Biofilms containing pathogenic organisms from the water supply are a potential source of protozoan parasite outbreaks and a significant public health concern. The aim of the present study was to demonstrate the simultaneous and multi-spatial occurrence of waterborne protozoan pathogens (WBPP) in substrate-associated biofilms (SAB) and compare it to surface water (SW) and sediments with bottom water (BW) counterparts using manual filtration and elution from low-volume samples. For scenario purposes, simulated environmental biofilm contamination was created from in-situ grown one-month-old SAB (OM-SAB) that were spiked with Cryptosporidium parvum oocysts. Samples were collected from the largest freshwater reservoirs in Luzon, Philippines and a University Lake in Thailand. A total of 69 samples (23 SAB, 23 SW, and 23 BW) were evaluated using traditional staining techniques for Cryptosporidium, and Immunofluorescence staining for the simultaneous detection of Cryptosporidium and Giardia. WBPP were found in 43% SAB, 39% SW, and 39% BW of the samples tested in the present study with SAB results reflecting SW and BW results. Further highlights were demonstrated in the potential of using low-volume samples for the detection of parasites in source water. Scanning electron microscopy of OM-SAB samples revealed a naturally-associated testate amoeba shell, while Cryptosporidium oocysts spiked samples provided a visual profile of what can be expected from naturally contaminated biofilms. This study provides the first evidence for the simultaneous and multi-spatial occurrence of waterborne protozoan pathogens in low-volume aquatic matrices and further warrants SAB testing along with SW and BW matrices for improved water quality assessment strategies (iWQAS).

The objectives of this research are: identify the hydrocarbons in water from the Bitzal River, Tabasco; select a carbon source that serves as a representative substrate of the determined compounds; and finally, design an experimental proposal for bioreactors that are capable of consuming compounds formed by complex mixtures and, therefore be effective in the elimination of specific hydrocarbons. We identified 16 compounds that belong to different hydrocarbon fractions. Pentacene (24.3 ± 0.09 mg L⁻¹), n-nonane (2.11 ± 0.96 mg L⁻¹) and benzo [a] pyrene (1.39 ± 0.57 mg L⁻¹) were the compounds with the highest concentrations in water. Two culture media, mineral medium and seawater were used. Diesel and Mayan crude oil were used for each culture medium, with a total of four bioreactors. Diesel represented light- and medium-fraction hydrocarbons, while Mayan crude oil represented the heavy fraction as well as the recalcitrant and polycyclic aromatic hydrocarbons (PAH). The maximum growth of suspended solids for diesel in mineral medium reached 2.95 g L⁻¹, and diesel was completely consumed in 8 days. In seawater, suspended solids for diesel reached 2.70 g L⁻¹, and diesel was consumed in 12 days. For Mayan crude oil in mineral medium, suspended solids increased from 0.8 to 2.41 g L⁻¹, and Mayan crude oil was completely consumed in 12 days. Using seawater, Mayan crude oil also degraded in 12 days, and suspended solids growth reached 2.11 g L⁻¹. Compounds that simulate complex mixtures of hydrocarbons from light to heavy fractions could be degraded, and the use of bioreactors is an alternative method of hydrocarbon pollution remediation in the Bitzal River.

Health and longevity are common human goals, and environmental factors can have significant impacts on human health. This study aims to investigate the historical changes and sources of trace elements in the sediments of a typical karstic river basin with high longevity population in Hechi City, Guangxi, China and to evaluate the ecological risks of trace elements in sediments. The results showed that over the past 100 years, the contents of trace elements in the sediments were lower in the upper reaches than in the middle and lower reaches of the river. The sediments had high trace element contents in 1950–1959 and 1989–1998, while low contents appeared after 1998. These periods correspond to China’s industrial growth in the early 1950s, the Great Leap Forward movement in the late 1950s, the reform and opening-up policy implemented in the 1980s–1990s and the environmental protection policies to strengthen pollution control that have been implemented since 2000. Limestone soil and carbonate rock are the main sources of sediment in the basin. Although the geological background values of Cd and other trace elements in the basin were relatively high, the high calcium content and alkalinity of the water and sediment in the basin reduced the bioavailability of Cd and other heavy metals. The mainstream of Panyang River had a low environmental risk, but the tributary Bama River where there is dense population poses a moderate risk.

