Lead Concentrations In Water Research Articles

Water Quality Analysis and Risk Assessment of Potential Toxic Elements in Selected Surface Water Around Mining Sites in Abuakwa South Municipal, Ghana

ABSTRACTSurface water quality at Abuakwa South Municipal has received threats from surrounding mining communities, which are becoming a major concern to the public. As a result, this study aimed to assess water quality by examining the concentration of lead (Pb), cadmium (Cd), and zinc (Zn) pollution in surface water. Fifteen samples were obtained from surface water using a 1.5 L plastic bottle. The mean concentrations of Pb and Cd were above WHO guidelines of 0.01 and 0.003 mg/l, respectively, except for Zn which was below the stipulated limit of 3.0 mg/l. The geochemical process model shows that Cd, Pb, and Zn are adsorbing (released from the drainage to the surrounding environment) in sites 1 and 3 whereas Pb is desorbing (added to the drainage) in site 2. A hazard quotient greater than 1 was recorded for Cd in adults through the ingestion route of exposure at all the sites. Cancer risk also shows that the inhabitants are at risk through the ingestion route of exposure. The findings of this study suggest intake of water draining within the vicinity is unsafe and poses severe health risks.

Assessment of Cadmium, Chromium, and Lead Concentrations in Water, Bank Soil, Sediment, Plants, and Fish in Bagega Lake, Zamfara State, Northwest-Nigeria

Assessment of Cadmium, Chromium, and Lead Concentrations in Water, Bank Soil, Sediment, Plants, and Fish in Bagega Lake, Zamfara State, Northwest-Nigeria

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.

Household Water Lead and Hematologic Toxic Effects in Chronic Kidney Disease

The consequences of low levels of environmental lead exposure, as found commonly in US household water, have not been established. To examine whether commonly encountered levels of lead in household water are associated with hematologic toxicity among individuals with advanced kidney disease, a group known to have disproportionate susceptibility to environmental toxicants. Cross-sectional analysis of household water lead concentrations and hematologic outcomes was performed among patients beginning dialysis at a Fresenius Medical Care outpatient facility between January 1, 2017, and December 20, 2021. Data analysis was performed from April 1 to August 15, 2023. Concentrations of lead in household water were examined in categorical proportions of the Environmental Protection Agency's allowable threshold (15 μg/L) and continuously. Hematologic toxic effects were defined by monthly erythropoiesis-stimulating agent (ESA) dosing during the first 90 days of incident kidney failure care and examined as 3 primary outcomes: a proportion receiving maximum or higher dosing, continuously, and by a resistance index that normalized to body weight and hemoglobin concentrations. Secondarily, hemoglobin concentrations for patients with data prior to kidney failure onset were examined, overall and among those with concurrent iron deficiency, thought to increase gastrointestinal absorption of ingested lead. Among 6404 patients with incident kidney failure (male, 4182 [65%]; mean [SD] age, 57 [14] years) followed up for the first 90 days of dialysis therapy, 12% (n = 742) had measurable lead in household drinking water. A higher category of household lead contamination was associated with 15% (odds ratio [OR], 1.15 [95% CI, 1.04-1.27]) higher risk of maximum monthly ESA dosing, 4.5 (95% CI, 0.8-8.2) μg higher monthly ESA dose, and a 0.48% (95% CI, 0.002%-0.96%) higher monthly resistance index. Among patients with pre-kidney failure hemoglobin measures (n = 2648), a higher household lead categorization was associated with a 0.12 (95% CI, -0.23 to -0.002) g/dL lower hemoglobin concentration, particularly among those with concurrent iron deficiency (multiplicative interaction, P = .07), among whom hemoglobin concentrations were 0.25 (95% CI, -0.47 to -0.04) g/dL lower. The findings of this study suggest that levels of lead found commonly in US drinking water may be associated with lead poisoning among susceptible individuals.

Bioaccumulation of Lead and Mercury in Water, Sediment, and Fish Samples of Baraila Lake, Vaishali, Bihar.

