SEGH Articles

Chronic cadmium exposure promotes nasopharyngeal carcinoma progression and radioresistance

24 January 2019
Dr Lin Peng and her team investigate how environmental pollutant exposure influences the risk of cancer development and therapeutic resistance at the Clinical Laboratory, Cancer Hospital of Shantou University Medical College, China.

Dr Lin Peng, Associate Chief Physician, works in Clinical Laboratory, Cancer Hospital of Shantou University Medical College in China. The research team she leads focuses on environmental pollutant exposure and the risk of cancer development and therapeutic resistance. Her team has recently published research results highlighting the association between cadmium and breast cancer, connecting gastrointestinal cancer risk to cadmium and lead exposure and the association of polychlorinated biphenyls/polybrominated diphenyl ethers with breast cancer risk.

Lin Peng analysing blood samples

Lin Peng analysing blood samples

Nasopharyngeal carcinoma (NPC) is a unique malignancy with a high prevalence in East and Southeast Asia, especially in southern China. The unique ethnic and geographical distribution of NPC indicates hereditary factor and environmental factors may contribute to its unusual etiology. But to date, only nitrosamine, polycyclic aromatic hydrocarbons and nickel are regarded as environmental risk factors in the development and progression of NPC. Cadmium is a ubiquitous carcinogenic pollutant related with some human cancers. The aim of the present study was to evaluate the association between chronic low-concentration cadmium exposure and NPC progression and radiosensitivity.

Hospital-based 134 NPC cases and 132 cancer-free controls were recruited, the blood cadmium levels of whom were detected by graphite furnace atomizer absorption spectrophotometer and the basic clinical data and demographic characteristics were collected. To further confirm the effect of cadmium on NPC progression and radiosensitivity in vitro and in vivo, NPC cell lines CNE-1 and CNE-2 were continuously exposed with 1 μM cadmium chloride for 10 weeks. MTT assay, colony formation assay and xenograft tumor growth were used to assess cell viability and radiosensitivity. Transwell assays were performed to detect cell invasion and migration. The median concentration of blood cadmium in cases (3.84, IQR 2.21–6.10) was found significantly higher than that of controls (2.28, IQR 1.79–3.45) (P<0.001). Meanwhile, blood cadmium levels were positively associated with clinical stages and N classification (r=0.193, 0.187, respectively, P<0.05). MTT assay and colony formation assays showed that the cell proliferation in cadmium exposed NPC cells was significantly increased compared to the parental cells (P<0.05). Also, the invasive and migrative capacity of cadmium-treated NPC cells was markedly increased over 1.40-(P<0.01) and 1.30-(P<0.01) fold of the controls, respectively. In particular, xenograft tumours with cadmium-treated NPC cells exhibited increased tumour growth and radioresistance compared to transplanted controls(P<0.05). These results reveal the stimulative effect of chronic low-dose cadmium exposure on malignant progression and radioresistance of NPC for the first time.

 Lin Peng at the 34th International Conference of SEGH in Livingstone, Zambia

Lin Peng at the 34th SEGH International Conference in Livingstone, Zambia


 Lin Peng1,2,, Yi-Teng Huang3, Jiong-Yu Chen4*, Xia Huo5*

1 Clinical Laboratory, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou 515041, PR China.

2 Laboratory of Environmental Medicine and Developmental Toxicology, Shantou University Medical College, No. 22 Xinling Road, Shantou 515041, PR China.

3 Health Care Center, The First Affiliated Hospital of Shantou University Medical College, Shantou 515041, PR China.

4 Oncological Research Lab, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou 515031, PR China.

5 Laboratory of Environmental Medicine and Developmental Toxicology, Guangzhou and Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, 601 Huangpu Avenue West, Guangzhou 510632, PR, China

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Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

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    Abstract

    This study investigated the effects and fate of the antibiotic ciprofloxacin (CIP) at environmentally relevant levels (50–500 µg/L) in activated sludge (AS) microbial communities under aerobic conditions. Exposure to 500 µg/L of CIP decreased species diversity by about 20% and significantly altered the phylogenetic structure of AS communities compared to those of control communities (no CIP exposure), while there were no significant changes upon exposure to 50 µg/L of CIP. Analysis of community composition revealed that exposure to 500 µg/L of CIP significantly reduced the relative abundance of Rhodobacteraceae and Nakamurellaceae by more than tenfold. These species frequently occur in AS communities across many full-scale wastewater treatment plants and are involved in key ecosystem functions (i.e., organic matter and nitrogen removal). Our analyses showed that 50–500 µg/L CIP was poorly removed in AS (about 20% removal), implying that the majority of CIP from AS processes may be released with either their effluents or waste sludge. We therefore strongly recommend further research on CIP residuals and/or post-treatment processes (e.g., anaerobic digestion) for waste streams that may cause ecological risks in receiving water bodies.

