Low-level Contamination Research Articles

Thyroid doses in Ukraine due to 131I intake after the Chornobyl accident. Report II: dose estimates for the Ukrainian population.

This paper describes the revision of the thyroid dosimetry system in Ukraine using new, recently available data on (i) revised 131I thyroid activities derived from direct thyroid measurements done in May and June 1986 in 146,425 individuals; (ii) revised estimates of 131I ground deposition density in each Ukrainian settlement; and (iii) estimates of age- and gender-specific thyroid masses for the Ukrainian population. The revised dosimetry system estimates the thyroid doses for the residents of the settlements divided into three levels depending on the availability of measurements of 131I thyroid activity among their residents. Thyroid doses due to 131I intake were estimated in this study for different age and gender groups of residents of 30,353 settlements in 24 oblasts of Ukraine, Autonomous Republic Krym, and cities of Kyiv and Sevastopol. Among them, dose estimates for 835 settlements were based on 131I thyroid activities measured in more than ten residents (the first level), for 690 settlements based on such measurements done in neighboring settlements (the second level), and for 28,828 settlements based on a purely empirical relationship between the thyroid doses due to 131I intake and the cumulative 131I ground deposition densities in settlements (the third level). The arithmetic mean of the thyroid doses due to 131I intake among 146,425 measured individuals was 0.23Gy (median of 0.094Gy); about 99.8% of them received doses less than 5Gy. The highest oblast-average population-weighted thyroid doses were estimated for residents of Chernihiv (0.15Gy for arithmetic mean and 0.060Gy for geometric mean), Kyiv (0.13 and 0.051Gy) and Zhytomyr (0.12 and 0.049Gy) Oblasts followed by Rivne (0.10 and 0.039Gy) and Cherkasy (0.088 and 0.032Gy) Oblasts, and Kyiv City (0.076 and 0.031Gy). The geometric mean of thyroid doses estimated in this study for the entire Ukraine essentially did not change in comparison with a previous estimate, 0.020 vs. 0.021Gy, respectively. The ratio of geometric mean of oblast-specific thyroid doses estimated in the present study to previously calculated doses varied from 0.51 to 3.9. The highest increase in thyroid doses was found in areas remote from the Chornobyl nuclear power plant with a low level of radioactive contamination: by 3.9 times for Zakarpatska Oblast, 3.5 times for Luhansk Oblasts and 2.9 times for Ivano-Frankivsk Oblast. The developed thyroid dosimetry system is being used to revise the thyroid doses due to 131I intake for the individuals of post-Chornobyl radiation epidemiological studies: the Ukrainian-American cohort of individuals exposed during childhood and adolescence, the Ukrainian in utero cohort, and the Chornobyl Tissue Bank.

Assessing the natural and anthropogenic radionuclide activities of the Pechora River estuary: Bottom sediments and water (Arctic Ocean Basin)

This paper studies the activity of natural and technogenic radionuclides in bottom sediments and surface water of the Pechora River estuary, which is the largest Arctic river within the European part of Russia. The relevance of conducting radioecological studies of this region is associated with active oil and gas activities in the Pechora basin and the presence of potential sources of radiation hazard. The average activities of 137Cs, 226Ra, 232Th, and 40K in bottom sediments were 0.16, 18.72, 13.36, and 373.59 Bq·kg-1, respectively. The average activity of 226Ra in the bottom sediments of the Pechora delta was two times higher than in other rivers of the Arctic basin of the European part of Russia, which is associated with oil and gas activities that are carried out in the Pechora basin. This is due to the fact that the decay products of uranium are the main by-products of oil and gas production. The specific activity of technogenic 137Cs in bottom sediments of the Pechora River delta was low and did not exceed 2.2 Bq·kg-1. We did not detect any radioactive 90Sr in bottom sediments. The low 137Cs activity in the bottom sediments of the Pechora delta was associated with both the larger granulometric composition of the sediments in comparison with the estuaries of the Siberian rivers, and with low concentrations of 137Cs in the terrigenous material (soil) entering the river from the catchment area. This was due to the low levels of 137Cs contamination in the soil of the Pechora river basin. We did not find any negative radiation effects of the underground nuclear explosion “Pyrite” carried out in the northern part of the delta, since there were no other technogenic radionuclides. The values of the radionuclides 3H, 137Cs, 226Ra, 232Th and 40K, as well as the total alpha activity in the surface waters of the Pechora River delta, turned out to be below the detection limit. In surface waters, we were able to determine only the total beta activity, which varied over a range from 19.6 to 59.6 Bq·m-3 with an average value of 33.9 Bq·m-3, which was significantly lower than the radiation safety standards. The values of the radiation hazard parameters were below the world average levels and were not significantly hazardous to the health of people living in the area of the Pechora River delta. We concluded that at present, in the Pechora River delta, there are pastures for reindeer with low levels of natural and man-made radioactivity. These conducted studies are the source material in a series of comprehensive studies of the current radioecological state of the tundra territories of the European part of Russia.

