Ecological risk assessment of hexavalent chromium and silicon dioxide in well water in Maros Regency, Indonesia

Assessment of the intrinsic bioremediation capacity of a complexly contaminated Yamuna River of India: a algae-specific approach

Nearly 57 million people depend on Yamuna's water for their daily needs and agriculture. This is the first study of assessment of the Yamuna River for five major pollutants - Nitrate, Sulfate, Phosphate, Silicon, and Chloride, and the role of inhabitant algal species for phycoremediation. Water samples were collected from 11 different locations across three different seasons and it was found that the concentration of these pollutants varies in different locations and seasons. The concentration of Nitrate 392.93 mg/L at ITO Monsoon 2021, Phosphate 86.25 mg/L at Baghpat, Silicon 257.34 mg/L at Faridabad, Sulfate 2165.949 mg/L at ITO during winter 2020, and Chloride 4400.741 mg/L at Old bridge during Monsoon 2021 are found maximum. A significant variation (p < 0.05) in the concentrations of Nitrate, Sulfate, Phosphate, Silicon, and Chloride before and after treatment with microalgae was observed in water samples. All six algae significantly remove all the pollutants, and the maximum pollutants removed are Phosphate and Nitrite. Scenedesmus sp., removes the highest 99.21% Phosphate and 86.31% Nitrate, whereas 78.50% of Sulfate was removed by Klebsormidium sp. The highest 92.77% Silicon and 86.20% Chloride were removed by Oocystis sp. This finding suggests that out of six algae, Scenedesmus sp., in the Yamuna water has grown primarily at all the sites and reduces maximum pollutants. The outcomes from this study confirms that Yamuna River is highly contaminated at all the sites from these five major pollutants and algae are still survive in highly contaminated Yamuna water where no other plants are grown and phycoremediate the water bodies even in the presence of very high-stress condition. These algae can further be utilized for biotreatment of any contaminated water body.

Health risk assessment of total chromium in the qanat as historical drinking water supplying system

This study investigated the health risk assessment of total chromium (Cr_T) in qanats of South Khorasan, Eastern Iran. For this, concentration of Cr_T in a total of 83 qanats were measured in summer 2020. Samples were initially tested in the field for temperature, pH, dissolved oxygen (DO), electrical conductivity (EC), and total dissolved solids (TDS). In the lab, collected samples were filtered and fixed with nitric acid (HNO₃) for the detection of Cr_T using inductively coupled plasma mass spectrometry (ICP-MS). Hazard quotient (HQ) and carcinogenic risk assessments were considered to evaluate the risks of Cr_T to inhabitants. Results showed that concentration of Cr_T ranged from 1.79 to 1017.05 μg L^-1, and a total of 25 stations illuminated Cr_T concentrations above the WHO standards (50 μg L^-1). HQ demonstrated HQ < 1 for 90.37% of studied samples with negligible hazard, whereas 9.63% of stations illuminated HQ ≥ 1 meaning the presence of non-carcinogenic risk for water consumers. Carcinogenic risk (CR) exhibited CR > 1.00E-04 in 81.93% of qanats while 18.07% of stations had 1.00E-06 < CR < 1.00E-04 meaning no acceptable and acceptable CR for the studied qanats, respectively. Zoning map displayed that qanats in the south of South Khorasan possessed the highest HQ, but north regions showed the lowest ones. Together, Cr_T in qanats of South Khorasan is above the WHO limit, which results in a high risk of carcinogenicity for residents, and in turn, more efforts should be made to provide hygienic groundwater for consumers.

Potentially Toxic Element Levels in Atmospheric Particulates and Health Risk Estimation around Industrial Areas of Maros, Indonesia

Air quality deterioration is a major environmental problem in Indonesia. This study evaluated the levels and health risks of potentially toxic elements (PTEs) in Maros Regency, Indonesia. Total suspended particulate matter was collected from industrial areas for PTE (Al, Pb, Cr, Cu, Ni, As and Zn) analysis using inductively coupled plasma optical emission spectrometry (ICP-OES). Samples were collected from six critical areas in the Bantimurung region as that is where marble, cement and limestone industries are located. A calculation of the non-carcinogenic and cancer risks was performed to determine the potential health exposures in adults and children. A Monte Carlo simulation with 10,000 iterations and a sensitivity analysis was carried out to identify the risk probability and the most sensitive variable contributing to cancer risk from PTE exposure in humans. The results showed that the concentration of PTEs decreased in the order of Zn > Al > Cr > Pb > Cu > Ni > As in the wet season, and Zn > Al > Pb > As > Cr > Cu > Ni in the dry season. The hazard index (HI) value for children was 2.12, indicating a high non-carcinogenic risk for children. The total cancer risk (TCR) values in adults and children were 3.11 × 10⁻⁵ and 1.32 × 10⁻⁴, respectively, implying that both are at risk for developing cancer. The variables with the most contribution to cancer risk from As, Cr and Pb exposure in adults and children were As concentration (33.9% and 41.0%); exposure duration (ED) (34.3%) and SA (40.7%); and SA (98.7 % and 45.4%), respectively. These findings could be used as the scientific basis for public health intervention and to raise awareness of the harmful health effects of particulate bound PTEs