Important Source Of Contamination Research Articles

Imprints of wastewater discharge on trace element dynamics in the Grand River, Ontario.

Discharge of treated wastewater effluent can be an important source of contaminants to downstream environments, but only a handful of specific effluent parameters are regulated and monitored in Canada. Consequently, the importance of effluent discharge for the surface water budgets of trace elements remains poorly understood. Here, we report concentrations of > 50 major and trace elements in > 30 riverine and effluent samples collected in the Grand River catchment, Ontario, in an attempt to assess imprints of effluent discharge on riverine trace element loads. We find that effluent-derived loads of major and trace elements generally outweigh those of tributaries when contrasted to their hydraulic contribution at the point of confluence. In particular, effluent-derived loads of conservative elements (> 30-fold the receiving riverine load), but also those of heavy metals and rare earth elements (> tenfold and twofold their receiving riverine loads, respectively) exerted important controls on trace element dynamics in the Grand River. Yet, multiple elemental tracers suggest that detectable imprints of these trace element inputs remain spatially restricted and limited to the catchment's upper reaches, urban areas, and confluences and effluent inputs with low mixing ratios. This study presents important baseline data for trace elements in this complex river system and highlights the need for expanded surface water quality monitoring to disentangle anthropogenic from natural factors affecting trace element budgets.

Water quality information for farmer decision making in the Nguturoa catchment, Manawatu

In 2021 a group of farmers and landowners along the Nguturoa Stream in the Manawatū-Whanganui Region began a study into water quality. The farmers felt that they needed precise information to establish their farming priorities for improving the waterway, and for monitoring the effects of making management changes. Monthly sampling and laboratory testing were carried out across the catchment and field tests werealso undertaken at the time of sampling. The results were compared to those in the Manawatū River, the ultimate receiving environment for the catchment. The results highlighted that throughout the year the water in the Nguturoa Stream had lower dissolved inorganic nitrogen concentrations than the Manawatū River, but it had higher organic nitrogen concentrations in most months. Almost all the phosphorus results were above those measured in the Manawatū River as were the turbidity results. On seven occasions the Nguturoa Stream had E.coli results above the standard in the National Policy Statement for Freshwater Management 2020. Compared to the laboratory test results, the fieldtests that were used were found to be inconsistent and unreliable for catchment and farm management decision making. The results highlighted for the farmers that overland flow was a more important source of instream contamination than they expected, for nitrogen,phosphorus and E.coli as well as sediment.

Assessment of trace element content throughout the white shrimp (Litopenaeus vannamei) farming cycle

Environmental context Intensive aquaculture is the main source of fisheries products. Thus, investigating the food safety of these products and the environmental impacts of the farms on mangroves is necessary. A shrimp productive cycle was evaluated with a focus on trace element accumulation in shrimps and effluent. The results revealed secure levels of elements in the final product; however, the effluent produced in farms is an important source of contamination to mangrove environment. Rationale Aquaculture systems have increased in the last years due to the high demand for seafood consumption, this could impact the environment and subject fisheries to accumulation of toxic elements. To understand some parameters of food safety and environmental impact, the present study evaluated the concentration of trace elements (Al, As, Cd, Co, Cr, Cu, Mn, Mo, Pb, Se, V and Zn) throughout the production cycle of shrimp. Methodology About 50 shrimps per cycle were collected in a shrimp farm in Brazil and their trace element contents were determined by inductively coupled plasma–tandem mass spectrometry (ICP-MS/MS) and microwave-induced plasma–optical emission spectroscopy (MIP-OES). Results At their final lifecycle stage, shrimp samples present a content (mg g−1) of elements following the trend: Cu (102 ± 12) > Al (20.06 ± 4.24) > Zn (14.82 ± 2.46) > Mn (6.24 ± 0.94) > As (2.65 ± 0.42) > Se (0.932 ± 0.140) > Co (0.380 ± 0.05) > Mo (0.254 ± 0.03) > V (0.204 ± 0.02). Discussion The content of Cd and Pb are in allowance with Brazil and USA legislation for crustaceans, however, the content of As is 3–4-fold higher than that allowed by guidelines in all stages of the growth of the shrimp. The final effluent of the shrimp’s pond into the mangroves shows a high mass fraction of Zn and Mn that could be a source of contamination. Some correlations between some elements in the shrimp samples were found, such as As–Se, Se–Co and Se–V. This study was a scoping experiment to study the content of trace elements throughout the farming cycle of shrimps, encouraging the researcher to undergo a wide survey to evaluate the environmental impact of aquaculture shrimp farming.

