Contaminant Loads Research Articles

Some metals and metalloids in the blood of three species of shorebirds increase while foraging during two-week migratory stopover in Delaware Bay, New Jersey

Most migratory shorebird species are declining, some are endangered, and some may be vulnerable to contaminants on long distance travel between wintering grounds and high latitude breeding grounds. We examined whether shorebirds accumulated trace elements at the Delaware Bay (New Jersey) stopover by testing the null hypothesis that there was no difference in the levels of arsenic, cadmium, chromium, lead, mercury, and selenium in blood of three species of shorebirds collected early in their stopover compared to levels in blood collected about two weeks later near the end of the stopover, before departing for breeding grounds. There were significantly higher levels of all metals and metalloids in the blood of ruddy turnstone (Arenaria interpres) later in May than earlier. There were seasonal increases in blood levels of arsenic and selenium for all three species. Chromium and lead levels also increased in red knots (Calidris canutus). These increases occurred although the birds were only present for about two weeks. Levels of arsenic, mercury, and lead in knots and selenium in sanderlings (Calidrris alba), exceeded reported effects levels. These results have potential implications for studying the refueling physiology, energetics, and feeding behavior of migratory shorebirds. However, they also suggest cause for concern because the increased contaminant loads occur in a short period, and the high metal level bolus received all in a few days may result in adverse effects.

Implications on freshwater lake-river ecosystem protection suggested by organic micropollutant (OMP) priority list

Lake-river complex systems represent interconnected ecosystems wherein inflow rivers significantly influence the migration of terrigenous contaminants, particularly organic micropollutants (OMPs), into lakes. Given the extensive array of OMPs, screening for those with the highest potential hazard is crucial for safeguarding freshwater lake-river ecosystems. In this study, an optimized multi-criteria scoring method was applied to prioritize OMPs. Flux estimation was then performed to identify the contamination load contributed by the Le’an River to Poyang Lake. Higher concentrations of phthalate esters (PAEs) were detected in the lake-river system, ranging from 1154.5 to 22,732.8 ng/L, followed by antibiotics and polycyclic aromatic hydrocarbons (PAHs), while historical pollutant residues were comparably lower. Based on the prioritization methodology, 27 compounds, encompassing eight PAEs, six organochlorine pesticides (OCPs), six polychlorinated biphenyls (PCBs), five PAHs and two antibiotics, emerged as priority pollutants. Multiple risk assessments revealed that priority PAEs posed relatively high ecological and human health risks; concurrently, the annual fluxes of individual priority PAEs into the lake all exceeded 1000 kg, with DBP, DEHP and BBP fluxes reaching 18,352, 10,429, and 7825 kg, respectively. This research offers valuable insights stemming from OMP prioritization to aid in the conservation of freshwater lake ecosystems, particularly concerning lake-river system integrity.

Groundwater uranium contamination from produced water disposal to unlined ponds in the San Joaquin Valley

In the southern San Joaquin Valley (SJV) of California, an agriculturally productive region that relies on groundwater for irrigation and domestic water supply, the infiltration of produced water from oil reservoirs is known to impact groundwater due to percolation from unlined disposal ponds. However, previously documented impacts almost exclusively focus on salinity, while contaminant loadings commonly associated with produced water (e.g., radionuclides) are poorly constrained. For example, the infiltration of bicarbonate-rich produced waters can react with sediment-bound uranium (U), leading to U mobilization and subsequent transport to nearby groundwater. Specifically, produced water infiltration poses a particular concern for SJV groundwater, as valley-fill sediments are well documented to be enriched in geogenic, reduced U. Here, we analyzed monitoring well data from two SJV produced water pond facilities to characterize U mobilization and subsequent groundwater contamination. Groundwater wells installed within 2 km of the facilities contained produced water and elevated levels of uranium. There are >400 produced water disposal pond facilities in the southern SJV. If our observations occur at even a fraction of these facilities, there is the potential for widespread U contamination in the groundwaters of one of the most productive agricultural regions in the world.

