Arsenic Concentrations in Ground and Surface Waters across Arizona Including Native Lands

Arsenic Impairs Wound Healing Processes in Dermal Fibroblasts and Mice

Inorganic arsenic (NaAsO2) is a naturally occurring metalloid found in water resources globally and in the United States at concentrations exceeding the U.S. Environmental Protection Agency Maximum Contamination Level of 10 ppb. While exposure to arsenic has been linked to cancer, cardiovascular disease, and skin lesions, the impact of arsenic exposure on wound healing is not fully understood. Cultured dermal fibroblasts exposed to NaAsO2 displayed reduced migration (scratch closure), proliferation, and viability with a lowest observable effect level (LOEL) of 10 µM NaAsO2 following 24 h exposure. An enrichment of Matrix Metalloproteinase 1 (MMP1) transcripts was observed at a LOEL of 1 µM NaAsO2 and 24 h exposure. In vivo, C57BL/6 mice were exposed to 10 µM NaAsO2 in their drinking water for eight weeks, then subjected to two full thickness dorsal wounds. Wounds were evaluated for closure after 6 days. Female mice displayed a significant reduction in wound closure and higher erythema levels, while males showed no effects. Gene expression analysis from skin excised from the wound site revealed significant enrichment in Arsenic 3-Methyltransferase (As3mt) and Estrogen Receptor 2 (Esr2) mRNA in the skin of female mice. These results indicate that arsenic at environmentally relevant concentrations may negatively impact wound healing processes in a sex-specific manner.

Worldwide Surveillance Actions and Initiatives of Drinking Water Quality: A Scoping Review

This study identified and mapped worldwide surveillance actions and initiatives of drinking water quality implemented by government agencies and public health services. The scoping review was conducted between July 2021 and August 2022 based on the Joanna Briggs Institute method. The search was performed in relevant databases and gray literature; 49 studies were retrieved. Quantitative variables were presented as absolute and relative frequencies, while qualitative variables were analyzed using the IRaMuTeQ software. The actions developed worldwide and their impacts and results generated four thematic classes: (1) assessment of coverage, accessibility, quantity, and drinking water quality in routine and emergency situations; (2) analysis of physical-chemical and microbiological parameters in public supply networks or alternative water supply solutions; (3) identification of household water contamination, communication, and education with the community; (4) and investigation of water-borne disease outbreaks. Preliminary results were shared with stakeholders to favor knowledge dissemination.

Environmentally relevant arsenic exposure affects morphological and molecular endpoints associated with reproduction in the Western mosquitofish, Gambusia affinis

Arsenic (As) exposure, even at low environmentally relevant levels, may cause detrimental health outcomes through developmental toxicity and by acting as an endocrine disrupting compound (EDC). Although several studies indicate that wildlife bioaccumulate As, few evaluate the health impact on fish species in their natural environment. In the U.S., As has a drinking water regulatory limit of 10 μg/L. In many parts of Arizona, surface water and groundwater have naturally elevated levels of As from geologic deposits and contamination is exacerbated by anthropogenic activity. In aquatic environments, the Western mosquitofish, Gambusia affinis, is a good bioindicator for EDC exposure because of the distinct androgen-related development of an intromittent organ, the gonapodium, in males. We evaluated morphological and reproductive outcomes in mosquitofish exposed to As. In a laboratory experiment, juvenile male mosquitofish were exposed to sodium arsenite (0 μg/L, 0.75 μg/L, 7.50 μg/L, and 75 μg/L) for 30 days, and in a field study, populations of adult male mosquitofish were collected in Arizona waterways with As levels above and below the World Health Organization's regulatory limit. In both studies, higher As exposure was significantly associated with altered hepatosomatic indices, altered fish morphology, shortened gonopodia, and lower gonopodia-somatic indices. In the field experiment, populations from surface water with higher As concentrations exhibited lower condition factors, lower gonadal-somatic indices, distinct gonopodia shapes, and altered estrogen receptor alpha and vitellogenin gene expression; androgen receptor expression was unchanged. Together, laboratory and field results suggest that As exposure at environmentally-relevant levels affects general growth and reproductive development in mosquitofish. Observed effects may further influence individual health, mobility, or reproductive function, and because G. affinis is a species known to tolerate and adapt to a wide range of environments, it serves as a local bioindicator species as well as a model organism for parallel field and laboratory studies.

