Prevalence of arsenic exposure in population of Ballia district from drinking water and its correlation with blood arsenic level.

An investigation was carried out to ascertain the effect of arsenic in the blocks of Ballia district in Uttar Pradesh in the upper and middle Ganga plain, India. Analysis of 100 drinking water samples revealed that arsenic concentration was below 10 µg l⁻¹ in 60% samples, 10-50 µg l⁻¹ in 6%, 100 µg l⁻¹ in 24% and 200 µg l⁻¹ in 10% samples, respectively. The arsenic concentration in drinking water ranged from 12.8 to 132.2 µg l⁻¹. The depth of source of drinking water (10-60 m) was also found with a mean of 36.12 ± 13.61 µg l⁻¹ arsenic concentration. Observations revealed that at depth ranging from 10 to 20 m, the mean level of arsenic concentration was 17.398 ± 21.796 µg l⁻¹, while at 21 to 40 m depth As level was 39.685 ± 40.832 µg l⁻¹ and at 41 to 60 m As level was 46.89 ± 52.80 µg l⁻¹, respectively. These observations revealed a significant positive correlation (r = 0.716, t = 4.215, P < 0.05) between depth and arsenic concentration in drinking water. The age of water sources were ranged from zero to 30 years. The study indicates that the older sources of drinking water showed higher chance of contamination. Results showed that group 21-30 years having maximum arsenic concentration with mean value of 52.57 ± 53.79 µg l⁻¹. Correlation analysis also showed a significant positive correlation (r = 0.801, t = 5.66, P < 0.05) between age of drinking water sources and their respective arsenic concentration (µg l⁻¹). Arsenic concentration in blood with mean value 0.226 ± 0.177 µg dl⁻¹ significantly increased as compared to control. The blood arsenic content correlated significantly (r = 0.6823, t = 3.93, P < 0.05) with drinking water arsenic level and exposure time (r = 0.545, t = 3.101 & *P < 0.05) for populations residing in Ballia districts. Observations and correlation analysis revealed that individuals having depth of drinking water sources 20-30 m were less affected with arsenic exposure.

Effect of chromium on the level of IL-12 and IFN-gamma in occupationally exposed workers.

Chromium may affect humoral and cellular immunity, acting on T lymphocytes as well as on granulocytes and monocytes cells. Cytokines play an important role in the immune balance. In this study, the level of IL-12 and IFN-gamma were evaluated in the sera and PHA/LPS stimulated culture supernatant of human PBMCs of healthy volunteers and occupationally exposed chromium workers. All the workers were highly exposed to chromium having mean of 104.65+/-77.21 microg/dL (range 23.7-316.8 microg/dL). A suspension of exposed and unexposed human PBMC (0.5x10(6) cells/ml) prepared and cultured in RPMI-1640 supplemented with 10% FCS for 18 h in the presence or absence of LPS (10 ng/ml) which used for stimulation of IL-12 and IFN-gamma. The level of IL-12 and IFN-gamma were evaluated in the sera samples as well as LPS stimulated and unstimulated culture supernatant of h-PBMCs of chromium exposed workers. In these chromium exposed workers the level of IL-12 was 433.66+/-197.49 pg/ml and 983.45+/-330.99 pg/ml in LPS stimulated culture supernatant of normal individuals and highly chromium exposed workers, which was significant (P<0.05). Although the level of IL-12 was (78.61+/-61.03 pg/ml to 146.52+/-46.37 pg/ml) elevated in unstimulated culture supernatant of h-PBMCs of chromium exposed individuals as compared to control, but it was not significant. This observation also suggests that a significant increase in IFN-gamma production in LPS stimulated and unstimulated culture supernatant of h-PBMCs of chromium exposed workers as compared to control. However, IFN-gamma level have a significant positive correlation between blood chromium level (r=0.833, t=6.3872, P 0.05) and exposure time (in years) (r=0.8916, t=8.3540, P 0.05) of the occupationally exposed workers.

Suppression of IL-6 level in human peripheral blood mononuclear cells stimulated with PHA/LPS after occupational exposure to chromium.

The toxic metals alter the immune response of animals as well as humans. In addition to the well documented and numerous toxic effect of chromium on various target organs, number of studies shown that acute and chronic exposure to inorganic chromium may result in impairment of immune functions in the experimental systems. Immunosuppression appears to be more subtle effect of exposure to heavy metals. Therefore, we have taken two different groups of chromium exposed individuals. These were leather tanning workers and chromeplaters. These groups of individuals were regularly exposed to chromium. All the leather tanning workers were highly exposed to chromium having a mean of 96.60+/-113.95 mg/dl (range 12.4-417.21 mg/dl). A suspension of exposed and unexposed human PBMC (0.5x10(6) cells/ml) prepared and cultured in RPMI-1640 supplemented with 10% FCS for 18 h in the presence or absence of PHA (5 microg/ml) and LPS (10 ng/ml) which used for stimulation of IL-2, IL-4, TNF-alpha, IL-10 and IL-6, respectively. The levels of Th1/Th2 cytokine: IL-2, IL-4, TNF-alpha, IL-10 and IL-6 were evaluated in the sera and PHA/LPS stimulated culture supernatant of human PBMCs of chromium exposed workers. In these workers the level of IL-6 was 543.95+/-123.75 pg/ml and 388.40+/-61.24 pg/ml in PHA/LPS stimulated culture supernatant of normal individuals and highly chromium exposed workers, which was significant (P<0.05). This observation suggests that IL-6 levels were suppressed in chromium exposed groups as compared to unexposed healthy volunteers. Although the level of IL-2 in PHA stimulated culture supernatant of PBMCs was suppressed in chromium exposed individuals but it was not significant, IL-4 and IL-10 could not be detected. However, there was no difference in TNF-alpha levels in sera samples as well as unstimulated culture supernatant of h-PBMCs of chromium exposed individuals as compared to control.