Geographical distribution of Aspergillus flavus in peanut harvest period in China

In order to grasp the distribution of Aspergillus flavus in the soil of peanut production areas in China, A. flavus biomarkers were tested on 555 soil samples from 37 sampling points in 17 provinces, peanut fields in four agroecological zones (Southern area, Yangtze River Basin, Northern area, Northeast area). The results showed that (1) the cultivation amount of A. flavus per gram of soil in the Yangtze River Basin is 1.30 times that of the southern area, 1.56 times that of the northern area, and 6.20 times that of the northeast area, with obvious regional characteristics. (2) In the Yangtze River basin, the change of longitude in the east-west direction has no direct impact on the cultivation amount of A. flavus per gram of soil. (3) In the east coast, the A. flavus cultivated per gram of soil increased first and then decreased with the increase of latitude from south to north. (4) A. flavus can be isolated in the soil samples above 1000 ​m. Field pollution is an important source of aflatoxin contamination in peanut. The study on the distribution of A. flavus in soil in China could provide theoretical support for the early warning and prevention and control measures of aflatoxin contamination in peanut.

Cadmium concentrations in hair in the population of the subjects of the Russian Federation: a systematic review

Cadmium (Cd) is one of the most toxic trace elements. The most important sources of Cd contamination by burning fossil fuels as coal or oil and incineration of urban waste, including plastics and nickel-cadmium batteries. In all countries these sources make Cd contamination an important health issue worldwide. Cd can enter the body through smoking tobacco, eating and drinking food and water polluted with Cd, and breathong. Cd concentration in human hair, nails and blood is considered as an indicator of environmental pollution. However, there is little systemized information on Cd concentration in human tissues in Russia. This is a systematic review following PRISMA guidelines. We performed a systematic search and qualitative synthesis of scientific literature on Cd concentrations in hair across Russia between 2011 and 2021. PubMed and e-library were the main sources of scientific information in English and Russian, respectively. Initial search returned 1202 matches. Twenty-nine papers remained for qualitative synthesis after screening and eligibility analysis. Studies on Cd concentrations were performed in only 19 of 85 federal subjects (22.4%). No heterogeneity was observed in sample preparation while methods of laboratory analysis varied between the settings and included inductively coupled plasma mass spectrometry, atomic absorption spectrometry, and inversion voltammetry. The sample sizes ranged from 12 to 5908 individuals. The average Cd concentrations varied from 0.010 mg/kg to 0.164 mg/kg. The greatest concentrations of Cd were reported from Sibai in the Orenburg Region (0.164 mg/kg), in indigenous people of the Yamalo-Nenets Autonomous Okrug (0.15 mg/kg) and in residents of the Arctic part of the Sakha Republic (0.14 mg/kg); The maximum values on the abovementioned regions were 7.02 mg/kg, 0.52 mg/kg, and 0.51 mg/kg. High maximum concentrations were also found in the Republic of Bashkortostan (0,9 mg/kg) and in Yaroslavl (0,37 mg/kg). Conclusion. Data on Cd concentrations in human hair from 66 federal subjects are still needed for mapping of Cd concentration in Russia. Further data collection should be performed using representative and sufficient sample samples while presentation of the results should contain detailed information on methods of data collection and analysis to ensure reproducibility and comparability of the findings.

Alkylated phosphorylated fibers: A new substitute for silicone in release paper manufacturing

The production of release coatings has been increasing in recent years because of their use in various fields. However, commercially available release coatings are regarded as non-recyclable. As a consequence, the repulping of these residues is difficult, and their presence in the recycling stream represents an important source of contamination. One solution to this problem is to use new coating materials that can replace the siliconized backing, provided that these new materials are recyclable. As a solution to this problem, the authors propose the use of alkylated phosphorylated fibers to produce an environmentally friendly and inexpensive release paper. The results show that a surface application of hydrophobic phosphorylated fibers reduces the surface free energy of the paper support, as well as the peel strength, which facilitates the separation of the adhesive tape.

