USEPA Method Research Articles

Estimation of Particulate Emission Generation in Palm Oil Mill Boiler

The palm oil industries in Malaysia has been positively growth throughout the year, for it sustainable approach in terms of production and environmental protection. However, this industry also producing considerable amount of particulate emission from the process of burning its biomass waste of palm fibre and shell in the boiler. This study present a method to estimate the particulate emission that are being generated from the boiler. The method were done by analyzing the proximate analysis value of the ash content of palm fibre and shell found in this study. The particulate emission were physically collected from five palm oil mill boilers with boiler capacity ranging from 18-45 tonne/hour. The particulate stack fly ash was collected from the stack gas downstream of a multi-cyclones particulate arrestor according to the USEPA Method 17- Determination of particulate matter emissions from stationary sources. Meanwhile the sample of palm fibre and shell were collected to determine the proximate value. The estimation were then being further analyzed according to the particulate emission that were obtained by the real-stack sampling. In summary, the average moisture content, ash content, volatile matter and fixed carbon for palm shell found in this study are 19.3 ± 5.7%, 2.79 ± 2.2%, 74.3 ± 3.0, and 11.3 ± 4.3, respectively.). The average particulate concentration for these five mills is 2.2±0.9g/Nm3 and the air pollution control requirement are between 64 and 96% with reference to Clean Air Regulations 2014 of 0.15g/Nm3 which is very high to be achieve. It also can be estimated that 26% of the ash generated from the combustion of palm fibre and shell in palm oil mill boiler are being released at the stack.

Risk Assessment for Co-contaminated Soil Including As and Hg in the Vicinity of Abandoned Metal Mine

Objectives:In Korea, about 2,000 abandoned mine area has been polluted by harmful waste such as mine tailing, waste rock and acid mine drain without prevention facility. Mine waste contains high concentrations of various hazardous metallic and nonmetallic materials. Also, it can be a source of pollution for nearby soil, rivers, and ground water. Heavy metals may exist in ecosystems for a long time and may be taken by the residents through crops and drinking water. In this study, human risk assessment for heavy metal contamination was carried out.Methods:About the 564 soil samples were analyzed for heavy metal. The risk assessment of polluted soils was carried out in accordance with guideline of Korea Soil Environment Conservation Act. It was implied with hazard identification, exposure assessment, toxicity assessment, and risk characterization.Results and Discussion:The number of exceed sites for the worried level of soil concentration were 185 for As, 3 for Hg, 7 for Zn, 1 for Pb, 1 for Cu. Soil contact was the biggest impact on adults and children for carcinogenic risk followed by crop intake, soil intake, and soil inhalation. Non-carcinogenic risk for adults, were in order of crop intake > soil intake > soil contact > outdoor air inhalation (volatilization) > ground water intake and soil inhalation. For children, it was in the order of soil intake > crop intake > soil contact > outdoor air inhalation (volatilization) > ground water intake > soil inhalation.Conclusion:The carcinogenic purification target concentration for the site was determined to be 7.17 mg / kg level of arsenic, considering adult and child concentrations. However, carcinogenic purification target concentration by arsenic dermal absorption carcinogenic coefficients (SF<sub>abs</sub>) of USEPA method was 20.08 mg/kg, therefore requiring research for domestic risk assessment factor.

Combination of compositional data analysis and machine learning approaches to identify sources and geochemical associations of potentially toxic elements in soil and assess the associated human health risk in a mining city