Landscape Pollution Source Dynamics Highlight Priority Locations for Basin‐Scale Interventions to Protect Water Quality Under Hydroclimatic Variability

AbstractExtreme weather is associated with a variety of water quality issues that can pose harm to humans and aquatic ecosystems. Under dry conditions, contaminants become concentrated in streams with a greater potential for harmful algal blooms, while wet conditions can cause flooding and broadcast pollution. Developing interventions to improve water quality in a changing climate requires a better understanding of how hydroclimatic variability affects watershed processes, and which places are most vulnerable. We developed a Soil and Water Assessment Tool model of the Cape Fear River Basin (CFRB) in North Carolina, USA, representing contemporary land use, point and non‐point sources, and weather conditions from 1979 to 2019. The CFRB is a large, complex river basin undergoing urbanization and agricultural intensification, with a history of droughts and floods. To identify intervention priorities, we developed a Water Quality Risk Index (WQRI) using the average and variability of contaminant loads across dry, normal and wet conditions. The landscape generally contributed the majority of pollutants (e.g., via erosion, fertilizer and manure applications), including 90.1% of sediment, 83.2% of total nitrogen, and 52.4% of total phosphorus at the City of Wilmington's drinking water intake, yet point sources were influential during dry periods. Approximately 16% of the watershed contributed most of the pollutants across conditions—these represent priority locations for interventions such as restoration, urban, or agricultural best management practices. The WQRI approach considering risks to water quality across conditions can help identify locations where interventions are more likely to improve water quality under climate change.

Groundwater Vulnerability to Nitrate Contamination from Fertilizers Using Modified DRASTIC Frameworks

Vulnerability maps of groundwater provide an efficient means of identifying environmental trends and prioritizing regions for prevention plans. The GIS-based DRASTIC method, however, does not consider the impact of contamination, so there is a need to modify it according to the specifics of the region and its contamination load. The aim of this study is to investigate a suitable DRASTIC modification for vulnerability assessment by changes in its rating and weighting systems. The goal is to explore and compare the impact of both objective and subjective weighting methods in the vulnerability assessment of a smaller aquifer situated beneath agricultural land. The frequency ratio (FR) method is used to adjust the DRASTIC index rates based on nitrate contamination as the main contamination from fertilizers extensively used in the study area. The DRASTIC parameters’ weights are determined using two objective and subjective methods, including Shannon entropy and single-parameter sensitivity analysis (SPSA), respectively. In total, five frameworks, including FR-DRASTIC, DRASTIC-Entropy, DRASTIC-SPSA, FR-SPSA, and FR-Entropy are developed and evaluated. We validate these proposed vulnerability indices based on the nitrate concentrations in 14 samples. The results show that the vulnerability map obtained from the FR-Entropy framework is superior, showing a 0.85 correlation with nitrate concentrations. Notably, Shannon entropy as an objective weighting method outperformed the subjective SPSA approach.

Dynamics of particles and phosphorus in canals of the Lower Everglades, Florida, USA

Water flow (discharge) can affect water quality by influencing the concentration and transport of waterborne contaminants. The effects of discharge on phosphorus (P) and particle concentrations in managed canals, were described using concentration-discharge (C–Q) relationships, accumulation of suspended and settling particles, and the physicochemical characteristics of these particles and bed sediments. Piecewise regression analysis on C–Q relationships revealed slope inflections that denoted thresholds, where P-behavior changed from low to high discharge. The C–Q relationships generally showed higher concentrations at higher discharges. In three of the four Lower Everglades canals studied, long-term (1995–2019) lower temporal resolution data (daily to weekly) was adequate to describe the influence of discharge on P concentrations. However, in one site, the L–29 Canal, higher temporal resolution data (minutes to hours over weeks), derived from acoustic sensors, was necessary to produce C–Q relationships. In the L–29 Canal, discharge affected the transport, settling, and sediment accrual at distances from the S333 inflow structure. Sediment traps showed higher discharge led to a greater accumulation of suspended particles that were transported and settled farther downstream. Generally, downstream surface sediments in the L–29 Canal had greater organic matter, lower bulk density and higher TP than those of the upstream site, reflecting long-term effects of discharge. Understanding the effects of discharge on particles and associated nutrients, especially at discharge thresholds that lead to concentration increases, can inform the operation of managed canals to reduce contaminant loading to downstream sensitive ecosystems.

