Quantitative skin exposure assessment of metals: A case study.

This article provides guidance into the quantitative risk assessment of skin exposures to metals. The use of wipe sampling methodologies has been shown to be standardised and effective for skin exposure assessment to metals. However, there is a lack of guidance documents and frameworks available to evaluate the level of health risk to workers from skin exposures to metals. Adverse health effects from exposures to metals have been described in the literature (Fernández-Nieto et al. 2006; Herman et al. 2006; Kreiss et al. 1996). Monitoring of workplace exposures typically focuses on the assessment of respiratory exposures. To provide a safe workplace there is a need to ensure all routes of exposure are risk assessed and controlled. The goal of this article was to develop skin (surface) exposure limits to metals, using the construction industry as a test environment, to quantitatively assess worker health risk of skin exposures to metals. This research concluded it was not feasible to establish single quantitative skin exposure limits to metals due to the many assumptions surrounding dermal exposures. A range of acceptable exposure limits are presented.

Lead and cadmium in infant milk and cereal based formulae marketed in Nigeria: a probabilistic non-carcinogenic human health risk assessment.

BACKGROUND: There has been concern on the likelihood of contamination of infant formulae and consequent health risk in children. OBJECTIVE: This study has assessed and compared the lead and cadmium levels in infant formulae commonly consumed in Nigeria with international regulatory limits. It has also compared the estimated daily intake with Joint FAO/WHO Expert Committee on Food Additives (JECFA) and Proposition 65 Provisional Tolerable Daily Intake. MATERIAL AND METHODS: Lead and cadmium levels in 26 different brands of infant formulae purchased from stores in Port-Harcourt, Rivers state, Nigeria in January 2018 were assayed by Atomic Absorption Spectrophotometry. RESULTS: The lead and cadmium levels in milk based infant formulae ranged from 0.61-3.50 mg/kg and 0.01-0.55 mg/kg respectively whereas the range of the lead and cadmium levels in the cereal and cereal mix based were 0.29-1.95 mg/kg and 0.02-0.37 mg/kg, and 0.47-2.34 mg/kg and 0.001-0.46 mg/kg respectively. The mean lead level in the milk-based formulae (1.49 0.89 mg/kg) was slightly higher than other groups of formulae but the difference was not significant (p<0.05). The mean level of cadmium (0.17 mg/kg) in milk-based infant formulae was higher than levels in cereal and cereal mix but there was no significant statistical difference (p<0.05) between the samples. The lead and cadmium level in milk, cereal and cereal mixed based infant formulae were above the food safe limits. CONCLUSIONS: The consumption of infant formulae may add to the body burden of cadmium and lead of children with attendant public health implication. Regular monitoring and safety assessment of metals contamination of these infant formulae is advised.

Assessment of cadmium and lead content in tomatoes and tomato products.

BACKGROUND: Cadmium and lead are completely redundant in the human body and any amount of these elements ingested poses a risk of adverse health effects. In non-occupational exposure the highest amount of xenobiotics enters the body with food. Valued for their taste, universal culinary application and health benefits tomatoes and tomato products are consumed almost every day by a large proportion of society. In order to protect consumers' health it is very important to monitor cadmium and lead content in food products. OBJECTIVE: The aim of the study was the health assessment of cadmium and lead content in tomatoes and tomato products in relation to their acceptable maximum levels in the relevant legislation. MATERIAL AND METHODS: Fresh fruits of the tomato plant and tomato products (juices, purées, concentrates, sauces) were analysed. Heavy metal content (Cd, Pb) was determined by flameless atomic absorption spectrometry (AAS). Before the AAS determination the samples were subjected to pressure mineralisation using microwave energy. RESULTS: Cadmium and lead contents in the studied food products were within the allowed range (the maximum level of cadmium and lead contamination of tomatoes is 0.05 mg/kg and 0.1 mg/kg of fresh mass). The limit for cadmium was exceeded only in a canned tomato concentrate (0.064 mg/kg of fresh mass). The average cadmium content in raw tomatoes and tomato products was: 0.017 mg/kg fresh weight, and lead 0.021 mg/kg fresh weight. CONCLUSIONS: Despite the low cadmium and lead contamination of the study samples of tomatoes and tomato products, it seems desirable to constantly monitor the content of these elements in food due to their ability to accumulate in the body and the risk of adverse health effects developing after many years of exposure, even to small doses.