Sources of lanthanides in soils and estimation of their hazards

In recent years, an increase in the input of lanthanides (Ln), an important group of heavy metals (HMs), has been observed in the environment throughout the world (in particular soil). Anthropogenic Ln sources are mainly connected to phosphogypsum, Ln-bearing microfertilizer and micronutrients, and mine waste. Therefore, assessment of the hazards associated with the presence of Ln in the soil is an urgent issue. Hazardousness, depending strongly upon the buffer capacity of a specified soil, is determined by the organic matter content, the pH value and other soil properties. For a standard soil (containing 10% organic matter and 25% clay), the discrepancy of the hazardousness of HMs can be estimated based on the maximum permissible concentration (MPC) values proposed by ecologists in the Netherlands. Low levels of Ln contamination in the soil are found, making it possible to classify them in the group of moderately and weakly acting pollutants. The MPC value proposed for cerium (Ce) in the standard soil is 44 mg kg −1 . Approximate MPC values for several other lanthanides (Ln, Pr, Nd, Sm, Gd and Dy) in soils were proposed based on MPC values for freshwater sediments in the Netherlands. According to the MPC value, Ln falls into the group of moderate- and low-hazardous heavy metals.

Current hydroecological state of the Ural River in the lower reaches

Climate and hydrological changes in the Ural River basin, together with water management activities determine the current hydroecological state of the river in its lower course. In comparison with the conventional natural background, the salinity of water in high water period increased by 2.5 times, in low water period- by 5-8 %. Contamination of the lower course of the river is caused by the inflow of pollutants from the upstream sections and the confluence of the polluted tributaries. In the area with no tributaries, the water is characterized as “standard-clean”. The saprobity indices, which characterize the content of organic substances in water, are located within the boundaries of the b-mesosaprobic zone, which characterize low level of water contamination. The content of dissolved oxygen indicates insufficient aeration of the river water during most of the year. The lowest oxygen content is observed during winter period.

Comparative Assessment of the Quality of Aerosol Filters for the Analysis of Ambient Air Pollution

Introduction. Atmospheric aerosols contain many carcinogenic and toxic substances, a significant part of which is represented by heavy metals. Traditionally, metal analysis is preceded by air sampling on AFA-HA-20 filters; yet, the lack of regulations on permitted background levels of trace elements in the filter material may limit reliability of measurements. Selection of filters with similar technological parameters can be a way to improve analytical accuracy. Objective: To determine contamination of different types of filters and to establish its effect on the results of spectral analysis of airborne metal concentrations in a large industrial city. Materials and methods: We analyzed unexposed AFA-HA-20 filters and Merck Millipore MF filters (n = 30 each) for the content of 13 heavy metals identified as priority pollutants within the Federal Clean Air Project. To assess the effect of filter contamination on the analytical error, air sampling was performed by exposing Merck Millipore MF filters at mobile monitoring stations in the city of Lipetsk. The filters were then analyzed by inductively coupled plasma mass spectrometry with prior microwave mineralization. Results: Our findings confirm the repeatedly obtained data on metal contents in null AFA-HA-20 filters and indicate significantly lower levels of contamination of unexposed Millipore MF filters made of mixed cellulose ethers. Conclusions: The risk of obtaining false positive and false negative results depends on the level and variability of the content of a particular trace metal in the filter. The AFA-HA-20 type of filters traditionally used for ambient air sampling may itself confound measurement result.

