USEPA Guidelines Research Articles

A pilot study of mercury in Greenland sled dogs in Greenland: civilian versus military owned dogs. Greenlandic: Mississueqqaarneq Qimmit Qimuttut Aavani Meqquinilu Kviksiilveqarnersut.

The Arctic acts as a sink for anthropogenic pollution. The Greenland sled dog is a unique dog breed with ancient ties to humans, but numbers are dwindling, and little is known about their health. We conducted a pilot study of mercury (Hg) accumulation in whole blood from 27 sled dogs owned by civilians in Qaanaaq, NW Greenland, and 123 military owned dogs, NE Greenland. Moreover, Hg hair analyses were conducted on 10 dogs from each location. Whole blood Hg concentration was 2.5-fold higher in civilian dogs (42.6 ± 22.6 ng/g vs. 17.0 ± 11.6 ng/g in Sirius dogs). Blood and hair Hg concentrations correlated well (Pearsons r = 0.76, p < 0.001) and Hg concentrations in hair were 2.8-fold higher in civilian Qaanaaq dogs with 6.28 ± 3.68 μg/g compared to 2.25 ± 1.41 μg/g in Sirius dogs. Hair concentrations in sled dogs were similar to those found in Greenland polar bears and most dogs presented Hg values above toxic levels (US EPA guideline), particularly civilian owned dogs. Results reflect differing diets of the two dog groups, i.e., the feeding regimen of civilian dogs included more marine mammal meat compared to military dogs. More studies are needed to increase our knowledge about exposure of Greenland sled dogsled dogs to environmental contaminants such as Hg and how these toxins may exert adverse health effects to the species as an added stressor to diseases and climate change.

Environmental risk assessment of pesticide use in high-tech agriculture in a valley of northwest Mexico

ABSTRACT A level 1 Environmental Risk Assessment, based on the USEPA guidelines, was conducted using a risk quotient to evaluate the risk of pesticide use. The Culiacan Valley was chosen as study area because of its importance as agricultural zone in northwest Mexico. Records of pesticide applications allowed the critical contaminants to be identified, and a stratified random sampling was carried out to assess pesticide presence in agricultural soils. For each pesticide detected a toxicity reference value was used, and the risk quotient was determined based on the worst possible scenario for five trophic levels. Critical contaminants such as organochlorines, organophosphates and synthetic pyrethroids represented high risk for aquatic and low risk for terrestrial biota. Overall, the study indicates that a more exhaustive risk assessment should be conducted. This information could be useful in the design of better pesticide regulations aimed at mitigating undesirable environmental consequences.

Preferential Stripping Analysis of Post-Transition Metals (In and Ga) at Bi/Hg Films Electroplated on Graphene-Functionalized Graphite Rods

In this study, we introduce a novel electrochemical sensor combining reduced graphene oxide (rGO) sheets with a bismuth–mercury (Bi/Hg) film, electroplated onto pencil graphite electrodes (PGEs) for the high-sensitivity detection of trace amounts of gallium (Ga3+) and indium (In3+) in water samples using square wave anodic stripping voltammetry (SWASV). The electrochemical modification of PGEs with rGO and bimetallic Bi/Hg films (ERGO-Bi/HgF-PGE) exhibited synergistic effects, enhancing the oxidation signals of Ga and In. Graphene oxide (GO) was accumulated onto PGEs and reduced through cyclic reduction. Key parameters influencing the electroanalytical performance, such as deposition potential, deposition time, and pH, were systematically optimized. The improved adsorption of Ga3+ and In3+ ions at the Bi/Hg films on the graphene-functionalized electrodes during the preconcentration step significantly enhanced sensitivity, achieving detection limits of 2.53 nmol L−1 for Ga3+ and 7.27 nmol L−1 for In3+. The preferential accumulation of each post-transition metal, used in transparent displays, to form fused alloys at Bi and Hg films, respectively, is highlighted. The sensor demonstrated effective quantification of Ga3+ and In3+ in tap water, with detection capabilities well below the USEPA guidelines. This study pioneers the use of bimetallic films to selectively and simultaneously detect the post-transition metals In3+ and Ga3+, highlighting the role of graphene functionalization in augmenting metal film accumulation on cost-effective graphite rods. Additionally, the combined synergistic effects of Bi/Hg and graphene functionalization have been explored for the first time, offering promising implications for environmental analysis and water quality monitoring.

