Spatiotemporal variations of 2,4-dichlorophenoxy acetic acid with the role of sugarcane industry and related human health risk assessments in the Shadegan International Wetland.

2,4-Dichlorophenoxyacetic acid (2,4-D) is the most important pesticide widely used in Khuzestan province. This study aimed to determine the ecological risks assessment in fish, plant tissues, and trends in 2,4-D urinary biomarker concentration in humans of Shadegan International wetland, Iran. Sampling was carried out from three areas: freshwater, saltwater, and brackish water. The average concentration of 2,4-D at point 38, taken from the wetland's northern parts, was 15.73 µg/L. In the lower regions, it reached 326 µg/L at point 25. From points 37 to 16, it was higher than the international standard. The increasing trend of 2,4-D concentration was observed from point 36 to the middle of the wetland. The non-carcinogenic risk through ingestion and skin contact for children and adults was 3E-3 and 1.5E-2, 2.1E-3, and 8.6E-5, respectively, and through fish, consumption was 7.1E-4 for both groups. HI values were below one (< 1), indicating no health risk. HQ values in the summer were more than one (> 1), indicating the high risk to aquatic organisms and human health.

Arsenic in drinking water and kidney cancer: a systematic review.

OBJECT: Arsenic as a chemical is found in rock, soil, air and used in various industries and their products, such as colors, hairs, and fertilizers. Humans may be exposed to arsenic mainly through food and drinking water. Due to its adverse health effects, its presence in drinking water has become a public health concern. METHODS: In this systematic review, we investigated the relationship between arsenic concentration in drinking water and the risk of kidney cancer in humans. For this reason, various electronic databases were searched from 1992 February to November 2021. In this review, three ecological studies, two case-control studies, and four cohort studies were investigated. RESULTS: High levels of arsenic (100 µg/L) have been reported in many countries such as southwest Taiwan, Niigata, Argentine, and northern Chile. A significant relationship was observed between kidney cancer incidence and its mortality rate with high arsenic levels in drinking water. CONCLUSIONS: Despite the limitations in some previous studies, reviewing and comparing the data of different regions indicates a scientific relationship between kidney cancer incidence and high concentrations of arsenic in drinking water.

Effective bioremediation of petroleum-contaminated saline soil using halotolerant Bacillus strains isolated from the Persian Gulf.

A consortium isolated from the Persian Gulf is evaluated for its ability to bioremediate petroleum-contaminated soils. The soil sample was collected from oil fields of South Western Iran. The crude oil concentrations were set to 1000-10,000 mg/kg, and the sodium chloride concentration was set to 0.5%, 1%, 1.5%, 2%, and 2.5%. Operational parameters including volume (2-20 ml) and soil moisture (25%, 50%, and 100%) were studied consecutively according to one factor at the time of experimental design. A total number of eight different isolates capable of degrading crude oil were isolated from hydrocarbon-contaminated sites (KL1-KL8). The removal efficiency of Total petroleom hydrocarbons (TPH) with an initial concentration of 1000 mg/kg for numbers of bacterial cells per gram soil of 2, 10, and 20 CFU/g was 20.9%, 45%, and 60%, respectively. The removal efficiency of TPHs (initial concentration of 1000 mg/kg) at the end of fifth week for salinity amounts of 0.5%, 1%, 1.5%, 2%, and 2.5% was 10.87%, 22.4%, 25.7%, 68.6%, and 60.5%, respectively. The TPHs biodegradation efficiencies at different soil/water ratios of 25%, 50%, and 100% (slurry) were 12%, 28.7%, and 60.8%, respectively. In sunflowers, there was no statistically significant difference in seed germination for different levels of soil pollution (p > 0.05). The results of the current work suggest that this process is a viable and efficient method for remediating contaminated sites. To enhance the removal results in real soil, a scale-up study should also be conducted.

Spatial distribution, ecological and health risk assessment and source identification of atrazine in Shadegan international wetland, Iran.

Recently, atrazine has been increasingly used to control weeds in the corn and sugarcane farms, which affects the water resources and aquatic organisms. In this study, atrazine residual concentrations in water and fish samples of the Shadegan wetland (Iran) were investigated. Furthermore, the health and ecological risk assessment were calculated. A total of fifty water samples were collected from the wetland during three periods with a four-month time interval. Also, ten samples of ten different fish species were analyzed at the same time. The estimation of acceptable daily intake and comparison with international standards indicates danger to adjacent residential areas of wetland. Non-carcinogenic risk analysis showed that total hazard quotient (HQing + HQderm) were below the acceptable limit and there is no danger to the residents of the area. Atrazine concentration in the water and fish samples ranged between 0 and 2175.8 µg/L, and 0 to 35.58 µg/L, respectively. Results showed that 88% of the water samples were higher than EPA and WHO guidelines for drinking water in summer. The concentrations of atrazine in fish samples in summer were more than other seasons. Analysis of ecological risk assessment also showed that considering the average atrazine concentration in three seasons, the risk exposure was very high. This study will be beneficial to the both residents and government officials in management of Shadegan wetland pollution in term of toxic compounds.