Angela L. Perez

DGT estimates cadmium accumulation in wheat and potato from phosphate fertilizer applications

Cadmium is a common impurity in phosphatic fertilizers and may contribute to soil Cd accumulation. Changes in total and bioavailable Cd burdens to agricultural soils and the potential for plant Cd accumulation resulting from fertilizer input was investigated. Three year field studies were conducted using three dose levels of cadmium-rich, commercial, phosphate fertilizers applied at four agricultural sites. Labile Cd concentrations, measured using the passive sampling device Diffusive Gradients in Thin Films (Cd(DGT)), increased with increasing fertilizer application rates. Cd also accumulated in the edible portion of wheat and potato crops grown at the sites, and showed strong positive dose response with fertilizer treatment. Regression models were calculated for each site, year, and for individual crops. Model comparisons indicated that soil physical and chemical parameters in addition to soil Cd fractions, were important determinants of Cd(DGT). Significant factors contributing to Cd(DGT) concentrations were Cd from fertilizer input (Cd(fertilizer)), pH, cation exchange capacity (CEC), and total recoverable Cd (Cd(total)). Important factors used to determine Cd concentrations in wheat grain (Cd(wheat)) and in potato (Cd(potato)) were as follows: Cd(wheat):Cd(fertilizer), and Cd(DGT); and Cd(potato):Cd(fertilizer), Cd(DGT), % O.M. The effective concentration, C(E), calculated from DGT did not correlate well with Cd(wheat) or with Cd(potato). Direct measurements of Cd(DGT) correlated better with Cd found in edible plant tissue. The modeling approach presented in this study helps to estimate Cd accumulation in plant tissue over multiple years and in distinct agricultural soil systems.

Triclosan occurrence in freshwater systems in the United States (1999–2012): A meta-analysis

Recently, concern has grown regarding the presence of triclosan (TCS) in waters because of its potential for causing ecological and human health effects. The authors present a statistical analysis of TCS concentrations reported between 1999 and 2012 in freshwater environments in the United States and provide a comparison with available health-based and aquatic guidance values. Data from 46 peer-reviewed and unpublished investigations from 45 states and 1 US territory were included in the meta-analysis, encompassing the following coded water types: untreated (raw wastewater), effluent (wastewater treatment plant effluent), effluent-impacted environmental, environmental, and finished drinking water (total n = 2305). Triclosan was most frequently detected in untreated waters (92% detection frequency; mean ± standard error, 11 270 ± 2925 ng/L; n = 237), but concentrations were significantly reduced in effluent waters (83% detection frequency 775 ± 311 ng/L; n = 192, α = 0.05). Triclosan concentration in effluent-impacted environmental waters (62% detection frequency; 130 ± 17 ng/L; n = 228) was not significantly reduced from effluent waters but was significantly greater than TCS in environmental waters not classified as effluent impacted (11% detection frequency; 13 ± 3 ng/L; n = 1195). In finished drinking water, TCS was largely undetected (1% detection frequency; 4 ± 2 ng/L n = 453), suggesting that for the United States, drinking water is not an appreciable source of TCS exposure. In posttreatment waters, average TCS concentrations were below part-per-billion levels. Although no US regulatory standard exists for TCS in aquatic systems, comparison of averages reported in the present study with a predicted-no-effect concentration (PNEC) of 500 ng/L showed that 5.3% of effluent-impacted environmental waters were above the PNEC for changes in algal biomass, while only 0.25% of environmental waters surpassed this value.

Chemical assessment state of the science: Evaluation of 32 decision-support tools used to screen and prioritize chemicals

The last decade has seen an increased focus on evaluating the safety and sustainability of chemicals in consumer and industrial products. In order to effectively and accurately evaluate safety and sustainability, tools are needed to characterize hazard, exposure, and risk pertaining to products and processes. Because many of these tools will be used to identify problematic chemistries, and because many have potential applications in various steps of an alternatives analysis, the limitations and capabilities of available tools should be understood by users so that, ultimately, potential chemical risk is accurately reflected. In our study, we examined 32 chemical characterization tools from government, industry, academia, and non-governmental organizations (NGOs). The tools we studied were diverse, and varied widely in their scope and assessment. As such, they were separated into five categories for comparison: 1) Screening and Prioritization; 2) Database Utilization; 3) Hazard Assessment; 4) Exposure and Risk Assessment; and 5) Certification and Labeling. Each tool was scored based on our weighted set of criteria, and then compared to other tools in the same category. Ten tools received a high score in one or more categories; 24 tools received a medium score in one or more categories, and five tools received a low score in one or more categories. Although some tools were placed into more than one category, no tool encompassed all five of the assessment categories. Though many of the tools evaluated may be useful for providing guidance for hazards - and, in some cases, exposure - few tools characterize risk. To our knowledge, this study is the first to critically evaluate a large set of chemical assessment tools and provide an understanding of their strengths and limitations.