Five Years Measuring the Muck: Evaluating Interannual Variability of Nutrient Loads From Tidal Flooding

Due to sea level rise, tidal flooding is now common in low-lying coastal systems around the world. Yet, the contribution of tidal flooding to non-point source nutrient loads and their impact on the quality of adjacent waters remains poorly constrained. Here, we quantified dissolved nutrient loading and Enterococcus abundance during annual autumnal king tides (i.e., perigean spring tides), between 2017 and 2021, in a sub-watershed of the lower Chesapeake Bay. To calculate nutrient loading from tidal flooding, we used geospatial inundation depths from a street-level hydrodynamic model to estimate floodwater volumes during each of the five sampling events and the difference between nutrient concentrations in floodwater and pre-flood measurements. Results showed that dissolved nutrient concentrations were higher in floodwaters than in estuarine waters and resulted in dissolved nitrogen and phosphorus loads that reached 58.4 × 103 kg and 14.4 × 103 kg, respectively. We compared our load estimates to the tributary-specific total and land-based federal allocations (i.e., total maximum daily loads (TMDL)) for total nitrogen (TN) and total phosphorus (TP). Even the more conservative calculations indicate that inputs of dissolved nutrients during a single tidal flooding event can exceed 100% of the annual load allocation. Additionally, more than 80% of the floodwater samples collected each year showed Enterococcus abundance that exceeded the threshold for recreational water use in Virginia (104 MPN 100 ml−1). Failing to account for non-point source loading of nutrients and contaminants from tidal flooding as sea level rises could result in worsening eutrophication and deterioration of coastal economies and the health of coastal communities around the world.

Photo-electrochemical oxidation flow system for stormwater herbicides removal: Operational conditions and energy consumption analysis

Photoelectrochemical oxidation (PECO) is a promising advanced technology for treating micropollutants in stormwater. However, it is important to understand its operation prior to practical validation. In this study, we introduced a flow PECO system designed to evaluate its potential for full-scale applications in herbicides degradation, providing valuable insights for future large-scale implementations. The PECO flow reactor demonstrated the ability to treat a larger volume of stormwater (675 mL, approximately 10 times more than previous batch experiments) with effective removal rates of 92 % for diuron and 22 % for atrazine over 6 h of operation at 2 V. To address the large volume issue in stormwater treatment, a multiple module parallel application design is being considered to increase the treatment capacity of the PECO flow reactor. During the flow reactor operations, flow rate was found to have a notable impact on removal performance, particularly for diuron. At a flow rate of 610 mL min−1, approximately 90 % removal of diuron was achieved, while at 29 mL min−1, the removal efficiency decreased to 60 %. While light intensity had minimal effect on diuron degradation (all settings achieved over 90 % removal), it enhanced atrazine degradation from 9 % to 31 % with an increase in intensity from 63 mW cm−2 to 144 mW cm−2. Remarkably, the PECO flow system exhibited excellent removal performance (>90 % removal) for diuron even at extremely high initial pollutant concentrations (240 μg L−1), demonstrating its capacity to handle varying contaminant loads in stormwater. Energy consumption analysis revealed that flow rate as the primary factor influenced the specific energy consumption rate. Higher flow rate (e.g., 610 mL min−1) were preferable in flow reactor due to its well-balanced performance between removal and energy consumption. These findings confirm that the PECO flow system offers an efficient and promising approach for stormwater treatment applications.

Efficacy of an off-line constructed wetland for mitigating nitrogen loss from a pastoral catchment

ABSTRACT Constructed wetlands are an established mitigation option for reducing contaminant loads from pastoral land in New Zealand. We assess the long-term performance of a 0.5 ha, off-line, horizontal surface flow wetland, installed on a dairy farm with the primary objective of nitrate removal. Over seven years the median removal rates for nitrate-nitrogen (NO3–N), total nitrogen and total suspended solids were 45%, 33% and 74%, respectively. Whilst dissolved reactive phosphorus (DRP) was initially removed, over time the wetland progressed to a small exporter of DRP. Median NO3–N mass removal was 417 kg yr−1 , which is considerable for such a small wetland, and equivalent to 7% of total modelled ‘farm-scale’ losses. Nitrate removal was found to be seasonal and although it could be simulated using a conventional wetland model with Arrhenius temperature dependence, the resulting joint estimates of k 20 and Θ were uncertain. We estimate the NO3–N removal cost-effectiveness of the wetland (over a 25-year lifespan) to be NZ$34 kg N−1. We foresee opportunities for off-line constructed treatment wetlands to be an effective nitrate mitigation option in perennial drains and lowland streams in pastoral catchments, but also emphasise the need for on-going maintenance to ensure longevity of performance.