Derivation of an occupational exposure limit for benzene using epidemiological study quality assessment tools.

This paper derives an occupational exposure limit for benzene using quality assessed data. Seventy-seven genotoxicity and 36 haematotoxicity studies in workers were scored for study quality with an adapted tool based on that of Vlaanderen et al., 2008 (Environ Health. Perspect. 116 1700-5). These endpoints were selected as they are the most sensitive and relevant to the proposed mode of action (MOA) and protecting against these will protect against benzene carcinogenicity. Lowest and No- Adverse Effect Concentrations (LOAECs and NOAECs) were derived from the highest quality studies (i.e. those ranked in the top tertile or top half) and further assessed as being "more certain" or "less certain". Several sensitivity analyses were conducted to assess whether alternative "high quality" constructs affected conclusions. The lowest haematotoxicity LOAECs showed effects near 2 ppm (8 h TWA), and no effects at 0.59 ppm. For genotoxicity, studies also showed effects near 2 ppm and showed no effects at about 0.69 ppm. Several sensitivity analyses supported these observations. These data define a benzene LOAEC of 2 ppm (8 h TWA) and a NOAEC of 0.5 ppm (8 h TWA). Allowing for possible subclinical effects in bone marrow not apparent in studies of peripheral blood endpoints, an OEL of 0.25 ppm (8 h TWA) is proposed.

Human pharmaceutical and pesticide residues in Israeli dairy milk in association with dietary risk assessment.

Throughout the world, more than six billion people consume milk and milk products yearly. The safety and quality of dairy milk are regularly monitored in most countries worldwide. The Israeli monitoring program of chemical residues in milk has not changed in the last decades, focusing only on major veterinary drugs and few selected environmental contaminants such as heavy metals and persistent organic pollutants. Consequently, a knowledge gap exists regarding the potential occurrence of other chemicals such as human pharmaceuticals and non-monitored pesticides in milk. In this survey, 51 commercial bovine and goat milk samples were analysed by LC-MS/MS and pharmaceutical and pesticide residues are reported in the range of 0.1-93 µg/L. Israeli milk samples revealed at least one and up to five chemical residues simultaneously. The pesticides found in milk were below the European maximum residue limit values. The risk assessment performed, indicated negligible risk.

Multi-Mycotoxin Occurrence and Exposure Assessment Approach in Foodstuffs from Algeria.

A survey on 120 cereal samples (barley, maize, rice and wheat) from Algerian markets has been carried out to evaluate the presence of 15 mycotoxins (ochratoxin A, deoxynivalenol, fumonisin B1 and B2, T-2 and HT-2 toxins, zearalenone, fusarenon X, citrinin, sterigmatocystin, enniatins A, A1, B and B1, and beauvericin). With this purpose, a QuEChERS-based extraction and ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) were used. Analytical results showed that 78 cereal samples (65%) were contaminated with at least one toxin, while 50% were contaminated with three to nine mycotoxins. T-2 toxin, citrinin, beauvericin and deoxynivalenol were the most commonly found mycotoxins (frequency of 50%, 41.6%, 40.8% and 33.3%, respectively). Fumonisins (B1 + B2), enniatins B and B1, deoxynivalenol and zearalenone registered high concentrations (289-48878 µg/kg, 1.2-5288 µg/kg, 15-4569 µg/kg, 48-2055 µg/kg and 10.4-579 µg/kg, respectively). Furthermore, concentrations higher than those allowed by the European Union (EU) were observed in 21, 8 and 1 samples for fumonisins, zearalenone and deoxinivalenol, respectively. As a conclusion, the high levels of fumonisins (B1 + B2) in maize and deoxynivalenol, zearalenone and HT-2 + T-2 toxins in wheat, represent a health risk for the average adult consumer in Algeria. These results pointed out the necessity of a consistent control and the definition of maximum allowed levels for mycotoxins in Algerian foodstuffs.

Will worker DNELs derived under the European REACH regulation extend the landscape of occupational exposure guidance values?