  • Source and background threshold values of potentially toxic elements in soils by multivariate statistics and GIS-based mapping: a high density sampling survey in the Parauapebas basin, Brazilian Amazon 2019-08-10

    Abstract

    A high-density regional-scale soil geochemical survey comprising 727 samples (one sample per each 5 × 5 km grid) was carried out in the Parauapebas sub-basin of the Brazilian Amazonia, under the Itacaiúnas Basin Geochemical Mapping and Background Project. Samples were taken from two depths at each site: surface soil, 0–20 cm and deep soil, 30–50 cm. The ground and sieved (< 75 µm) fraction was digested using aqua regia and analyzed for 51 elements by inductively coupled plasma mass spectrometry (ICPMS). All data were used here, but the principal focus was on the potential toxic elements (PTEs) and Fe and Mn to evaluate the spatial distribution patterns and to establish their geochemical background concentrations in soils. Geochemical maps as well as principal component analysis (PCA) show that the distribution patterns of the elements are very similar between surface and deep soils. The PCA, applied on clr-transformed data, identified four major associations: Fe–Ti–V–Sc–Cu–Cr–Ni (Gp-1); Zr–Hf–U–Nb–Th–Al–P–Mo–Ga (Gp-2); K–Na–Ca–Mg–Ba–Rb–Sr (Gp-3); and La–Ce–Co–Mn–Y–Zn–Cd (Gp-4). Moreover, the distribution patterns of elements varied significantly among the three major geological domains. The whole data indicate a strong imprint of local geological setting in the geochemical associations and point to a dominant geogenic origin for the analyzed elements. Copper and Fe in Gp-1 were enriched in the Carajás basin and are associated with metavolcanic rocks and banded-iron formations, respectively. However, the spatial distribution of Cu is also highly influenced by two hydrothermal mineralized copper belts. Ni–Cr in Gp-1 are highly correlated and spatially associated with mafic and ultramafic units. The Gp-2 is partially composed of high field strength elements (Zr, Hf, Nb, U, Th) that could be linked to occurrences of A-type Neoarchean granites. The Gp-3 elements are mobile elements which are commonly found in feldspars and other rock-forming minerals being liberated by chemical weathering. The background threshold values (BTV) were estimated separately for surface and deep soils using different methods. The ‘75th percentile’, which commonly used for the estimation of the quality reference values (QRVs) following the Brazilian regulation, gave more restrictive or conservative (low) BTVs, while the ‘MMAD’ was more realistic to define high BTVs that can better represent the so-called mineralized/normal background. Compared with CONAMA Resolution (No. 420/2009), the conservative BTVs of most of the toxic elements were below the prevention limits (PV), except Cu, but when the high BTVs are considered, Cu, Co, Cr and Ni exceeded the PV limits. The degree of contamination (Cdeg), based on the conservative BTVs, indicates low contamination, except in the Carajás basin, which shows many anomalies and had high contamination mainly from Cu, Cr and Ni, but this is similar between surface and deep soils indicating that the observed high anomalies are strictly related to geogenic control. This is supported when the Cdeg is calculated using the high BTVs, which indicates low contamination. This suggests that the use of only conservative BTVs for the entire region might overestimate the significance of anthropogenic contamination; thus, we suggest the use of high BTVs for effective assessment of soil contamination in this region. The methodology and results of this study may help developing strategies for geochemical mapping in other Carajás soils or in other Amazonian soils with similar characteristics.

  • Uptake of Cd, Pb, and Ni by Origanum syriacum produced in Lebanon 2019-08-06

    Abstract

    Trace metals are found naturally in soil. However, the increase in industrial and agricultural polluting activities has increased trace metal contamination and raised high concerns in the public health sector. The study was conducted on Origanum syriacum, one of the most consumed herbs in the Middle East, and was divided into three parts. (1) Pot experiment: to study the effect of Cd, Pb, or Ni levels in soil on their uptake by O. syriacum. (2) Field samples: collected from major agricultural regions in Lebanon to analyze Cd, Pb, and Ni concentrations in soil and leaves. (3) Sale outlets samples: to measure the levels of Cd, Pb, and Ni in O. syriacum tissues in the market. Results showed that there was a positive correlation between levels of Cd, Pb, and Ni in soil and those in O. syriacum tissues. None of the field samples contained Pb or Ni that exceeded the maximum allowable limits (MAL). Three samples collected from heavily poultry-manured soil contained Cd higher than the MAL. Samples collected from sale outlets did not exceed the MAL for Ni but two exceeded the MAL for Cd and one for Pb. Trace metal contamination is not a major concern in O. syriacum produced in Lebanon. Only one mixture sample from a sale outlet was higher in Pb than the MAL and three samples from heavily manured fields exceeded the MAL for Cd.