Trace element and stable isotope analyses of deep sea fish from the Sulu sea, Philippines

Thirty-five deep sea fishes belonging to 22 species and one unidentified specimen obtained from the Sulu Sea, located in the southwestern area of the Philippines were analyzed in the late 2002, for 23 trace elements using ICP-MS, HGAAS and CV-AAS. Predominant accumulation of strontium (Sr) was observed in all the samples. This stems from the fact that the whole body of fish was homogenized since Sr is known to accumulate in bones and hard tissues. Mercury concentrations in all the 36 samples were below the detection limit. Cadmium concentrations were generally below 1ìg/g dry weight (dw) except in Pterygotrigla spp. (4.29 ìg/g dw) and Sternoptyx pseudodiaphana (2.89 ìg/g dw). Concentrations of Pb were predominantly low with about 90% of the specimens having less than 1 ìg/g dw. In general, concentrations of Sr, Zn, Cu, Se and Cd appeared to increase with increasing depth of occurrence of the species.Manganese, Tl, Pb, Bi, In, Cs and As showed significant positive correlation (p < 0.05) with d15N, suggesting that these elements were biomagnified. To our knowledge, this is the first study reporting Tl biomagnification in fish. Rubidium and Cs showed significant positive correlation with d13C, implying that Rb and Cs would originate from offshore waters as oceanic plankton has high d13C. Comparing results from this study to the dietary standards and guidelines for Hg, Pb, Cu and Zn in fish and shellfish of the Ministry of Agriculture, Fisheries and Food of the United Kingdom,these levels were not high to warrant concern if they were to be consumed by humans. However, 16.7% of the fish samples had high Cr levels when compared with the Hong Kong’s safe limit of 4 ìg/g dw for Cr in sea food. This constitutes a health risk to humans, as Cr is potentially toxic

Arsenic contamination in groundwater and residents from Ha Nam and Ha Tay Provinces of Red River Delta, Vietnam

Joint Research on Environmental Science and Technology for the Eart

Genome wide association mapping of grain arsenic, copper, molybdenum and zinc in rice (Oryza sativa L.) grown at four international field sites

Peer reviewedPublisher PD

Genome-Wide Association Study Identifies Chromosome 10q24.32 Variants Associated with Arsenic Metabolism and Toxicity Phenotypes in Bangladesh

Arsenic contamination of drinking water is a major public health issue in many countries, increasing risk for a wide array of diseases, including cancer. There is inter-individual variation in arsenic metabolism efficiency and susceptibility to arsenic toxicity; however, the basis of this variation is not well understood. Here, we have performed the first genome-wide association study (GWAS) of arsenic-related metabolism and toxicity phenotypes to improve our understanding of the mechanisms by which arsenic affects health. Using data on urinary arsenic metabolite concentrations and approximately 300,000 genome-wide single nucleotide polymorphisms (SNPs) for 1,313 arsenic-exposed Bangladeshi individuals, we identified genome-wide significant association signals (P<5×10−8) for percentages of both monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) near the AS3MT gene (arsenite methyltransferase; 10q24.32), with five genetic variants showing independent associations. In a follow-up analysis of 1,085 individuals with arsenic-induced premalignant skin lesions (the classical sign of arsenic toxicity) and 1,794 controls, we show that one of these five variants (rs9527) is also associated with skin lesion risk (P = 0.0005). Using a subset of individuals with prospectively measured arsenic (n = 769), we show that rs9527 interacts with arsenic to influence incident skin lesion risk (P = 0.01). Expression quantitative trait locus (eQTL) analyses of genome-wide expression data from 950 individual's lymphocyte RNA suggest that several of our lead SNPs represent cis-eQTLs for AS3MT (P = 10−12) and neighboring gene C10orf32 (P = 10−44), which are involved in C10orf32-AS3MT read-through transcription. This is the largest and most comprehensive genomic investigation of arsenic metabolism and toxicity to date, the only GWAS of any arsenic-related trait, and the first study to implicate 10q24.32 variants in both arsenic metabolism and arsenical skin lesion risk. The observed patterns of associations suggest that MMA% and DMA% have distinct genetic determinants and support the hypothesis that DMA is the less toxic of these two methylated arsenic species. These results have potential translational implications for the prevention and treatment of arsenic-associated toxicities worldwide

Barium Promotes Anchorage-Independent Growth and Invasion of Human HaCaT Keratinocytes via Activation of c-SRC Kinase

Explosive increases in skin cancers have been reported in more than 36 million patients with arsenicosis caused by drinking arsenic-polluted well water. This study and previous studies showed high levels of barium as well as arsenic in the well water. However, there have been no reports showing a correlation between barium and cancer. In this study, we examined whether barium (BaCl2) may independently have cancer-related effects on human precancerous keratinocytes (HaCaT). Barium (5–50 µM) biologically promoted anchorage-independent growth and invasion of HaCaT cells in vitro. Barium (5 µM) biochemically enhanced activities of c-SRC, FAK, ERK and MT1-MMP molecules, which regulate anchorage-independent growth and/or invasion. A SRC kinase specific inhibitor, protein phosphatase 2 (PP2), blocked barium-mediated promotion of anchorage-independent growth and invasion with decreased c-SRC kinase activity. Barium (2.5–5 µM) also promoted anchorage-independent growth and invasion of fibroblasts (NIH3T3) and immortalized nontumorigenic melanocytes (melan-a), but not transformed cutaneous squamous cell carcinoma (HSC5 and A431) and malignant melanoma (Mel-ret) cells, with activation of c-SRC kinase. Taken together, our biological and biochemical findings newly suggest that the levels of barium shown in drinking well water independently has the cancer-promoting effects on precancerous keratinocytes, fibroblast and melanocytes in vitro