мая 08 2003

The quality of ground and artesian waters In the republic of Moldova

Опубликовано в 18:05 в категории Чистота воды и здоровье

The quality of ground and artesian waters In the republic of Moldova

N.V. Goreaceva, V.I. Gladchi, E. Bunduchi, I. Mardari

State University of Moldova, Chisinau

For rural population of Moldova the primary sources of drinking water are ground and artesian waters. In order to reach the groundwater, the population is digging wells that currently achieved the number of 126000. The number of artesian wells was estimated to be around 5600, considerable parts of which are not in use, again, due to economic deficiencies. Various information sources stipulate that about 80% of existing wells contain waters of bad quality and dangerous for human health. Groundwaters of the Republic of Moldova are characterized by increased mineralization and hardness, increased content of nitrogen compounds such as nitrates, nitrites, and ammonium ions. The content of nitrates in waters from wells is very high, exceeding by 2 - 10 times the maximum admissible levels. Other identified pollutants including pesticides, phosphates, oil products, phenols and heavy metals were exceed the permissible levels as well.

The artesian wells from rural localities are used mostly for water supply to schools, hospitals, kindergartens, and cattle farms. The qualities of artesian waters vary substantially from place to place. Some of them are characterized by an increased content of ammonia nitrogen, iron, salts responsible for water hardness, very high or very low fluorine content, excessive content of strontium. The artesian waters are transported to customers usually untreated. At the same time, the number of exploited artesian wells has declined during last years due to economic deficiencies. The wells are exploited without adequate preventive maintenance, which cause their degradation.

Therefore, provision of drinking water to rural localities encounters certain technical and economic difficulties. The volume of extracted drinking water and supplied to inhabitants of rural localities of the Republic of Moldova is decreasing.

Taking into account that 54 % of the population of the republic lives in rural areas, there can be drawn the conclusion that almost a half of the population consumes water of bad quality which is often dangerous for human health.

During last years a big part of population had to use for food and drinking purposes very bad water, which caused an increase of the morbidity. Responsible for the quality of life, including the assurance of the good quality water is the village authority.

With the purpose to evaluate the quality of drinking water from various regions of the country, we have collected 339 samples of drinking water. The hydro chemists of the organization have analyzed the chemical composition of the samples and have drawn up the following findings.

The influence of natural and anthropogenic factors is responsible for generation of ground waters with varying chemical composition. Waters from deeper horizons have a mineralization ranging from 400 to 1900 mg/l, hardness varying from 0,3 to 211 mmol/l. The sulfate ions content varies in dependence of its mineralization within the limits of 7.5 – 300 mg/l, while chlorine ions - within the limits 12-410 mg/l. Some artesian wells are characterized by an increased content of hydrogen sulfide and iron. The content of iron in groundwater varies from very small (0.01 mg/l) to very high quantities (7.0 mg/l). In artesian wells sometimes high quantities of ammonium nitrogen, reaching 13.1 mg/l, can be detected. A considerable part of artesian wells contain water of very bad quality with regard to fluorine content, its quantity constituting from 0.0 mg/l to 3.8 mg/l.

The territory of Moldova is characterized by uneven composition of ground waters of low pressure. On a territory of small size can be encountered wells that have very different chemical composition. The total content of mineral salts in groundwater wells varies in large limits from 500 to 5500 mg/l. The sulfate content of these wells constitutes 24 – 1000 mg/l, and chlorine 20 – 670 mg/l. About 60% of wells contain waters with mineralization higher than 1500 mg/l. The total hardness of groundwater of the republic varies within the limits 0.8 – 41 mmol/l. In 72 % of wells the water hardness exceeds 10 mmol/l.

A very important characteristic of waters from wells located on the territory of the Republic of Moldova is the increased content of nitrates. The content of nitrates in ground waters varies within the limits 10.0 mg/l – 790 mg/l in dependence of the wells location and sanitary and hygienic state around them. It is terrible the fact that in 86% of wells the level of nitrates is exceeding the maximum admissible level of 45 mg/l.

