Impact of anthropogenic activities on urban stream water quality: a case study in Guangzhou, China

Integrated Assessment of Water Environmental Health Risk through Drinking Water Ingestion in Lhasa River Basin: Quantitative Analysis and Environmental Significance

An integrated assessment of water environmental health risk through drinking water ingestion in Lhasa River has been implemented. The health risks caused by different pollutants in different age groups (children, juvenile and adult groups) are in the order of 10^-8 ~ 10^-7, 10^-7 ~ 10^-5 and 10^-13 ~ 10^-8 a^-1, respectively. The total health risks for all age groups are lower than the International Commission on Radiation Protection recommended value and the U.S. Environmental Protection Agency recommended value at all points except LS4, LS12 and LS13. The total health risk levels in different age groups at most points are class III or II, which means that there are low or negligible negative effect in these points and age groups. It is more important to monitor the arsenic concentration. The water environment quality protecting in Lhasa River Basin must be consistent with the clear water and blue sky protecting in Tibet Autonomous Region and the national ecological security barrier construction on the Tibetan Plateau.

Pollution Contribution Response in Governance and Potential Pollution Factors in Licun River

The development of the city results in deterioration of the water quality of the Licun River. As a result, years of governance have been conducted to improve its water quality. In order to clarify the response changes of water quality in the water governance, the governance process is divided into three stages (2000–2007, 2008–2016, 2017–2020) according to different priorities. Spearman’s rank correlation coefficient and the comprehensive pollution index are applied to analyze the variation of water quality response at various stages. In addition, the main pollution contributions with the governance changes were obtained. It is concluded that flood control and incomplete river pollution interception have a limited effect on water quality improvement, with NH3-N (ammonia nitrogen) and COD (chemical oxygen demand) being the main pollution contributions at the first stage. At the second stage, the point source control and sewage treatment facilities significantly improve water quality, and the main pollution contributions are NH3-N and TP (total phosphorus). At the third stage, sewage treatment facilities and supporting pipelines are improved, water sources are replenished, and the main pollution contribution is TN (total nitrogen). For further treatment, the factors affecting pollution are analyzed, including the contradiction of sewage system, point source pollution caused by pipe network problems, shortage of water resources, sludge pollution, and non-point source pollution.

A Surrogate Water Quality Index to assess groundwater using a unified DEA-OWA framework

In this paper, we introduce a new approach, based on a unified framework incorporating Data Envelopment Analysis (DEA) and Ordered Weighted Averaging (OWA), for assessing water quality in contextual settings that involve a large number of hydrochemical parameters. In order to enhance discrimination among water sources, the DEA model is adopted with data-driven input variables, called "surrogate optimistic closeness values," computed through an aggregation procedure that includes the observed values of the hydrochemical parameters with OWA weights. The proposed DEA-OWA methodology has been employed to assess the quality of 51 water samples, collected from irrigation wells in Sereflikochisar Basin, Turkey, by means of 19 hydrochemical parameters. Using different subjectivity levels, the Surrogate Water Quality Indices (SWQIs) that are produced are proven effective in enhancing discrimination among the water sources while enabling a more robust water quality-based ranking. The k-means analysis has been used for clustering the water quality of the wells into Excellent, Good, Permissible, and Unsuitable rather than using pre-set boundaries. Only one water source has been identified as Excellent, whereas 17.65%, 45.10%, and 35.29% of the sampled wells, respectively, are categorized with Good, Permissible, and Unsuitable water quality. Inferred from wells' location, the results suggest that the groundwater might be drastically affected by saline water intrusion from Lake Tuz. The latter conclusion has been corroborated through a Tobit regression analysis.

Anthropogenic impacts on isotopic and geochemical characteristics of urban streams: a case study in Wuhan, China