Isotopic (Cu, Zn, and Pb) and elemental fingerprints of antifouling paints and their potential use for environmental forensic investigations

Antifouling paints (APs) are one of the important sources of Cu and Zn contamination in coastal environments. This study applied for the first-time a multi-isotope (Cu, Zn, and Pb) and multi-elemental characterization of different AP brands to improve their tracking in marine environments. The Cu and Zn contents of APs were shown to be remarkably high ∼35% and ∼8%, respectively. The δ65CuAE647, δ66ZnIRMM3702, and 206Pb/207Pb of the APs differed depending on the manufacturers and color (−0.16 to +0.36‰, −0.34 to +0.03‰, and 1.1158 to 1.2140, respectively). A PCA analysis indicates that APs, tires, and brake pads have also distinct elemental fingerprints. Combining isotopic and elemental ratios (e.g., Zn/Cu) allows to distinguish the environmental samples. Nevertheless, a first attempt to apply this approach in highly urbanized harbor areas demonstrates difficulties in source apportionments, because the sediment was chemically and isotopically homogeneous. The similarity of isotope ranges between the harbor and non-exhaust traffic emission sources suggests that most metals are highly affected by urban runoff, and that APs are not the main contributors of these metals. It is suspected that AP-borne contamination should be punctual rather than dispersed, because of APs low solubility properties. Nevertheless, this study shows that the common coastal anthropogenic sources display different elemental and isotopic fingerprints, hence the potential for isotope source tracking applications in marine environments. Further study cases, combined with laboratory experiments to investigate isotope fractionation during releasing the metal sources are necessary to improve non-traditional isotope applications in environmental forensics.

Presence of pharmaceuticals and bacterial resistance genes in river epilithic biofilms exposed to intense agricultural and urban pressure

The continuous discharge of pharmaceutical compounds into the aquatic environment has raised concerns over the contamination of water resources. Urban activities and intensive animal breeding are important sources of contamination. The accumulation of antibiotics may lead to the transfer or alternatively maintain the presence of resistance genes in natural microbial communities existing in epilithic biofilms. The objective of this study was to evaluate the pharmaceutical contamination levels and the presence of resistance genes in biofilms from a South Brazilian watershed. The Guaporé watershed exhibits a high diversity of land use, including agricultural and urban areas with differing levels of anthropogenic pressure. Seventeen sites along the Guaporé watershed were monitored. Biofilm samples were collected in two seasons (winter and summer), and the pharmaceutical concentration and quantity of resistance genes were analyzed. All monitored sites were contaminated with pharmaceuticals. Agricultural activities contribute through transferring pharmaceuticals derived from the application of animal waste to agricultural fields. The most contaminated site (pharmaceuticals and bacterial resistance genes) was located in an urban area exposed to high pressure. Decreases in the contamination of biofilms were also observed, exemplifying processes of natural attenuation in the watershed. The quality of the biofilms sampled throughout the watershed served as a useful tool to understand and monitor environmental pollution.

Prevalence of pleuromutilin antibiotic resistance genes in different laying hen breeding stages in China.