Derived no-effect levels for workers (wDNELs) under the European REACH legislation have many aspects in common with occupational exposure limits (OELs). In an attempt to examine under which circumstances wDNELs might be used as exposure guidance outside their intended application, we compared derivation methods, coverage of substances and numerical values of wDNELs against two regulatory OEL lists (European Commission and Sweden) and three sets of recommendations (European SCOEL, German MAK and US ACGIH). Finally, we looked closer at wDNELs where SCOEL concluded that data were insufficient to derive an OEL. Major differences between wDNELs and OELs include regulatory background, intended use, actors involved, substance selection criteria, transparency and procedure of derivation, and operationalisation in terms of risk management measures. As of summer 2018, approximately five times more substances were covered by wDNELs than by the five sets of OELs examined herein. Meanwhile, many occupationally relevant pollutants were not covered by wDNELs, e.g. one-third of Swedish OELs lack corresponding wDNELs. We also note that wDNELs and OELs for the same substance may vary considerably, up to several orders of magnitude. In conclusion, with extensive substance coverage, wDNELs extend the landscape beyond the OELs. That said, important limitations are (1) that many air pollutants relevant for workers' health are not covered by REACH, and (2) concerns for inconsistencies in the derivation of wDNELs and in their level of protection. In particular, that route-to-route extrapolation is a common practice that may be grossly misleading when the effect of concern is local, e.g. sensitisation.

Ochratoxin A in the Portuguese Wine Market, Occurrence and Risk Assessment.

Ochratoxin A (OTA) is mainly found in cereals and cereal-based foodstuffs, but also in wine. Being one of the most consumed alcoholic drinks in Portugal and one of the main sources of human exposure to OTA, wine monitoring and exposure studies are essential. The analytical methodology consisted of the direct injection of the filtered samples into the liquid chromatograph, equipped with fluorescent detection (LC-FLD). Linearity was adequate, both in mobile phase and in matrix-matched solutions, with R2 values higher than 0.997. The limits of detection were 0.08 and 0.39 µg/L for white and red wine, respectively and recoveries were above 91.9%. One hundred wine samples acquired on the Portuguese market were investigated. In 5 samples the OTA was detected, with the red wine presenting higher frequency of contamination. Regarding the risk to human health it was observed that the estimated weekly intake (EWI) is considerably lower than the established tolerable weekly intake (TWI).

Pesticide residues in Lebanese apples and health risk assessment.

In Lebanon, apples are among the most consumed commodities; however, pesticide residues in apples have not been evaluated so far. Therefore, this study presents the occurrence of pesticide residues in apples produced in Lebanon during 2012-2016. A total of 212 samples were analysed for the presence of pesticides using the QuEChERS multi-residue extraction method, followed by GC-MS. Pesticide residues were not observed in 23% of the samples. Whereas pesticide residues were found in 77% of the samples, among them 61% exceeded the maximum residue limits (MRL) and 16% contained residues below the MRL. The most frequently detected pesticide residues were chlorpyrifos (n = 142), methidathion (n = 34), cypermethrin (n = 21), lambda-cyhalothrin (n = 16), myclobutanil (n = 13) and diazinon (n = 9). A preliminary long-term exposure assessment for the detected pesticides in apples showed that Hazard Quotient (HQ) was in the range of 0.1-8% of the ADI's, indicating no risk to human health.

Occurrence of Aflatoxin M1 in raw and processed milk and assessment of daily intake in Lahore, Multan cities of Pakistan.

In this survey aflatoxin, M1 was quantified in raw and processed milk from various areas of two big cities of Punjab province, i.e. Lahore and Multan. The results indicated that approximately 90% of the raw milk samples collected from Lahore city was contaminated with aflatoxin M1. Similarly, around 92% of the raw milk samples collected from Multan city was contaminated with aflatoxin M1. All samples of processed milk and tea whiteners were contaminated and 56% of the contaminated processed milk samples and 66% of the contaminated tea whitener samples were violating the maximum limits. The dietary exposure data of AFM1 among six different groups was calculated, which indicated that the male children population was the most vulnerable group to AFM1, up to 6.68 ng L-1 per day and the least affected one was the female group above 20 years of age with 1.13 ng L-1 per day.

Mercury and cadmium in swordfish and yellowfin tuna and health risk assessment for Sri Lankan consumers.

Commercially important marine fish, yellowfin tuna (YFT), and swordfish (SF), collected from the Indian Ocean around Sri Lanka were analysed for mercury (Hg) and cadmium (Cd) content. The ranges for Hg were < 0.07-1.60 and < 0.07-4.30 mg/kg, while for Cd < 0.006-0.134 and 0.006-0.180 mg/kg in YFT and SF, respectively. In SF 13.3% and in YFT 9.2% exceeded the 1 mg/kg limit for Hg, while 3.1% of YFT exceeded the 0.1 mg/kg limit for Cd. All other samples were well below the maximum limits. Human health risk assessment was investigated using Estimated Daily Intake, Total Hazard Quotient, Hazard Index, and Provisional Tolerable Weekly Intake values for Hg and Cd. The data indicated that the current YFT and SF consumption pattern in Sri Lanka poses no threat to consumer's health. However, further research and awareness on food safety aspects is needed on specific groups such as children and for areas in which consumption of seafood is high.