Urbanization and human activities have significantly modified the geochemical signatures of urban streams worldwide. However, the geochemical characteristics of urban streams in Wuhan, one of the core cities in the Yangtze River Economic Belt in China, remain largely unstudied. Here, we examined the stable isotopes and geochemistry of urban streams at 73 locations in the central districts in Wuhan during May 2019. Maps of isotopic signatures reflected a non-free-flowing state in part of the urban stream system in Wuhan. A lower DO and a higher EC level were found in urban streams relative to the adjacent Yangtze River. The Na⁺, K⁺, and Cl^- concentrations in urban streams were > 3.0 times as high as those in the Yangtze River, and there was a slight increasing trend between 1.1 and 1.4 times for other major ions. The mildly elevated Fe concentration (1.3 times) and markedly elevated Mn concentration (> 5.0 times) were observed in urban streams. Spearman's correlation analysis indicated strong positive bivariate correlations among Na⁺, K⁺, and Cl^- in urban streams, and an urban geochemical principal component was identified by principal component analysis. Plotting Na/(Na + Ca) versus total dissolved solids (TDS) indicated a potential risk of "urban stream syndrome." These findings can enhance the knowledge of anthropogenic impacts on current urban stream water quality and provide reference for the restoration and improvement of water ecology functions of the urban stream system in Wuhan.

Climatic seasonality and water quality in watersheds: a study case in Limoeiro River watershed in the western region of São Paulo State, Brazil

Applying the climatological water balance (WB) concept to describe the relationship between climatic seasonality and surface water quality according to different forms of land use and land cover (LULC) is an important issue, but little explored in the literature. In this paper, we evaluate the influence of WB on surface water quality and its impacts when interacting with LULC. We monitored 11 sampling points during the four seasons of the year, from which we estimate WQI (water quality index) and TSI (trophic state index). We found an effect of the seasonality factor on both WQI values (F(3,30) = 12.472; p < 0.01) and in TSI values (F(3,30) = 6.967; p < 0.01). We noticed that LULC interferes in the way that the water balance influences the WQI and TSI values since in sampling points closest to higher urban density, with little or no riparian protection, the correlation between water balance and water quality was lower. In the stations that had the lowest water surplus and deficit, there was positive linearity between water balance and WQI. However, in the seasons when the surplus and water deficit recorded were extreme, there was no linearity. We conclude that water deficiency impairs the quality of surface water. In the extreme surplus water season, the homogeneity of WQI samples was lower, suggesting a higher interaction between rainwater and LULC. This study contributes to design management strategies of water resources, considering the climatic seasonality for optimization.

Spatiotemporal distribution, source apportionment, and ecological risk of corticosteroids in the urbanized river system of Guangzhou, China

We investigated the occurrence and distribution of 24 selected corticosteroids (CSs) in the surface water of the Zhujiang River (ZR) system in Guangzhou, a highly urbanized river system receiving both treated and untreated municipal wastewater effluents. Twenty-two and sixteen CSs were detected in the tributaries and the main stream of the ZR system, and their concentrations ranged from less than the method quantification limit (fluticasone propionate) to 94 ng/L (clobetasone butyrate) and from 0.24 ng/L (cortisol) to 7.2 ng/L (clobetasone butyrate), respectively. We observed higher total CSs (∑CSs) concentrations in the tributaries (11-396 ng/L) relative to the main stream (5.5-33 ng/L) due to their proximity to densely populated residential areas. ∑CSs concentrations in the dry season were generally higher than those in the wet season due to low dilution from decreased river discharge. Principal component analysis and multiple linear regression analysis identified untreated domestic sewage to be the dominant source of CSs (t₂, contribution rate: 42.7%) in the urban rivers. Additional source contributions were from naturally attenuated treated and/or raw sewage (t₁, 21.5%) and effluents from wastewater treatment plants (t₃, 26.7%). CSs contribution was dominated by t₂ in the dry season, and the contributions from t₁, t₂, and t₃ showed no significant difference in the wet season. Risk assessment inferred that the ZR system is at medium to high ecological risk from CSs and is therefore a potential threat to the health of aquatic ecosystems. To prevent CSs pollution, our results demonstrate the need to develop effective control strategies to minimize the discharge of untreated waste to nearby rivers and to improve the capacity of wastewater treatment plants in Guangzhou. Further, we demonstrate that the concentrations of cortisone and fludrocortisone acetate are effective chemical indicators to estimate the level of natural and synthetic CSs contamination in urban rivers.