In the current study, a protected subtropical wetland in Bihar (India), Baraila Lake, was investigated for heavy metal (Pb and Hg) status. These metals tend to bioaccumulate in fish, posing a concern to human health. This study reported the concentration of lead and mercury in water, sediment, and fish muscles of Baraila Lake in the year 2022. The samples were collected from pre-monsoon and post-monsoon seasons at four sampling locations, i.e., Loma, Dhulwar, Chakaiya, and Kawai Baraila, and were analyzed in triplicates. Lead concentration in water samples of all four sites of Baraila Lake observed during pre-monsoon and post-monsoon season exceeded the permissible limit for drinking water, while the mercury concentration of all sites was under the permissible limit in both seasons as prescribed by WHO. The extent of elemental pollution was evaluated using the Geo-accumulation index (Igeo), contamination factor (CF), contamination degree (Cd), ecological risk factor (Er), and the potential ecological risk index (Ri). Lead concentration in fish muscles of both seasons exceeded the permissible limit, while the concentration of mercury exceeded in Xenentodon cancila (0.55 ± 0.07µg/g) during the pre-monsoon season. Also, estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) were calculated in different fish muscles to assess potential human health risks. A higher THQ value of 1.303 was observed in carnivore fish during the pre-monsoon season.

Risk assessment of four toxic heavy metals in terrestrial and aquatic ecosystems around BSCIC tannery industrial estate of Savar, Dhaka,Bangladesh.

The shifting of tannery industries from Hazaribagh to Savar adjacent to Dhaleshwari River might have inevitable adverse impacts, especially the heavy metal contamination of both terrestrial and aquatic ecosystems. The study was carried out to investigate the concentrations of four heavy metals in the soil, water, and plant samples collected from around Dhaleshwari River adjacent to the Bangladesh Small & Cottage Industries Corporation Tannery Industrial Estate, Dhaka. This study revealed that average concentrations of cadmium and chromium in soil exceeded the maximum permissible limit of World Health Organization (1996) and average concentrations of lead, cadmium, and chromium in water exceeded the maximum permissible limit of World Health Organization (2011) and Environmental Conservation Rules (1997). The average concentrations of lead, cadmium, and chromium in the roots and shoots of both Eichhornia crassipes and Cynodon dactylon exceeded the maximum permissible limit of Food and Agriculture Organization/ World Health Organization (2016). Ecological risk assessment using indices model for soil pollution indicated that soil is mostly contaminated with cadmium and chromium which can pose strong ecological risk Health risk assessment using indices model for water pollution revealed the high degree of contamination and unacceptable non-carcinogenic risk and carcinogenic risk for adults as well as children through ingestion of water. Average bioconcentration factor and bioaccumulation factor were higher in Eichhornia crassipes than Cynodon dactylon for lead, cadmium, and chromium. Average translocation factor was also higher in Eichhornia crassipes for all the metals except cadmium. It is suggested remedial and mitigation measures be instituted to control environmental degradation of the newly established Tannery Industrial Estate.

Zn-doped CeO2 nanorod based dispersive solid phase micro-extraction of lead in water, black pepper, lentils and tea samples

In this work, pristine CeO2 and Zn-doped CeO2 nanorods were prepared through facile hydrothermal process and characterized. The Zn- doped CeO2 was first used for dispersive solid phase micro extraction (d-SPµE) of lead in water and food. The conditions affecting d-SPµE of lead were optimized. They were pH, adsorption/elution contact time, eluent type/volume/concentration, interfering ion effects and sample volume. The sample pH, eluent concentration/volume and sample volume were 3, 2 mol L−1 HCl/1 mL and 60 mL, respectively. The adsorption/desorption kinetics of the developed d-SPµE were very fast, and the extraction time was only 30 s (30 s for adsorption and without vortexing for elution). The preconcentration factor (PF) and limit of detection (LOD) of the d-SPµE for lead were 60 and 2.0 µg L−1, respectively. The RSD% (n=5) of the extraction method was found to be ≤ 3.0%. The high tolerable interfering ion concentrations were obtained. The sorbent could be used for 46 times. The method was confirmed with analyses of NW-TMDA 54.6 Lake water, SPS-WW1 Batch 114 Wastewater and NIST 1573a Tomato Leaves certificate reference materials. The trace lead concentrations in wastewater, dam water, river water, sea water, tea, lentils, and black pepper were determined by d-SPµE-FAAS.