Pollution evaluation and health risks assessment of naturally occurring toxic metals in shallow groundwater: A study in southwestern tidal delta of Bangladesh

Pollution evaluation and health risks assessment of naturally occurring toxic metals in shallow groundwater: A study in southwestern tidal delta of Bangladesh

Health risk assessment of metal contamination in Malaysian rice (Oryza sativa): The impact of parboiling on toxic metal reduction prior to cooking

SummaryMetal contamination in rice grains is a critical global issue, posing serious health risks and affecting food safety, especially in countries like Malaysia where rice is a staple food. This study aimed to assess the effectiveness of various cooking treatments, with a focus on parboiling before absorption cooking (PBA), in reducing metal contamination in Malaysian rice. Metal levels were measured using tandem inductively coupled plasma mass spectrometry (ICP‐MS/MS), and health risks were assessed following USEPA guidelines. Parboiling before absorption cooking was found to eliminate 77.9% of toxic metals and 68.4% of essential metals while keeping arsenic (As), cadmium (Cd) and lead (Pb) concentrations below permissible limits. Deterministic health risk assessment indicated that PBA reduced hazard index by 84.5% and lifetime carcinogenic risk (LCR) from As exposure by 88.9%. Hazard quotient for nickel (Ni) and zinc (Zn) remained acceptable for all age groups except for As in children, where LCR exceeded permissible limits. Monte Carlo simulations revealed that over 95% of individuals across age groups faced unacceptable non‐carcinogenic and carcinogenic risks from As exposure, regardless of cooking method. In conclusion, PBA effectively lowered metal concentrations and health risks, especially for toxic metals in rice. Future studies could enhance risk assessment accuracy by analysing metal bioavailability and speciation of metals particularly As.

Assessment of Polycyclic Aromatic Hydrocarbons in Urban Water Bodies: A Study of Rivers and Lakes in Dhaka, Bangladesh

Polycyclic aromatic hydrocarbons (PAHs) pose significant environmental and health risks due to their toxic properties,making their assessment in urban water bodies crucial. This study aims to evaluate the presence of three notable PAHs—anthracene, fluoranthene, and benzo[a]pyrene—in the surface water of three rivers (Buriganga, Meghna, and Turag) andtwo lakes (Hatirjheel and Gulshan) in Dhaka, Bangladesh. High-performance liquid chromatography with fluorescencedetector (HPLC-FD) was employed and validated for PAH determination, using solid phase extraction (SPE) withpreconditioned C-18 SPE cartridge for sample extraction. Calibration showed excellent linearity with correlation coefficient (R²) ≥ 0.999. The limits of detection (LODs) were 200 ng/L for anthracene and 0.63 ng/L for both fluoranthene and benzo[a]pyrene, with corresponding limits of quantification (LOQs) of 660 ng/L and 2.08 ng/L, respectively. Percent recovery was 91.38% for anthracene, 85.49% for fluoranthene, and 95.72% for benzo[a]pyrene, with relative standard deviations (RSD) of 5.27, 17.55 and 2.84%, respectively. Most water samples had PAH levels below detection limits (bdl) such as anthracene (bdl-1789.57 ng/L), fluoranthene (bdl-1309.23 ng/L), and benzo[a]pyrene (bdl-25.17 ng/L), and the detected concentrations were significantly lower than WHO and USEPA guideline values. This indicates a relatively low level of PAHs contamination in the studied water bodies. Dhaka Univ. J. Sci. 72(2): 75-83, 2024 (July)

Gravity‐driven packed bed filter, with copper‐impregnated activated carbon, for continuous water disinfection in absence of electricity