Occurrence and dietary exposure assessment of multiple mycotoxins in corn-based food products from Shandong, China.

This study was designed to investigate the occurrence and exposure assessment of multiple mycotoxins in corn-based food products from Shandong Province, China. Results demonstrated that the mean level of total mycotoxins in test samples was 197.2 µg/kg. The most frequently found mycotoxins were deoxynivalenol (96.7%) and fumonisin B1 (94.4%), with mean contamination levels of 65.24 and 128.2, respectively. Among these corn-based food products, thin corn pancake had the highest mean contamination (886.7 µg/kg), followed by wotou (143.7 µg/kg), corn cake (135.4 µg/kg) and mantou (63.73 µg/kg). The average exposure values to total fumonisins and deoxynivalenol were 0.05 and 0.02 µg/kg bw/day, which were lower than the provisional maximum tolerable daily intake values of 2 and 1 µg/kg bw/day, respectively, as established by the Joint FAO/WHO Expert Committee on Food Additives. In the future strict control and systematic monitoring are needed to secure food safety and human health.

[Assessment of chemical pollutant levels of dietary salt in Shanghai in 2015].

OBJECTIVE: To detect the chemical pollutants concentrations of dietary salt and to comprehend the effect of chemical pollutants on the quality of salt. METHODS: 45 kinds of salt with different countries, brands and types were collected in Shanghai during May to June in 2015. Five different heavy metal elements, fluoride, potassium ferrocyanide and 16 phthalate plasticizers were measured, and the result were analyzed with the standard. RESULTS: The salt of largest consumption was domestic halite/well salt in Shanghai, accounting for 87. 6% of the total salt consumption. Lead was detected in only two types of salt at concentrations recorded of 0. 047 and 0. 077 mg/kg, which were far below the Chinese national standard. The concentrations of total arsenic, total mercury, cadmium, and barium were lower than the limit of detection( LOD) in all samples. The median fluoride concentration of salts was 0. 16 mg/kg( maximum 2. 50 mg/kg). The median fluoride concentration of domestic salts was significantly lower than foreign-produced salts( P < 0. 05), and it was significantly higher in sea salt than in other types of salt. The median potassium ferrocyanide concentration in 12 types of salts was4. 30 mg/kg( maximum 9. 2 mg/kg), which was lower than the Chinese national standard. Just 3 salt types had low levels of bis( 2-ethylhexyl) phthalate concentrations that were above the LOD, at 0. 208, 0. 375 and 0. 380 mg/kg, respectively. CONCLUSION: The level of chemical pollutants in salt is either very low or absent.

The vexed question of whether or not to measure levels of direct oral anticoagulants before surgery or invasive procedures.

Direct oral anticoagulants (DOAC) possess high bioavailability, and their anticoagulant effect is more predictable than that of vitamin K antagonists, hence they do not require routine dose adjustment based on laboratory testing. However, there are circumstances when laboratory testing may be useful, including patients who need to undergo surgery or invasive procedures. Most guidelines state that patients on DOAC may safely undergo surgery/invasive procedures by stopping anticoagulation for a few days before intervention without testing if renal function is within normal limits. This review article discusses the pros and cons of measuring (or not measuring) DOAC levels before surgery/invasive procedures by a multidisciplinary team of experts with different background, including the thrombosis laboratory, clinical thrombosis, internal medicine, cardiology and nephrology. The conclusion is that measuring DOAC with dedicated tests before surgical or invasive procedures is important for patient safety. It provides the best and most direct evidence to rule in (or to rule out) clinically relevant concentrations of residual drugs. Regulatory agencies should urgently approve their use in clinical practice. Hospital administrators should make them available, and clinical laboratories should set up the relative methods and make them available to clinicians.

Risk assessment of genotoxic and carcinogenic alkenylbenzenes in botanical containing products present on the Chinese market.