Water Quality of Roof-Harvested Drinking Water Tanks in a Rural Area near a Gold and Copper Mine: Potential Health Risk from a Layer of Metal-Enriched Water and Sediment

This study investigated the drinking water quality of house water tanks that harvested roof runoff in a rural area surrounding a large copper and gold mine in Central Western New South Wales (NSW). Water was sampled from (1) the tops of water tanks, (2) the bottoms of water tanks, and (3) kitchen taps. Water samples collected from the bottoms of tanks were turbid with suspended sediment. Concentrations of metals (lead, nickel, arsenic and manganese) from bottom-of-tank water samples often exceeded Australian drinking water guidelines. Overall, 37.2% of samples from bottoms of tanks exceeded arsenic guidelines (<10 µg L−1). The mean concentration of lead in water from bottoms of tanks was 695 µg L−1, with 18.6% of these samples exceeding lead guidelines (<10 µg L−1) by >100 times. Our results highlight the risk of contaminated water and sediment at the bottoms of tanks. Further investigation of private household drinking water tanks is recommended for properties in other rural areas, including areas with and without nearby mining activity. We describe a layer of contaminated water and sediment at the bottoms of water tanks, near the water outlet, which is a potential contamination pathway and substantial health risk for house water supplies.

Effect of Community Water Service on Lead in Drinking Water in an Environmental Justice Community.

Multiple recent studies have found elevated lead (Pb) concentrations in tap water in U.S. homes relying on unregulated private wells. The main Pb source is dissolution from household plumbing, fixtures, and well components. Here, we leverage a natural experiment and citizen science approach to evaluate how extending community water service to an environmental justice community relying on private wells affects Pb in household water. We analyzed Pb in 260 first-draw kitchen tap water samples collected by individual homeowners over a 5-month period in residences that did and did not connect to the community system. Before the community water system was extended, 25% of homes had Pb > 15 μg/L (the U.S. regulatory action level for community water systems) in first-draw water samples. Pb was significantly correlated with nickel (ρ = 0.61), zinc (ρ = 0.50), and copper (ρ = 0.40), suggesting that corrosion of brass fittings and fixtures is the main Pb source. Among homes that connected to the community system, Pb decreased rapidly and was sustained at levels well below 15 μg/L over the study period. Overall, connecting to the municipal water supply was associated with a 92.5% decrease in first-draw tap water Pb.

TOXICITY TEST OF WASTE OIL BEFORE AND AFTER TREATMENT USING PHYTOREMEDIATION ON BIOINDICATORS

Silugonggo River is a river that crosses Juwana District, Pati Regency, Central Java, which empties into the Java Sea. Industrial activities and workshops around the Silugonggo River cause river water to become polluted with used oil.. Even though many people around the river use the Silugonggo River for daily activities, one example is as a place to find fish for side dishes and traded.. The purpose of this study was to determine the concentration of lead in river water contaminated with used oil waste and the LC50 value of 0-96 hours against bioindicators, namely tilapia (Oreochromis niloticus), before and after being processed using phytoremediation. This research phase includes: 1) toxicity tests before treatment consisting of: preliminary tests with waste concentrations of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100%, and actual tests with waste concentrations of 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24%; 2) The process of treating waste oil with phytoemidiation using water hyacinth and kale plants is tested for plant weight variations. Plant weight variations are 200 grams, 300 grams, 400 grams, and 500 grams, and the process of processing waste oil is carried out continuously; 3) Post-treatment toxicity test consisting of: preliminary test with waste concentrations of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100%, and actual tests with waste concentrations of 42, 43, 44, 45, 46, 47, 48, 49, 50, and 51%. The results showed that the effective weight in reducing lead in water hyacinth plants and kale plants was 500 grams with lead weight being <0.0058 mg / L (under Quality Standards according to the Decree of the Government Regulation of the Republic of Indonesia Number 82 of 2001 concerning Water Quality Management and Water Pollution Control). The LC50 value of 96 hours of waste oil before processing is 19.66%. The LC50 value 96 hours after processing is 46.69%.