Impacts of climate change on nutrient and sediment loads from a subtropical catchment

Climate change is predicted to significantly alter hydrological cycles across the world, affecting runoff, streamflow, and pollutant loads from diffuse sources. The objectives of this study were to examine the impacts of climate change on streamflow, total nitrogen (TN), total phosphorus (TP), and total suspended sediment (TSS) loads in the subtropical Logan-Albert catchment, Queensland, Australia. We calibrated the Soil Water Assessment Tool (SWAT) against event monitoring data in the Logan and Albert rivers, respectively. Hydrological and water quality effects of an ensemble of 11 dynamically downscaled high-resolution climate models were assessed with SWAT under high (Representative Concentration Pathway 8.5 – RCP8.5) and intermediate (RCP4.5) emission scenarios. Streamflow decreased most in winter and spring and decreased least in summer. This followed the predicted seasonal changes for precipitation, although decreases tended to be amplified due to increasing evaporative loss. TSS, TN, and TP loads showed a similar pattern to streamflow, with the largest decreases predicted for the dry season under RCP8.5 by the 2080s. Annual TSS load decreased by 34.3 and 54.2%, TN load decreased by 29.8 and 30.5%, and TP load by 24.9 and 4.4% for the Logan and Albert sites, respectively. The results of this study indicate that for subtropical river-estuary systems, climate warming may lead to lower streamflow and contaminant loads, reduced flushing, and greater relative importance of point source loads in urbanising catchments.

An integrative perspective on fish health: Environmental and anthropogenic pathways affecting fish stress

Multifactorial studies assessing the cumulative effects of natural and anthropogenic stressors on individual stress response are crucial to understand how organisms and populations cope with environmental change. We tested direct and indirect causal pathways through which environmental stressors affect the stress response of wild gilthead seabream in Mediterranean costal lagoons using an integrative PLS-PM approach. We integrated information on 10 environmental variables and 36 physiological variables into seven latent variables reflecting lagoons features and fish health. These variables concerned fish lipid reserves, somatic structure, inorganic contaminant loads, and individual trophic and stress response levels. This modelling approach allowed explaining 30 % of the variance within these 46 variables considered. More importantly, 54 % of fish stress response was explained by the dependent lagoon features, fish age, fish diet, fish reserve, fish structure and fish contaminant load latent variables included in our model. This integrative study sheds light on how individuals deal with contrasting environments and multiple ecological pressures.

Physicochemical and microbial assessment of effluent from slaughter slab in Kirtipur Municipality, Kathmandu, Nepal

The number of slaughterhouse facilities and retail meat shops has been on the rise, leading to an increase in the amount of wastewater they produce. Wastewater is hazardous to the environment as it causes deoxygenation in water bodies, pollutes the groundwater, and spreads several diseases if released untreated. The study was conducted in slaughter slabs and retail meat shops in Kirtipur Municipality to evaluate the physicochemical characteristics and microbial status of wastewater. Fifteen wastewater samples were collected and analyzed as per APHA-AWWA-WEF for physicochemical and total coliform count. The average values of chemical oxygen demand (COD) and biological oxygen demand (BOD) were 574.5 mg/L and 284.5 mg/L, respectively and exceeded generic standards for tolerance limits for industrial effluent. The average level of total coliform count in the fresh water and wastewater were 733 CFU/100 mL and 7.72 × 104 CFU/100 mL, respectively. There is a significant difference in the total coliform count in freshwater (p value (T > t) = 0.01 < 0.05) and wastewater (p value (T>t) = 0.00 < 0.05). Slaughtering of animals without adhering to hygienic rules leads to a higher load of organic pollutants and other chemical contaminants in wastewater and has detrimental health effects on human, animal, and the environment. The slaughter slabs in Kirtipur Municipality need to be inspected during the process of slaughtering.

Elastan-Polyurethane Treatment for the Stability Improvement of Coal-Fouled Ballast

This study assesses the performance of coal-fouled ballast upon treatment with a hydrophobic elastomeric polyurethane, Elastan [Elastan-stabilized fouled ballast (ESFB)] and compares it with ballast that was initially clean but became fouled after its treatment during the track service life [fouled Elastan-stabilized ballast (FESB)]. The cyclic test results revealed that the performance of ESFB was significantly poorer compared with FESB for similar levels of fouling. The ESFB had undergone higher extent of deformations and had exhibited lower damping and resilient modulus values when compared with FESB. However, the extent of breakage of ballast particles was almost similar in both ESFB and FESB samples. Further, the extent of shear strains developed in ESFB samples, especially at higher void contamination index (VCI) values and loading frequencies, exceeded the shear strain at which breakage of bonds occurred under direct shear loading conditions. Accordingly, the critical loading frequency and fouling content up to which the polyurethane-based treatment is effective is proposed in the current study. In addition, the deformations of both stabilized and unstabilized ballast are seen to be directly influenced by the interface shear strength of ballast.