Cadmium (Cd) is a well-characterized toxic heavy metal which could cause severe kidney injury. However, currently the knowledge of Cd toxicity towards kidney is still insufficient. Our previous data has identified that MT1DP (metallothionein 1D pseudogene) could promote Cd-induced detrimental effects on hepatocytes. Herein, we further found that MT1DP was also an important intermediate to aggravate Cd-induced nephrotoxicity. Through analyzing the data of 100 residents from Cd-contaminated area in Southern China, we found that the blood MT1DP levels correlated to the urine Cd content and the extent of nephrotoxicity. Although MT1DP was predominantly induced by hepatocytes in the liver, liver-secreted MT1DP was found to be packaged into extracellular cargoes: exosomes, by which MT1DP was delivered into circulation and thereafter targeted kidney cells. Furthermore, exosome-laden MT1DP worsened Cd-induced nephrotoxicity, as evidenced in both Cd-poisoned individuals and in vitro cells. Moreover, MT1DP was found to reinforce Cd-induced toxicity in kidney cells by indirectly breaking the equilibrium between the pro-apoptotic and anti-apoptotic effects conducted by BAX and Bcl-xL, respectively. Collectively, our data unveiled that hepatocyte-derived MT1DP depends on the delivery of exosomes to wreak considerable havoc in Cd nephrotoxicity. This study offers new insights into the molecular mechanisms of Cd-induced kidney injury.

Spirotetramat, a member of tetronic and tetramic acid derivatives, is a unique insecticide and acaricide. Although the effect on zebrafish embryos lipid biosynthesis of spirotetramat has been characterized, the energy metabolism and toxic effect mechanism warrant further investigation. To investigate the toxic mechanism of spirotetramat on energy metabolism, zebrafish embryos were exposed to 100, 500 and 1000 µg/L of spirotetramat for 4 days. Untargeted metabolomics showed the synthesis and degradation of ketone pathway metabolites (R)-3-Hydroxybutyric acid and Acetoacetate significantly decreased, as well as increasing the abundance of Anti-Acetyl Coenzyme A Carboxylase protein (ACC1). Down-regulation of the genes related to ß-oxidation and the tricarboxylic acid cycle in the embryos show decreased energy metabolism. Carnitine palmitoyltransferase 1 (CPT- I) significantly decreased while citrate synthase (CS) significantly increased. Additionally, mitochondrial lesions in embryos were found using electron microscopy. Our study provides novel and robust perspectives, which show that spirotetramat treatment in embryos leads to metabolic disturbances that adversely affect cellular energy homeostasis.

Potentially toxic elements (PTEs) are of major concern due to their high persistence and toxicity. Recently, rare earth elements (REEs) concentration in aquatic ecosystems has been increasing due to their application in modern technologies. Thus, this work aimed to study, for the first time, the influence of REEs (lanthanum, cerium, praseodymium, neodymium, europium, gadolinium, terbium, dysprosium and yttrium) and of salinity (10 and 30) on the removal of PTEs (Cd, Cr, Cu, Hg, Ni and Pb) from contaminated waters by living macroalgae (Fucus spiralis, Fucus vesiculosus, Gracilaria sp., Osmundea pinnatifida, Ulva intestinalis and Ulva lactuca). Experiments ran for 168 h, with each macroalga exposed to saline water spiked with the six PTEs and with the six PTEs plus nine REEs (all at 1 μmol L⁻¹) at both salinities. Results showed that all species have high affinity with Hg (90–99% of removal), not being affected neither by salinity changes nor by the presence of other PTEs or REEs. Cd showed the lowest affinity to most macroalgae, with residual concentrations in water varying between 50 and 108 μg L⁻¹, while Pb removal always increased with salinity decline (up to 80% at salinity 10). REEs influence was clearer at salinity 30, and mainly for Pb. No substantial changes were observed in Ni and Hg sorption. For the remaining elements, the effect of REEs varied among algae species. Overall, the results highlight the role of marine macroalgae as living biofilters (particularly U. lactuca), capable of lowering the levels of top priority hazardous substances (particularly Hg) and other PTEs in water, even in the presence of the new emerging contaminants - REEs. Differences in removal efficiency between elements and macroalgae are explained by the contaminant chemistry in water and by macroalgae characteristics.

In February 2014, the coalmine adjacent to the Hazelwood Power Station in the Latrobe Valley of Victoria, Australia, caught fire, with residents from the nearby town of Morwell and the wider area exposed to smoke for six weeks. Although there was evidence linking the mine-fire event with psychological distress, no studies have evaluated the degree of distress in relation to the level of smoke exposure. We aimed to investigate the exposure-response relationship between particulate matter 2.5 μm or less in diameter (PM₂.₅) released during the Hazelwood mine fire event and long-term symptoms of posttraumatic distress in the affected community, including the consideration of other key factors. A total of 3096 Morwell residents, and 960 residents from the largely unexposed comparison community of Sale, were assessed for symptoms of posttraumatic distress 2.5 years after the Hazelwood incident using the Impact of Events Scale-Revised (IES-R). Individual-level PM₂.₅ exposure was estimated by mapping participants’ self-reported location data on modelled PM₂.₅ concentrations related to the mine fire. Multivariate linear regression was used to evaluate the exposure-response relationship. Both mean and peak exposure to mine fire-related PM₂.₅ were found to be associated with participant IES-R scores with an interaction effect between age and mean PM₂.₅ exposure also identified. Each 10 μg/m³ increase in mean PM₂.₅ exposure corresponded to a 0.98 increase in IES-R score (95% CI: 0.36 to 1.61), and each 100 μg/m³ increase in peak PM₂.₅ exposure corresponded to a 0.36 increase (95% CI: 0.06 to 0.67). An age-effect was observed, with the exposure-response association found to be stronger for younger adults. The results suggest that increased exposure to PM₂.₅ emissions from the Hazelwood mine fire event was associated with higher levels of psychological distress associated with the mine fire and the most pronounced effect was on younger adults living in the affected community.

