Contamination and health risks brought by arsenic, lead and cadmium in a water-soil-plant system nearby a non-ferrous metal mining area.

Heavy metal(loid)s contamination prevails in the water-soil-plant system around non-ferrous metal mining areas. The present study aimed to evaluate the heavy metal(loid)s contamination in Nandan Pb-Zn mining area (Guangxi, China). A total of 36 river water samples, 75 paired paddy soil and rice samples, and 128 paired upland soil and plant samples were collected from this area. The concentrations of arsenic (As), lead (Pb), and cadmium (Cd) in these samples were measured. Results showed that the average water quality indexes (WQIs) at the 12 sampling sites along the main river ranged from 41 to 5008, indicating the water qualities decreasing from "Excellent" to "Undrinkable". The WQIs nearby tailings or industrial park were significantly higher than those at the other sites. 34.0% and 64.5% of soil samples exceeded the risk screening values for As and Cd. The Pb and Cd concentrations in all rice samples exceeded the Chinese food safety limits by 18.7% and 82.7%, respectively. Leafy vegetables had a higher concentration of As, Pb, and Cd than other vegetables, exceeding the maximum permissible limits by 14.1%, 61.2%, and 40.0%, respectively. The biological accumulation coefficient (BAC) of Cd was the highest in rice and lettuce leaves. The hazard quotients (HQs) of As and Cd, indicating non-carcinogenic risks, were 4.15 and 1.76 in adult males, and 3.40 and 1.45 in adult females, all higher than the permitted level (1.0). The carcinogenic probabilities of As and Cd from rice and leafy vegetables consumption were all higher than 1 × 10-4. We conclude that metal(loid)s contamination of the water-soil-plant system has posed great non-carcinogenic and carcinogenic risks to the local population.

Association of lead and cadmium exposure with kidney stone incidence: A study on the non-occupational population in Nandan of China.

BACKGROUND: Environmental lead (Pb) and cadmium (Cd) pollution has been considered a risk factor in the etiology of kidney stones. However, the association between Pb and Cd exposure and kidney stone incidence has yet to be determined. OBJECTIVES: This study aimed to determine a possible the association between kidney stones with Pb and Cd exposure (alone or combined) in a non-occupational population. METHODS: Pb and Cd contaminations in soil-plant system were determined by flame atomic absorption spectrophotometry. Health risk assessment of dietary Pb or Cd intake from rice and vegetables were calculated. Kidney stones were diagnosed with urinary tract ultrasonography. Urinary cadmium (UCd) and blood lead (BPb) levels were determined by graphite-furnace atomic absorption spectrometry. Multivariate logistic regression models were constructed. RESULTS: The hazard indexes (HI) of Pb and Cd were 7.91 and 7.31. The odds ratio (OR) was 2.83 (95 %CI:1.38-5.77) in males with high BPb (BPb ≥ 100 µg/L), compared with those with low BPb (BPb＜100 µg/L). Compared to those with low BPb and low UCd (BPb＜100 µg/L and UCd＜2 µg/g creatinine), the ORs were 2.58 (95 % CI:1.17-5.70) and 3.43 (95 % CI:1.21-9.16) in females and males with high BPb and high UCd (BPb ≥100 µg/L and UCd ≥2 µg/g creatinine), respectively. The OR was 3.16 (95 % CI:1.26-7.88) in males with high BPb and low UCd (BPb ≥ 100 µg/L and UCd ＜2 µg/g creatinine), compared to those with low BPb and low UCd. CONCLUSIONS: Kidney stones incidence was increased by high Pb exposure in males, and by Pb and Cd co-exposure in males and females.

Cause analysis of PM2.5 pollution during the COVID-19 lockdown in Nanning, China.

