The Effectiveness of an Artificial Floating Wetland to Remove Nutrients in an Urban Stream: A Pilot-Study in the Chicago River, Chicago, IL USA

Water quality and hydrochemical assessments of thermal springs, Gandaki Province, Nepal

Thermal springs are the sites where the water temperature lies above ambient temperature. They are widely used for power generation, hot water spas, balneotherapy, agriculture, laundering, and aquaculture. In Nepal, many thermal springs are reported but scientific understanding on water quality and hydrogeochemistry of the springs is very limited. In this study, a total of 28 physico-chemical parameters were measured in water samples collected from 12 thermal springs from Gandaki Province, Nepal. Correlation matrix and multivariate statistical analysis such as principal component analysis (PCA) and cluster analysis were used to understand the water quality and hydrogeochemistry of the hot water springs. The pH, temperature, electrical conductivity, total dissolved solids, and turbidity in the hot water springs ranged from 7.3 to 8.8, 31.6-64.3 °C, 206-16270 μS/cm, 115-6637 mg/L, and 0.21-63.7 NTU; respectively. The dominance order of major anions and cations were: Cl^- > HCO₃^- > SO₄^2- > NO₃^- > F^- and Na⁺ > Ca²⁺ > K⁺ > Mg²⁺; respectively. Comparison of the water quality parameters with the WHO and National Water Quality Standards suggested that the majority of the parameters were within the safe limit. Out of 9 heavy metals and trace elements analyzed Zn²⁺, Ni²⁺, Cr³⁺, Cd⁺², Hg (total), and Pb²⁺ were found below the safe limit but Fe (total), As (total) and Cu (total) were found higher than the WHO safe limit in total of 3, 5 and 1 sampling sites; respectively. The water quality index (WQI), sodium absorption ratio (SAR), and magnesium hazard (MH) ratio in the hot water springs ranged from 40.9 to 573, 2.2-49.3, 7.1-70.8; respectively. The result of PCA analysis showed that four principal components are required to explain hydrogeochemistry. Cluster analysis suggested that the sampling sites can be grouped into three distinct clusters based on total dissolved solids. Interestingly, the classification of hydrochemical facies using a Piper diagram suggested that 7 out of 12 thermal springs have Na-Cl type water. Finally, a perspective on the suitability of the hot springs for hot water spas and balneotherapy and policy recommendation is provided.

Evaluating the impact of turbidity, precipitation, and land use on nutrient levels and atrazine concentrations in Illinois surface water as determined by citizen scientists

The objective of this study was to evaluate the impact of turbidity, precipitation, land use, and five-week variation on nutrient levels and atrazine concentrations across Illinois state. To acquire the greatest number of samples in a cost and time-sensitive manner, data were collected by citizen scientists. Volunteers collected data regarding five water quality metrics: nitrites, nitrates, phosphates, atrazine, and turbidity once per week from April 19 until May 17, 2017. A subset (24 %) of volunteers also collected turbidity measurements. Data regarding precipitation was obtained from the Community Collaborative Rain, Hail and Snow Network (CoCoRaHS), a long-standing grassroots volunteer network of backyard weather observers. Three ordinal regression analyses were performed: one without a blocking effect, a second with week as a blocking effect, and a third with watershed as a blocking effect. In all cases, turbidity was significantly associated with elevated levels of nitrate (Pseudo R²-0.48 to 0.94) and phosphate (Pseudo R²-0.60 to 0.80), while precipitation was significantly associated with elevated levels of nitrate (Pseudo R²-0.25 to 0.35). While analyzing five-week variation, the nitrite and nitrate levels, but not phosphate or atrazine, tended to increase at each site. Further, nitrite and nitrate levels significantly varied between the four land uses - agricultural, urban, suburban, and park. When data were analyzed by the three most well-sampled watersheds, Kankakee, Des Plaines, and Chicago, it was identified that the nutrient levels in the Kankakee and Chicago watersheds were significantly elevated relative to the Des Plaines watershed. Finally, cluster analysis identified that clusters dominated by agricultural land, and to a lesser extent suburban land use, had the most elevated nutrient concentration and the greatest frequency of atrazine hits. Data collected by citizen scientists can provide insight into the geospatial variability of nutrients and agrichemicals and can do so across large geographies.