Mining activities change the chemical composition of the environment and have negative reflection on people’s health and there is no single measure to deal with adverse consequences of mining activities, as each case is specific and needs to be understood and mitigated in a unique way. In this study, the combination of compositional data analysis (CoDA), k-means algorithm, hierarchical cluster analysis applied to reveal the geochemical associations of potentially toxic elements (PTE) in soil of Alaverdi city (Armenia) (Ti, Fe, Ba, Mn, Co, V, Pb, Zn, Cu, Cr, Mo, As). Additionally, to assess PTE-induced health risk, two commonly used approaches were used. The obtained results show that the combination of CoDA and machine learning algorithms allow to identify and describe three geochemical associations of the studied elements: the natural, manmade and hybrid. Moreover, the revealed geochemical associations were linked to the natural pattern of distribution of the element concentrations including the influence of the natural mineralization of the parent rocks, as well as the emission from the copper smelter and urban management related activities. The health risk assessment using the US EPA method demonstrated that the observed contents of studied elements are posing a non-carcinogenic risk to children in the entire territory of the city. In the case of adults, the non-carcinogenic risk was identified in areas situated close to the copper smelter. The Summary pollution index (Zc) values were in line with the results of the US EPA method and indicated that the main residential part of the city was under the hazardous pollution level suggesting the possibility of increase in the overall incidence of diseases among frequently ill individuals, children with chronic diseases and functional disorders of vascular system. The obtained results indicated the need for further in-depth studies with special focus on the synergic effect of PTE.

Distributions of enterococci and human-specific bacteriophages of enterococci in a tropical watershed.

The bacteriophages of E. faecalis strains AIM06 (DSM100702) and SR14 (DSM100701) have previously been validated as human-specific microbial source tracking (MST) markers in Thailand. In this study, their spatial and temporal distribution in a freshwater river was investigated for the first time (n=48). The abundance of enterococci as a standard microbial water quality parameter was evaluated by both the qPCR detection assay with primers and a hydrolysis probe according to the US EPA Method 1611 and the US EPA Method 1600 membrane filtration culture method. AIM06 and SR14 phages were detected by a double layer agar assay and were present in 87.5% and 81.3% of all samples with a co-presence of 92.9% of phage-positive samples. After spiking the representative phages, the ranges of recovery efficiencies were 57.9-99.6% and 49.6-99.9% (n=48) for AIM06 and SR14 phages, respectively. The absolute abundance of AIM06 and SR14 phages ranged from 0.25 to 221.94 and from 0.25 to 76.66PFU/100mL, respectively. Enterococci DNA copies and CFU were detected in all samples ranging from 3.24 to 6.32 log10 copies/100mL and 100.00 to 1593CFU/100mL, respectively. Enterococci in the qPCR assay also showed a moderate correlation with the culture method. The AIM06 and SR14 phage results indicated continuing human faecal pollution along the river with no significant different levels among stations. Interestingly, the higher levels of enterococci in downstream stations for both the qPCR and culture methods along with the significant correlation with other faecal indicator organisms and non-human MST markers implied non-human faecal pollution. In conclusion, this study provides insightful information that could lead to effective water quality management and public health risk reduction from exposure to faecally-contaminated water.

Efficient multiresidue determination method for 168 pharmaceuticals and metabolites: Optimization and application to raw wastewater, wastewater effluent, and surface water in Beijing, China

New analytical methods are needed to efficiently measure the growing list of priority pharmaceuticals in environmental samples. In this regard, a rapid, sensitive, and robust method was developed for quantitation of 168 pharmaceuticals and pharmaceutical metabolites using solid-phase extraction (SPE) and liquid chromatography with tandem mass spectrometry. The extraction protocol and instrumental efficiency were specifically addressed to increase analytical workload and throughput. The optimized protocols, which are five times more efficient than US EPA Method 1694, enabled analyte recoveries that ranged from 77% to 117% for 162 analytes with method quantitation limits (MQLs) as low as 0.1 ng L−1. To verify the suitability of the improved analytical method for environmental samples, 24-h composite samples of raw wastewater and wastewater effluent, along with downstream surface water, were analyzed. Overall, 143/168 target compounds were identified in at least one of the samples, and 130/168 analytes were present at concentrations above their MQLs. The total mass concentration of the measured analytes decreased by 93% during wastewater treatment. The analyte concentrations in the wastewater effluent were comparable to those measured in surface water 1 km downstream of the wastewater discharge point. Ultimately, the comprehensive method will serve as an important tool to inform the occurrence, fate, transport, and toxicity of a large suite of priority pharmaceuticals and pharmaceutical metabolites in natural and engineered systems.