Airborne asbestos exposures associated with gasket and packing replacement: a simulation study and meta-analysis.

Exposures to airborne asbestos during the removal and installation of internal gaskets and packing associated with a valve overhaul were characterized and compared to published data according to different variables (e.g., product, equipment, task, tool, setting, duration). Personal breathing zone and area samples were collected during twelve events simulating gasket and packing replacement, clean-up and clothing handling. These samples were analyzed using PCM and TEM methods and PCM-equivalent (PCME) airborne asbestos concentrations were calculated. A meta-analysis was performed to compare these data with airborne asbestos concentrations measured in other studies involving gaskets and packing. Short-term mechanic and assistant airborne asbestos concentrations during valve work averaged 0.013f/cc and 0.008f/cc (PCME), respectively. Area samples averaged 0.008f/cc, 0.005f/cc, and 0.003f/cc (PCME) for center, bystander, and remote background, respectively. Assuming a tradesman conservatively performs 1-3 gasket and/or packing replacements daily, an average 8-h TWA was estimated to be 0.002-0.010f/cc (PCME). Combining these results in a meta-analysis of the published exposure data showed that the majority of airborne asbestos exposures during work with gaskets and packing fall within a consistent and low range. Significant differences in airborne concentrations were observed between power versus manual tools and removal versus installation tasks. Airborne asbestos concentrations resulting from gasket and packing work during a valve overhaul are consistent with historical exposure data on replacement of asbestos-containing gasket and packing materials involving multiple variables and, in nearly all plausible scenarios, result in average airborne asbestos concentrations below contemporaneous occupational exposure limits for asbestos.

Soil-diffusive gradient in thin films partition coefficients estimate metal bioavailability to crops at fertilized field sites†

Field trials in four distinct agricultural soils were conducted to examine changes to total recoverable and labile soil Cd and Ni concentrations with applications of commercial phosphate fertilizers. The edible portion of wheat and potato crops grown at the field plots were analyzed for recoverable Cd and Ni. Total recoverable Ni and Cd concentrations in agricultural soils increased by 10 and 22%, respectively, each year of the study at recommended application rates. Labile Cd and Ni were measured using diffusive gradients in thin films (DGT), a passive sampling device reported to estimate the plant bioavailable metal fraction. Nickel concentrations measured with DGT did not significantly change with treatment nor did they change over time. Cadmium concentrations measured with DGT increased with application rate and over time from 2003 to 2005, then decreased in 2006. Wheat grain Cd concentrations and Cd and Ni levels in tubers increased significantly with fertilizer treatment level. Grain and tuber Cd values exceeded the minimal risk levels for chronic oral exposure. At agronomical P-fertilizer application rates, 25% of plant samples deviated from the Cd minimal risk levels. The present study reports the use of K(d-BIO), defined as the ratio of total recoverable metal to DGT measured metal, as a significant indicator of crop metal accumulation in the edible portion. The K(d-BIO) values were well correlated with both grain and tuber concentrations over multiple growing seasons. Results from long-term field trials emphasize K(d-BIO) as a dynamic term that provides risk characterization information about the fate of Cd and Ni in aged, fertilized agricultural soils and crops.

Child and adult exposure and health risk evaluation following the use of metal- and metalloid-containing costume cosmetics sold in the United States

Abstract Costume cosmetics (lipstick, body paints, eyeshadow) were analyzed for metals using inductively coupled plasma mass spectrometry (ICP‐MS). Sb was detected in all samples (range: 0.12–6.3 mg/kg; d.f. 100%), followed by Pb (<0.15–9.3 mg/kg), Ni (<0.20–6.3 mg/kg), Co (<0.5–2.0 mg/kg); with d.f. 80% each, Hg (<0.00015–0.0020 mg/kg; d.f. 50%) and As (0.53 mg/kg, d.f. 10%). Ingestion and dermal exposures were estimated for child‐ and adult‐intermittent and adult‐occupational users. Adult‐occupational users exceeded the U.S. EPA Reference Dose (RfD) for Sb and the CA Proposition 65 maximum allowable dose level (MADL) for Pb was exceeded for all user scenarios. The Pb dose from body paint was sufficient to raise blood lead levels (BLL) in all user scenarios above baseline BLLs from 0.2 &mgr;g/dL to 1.9 &mgr;g/dL per the Adult Lead Model (ALM) and child Integrated Exposure Uptake Biokinetic (IEUBK) blood Pb models. Change in BLL was less than 1 &mgr;g/dL amongst the child and adult‐intermittent users, the benchmark change in BLL developed for health risk assessments for children. Adult‐occupational users exceeded the CA Proposition 65 NSRL intake value of 15 &mgr;g/day, which corresponds to an increase of 1.2 &mgr;g/dL above baseline levels using ALM. Exposure of occupational users of costume cosmetics should be evaluated further to prevent unnecessary metal exposure. HighlightsSb, Pb, Ni, Co, Hg, and As were detected from below detection to 9.3 mg/kg wet weight.Oral ingestion accounted for over 99% of all metal intake.The Pb dose from body paint was predicted to raise BLLs above baseline in all users.Change in BLL was less than 1 &mgr;g/dL amongst the child and adult‐intermittent users.Concentrations of the dermal sensitizer, Ni, were below international guidance values.