Cerium oxide (CeO2) nanoparticles are used as in-fuel catalysts and in manufacturing processes, creating a potential for release to aquatic environments. Exposures at 1 and 10 μg/L CeO2-nanoparticles were made to assess effects during the development of river biofilm communities. Scanning transmission x-ray microscopy (STXM) indicated extensive sorption of nanoparticles to the community and co-localization with lipid moieties. Following 8 weeks of development, polycarbonate coupons were removed from the reactors and used for molecular analyses, denaturing gradient gel electrophoresis analysis (DGGE-16S rRNA) and 16S rRNA amplicon sequencing. Microscopic imaging of the biofilm communities (bacterial, photosynthetic biomass, exopolymer composition, thickness, protozoan numbers), as well as carbon substrate utilization fingerprinting was performed. There was a trend toward reduced photosynthetic biomass, but no significant effects of CeO2 exposure were found on photosynthetic and bacterial biomass or biofilm thickness. Sole carbon source utilization analyses indicated increased utilization of 10 carbon sources in the carbohydrate, carboxylic acid and amino acids categories related to CeO2 exposures; however, predominantly, no significant effects (p < 0.05) were detected. Measures of microbial diversity, lectin binding affinities of exopolymeric substances and results of DGGE analyses, indicated significant changes to community composition (p < 0.05) with CeO2 exposure. Increased binding of the lectin Canavalia ensiformis was observed, consistent with changes in bacterial-associated polymers. Whereas, no significant changes were observed in binding to residues associated with algal and cyanobacterial exopolymers. 16S rRNA amplicon sequencing of community DNA indicated changes in diversity and shifts in community composition; however, these did not trend with increasing CeO2 exposure. Counting of protozoans in the biofilm communities indicated no significant effects on this trophic level. Thus, based on biomass and functional measures, CeO2 nanoparticles did not appear to have significant effects; however, there was evidence of selection pressure resulting in significant changes in microbial community composition.

The microparticle content of 37 common facial and body scrubs commercially available in the United Arab Emirates was analyzed. The chemical composition, ash content, physical characteristics, loading, particle size and shape of the microparticles were determined. Only 11 out of 37 products were found to have microplastic content. Many of the remaining products exhibited microparticles composed of microcrystalline cellulose and crushed walnut shells. Differential scanning calorimetry showed that microplastic products had softening points as low as 84 °C. Plastic microbeads of 2 products were found to fuse at 100 °C. The fusion altered the flotation characteristics of the microbeads of one product. Heat treatment of the product at 100 °C in the presence of silica gel led to entrainment of the silica and partial fragmentation of the beads upon cooling. This may be understood as one mechanism of fragmentation of a microplastic with a low softening point in the presence of hard soil particles under temperature cycling.

Microplastic pollution is widespread across most ocean basins around the world. Microplastics (MPs) are small plastic particles that have a significant impact on the marine environment. Various research on plastic pollution have been conducted in several regions. However, currently, there is limited data on the distribution and concentration of MPs in the mid-west Pacific Ocean. Therefore, this study we investigated the abundance, distribution, characteristics, and compositions of MPs in this region. Sea surface water samples collected from 18 stations showed a microplastic concentration range of 6028–95,335 pieces/km² and a mean concentration of 34,039 ± 25,101 pieces/km². Highest microplastic concentrations were observed in the seamount region of western Pacific. We observed a significant positive correlation between microplastic abundance and latitude across the study region. It was observed that microplastic concentrations decreased with increasing offshore distance at sites located on a 154° W transect. Fibres/filaments were the dominant microparticles observed in this study (57.4%), followed by fragments (18.3%). The dominant particle size range was 1–2.5 mm (35.1%), followed by 0.5–1 mm (28.5%), and the dominant particle colour was white (33.8%), followed by transparent (31.0%) and green (24.6%). The most common polymer identified by μ-Raman was polypropylene (39.1%), followed by polymethyl methacrylate (16.2%), polyethylene (14.1%) and polyethylene terephthalate (14.2%). The possible sources and pathways of microplastics in the study area were proposed based on the morphological and compositional characteristics of particles, their spatial distribution patterns, and shipboard current profiling (ADCP). Our study contributes to the further understanding of MPs in remote ocean areas.