In the present study, a risk assessment of plant food supplements (PFS), traditional Chinese medicines (TCM) and herbal teas containing alkenylbenzenes was performed using the Margin of Exposure (MOE) approach. The levels of alkenylbenzenes in botanical preparations collected on the Chinese market were quantified and the combined estimated daily intake (EDI) was determined using dose additivity. The combined EDI values obtained assuming equal potency of all alkenylbenzenes detected in the PFS, TCM and herbal teas were 0.3 to 14.3, 0.05 to 539.4 and 0.04 to 42.5 µg/kg bw/day, respectively. Calculating combined EDI values taking into account the toxic equivalency (TEQ) approach, the values for PFS, TCM and herbal teas were 0.3 to 7.7, 0.05 to 278.0 and 0.02 to 16.5 µg estragole equivalents/kg bw/day, respectively. The MOE values resulting from consumption of these PFS, TCM and one cup of herbal tea per day during life-time were generally lower than 10 000, suggesting a potential priority for risk management. For short-term exposure such as two weeks consumption, applying Haber's rule, only one TCM 6 () still had an MOE value below 10 000. It is concluded that selected consumption of Chinese botanical preparations raise a concern because of exposure to alkenylbenzenes, especially when exposure is for longer periods of time.

PAHs in seafood from the Mediterranean Sea: An exposure risk assessment.

Seafood represent an important food source for human, and seafood quality is associated with marine environment quality. PAHs are one of the main organic environmental contaminants and they can be introduced into the body through different way (ingestion, inhalation, dermal absorption). We present data on bioaccumulation of the sixteen PAHs, defined priority by the U.S.- EPA, in Sardina pilchardus, Solea solea and Donax trunculus, three species caught in the Catania Gulf and highly consumed by the local population. The risk to develop chronic systemic and carcinogenic effects due to the consumption of these target species was evaluated through the EDI, THQ and CR. EDI derived from D. trunculus ingestion falls within the range calculated by the EFSA. The THQ is less than 1, and the CR calculated for the Benzo(a)Pyrene is at the limit of the ARL (1✕10-5). EDI derived from S. pilchardus and S. solea ingestion are below the range calculated by the EFSA. The THQ is less than 1, and the CR is below the acceptable risk level. The contamination level found in local seafood determines a low risk to develop chronic systemic effects, but the cancer risk could be of health concern especially for high-frequency molluscs consumers.

Analysis and Assessment of Exposure to Selected Phthalates Found in Children's Toys in Christchurch, New Zealand.

Internationally several phthalates are subject to regulatory control regarding maximum allowable concentrations in children's toys. Such regulation is not in place in New Zealand. Phthalates have been associated with developmental toxicity and endocrine disruption. We determined the concentration of seven phthalates in children's toys purchased in Christchurch, New Zealand. These results provided data for an exposure assessment deriving Hazard Indices (HI) for oral and dermal exposure routes in children, based on the concentration of mixtures of phthalates shown by the EU to produce either reproductive/developmental or hepatotoxic effects. Of the 49 toys analyzed, 65% contained at least one phthalate at a concentration of >0.1% by mass; and 35% contained multiple-phthalates at individual concentrations of >0.1%. A HI of 3.4 was derived for the combined exposures to the four phthalates associated with reproductive and developmental effects. A HI of 0.3 was derived for the group of phthalates associated with hepatotoxic effects. Five phthalates were detected at levels exceeding the EU regulatory limit of 0.1% by mass. Risk assessment calculations indicate that, using realistic exposure scenarios, the worst-case combined exposure to phthalates associated with developmental toxicity exceeded a HI of 1 so may cause adverse developmental effects.

Edible wild plants growing in contaminated floodplains: implications for the issuance of tribal consumption advisories within the Grand Lake watershed of northeastern Oklahoma, USA.

