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Posted by on in Centers of Excellence
In early 2017, a group of scientists met at the International Agency for Research on Cancer (IARC) in Lyon, France to evaluate the carcinogenicity of welding fume. This evaluation included a review of relevant exposure data, studies of cancer in humans, studies of cancer in experimental animals, toxicokinetic data, and information on disease in susceptible populations. Based on this review, the IARC working group determined that  “sufficient evidence” exists that welding fume is a human lung carcinogen (Group 1) (Lancet 2017). Previously, IARC had classified welding fume as being “possibly carcinogenic to humans” (Group 2B) based on available data at the time that the mixture was evaluated in 1989 (IARC 1990).

A complicating factor in reclassifying welding fume is its complexity. Generally, welding fume is a mixture of metal fumes (i.e., iron, manganese, chromium, nickel, silicon, titanium) and gases (i.e., carbon monoxide, ozone, argon, carbon dioxide). Welding fume can contain varying concentrations of individual components that are classified as human carcinogens, including hexavalent chromium and nickel. However, the presence of such metals and the intensity of exposure to each differ significantly according to a number of variables, including the type of welding technique used and the composition of the base metal and consumable (IARC 1990). Nonetheless, IARC did not differentiate between these variables in its decision.

What actions should be taken as a results of IARC’s reclassification? 

1.       Update hazard communication programs to include information regarding welding fume now being classified as a Group 1 carcinogen.

2.       Update exposure assessments for welding fume, including both for welders and nearby workers who are not engaged in welding. Given that NIOSH guidance for carcinogens aims to keep exposures as low as feasible, documenting and characterizing the potential for exposures to bystanders such as welder helpers, fire watches, or workers located adjacent to welding operations is especially important.

3.       Develop similar exposure groups (SEGs) based on the exposure assessment, and determine appropriate control measures.

Cardno ChemRisk scientists have measured and assessed workplace and environmental exposures to numerous compounds, including welding fume, and have performed historical dose reconstructions or cumulative estimates of excess cancer risk in numerous occupational settings. In addition, Cardno ChemRisk scientists have experience deriving internal occupational exposure limits based on available toxicological data. If you have any questions, or would like more information about our environmental health and safety capabilities, please contact William Cyrs, CIH, at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

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Posted by on in Centers of Excellence
Posted on behalf of Elleen Hsu

Ms. Elleen Hsu recently presented a poster entitled “Insulation Usage and Asbestos Exposures: Historical Trends and Exposure Assessment” at the 2017 International Society of Exposure Science Meeting held in Durham, North Carolina. The purpose of this research was to identify factors that impacted the trends of historical airborne asbestos concentrations from insulation products and to model how these factors would affect human exposures. The authors found that airborne fiber concentrations measured during insulation work in shipyards were 3.5 to 15.5 times higher than concentrations measured for similar tasks in non-shipyard settings. The authors also modeled asbestos exposure estimates for full-shift insulators using task-specific frequencies and concentrations reported in the literature. Using our model, a cumulative occupational exposure for an insulator could be estimated by summing the cumulative exposure for the years of interest. Additionally, our research also found that asbestos concentrations declined over time, likely driven by the passage of the OSH Act and subsequent PEL rulings, as well as advancements in asbestos research and industrial hygiene practices.
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Posted by on in Centers of Excellence
Posted on behalf of Melinda Hoang

Acrylamide is a chemical primarily used in industrial processes for its water-soluble and thickening properties, such as in the manufacturing of paper and plastic and in treating drinking water and wastewater (Lineback et al. 2012).  In 1994, the International Agency for Research on Cancer (IARC) classified acrylamide as “probably carcinogenic to humans” (IARC 1994).  Acrylamide is characterized as being neurotoxic, and its main metabolite, glycidamide, has been associated with genotoxicity.  In 2002, the Swedish National Food Administration reported the presence of high acrylamide levels in certain types of food (Tareke et al. 2002).  Acrylamide is mainly formed as part of the Maillard reaction, in which reducing sugars such as glucose and fructose react with amino acids at temperatures above 120°C in thermal food treatments such as frying, baking, and roasting (Lineback et al. 2012).  Previous studies have reported cancer as well as reproductive and developmental effects in laboratory animals exposed to acrylamide, which led California to add acrylamide to its Prop 65 list of chemicals known to the state to cause cancer or reproductive toxicity. 

Acrylamide is currently receiving widespread attention in media reports due to its formation in coffee.  Many studies have analyzed acrylamide levels in different brands and types of coffee as well as potential factors that may affect acrylamide levels in coffee, such as the coffee variety, ripeness of the coffee bean, roasting process, and storage conditions (Alves et al. 2010; Lantz et al. 2006).  However, very few studies have estimated the potential acrylamide exposure from daily intake of coffee, and even fewer studies have conducted a human health risk assessment to determine the potential cancer risk from lifetime exposure to coffee.