Airborne asbestos exposures associated with gasket and packing replacement: a simulation study of flange and valve repair work and an assessment of exposure variables.

A simulation study was conducted to evaluate worker and area exposure to airborne asbestos associated with the replacement of asbestos-containing gaskets and packing materials from flanges and valves and assess the influence of several variables previously not investigated. Additionally, potential of take home exposures from clothing worn during the study was characterized. Our data showed that product type, ventilation type, gasket location, flange or bonnet size, number of flanges involved, surface characteristics, gasket surface adherence, and even activity type did not have a significant effect on worker exposures. Average worker asbestos exposures during flange gasket work (PCME=0.166 f/cc, 12-59 min) were similar to average worker asbestos exposures during valve overhaul work (PCME=0.165 f/cc, 7-76 min). Average 8-h TWA asbestos exposures were estimated to range from 0.010 to 0.062 f/cc. Handling clothes worn during gasket and packing replacement activities demonstrated exposures that were 0.71% (0.0009 f/cc 40-h TWA) of the airborne asbestos concentration experienced during the 5 days of the study. Despite the many variables considered in this study, exposures during gasket and packing replacement occur within a relatively narrow range, are below current and historical occupational exposure limits for asbestos, and are consistent with previously published data.

A meta-analysis of airborne asbestos fiber concentrations from work with or around asbestos-containing floor tile

ABSTRACT In this meta-analysis, exposures to airborne asbestos during work with or around floor tiles were characterized according to several variables: study, sample type, activity, and task. Personal breathing zone, bystander, and area sample exposure concentrations were differentiated and compared against current occupational exposure limits to asbestos. In total, 22 studies, including 804 personal, 57 bystander, and 295 area samples, were included in the analysis. The arithmetic mean airborne fiber concentrations were 0.05, 0.02, and 0.01 f/cm3 for personal, bystander, and area samples, respectively. Arithmetic mean time-weighted-average fiber concentrations over an 8-h working day were 0.02 and 0.01 f/cm3 for personal and bystander samples, respectively. Phase contrast microscopy (PCM) personal airborne fiber concentrations were highest for maintenance activities, followed by removal and installation. Tasks that involved buffing or burnishing, scoring or snapping, and scraping or lifting had the highest personal PCM concentrations, while stripping floor tile and removing it with chemical solvent had the lowest concentrations. Exposures associated with handling asbestos floor tiles, under working conditions normally encountered, do not generally produce airborne concentrations at levels that exceed the current OSHA PEL nor do they appear to approach the threshold cumulative asbestos dose concentrations that have been previously associated with an increased risk of asbestos-related disease.

The challenge of predicting problematic chemicals using a decision analysis tool: Triclosan as a case study

Manufacturers lack a reliable means for determining whether a chemical will be targeted for deselection from their supply chain. In this analysis, 3 methods for determining whether a specific chemical (triclosan) would meet the criteria necessary for being targeted for deselection are presented. The methods included a list-based approach, use of a commercially available chemical assessment software tool run in 2 modes, and a public interest evaluation. Our results indicated that triclosan was included on only 6 of the lists reviewed, none of which were particularly influential in chemical selection decisions. The results from the chemical assessment tool evaluations indicated that human and ecological toxicity for triclosan is low and received scores indicating that the chemical would be considered of low concern. However, triclosans peak public interest tracked several years in advance of increased regulatory scrutiny of this chemical suggesting that public pressure may have been influential in deselection decisions. Key data gaps and toxicity endpoints not yet regulated such as endocrine disruption potential or phototoxicity, but that are important to estimate the trajectory for deselection of a chemical, are discussed. Integr Environ Assess Manag 2017;13:198-207.