Antimicrobial resistance is a rapidly evolving and extremely complex issue, particularly due to the use of various types of antimicrobials within human, animal, and environmental sectors. Pleuromutilin antibiotics are used to prevent and control respiratory diseases in the rearing stage of hen chicks, but the current status of pleuromutilin resistance in the laying hen breeding process is unclear. ATP-binding cassette transporters encoded by lsa(A), lsa(E), lsa(C), and vga(D) can be transferred by plasmids and transposons, thereby posing a potential dissemination risk. To investigate pleuromutilin resistance genes in the laying hen production chain in China, 95 samples from five environmental types were collected in four breeding stages to determine the abundances of the main resistance genes by qPCR, i.e. lsa(A), lsa(E), lsa(C), and vga(D). The abundance (5.16 log10GC/g) and detection rate (100%) of lsa(E) was highest in all of the samples, thereby suggesting high contamination with the lsa(E) gene across the large-scale laying hen breeding environment and feces. The lsa(A) (6.02 log10GC/g) and lsa(E) (6.18 log10GC/g) genes were most abundant in flies, and the abundance of vga(D) (4.50 log10GC/g) was highest in dust (P<.05). In addition to feces, flies and dust were important sources of contamination with pleuromutilin resistance along the laying hen production chain. In summary, we determined the abundances of four pleuromutilin resistance genes in the laying hen production chain and provided direct evidence of pleuromutilin resistance transmission and environmental contamination. In particular, the chicken breeding stage needs further attention.

Full-Scale O3/Micro-Nano Bubbles System Based Advanced Oxidation as Alternative Tertiary Treatment in WWTP Effluents

Wastewater treatment plant effluents can be an important source of contamination in agricultural reuse practices, as pharmaceuticals are poorly degraded by conventional treatments and can enter crops, thereby becoming a toxicological risk. Therefore, advanced tertiary treatments are required. Ozone (O3) is a promising alternative due to its capacity to degrade pharmaceutical compounds, together with its disinfecting power. However, mass transfer from the gas to the liquid phase can be a limiting step. A novel alternative for increased ozone efficiency is the combination of micro-nano bubbles (MNBs). However, this is still a fairly unknown method, and there are also many uncertainties regarding their implementation in large-scale systems. In this work, a combined O3/MNBs full-scale system was installed in a WWTP to evaluate the removal efficiency of 12 pharmaceuticals, including COVID-19-related compounds. The results clearly showed that the use of MNBs had a significantly positive contribution to the effects of ozone, reducing energy costs with respect to conventional O3 processes. Workflow and ozone production were key factors for optimizing the system, with the highest efficiencies achieved at 2000 L/h and 15.9 gO3/h, resulting in high agronomic water quality effluents. A first estimation of the transformation products generated was described, jointly with the energy costs required.

FOUNTAINE WATER POTABILITY ASSESSMENT IN THE SUCEAVA COUNTY

Due to the qualitative changes of groundwater, produced by pollution with substances that alter the physical, chemical and biological qualities of water, at the level of individual water sources (wells), there are frequently recorded exceedances of the maximum permissible concentration for chemical parameters such as ammonium, nitrates, nitrites, hardness, etc.&#x0D; The quality of water in wells is influenced by the soil structure and various sources of pollution and the excessive use of fertilizer for fertilization and also by rain washing of agricultural soils (especially in winter). The presence of severe storms can be important sources of nitrate contamination for surface waters. Even the natural structure of the soil can alter the quality of the water.&#x0D; Increased concentrations of nitrate in drinking water can be produced by several sources already mentioned, but also by the non-compliance with hygienic-sanitary conditions and location of wells. The goal of this study is to increase the awareness of the importance of monitoring the quality of the water that people consumes. Systematic monitoring of the quality of drinking water is essential, considering the negative influence of the exceedence of maximum admissible values for some parameters, especially on the organisms of children and infants for whom can even lead to death. The results show that the maximum admissible limit values for nitrate and ammonium concentrations in the fountaine water from the Suceava district are exceeded in some cases, while the other parameters under investigation are in general within the permissible limits.

Post-wildfire contamination of soils and sediments by polycyclic aromatic hydrocarbons in north-central British Columbia, Canada

Background The Nechako River Basin (NRB) is a large, regulated basin in north-central British Columbia, Canada that has been impacted by numerous landscape disturbances, including a severe wildfire in 2018. Aims The aims of this study were to quantify the post-wildfire temporal and spatial extent of contamination by polycyclic aromatic hydrocarbons (PAHs) of both soils and riverine sediments, and to identify the primary sources of PAHs in the watershed. Methods Soil samples were collected at burned and unburned sites in 2018 and at the burned sites in 2020 and 2021. Sediment samples were collected at three tributaries impacted by wildfire and three Nechako River mainstem (i.e. main channel) sites from 2018 to 2021. Samples were analysed for parent PAHs. Key results PAH concentrations decreased in soil samples from 2018 to 2021 but are not below the concentrations found in unburned samples. Tributary sediment samples showed higher concentrations immediately post-fire relative to the mainstem Nechako River, but in the years since, that trend has reversed. Conclusions PAHs persist in terrestrial and aquatic environments for years following wildfire, but at concentrations below various quality guidelines. PAHs were primarily derived from the wildfires, with some mixed sources at the downstream sites. Implications Wildfires are an important source of environmental contamination of terrestrial and aquatic environments.