Retail chicken meats as potential sources of Clostridioides difficile in Al-Jouf, Saudi Arabia

Presence of Clostridioides difficile in stool of food birds and animals is a risk for contamination of their meats to become potential sources of human infection. The main virulence factors of C. difficile are its resistance to antibiotics, production of toxins and spores. As far as I know, this is the first study to evaluate C. difficile prevalence in chicken meats, its toxigenic activities and antibiotics sensitivity patterns in Al-Jouf, Saudi Arabia. Totally, 250 raw chicken meat samples were examined. Standard microbiological and biochemical procedures were used for C. difficile isolation and identification. The suspected colonies were tested by L-proline and C. difficile test kits then confirmed by Vitek 2 compact system. Xpect C. difficile toxin A/B test was used to detect A/B toxins production. Antibiotics susceptibility patterns were detected by Epsilon tests. C. difficile was isolated from 11/250 (4.40%) chicken meat samples; 5/65 (7.69%) legs, 3/65 (4.61%) thighs, 2/60 (3.33%) wings and 1/60 (1.67%) breasts (p = 0.4). All isolates were non-toxigenic. Although all isolates were vancomycin sensitive, some isolates were intermediate/resistant to metronidazole, tetracycline, clindamycin or moxifloxacin antibiotics with variable degrees. C. difficile might contaminate retail chicken meats. Although low level of contamination by non-toxigenic strains was detected, chicken meats should be investigated as C. difficile infection sources for humans especially elders, immune-compromised and long terms wide spectrum antibiotics-used persons. Decreased sensitivity of C. difficile to antibiotics is emerging.

Accumulation of Potentially Toxic Metals in Egyptian Alluvial Soils, Berseem Clover (Trifolium alexandrinum L.), and Groundwater after Long-Term Wastewater Irrigation

The reduced availability of water resources in Egypt has imposed the need to intensify the use of wastewater for crop irrigation in the alluvial soils. Relevant effects can derive from contents of potentially toxic metals (PTMs) in supply resources soils, crops, and groundwater in these areas. For this reason the PTM content has to be monitored to evaluate and minimize health hazards. Therefore, in this context, two areas of the SE Nile Delta subjected to 25 year of wastewater irrigation, using agricultural drainage water (ADW) and mixed wastewater (MWW) were chosen and compared with a nearby site irrigated with Nile freshwater (NFW). At each of the three sites, ten samples of irrigation water, topsoil, berseem clover (Trifolium alexandrinum L.) plants, and seven groundwater samples were collected and analyzed for Cr, Co, Cu, Pb, Ni, and Zn. Results indicate that the total contents of Co, Cu, Ni, and Zn in soils collected from the three sampling sites and Pb in the MWW-irrigated soils were higher than their average natural contents in the earth’s crust, indicating potential risks. The DTPA-extractable contents of Cu in the three sites, in addition to Pb and Zn in the MWW-irrigated soils, exceeded the safe limits. The MWW-irrigated soils showed a considerable degree of metal contamination, while the NFW- and ADW-irrigated soils showed moderate and low levels of contamination, respectively. The contents of the six PTMs in the three sites showed low individual ecological risks, except for Pb in the MWW-irrigated soils that showed a moderate risk; however, the overall ecological risk remained low in all samples. The values of Co, Cu, and Ni in berseem shoot in addition to Pb from the MWW-irrigated soils were over the maximum permissible levels for animal feeding. Values of root-to-shoot translocation factor were lower than 1.0 for Cr, Co and Ni but higher than 1.0 for Cu, Pb, and Zn. Berssem plant is a good candidate for phytofiltration of Cr, Co and Ni, while for extracting Cu, Pb and Zn from polluted soils. The groundwater samples collected from the three sampling sites showed lower metal concentrations than the safe limits for drinking standards. Further remediation studies should be taken into account to alleviate potential environmental and health-related risks when using supply resources different from freshwater.

