Pollution, risks, and sources of heavy metals in sediments from the urban rivers flowing into Haizhou Bay, China

Muhammad

et al. 2022

Front. Environ. Sci.

Arsenic is considered a poison because of its seriously toxic effects on the human body; elevated concentrations of arsenic in drinking water have been reported in different parts of the world. Investigating the arsenic distributions in soil, surface water (SW), and groundwater (GW) is an interesting topic of research, along with probing its correlations with local factors of the ecosystem and other hydrogeochemical parameters. This study mainly aims to investigate the impacts of various factors on elevated arsenic concentrations in water and soil. The following factors are assessed for their relationship to the propagation of arsenic in Jianghan Plain, which is the study area: population density, pumping rate, rain, land use, surface elevation, water level, and heavy metal contamination. The arsenic contamination potential prediction map and categories were developed using GIS-based techniques, such as ordinary kriging and quantile methods. Then, the “raster calculator” tool was applied to verify the impacts of the abovementioned factors on arsenic concentration. Eighty-four single-factor, bi-factor, and multi-factor models were established to investigate the effective combinations among the factors. Land use and pumping rate were identified from the soil through an equal frequency tool, whereas water population density and pumping rate were obtained with high matching percentages. The arsenic concentrations varied in the ranges of 0.0001–0.1582 mg/L in GW, 0.0003–0.05926 mg/L in SW, and 1.820–46.620 mg/kg in soil sediment. The single factors showed the best equal frequency of arsenic concentration in water for population density (68.62%) and in soil for land use (65.57%) and pumping (63.66%). Statistical calculations with percentage frequency factors also depicted a positive trend. Arsenic was reported to have high correlations with Fe in GW (r2 = 0.4193), with EC in SW (r2 = 0.4817), and with Cu in soil (r2 = 0.623). It is observed that the alkaline behaviors of water bodies are associated with arsenic mobility. Elevated arsenic values were observed in grids along surface flows with high anthropogenic activities and urbanization. Additionally, low concentrations of Fe depicted reduced activities in aquifer systems. Filtering drinking water as well as controlling the suspected sources and factors affecting concentrations of arsenic in the three phases are options for reducing the health risks of the local populations.

Section: Resultsmentioning

confidence: 99%

Spatial distribution and risk identification of arsenic contamination in water and soil through GIS-based interpolation techniques in Jianghan Plain, Central China

Muhammad

et al. 2022

Front. Environ. Sci.

“…The bays in eastern China have been seriously polluted with heavy metals for a long time due to intensive anthropic pressure. In these pollutions and sediments, Cd poses a considerable ecological risk due to its high enrichment [ 43 ]. In our study, marine crustacean was the main Cd source of aquatic foods and contributed 81.66%.…”

Section: Discussionmentioning

confidence: 99%

Cadmium Exposure in Aquatic Products and Health Risk Classification Assessment in Residents of Zhejiang, China

He,

Fang,

Pan

et al. 2023

Foods

Cadmium (Cd) pollution of food safety is a prominent food safety concern worldwide. The concentration of Cd in six aquatic food categories collected from 2018 to 2022 was analyzed using inductively coupled plasma mass spectrometry, and the Cd exposure levels were calculated by combining the Cd concentration and food consumption data of 18913 urban and rural residents in Zhejiang Province in 2015–2016. The mean Cd concentration was 0.699 mg/kg and the mean Cd exposure of aquatic foods was 0.00951 mg/kg BW/month for the general population. Marine crustaceans were the largest Cd contributor, corresponding to 82.7%. The regional distribution results showed that the average Cd exposure levels of 11 cities did not exceed the provisional tolerable monthly intake (PTMI). According to the subgroups, the Cd mean exposure level of 2–3-year-old children was significantly higher than that of the other age groups but did not exceed the PTMI. Health risk classification assessment demonstrated that the final risk score was six, and the health risk level of Cd exposure in aquatic products in the Zhejiang population was medium. These results demonstrated that the risk of Cd exposure in certain food types or age groups should be given more concern.

“…Inshore regions with above‐average long TT in the baseline scenario (e.g., Regions 1 and 2, Figure 4a) are severely (Figure 1a) and frequently (Figure 2a) eutrophic. For example, Region 1, with the median TT of 537 days, is also highly enriched with heavy metals, pesticides, and organic pollutants (Deng et al., 2022; Liu et al., 2008; Shi et al., 2022). However, eutrophication in Region 1 is not as frequent as in other inshore regions (Figure 2).…”

Section: Discussionmentioning

confidence: 99%

A Physical Perspective of Recurrent Water Quality Degradation: A Case Study in the Jiangsu Coastal Waters, China

et al. 2023

Estuarine‐coastal systems receive pollutants from various sources at an alarming rate. Some systems are extremely susceptible to terrestrial input, as a relatively small amount of pollutant loading induces lasting water quality degradation. The Jiangsu coastal waters (JCWs), located in the southwestern Yellow Sea, are such areas that lack large river discharge but suffer from recurrent eutrophication recently. We hypothesize that the low flushing efficiency in the JCWs largely accounted for the susceptibility to coastal pollution. To test it, transit time (TT) and pollutant flushing rates in the JCWs were estimated under various scenarios using a validated three‐dimensional hydrodynamic model. Results show that TT in many inshore waters of the JCWs and the northern radial sand ridges is >240 days, which are consistent with the observed frequently eutrophic areas. The JCWs are better flushed and thus less eutrophic in summer, as a consequence of the stronger tidal residual coastal circulation. The baroclinic pressure gradient, modulated by the formation and destruction of thermal stratification in offshore waters, poses a dominant control on the seasonal variations of the coastal circulation and flushing rates, while wind effects are secondary. River‐borne pollutants from the Yangtze and Jiangsu local rivers are shown to primarily affect regions south and north of 32.5°N, respectively. Our study interprets the vulnerability of the JCWs to pollutant enrichment from a physical perspective and finds the flushing efficiency to be a good indicator of eutrophication, providing references for environmental managers of local and global estuarine‐coastal systems with recurrent pollution.