Historical deposition of trace metals in a marine sapropel from Mangrove Lake, Bermuda with emphasis on mercury, lead, and their isotopic composition

Sapropel is an organic-rich sediment formed under conditions that can result in sequestration of trace metals. Here, we determined the concentration of total mercury (Hg), lead (Pb), and 16 other metals (Al, Ba, Ca, Cd, Cr, Cs, Cu, Fe, Li, Mn, Ni, Sr, Tl, U, V, Zn) in a sapropel core from Mangrove Lake, Bermuda that dated back nearly two millennia. The purpose was to assess historical patterns of metal deposition on this geographically remote island in the North Atlantic Ocean. Two sediment cores were collected from Mangrove Lake using a modified piston corer. Cores were age-dated with a Bayesian statistical age-depth model using a multiproxy approach relying on 210Pb and radiocarbon dates. Total Hg was determined following US EPA Method 7473 using a direct mercury analyzer. Other metals were determined by sector field ICP-MS following a microwave-assisted strong-acid digestion. Stable isotope measurements of Hg and Pb were used to better track sources of these contaminants. Sapropel Hg concentrations were low (~ 50 ng g−1) from about 1000 AD to 1600 AD, followed by a slow rise in concentration until a high point of 209 ng g−1 in the early nineteenth century. Hg levels then returned to ~ 70 ng g−1, still elevated above baseline levels, before a final sharp rise in the mid-1900s to 430 ng g−1. Pb, Zn, Cu, Cr, and Ba had similar patterns, with Pb isotope ratios showing early natural fluctuations followed by the greater influence of pollution sources. Mercury stable isotope data also show the influence of anthropogenic sources during the 1800s and suggest a mix of atmospheric, terrestrial, and possibly marine-derived Hg inputs to the lake. The vertical distribution of elements and isotopes reveals changes in deposition through time associated with pollution from industrialization, and, possibly, volcanic activity, seawater intrusion, intense hurricane events, and local pollution from ship and fortress building. Overall, this study demonstrates that organic-rich sapropel provides a good historical record of metal contamination, and that Bermuda, despite its remote location, had metal deposition profiles much like the records of other sediment cores from around the world.

Characteristics and Applications of Sewage Sludge Biochar Modified by Ferrous Sulfate for Remediating Cr(VI)‐Contaminated Soils

Background. Soil contamination by hexavalent chromium is becoming a main environmental concern in China. This study developed a sewage sludge biochar modified by FeSO4 (CHBC) as a new reductant for Cr(VI)‐contaminated soil. The effectiveness of CHBC‐stabilized Cr(VI)‐contaminated soil was investigated. Methods. Typical industrial Cr(VI)‐contaminated soil in China was chosen as the medium. The total and Cr(VI) contents of the contaminated soil were 1014.6 and 973.5 mg/kg, respectively. The effectiveness of the Cr(VI)‐contaminated soil stabilized by CHBC was investigated by the leaching test (US EPA method 1312), the simplified bioaccessibility extraction test (US EPA 2007 protocol and British Geological Survey), alkaline digestion (US EPA method 3060A), sequential extraction (BCR sequential extraction procedure), X‐ray diffraction, and the risk assessment code test. Results. Results show that CHBC substantially reduced the leachability and Cr(VI) content of the contaminated soil. The leachability and content of Cr(VI) were lower than the thresholds of the Environmental Quality Standards of Soil in China for civil reuse and the China Environmental Quality Standards of surface water for civil use when the soil was stabilized with 10% dosage of CHBC. Conclusion. CHBC is highly efficient in stabilizing Cr(VI) and can effectively reduce the leachability and bioavailability of Cr in contaminated soil and thus feasible for stabilizing Cr(VI)‐contaminated soil and shows potential for application in the field.

