P = 0.03). This is the first study to indicate a strong association between elevated blood cadmium levels and zinc supplementation in young children. Whole-blood cadmium levels observed in this group of Ukrainian children appear to be similar to those reported in other Eastern European countries.

Environmental contamination of heavy metals from zinc smelting areas in Hezhang County, western Guizhou, China

Total heavy metal (Cd, Cr, Cu, Pb and Zn) concentrations were evaluated in smelting waste, soil, crop and moss samples collected from the Hezhang artisanal zinc smelting areas, Guizhou, China. Soil samples from the cornfield near the smelting sites contained extremely high Cd (5.8-74 mg kg(-1)), Pb (60-14,000 mg kg(-1)) and Zn (260-16,000 mg kg(-1)) concentrations. Elevated heavy metal concentrations were also found in corn plants and total Pb (0.80-1.5 mg kg(-1)) and Cd (0.05-0.76 mg kg(-1)) concentrations in corn grain have totally or partially exceeded the national guidance limits for foodstuff. Thus, the soil-to-crop transfer of heavy metals might pose a potential health risk to the local residents. Similar to the high heavy metal levels in soil and corn, Cd, Cr, Cu, Pb and Zn concentrations in moss samples collected from the smelting sites ranged from 10 to 110, 10 to 55, 26 to 51, 400 to 1200 and 330 to 1100 mg kg(-1), respectively, exhibiting a local spatial pattern of metals deposition from the atmosphere. Based on examination of Zn/Cd and Pb/Cd ratios of the analyzed samples, we have distinguished between the flue gas dust derived and smelting waste derived metals in different environmental compartments.

Effects of cadmium on Na+ transport in the isolated skin of the toad Pleurodema thaul

Cadmium ions applied to either (outer or inner) surface of the isolated toad skin dose-dependently increased the short-circuit current (SCC), the potential difference (V) and the active sodium conductance (G(Na)) in the concentration range 0.07-0.50mM. Maximal stimulatory effect was over 30% with an EC(50) of about 0.1mM. The effect of the highest concentration used (0.75mM) decreased considerably, and when it was applied to the inner surface (10 experiments), induced between 30% and 40% inhibition of the electric parameters in four experiments. Pretreatment with amiloride inverted the stimulatory effect of externally applied Cd(2+), suggesting competitive action on the apical Na(+) channel. The effect of noradrenaline (NA) was increased after outer application of Cd(2+) and decreased after inner application of the metal: the latter effect might be due to cadmium inhibition of the activity of Na(+),K(+)-ATPase. On the other hand, pretreatment with amiloride was followed by partial although transient reversal of its effects by serosal Cd(2+), which might be explained by action of cadmium on cytoplasmic lysine residues concerned with Na(+) channel gating. The amiloride test showed that the increment of the electric parameters was due principally to stimulation of the driving potential for Na(+) (V-E(Na(+))) and that inhibition was accompanied by a reduction in the V-E(Na(+)) and by a significant decrease in skin resistance indicating possible disruption of membrane or cell integrity. These data are in favor of the possibility that externally applied Cd(2+) activates toad skin ion transport, partly by increasing apical sodium conductance and also by stimulating the V-E(Na(+)), and that internally applied Cd(2+), with easier access to membrane and cellular constituents, may inhibit the sodium pump.

Predictors of elevated blood lead levels among 3-year-old Ukrainian children: a nested case-control study

OBJECTIVES

Lead is common in the general population. However, data are lacking for the Ukraine and many other countries from the former Soviet Union (FSU). In this study we evaluate the level of blood lead among 212 Ukrainian children and determine predictors of elevated lead levels. We also describe the health effects associated with elevated blood lead.

METHODS

A nested case-control study from a prospective cohort of Ukrainian 3-year-old children was conducted in March 1998. Blood assays were analyzed for lead by labs at the Centers for Disease Control and using portable examination kits. We evaluated predictors of elevated blood lead (blood levels in the upper quartile >4.65 microg/dL) using a multivariable logistic regression model. The model included socioeconomic status, parent occupation, environmental tobacco smoke, hygiene, diet, and health status.

RESULTS

The geometric mean lead level was 3.15 microg/dL (range, 0.7--22.7). In our adjusted model, we observed a strong association between lead levels in the upper quartile and children whose fathers worked manual labor jobs in industries associated with lead exposures [adjusted odds ratio (OR)=2.25; P=0.025] and mothers who smoke indoors (adjusted OR=2.87; P=0.047). Daily hygiene and dietary habits were not associated with elevated lead levels. No increased risks of overall morbidity or lead-associated illness were observed (anemia, dental caries, renal disease, cardiovascular diseases, and musculoskeletal complaints).

CONCLUSION

This is the first study to describe lead levels and associated variables among Ukrainian children in the peer-reviewed literature. Elevated lead levels in these children were associated with paternal occupation and mothers smoking indoors. At age 3 no adverse health effects were observed. More data are needed to determine the level of heavy metal contamination in children from the Ukraine and many other former Soviet nation-states.

Isotopic characterisation of lead in contaminated soils from the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria

Soil samples from the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria contained very high concentrations of cadmium, lead and zinc (up to 140, 4900 and 5900 mg kg(-1), respectively). A roadside soil in a relatively uncontaminated area also contained high concentrations of the same metals (24, 1550 and 1870 mg kg(-1), respectively) indicating that the transport of ores could be a source of contamination. Even though the lead isotope ratios in all the samples fell within a very narrow range (for example, 1.186-1.195 for (206)Pb/(207)Pb), the samples could be differentiated into three distinct groups: ores ((206)Pb/(207)Pb and (208)Pb/(207)Pb ratios of 1.1874-1.1884 and 2.4755-2.4807, respectively), current deposition (1.1864 and 2.4704-2.4711, respectively) and local background (1.1927-1.1951 and 2.4772-2.4809, respectively). Although most of the current deposition has its origin in the ores used at the smelter, up to 12% could be from other sources such as petrol lead.

Micronuclei in peripheral blood lymphocytes of workers exposed to lead

Lead plays an important role in many industrial processes. Although highly useful to man, lead has various types of toxic effects. There is constantly growing evidence of a relationship between the induction of chromosome breaks and an increased risk of onset of cancer. However, available data about the possible genotoxic and carcinogenic action of lead are conflicting. In this report we present the results of studies on lead concentrations in blood and the respective micronucleus frequencies in peripheral blood lymphocytes from workers employed in the recycling of automotive batteries in the surroundings of Porto Alegre, Brazil. We observed that in the occupationally exposed group, both lead concentration in peripheral blood and micronucleus frequency in lymphocytes were significantly higher compared to control (Z=6.35, P<0.0001 and Z=4.47, P<0.0001). The nuclear division index (NDI) values were significantly higher in the control group than in the exposed group (Z=2.13, P=0.0330), indicating a possible effect of Pb on nuclear proliferation. We also detected a negative correlation between micronuclei and progression of nuclear division (tau=-0.312, P=0.0129). There were no changes in micronucleus frequency between smoking and non-smoking workers exposed to lead (Z=0.03, P=0.9790). The only difference found between the groups of smokers and non-smokers was with respect to NDI, whose values were significantly higher among non-smokers (Z=1.98, P=0.0481).