Exposure radius of a local coal mine in an Arctic coastal system; correlation between PAHs and mercury as a marker for a local mercury source

Mercury in the Arctic originates from emissions and releases at lower latitudes and, to a lesser extent, from local and regional sources. The relationship between mercury (Hg) and polycyclic aromatic hydrocarbons (PAHs) in sediment can be applied as an indicator of the mercury source. This research examines the Hg contamination gradient from a land-based coal mine to the surrounding coastal environment to quantify the impact of local sources. Total mercury and PAH (Σ14PAH) were measured in terrestrial and marine sediments as well as in marine biota. Samples were collected at the mine and two reference sites. Mercury and Σ14PAH concentrations in samples collected at the mine site were significantly higher than those at the reference sites. This was also found in the biota samples, although less pronounced. This work addresses the complexities of interpreting data concerning very low contaminant levels in a relatively pristine environment. A clear correlation between PAH and Hg concentration in sediment was found, although a large number of samples had levels below detection limits. PAH profiles, hierarchical clustering, and molecular diagnostic ratios provided further insight into the origin of PAHs and Hg, showing that signatures in sediments from the nearest reference site were more similar to the mine, which was not the case for the other reference site. The observed exposure radius from the mine was small and diluted from land to water to marine biota. Due to low contamination levels and variable PAH profiles, marine biota was less suitable for tracing the exposure radius for this local land-based Hg source. With an expected increase in mobility and availability of contaminants in the warming Arctic, changes in input of PAHs and Hg from land-based sources to the marine system need close monitoring.Graphical abstract

SAUTE: sequence assembly using target enrichment

BackgroundIllumina is the dominant sequencing technology at this time. Short length, short insert size, some systematic biases, and low-level carryover contamination in Illumina reads continue to make assembly of repeated regions a challenging problem. Some applications also require finding multiple well supported variants for assembled regions.ResultsTo facilitate assembly of repeat regions and to report multiple well supported variants when a user can provide target sequences to assist the assembly, we propose SAUTE and SAUTE_PROT assemblers. Both assemblers use de Bruijn graph on reads. Targets can be transcripts or proteins for RNA-seq reads and transcripts, proteins, or genomic regions for genomic reads. Target sequences are nucleotide and protein sequences for SAUTE and SAUTE_PROT, respectively.ConclusionsFor RNA-seq, comparisons with Trinity, rnaSPAdes, SPAligner, and SPAdes assembly of reads aligned to target proteins by DIAMOND show that SAUTE_PROT finds more coding sequences that translate to benchmark proteins. Using AMRFinderPlus calls, we find SAUTE has higher sensitivity and precision than SPAdes, plasmidSPAdes, SPAligner, and SPAdes assembly of reads aligned to target regions by HISAT2. It also has better sensitivity than SKESA but worse precision.

Environmental Characterization of Underwater Munitions Constituents at a Former Military Training Range.