Helminth eggs assessment of fecal sludge in urban area of Bandung, Indonesia

Soil-transmitted helminth eggs present to be non-excludable parameter for water quality and sanitation since they are linked to public health concern. Unfortunately, investigation of helminth eggs presence in wastewater is very limited in Indonesia. The result of previous study confirmed helminth eggs presence in irrigation water and land samples in agriculture field in urban area of Bandung. Inappropriate of wastewater treatment system and reuse of unsafe wastewater are the reason why helminth egg were found in agriculture area. Therefore, this study was conducted to get better understanding of helminth eggs presence in wastewater especially in fecal sludge of the city. Samples were collected from desludging trucks servicing residential and non-residential septic tanks from total 17 areas. Modification of US EPA method is used to analyse and enumerate the viable helminth eggs. There are big variations amount of helminth egg in samples from different area, from 4 eggs/L to 617 eggs/L. We found more than 10 species of helminth eggs. Hookworm egg counts were higher than those of Fasciola hepatica and Ascaris lumbricoides. This study also showed that septic tank inefficient for reducing helminth eggs presence in fecal sludge and for fulfilled recommendation of WHO for safe water reuse.

Geochemical and health risk assessment of fluoride and nitrate toxicity in semi-arid region of Anantapur District, South India

Abstract This paper reports to the fluoride and nitrate concentration in groundwater resources of the semi-arid region of Anantapur district, South India, and its related potential health risk assessment issues with the resident peoples. For this purpose, 50 groundwater samples were analyzed for hydrochemical parameters including major ions, fluoride and nitrate. The results revealed that most of the groundwater samples are alkaline in nature. Hydrochemical type of groundwater in the study area mainly Na+-K+-Cl−-SO42− and few samples belong to Na+-K+-HCO3−. Non carcinogenic health risks due to fluoride and nitrate exposure through consumption of groundwater were assessed using the USEPA method. In the study area groundwater samples, fluoride and nitrate concentration ranges from 1.2 to 5.9 mg/L and 36 to 92 mg/L. Based on these results, 86% of fluoride (>1.5 mg/L) and 94% of the nitrate (>45 mg/L) in groundwater samples exceed the permissible limit. The Total Hazard Index (THI) quotients for adults, children and infants had health hazards (THI > 1) in 98%, 88%, and 80% of samples, respectively. Hence, proper precautionary measures have to be taken to control health risk in this area.

Evaluation of dioxin-like polychlorinated biphenyls in fish of the Caspian Sea

Dioxin-like polychlorinated biphenyls (DL-PCBs) have toxic properties for humans. The innovation of this study was that for the first time in Iran, 12 DL-PCBs concentration in 5 fish species: Rutilus frisii kutum kanesky, Chelon saliens, Vimba vimba, Cyprinus carpio and Oncorhynchus mykiss, from 5 coastal areas of the Caspian Sea (125 samples), were investigated. DL-PCBs extraction was in accordance to USEPA method 1668 revision A and carry out by chromatography columns modified with silica gel. DL-PCBs concentration were measured by HRGC (Agilent 6890 Series, Agilent Technologies, USA) coupled with HRMS AutoSpec Ultima NT–HRGC/HRMS (Micromass, USA), equipped with the HP-5MS 30 m × 0.25 mm × 0.25 μm column (Agilent Technologies) and helium as carrier gas. The mean concentration of DL-PCBs in samples ranged 232 ± 16–1156 ± 14 pg/g fat, that was in accordance with the Joint FAO/WHO Expert Committee on Food Additives and European Standards. The highest concentration was in Cyprinus carpio of Bandar Anzali, and lowest obtained in samples from Chalous. However, based on fish consuming and fish originating from the fishing area the health risk evaluation to estimate the potential consequences of chronic exposure to DL-PCBs for consumers is recommended and effective measure for health risk reduction.