To analyse the cause of the atmospheric PM2.5 pollution that occurred during the COVID-19 lockdown in Nanning, Guangxi, China, a single particulate aerosol mass spectrometer, aethalometer, and particulate Lidar coupled with monitoring near-surface gaseous pollutants, meteorological conditions, remote fire spot sensing by satellite and backward trajectory models were utilized during 18-24 February 2020. Three haze stages were identified: the pre-pollution period (PPP), pollution accumulation period (PAP) and pollution dissipation period (PDP). The dominant source of PM2.5 in the PPP was biomass burning (BB) (40.4%), followed by secondary inorganic sources (28.1%) and motor vehicle exhaust (11.7%). The PAP was characterized by a large abundance of secondary inorganic sources, which contributed 56.1% of the total PM2.5 concentration, followed by BB (17.4%). The absorption Ångström exponent (2.2) in the PPP was higher than that in the other two periods. Analysis of fire spots monitored by remote satellite sensing indicated that open BB in regions around Nanning City could be one of the main factors. A planetary boundary layer-relative humidity-secondary particle matter-particulate matter positive feedback mechanism was employed to elucidate the atmospheric processes in this study. This study highlights the importance of understanding the role of BB, secondary inorganic sources and meteorology in air pollution formation and calls for policies for emission control strategies.

Highly time-resolved aerosol characteristics during springtime in Weizhou Island.

A single particle aerosol mass spectrometer was deployed to measure the changes of single particle species and sizes during March 2015 in Weizhou Island of the Beibu Gulf, Guangxi province, South China. In this campaign, a total of 3,100,597 particles were sized, and 25.8% particles with both positive and negative mass spectrum were collected and 24.8% characterized in combination with the ART-2a neural network algorithm. The distribution of sized particles was mainly in from 520 to 600nm, and the diameters ranging from 340 to 1000nm accounted for above 90%. Eight types of particles were classified: Elemental Carbon containing (EC), Organic Carbon containing (OC), EC and OC combined containing particles, Na containing particles, K containing particles (K), Levoglucosan containing particles, mineral containing particles, and Heavy Metal containing particles (HM). EC, OC and K were the major containing particles, which accounted for 84.3% in the eight types particles. The relative ratio and size distribution of the three types were EC (48.1%, 620nm), OC (12.7%, 440nm), and K (23.5%, 600nm), respectively. The three types of particles were a bit increasing ratios compared with those in clean periods during haze pollution periods. Combined with the back-trajectory results from the Hysplit-4 model and local pollution sources revealed that the ambient air quality on the Weizhou Island may be influenced by biomass burning in the Indochina Peninsula (biomass burning in the Indochina Peninsula) from the transportation on higher level atmospheric layer and by mainland of south China located northeast of Weizhou Island on the ground.

[Characteristics of Organic and Elemental Carbon in PM10 and PM2.5 in Yulin City, Guangxi].

Two hundred eighteen PM10 and 202 PM2.5 samples were collected at three sampling sites to study the pollution characteristics of carbonaceous aerosols in Yulin from July 2015 to March 2016. Organic carbon (OC) and elemental carbon (EC) in the PM10 and PM2.5 samples were analyzed by a Multiwavelength Thermal/Optical Carbon Analyzer, and the characteristics, including pollution levels, temporal and spatial distributions, and possible sources of OC and EC, were investigated. The results showed that the OC and EC mass concentrations in PM10 in Yulin were 10.99 and 5.11 µg·m-3, respectively, while the OC and EC mass concentrations in PM2.5 were 7.51 and 4.70 µg·m-3, respectively. Strong correlations between OC and EC were found in PM10(R2=0.58) and PM2.5(R2=0.60). The winter average concentrations of secondary organic carbon (SOC) in PM10 and PM2.5 were 14.50 µg·m-3 and 6.74 µg·m-3, respectively. The SOC/OC ratios in both the PM10 and PM2.5 were higher than 0.5. The contribution of SOC to OC was 80.6% in PM10 and 77.7% in PM2.5, which were the highest in the summer, in accordance with the high temperature and strong solar radiation in the summer.

[Physiochemical Properties and Sources of Atmospheric Particulate Matter During Pollution Monitoring in Nanning, China].