AbstractAvailability of safe drinking water is a major concern in many parts of the world. While many filtration units operating on various principles are available to combat this, most require electricity, which may not be consistently available in such areas. In the present study, we have designed and demonstrated a water disinfection system that can operate purely on gravity, without any electricity. For this, a potassium hydroxide modified copper‐impregnated activated carbon (KOH‐Cu‐AC) hybrid was used as a filter medium for disinfection, because it is less expensive, with performance comparable to previously reported hybrids containing silver. To maintain a constant water flow rate under gravity, during disinfection, a Mariotte bottle was used as the reservoir of the contaminated water. Using this and a constant head between the bottle and the treated water exit point, the required water‐filter contact time of 25 min (for decontamination) is maintained in the filter column, regardless of tank‐fill level. The demonstrated lab‐scale system can perform disinfection of simulated contaminated water (with an initial concentration of 104 CFU mL−1 Escherichia coli), for at least 6 h, with a flow rate of 150 mL h−1. The disinfection performance from the gravity‐based filter was further validated with the conventional pump‐driven filter, used for continuous disinfection of drinking water. Equivalence of results between pump‐ and gravity‐driven operations helps us to eliminate the need for power, without any compromise in disinfection efficacy. Finally, copper concentration from treated water (106 ppb at steady state) remains very well within the safe limit (1000 ppb as per USEPA guideline). Hence, the lab‐scale design of gravity‐based packed bed filter will be useful for domestic and community‐based supply of safe drinking water in resource‐constrained areas, because it eliminated electricity requirement of conventional power‐driven systems.Practitioner Points Cost‐effective KOH‐Cu‐AC hybrid is developed as a disinfection material. Mariotte bottle used for maintaining constant disinfected water flow rate works without any electrical power supply. This system can be used for getting on‐spot, continuous disinfected water supply. The concentration of copper in the treated water is well within the safety limit. It can be applicable in rural and remote areas (no electric power source) as well as natural calamity‐affected areas.

Assessment of metal(loid) and natural radionuclide pollution in surface sediments of an estuary affected by mining and phosphogypsum releases

The prolonged impact over the Tinto River estuary by both the significant pollution by acid mine drainage (AMD) affecting this river and the polluted releases from phosphogypsum (PG) piles has led to the severe environmental degradation of this ecosystem. The aim of this work was to assess the current environmental quality of the Tinto River estuary through the study of the spatial distribution of metal(loid)s and natural radionuclides in the surface sediments from the channel edge. The sediments contain mean concentrations 5–20 times higher than the background values for pollutants such as Zn, As, Cu, Pb, or U, and up to two orders of magnitude higher for P. The studied sediments are heavily polluted by toxic heavy metals and metalloids (Pb, Zn, Cu, and As) according to the US EPA guidelines. Most of the analyzed sediment samples are also strongly polluted by long-lived natural radionuclides, mainly U-isotopes and 210Pb with concentrations up to one order of magnitude higher than unpolluted sediments, mostly due to the contribution by the PG leachates. The enrichment factors (EF) were extremely high (EF > 50) for As and very severe enrichment (25 ≤ EF < 50) for P, Cd, Zn, Cu, and Pb.

Assessment of lead contamination in soil and tap water in daycare facilities in Addis Ababa: implications for children's health

ABSTRACT In recent years, lead poisoning has been recognized as a serious environmental health problem throughout the world, particularly, for children in developing countries. The objective of the study was to investigate the lead level in the water and soil of daycare facilities in Addis Ababa. Graphite furnaces atomic absorption spectrometry was used to analyze the concentration of lead in soil and tap water of 28 daycare centers. The result indicated that the mean levels of lead in soil and water were 0.00237 mg/g and 8.26 μg/L, respectively, which are below the permissible values of 0.1 mg/g and 10 μg/L according to WHO standards. The blood lead levels and exposure to lead in children were calculated using the integrated exposure uptake biokinetic model as per United States Environmental Protection Agency (USEPA) guidelines. The mean blood lead level was 1.78 μg/dL, and the model also predicted that 6.497% of the children in the city may have blood lead levels above the Center for Disease Control recommended reference value of 3.5 μg/dL. Even if the values were below the reference, there is no safe blood lead level since even a small amount can have adverse effects on children.

