**2.2 Medical geology and ONE HEALTH approach in health risks assessment of drinking water in Haiti**

Located between 18° and 20°6' Northern latitude and between 71°20<sup>0</sup> and 74°30' Western longitude, Haiti divides with Dominican Republic "the island of Hispaniola" which is the second biggest island of the Caribbean. Its capital, Port-au-Prince, is settled at the bottom of the Gulf of "La Gonâve", in the south border of Plain of Cul-de-sac and in the north catchment area of the "Massif de la Selle" piedmont (**Figure 1**). The main municipalities which constitute urban community of Port-au-Prince are Port-au-Prince, Delmas, Pétion-ville, Croix-des-bouquets, Gressier and Carrefour.

Haiti is exposed to a considerable ecological imbalance, characterized by catastrophic flooding associated to torrential rains and hurricanes, devastating earthquakes, and deforestation [50]. Other problems, resulting from this imbalance include land use forming the immediate perimeter of headwaters and wells, wetlands draining, arable soils erosion, the decrease of the headwaters flow and groundwater, seawater intrusion, sewers obstruction and fecal pollution [51]. In addition, Haiti is one of the most vulnerable countries to climate change [52]. In general, Haiti's geophysical environment is characterized by rugged relief. Most of the territory is occupied by mountains formed of limestone and karst aquifers [31, 53–55]. The existence of karst aquifers conditions in rainy weather the contamination of groundwater by surface pollution. Indeed, the main characteristics of

#### **Figure 1.**

*Map of the west department of Haiti and metropolitan area of Port-au-Prince [49].*

karst aquifers are the existence of irregular networks of pores, cracks, fractures and pipes of various shapes and sizes. Such a structure, of significant physical and geometric heterogeneity, causes complex hydraulic conditions and the spatial and temporal variability of hydraulic parameters. After a downpour, rapid and turbulent groundwater recharge occurs through drainage in large conduits with high volume of unfiltered water [56].

Groundwater resources at Port-au-Prince are vulnerable to contamination related to polluted water infiltration such as leachates, cesspools and septic tanks, stormwater runoff, waste oil discharging, over-irrigation and industrial discharging [50]. These sources of groundwater recharge may contain organic and inorganic compounds which can be in dissolved and colloidal forms or associated to particles. Microbiological and physicochemical characterization of groundwater resources in the metropolitan area of Port-au-Prince, among other things, highlight the presence of heavy metals [57], fecal coliforms [27] and Cryptosporidium oocysts [58]. In addition to bacterial and metal contaminations, it was found that aquifers in Haiti are also exposed to seawater pollution [50]. According to Gonfiantini and Simonot [59], the salt water is slightly enriched with heavy isotopes with respect to fresh groundwater, not showing any deviation from the straight line of meteoric waters. In the area of Port-au-Prince, the salinity of the groundwater is the result of seawater intrusion because of intensive exploitation [59].

The geophysical environment of Port-au-Prince, the inefficiency of the sanitation system (collection and treatment of solid waste, drainage, and treatment of wastewater, etc.), which contribute to the microbiological and physicochemical quality of the water distributed by public networks to the population gives rise to a particular epidemiological environment where the water generates several dangers for the health of consumers. In such a context, the assessment and management of health risks associated with water intended for human consumption require a multidisciplinary approach and call on researchers, technicians, and specialists in several fields of life and earth sciences as well as the humanities and social sciences.

The 2030 Agenda for Sustainable Development of the United Nations (UN) establishes goals and targets in areas of critical importance for humanity [60, 61], Ramirez-Mendoza et al., 2020 [62]. Indeed, the SDGs are linked to one another, the success of one often depending on the resolution of problems generally associated with another objective [60]. They thus constitute a universal and transversal approach concerning all countries, in the North as in the South. Regarding the issue of water, objective 6 - access to safe water and sanitation - aims to meet the challenges of drinking water, sanitation, and hygiene for populations, as well as issues concerning aquatic ecosystems. In the absence of quality and sustainable water resources and sanitation, progress in several other areas of the Sustainable Development Goals, including health, education and reduce of poverty, will also be delayed [60]. This objective, taken in the prism of the situation of the urban and hydrological context, as well as the geophysical environment of Haiti, raises concerns. However, the launching by public authorities and funding agencies of large research programs with the objective of generating and applying knowledge, promoting innovations in the life and earth sciences, as well as in human and social sciences, in a context of transdisciplinary would be of great use, even essential for the development to achieve the various objectives [63]. Indeed, Medical geology, the science that deals with the relationship between natural geological factors and human and animal health problems [32], and the One Health approach, an approach that attempts to bringing together medical/public health researchers, veterinary researchers, and environmental scientists to tackle health problems, provides an adequate theoretical framework to address environmental health problems resulting from the degradation of natural environment in Port-au- Prince.

#### *Chemical Pollution of Drinking Water in Haiti: An Important Threat to Public Health DOI: http://dx.doi.org/10.5772/intechopen.97766*

The interconnectedness of human, animal, and environmental health is at the heart of One Health, an increasingly important prism through which governments, NGOs (nongovernmental organizations), and practitioners view human health) [64]. Mazet et al., [65] note "An important implication of the One Health approach is that integrated policy interventions that simultaneously and holistically address multiple and interacting causes of poor human health—unsafe and scarce water, lack of sanitation, food insecurity, and proximity between animals and humans will yield significantly larger health benefits than policies that target each of these factors individually and in isolation. By its very nature, the One Health approach is transdisciplinary, since it is predicated on agricultural scientists, anthropologists, economists, educators, engineers, entomologists, epidemiologists, hydrologists, microbiologists, nutritionists, physicians, public health professionals, sociologists, and veterinarians working collaboratively to improve and promote both human and animal health" [65].