A study on the impact of harvesting operations on the mineral oil contamination of olive oils

During the 2020–21 olive oil campaign, the contribution of harvesting operations to mineral oil saturated (MOSH) and aromatic hydrocarbon (MOAH) contamination was studied. Oils extracted from hand-picked olives (15 different olive groves) generally had background MOSH (<2.7 mg/kg), and no quantifiable MOAH. In 40% of the cases, an important contamination increase was observed after harvesting operations. Except for one sample (325.8 and 111.0 mg/kg of MOSH and MOAH, respectively), other samples reached 4.3–33.7 mg/kg of MOSH and 1.1–11.3 mg/kg of MOAH. Accidental leaks of lubricants and/or contact with lubricated mechanical parts, were identified as important sources of contamination. Chromatographic traces obtained by on-line high-performance liquid chromatography (HPLC)-gas chromatography (GC)-flame ionization detection (FID) allowed for source identification. A comprehensive two-dimensional gas chromatographic platform (GC × GC) with parallel FID/MS detection was implemented for confirmation and to attempt the characterization of the contaminations. Good harvesting practices are suggested to minimize contamination risks.

Promising strategies of circular bioeconomy using heavy metal phytoremediated plants – A critical review

Phytoremediation is an excellent method for removing harmful heavy metals from the environment since it is eco-friendly, uses little energy, and is inexpensive. However, as phytoremediated plants can turn into secondary sources for heavy metals, complete heavy metal removal from phytoremediated plants is necessary. Elimination of toxic heavy metals from phytoremediated plants should be considered with foremost care. This review highlights about important sources of heavy metal contamination, health effects caused by heavy metal contamination and technological breakthroughs of phytoremediation. This review critically emphasis about promising strategies to be engaged for absolute reutilization of heavy metals and spectacular approaches of production of commercially imperative products from phytoremediated plants through circular bioeconomy with key barriers. Thus, phytoremediation combined with circular bioeconomy can create a new platform for the eco-friendly life.

Prevalence of Intestinal Parasites in Dog Faecal Samples from Public Environments in Qinghai Province, China

Dogs are popular companions in our daily lives for company, hunting, protection or shepherding, but they also serve as reservoirs for zoonotic parasites. We analysed faecal samples from urban and rural environments in Qinghai Province on the Qinghai-Tibet Plateau of China to determine the prevalence of intestinal parasites. A total of 682 faecal samples were collected from four urban and two rural environments from October 2019 to December 2020. The samples were analysed for common intestinal parasites using a species-specific PCR approach. The total number of samples with parasites was 40 (5.87%): 23 (3.37%) were positive for helminths, and 17 (2.49%) were positive for protozoa. The following parasites were identified, and their respective prevalence rates were calculated: Cryptosporidium canis (1.32%), Giardia duodenalis (1.17%, assemblages D (n = 6) and C (n = 2)), Taenia hydatigena (1.03%), Taenia multiceps (0.59%), Toxocara canis (0.59%), Echinococcus shiquicus (0.29%), Dipylidium caninum (0.29%), Taenia pisiformis (0.15%), Mesocestoides lineatus (0.15%), Trichuris vulpis (0.15%), and Ancylostoma spp. (0.15%). The overall prevalence was significantly higher in dog faecal samples from rural environments than in those from urban environments (16.19% vs. 3.99%). E. shiquicus, T. pisiformis, M. lineatus, T. vulpis, and Ancylostoma spp. were only found in dog faecal samples from rural environments. The results of the present study indicate that intestinal parasite-positive dogs are important sources of environmental contamination, suggesting a significant zoonotic infection risk in humans and other animals. This has implications for the ongoing control of intestinal parasite infections in dogs in Qinghai Province, China.