Occurrence and Risk Assessment of Trihalomethans in Al-Hilla Drinking Water Plant

Trihalomethanes (THMs) have been assessed as potentially carcinogenic for humans and pose a hazard index for drinking water samples. Three water samples were collected namely - raw water, chlorinated water, and drinking water at the central drinking water plant in Babylon province. These samples were analyzed using Gas Chromatography to determine monthly variations in the levels of THM compounds, including Chloroform, Dibromochloromethane, Bromodichloromethane, and Bromoform. The concentrations varied, with high and low values: Chloroform (17.58, 0.47 μg/l), Dibromochloromethane (7.65, 0.08 μg/l), Bromodichloromethane (4.0, 0.03 μg/l), and Bromoform (0.89, 0.15 μg/l) in chlorine basin and supply pipes during the summer and winter months, respectively. A general pattern in the distribution of trihalomethane compounds at all sites was observed: Chloroform (51%) > Bromodichloromethane (21%) > Bromoform (17%) > Dibromochloromethane (11%). During May and June, the ingestion risks for Chloroform and overall THMs surpassed US EPA guidelines. This information is vital for Babylon water authorities assessing water quality’s health implications.

Source apportionment and health risk assessment of PM10 bound carbonaceous and elemental species in the central Himalayas

In this extensive investigation, the sources and health risk assessment of carbonaceous aerosols, as well as the elemental compositions (Ca, Al, Fe, S, K, Mg, Pd, B, Mo, Zn, Ag, Nb, Ga, Cl, Ti, Zr, Na, Cr, Cu, Mn, Cs, P, Y, Sb, Ni, Sn, F, Sr, Br, Pm, U, Pb, Th, Br, Rb, and V) of PM10, were conducted throughout January-December 2021 in Nainital, a central Himalayan region of India. The average annual mass concentration of PM10 was determined to be 64±6 µg m-3. Carbonaceous aerosols (CAs), comprising OC, EC, WSOC, and SOC, exhibited annual averages of 9.3±0.8 µg m-3, 4.9±0.5 µg m-3, 1.5±0.2 µg m-3, 2.7±0.2 µg m-3, and 2.97±0.45 µg m-3, respectively. The elemental composition featured major contributors such as Ca, Al, Fe, S, and K, alongside trace levels of various elements (Mg, Pd, B, Mo, Zn, Ag, Nb, Ga, Cl, Ti, Zr, Na, and Cr). Positive Matrix Factorization (PMF) identified six primary contributors to PM10, each with varying percentage contributions: crustal/soil/road dust, soil re-suspension, combustion, vehicular emissions, industrial emissions, and biomass burning. The health risk assessment revealed elevated Hazard Quotient (HQ) values for Cr and Mn in children, indicating a non-carcinogenic health risk. Adults exposed to high Cr levels may face potential carcinogenic risks, while elements like Al, Pb, Cu, Zn, and Ni pose no health hazards, aligning with USEPA guidelines.

Metal contamination, their ecological risk, and relationship with other variables in surface sediments of urban rivers in a big city in Asia: case study of Hanoi, Vietnam.

Urban rivers are significantly impacted by anthropogenic pressure. This study presents the updated assessment of the concentrations of 11 metals and other variables (pH, total organic carbon (TOC) and nutrients (total nitrogen, total phosphorus, and total silica)) in the sediments of four urban rivers in inner Hanoi city, Vietnam, during the period 2020-2022. The mean concentrations of Fe, Zn, As, and Cr were higher than the permissible values of the Vietnam National technical regulation on the surface sediment quality. Moreover, Zn and Cr were at the severe effect level of the US EPA guidelines for sediment quality. The calculation of pollution indices (Igeo and EF) demonstrated that Mn, Ni, and Fe were from natural sources whereas other metals were from both anthropogenic and natural sources. The ecological risk index revealed that metals in Hanoi riverine sediments were classified at considerable ecological risk. High values of metals, TOC, and nutrients in the sediments of these urban rivers mostly originate from the accumulation of untreated urban wastewater that is enhanced by low river discharge. Our results may provide scientific base for better management decisions to ensure environmental protection and sustainable development of Hanoi city.