As a result of military activities, unexploded ordnance and discarded military munitions are present in underwater environments, which has resulted in the release of munitions constituents including the high explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), along with their primary degradation products, to the water column and adjacent sediments. The present study focused on the characterization of underwater exposure and concentrations of energetics such as TNT and RDX at the former Vieques Naval Training Range at Bahia Salina del Sur (Vieques, Puerto Rico, USA), a bay with documented high incidence of munitions. In situ passive sampling using polar organic chemical integrative samplers (POCIS) was used for the detection and quantification of constituents in water at target locations approximately 15 to 30 cm from 15 individual potentially leaking munitions, and also at 15 unbiased locations approximately evenly spaced across the Bay. For comparison with POCIS-derived concentrations, grab samples were taken at the POCIS target locations. The POCIS-derived and averaged grab samples agreed within a factor of 3. When detected, munitions constituent concentrations (primarily TNT and RDX) were observed at ultratrace concentrations (as low as 4 ng/L for RDX), except 30 cm from one General Purpose bomb where the TNT concentration was 5.3 µg/L, indicating that low-level contamination exists at Bahia Salina del Sur on a very localized scale despite the relatively high density of munitions, similar to previously reported results for other munitions sites around the world. Sediment and porewater sampled at 4 stations where munitions constituents were detected in the water column had concentrations below detection (approximately 5 µg/kg and 5 ng/L, respectively), suggesting that the sediment was not a sink for these constituents at those locations. Environ Toxicol Chem 2022;41:275-286. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Contamination, sources and health risk of heavy metals in soil and dust from different functional areas in an industrial city of Panzhihua City, Southwest China

The contamination of heavy metals in urban soil and dust is closely related to anthropogenic emissions, while to what extent the metal contamination varies among different functional areas in industrial cities remains unclear. In this study, the contamination and health risk of seven heavy metals in the soil and dust were assessed at different functional areas of Panzhihua City, Southwest China, and their sources were identified by the spatial divisions and Pb isotopes. The results showed that the contamination of V and Cr in the vanadium/steel plant (VsA) and the contamination of Cd, Pb and Zn in the iron-ore smelting (IsA) were significantly higher relative to other functional areas. The sources of the contaminated heavy metals in the soil and dust were mainly from smelting and manufacturing vanadium/steel products, coal combustion and traffic. Vanadium and Cr were the major metals primarily contributing to the noncarcinogenic and carcinogenic risks, despite the low contamination level of Cr. The results indicate that the VsA is the priority control area in the Panzhihua City, and besides V, more attention should be paid in the future to monitor Cr risk in the soil and dust because of its high contribution to the health risk.

Accumulation of selected metals and concentration of macroelements in liver and kidney tissues of sympatric golden jackal (Canis aureus) and red fox (Vulpes vulpes) in Somogy County, Hungary

This study examined the concentrations of Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn in the liver and kidney samples of golden jackals (n = 163) and red foxes (n = 64). Additionally, we studied how sex affected element concentration in both species, and in the case of golden jackals, how concentration levels were affected by age.Liver was the most important storage organ for Cu, Fe, Mn, and Zn, while kidney for Cd and Na in jackals and foxes.We found no sex-related differences in concentration of any of the selected elements in fox samples. In jackals, the mean concentrations of Al, Mn, and Zn were significantly higher in kidneys of males, while Zn and Cu had higher concentrations in female livers. Our results suggest bioaccumulation processes do not occur in mesocarnivores.Lead and Cd concentrations fell within ranges accepted as normal for canine species and were below toxic levels in the organs of the examined species. Concentrations of Cr, Cu, Fe, Mn, and Zn were far below the toxic levels in both organs of both species, with a slight sign of deficiency of Fe, Mn, and Zn in jackal and fox kidneys. In comparison with toxicity levels and results from other European study sites, the current study demonstrated that species living in the examined area of Somogy County, Hungary, are generally exposed to low levels of environmental contamination.

