Pollution Distribution of Potentially Toxic Elements in a Karstic River Affected by Manganese Mining in Changyang, Western Hubei, Central China

Abstract

This study investigated the distribution, pollution level and potential ecological risk of potentially toxic elements (PTEs) from manganese mining in a karstic Danshui River, in Changyang, Western Hubei, Central China. River water and sediments were collected for seven PTEs measurement (As, Cd, Cr, Cu, Mn, Pb and Zn), as well as pH and Eh of the river water were measured. Results showed that the major pollutant was Mn, the river water environment was mainly acidic and oxidizing (288 < Eh, pH < 6.3), and the pollution distribution of Mn in the study area was dominated by the combination of natural processes and anthropogenic activities. In the river water, according to the contamination factor (CF) and pollution load index (IPL) results, Mn was considered the main pollutant. There was low As and Pb pollution downstream as well as Cu pollution upstream. Upstream and downstream areas were the main polluted river sections of the river water samples collected. In river sediments, based on the results of the geo-accumulation index (Igeo) and potential ecological risk index (IPER), it was determined that there was only considerable Mn pollution. The IPER of the PTEs from the river sediments was at acceptable levels, only Mn upstream performed at a moderate ecological risk level. According to Pearson correlation and principal component analysis, Mn originated from manganese mining activities, Cd, Cr and Zn were of natural origin, and Cu may have come from both mining and natural origin, whereas Pb and As were mainly related to the daily activities. Consequently, elemental speciation, mining activities and the distribution of water conservancy facilities were the main impacts of PET pollution distribution in this river.

Metals and Metalloid Concentrations in Fish, Its Spatial Distribution in PPC, Philippines and the Attributable Risks

“…The findings of the study showed that among the MMs in BMF analyzed, it was Mn concentrations in both BMF were higher than the permissible limit. This is a similar result to the study of Ali et al (2021) [ 69 ], in which Mn was one of the metals that tend to bioaccumulate highly in the muscle and liver of common carp ( Cyprinus carpio ) exposed to manganese sulphate and chromium chloride solution for 96 h. Mn can be present in aquatic environments due to natural causes (i.e., weathering of rocks) but primarily from anthropogenic activities such as mining [ 70 ] and domestic and industrial effluents [ 71 ]. A constant intake of fish highly contaminated with Mn may pose adverse health effects to the local population, such as neurodegenerative disorders [ 72 ], liver damage [ 73 ], and cardiovascular diseases [ 74 ].…”

Ammonium Uptake, Mediated by Ammonium Transporters, Mitigates Manganese Toxicity in Duckweed, Spirodela polyrhiza

“…In particular, in great duckweed, Spirodela polyrhiza , the first characteristic symptoms of Mn stress appeared in form of characteristic brown spots when concentration of Mn was 40 mg/L (0.73 mM); however, the symptoms were largely reduced by the presence of ammonium in the medium in addition to nitrate. This observation, together with (i) increasing pollution of water resources with heavy metals [ 34 , 35 , 36 , 37 ], (ii) multiple previous reports linking the level of toxicity caused by various heavy metals to the nitrogen metabolism [ 12 , 13 , 14 , 15 , 16 ] and (iii) availability of the solid set of data on whole Spirodela genome sequences [ 45 , 63 , 64 ], encouraged us to take a closer look at Mn toxicity in S. polyrhiza in relation to the source of inorganic nitrogen with a special attention on the species’s ammonium transporters (AMTs).…”

“…High concentrations of this microelement can also prevent the uptake and translocation of other essential elements such as Ca, Mg and Fe inducing their deficiencies which is considered as an explanation for the inhibition of chlorophyll biosynthesis and growth [ 31 , 32 ]. Moreover, modern human activities such as mining, metal smelting and the application of fertilizers and fungicides to agricultural land have raised the Mn content in soil, sediments and groundwater [ 33 , 34 , 35 , 36 ]. These developments pollute the environment, negatively affect ecosystems and lead to accumulation of Mn in the food chain [ 37 , 38 ].…”