Dissolved trace elements and nutrients in the North Sea-a current baseline.

Primary production is an important driver of marine carbon storage. Besides the major nutrient elements nitrogen, phosphorus, and silicon, primary production also depends on the availability of nutrient-type metals (e.g., Cu, Fe, Mo) and the absence of toxicologically relevant metals (e.g., Ni, Pb). Especially in coastal oceans, carbon storage and export to the open ocean is highly variable and influenced by anthropogenic eutrophication and pollution. To model future changes in coastal carbon storage processes, a solid baseline of nutrient and metal concentrations is crucial. The North Sea is an important shelf sea, influenced by riverine, atmospheric, Baltic Sea, and North Atlantic inputs. We measured the concentrations of dissolved nutrients (NH4+, NO3-, PO43-, and SiO44-) and 26 metals in 337 water samples from various depths within the entire North Sea and Skagerrak. A principal component analysis enabled us to categorize the analytes into three groups according to their predominant behavior: tracers for seawater (e.g., Mo, U, V), recycling (e.g., NO3-, PO43-, SiO44-), and riverine or anthropogenic input (e.g., Ni, Cu, Gd). The results further indicate an increasing P-limitation and increasing anthropogenic gadolinium input into the German Bight.

Biomonitoring of rare earth elements in Southern Norway: Distribution, fractionation, and accumulation patterns in the marine bivalves Mytilus spp. and Tapes spp.

Growing extraction and usage of rare earth elements and yttrium (REY) for medical and industrial applications has resulted in increased discharges into the marine environment. Using Mytilus spp. Mussels and Tapes spp. clams as bioindicator organisms, we analyzed 15 REY in soft tissues of specimens collected at two potentially polluted sites in Southern Norway: in the vicinity of an industry producing gadolinium-based MRI contrast agents (GBCAs) (Lindesnes) and in an industrially-affected fjord (Porsgrunn). The spatial distribution of REY and shale-normalized fractionation patterns were determined to assess the potential anthropogenic contribution of REY at the sites. At both sites, the REY fractionation pattern in soft tissue was characterized by enrichment of light rare earth elements (LREE) over heavy rare earth elements (HREE), while also displaying negative cerium and small positive gadolinium (Gd) anomalies. LREEs contributed to over 80% of the total REY concentrations, with increasing relative enrichment following higher total REY. Gd anomalies remained conserved in most sites despite significant differences in total REY; however, a high Gd anomaly (Gd/Gd* = 4.4) was found downstream of the GBCA industry spillwater outlet, indicating biotic uptake of excess anthropogenic Gd at this site. Total REY concentrations in clams in Porsgrunn were one order of magnitude higher than in mussels in Lindesnes. This may be attributable to freshwater influences in Porsgrunn, where clams collected closer to the river mouth had significantly higher total REY concentrations. This study constitutes the first assessment of REY concentrations in marine bivalves in Norway and can provide useful information for future biomonitoring studies on REY contamination.

Understanding Rare Earth Elements concentrations, anomalies and fluxes at the river basin scale: The Moselle River (France) as a case study.

Anthropogenic activities linked to various new technologies are increasingly disrupting REEs biogeochemical cycles. A catchment-based perspective is therefore necessary to distinguish between natural (i.e., changes in lithology) and human-related sources of REEs variability. In the present study, REEs patterns, anomalies and fluxes were investigated in the French part of the Moselle River basin (Moselle River itself and some of its headstreams and tributaries). The REEs patterns in the headstream waters were highly variable and mostly related to the complex underlying lithology (granite, sandstone, tuff and graywacke). Along the Moselle River, the presence of positive Gd anomalies and a regular LREEs depletion/HREEs enrichment pattern on sandstone/limestone substrates were the most distinctive features. The Gd anomaly varied from 1.8 to 8.7, with anthropogenic Gd representing 45 to 88% of the total Gd. A linear relationship was obtained between the anthropogenic Gd flux and the cumulative population along the watershed. However, the magnitude of the Gd anomalies was shown to depend on the methodological approach chosen for their calculation. The use of a threshold value to identify the presence of an anthropogenic Gd anomaly may therefore be basin (and lithology) dependent, and care has to be taken in comparing results from different rivers or lithologies. Concentration of anthropogenic Gd in the Moselle River and its tributaries were close to, or above, the value of 20 ng/L reported in literature to elicit adverse biological effects in laboratory cell cultures. The ecotoxicological significance of Gd anomalies deserves further investigation because concentrations of anthropogenic Gd may also vary depending on the methodological approach used for calculating Gd anomalies.