In 2004, the U.S. FDA published an article reporting acrylamide levels in brewed coffee; however, the agency did not estimate U.S. consumers’ total daily intake of acrylamide or calculate their potential risk from lifetime exposure based on these numbers (Andrzejewski et al. 2004).  Since then, many new coffee products and non-traditional brewing methods have entered the market and gained popularity in the U.S.  While quantitative risk assessments of traditional coffee products have been conducted for populations outside the U.S., there remain data gaps for quantifying acrylamide in key coffee products distributed within the U.S., and for understanding the risk of cancer associated with exposure to these products. 

Cardno ChemRisk has assessed human exposure to many different chemicals in consumer products.  Our exposure assessment specialists are able to estimate the exposure and characterize the potential health risks associated with acrylamide exposure via coffee consumption.  If you would like to learn more about our capabilities or have any questions about this topic, please contact Rachel Novick at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .  
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Posted by on in Centers of Excellence
Posted on behalf of Angela Perez, Paul Scott and Andrew Monnot.

The per- and polyfluoroalkyl substances, or PFASare a family of perfluorinated and polyfluorinated chemicals that have been used extensively since the 1950s in commercial applications, including surfactants, lubricants, paper and textile coatings, polishes, food packaging, and fire-fighting foams. Some of these PFAS, including perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), persist in humans and the environment, and have been detected worldwide in wildlife. 

Two senior toxicologists at Cardno ChemRisk, Drs. Angie Perez and Andy Monnot, presented research on key PFAS exposure and risk assessment issues at the 2017 International DIOXIN Symposia, held in Vancouver, Canada from August 21 -25th.  Dr. Perez presented a meta-analysis of crop uptake factors for PFAS. The objective of Dr. Perez’s research was to provide a state-of-the science review on PFAS uptake in plants intended for human and animal consumption, and to conduct a screening level human health risk assessment for consumption of PFAS based on the following: i) in which crops PFASs have been detected; ii) at what concentrations are PFASs detected; iii) which PFASs have been previously detected in crops; and iv) where in the plant PFASs tend to accumulate, if at all. Additionally, known sources of PFAS deposition in soil and anticipated source deposition trends, based on commercial use patterns, were described.


Dr. Monnot presented a poster entitled An Evaluation of Federal and State Perfluorooctanoic acid (PFOA) Drinking Water Standards in the US.  The purpose of this research was to compare the federal and state drinking water standards for PFOA in light of the recent US EPA lifetime drinking water Health Advisory for PFOA of 0.01 µg/L.  A total of 10 PFOA drinking water standards were identified, ranging from 0.014 to 1.6 µg/L.  Each state used a variety of different assumptions to derive its PFOA drinking water standards. We found that only rarely was there any attempt to evaluate background exposures to PFOA; instead, most states employed a single “default” relative source contribution (RSC) factor, which may over-estimate PFOA’s true background exposures.  

A third poster, authored by Paul K. Scott, a senior risk assessor and expert statistician at Cardno ChemRisk with over 26 years’ experience, was presented by Dr. Monnot and titled A Probabilistic Evaluation of the 2016 U.S. EPA Health Advisory for Perfluorooctanoic Acid. The purpose of this analysis was to determine if some of the factors used to derive the US EPA health advisory for PFOA resulted in an overestimation of exposure and subsequent risk.  Specifically, Scott et al. determined that the relative source contribution (RSC) factor used by the US EPA is not consistent with the information in the scientific literature on background exposures to PFOA from non-drinking water sources. In this study, alternate values for the health advisory were calculated based on more realistic assumptions for the relative source contribution (RSC).  Using alternate values for the drinking water ingestion rate and the RSC resulted in health advisories for lactating women that ranged from 0.2 to 0.76 µg/L, and for the general population that ranged from 0.3 to 1.1 µg/L.  These results suggest that the US EPA used overly conservative assumptions when deriving its health advisory.

Cardno ChemRisk scientists have conducted numerous exposure studies and human health risk assessments pertaining to PFAS. Examples of Cardno ChemRisk’s key PFAS projects include a retrospective exposure assessment for PFOA; a critical review of the findings of the C8 Health Project panel; preparation of supporting documents for Canadian Soil Quality Guidelines; preparation of estimated daily intakes of PFAS from outdoor and indoor air, dust, soil, food, drinking water, and consumer products; and a hazard evaluation and human health risk assessment for a farm after 20 years of land application of biosolids. Cardno ChemRisk scientists also regularly present on the topic of PFAS. Recently, Dr. Perez presented a webinar with Earl Hagström of Sedgwick Law in San Francisco titled Beyond PFOA and PFOS — the Next Wave of Perfluorochemicals-Related Liability”. 

If you would like to learn more about our PFAS capabilities, please contact Paul Scott at This e-mail address is being protected from spambots. You need JavaScript enabled to view it  or Angela Perez at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .  
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Posted by on in Centers of Excellence

Posted on behalf of Rachel Novick and Alison Bowman. 

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Cardno ChemRisk is a respected scientific consulting firm headquartered in San Francisco with locations and consultants across the U.S. While our website provides a formal look at our capabilities, the Cardno ChemRisk View provides an informal voice too. Various Cardno ChemRisk consultants will be sharing news and views about current trends, happenings and methodologies in the industry. We’ll also highlight activities of interest at Cardno ChemRisk, within confidentiality restrictions of course.

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