Impact of the visitor walking speed and glass barriers on airflow and Bioaerosol particles distribution in the typical open tomb

With the rapid development of modern tourism, the contamination of cultural heritage including human spiritual civilization by visitors has increased, particularly for precious murals. In this study, the Bioaerosol Particles in air were found to be an important source of contamination on murals by internal transcribed spacer rRNA gene-based sequences. Moreover, computational fluid dynamics was applied to further study the influence of visitor walking speed on airflow and Bioaerosol Particles distribution in a typical open tomb. The accuracy of the results was verified by field experiments, including environmental parameter monitoring and Bioaerosol Particles collection. The fairly mature Omega vortex identification method was introduced to analyse the airflow changes and Bioaerosol Particles migration as the visitor walked at three different speeds. Furthermore, the effects of glass barriers were evaluated neutrally. The results showed that the Bioaerosol Particles migrated around the visitor while walking, contaminating the murals. After walking, the number of Bioaerosol Particles deposited on murals increased and was approximately positively correlated with walking speed. The amount of Bioaerosol Particles deposited decreased significantly when barriers were installed near the walls. This study provides a reference for the sustainable protection and inheritance of the history and civilization of mankind in modern cities.

Priority screening of contaminant of emerging concern (CECs) in surface water from drinking water sources in the lower reaches of the Yangtze River based on exposure-activity ratios (EARs)

Surface water provides ecological services such as drinking water supply. However, contaminants of emerging concern (CECs) are rising concerns because they are ubiquitously detected in surface water and pose potential risks to the aquatic environment and human health. This study investigated the occurrence of 165 CECs in surface water from drinking water source areas along the lower reaches of the Yangtze River to prioritize the CECs and to estimate potential biological activity based on exposure-activity ratio (EAR). A total of 70 CECs were detected in the surface water at least once at the selected 17 sampling sites, and their concentrations ranged from 0.592 to 4650 ng/L. Twenty-four CECs were detected at each site, and these were mostly pharmaceutical and personal care products and pesticides. Sucralose, 1H-benzotriazole and carbendazim were the most common CECs with high median concentrations in the study area. Specifically, sucralose, an artificial sweetener, was presented at each site with the highest median concentration (3010 ng/L), which indicated that anthropogenic inputs are an important source of contaminants. Medroxyprogesterone and trenbolone were identified as the priority contaminants of interest, with maximum EARchemical values of 0.389 and 0.183, respectively. Among all the sites, the higher cumulative EARmixture value was found from Nantong City (0.765), which indicated that this site could have a relatively greater potential for biological effects, and these effects were mainly due to medroxyprogesterone and trenbolone. In regard to the bioactivity of all detected CECs, nuclear receptors showed the greatest potential bioactivity in this region, particularly androgen receptor-mediated bioactivity, which is most likely affected organisms residing in the source water area. These results suggest that the drinking water sources from the studied region are contaminated with CECs, and highlight the prioritization of future monitoring and research to protect source waters.

Mycotoxins Contamination in Rice: Analytical Methods, Occurrence and Detoxification Strategies.

The prevalence of mycotoxins in the environment is associated with potential crop contamination, which results in an unavoidable increase in human exposure. Rice, being the second most consumed cereal worldwide, constitutes an important source of potential contamination by mycotoxins. Due to the increasing number of notifications reported, and the occurrence of mycotoxins at levels above the legislated limits, this work intends to compile the most relevant studies and review the main methods used in the detection and quantification of these compounds in rice. The aflatoxins and ochratoxin A are the predominant mycotoxins detected in rice grain and these data reveal the importance of adopting safety storage practices that prevent the growth of producing fungi from the Aspergillus genus along all the rice chain. Immunoaffinity columns (IAC) and QuECHERS are the preferred methods for extraction and purification and HPLC-MS/MS is preferred for quantification purposes. Further investigation is still required to establish the real exposition of these contaminants, as well as the consequences and possible synergistic effects due to the co-occurrence of mycotoxins and also for emergent and masked mycotoxins.