Anthropogenic gadolinium in freshwater and drinking water systems.

The increasing use of gadolinium-based contrast agents (GBCAs) for magnetic resonance imaging is leading to widespread contamination of freshwater and drinking water systems. Contrary to previous assumptions that GBCAs are stable throughout the water cycle, they can degrade. The stability of GBCAs depends largely on their organic ligands, but also on the physicochemical conditions. There is specific concern regarding UV end-of-pipe water treatments, which may degrade GBCAs. Degradation products in drinking water supplies can increase the risk of adverse health effects. This is of particular relevance where the raw water for drinking water production has a higher proportion of recycled wastewater. GBCAs concentrations in aquatic systems, often referred to as anthropogenic gadolinium, are determined using a variety of calculation methods. Where anthropogenic gadolinium concentrations are low, the inconsistent use of these methods results in high discrepancies and high levels of uncertainty. The current COVID-19 crisis will, in the short-term, drastically decrease the input of GBCAs to freshwater systems. Temporal variations in anthropogenic gadolinium concentrations in river water can be used to better understand river-aquifer interactions and groundwater flow velocities. Collecting urine from all patients following MRI examinations could be a way forward to halt the generally increasing concentrations of Gd in drinking water systems and recover this technologically critical element.

Corbicula fluminea: A sentinel species for urban Rare Earth Element origin.

The increase in the global population, coupled with growing consumption of Rare Earth Elements (REEs), has led to increasing transfer of these emerging contaminants into the environment, particularly through the effluents from wastewater treatment plants (WWTP). The objectives of this study were to determine the geochemical quality of a French river subject to strong urban pressure (the Jalle River in the Bordeaux area) and to examine the bioavailability of natural and anthropogenic REEs in a model species of freshwater bivalve, the Asian clam Corbicula fluminea. To this end, two fractions (dissolved and total) of the water from the Jalle River were sampled and the bivalves were exposed by in situ caging during a three-month monitoring period. The REE patterns obtained showed the presence of Gadolinium (Gd) anomalies in the dissolved and total fractions as well as in Corbicula fluminea. The apparent bioavailability of natural REEs was in the following order for the dissolved fraction: Medium REEs (MREEs) > Light REEs (LREEs) > Heavy REEs (HREEs) and for the particulate fraction: MREEs > LREEs = HREEs. These results highlight the importance of the particulate fraction in the study of the bioavailability of REEs in bivalves. An increase of anthropogenic Gd (Gdanth) was observed in the dissolved fraction between the upstream site (3.4 ng.L-1) and the WWTP Downstream site (48.4 ng.L-1). The Gd anomaly observed in the water was also observed in Corbicula fluminea with a significant increase in the bioaccumulation of Gdanth, from 1.5 ± 1 ng.gDW-1 upstream to 4.1 ± 0.7 ng.gDW-1 downstream of the WWTP effluents, thus confirming the enhanced bioavailability of medical-origin Gd to freshwater bivalves. This study strongly suggests that Corbicula fluminea can be used as a sentinel species in the monitoring of Gd contamination of medical origin. It would thus appear important to consider the potential entry of this contaminant into the human food chain via other, commercially exploited bivalve species.