Assessment of regulated halo-acetic acids disinfection by-products and their concomitant risks in Ahmadu Bello University Zaria drinking water supply

Abstract The conventionally treated drinking water supplied to the Ahmadu Bello University community was assessed for its levels of regulated halo-acetic acids. This is because the Ahmadu Bello University water treatment plant uses calcium hypochlorite in the chlorinated disinfection of its treated water during the treatment process. Longitudinal sampling was undertaken along the treatment and distribution stages of drinking water supply in the community. Between 2008 and 2010, 252 samples were collected and analysed for the regulated halo-acetic acids in accordance with USEPA Method 551.1 (1995) using Methyl Tert-Butyl Ether (MTBE) as extractant and a calibrated Agilent Gas Chromatograph measured their concentrations. All the regulated halo acids recorded their highest concentrations in the chlorinated water sample and these decreased towards house-level water sample except for dichloroacetic acid which increased from the booster station sample with 3.2500E-03±5.8452E-03 mg/L to the house level sample with 3.2511E-03±9.1256E-05 mg/L. The total regulated halo-acetic acid (THAAs) concentrations also decreased from the chlorinated sample concentration of 1.8324E+00±8.1252E-02 mg/L. to the house level concentration of 4.8826E-01±2.8735E-02 mg/L, a situation likely attributable to the turbulent flow during distribution resulting in the increased volatility of the acids in the distribution system. Although not specifically regulated by the Nigerian National Standards, the concentrations of these acids at house level (4.8826E-01±2.8735E-02 mg/L) drinking water is more than the maximum permissible limits of these regulated acids under the USEPA drinking water standard’s maximum contaminant level (MCL) of 0.060 mg/L. In view of their implication in increased risk of cancer and other effects including problems of the reproductive system, these acids’ concentration in household drinking water need to be rigorously monitored and regulated to minimize their risk to health.turbulent flow during distribution resulting in the increased volatility of the acids in the distribution system. Although not specifically regulated by the Nigerian National Standards, the concentrations of these acids at house level (4.8826E-01±2.8735E-02 mg/L) drinking water is more than the maximum permissible limits of these regulated acids under the USEPA drinking water standard’s maximum contaminant level (MCL) of 0.060 mg/L. In view of their implication in increased risk of cancer and other effects including problems of the reproductive system, these acids’ concentration in household drinking water need to be rigorously monitored and regulated to minimize their risk to health.

Measuring the Condensable Particle Matter from a Stationary Source

With the retrofitting of coal-fired power plants and steel plants for ultra-low-emission control, the concentration of filterable particles (FPM) from these sources is decreasing gradually. The condensable particle matter (CPM) draws more attention. The understanding of CPM emission concentration and chemical characteristics is still limited. There has been no standard determination method of CPM in China until now. In this study, three methods, including the dry impinger method (US EPA method 202), indirect dilution method, and direct dilution method, are discussed and compared in measuring CPM emissions from coal-fired power plants, coke-making plants and sintering plants. The results show that method 202 overestimates the emissions of CPM, due to the fact that the gaseous HCl or SO2 dissolves into condensable liquid and cannot be completely eliminated by N2 purging after sampling. Instead, CPM measured using the indirect dilution method better represents its real emission levels into the atmosphere.