Evidence of low levels of trace organic contaminants in terminal lakes

Endorheic lakes (or terminal lakes, TLs) have no natural outlet other than evaporation and slow infiltration. Some TLs receive reclaimed wastewater which contains poorly removed trace organic contaminants (TrOCs). To determine if TLs accumulate TrOCs we conducted a preliminary assessment of the occurrence of ten TrOCs in three TLs receiving reclaimed wastewater and one TL which does not directly receive reclaimed wastewater. Five of ten TrOCs (carbamazepine, DEET, fluoxetine, primidone, and trimethoprim) were present in all four TLs’ surface waters (~0.3–1109 ng/L), six (caffeine, carbamazepine, DEET, diphenhydramine, primidone, and trimethoprim) were present in sediment samples (0.1–77 ng/gDW) and in soil samples (0.1–137 ng/gDW). Concentrations of caffeine, carbamazepine, diphenhydramine, fluoxetine and meprobamate were significantly higher in TLs receiving wastewater from a secondary treatment plant compared to those TLs which received tertiary treated wastewater. Carbamazepine, fluoxetine, sulfamethoxazole, and trimethoprim were present at concentrations greater than is typical of other U.S. freshwater lakes, but other TrOC concentrations were present at lower concentrations than in other freshwater lakes. We conclude that some TrOCs may accumulate in TLs, but to a lesser extent than would be expected based on the accumulation of dissolved constituents alone, which indicates that there are other unidentified processes in TLs that contribute to TrOC losses. Other TLs across the globe may have similar levels of TrOCs due to anthropogenic influence and treated wastewater inputs.

Stratified sampling in highly polluted data as an effective and reliable alternative to high breakdown point estimators

Observations on certain real-life cases include units that are incompatible with other data sets. Values that are extreme in nature do influence estimates obtained by conventional estimators. Robust estimators are therefore necessary for efficient estimation of parameters. This paper uses stratification with simple random sampling without replacement to optimize sample allocation in stratum for efficient parameter estimation as an alternative method of handling highly contaminated samples. Our proposed method stratifies the highly contaminated population into two non-overlapping sub-populations, and stratified samples of sizes 50, 200, and 500 was drawn. We estimate the model parameters form the contaminated sampled data using ordinary least squares under the proposed method, and using the two high breakdown point estimators; the Least Median of Squares and Least Trimmed Squares. Our findings shows that the proposed method did not perform well for low contamination levels (⩽ 30%) but outperformed Least Median of Squares and Least Trimmed Squares for higher contamination rates (⩾ 40%). This indicates that our proposed method compares well and compete favorably with the two high breakdown point estimators.

An Alternative Solvent Extraction Flowsheet for Separating 237Np from 238Pu for Space Power Applications

ABSTRACT The production of 238Pu from 237Np, to the specifications required for space flight, requires the separation of plutonium from neptunium and a range of fission products. The valuable neptunium is then recycled into targets for further irradiation. At Oak Ridge National Laboratory (ORNL), a solvent extraction process has been developed to separate neptunium and plutonium that uses sodium nitrite to control the neptunium oxidation. This results in a neptunium product contaminated with sodium, which needs to be removed prior to recycling. We have developed a separation process that results in a sodium-free neptunium product with very low levels of plutonium contamination, there by reducing the number of purification steps and thus simplifying the process.

Shellfish contamination with lipophilic toxins and dietary exposure assessments from consumption of shellfish products in Shenzhen, China

Lipophilic shellfish toxins (LSTs) can cause human illness and therefore represent a serious threat to public health. Shellfish are the main dietary source of LSTs, but very few studies have appraised dietary exposure to LSTs through shellfish consumption in China. We measured levels of multiple LSTs in shellfish samples sold in the principal wholesale seafood market in the southern coastal city of Shenzhen, and we estimated the potential for acute and chronic LST exposure of the Shenzhen population via ingestion of shellfish. LST contamination data were obtained from a total of 14 species of 188 commercial samples. Eleven individual LSTs, namely okadaic acid (OA), dinophysis toxin-1 and −2 (DTX1 and DTX2), pectenotoxin-2 (PTX2), yessotoxin and homo yessotoxin (YTX and hYTX), azaspiracid-1, −2 and −3 (AZA1, AZA2, AZA3), spirolides (SPXs), and gymnodimine (GYM), were determined using liquid chromatography electrospray-ionization tandem mass spectrometry (LC-ESI-MS/MS). More than two thirds of samples showed undetectable LSTs, while the detection rates (the proportion of samples with detectable LSTs) of individual LSTs ranged from 0% to 45.7%. Most shellfish samples had lower levels of LST contamination than the corresponding limits of detection (LODs), while some samples had levels of hYTX and GYM that exceeded the limits of quantification (LOQs). Overall, levels of LSTs in the 188 samples were below the regulatory limits set by most countries. Acute and chronic exposures of LST were estimated by a point-estimate modeling method that combined sample contamination data with consumption data from dietary survey of Shenzhen residents and consumption figures proposed by EFSA, the European Food Safety Authority. Seasonal variations in LST concentrations were noted in some instances. Overall, the estimated acute exposure to LSTs based on consumption of large-size shellfish portions and the maximum LSTs contamination level were below the provisional acute reference doses (ARfDs) proposed by the EFSA. Chronic exposure estimates based on mean and 99th percentile consumption of shellfish by Shenzhen residents and mean LSTs contamination levels in the collected samples were from 2452 to 74 times lower than those associated with estimated acute exposure levels.