Effects of aqueous extracts of wildfire ashes on tadpoles of Pelophylax perezi: Influence of plant coverage

Wildfires have been pointed out as an important source of diffuse contamination to aquatic ecosystems, namely through the input of toxic compounds such as polycyclic aromatic hydrocarbons and metals. However, amphibians' responses to this disturbance have been largely ignored. Hence, this study intended to assess how ashes from Pinus sp. and Eucalyptus sp. plantation forests affect tadpoles of Pelophylax perezi. Tadpoles were exposed 14 days to serial concentrations (26.9 %–100 %) of aqueous extracts of ashes (AEA, with 10 g L−1 of ashes) containing Eucalypt (ELS) and Pine (PLS) ashes. The following endpoints were measured: mortality, malformations, developmental stage, body length and weight. Effects at sub-individual level were also monitored for oxidative stress, neurotoxicity, and energetic metabolism. Chemical characterization of the AEA of ELS showed higher concentrations of As, Cd, Co, Cr, Pb and V, while PLS showed higher concentrations of Cu, Mn, Ni and Zn. Concerning the lethal effects of AEAs on tadpoles, both extracts were able to induce mortality at high concentrations (76.9 and/or 100 % of AEA), although a high variability in the response was found. A significant mortality in tadpoles exposed to ELS was observed at the concentration of 76.9 %. For organisms exposed to PLS, though a mortality above 20 % was registered at the two highest tested concentrations, it was not significantly different from the control. No significant sub-lethal effects were observed in the ELS treatments. Contrasting, exposure to PLS induced a decrease in body length, weight, glutathione-S-transferase activity and an increase in oxygen consumption. Overall, the distinct effects of ELS and PLS suggest an influence of vegetation cover in ash toxicity. In conclusion, exposure to both ash extracts negatively affected sublethal responses of tadpoles of P. perezi. Future research is needed to assess how these effects at individual level may translate into effects at population level.

Hydroxyl-radical based advanced oxidation processes can increase perfluoroalkyl substances beyond drinking water standards: Results from a pilot study

Advanced oxidation processes (AOPs) are popular technologies employed across the U.S. for wastewater reclamation and drinking water treatment of recalcitrant chemicals. Although there is consensus about the ineffectiveness of AOPs to treat perfluoroalkyl substances (PFASs; not polyfluoro compounds by definition here), there is a lack of field data demonstrating their impact on the transformation of unknown PFAS precursors during groundwater treatment. In this study, the fate of PFASs in seven pilot-scale AOPs, including four different technologies (UV/H2O2, UV/Cl2, UV/TiO2, and O3/H2O2), was assessed at four drinking water systems across New York State (NYS), USA. Seven of 18 PFASs were detected in the influent at concentrations ranging from below method detection to 64 ng/L. Across all systems, all detected PFASs showed an increase in concentration after treatment presumably due to unknown precursor transformation with specific increases for perfluorobutane sulfonate (PFBS), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorononanoic acid (PFNA) averaging 405 (range: 0 – 1220) %, 1.0 (-7 – 9) %, 3.8 (0 – 9.5) %, 3.3 (-11 – 13) %, 14 (0 – 48) %, 13 (3 – 25) %, and 2 (0 – 5.2) %, respectively. The increase in PFAS concentration was dependent on UV and oxidant dose, further confirming that transformation reactions were occurring due to AOPs similar to a total oxidizable precursor assay. At one of the sites, PFOA levels exceeded the current NYS drinking water standard of 10 ng/L after, but not before treatment, highlighting the importance of considering the potential impact of AOP on treated water quality when designing treatment systems for regulatory compliance. The increase in PFAS concentration in the AOP systems positively correlated (r = 0.91) with nitrate levels in groundwater, suggesting that onsite septic discharges may be an important source of PFAS contamination in these unsewered study areas. Results from this pilot-scale demonstration reveal that hydroxyl radical-based AOPs, although ineffective in treating PFASs, can help to reveal the true extent of PFAS contamination in source waters.