Modulatory effect of magnesium hydroxide-nanoparticles on lead-induced toxicity in river Clarias gariepinus near mining site

Effluents emerging from unprotected local mining activities pollute the nearby rivers containing aquatic lives. Advent of nanotechnology however, supposedly helps in removal of water contaminants and as well make waste water remediation possible. To this effect, Clarias gariepinus from rivers near mining site at Ijero-Ekiti, Ekiti-State, Nigeria were collected and exposed to 62.5, 125 and 250mg/L suspension of 10nm magnesium hydroxide nanoparticles (MgOHNPs) for 14-days under semi-static conditions. The suspected lead concentration in the river water was estimated using atomic absorption spectrophotometer while the quality of the river water was also examined. Clarias gariepinus collected were sacrificed and alterations in their biochemical and hematological indices were evaluated. The results showed that water sample from river I exhibit highest (0.033ppm) lead concentration while water sample from river III has the lowest (0.006ppm) lead concentration relative to their proximity to the mining site. Besides, the collected fishes demonstrated significant (P<0.05) concentration dependent increase in some biochemical indices and no observable significant alteration in hematologic state of the fishes at tested doses. Hence, results from this study suggest that toxic lead effluent from local mining activities may have elevated lead concentration levels in nearby rivers while exposure to MgOHNPs could evoke alterations in physiological system of the inhabiting aquatic lives.

Health Risks from Intake and Contact with Toxic Metal-Contaminated Water from Pager River, Uganda.

Pollution of water resources is one of the major impediments to the realization of Sustainable Development Goals, especially in developing countries. The aim of this study was to investigate the physicochemical quality and potentially toxic element (lead and cadmium) concentrations in surface water sampled from Pager River, a tributary of the Nile River in Northern Uganda. Water samples (n = 18) were taken from six different points upstream (A, B, and C) and downstream (D, E, and F) of the river and analyzed following standard methods for their physiochemical properties. Atomic absorption spectroscopy was used to quantify lead and cadmium concentrations. Human health risks from ingestion and dermal contact with potentially toxic metal-contaminated water were calculated. The results obtained indicated that the mean temperature (27.7 ± 0.5-29.5 ± 0.8 °C), turbidity (40.7 ± 2.1-50.1 ± 1.1 NTU), lead (0.296 ± 0.030-0.576 ± 0.163 mg/L) and cadmium (0.278 ± 0.040-0.524 ± 0.040 mg/L) occurred at levels that surpassed their permissible limits as per World Health Organization guidelines for drinking water. Human health risk assessment showed that there are potential non-cancer risks from the ingestion of water from Pager River by adults, as the total hazard quotients were greater than one. These results emphasize the urgency to restrict the dumping of wastes into the river to minimize chances of impacting the Nile River, which flows northwards to the Mediterranean Sea. Further studies should perform routine monitoring of the river during both dry and wet seasons to establish the spatiotemporal variations of physicochemical, microbial, and trace metal profiles of the river and the associated health risks.

Trace metal load of two urban wetlands with varied catchment activities in Ghana.

This study compared Lead (Pb), Chromium (Cr), Copper (Cu), Zinc (Zn), Mercury (Hg), Arsenic (As) and Cadmium (Cd) concentrations in sediment, water, and biota at Vaughan Dam which receives limited sewage effluent discharge from residential areas, and Korle Lagoon which receives industrial effluents, electronic waste, garages-spill oil and a host of others in addition to residential sewage effluent discharge. Samples were analyzed with Atomic Absorption Spectrometer. The results showed that concentrations of trace metals were generally higher in the sediment, water, and plants from the Korle Lagoon but only Cu in the sediment of Korle Lagoon showed a significantly high concentration. The similarities in the rank orders of the metal concentrations together with the dominance of Zn and Pb in most compartments of the wetlands indicated major differences did not exist in the contaminant input to the two wetlands except electronic waste recycling and disposal that resulted in significantly high copper concentrations in the sediment of Korle Lagoon. No evidence of biomagnification was determined along the food chains of the Vaughan Dam and the Korle Lagoon for all the metals studied.The Tilapia zilli from Vaughan Dam, the only biota that is regularly consumed from the wetlands, had Cr, Cu, Pb, Cd, Hg, and As concentrations above FAO/WHO permissible limits and therefore pose a health risk to consumers.

