Since 2011, tourism to Mexico’s Yucatán Peninsula has been heavily impacted by large masses of sargassum seaweed washing up on the beaches, with the largest seaweed event occurring in 2019. Seaweed deters beach tourism, potentially shifting tourism inland towards other activities such as swimming in cenotes (sinkholes). Our mixed methods study combined data from surveys of visitors to the region, interviews with tourists and tour operators, thematic analysis of newspaper articles, laws and policies and analysis of water samples from a cenote to understand the environmental impact on cenotes of this shifting tourism industry. We identified intentional efforts by the tourism industry to encourage cenote tourism in response to the seaweed problem, and our survey and interview data confirmed that tourists are choosing to visit cenotes in lieu of beaches. Water samples from one tourist cenote in 2019 indicated increased pollution relative to previous years. Current regulations and management of tourist cenotes are weak, creating the potential for significant long term harm to the environment and to the water sovereignty of surrounding communities. Regulation of cenotes should be strengthened to protect these fragile karst ecosystems and to give local and indigenous residents a formal voice in the management process.

The Mexican Caribbean is part of the Mesoamerican Barrier Reef System, considered the second largest reef system globally. This system, as well as inland aquatic ecosystems, are at risk of contamination due to the intensive use of sunscreen by the tourists who visit the Riviera Maya each year. At present, the regulation and management of sunscreens are inconsistent, with most policies and legislation focused on the protected marine areas with little current focus on inland aquatic ecosystems. An estimated 229.76 tons of sunscreen are used annually, with residues putting the health of the marine and freshwater aquatic ecosystems and residents at risk. Groundwater is used recreationally (e.g., tourists swimming in sinkholes or cenotes) and as household drinking water. To understand the environmental impacts of sunscreen use and the management implications, a mixed-methods study was carried out, combining survey and interview data on how tourists use sunscreen and their perceptions of discharge of sunscreens into the water, with analysis of regional, national and international policies and legislation. Our findings of touristic behaviors, gaps in current legislation, and the pollution implications of different sunscreen types provide useful information for future decision-making and the creation of stronger environmental regulations.

The Yalahau region, located in the northeastern portion of the Yucatán Peninsula, hosts a series of elongated depressions trending north/south in the direction of Isla Holbox, identified as the Holbox Fracture Zone. Previous studies have explored the geomorphology and various hydrologic characteristics of the Yucatán Peninsula; however, there is a paucity of data concerning the interior region where the fractures are located. Strontium isotope ratios and major ion geochemistry data of the surface water and groundwater of this region serve as a hydrogeochemical fingerprint, aiding in constraining the hydrological boundaries, determining flow paths, and characterizing hydrogeochemical processes that impact the composition of the groundwater within the region. ⁸⁷Sr/⁸⁶Sr isotope ratios indicate a different signature than the surrounding bedrock Sr ratio, suggesting that the flow throughout the Yalahau region is moving through channels faster than that of much of the Yucatán. Through major ion geochemistry and ⁸⁷Sr/⁸⁶Sr isotope ratios, we were able to delineate at least two flow paths within the Yalahau region and identify a point of saline intrusion at least 35 km from the coast. Gaining an understanding of the hydrogeochemistry and water flow regions is crucial in determining the impact of various activities (e.g., extensive tourism, drinking water withdrawal, wastewater discharge/injection) that occur within the Yucatán Peninsula.