Seasonal and spatial variation in total trihalomethane formation potential in groundwater in Tulkarm and Hebron, Palestine

Water disinfection using processes such as chlorination is required to kill bacteria and harmful biological components. During chlorination, organic components in water react with chlorine, forming harmful disinfection by-products such as trihalomethanes (THMs). These compounds are very harmful to humans, animals, and plants. Thus, the concentration of these substances in groundwater as well as the seasonal variation in this concentration are of immense interest to scientists. A headspace method was used to analyze trihalomethanes (THMs) using an Agilent 6890N GC/MS. Five-milliliter water samples were employed in this analysis. Separation was performed on a J&W-VRX column. A selected ion monitoring (SIM) mode that complied with US EPA method no. 501 was developed for the detection of four THM species. Quantification and method validation were performed using external standard calibration. The total trihalomethane formation potentials (TTHMFPs) in four groundwater wells in the summer and the winter were found to be below the maximum limits specified by environmental agencies. Seasonal variations were more pronounced for the formation of chloroform (CF), which was the dominant THM species formed. The fraction of the TTHMFP that was due to CF increased in the winter in groundwater samples from the Anabta (2), Anabta (3), and Al Rehya wells, whereas the fraction of the TTHMFP that was due to CF was almost the same in summer (43.2%) and in winter (40.3%) in the groundwater samples from the Al Fawar well. These findings are important for the appropriate regulation of THM levels and for achieving a better understanding of environmental public health and epidemiological issues concerning disinfection by-products in Palestine.

1,4-Dioxane contamination of German drinking water obtained by managed aquifer recharge systems: Distribution and main influencing factors

1,4-Dioxane, a cyclic ether that has been classified as a class 2B carcinogen by the US-EPA, is a substance of growing environmental concern because of its abundant occurrence in surface waters worldwide. Its high polarity and low biodegradability hamper its retardation in aquifer systems. Previous investigations in Germany have shown that 1,4-dioxane is already widely distributed in rivers and can be found in groundwater at contamination sites. Therefore, the present study shall provide an overview of the Germany-wide distribution of 1,4-dioxane in finished drinking water (FDW) obtained by managed aquifer recharge (MAR) systems. Thus, we investigated the 1,4-Dioxane levels in FDW obtained by MAR, such as river bank filtration (RBF) or artificial groundwater recharge (AGR), in regions that are supplied by surface water bodies (mainly rivers) with already known 1,4-dioxane contaminations. In total, 125 FDW samples and 33 samples of corresponding surface waters were analyzed for 1,4-dioxane content using solid phase extraction followed by gas chromatography–mass spectrometry (SIM-mode) using a slight modification to US-EPA method 522. About 80% of the investigated FDW samples contained 1,4-dioxane at levels exceeding the limit of quantification (0.034 μg/L); the maximum value was 2.05 μg/L. However, a maximum concentration of 3 μg/L was obtained in the surface water samples. Three main factors were associated with elevated levels of 1,4-dioxane in the FDW: A significant 1,4-dioxane contamination of the associated surface water, the application of RBF instead of AGR, and the proportion of available unpolluted groundwater and/or reservoir water blended in the individual waterworks. The results show that 1,4-dioxane should be critically monitored during FDW production by means of MAR not only in Germany. The findings are also of relevance to neighboring countries depending on the same river systems and for research in the field of small mobile substances in drinking water production in general.

Mercuric pollution of surface water, superficial sediments, Nile tilapia (Oreochromis nilotica Linnaeus 1758 [Cichlidae]) and yams (Dioscorea alata) in auriferous areas of Namukombe stream, Syanyonja, Busia, Uganda.