Distribution characteristics, chemical constituents, and sources of particulate matter were measured using a scanning mobility particle sizer and single particle aerosol mass spectrometer during pollution monitoring that occurred between December 5th and December 11th, 2016, in Nanning. Results showed that particulate matter (PM) sized between 20 nm-10 µm were concentrated in the 23 to 395 nm range, with a peak of 100 nm. Three new particle types were generated during the course of this monitoring. These new 30 nm particles came into existence between 14:00 to 18:00, and grew to a size of between 40 nm and 110 nm between 20:00 to 06:00 the next day. The generation of the all three new particles was affected by motor vehicle exhaust emissions. Many secondary particles were also produced during this period of pollution. The source of the fine particulate matter was mainly from the burning of biomass, dust, and the combustion of coal. In addition, a long-distance transmission also contributed to the particles from biomass burning.

[Analysis of Chemical Composition and Pollution Source of the Fine Particulate Matter by the SPAMS in the Four Seasons in Nanning].

To study the chemical composition and pollution sources of the fine particulate matter during the four seasons in Nanning, single particle aerosol mass spectrometry was performed to characterize the fine particulate matter in Nanning during the four seasons. The correlation (R2) between the fine particulate matter number concentration and the mass concentration of the fine particulate matter obtained using SPAMS was all above 0.75 in the observation period. The particle number concentration could reflect the atmospheric pollution situation to some degree. The average mass spectrogram of the fine particulate matter reflected that secondary pollutants were more in winter and spring in Nanning. The Art-2a classification method was used to classify the chemical composition of the fine particulate matter. The results showed that the number concentration of the chemical composition and sources of pollution had differences in the four seasons. Chemical composition could reflect pollution sources. The elevated elemental carbon was positively with increasing coal combustion in winter. The elevated organic carbon was positively correlated with motor vehicle source in autumn. Rich potassium particles, levoglucosan and substance were positively correlated with biomass burning source and dust in summer. The rich sodium particles and heavy metals were higher in spring. During the process of increasing pollution, the contributions of biomass and coal combustion sources were large.

Oxidative Stress and Genotoxicity of Long-Term Occupational Exposure to Low Levels of BTEX in Gas Station Workers.

Atmospheric benzene, toluene, ethylbenzene, and xylenes (BTEX) can lead to multiple health injuries. However, what remains uncertain is the effect of long-term exposure to low levels of BTEX. Thus, we determined the BTEX levels in the air from the refueling and office areas in gas stations. Then we collected workers' (200 refueling vs. 52 office workers) peripheral blood samples to analyze the serum total-superoxide dismutase (T-SOD), glutathione (GSH), malondialdehyde (MDA), and 8-hydroxydeoxyguanosine (8-OHdG) levels. DNA damage was analyzed by the comet assay and micronucleus test in buccal epithelial cells. We found that the levels of BTEX in refueling areas were significantly higher than those in office areas (p < 0.001). The serum T-SOD and GSH of refueling workers were significantly lower than those in office workers (p < 0.001). By contrast, the serum MDA and 8-OHdG of refueling workers were significantly higher than those of office workers (p < 0.001, MDA; p = 0.025, 8-OHdG). Furthermore, tail and Olive tail moments in refueling workers were longer (p = 0.004, tail moment; p = 0.001, Olive tail moment), and the micronucleus rate was higher (p < 0.001) than those in office workers. Taken together, long-term exposure to low levels of BTEX may reduce the antioxidant ability and increase the risk of DNA damage in refueling workers of gas stations.

[Chemical Composition of the Single Particle Aerosol in Winter in Nanning Using SPAMS].

Single Particle Aerosol Mass Spectrometry (SPAMS) was performed to characterize the PM2.5 in Nanning from 15 to 24 February 2015. The correlation (R2) between the PM2.5 number concentration and the mass concentration of PM2.5 obtained using SPAMS was 0.76. The particle number concentration could reflect the atmospheric pollution situation to some degree. The Art-2a classification method was used to classify the chemical composition of PM2.5. The results showed that the principal chemical constituents were elemental carbon, organic elements carbon hybrid particles, organic carbon, rich potassium particles, mineral substance, rich sodium particles, second inorganic particles, levoglucosan and other heavy metals. Among them, the composition of elemental carbon was the highest, followed by organic carbon and rich potassium particles. The particle size of 80% of PM2.5 was mainly concentrated in the range of 0.2 microm to 1.0 microm with a peak value occurring at 0. 62 microm. The particle size distribution characteristics of different chemical components were similar. The number concentration of the chemical components in PM2.5 had the same variation tread with the mass concentration of PM2.5 over time. To a certain extent, the change in chemical composition could reflect the instantaneous pollution source.