Source identification and health risk assessment of particle phase organic compounds in urban and rural areas of Bangladesh

Particle phase organic compounds (PPOCs) constitute a significant portion of suspended organic compounds in the atmosphere, impacting human health. Limited research on sources, seasonal variations, and health effects in Bangladesh motivated this study, where particulate matter samples were collected in Dhaka, Rajshahi, Narayangonj, and Bhola from January 2015 to February 2019. Sixteen PPOCs concentrations were measured using a Gas Chromatography-Mass Spectrometry (GC-MS). Average PPOC concentrations were 11.60 ± 0.1 µgm-3 in Dhaka, 8.69 ± 0.3 µgm-3 in Rajshahi, 11.84 ± 0.4 µgm-3 in Narayangonj, and 7.22 ± 0.2 µgm-3 in Bhola, with 2 to 18 times higher concentrations in winter than monsoon season. Positive Matrix Factorization (PMF) identified major PPOCs sources as diesel exhaust, biomass burning, industrial emissions, and gasoline exhaust. Urban areas were dominated by industrial emissions, while rural regions had significant biomass burning contribution. Health risk assessment indicated a hazard index (HI) of 30.2, signifying severe non-carcinogenic effects, with Dimethoate contributing significantly (32%). The average lifetime cancer risk (2.94 × 10-3) exceeded USEPA guidelines, suggesting heightened cancer risk. Naphthalene posed the highest carcinogenic risk. Given anthropogenic sources and severe health impacts, public awareness and localized research are crucial.

Water Quality and Pollution Status using Principal Component Analysis of Lake Nsezi in Richards Bay, Kwazulu-Natal, South Africa

The water quality of Lake Nsezi in Richards Bay, South Africa was investigated for the possible influence of anthropogenic activities around the lake. Lake water was sampled for a period of one year from May 2014 to May 2015. Physicochemical and bacteriological analysis were compared to regulations of WHO, USEPA and DWAF WQG for aquatic environment and domestic use. Physicochemical parameters measured were within the recommended specifications as per WHO, USEPA and DWAF guidelines for aquatic environment and domestic use at the exception of TDS, Cl and few heavy metals such as Al, Cd, Cu, Fe and Mn. The average content levels for these parameters were: 530±167 mg/L (TDS), 135±92 mg/L (Cl), 0.079±0.11 mg/L (Al), 0.171±0.66 mg/L(Cd), 0.38 ± 0.50 mg/L (Fe), 13.6±15.33 mg/L (Pb). Principal component biplots positively showed some strong and moderate metal loadings of 0.564 (Fe), 0.552 (Pb), 0.928 (Na), 0.893 (Mg), 0645 (Sr) and 0.772 (K) at a variety of sites. Bacteriological parameters content investigated were all above the WHO, USEPA and DWAF guidelines for domestic use for E. coli, heterotrophic plate counts and total coliform counts.

Feasibility of ammonium sulfate recovery from wastewater sludges: Hydrothermal liquefaction pathway vs. anaerobic digestion pathway

This study evaluated two pathways to recover the nitrogen-content of wastewater sludges as ammonium sulfate (AmS) for use as fertilizer. The first pathway entails sludge stabilization by hydrothermal liquefaction (HTL) followed by recovery of AmS from the resulting aqueous product by gas permeable membrane (GPM) separation. The second one entails stabilization of the sludges by anaerobic digestion (AD) followed by recovery of AmS from the resulting centrate by GPM separation. A bench-scale GPM reactor is shown to be capable of recovering >90% of N in the feed. Recoveries of NH3-N in the HTL-pathway ranged 96-100% in 5.5-7.5h at mass removal rates of 0.2-0.3gN/day, yielding 3.3-6.0g AmS/L of feed. Recoveries of 98% were noted in the AD-pathway in 4h at mass removal rates of 0.06-0.97gN/day and a yield of 1.7-2.1g AmS/L of feed. Inductively coupled plasma optical emission spectrometer analysis confirmed that both pathways yielded AmS meeting the US EPA and European region guidelines for land application. The GPM reactor enabled higher nitrogen-recoveries in the HTL-pathway than those reported for current practice of AD followed by ammonia stripping, ion exchange, reverse osmosis, and/or struvite precipitation (96-100% vs. 50-90%). A process model for the GPM reactor is validated using performance data on three different feedstocks.