Detrimental influence of industrial effluents, especially heavy metals, on limnological parameters of water and nutritional profile in addition to enzymatic activities of fish, Sperata seenghala (Sykes, 1839) from diverse Ramsar sites, India (Punjab).

The present research was designed to determine the nutritive value of the liver and intestine of fish, Sperata seenghala, the impact of effluence load on limnological parameters of water and proximate composition of fish organs, especially on fatty acids, liver enzymatic activities, seasonal variations in the nutritional profile of fish, and to check and compare the pollution status of Ramsar sites in Punjab by calculating the water quality index, heavy metal pollution index, and metal index from June 2018 to August 2020. WQI of Harike wetland was found to be 53.95, which depicts that water quality in this region is "poor". At Nangal wetland, water quality index was reported to be "excellent" quality water and fit for the whole ecological unit. Overall heavy metal pollution index for Harike wetland was reported 174.569, whereas for Nangal wetland it was 5.994, depicting massive contaminant loads in a polluted region. MI value was also recorded as being higher (6.9336) in polluted habitat than in control habitat (0.8175). In fish liver, significant (p < 0.05) higher mean total lipids (6.73%), total proteins (3.98%), moisture (77.69%), ash (3.56%), and carbohydrates (3.79%) were observed in the samples from Nangal wetland than Harike wetland. A similar trend was reported in all biochemical contents of the fish intestine. Enzyme activities such as aspartate-aminotransferase and alanine-aminotransferase were significantly elevated (p < 0.05) in the specimens collected from the polluted region. The mean total n-3 (except in spring), n-6 polyunsaturated fatty acids (except in winter), and average monounsaturated and saturated fatty acids diminished significantly (p < 0.05) in the liver of fish from contaminated habitat than control site. In the intestine of fish collected from the polluted region, significant reductions in the mean total n-3 (except in autumn as well as summer), total n-6 PUFAs (in autumn and winter), and total SFAs were reported than control site.

Seasonal variation, contamination and ecological risk assessment of heavy metals in sediments of coastal wetlands along the Bay of Bengal

Functioning of coastal wetland habitats is essential for the ecosystem integrity and sustainability of coastal development that enables human progress along transitional waterways. However, these habitats are continuously being affected by a variety of pollutants including metallic elements. In this study, seasonal variation, pollution status and ecological risks of heavy metals (Cr, Mn, Co, Ni, As, Cu, Zn and Pb) in surface sediment of the several types of coastal wetlands (estuaries, mudflats, sandy beaches, mangroves, and saltmarshes) were detected by using X-ray fluorescence (EDXRF) spectrometry. The results showed that the mean concentration level of metals in the surficial sediment samples followed the order of Cu (84.06 ± 8.60 μg/g) > Zn (51.00 ± 8.97 μg/g) > Mn (38.25 ± 11.34 μg/g) > Cr (3.52 ± 0.91 μg/g) > Pb (0.27 ± 0.13 μg/g) > Co (0.24 ± 0.13 μg/g) > As (0.21 ± 0.12 μg/g) > Ni (0.16 ± 0.08 μg/g). In comparison to the pre-monsoon period, the post-monsoon season had higher concentrations of heavy metals while the overall accumulation level of metals in the wetlands exhibited a pattern of estuarine wetland (28.47 ± 31.35 μg/g) > mangrove (22.23 ± 30.79 μg/g) > mudflat (21.79 ± 29.71 μg/g) > sandy beach (21.47 ± 28.15 μg/g) > saltmarsh (21.28 ± 30.02 μg/g). Although, the pollution assessment indices e.g., contamination factor (CF), degree of contamination (CD), geoaccumulation index (Igeo) and pollution load index (PLI) showed minimal levels of contamination in the studied sites, enrichment factor (EF) suggested greater enrichment of the metals in the pre-monsoon season but with the lowest ecological risk (RI < 40) in both seasons. Cluster analysis, principal component analysis (PCA), and Pearson's correlation were performed to determine the sources of heavy metals in collected samples which specified that Pb, As, Co and Ni predominantly came from natural sources whereas Cu, Mn, Zn and Cr emerged from anthropogenic sources such as industrial effluents, domestic wastewater, fertilizer or pesticide consumption on farmland along the riverbank, vessel emissions, and the confluence of tributary rivers.