Metal releases from the Tri-State Mining District (TSMD) that is located in southwestern Missouri, southeastern Kansas, and northeastern Oklahoma, have contaminated floodplain soils within the Neosho and Spring river watersheds of the Grand Lake watershed. Since the Oklahoma portion of the watershed lies within ten tribal jurisdictions, the potential accumulation of metals within plant species that are gathered and consumed by tribal members, as well as the resulting metal exposure risks to tribal human health, was a warranted concern for further investigation. Within this study, a total of 36 plant species that are commonly consumed by tribes were collected from floodplain areas that were previously demonstrated to have elevated soil metal concentrations relative to reference sites. A significant, positive correlation was shown for metal concentrations in plant tissues versus soil (n = 258; Cd: R = 0.72, p = 0.00; Pb: R = 0.52, p = 0.00; and Zn: R = 0.70, p = 0.00). Additionally, a significant difference in metal concentration distributions existed between reference and impacted plant samples (n = 210, p = 0.00 for all metals). These results proved that floodplain soils are a major contamination pathway for metal accumulation within plants, and the source of metal contamination is the result of mining releases from the TSMD. Metal accumulation within plants was found to vary according to specific metal and plant species. The lowest dietary exposure out of all plant organs sampled were associated with fruit, whereas the highest was associated with roots, stem/leaves, and low-lying leafy greens. Metals in plants were compared to weekly dietary intake limits established by the Joint FAO/WHO Expert Committee on Food Additives. Based on specific serving sizes established within this study for tribal children and adults, many plant species had sufficient concentrations to warrant tribal consumption restrictions within the floodplains of Elm Creek, Grand Lake, Lost Creek, Spring River, and Tar Creek. Importantly, these results highlighted the necessity for the issuance of plant consumption advisories for tribal communities in the watershed. A consumption restriction guide on the number of allowable servings of each species per week at specific streams was developed within this study for tribal children and adults. Results also demonstrated that soil metal concentrations do not need to be exceptionally elevated relative to reference sites in order for plants to accumulate sufficient metal concentrations to exceed dietary limits for one serving. Therefore, the exposure risk associated with the consumption of plants cannot be accurately predicted solely from metal concentrations within soils, but must be based on metal concentrations within specific plant tissues on a site-by-site basis. A weekly consumption scenario was created within this study in order to better understand the potential metal dietary exposures to child and adult tribal members who consume multiple servings of multiple plant species per day, as well as benthic invertebrates and fish from the watershed. These findings demonstrated that plants pose a greater consumption exposure risk for tribal members than benthic invertebrates or fish. Therefore, without the consideration of exposure risks associated with the consumption of plants within future human health risk assessments, tribal health risks will be severely underestimated.

Carcinogenicity of multi-walled carbon nanotubes: challenging issue on hazard assessment.

OBJECTIVES: This report reviews the carcinogenicity of multi-walled carbon nanotubes (MWCNTs) in experimental animals, concentrating on MWNT-7, a straight fibrous MWCNT. METHODS: MWCNTs were administered to mice and rats by intraperitoneal injection, intrascrotal injection, subcutaneous injection, intratracheal instillation and inhalation. RESULTS: Intraperitoneal injection of MWNT-7 induced peritoneal mesothelioma in mice and rats. Intrascrotal injection induced peritoneal mesothelioma in rats. Intratracheal instillation of MWCNT-N (another straight fibrous MWCNT) induced both lung carcinoma and pleural mesothelioma in rats. In the whole body inhalation studies, in mice MWNT-7 promoted methylcholanthrene-initiated lung carcinogenesis. In rats, inhalation of MWNT-7 induced lung carcinoma and lung burdens of MWNT-7 increased with increasing concentration of airborne MWNT-7 and increasing duration of exposure. CONCLUSIONS: Straight, fibrous MWCNTs exerted carcinogenicity in experimental animals. Phagocytosis of MWCNT fibers by macrophages was very likely to be a principle factor in MWCNT lung carcinogenesis. Using no-observed-adverse-effect level-based approach, we calculated that the occupational exposure limit (OEL) of MWNT-7 for cancer protection is 0.15 µg/m3 for a human worker. Further studies on the effects of the shape and size of MWCNT fibers and mode of action on the carcinogenicity are required.

Standards for arsenic in drinking water: Implications for policy in Mexico.

Global concern about arsenic in drinking water and its link to numerous diseases make translation of evidence-based research into national policy a priority. Delays in establishing a maximum contaminant level (MCL) to preserve health have increased the burden of disease and caused substantial and avoidable loss of life. The current Mexican MCL for arsenic in drinking water is 25 µg/l (2.5 times higher than the World Health Organization (WHO) recommendation from 1993). Mexico's struggles to set its arsenic MCL offer a compelling example of shortcomings in environmental health policy. We explore factors that might facilitate policy change in Mexico: scientific evidence, risk communication and public access to information, economic and technological resources, and politics. To raise awareness of the health, societal, and economic implications of arsenic contamination of drinking water in Mexico, we suggest action steps for attaining environmental policy change and better protect population health.