Assessment of Water Quality Evolution in the Pearl River Estuary (South Guangzhou) from 2008 to 2017

To control the water pollution in the Pearl River Estuary (PRE), a series of measures have been enacted in recent years. The efficacy of these measures on water quality improvement is, however, currently unknown. To evaluate the variation of water quality in response to the pollution control measures in the PRE during the last decade (2008–2017), our study conducted a long-term monitoring program of estuarine water in the representative city Guangzhou that targeted fecal coliform (F. Coli), biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), potassium permanganate index (CODMn), petroleum, total nitrogen (TN), ammonia nitrogen (NH3–N) and total phosphorus (TP). In the last decade, F. Coli, BOD5, CODCr and CODMn, petroleum and NH3–N have shown a significant reduction by 78.8%, 50.9%, 37.5%, 18.9%, 75.0% and 25.0%, respectively. In contrast, TN and TP remained stable. Water quality index calculations indicated that the water quality was elevated from the marginal–fair level to the good level, particularly after 2012. The biochemical pollutants and nutrients in the estuarine water most likely originated from the upper river due to the wastewater discharge, fecal pollution and agricultural input. The success of pollutant reduction could thus be attributed to industrial upgrading and relocation, as well as the improvement of the sewage treatment system in Guangzhou. However, efficient approaches to reduce TN pollution should be implemented in the future.

A novel approach for assessing watershed susceptibility using weighted overlay and analytical hierarchy process (AHP) methodology: a case study in Eagle Creek Watershed, USA

Watershed vulnerability and the characterization of potential risk are important inputs for decision support tools in assessing watershed health. Most previous studies have focused on the assessment of the environmental risk using physicochemical properties of surface water and mathematical models to predict the health of a watershed. Here, we present a new methodology for evaluating watershed vulnerability using the analytic hierarchy process (AHP) and weighted overlay analysis. The new methodology provides an inexpensive approach for assessing areas that need more investigation based on known factors such hydrogeological, geological, and climate parameters without the need for site-specific physicochemical data. The proposed method was implemented using six main factors that influence water quality: land use, soil type, precipitation, slope, depth to groundwater, and bedrock type. Vulnerability was predicted for ten sub-watersheds within the Eagle Creek Watershed in Indiana using publicly available data input into geographic information system. Combination of watershed susceptibility assessment and GIS spatial analysis tools was used to produce the maps that show the susceptible zones within a watershed. A comparison of the resulting vulnerability estimates showed the expected significant positive correlations with measurements of nitrate, phosphate, temperature, and electrical conductivity. Likewise, the vulnerability estimates negatively correlated with dissolved oxygen and E. coli. Furthermore, the validation of the proposed approach revealed that the areas predicted to have high vulnerability did have lower water quality indices; the results showed a high negative correlation (r² = 0.77, p < 0.05) between water quality index (WQI) and vulnerability which strongly suggests this method can be used successfully to assess a watershed's susceptibility.

Hydrogeochemical Characteristics and Controlling Factors of the Lhasa River under the Influence of Anthropogenic Activities

Anthropogenic activities have had diversiform impacts on the surrounding river and environments. A study on the surface water of the Lhasa River Basin was undertaken to assess its hydrogeochemical characteristics under the influence of anthropogenic activities. A total of 16 samples collected from the Lhasa River were analyzed for pH, electric conductivity (EC), oxidation-reduction potential (ORP), total dissolved solids (TDS), major cations (K+, Na+, Ca2+, and Mg2+), major anions (Cl−, SO42−, HCO3−, and NO3−), and trace metals. The pH of the analyzed water samples varied from 6.40 to 9.10, indicating alkaline in nature. The EC values varied from 77.3 to 213 μs/cm while the TDS values varied from 73.37 to 217.55 mg/L. HCO3− and SO42− are the dominant anions while Ca2+ and Na+ are the dominant cations in the river water. The concentration of alkaline earth metals (Ca2+ + Mg2+) exceed the alkali metals (Na+ + K+) and HCO3− dominates over SO42− + Cl− concentrations in the majority of the surface water samples. Ca2+-Mg2+-HCO3− and Ca2+-Mg2+-Cl− are the dominant hydrogeochemical facies in the surface water of the area. The water chemistry is mainly controlled by rock weathering with secondary contribution from anthropogenic sources. The content of trace elements in the Lhasa River is low, basically at the natural background value. The high content of individual elements is mainly due to the mineral resource exploitation and geothermal resources in the basin. Countermeasures and attention should be payed to these aspects, such as the construction of water conservancy facilities, urban economic development, the development of mining activities, and sewage and wastewater discharge, so as to protect the water quality and sustainable development of the Lhasa River Basin.