Photoluminescence Investigations and Band Gap Engineering in Environment Friendly ZnO Nanorods: Enhanced Water Treatment Application and Defect Model.

The inadvertent discharge of industrial effluents, mainly textile, contributes to the complex contamination load in water bodies. Textile dyes are the critical effluents and recalcitrant to traditional remediation procedures. Therefore, energy viable and environment friendly solutions are needed. In this study, we have synthesized zinc oxide nanorods (NRs) at various temperatures using modified thermal decomposition and evaluated its photocatalytic activities. Field effect scanning electron microscopy has confirmed rod-like morphology till TS = 500 °C and spherical morphology from TS = 600 °C onward. Photoluminescence spectra have shown a prominent defect peak in the synthesized ZnO, except for the NRs synthesized at 300 °C. Synthesized ZnO NRs and NPs have been employed to degrade crystal violet (CV) and congo red (CR) dyes. ZnO NRs have shown impressive photocatalytic performance with faster treatment time as compared to the earlier reports. Synthesis parameters are well correlated with the observed high efficiency and the band gap tailoring. Based on our findings, for the first time, we have proposed (i) defect model correlating synthesis parameters with defect states, (ii) systematic correlation of defect states with photocatalytic efficiency, and (iii) ZnO nanorods synthesized at 300 °C via an improved synthesis method as a promising photocatalytic solution to degrade the CV and CR dyes in contaminated water.

Assessing the Human Health Risk from Heavy MetalContaminated Vegetables Grown Close to the Tannery Industrial Area Using the Hazard Index (HI) and Hazard Quotient (HQ)

To assess the contamination load in vegetables and its possible human health hazards, heavy metals concentration (Cr, Cd, Cu, Pb, Ni, and Zn) in vegetables grown in the vicinity of the studied tannery area were determined. Health risk due to the consumption of vegetables was calculated from the metal concentration of the studied vegetables and the study signifies more potential to cause health hazard (cancer) (Hazard Index&gt;1). The present study indicated that concentrations of Cr in the vegetable species were within the range of 7.5-9.75, 5.38-10.14, 25.5-28.5 and 2.65 mg kg-1 of dry weight (DW), in bottle gourd fruit, bottle gourd shoot, kalmi shoot, and red amaranth, which was above the MPL (1-2 mg/kg). The findings revealed that the mean concentration of the studied heavy metals (Cr, Cd, Pb, Ni, Cu, Zn,) exceeded the MPL in most of the measured vegetables because of higher translocation from the source to edible parts. For the majority of the samples, the ADI values of Cr and Pb were higher than the PMTDI. Open dumping of tannery wastes and effluents, and tanning activities involve serious environmental hazards. Adequate preventive measures should be taken in tannery industrial activities with a view to ensuring a safe, sound, and healthy environment for the greater benefit of Bangladesh.

Metal Contaminants in Fish: Blood as a Potential Non-lethal Monitoring Tool.

The use of fish to monitor metal contamination is well established, but existing studies often focus on internal tissues that require the sacrifice of organisms. Developing non-lethal methods is thus a scientific challenge to enable large scale biomonitoring of wildlife health. We explored blood as a potential non-lethal monitoring tool for metal contamination in brown trout (Salmo trutta fario) as a model species. First, we investigated differences in metal contamination loads (i.e., Cr, Cu, Se, Zn, As, Cd, Pb and Sb) in different blood components (whole blood, red blood cells and plasma). Whole blood was reliable to measure most metals, implying that blood centrifugation is not necessary, thus minimizing sample preparation time. Second, we measured the within individual distribution of metals across tissues (whole blood, muscle, liver, bile, kidney and gonads) to test if blood could be a reliable monitoring tool compared to other tissues. Results show that the whole blood was reliable compared to muscle and bile to measure the levels of metals such as Cr, Cu, Se, Zn, Cd and Pb. This study opens the possibility for future ecotoxicological studies in fish to use blood instead of internal tissues to quantify some metals, thus reducing the negative impacts of biomonitoring on wildlife.