Mandalay is a major city in central Myanmar with a high urban population and which lacks a central wastewater management system, a solid waste disposal process, and access to treated drinking water. The purpose of this study is to investigate the groundwater quality of local dug wells and tube wells, determine quantitative data on characteristics of the Amarapura Aquifer, and compare seasonal variations in groundwater flow and quality. Water samples were collected during the dry and wet seasons, then analyzed for major ion chemistry using ion chromatography to identify indicators of wastewater contamination transport to the shallow aquifer and to compare seasonal variations in groundwater chemistry. An open-source analytic element model, GFLOW, was used to describe the physical hydrogeology and to determine groundwater flow characteristics in the aquifer. Hydrogeochemistry data and numerical groundwater flow models provide evidence that the Amarapura Aquifer is susceptible to contamination from anthropogenic sources. The dominant water types in most dug wells and tube wells is Na-Cl, but there is no known geologic source of NaCl near Mandalay. Many of these wells also contain water with high electrical conductivity, chloride, nitrate, ammonium, and E. coli. Physical measurements and GFLOW characterize groundwater flow directions predominantly towards the Irrawaddy River and with average linear velocities ranging from 1.76 × 10⁻² m/day (2.04 × 10⁻⁷ m/s) to 9.25 m/day (1.07 × 10⁻⁴ m/s). This is the first hydrogeological characterization conducted in Myanmar. Mandalay est une ville d’importance majeure du Myanmar central avec une forte population urbaine, avec une absence de système central de gestion des eaux usées, des déchets solides, et d’un accès à une eau de boisson traitée. Le propos de la présente étude est d’examiner la qualité de l’eau de puits artisanaux et de forages, de définir les données quantitatives relatives aux caractéristiques de l’Aquifère d’Amarapura, et de comparer les variations saisonnières de l’écoulement des eaux souterraines et de leur qualité. Des échantillons d’eau ont été prélevés pendant la saison sèche et la saison humide, puis analysés avec une chimie des ions majeurs en utilisant la chromatographie ionique, afin d’identifier les indicateurs d’un transport de pollution des eaux usées vers l’aquifère superficiel et de comparer les variations saisonnières de la chimie des eaux souterraines. Un modèle à élément analytique, GFLOW, code en accès libre, a été utilisé pour décrire l’hydrogéologie physique et déterminer les caractéristiques de l’écoulement des eaux souterraines dans l’aquifère. Les données hydrogéochimiques et les modèles numériques d’écoulement des eaux souterraines montrent à l’évidence que l’Aquifère d’Amarapura est vulnérable à une contamination d’origine anthropique. Le type d’eau dominant dans la plupart des puits artisanaux et des forages est le type Na-Cl, mais il n’y a pas d’origine géologique connue de NaCl à proximité de Mandalay. Beaucoup de ces puits contiennent également une eau à conductivité électrique élevée, avec chlorures, nitrates, ammonium et E. coli. Les mesures physiques et GFLOW font apparaître des directions d’écoulement privilégiées vers le fleuve Irrawaddy, avec des vitesses linéaires moyennes comprises entre 1.76 × 10^–2 m/jour (2.04 × 10^–7 m/s) et 9.25 m/jour (1.07 × 10^–4 m/s). Cette étude est la première caractérisation hydrogéologique conduite au Myanmar. Mandalay es una ciudad importante en el centro de Myanmar con una alta población urbana y que carece de un sistema central de gestión de aguas residuales, un proceso de eliminación de residuos sólidos y acceso a agua potable tratada. El propósito de este estudio es investigar la calidad del agua subterránea de los pozos excavados y de los pozos tubulares, determinar datos cuantitativos sobre las características del Acuífero de Amarapura y comparar las variaciones estacionales en el flujo y la calidad del agua subterránea. Las muestras de agua se recolectaron durante las estaciones seca y húmeda, luego se analizaron para determinar la química de los iones principales mediante cromatografía iónica para identificar los indicadores del transporte de aguas residuales al acuífero poco profundo y para comparar las variaciones estacionales en la química de las aguas subterráneas. Se usó un modelo de elemento analítico de fuente abierta, GFLOW, para describir la hidrogeología física y determinar las características del flujo de agua subterránea en el acuífero. Los datos de hidrogeoquímica y los modelos numéricos de flujo de agua subterránea proporcionan evidencia de que el Acuífero de Amarapura es susceptible a la contaminación de fuentes antropogénicas. El tipo de agua dominante en la mayoría de los pozos excavados y en los pozos tubulares es Na-Cl, pero no hay una fuente geológica conocida de NaCl cerca de Mandalay. Muchos de estos pozos también contienen agua con alta conductividad eléctrica, cloruro, nitrato, amonio y E. coli. Las mediciones físicas y GFLOW caracterizan las direcciones del flujo de agua subterránea predominantemente hacia el río Irrawaddy y con velocidades lineales promedio que van desde 1.76 × 10^–2 m/día (2.04 × 10^–7 m/s) a 9.25 m/día (1.07 × 10^–4 m/s). Esta es la primera caracterización hidrogeológica realizada en Myanmar. 曼德勒是缅甸中部的一个重要城市,城市人口巨多,缺乏废水中枢管理系统、固体废物处理过程以及缺乏获取处理过的饮用水。本研究的目的就是调查当地挖掘井和管井的水质,确定阿玛拉普拉含水层特征定量数据,对地下水流和水质的季节性变化进行比较。旱季和雨季期间都收集了水样,然后采用离子色谱仪对水样进行了主要离子化学成分分析,以确定废水运移到浅层含水层的污染以及比较地下水化学成分季节性变化。采用开放源解析模型GFLOW描述了物理水文地质状况,确定含水层中的地下水流特征。水文地球化学数据和数值地下水流模型提供的证据表明,阿玛拉普拉含水层易受到人类来源的污染。大多数挖掘井和管井的主要水类型为Na-Cl,但在阿玛拉普拉附近没有已知的NaCl地质源。许多这样的井井水中含很高的电导率、氯化物、硝酸盐、氨和大肠杆菌。物理测量结果和GFLOW结果显示,地下水流方向主要朝向Irrawaddy河,平均线性速度为1.76 × 10^–2 m/天 (2.04 × 10^–7 m/s) 至 9.25 m/天(1.07 × 10^–4 m/s)。这是缅甸进行的第一次水文地质特征描述。 Mandalay é uma importante cidade no centro de Mianmar, com uma grande população urbana e que carece de um sistema centralizado de gestão de águas residuais, de processos de descarte de resíduos sólidos e de acesso a água potável tratada. O objetivo deste estudo é investigar a qualidade da água subterrânea de poços cacimba locais e poços tubulares, gerar dados quantitativos das características do Aquífero Amarapura e comparar as variações sazonais no fluxo e na qualidade das águas subterrâneas. Amostras de água foram coletadas durante as estações seca e chuvosa, e então analisadas mediante cromatografia a química de íons maiores a fim de identificar indicadores de transporte de contaminação de águas residuais para o aquífero raso, e comparar as variações sazonais na química das águas subterrâneas. Um modelo aberto de análise de elementos, o GFLOW, foi usado para descrever a hidrogeologia física e determinar as características do fluxo de águas subterrâneas no aquífero. Os dados hidrogeoquímicos e os modelos numéricos de fluxo de águas subterrâneas forneceram evidências de que o Aquífero Amarapura é suscetível à contaminação de fontes antropogênicas. Os tipos de água dominantes na maioria dos poços cacimba e poços tubulares são Na-Cl, embora não haja alguma fonte geológica conhecida de NaCl perto de Mandalay. Muitos desses poços também contêm água com alta condutividade elétrica, cloreto, nitrato, amônio e E. coli. As medições físicas e o GFLOW determinaram que as direções do fluxo de águas subterrâneas fluem predominantemente em direção ao rio Irrawaddy e com velocidades lineares médias variando de 1.76 × 10^–2 m / dia (2.04 × 10^–7 m/s) a 9.25 m/dia (1.07 × 10^–4 m/s). Esta é a primeira caracterização hidrogeológica realizada em Mianmar.