Investigation of pollution levels originated from anthropogenic gadolinium in Ankara Stream.

Research on pollution caused by gadolinium (Gd) based on compounds as a result of its use in high technological applications, especially in the health sector, has recently become very interesting. This study aims to investigate the determination of the environmental pollution levels of anthropogenic Gd and its possibility of use as an anthropogenic pollutant indicator in the Ankara Stream (Turkey) selected as the pilot stream. Within the scope of the research, Gd levels were determined in water and sediment samples taken in spring and autumn periods in a total of seven different stations, three of which in Ankara Stream and one for each in its tributaries (Çubuk Stream, Hatip Stream, Incesu Creek, Ova Stream). Some parameters related to water and sediment quality were also measured at the stations. Temperature, pH, electrical conductivity, and dissolved oxygen were measured in situ. Gd concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS) technique using samples filtered from 0.45-µm filters at the time of sampling in water samples. The grain sizes of sediment samples were carried out by conventional wet sieve analysis. Gd levels were determined by ICP-MS after digestion of sediment samples passing through 63-µm particle grain size. Also, total organic carbon (TOC) and total phosphorus (TP) levels were measured by classical methods in sediment samples. Although the Gd concentrations measured in the water samples taken from the stations in the Ankara Stream were found to be quite high compared with the tributaries of Ankara Stream. The highest mean Gd concentration (0.347 ± 0.057 µg/L) measured in this study was higher than that of at the most rivers in the world. There was no statistically significant difference between the stations in terms of Gd concentrations in the sediment samples. As a result of this study, it was revealed that Gd can be used as an indicator parameter in the monitoring of anthropogenic pollution of aquatic environment where potential Gd pollution sources.

Endocrine disrupting alkylphenolic chemicals and other contaminants in wastewater treatment plant effluents, urban streams, and fish in the Great Lakes and Upper Mississippi River Regions.

Urban streams are an integral part of the municipal water cycle and provide a point of discharge for wastewater treatment plant (WWTP) effluents, allowing additional attenuation through dilution and transformation processes, as well as a conduit for transporting contaminants to downstream water supplies. Domestic and commercial activities dispose of wastes down-the-drain, resulting in wastewater containing complex chemical mixtures that are only partially removed during treatment. A key issue associated with WWTP effluent discharge into streams is the potential to cause endocrine disruption in fish. This study provides a long-term (1999-2009) evaluation of the occurrence of alkylphenolic endocrine disrupting chemicals (EDCs) and other contaminants discharged from WWTPs into streams in the Great Lakes and Upper Mississippi River Regions (Indiana, Illinois, Michigan, Minnesota, and Ohio). The Greater Metropolitan Chicago Area Waterways, Illinois, were evaluated to determine contaminant concentrations in the major WWTP effluents and receiving streams, and assess the behavior of EDCs from their sources within the sewer collection system, through the major treatment unit processes at a WWTP, to their persistence and transport in the receiving stream. Water samples were analyzed for alkylphenolic EDCs and other contaminants, including 4-nonylphenol (NP), 4-nonylphenolpolyethoxylates (NPEO), 4-nonylphenolethoxycarboxylic acids (NPEC), 4-tert-octylphenol (OP), 4-tert-octylphenolpolyethoxylates (OPEO), bisphenol A, triclosan, ethylenediaminetetraacetic acid (EDTA), and trace elements. All of the compounds were detected in all of the WWTP effluents, with EDTA and NPEC having the greatest concentrations. The compounds also were detected in the WWTP effluent dominated rivers. Multiple fish species were collected from river and lake sites and analyzed for NP, NPEO, NPEC, OP, and OPEO. Whole-body fish tissue analysis indicated widespread occurrence of alkylphenolic compounds, with the highest concentrations occurring in streams with the greatest WWTP effluent content. Biomarkers of endocrine disruption in the fish indicated long-term exposure to estrogenic chemicals in the wastewater impacted urban waterways.