The mercury content and the contamination characteristics of water, sediments, edible muscles of a non-piscivorous fish (Oreochromis nilotica Linnaeus 1758 [Cichlidae]) and yams (Dioscorea alata) from Namukombe stream in Busia gold district of Uganda were evaluated. Human health risk assessment from consumption of contaminated fish and yams as well as contact with contaminated sediments from the stream were performed. Forty-eight (48) samples of water (n = 12), sediments (n = 12), fish (n = 12) and yams (n = 12) were taken at intervals of 10 m from three gold recovery sites located at up, middle and down sluices of the stream and analyzed for total mercury (THg) using US EPA method 1631. Results (presented as means ± standard deviations) showed that water in the stream is polluted with mercury in the range of < detection limit to 1.21 ± 0.040 mg/L while sediments contain mean THg from < detection limit to 0.14 ± 0.040 ugg−1. Mean THg content of the edible muscles of O. nilotica ranged from < detection limit to 0.11 ± 0.014 ugg−1while D. alata contained from < detection limit to 0.30 ± 0.173 ugg−1mean THg. The estimated daily intake ranged from 0.0049 ugg−1day−1 to 0.0183 ugg−1day−1 and 0.0200 ugg−1day−1 to 0.0730 ugg−1day−1 for fish consumed by adults and children respectively. The corresponding health risk indices ranged from 0.0123 to 0.0458 and 0.0500 to 0.1830. Estimated daily intake was from 0.0042 ugg−1day−1 to 0.1279 ugg−1day−1 and 0.0130 ugg−1day−1 to 0.3940 ugg−1day−1 for D. alata consumed by adults and children respectively. The health risk indices recorded were from 0.011 to 0.320 and 0.033 to 0.985 for adults and children respectively. The mean THg content of the sediments, edible muscles of O. nilotica and D. alata were within acceptable WHO/US EPA limits. About 91.7% of the water samples had mean THg above US EPA maximum permissible limit for mercury in drinking water. Consumption of D. alata grown within 5 m radius up sluice of Namukombe stream may pose deleterious health risks as reflected by the health risk index of 0.985 being very close to one. From the pollution and risk assessments, mercury use should be delimited in Syanyonja artisanal gold mining areas. A solution to abolish mercury-based gold mining in the area needs to be sought as soon as possible to avert the accentuating health, economic and ecological disaster arising from the continuous discharge of mercury into the surrounding areas. Other mercury-free gold recovering methods such as use of borax, sluice boxes and direct panning should be encouraged. Waste management system for contaminated wastewater, used mercury bottles and tailings should be centralized.

Extending the Holding Time for Agricultural Water Testing EPA Method 1603 for Produce Growers

Agricultural water is a known vector for the transfer of foodborne pathogens onto fresh produce. Development of pre-harvest and post-harvest microbial profiles of agricultural water used by fresh produce growers, processors, and holdings is a requirement under the Food Safety Modernization Act Produce Safety Rule. One of the United States Environmental Protection Agency (US EPA) approved agricultural water testing methods is US EPA Method 1603, which requires no greater than a 6-h time frame between the collection of the water sample and initiation of analysis. This 6-h timeframe is unrealistic for many produce growers due to there being few laboratories certified to conduct testing and the geographic location of the farms. Agricultural water samples (n = 101) from well water and surface water were collected from 60 different farms to determine if holding samples for 24 h yielded significantly more generic Escherichia coli (E.coli) than 6 h using EPA 1603 method. A total of 32 samples were found contaminated with generic E. coli. Of these positive samples, surface water accounted for 87.5% of the samples (n = 28). There was no significant disparity between populations of generic E. coli at 6- and 24-h sample-test time interval (p &gt; 0.05). These results provide evidence that the sample-test time interval can be extended to 24-h time, which makes quantitative generic E. coli testing for agricultural water as mandated by the FSMA Produce Safety Rule more accessible to growers.

Enteric viruses in municipal wastewater effluent before and after disinfection with chlorine and ultraviolet light.