Using multivariate statistical analyses to identify and evaluate the main sources of contamination in a polluted river near to the Liaodong Bay in Northeast China

Using multivariate statistical analysis, the study evaluated anthropogenic sources of river water contamination and their relationships with river water quality in the Haicheng River basin near to the Liaodong Bay in Northeast China. The results showed that nitrogen (N) and phosphorous (P) were identified as the main pollutants in the river water by factor analysis. Human population and elevational gradient were all significantly correlated with N, P, and other water quality variables in correlation analysis and explained chemical oxygen demand (COD), N, and P variables from 23.9% (TN) to 53.1% (NH₃⁺-N) of the total variances in regression analysis, indicating that population and its distribution were all responsible for river contaminations, especially for COD, N, and P contaminations. The excessive applications of fertilizers and pesticides were all positively correlated with nitrogen variables and nitrogen pollution factor in correlation analysis, suggesting that agricultural activities were contributed to the river nitrogen pollution. Due to inadequate or lack wastewater treatment facilities, huge amounts of domestic sewage and industrial effluents were released into the river, becoming the predominant anthropogenic sources for the river water deterioration of COD, N, and P. Multivariate statistical analysis provided useful tools to correlate sources of contamination with water quality data. This approach will provide a better management for river pollution control in a human-driven river ecosystem.

Index for nitrate dosage calculation on sediment odor control using nitrate-dependent ferrous and sulfide oxidation interactions

Nitrate-driven sulfide and ferrous oxidation have received great concern in researches on sediments odor control with calcium nitrate addition. However, interrelations among sulfide oxidation, ferrous oxidation and their associated microbes during the nitrate reduction process are rarely reported. In this work, a n_NO3/n_(S+Fe) ratio (mole ratio of NO₃^- concentration to S^2- and Fe²⁺ concentration) was first introduced as an index for calcium nitrate dosage calculation. Then certain amount of calcium nitrate was added to four sediment systems with various sulfide and ferrous initial concentration to create four gradients of n_NO3/n_(S+Fe) ratio (0.6, 0.9, 1.5 and 2.0) for treatment. Furthermore, the significant variations of sulfide and ferrous oxidation, microbial diversity and community structure were observed. The results revealed that at low n_NO3/n_(S+Fe) ratio (0.6 and 0.9) systems, sulfide seemed prior to ferrous to be oxidized and no obvious ferrous oxidation occurred. Meanwhile, sulfide oxidizing associated genus Sulfurimonas sp. became dominant in these systems. In contrast, sulfide and ferrous oxidation rate increased when n_NO3/n_(S+Fe) ratio reached 1.5 and 2.0 (two and three times of theoretically required amount for sulfide and ferrous oxidation), which made Thiobacillus sp. more dominant than Sulfurimonas sp. Hence, when n_NO3/n_(S+Fe) ratio of 1.5 and 2.0 were used, sulfide and ferrous could be simultaneously oxidized and no sulfide regeneration appeared in two months. These results demonstrated that for sulfide- and ferrous-rich sediment treatment, the nitrate consumed by ferrous oxidation should be taken into account when calculating the nitrate injecting dosage. Moreover, n_NO3/n_(S+Fe) ratio was feasible as a key parameter to control the oxidation process and as an index for calcium nitrate dosage calculation.

Environmental pollution of electronic waste recycling in India: A critical review

The rapid growth of the production of electrical and electronic products has meant an equally rapid growth in the amount of electronic waste (e-waste), much of which is illegally imported to India, for disposal presenting a serious environmental challenge. The environmental impact during e-waste recycling was investigated and metal as well as other pollutants [e.g. polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs)] were found in excessive levels in soil, water and other habitats. The most e-waste is dealt with as general or crudely often by open burning, acid baths, with recovery of only a few materials of value. As resulted of these process; dioxins, furans, and heavy metals are released and harmful to the surrounding environment, engaged workers, and also residents inhabiting near the sites. The informal e-waste sectors are growing rapidly in the developing countries over than in the developed countries because of cheapest labor cost and week legislations systems. It has been confirmed that contaminates are moving through the food chain via root plant translocation system, to the human body thereby threatening human health. We have suggested some possible solution toward in which plants and microbes combine to remediate highly contaminated sites.