ECOTERRA - Journal of Environmental Research and Protection www.ecoterra-online.ro 2016, Volume 13, Issue 3 39 Risk assessment of population exposure to nitrates/nitrites in groundwater: a case study approach Carmen Tociu, Ecaterina Marcu, Irina E. Ciobotaru, Cristina Maria National Institute for Research and Development in Environmental Protection, Bucharest, Romania. Corresponding author: C. Tociu, tociucarmen@yahoo.com Abstract. Drinking water is a necessary element for vital activity of population and the presence of nitrates/nitrites in excess may lead to severe health problems. Nitrates/nitrites can reach groundwater as a consequence of agricultural activity (including excess application of inorganic nitrogenous fertilizers and manures) and from oxidation of nitrogenous waste products in human and animal excreta. This study is focused on the evaluation of water quality within a rural area from Romania - i.e. Branesti - which is included on the authorities list of vulnerable areas to nitrate pollution. The aim of the paper was to establish the exposure of population in a more accurate way by the correlation between the content of pollutants in water, characteristics of the population group at risk (e.g. body weight) and the reference dose established in available toxicological research studies. The results indicated frequent concentrations exceeding the limit for nitrates imposed by current regulations concerning the water quality for human consumption, as well as some cases when other chemical and/or bacteriological indicators exceeded the maximum allowable limit. According to the European Drinking Water Directive (Directive 98/83/EC), a need for further monitoring emerged in this rural area together with the need of increasing the awareness of the population towards the health risk posed by nitrate/nitrite contamination. Key Words: hazard index, nitrates/nitrites, rural area, well water. Introduction. The environment plays a significant role in people’s health and well-being. The improvement of environmental quality and the reduction of effects on human health are of a paramount importance for the modern society and progress has been made in this sense, however many threats still remain (Deák et al 2015). In Romania, the physical, chemical and biological parameters of groundwater quality were altered as a result of pollution. Most of hydrological basins were altered due to nitrate contamination. The consequences of pollution are largely different, thus in some area the levels of nitrate are significantly higher than the allowable limit (National Environmental Protection Agency 2015). The factors that affect the contamination of groundwater with nitrates are multiple and often additive, however, the major source is agriculture. Excessive application of fertilizers may cause severe damages as a result of nutrient leaching to the groundwater (Mateo-Sagasta & Burke 2012). There are also other agricultural sources of nitrates. Among these, one may mention manure, effluents from the silos and untreated or insufficiently treated wastewater resulting from farms, which have a significant nutrient content and their leakage may have severe consequences on water quality (Fleșeriu & Oroian 2010). One example of areas vulnerable to nitrate contamination is Brănești – Muntenia Country. This area is located in the Southern part of Romania, on a relatively plain space, with low fragmentation, specific for this area. The characteristics of this area are influenced by the hydro-geographic factors and vegetation and in a less extent by the relief. Taking into account the characteristics of the area, the main economic activity within the Brănești area was agriculture. However, over the last years, the agricultural surface decreased, as a result of construction projects. Within the Brănești area, livestock was not the primary activity. Usually, the manure was used as fertilizer in agriculture. Brănești is located close to an important urban area - Bucharest, thus livestock is not the principal activity within the area. The Brănești area was included by the national authority for the environment on the list of areas vulnerable to nitrate contamination by means of agriculture sources (EU Directive 91/676/CEE). The decision was made based on soil and land conditions, climate and hydrogeological conditions regarding the transfer of the nitrates to the groundwater, as well as on nitrogen balance (nitrogen from the manure – nitrogen from crops) (MO 1552/743/2008).