Toxic Risk Assessment of Arsenic in Males Through Drinking Water in Tharparkar Region of Sindh, Pakistan

Humans are exposed to arsenic (As) through air, drinking water, and food. The arsenic (As) hazardous quotient was calculated on the basis of its concentration in drinking water of different origin and scalp hair of male subjects (n = 313), residents of different exposed and non-exposed areas of Sindh, Pakistan. The total As was determined in water and scalp hair samples, while As species were determined in water samples by advance extraction methodologies. The total As concentrations in drinking water of less-exposed (LE) and high-exposed (HE) areas was found to be 2.63 to 4.46 and 52 to 235, fold higher than the permissible limit, respectively, than recommended by World Health Organization (2004) for drinking water. While the levels of As in drinking water of non-exposed (NE) areas was within the permissible limit. The resulted data indicated that the dominant species was As(+5) in groundwater samples. The levels of As in scalp hair samples of male subjects of two age groups (18-30 and 31-50 years), belonging to NE, LE, and HE areas, ranged from 0.26 to 0.69, 0.58 to 1.34, and 15.6 to 60.9 μg/g, respectively. A significant correlation between As levels in drinking water and scalp hair was observed in HE area (r = 0.86-0.90, p < 0.001) as compared to those subjects belonging to LE area. A toxicity risk assessment was calculated as hazard quotient (HQ), which indicates that the study subjects of HE area have significantly higher values of HQ than LE. The population of As exposed areas is at high risk of non-carcinogenic and carcinogenesis effects.

Exposure of children to arsenic in drinking water in the Tharparkar region of Sindh, Pakistan

Humans can be exposed to arsenic (As) through air, drinking water, and food. The aim of this study was to calculate the hazard quotient (HQ) of As, based on its concentration in drinking water and the scalp hair of children (males) belonging to two age groups (5-10 and 11-14 years) who consumed water contaminated with different concentrations of As. The water samples were collected from As-exposed and nonexposed areas, which were classified as low-exposed (LE), high-exposed (HE), and nonexposed (NE) areas. The total concentration of inorganic As (iAs) and its species (As(III) and As(V)) in water samples of all selected areas was determined by advanced extraction methods. For purposes of comparison, the total As level was also determined in all water samples. The resulting data indicated that the predominant inorganic As species in groundwater samples was arsenate (As(V)). The As concentrations in drinking water of LE and HE areas were found to be 2.6-230-fold higher than the permissible limit for drinking water established by the World Health Organization (2004). However, the As levels in drinking water of the NE area was within the permissible limit (<10 μg/L). The As levels in the scalp hair samples from boys of NE, LE, and HE areas ranged from 0.16 to 0.36, 0.36 to 0.83, and 11.5 to 31.9 mg/kg, respectively. A significant, positive correlation was observed between the As levels in drinking water and scalp hair samples of children from the HE area, compared with the other two groups (p>0.01). The As toxicity risk assessment based on HQ for the NE, LE, and HE areas corresponded to <10, ≥ 10, and >10, respectively. These HQ values indicated the noncarcinogenic, less carcinogenic, and highly carcinogenic exposure risks faced by children from the NE, LE, and HE areas, respectively. It can be concluded that children consuming the groundwater of the LE (Khairpur Mir's) and HE (Tharparkar) areas of Pakistan are at a potential risk of chronic As toxicity.

Determination of nickel in blood and serum samples of oropharyngeal cancer patients consumed smokeless tobacco products by cloud point extraction coupled with flame atomic absorption spectrometry

Oropharyngeal cancer is a significant public health issue in the world. The incidence of oropharyngeal cancer has been increased among people who have habit of chewing smokeless tobacco (SLT) in Pakistan. The aim of present study was to evaluate the concentration of nickel (Ni) in biological samples (whole blood, serum) of oral (n = 95) and pharyngeal (n = 84) male cancer patients. For comparison purposes, the biological samples of healthy age-matched referents (n = 150), who consumed and did not consumed SLT products, were also analyzed for Ni levels. As the Ni level is very low in biological samples, a preconcentration procedure has been developed, prior to analysis of analyte by flame atomic absorption spectrometry (FAAS). The Ni in acid-digested biological samples was complexed with ammonium pyrrolidinedithio carbamate (APDC), and a resulted complex was extracted in a surfactant Triton X-114. Acidic ethanol was added to the surfactant-rich phase prior to its analysis by FAAS. The chemical variables, such as pH, amounts of reagents (APDC, Triton X-114), temperature, incubation time, and sample volume were optimized. The resulted data indicated that concentration of Ni was higher in blood and serum samples of cancer patients as compared to that of referents who have or have not consumed different SLT products (p = 0.012-0.001). It was also observed that healthy referents who consumed SLT products have two to threefold higher levels of Ni in both biological samples as compared to those who were not chewing SLT products (p < 0.01).