Trihalomethanes and physicochemical quality of drinking water in Addis Ababa, Ethiopia

Trihalomethanes (THMs) are the most dominant fraction of all the byproducts formed during chlorination of water. Disinfection by product (DBP) formation in water is a function of numerous factors, including pH, temperature, residual chlorine, source water characteristics, and organic matter. No study has determined the THM level in the drinking water supply of Addis Ababa, Ethiopia. A cross-sectional design was conducted to collect water samples in the water supply distribution networks of Addis Ababa, Ethiopia. Twenty-one (21) sampling stations yielded a total of one hundred twenty (120) samples of drinking water. The sample handling and collection procedures were carried out in accordance with USEPA guidelines. A DB-5 capillary column was used to separate the THMs, which were detected using GC-ECD (gas chromatography-electron capture detector). Spectrophotometric and in situ methods were used for physicochemical parameters. Redundancy analysis (RDA) was used for data analysis of trihalomethanes and environmental variables using CANOCO 4.5. The mean concentration of total trihalomethanes in drinking water in Addis Ababa was 76.3μg/L. The concentration of chloroform in the drinking water supply in Addis Ababa, Ethiopia, ranged between 4.03 and 79.4μg/L. The mean total THMs in the Legedadi and Gefersa water supply systems were 77.4μg/L and 69.66μg/L, respectively. The residual chlorine, phosphates, UV absorbance at 254nm, and combined chlorine had positive correlations with THM formation. However, electron conductivity had a negative correlation with THM formation. Chloroform contributed the most to TTHMs in nearly all samples. The residual chlorine, UV absorbance, phosphate and hardness as calcium, and electron conductivity were found to be the main predictors determining the abundance and distribution of trihalomethanes. The monitoring and regulation of the THMs is required on a regular basis to analyse trends and guide the water treatment and distribution system.

Carcinogenic and non-carcinogenic risk assessment of consuming metal-laden wild mushrooms in Nigeria: Analyses from field based and systematic review studies.

This study investigated the potential health risk associated with the consumption of metal-laden mushrooms in Nigeria. Concentrations of Pb, Cd, Cr, Cu, Ni, Zn and Al in wild mushrooms collected from the Nigerian environment were measured using atomic absorption spectrometer. Also, systematic analysis of articles on metal accumulation in mushrooms from Nigeria were obtained from scientific databases. Using hazard model indices, the metal concentration in mushrooms were evaluated for their potential carcinogenic and non-carcinogenic health risk when consumed by adults and children. Zn and Cd, respectively, had the highest and lowest mean concentrations (mg kg-1) in the analysed mushrooms from the field study, while Fe and Co, respectively, had the highest and lowest mean concentrations (mg kg-1) in the systematically reviewed articles. In the field study, the percentage distribution of THQ of the heavy metals greater than 1 was 0% and 42.85% for adults and children respectively. While for the systematic study, 30% and 50% of the heavy metals for adults and children respectively exceeded the limit of 1. The hazard indices obtained from both the systematic and field studies for both age groups were all >1, indicating significant health risk. The findings from both the systematic and field studies revealed that consuming metal-laden mushrooms by adults and children increases the carcinogenic risk to Cd, Cr, and Ni since they exceeded the acceptable limit of 1E-04 stated by USEPA guideline. Based on the findings from the systematic and field studies, it suggests that consuming mushrooms collected from metal polluted substrates increases carcinogenic and non-carcinogenic health risk among Nigerians.