Achromotrichia due to hypocupremia in a dog

A five-year-old, intact, female, brown Labrador retriever was presented for loss of hair color (achromotrichia). Clinical and blood examinations revealed no significant abnormalities, except for a considerably reduced serum copper measurement. This has been described in dogs and cattle as achromotrichiosis due to hypocupremia. Interference of intestinal copper absorption due to an increased lead concentration in the drinking water was assumed to be the cause. The dog’s haircoat became brown again after serving tap water as drinking water and adding a copper supplement.

Lead Reduction on Polluted Water and Sediment through The Use of Anadara granosa shells and Monostroma nitidum Biological Filters

Industrial waste water treatment holds a very vital role in filtering toxic materials and improving the quality of industrial waste water before being released into public waterways, so that the water ecosystem balance can be maintained. This study aims to identify Pb concentration on polluted water and sediment from an offshore oil drilling area near Camplong Beach, Madura, and also make efforts to find out the potential Anadara granosa shells and Monostroma nitidum seaweed biofilters that exist in that place so as to suppress the adverse effects of toxic materials that arise. The method used was experimental research design that aims to systematically obtain information to describe a lead concentration on polluted water and sediment, and also evaluate the presence of A. granosa shells and M. nitidum as a potential biological filter. The results of the analysis of lead in A. granosa shells, M. nitidum biofilter, water, and sediment indicated that there was a significant correlation, where the shells of A. granosa and M. nitidum can absorb lead until 36.59% and 8.79%, respectively, from which the initial concentrations of lead in sediment and water were 5.57±1.58 and 0.004±0.001 mg/kg respectively. The existence of algicidal substances of HDTA, ALA, and ODTA from M. nitidum can suppress the growth of dinoflagellatas of Chattonella marina. The quantification analysis of fatty acid composition showed that M. nitidum is dominated by PUFA as much as 66% of total fatty acid, and has algicidal substances of HDTA, ALA, and ODTA of 61.53 mg/100 g.

Improved Decision Making for Water Lead Testing in U.S. Child Care Facilities Using Machine-Learned Bayesian Networks.

Tap water lead testing programs in the U.S. need improved methods for identifying high-risk facilities to optimize limited resources. In this study, machine-learned Bayesian network (BN) models were used to predict building-wide water lead risk in over 4,000 child care facilities in North Carolina according to maximum and 90th percentile lead levels from water lead concentrations at 22,943 taps. The performance of the BN models was compared to common alternative risk factors, or heuristics, used to inform water lead testing programs among child care facilities including building age, water source, and Head Start program status. The BN models identified a range of variables associated with building-wide water lead, with facilities that serve low-income families, rely on groundwater, and have more taps exhibiting greater risk. Models predicting the probability of a single tap exceeding each target concentration performed better than models predicting facilities with clustered high-risk taps. The BN models' Fβ-scores outperformed each of the alternative heuristics by 118-213%. This represents up to a 60% increase in the number of high-risk facilities that could be identified and up to a 49% decrease in the number of samples that would need to be collected by using BN model-informed sampling compared to using simple heuristics. Overall, this study demonstrates the value of machine-learning approaches for identifying high water lead risk that could improve lead testing programs nationwide.

Zap the Lead Problem: Cost-effective and Immediate Electrochemical Pipe Scale Accelerator

The Electrochemical Pipe Scale Accelerator (EPSA) rapidly reduces lead (Pb) concentration in water by up to 99% by electroplating an insoluble and non-conductive lead phosphate or aluminum oxide scale. Twenty-Two million Americans, 120 million Europeans, and 500,000 Canadian households are at risk of lead-contaminated water. Unfortunately, traditional scale passivation can take up to years to form and deteriorate under a chemical change in water (Flint, Michigan, 2014). Replacing pipes can be expensive, costing $250/foot, and the U.S. government up to 47 billion dollars to replace all pipes. The objective was to engineer a low-cost and rapid device that could reduce Pb concentration below the “Lead and Copper rule.

