The upper reaches of the Crocodile River (West) system are located in the western basin of the Witwatersrand mountain chain, an area heavily influenced by gold mining. After the spill of highly acidic and contaminated mining-influenced water into the river system in 2002, chemical water treatment was implemented to compensate for the consequences of acid mine drainage. Some studies thereafter have shown metal concentrations of concern in the system, but never considered longer periods of time. For this study, we investigated water and sediments over a period of 13 months from 7 sampling sites in the system. In addition to physico-chemical parameters such as temperature, pH, and electrical conductivity, a multi-element analysis was conducted. We used various versions of atomic-absorption-spectroscopy, total reflection x-ray fluorescence spectroscopy, and inductively coupled plasma mass spectrometry in filtered and acidified water samples as well as sediment leachates. Concentrations of Ni, Zn, As, Pb, and U in the sediment were clearly elevated at the site closest to the mine as well as further downstream, some of them far exceeding quality guidelines. Moreover, dissolved Mn, Fe, Ni, Zn and U occurred irregularly in concentrations of concern at the site of mining-influenced water inflow. Our findings clearly indicate a risk of further and chronic mobilization of toxic elements from this site and a possible threat to the connected river system.

The task-specific ionic liquid trihexyltetradecylphosphonium 3-hydroxy-2-naphthoate, [P ₆₆₆₁₄ ][HNA], was successfully used to extract Ce, Nd and Lu from aqueous solutions. High nitrate concentrations had a strong positive impact on extraction.

(1) Background: All Austrian amphibians are affected by the degradation of habitats. Mining contributes to habitat destruction by the formation of spoil heaps and mine drainage waters. In Stadtschlaining/Burgenland, antimony mining led to increased arsenic (As) and antimony (Sb) concentrations in soil and water. This study investigates a contaminated creek, still inhabited by amphibians. (2) Methods: Water and soil were analyzed along the creek and correlated with the occurrence of amphibians. (3) Results: As and Sb were increased, with up to 49,000 mg/kg As and 2446 mg/kg Sb in the soil. Up to 317 mg/kg As and 156 mg/kg Sb became bioavailable under gastric, and up to 298 mg/kg As and 30 mg/kg Sb under intestinal conditions, and were absorbed upon ingestion of soil. Larvae of Salamandra salamandra were found throughout the creek; survival rates were low. Rana temporaria occurs in the most contaminated sections but does not propagate here. Bombina variegata appears occasionally. Amphibians seem not to be able to detect and avoid metal or metalloid contamination. (4) Conclusion: Survival of larvae is dubious, but adult amphibians survive without apparent damage under severe metalloid contamination.

The consequences of acid mine drainage (AMD) are apparent in water and sediment of the upper reaches of the Crocodile River (West) system, which is located in the western basin of the Witwatersrand mountain chain in South Africa. Another significant indicator for metal and metalloid pollution in aquatic systems is biota. In particular, in the case of AMD-impacted areas, which occur worldwide, biota could serve as an important bioindicator of contamination and also be useful in terms of remediation of pollutants. We investigated the content of Fe, Ni, Cu, Zn, As, Se, Ag, Cd, Hg, and Pb in the liver and muscle tissue of 4 fish species (Oreochromis mossambicus, Labeobarbus polylepis, Labeobarbus marequensis, and Clarias gariepinus) and in roots and stems of macrophytes Pontederia crassipes, Typha sp. and Phragmites australis taken from selected sites in the system. Metals and metalloids were analyzed in freeze-dried and acid-digested samples using graphite furnace atomic absorption spectroscopy, cold vapor atomic absorption spectroscopy, and total reflection X-ray fluorescence spectroscopy. We determined that the mean levels of Fe, Ni and Cu were increased in the roots of Typha sp. and P. crassipes at sites influenced by AMD. Both macrophytes could also be used for phytoremediation of Ni, Cu and Cd, with bioaccumulation factors above 1 at all study sites ranging from 1.1 (Cu) to 21 (Cd) for Typha sp. and 2.7 (Ni) to 25 (Cd) for P. crassipes. Plants were found to be better bioindicators for AMD than fish due to homeostatic regulation of Ni, Cu, and Zn in fish at chronic low-level pollution. An exception was the liver tissue of O. mossambicus, which accumulated high levels of Ni (2.98 ± 1.24 mg kg⁻¹ dw), Cu (184 ± 124 mg kg⁻¹ dw) and Ag (2.01 ± 0.51 mg kg⁻¹ dw), demonstrating its bioindicative potential for these metals. Our study allowed a detailed look at an AMD influenced river system, revealing results that clearly demonstrate the consequences of chronic low-level pollution, although water melioration is in place.

Lamproglena clariae , a gill parasite of Clarias gariepinus has previously been identified as a valuable indicator of effect for organic and metal pollution. The current study evaluates it as a bioindicator of metal accumulation by recording the concentration (mg/kg) of Mn, Fe, Zn, Se, and Sr in adult females and eggs collected at six sites along the Vaal River, South Africa. The data are compared to the metal concentrations recorded in water and sediment, and with infection variables calculated for L. clariae collected from C. gariepinus in March 2017 and October 2018. Metal concentrations in parasite samples were measured utilizing total reflection X‐ray fluorescence spectroscopy. This was the first time this method was used to measure metal concentration in L. clariae . Manganese, Fe, Cu, Se, and Sr concentrations differed between adult females and egg specimens and between the six sampling sites, following the difference in the metal concentrations in the water and sediment samples. More polluted sites had low prevalence and low abundance of L. clariae . In adult females, Mn, Fe, Cu, Zn, Se, and Sr had higher concentrations than the water at the more polluted sites. Metal concentration (Mn, Zn, Cu, and Se) was higher in adult females compared to eggs. However, the Fe concentrations were higher in eggs than in adult females. Metal concentrations in L. clariae females were generally higher than levels recorded in water and sediment samples, indicating biomagnification, and supporting the viability of L. clariae as an accumulation indicator. High concentrations of Fe in eggs suggest that Fe elimination may occur via vitellin maternal transfer to larvae. Practitioner Points: Fish ectoparasites have not received sufficient evaluation as indicators of pollution. Lamproglena clariae bioaccumulates metals in polluted environments. Lamproglena clariae eggs accumulate Fe to higher concentrations than the females that produce them.