Heavy metal content in pumpkin pond of Kutaraja Fishing Port Banda Aceh

Fishing port scan support fishery resources management by incorporating social-economic activities to improve the local community's welfare; however, it can also negatively impact the environment by increasing waste pollution to the surrounding waters. Kutaraja Fishing Port, Banda Aceh, is one of the active fishing ports that conduct multiple activities, such as industrials, transportations, and domestic activities threatening the environment through the production of pollution such as heavy metals. The purpose of this study is to determine the concentration of heavy metals Zinc (Zn) and Chromium (Cr) and the sediment contamination level in the Kutaraja Fishing Port, Banda Aceh. This research was conducted in February 2021 at the water site of Samudra Kutaraja Fishing Port, Banda Aceh, and sampled sediments using the purposive sampling method. Samples were then analyzed for heavy metal concentration using the Atomic Absorption Spectrophotometer (AAS) instrument in the laboratory of the Aceh Industrial Research and Standardization Center (BARISTAND). The results showed that the concentration of heavy metal Zn ranged from 15.6507 - 27.2939 mg/kg. The majority of heavy metal Cr concentrations were below the test limit of 0.000, except at station 2, which was 9.1212. Both heavy metal concentrations are still categorized as low contamination criteria and still below the Australian and New Zealand Environment and Conservation Council (ANZECC, 2000) and the Canadian Council of Ministers for the Environment (CCME, 2002). This research proved that both heavy metals do not threaten the biota and have a low contamination level in the waters.Keywords:SedimentHeavy metal (Zn)Heavy metal (Cr)Atomic-absorptionSpectro-photometerAssessment

Occurrence and risk assessment of pharmaceuticals and personal care products (PPCPs) against COVID-19 in lakes and WWTP-river-estuary system in Wuhan, China

The consumption of pharmaceuticals and personal care products (PPCPs) for controlling and preventing the COVID-19 would have sharply increased during the pandemic. To evaluate their post-pandemic environmental impacts, five categories of drugs were detected in lakes and WWTP-river-estuary system near hospitals of Jinyintan, Huoshenshan and Leishenshan in the three regions (J, H and L) (Regions J, H and L) in Wuhan, China. The total amount of PPCPs (ranging from 2.61 to 1122 ng/L in water and 0.11 to 164 ng/g dry weight in sediments) were comparable to historical reports in Yangtze River basin, whereas the detection frequency and concentrations of ribavirin and azithromycin were higher than those of historical studies. The distribution of concerned drugs varied with space, season, media and water types: sampling sites located at WWTPs-river-estuary system around two hospitals (Regions L and J) usually had relatively high waterborne contamination levels, most of which declined in autumn; lakes had relatively low waterborne contamination levels in summer but increased in autumn. The potential risks of detected PPCPs were further evaluated using the multiple-level ecological risk assessment (MLERA): sulfamethoxazole and azithromycin were found to pose potential risks to aquatic organisms according to a semi-probabilistic approach and classified as priority pollutants based on an optimized risk assessment. In general, the COVID-19 pandemic did not cause serious pollution in lakes and WWTPs-river-estuary system in Wuhan City. However, the increased occurrence of certain drugs and their potential ecological risks need further attention. A strict source control policy and an advanced monitoring and risk warning system for emergency response and long-term risk control of PPCPs is urgent.