The environmental degradability of DEMNUM, a typical PFPE polymer

The three environmental degradation tests of hydrolysis, indirect photolysis and Zahn-Wellens microbial degradation were conducted according to the OECD and the US EPA guidelines on DEMNUM, a typical linear perfluoropolyether polymer. Low mass degradation products that formed in each test were structurally characterized and indirectly quantified by liquid chromatography mass spectrometry (LC/MS) using a reference compound and an internal standard of similar structure. The degradation of the polymer was assumed to directly correlate with the appearance of lower mass species. The hydrolysis experiment at 50°C showed the appearance of less than a dozen low mass species with increasing pH but at the negligible total estimated amount of ∼2ppm relative to polymer. A dozen low mass perfluoro acid entities also appeared following the indirect photolysis experiment in synthetic humic water. Their maximum total amount was at ∼150ppm relative to polymer. The largest total amount of low mass species formed during the Zahn-Wellens biodegradation test amounted to only ∼80ppm relative to polymer. The Zahn-Wellens conditions tended to produce larger low mass molecules than the ones formed under photolysis. The results from all three tests indicate that the polymer is stable and non-degradable in the environment.

Characterisation of volatile organic compounds in hospital indoor air and exposure health risk determination

Several volatile organic compounds (VOCs) have impacts on human health, but little is known about the concentrations of VOCs in the hospital environment. This study characterised VOCs present in clinical assessment rooms. More than 600 samples of air were collected over 31 months (2017–2020) at two hospital sites in Leicester, United Kingdom, and analysed by comprehensive two-dimensional gas chromatography, making this the largest hospital environment database worldwide on VOCs and first such UK study. The most abundant VOCs found were 2-propanol, ethyl chloride, acetone and hexane, with respective mean concentrations of 696.6 μgm−3, 436.5 μgm−3, 83.9 μgm−3 and 58.5 μgm−3. Acetone, 2-propanol and hexane concentrations were 4, 9 and 30-fold higher respectively compared to similar studies performed in other hospitals. Our results showed that the most frequently detected VOCs, with the highest concentrations, were most likely released by healthcare activities, or related to ingress of vehicle emissions. Hazard quotient (HQ) and cancer risk (CR) were calculated to identify the potential risk of VOCs exposure to the health of healthcare workers. No HQs were measured above 1, compared to inhaled US EPA and OEHHA health guidelines for non-cancer chemicals. For both hospitals, trichloroethylene CR were calculated above 1E-06 by using inhaled US EPA cancer risk values, leading to possible risks to healthcare workers with long-term exposure. More studies of this type, including measurements of VOCs such as formaldehyde that we were unable to include in this study, are needed to better characterise exposures and risks, both to healthcare workers and patients.

Synergistic cancer risk assessment from PM1 bound metals and PAHs in the Indo-Gangetic Region

The atmospheric particulate matter (PM) contains a significant amount of human carcinogens such as metals and Polycyclic Aromatic Hydrocarbons (PAHs). Previous studies have clearly shown that these carcinogens pose serious health issues due to the inhalation of particulate matter. Since the synergistic roles of these carcinogens are rarely considered, these studies frequently underestimate the health risk to humans. The current research aims to bridge this information gap by estimating the synergistic carcinogenic risk assessment owing to PM1 bound metals and PAHs across the densely populated Indo-Gangetic Plain (IGP). The carcinogenic risk assessment was conducted in accordance with the USEPA guidelines on these various PM1 bound components. The Incremental Lifetime Cancer Risk (ILCR) due to heavy metals, such as Lead (Pb) and Chromium (Cr), was found beyond the acceptable limit (> 10−4). The risk due to PM1 bound USEPA PAHs was also significantly higher (> 10−5). This study further estimated the potential toxicity from broad domain of environmental PAHs present in ambient air by considering relevant estimation factors from existing literature. The projected risk from these diverse environmental PAHs was of the order 10−4. Further, source identification of PAHs based on diagnostic isomer ratios revealed that diesel exhaust, biomass burning, and coal combustion are the dominant PAHs sources. Moreover, the exposure to these pollutants is higher in winter and post-monsoon periods. Overall, the synergistic carcinogenic risk found from metals and PAHs was of the order 10−3. In a nutshell, inhalation of PM1 bound heavy metals and PAHs at IGP can result in the development of 1000 cancer cases per million population, which is the highest value compared to other parts of the world. The present study demands immediate policy interventions not only for the reduction of particulate pollution, but also for the reduction of carcinogenic species from the ambient air in order to improve human health.