Purpose of ReviewThis review examines recent publications on rare earth elements (REE) in soils, critically evaluating their role as emerging soil contaminants. We emphasized new findings and main gaps using a previous review paper published in 2016 by our research group as a reference point. Three major subjects were prioritized: (1) sources, background levels, and behavior of REE in soils; (2) plant development and metabolism as affected by REE exposure; and (3) environmental and human health risk assessments of REE in the soil environment.Recent FindingsPublications addressing the occurrence and fate of REE in the soil environment have more than tripled in the last decade. Coincidentally, global REE exploration has more than doubled in the past 7 years. Because of their unique features, the global demand for REE is expected to increase by at least 50% in the next 10 years. As soils are the main sink of contaminants, we must continue to investigate the consequences of the unceasing addition of these elements in soil ecosystems.SummaryWe highlighted the main sources of REE, their background levels in selected global soils, and their physicochemical behavior. The relationship between REE and plants revealed potential benefits such as environmental stress tolerance. Finally, ecological and human health risk assessment data for REE in soils were carefully discussed in terms of their potential adverse effects on biota. We conclude with a survey in which prominent authors working with REE answered questions about challenges and opportunities for innovative research on REE in soil-plant-animal/human systems.

Mining contributes to an increased tax revenues, export earnings, employment opportunities, infrastructure development, and transfer of technology to the host countries. However, there is a high risk of socio-economic enclaves or environmental damages caused by mining operations which include the release of heavy metals into water and soil resources, air pollution, land degradation, and depletion of vegetation. Mineral exploration is often preoccupied with integrating relevant datasets and utilising various techniques to discover subtle surface indications of mineralisation and usually results in huge disturbances of large surface area and underlying strata including aquifers. These issues with mineral exploration are pronounced in developing countries where the primary goal of many investors is to look for the occurrence of mineral of interest and its economic viability with little or no attention to the associated hydrogeological risk. Hydrogeological Risk Assessment, even though crucial to the development of sound environmental impact assessment for a proposed mineral exploration project, is often not included in mineral exploration activities. This could potentially result in a significant health risk and environmental impact which could negatively impact various communities within the mining areas. In this research, an overview of the various stages involved in evaluating and assessing the hydrogeological risk from the initial exploration stage has been provided. A framework that will enable a short-term to long-term integrated groundwater resources management system into mineral exploration projects have also been developed. This framework would provide valuable information to stakeholders to verify whether a proposed project is likely to be debilitating to hydrogeology in a locality.

As typical antibiotics, tetracycline (TC) and sulfadiazine (SDZ) enter the human body through the food chain. Therefore, it is necessary to understand their individual and combined toxicity. In this study, the effects of TC, SDZ, and their mixture on cell viability, cell membrane damage, liver cell damage, and oxidative damage were evaluated in in vitro assays with human liver cells Huh-7. The results showed cytotoxicity of TC, SDZ, and their mixture, which induced oxidative stress and caused membrane and cell damage. The effect of antibiotics on Huh7 cells increased with increasing concentration, except for lactate dehydrogenase (LDH) activity that commonly showed a threshold concentration response and cell viability, which commonly showed a biphasic trend, suggesting the possibility of hormetic responses where proper doses are included. The toxicity of TC was commonly higher than that of SDZ when applied at the same concentration. These findings shed light on the individual and joint effects of these major antibiotics on liver cells, providing a scientific basis for the evaluation of antibiotic toxicity and associated risks.

A total of 30 samples from the downwind direction of a certain electroplating company in Jiaxing were collected in layers to analyze their heavy metal content. The soil risk assessment was conducted from the perspective of ecological and human health risks using the ground accumulation index method and human health risk assessment method. The results showed that in all samples, cadmium and arsenic far exceeded the soil background values, with an average exceeding multiple of 14.31 and 64.42, respectively, and a exceeding rate of 100%. After evaluation by the ground accumulation index, among these six heavy metals, arsenic and cadmium belong to extremely serious pollution levels. The human health risk assessment of electroplating plants found that in the exposure risk assessment, the ingestion value was much greater than the harm caused by breathing and skin, and the maximum exposure damage value of arsenic to children and adults was 4.17 x 10-3, among the carcinogenic risks, the risk brought by consumption is much greater than the respiratory and skin carcinogenic risk index, with the highest value score of 3.37 for cadmium, arsenic, and zinc carcinogenic risks 3.37 x 10-6, 2.42 x 10-3, 1.10 x 10-4.