The State of Microbiological Cleanliness of Surfaces and Equipment of an Endoscopic Examination Laboratory-Data from a Reference Tertiary Clinical Endoscopy Center in Southern Poland.

The increasing number of endoscopic procedures performed and their increasing invasiveness mean that endoscopy of the gastrointestinal tract is associated with the risk of transmitting pathogenic microorganisms through infected equipment or contact with other patients and medical staff. In order to ensure protection of the health of both patients and medical staff, endoscopy laboratories should meet high hygiene standards. The results of tests of the microbiological cleanliness of surfaces and equipment of an endoscopic examination laboratory performed in the period from January to December 2019 at the Provincial Clinical Hospital No. 2 in Rzeszow were assessed retrospectively. Samples for testing were collected by swabbing from places where microbiological contamination was the most likely and cleaning was the most difficult. In the analyzed period, a total of 86 samples were collected for microbiological tests, of which positive results accounted for 6.9%. Positive results were obtained mainly from swabs collected from wet surfaces (66.7%). Most of the isolated microorganisms were Gram-negative bacteria (66.7% of all positive tests) and they were: Acinetobacter junii, Ralstonia pickettii, and Achromobacter denitrificans. The condition of the microbiological cleanliness of the surfaces and equipment of the endoscopic examination laboratory was satisfactory. A very low level of microbiological contamination of the tested items indicates occasional shortcomings in the decontamination processes. Since microorganisms isolated from the collected samples may be the cause of infection in patients and medical personnel, it is necessary to verify the decontamination procedures applied and to continue periodic microbiological monitoring of their effectiveness.

The Use of Ribosomal RNA as a Microbial Source Tracking Target Highlights the Assay Host-Specificity Requirement in Water Quality Assessments.

For microbial source tracking (MST), the 16S ribosomal RNA genes (rDNA) of host-specific bacteria and mitochondrial DNA (mtDNA) of animal species, known to cause fecal contamination of water, have been commonly used as molecular targets. However, low levels of contamination might remain undetected by using these DNA-based qPCR assays. The high copy numbers of ribosomal RNA (rRNA) could offer a solution for such applications of MST. This study compared the performance of eight MST assays: GenBac3 (general Bacteroidales), HF183 (human), BacCan (dog), Rum-2-Bac (ruminant), Pig-2-Bac (swine), Gull4 (gull), GFD, and Av4143 (birds) between rRNA-based and rDNA-based approaches. Three mtDNA-based approaches were tested: DogND5, SheepCytB, and HorseCytB. A total of 151 animal fecal samples and eight municipal sewage samples from four regions of Finland were collected for the marker evaluation. The usability of these markers was tested by using a total of 95 surface water samples with an unknown pollution load. Overall, the performance (specificity, sensitivity, and accuracy) of mtDNA-based assays was excellent (95–100%), but these markers were very seldom detected from the tested surface water samples. The rRNA template increased the sensitivity of assays in comparison to the rDNA template. All rRNA-based assays (except Av4143) had more than 80% sensitivity. In contrast, only half (HF183, Rum-2-Bac, Pig-2-Bac, and Gull4) of rDNA-based assays reached this value. For markers targeted to bird feces, the use of the rRNA-based assay increased or at least did not change the performance. Regarding specificity, all the assays had >95% specificity with a DNA template, except the BacCan assay (71%). While using the RNA template for the assays, HF183 and BacCan exhibited only a low level of specificity (54 and 55%, respectively). Further, the HF183 assay amplified from multiple non-targeted animal fecal samples with the RNA template and the marker showed cross-amplification with the DNA template as well. This study recommends using the rRNA-based approach for MST assays targeting bird fecal contamination. In the case of mammal-specific MST assays, the use of the rRNA template increases the sensitivity but may reduce the specificity and accuracy of the assay. The finding of increased sensitivity calls for a further need to develop better rRNA-based approaches to reach the required assay performance.