Pengujian COD Analisis Uji Chemical Oxygen Demand (COD) pada Air Limbah Sawit di Dinas Lingkungan Hidup dan Kehutanan Provinsi Bangka Belitung

Indonesia is the largest natural resource producing country in the world, the management of these natural resources requires assistance from various industries. In addition to providing an increase in the regional economy, industry can also cause an increase in waste which can cause environmental damage. Waste that is directly discharged into a water will cause a decrease in water quality, especially for palm oil liquid waste that has not met the specified wastewater quality standards. Chemical Oxygen Demand (COD) is one of the most important parameters in measuring water quality or water contamination load derived from dissolved oxygen in water or waste. Therefore, on this occasion, COD testing will be carried out to determine the level of dissolved oxygen in palm oil liquid waste. From the implementation of the calibration curve of COD testing in wastewater, it was declared accepted because the value of the test correlation coefficient was greater, namely r = 0.9994 than the value of the correlation coefficient set by SNI, namely r = 0.995. While precision data can be accepted if the value of % RPD is not greater than 10% of the test results.&#x0D;

Next-generation Sequencing Results Require Higher Inoculum for Cutibacterium acnes Detection Than Conventional Anaerobic Culture.

Cutibacterium acnes has been described as the most common causative microorganism in prosthetic shoulder infections. Conventional anaerobic culture or molecular-based technologies are usually used for this purpose, but little to no concordance between these methodologies (k = 0.333 or less) has been observed. (1) Is the minimum C. acnes load for detection higher for next-generation sequencing (NGS) than for anaerobic conventional culture? (2) What duration of incubation is necessary for anaerobic culture to detect all C. acnes loads? Five C. acnes strains were tested for this study: Four strains were causing infection and were isolated from surgical samples. Meanwhile, the other was a reference strain commonly used as a positive and quality control in microbiology and bioinformatics. To create inoculums with varying degrees of bacterial load, we began with a standard bacterial suspension at 1.5 x 10 8 colony-forming units (CFU)/mL and created six more diluted suspensions (from 1.5 x 10 6 CFU/mL to 1.5 x 10 1 CFU/mL). Briefly, to do so, we transferred 200 µL from the tube with the highest inoculum (for example, 1.5 x 10 6 CFU/mL) to the following dilution tube (1.5 x 10 5 CFU/mL; 1800 µL of diluent + 200 µL of 1.5 x 10 6 CFU/mL). We serially continued the transfers to create all diluted suspensions. Six tubes were prepared per strain. Thirty bacterial suspensions were tested per assay. Then, 100 µL of each diluted suspension was inoculated into brain heart infusion agar with horse blood and taurocholate agar plates. Two plates were used per bacterial suspension in each assay. All plates were incubated at 37°C in an anaerobic chamber and assessed for growth after 3 days of incubation and daily thereafter until positive or Day 14. The remaining volume of each bacterial suspension was sent for NGS analysis to identify bacterial DNA copies. We performed the experimental assays in duplicate. We calculated mean DNA copies and CFUs for each strain, bacterial load, and incubation timepoint assessed. We reported detection by NGS and culture as a qualitative variable based on the identification or absence of DNA copies and CFUs, respectively. In this way, we identified the minimum bacterial load detected by NGS and culture, regardless of incubation time. We performed a qualitative comparison of detection rates between methodologies. Simultaneously, we tracked C. acnes growth on agar plates and determined the minimum incubation time in days required for CFU detection in all strains and loads examined in this study. Growth detection and bacterial CFU counting were performed by three laboratory personnel, with a high intraobserver and interobserver agreement (κ > 0.80). A two-tailed p value below 0.05 was considered statistically significant. Conventional cultures can detect C. acnes at a load of 1.5 x 10 1 CFU/mL, whereas NGS can detect bacteria when the concentration was higher, at 1.5 x 10 2 CFU/mL. This is represented by a lower positive detection proportion (73% [22 of 30]) for NGS than for cultures (100% [30 of 30]); p = 0.004). By 7 days, anaerobic cultures were able to detect all C. acnes loads, even at the lowest concentrations. When NGS is negative and culture is positive for C. acnes , there is likely a low bacterial load. Holding cultures beyond 7 days is likely unnecessary. This is important for treating physicians to decide whether low bacterial loads necessitate aggressive antibiotic treatment or whether they are more likely contaminants. Cultures that are positive beyond 7 days likely represent contamination or bacterial loads even below the dilution used in this study. Physicians may benefit from studies designed to clarify the clinical importance of the low bacteria loads used in this study at which both methodologies' detection differed. Moreover, researchers might explore whether even lower C. acnes loads have a role in true periprosthetic joint infection.