Synonymous single nucleotide polymorphism in arsenic (+3) methyltransferase of the Western mosquitofish (Gambusia affinis) and its gene expression among field populations

Naturally occurring arsenic is toxic at extremely low concentrations, yet some species persist even in high arsenic environments. We wanted to test if these species show evidence of evolution associated with arsenic exposure. To do this, we compared allelic variation across 872 coding nucleotides of arsenic (+3) methyltransferase (as3mt) and whole fish as3mt gene expression from three field populations of Gambusia affinis, from water sources containing low (1.9 ppb), medium-low (3.3 ppb), and high (15.7 ppb) levels of arsenic. The high arsenic site exceeds the US EPA's Maximum Contamination Level for drinking water. Medium-low and high populations exhibited homozygosity, and no sequence variation across all animals sampled. Eleven of 24 fish examined (45.8%) in the low arsenic population harbored synonymous single nucleotide polymorphisms (SNPs) in exons 4 and/or 10. SNP presence in the low arsenic population was not associated with differences in as3mt transcript levels compared to fish from the medium-low site, where SNPs were noted; however, as3mt expression in fish from the high arsenic concentration site was significantly lower than the other two sites. Low sequence variation in fish populations from sites with medium-low and high arsenic concentrations suggests greater selective pressure on this allele, while higher variation in the low population suggests a relaxed selection. Our results suggest gene regulation associated with arsenic detoxification may play a more crucial role in influencing responses to arsenic than polymorphic gene sequence. Understanding microevolutionary processes to various contaminants require the evaluation of multiple populations across a wide range of pollution exposures.

Our Relationship to Water and Experience of Water Insecurity among Apsáalooke (Crow Indian) People, Montana

Affordable access to safe drinking water is essential to community health, yet there is limited understanding of water insecurity among Native Americans. Therefore, the focus of this paper is to describe Apsáalooke (Crow Indian) tribal members' experiences with water insecurity. For Apsáalooke people, local rivers and springs are still vitally important for traditional cultural activities. We interviewed 30 Native American adults living on the Crow Reservation in Southeastern Montana. Participants answered six open-ended interview questions about their water access, costs of obtaining water and changes in their domestic and traditional water uses. Participants emphasized how the use of water has changed over time and described the complex challenges associated with addressing water insecurity in their community, including the importance of considering the spiritual and cultural impacts of water insecurity on health. Water insecurity is a growing global problem and more attention and efforts are needed to find appropriate and affordable solutions.

Exposure to uranium and co-occurring metals among pregnant Navajo women

Navajo Nation residents are at risk for exposure to uranium and other co-occurring metals found in abandoned mine waste. The Navajo Birth Cohort Study (NBCS) was initiated in 2010 to address community concerns regarding the impact of chronic environmental exposure to metals on pregnancy and birth outcomes. The objectives of this paper were to 1) evaluate maternal urine concentrations of key metals at enrollment and delivery from a pregnancy cohort; and 2) compare the NBCS to the US general population by comparing representative summary statistical values. Pregnant Navajo women (N = 783, age range 14-45 years) were recruited from hospital facilities on the Navajo Nation during prenatal visits and urine samples were collected by trained staff in pre-screened containers. The U.S. Centers for Disease Control and Prevention (CDC), National Center for Environmental Health's (NCEH) Division of Laboratory Sciences (DLS) analyzed urine samples for metals. Creatinine-corrected urine concentrations of cadmium decreased between enrollment (1st or 2nd trimester) and delivery (3rd trimester) while urine uranium concentrations were not observed to change. Median and 95th percentile values of maternal NBCS urine concentrations of uranium, manganese, cadmium, and lead exceeded respective percentiles for National Health and Nutrition Evaluation Survey (NHANES) percentiles for women (ages 14-45 either pregnant or not pregnant.) Median NBCS maternal urine uranium concentrations were 2.67 (enrollment) and 2.8 (delivery) times greater than the NHANES median concentration, indicating that pregnant Navajo women are exposed to metal mixtures and have higher uranium exposure compared to NHANES data for women. This demonstrates support for community concerns about uranium exposure and suggests a need for additional analyses to evaluate the impact of maternal metal mixtures exposure on birth outcomes.

Arsenic Concentrations in Ground and Surface Waters across Arizona Including Native Lands

Parts of the Southwestern United States report arsenic levels in water resources that are above the United States Environmental Protection Agency's current drinking water limits. Prolonged exposure to arsenic through food and drinking water can contribute to significant health problems including cancer, developmental effects, cardiovascular disease, neurotoxicity, and diabetes. In order to understand exposure risks, water sampling and testing has been conducted throughout Arizona. This information is available to the public through often non-overlapping databases that are difficult to access and in impracticable formats. The current study utilized a systemic compilation of online databases to compile a spreadsheet containing over 33,000 water samples. The reported arsenic concentrations from these databases were collected from 1990-2017. Using ArcGIS software, these data were converted into a map shapefile and overlaid onto a map of Arizona. This visual representation shows that arsenic levels in surface and ground water exceed the United States Environmental Protection Agency's drinking water limits for many sites in several counties in Arizona, and there is an underrepresentation of sampling in several tribal jurisdictions. This information is useful for water managers and private well owners throughout the State for determining safe drinking water sources and limiting exposure to arsenic.