Spherical hydroxyapatite nanoparticle scaffolds for reduced lead release from damaged perovskite solar cells

Perovskite solar cells continue to attract interest due to their facile preparation and high power conversion efficiencies. However, the highest efficiency perovskite solar cells inevitably contain lead, which raises concerns over contamination of drinking water when a solar module is broken and then flooded. We previously showed that conventional synthetic hydroxyapatite (HAP) nanoparticles could capture some of the lead from broken solar cells, but the amount of lead released was well above the safe drinking water level. Here, we modify the HAP synthesis to prepare new spherical-HAP (s-HAP) nanoparticles with a 60% increase in the Pb absorption capacity. We blend s-HAPs with TiO2 nanoparticles to construct mixed scaffolds and investigate their effect on (FAPbI3)0.97(MAPbBr3)0.03 solar cell performance and lead capture. Replacement of 80% of the TiO2 nanoparticles with s-HAP causes the power conversion efficiency to increase from 18.61% to 20.32% as a result of decreased charge carrier recombination. Lead contamination of water from devices subjected to simulated hail damage followed by flooding is shown to decrease exponentially with increasing s-HAP content. The lead concentration in water after 24 h is below the US safe water drinking limit.

Water quality criteria and ecological risk assessment of lead (Pb) in China considering the total hardness of surface water: A national-scale study

Site-specific water quality criteria considering hydrochemical conditions are needed for zoning control of environmental risks. However, the differences in water quality parameters between regions have not been fully considered in the current research on water quality criteria and risk assessment of lead. In this study, lead concentration and total hardness (TH) data of surface water in 13 major river basins and 31 administrative regions in China were collected. Based on the normalization of the TH of the toxicity data, the short-term and long-term water quality criteria of lead in China's surface water in the specific TH condition (100 mg/L) were derived using the species sensitivity distribution method, which were 90.7 μg/L and 2.1 μg/L, respectively. Furthermore, this study provided general derivation formulas for the water quality criteria based on the TH of surface water and obtained the site-specific criteria for different regions/basins in China. On this basis, an ecological risk assessment considering the TH was proposed for the first time. The results showed that there was a clear risk of lead in the Pearl River Basin and the rivers in Zhejiang-Fujian. The southern coastal provinces were at an unacceptable risk level, although the lead concentrations in the surface water were medium; the opposite was true in northern China, which meant that a high concentration of lead did not necessarily pose a high ecological risk and about 25 % of the variation in the predicted risk can be explained by the TH in Monte Carlo simulation.

Effects of pipeline geometry, sample volume, and flow rate on pb monitoring outcomes in copper pipe drinking water supply systems

Pb in drinking water is one of the main sources of Pb in human bodies. Besides excess lead incidents caused by lead service lines, Pb contamination in non-lead pipe systems (e.g. copper and PVC) is also on the rise. Brass fixtures and lead-solder connections are the primary sources of lead in non-lead systems, which cause intermittent peaks of Pb at the consumer tap. The concentrations of lead in tap water depend on pipeline geometry, sampling methods, and the characteristic of the pipe flow. Using a 3-dimensional computational fluid dynamics model, this study analyzes the Pb concentration variations at taps of copper water supply systems. The turbulent diffusion and shear flow dispersion are fully simulated in the model to provide the most accurate prediction. Water parcels containing lead (clouds) are formed adjacent to lead sources during stagnation and are then dispersed with the flow of water through the pipe when the tap is opened. The geometry of the pipeline has a significant impact on the monitored Pb levels. The complex flow condition in elbow areas leads to a more intense mixing of lead ions. Therefore, the Pb levels at consumer taps in complex plumbing systems in high-rise buildings are higher than in straight pipelines. When the sampling flow rate is large, the peak height of Pb is slightly higher due to higher turbulent intensity. Pb concentrations in sequential samples are predicted with sample volumes of 50, 250, 500, and 1000 mL. Lead levels may be diluted significantly when samples are taken in large volumes (e.g. 500 mL or 1 L), resulting in an underestimation of Pb levels at taps. A sample volume of 250–500 mL is recommended in sequential sampling programs on non-lead service lines in order to identify Pb sources.