Concentrations and potential health risks of methyl tertiary-butyl ether (MTBE) in air and drinking water from Nanning, South China.

Levels of methyl tertiary-butyl ether (MTBE) in occupational air, ambient air, and drinking water in Nanning, South China, were investigated, and then their potential health risks to occupational workers and the general public were evaluated. Results show that the MTBE concentration in occupational air from 13 service stations was significantly higher than that in ambient air from residential areas (p<0.0001); both are far lower than the threshold limit value-time weighted average of MTBE regulated in the United States (US). The drinking water samples from household taps yielded detectable MTBE in the range of 0.04-0.33 µg/L, which is below the US drinking water standard of 20-40 µg/L. The non-carcinogenic risk of MTBE from air inhalation may be negligible because the calculated hazard quotient was less than 1. The mean MTBE lifetime cancer risk was within the acceptable limit of 1 × 10(-6) to 1 × 10(-4), but the lifetime cancer risk of refueling workers in the urban service station at the 95th percentile slightly exceeded the maximum acceptable carcinogen risk (1 × 10(-4)), indicating the potential carcinogenic health effects on the population highly exposed to MTBE in this region. The hazard index and carcinogenic risk of MTBE in drinking water were significantly lower than the safe limit of US Environmental Protection Agency, suggesting that drinking water unlikely poses significant health risks to the residents in Nanning.

p53-Dependent apoptosis induced in human bronchial epithelial (16-HBE) cells by PM(2.5) sampled from air in Guangzhou, China.

Epidemiological studies have shown that air pollution particulate matter (PM) is associated with increased respiratory morbidity and mortality. However, the mechanisms are not fully understood. Oxidative stress-mediated apoptosis plays an important role in the occurrence of respiratory diseases. In this study, human bronchial epithelial (16-HBE) cells were exposed to different concentrations (16-128 µg/ml) of PM(2.5) for 24 h to investigate the apoptosis induced by PM(2.5). The results showed that PM(2.5) exposure significantly induced apoptosis, DNA strand breaks, and oxidative damage in a dose-dependent manner in 16-HBE cells. The expression of p53 and p73 increased significantly along with the dose of PM(2.5) in 16-HBE cells, whereas the expression of p21(Cip1/WAF1) decreased; the expression of mdm2 increased and then decreased, but not significantly. Taken together, these observations indicate that PM(2.5) may lead to oxidative damage and induce apoptosis through the p53-dependent pathway in 16-HBE cells. p53-Dependent apoptosis mediated by DNA strand breaks may be an important mechanism of PM(2.5)-induced apoptosis in 16-HBE cells.

Association between exposure to electromagnetic fields from high voltage transmission lines and neurobehavioral function in children.

BACKGROUND: Evidence for a possible causal relationship between exposure to electromagnetic fields (EMF) emitted by high voltage transmission (HVT) lines and neurobehavioral dysfunction in children is insufficient. The present study aims to investigate the association between EMF exposure from HVT lines and neurobehavioral function in children. METHODS: Two primary schools were chosen based on monitoring data of ambient electromagnetic radiation. A cross-sectional study with 437 children (9 to 13 years old) was conducted. Exposure to EMF from HVT lines was monitored at each school. Information was collected on possible confounders and relevant exposure predictors using standardized questionnaires. Neurobehavioral function in children was evaluated using established computerized neurobehavioral tests. Data was analyzed using multivariable regression models adjusted for relevant confounders. RESULTS: After controlling for potential confounding factors, multivariable regression revealed that children attending a school near 500 kV HVT lines had poorer performance on the computerized neurobehavioral tests for Visual Retention and Pursuit Aiming compared to children attending a school that was not in close proximity to HVT lines. CONCLUSIONS: The results suggest long-term low-level exposure to EMF from HVT lines might have a negative impact on neurobehavioral function in children. However, because of differences in results only for two of four tests achieved statistical significance and potential limitations, more studies are needed to explore the effects of exposure to extremely low frequency EMF on neurobehavioral function and development in children.