In Ontario, Canada, information is lacking on chlorine and ultraviolet (UV) light disinfection performance against enteric viruses in wastewater. We enumerated enteroviruses and noroviruses, coliphages, and Escherichia coli per USEPA methods 1615, 1602, and membrane filtration, respectively, in pre- and post-disinfection effluent at five wastewater treatment plants (WWTPs), with full-year monthly sampling, and calculated log10 reductions (LRs) while WWTPs complied with their monthly geometric mean limit of 200 E. coli/100 mL. Modeling of densities by left-censored estimation and Bayesian inference gave very similar results. Polymerase chain reaction (PCR)-detected enteroviruses and noroviruses were abundant in post-disinfection effluent (mean concentrations of 2.1 × 10+4-7.2 × 10+5 and 2.7 × 10+4-3.6 × 10+5 gene copies (GC)/L, respectively). Chlorine or UV disinfection produced modest LRs for culture- (0.3-0.9) and PCR-detected enteroviruses (0.3-1.3), as well as noroviruses GI + GII (0.5-0.8). Coliphages and E. coli were more susceptible, with LRs of 0.8-3.0 and 2.5, respectively. Sand-filtered effluent produced significantly higher enteric virus LRs (except cultured enteroviruses). Coliphage and human enteric virus densities gave significantly positive correlations using Kendall's Tau test. Enteric viruses are abundant in wastewater effluent following routine chlorine or UV disinfection processes that target E. coli. Coliphages appear to be good indicators for evaluating wastewater disinfection of enteric viruses.

Bioaccumulation of PCDD/Fs in foodstuffs near Bien Hoa and Da Nang airbases: assessment on sources and distribution.

In this survey, food items were collected from vicinities of Bien Hoa and Da Nang airbase and determined for polychloro-dibenzo-dioxins and polychloro-dibenzo-furans (PCDD/Fs) to assess their accumulation, distribution in the local food items, and risk of PCDD/F exposure through consumption of the local foods. Dioxin compounds were determined using isotope dilution method which is slightly modified from US-EPA method 1613B. The dioxin concentration was the highest in fish followed by eggs, chicken, meat (pork and beef), and vegetables. Particularly, in Bien Hoa airbase, the mean concentrations of dioxin on TEQ and lipid basis (except for vegetables) were 26pg/g for fish, 13pg/g for eggs, 20pg/g for chicken, 4.5pg/g for meat, and 0.34pg/g fresh wt for vegetables. In Da Nang airbase, the mean levels of dioxin on TEQ and lipid basis were slightly lower, 12.9pg/g for fish, 8.7pg/g for eggs, 5.9pg/g for chicken, 6.7pg/g for meat, and 0.17pg/g for vegetables. It has been interesting to observe that free-range chicken expose to higher level of dioxin than caged chicken. In some free-range chicken, the portion of 2,3,7,8-TCDD was relatively high and implying recent exposure to dioxin.

Distribution of fluoride contamination in drinking water resources and health risk assessment using geographic information system, northwest Iran

This paper considers exposure to the concentration of fluoride in drinking water resources of Showt city in West Azerbaijan Province in, Iran, and its related potential health risk assessment issues to the resident populations. For this purpose, 88 drinking water samples were analyzed in 2016 by using the spectrophotometric method. Non-carcinogenic health risks due to F exposure through consumption of drinking water were assessed using the US EPA method. In addition, the associated zoning maps of the obtained results were presented using a geographic information system (GIS). The results indicated that fluoride concentration in drinking water ranged from 0.0 to 5.5 mg L−1 of the study area. Based on this research, 36.36% of the samples had a fluoride level higher than the permissible level, 13.63% had less than the permissible limit, and 50% of the samples had a level within the optimum limit of 0.5–1.5 mg L−1. The Hazard Quotient index (HQ) for children, teenager and adults had health hazards (HQ > 1) in 54.55%, 31.82%, and 22.73% of samples, respectively. Groundwater resources having a risk of more than one were located in the villages of Khilajajam, Kolos, and Shorboulagh. So, in these study areas, there are potential risks of dental and skeletal fluorosis.

Mercury Levels in Human Hairs and Nails of Traditional Gold Miners in Butana-Area East of Sudan

The aim of this study is to assess the mercury (Hg) exposure level of gold miners in Butana mining area, in Eastern, Sudan. To achieve this goal 40 biological samples such as hair and nails (20 for each) samples were obtained randomly from the gold miners in 10 sampling sites and analyzing using US EPA Method 7473. A direct mercury analyzer (DMA-80; Milestone Inc., Shelton, CT, USA) was adopted to determine the mercury levels.