In the ground water of some villages increased quantities of ammonium nitrogen (up to 2.6 mg/l), of nitrites (up to 0.75 mg/l), of manganese ions (more than 0.2 mg/l) were detected. For example, in the Cretoaia village of Chisinau district manganese is present in quantities from 0.1 to 2.7 mg/l in all the 28 wells of the locality.

The obtained data indicates that waters extracted for drinking purposes are of very bad quality and a big part of them represents a real threat for human health.

In case of centralized provision of drinking waters from artesian wells, 54.5% of sources contain ammonium nitrogen exceeding the maximum permissible levels; the mineralization exceeds the permissible concentrations in 10% of the wells. The permissible hardness is not met in 50% of the wells (including those wells where this parameter is less than 1.5 mmol/l), 22 % of artesian wells contain water that does not meet the standards with regard to iron content; 71 % do not meet the requirements for fluorine (in 55% of the sampled wells, the fluorine content exceeds the allowed limits, while in 16% of the cases the fluorine content is lower than the required minimum).

A serious threat is represented by the lasting or continuous consumption of ground waters. The analysis of such waters has proved that 55% of wells contain excessively mineralized waters. The hardness is quite high in 72% of the investigated cases; concentrations of nitrates above the permissible levels were detected in 86 % of the wells. Numerous wells provide waters, which contain fluorine in quantities higher than the permissible levels, or lower than it is necessity. The manganese and other metals were detected often in quantities exceeding the adopted norms.

It is necessary to take into account the fact that lasting consumption of waters lacking mineral salts (mineralization is high or low) or fluorine and containing heavy metals, nitrates, nitrites and ammonium salts can cause serious illnesses. It is well known the fact that continuous consumption of highly mineralized waters is responsible for increased sugar in blood, and adverse influence on lipid transformations in human body. Statistical data indicates that consumption of water with hardness exceeding 15 mmol/l can induce bone diseases and accumulation of kidney stones. At the same time, consumption of water with hardness lower than 1.5 mmol/l can induce cardiovascular diseases.

The humans consuming waters, in which the content of nitrates exceeds 45 mg/l, are facing the risk of chronic intoxication of the organism, which is often followed by changes of nervous system and in liver. The adverse effect of nitrates and nitrites is manifested especially in children and can induce their acute intoxication.

The continuous consumption of waters containing increased levels of iron (more than 0.3 mg/l) is responsible for liver illnesses and increases the probability of heart attacks.

The excess of manganese in drinking water (exceeding 0.1 mg/l) is related to various bone diseases.

The only source of fluorine for our bodies is water. Absence of deficiency of fluorine in water (lower than 0.45 mg/l) can cause dental caries, while its excess (quantities higher than 1.5 mg/l) causes fluorosis. In extreme cases when the content of fluorine exceeds 3.0 mg/l the fluorosis can affect the entire bone system.

The situation is aggravated by the fact that population is not informed about the quality of drinking water, and the state bodies, due to economic crisis, are not able to assure a systematic control of water quality from all the sources used by large population. The sanitary and epidemiological system is controlling the quality of water only in 1 % of existing sources of drinking water.

Аннотация

К статье «Качество грунтовых и артезианских вод

в Республике Молдова»

Н. В. Горячева, В. И. Гладкий, Е.Г. Бундуки, И.Н. Мардарь

Грунтовые и артезианские воды в сельских районах Молдовы являются основными источниками питьевых вод.

По разным литературным и ведомственным данным из имеющихся в республике 126000 колодцев около 80% содержат воды очень низкого качества, представляющие опасность для здоровья. Они характеризуются повышенной и очень высокой минерализацией, жесткостью, загрязненностью нитратами, аммонийными солями, другими токсическими веществами.

Качество артезианских вод зависит от гидрогеохимических условий формирования вод подземных горизонтов, которые отличаются по территории Молдовы. В некоторых из них присутствуют недопустимые нормами большие или малые концентрации фтора, повышенное содержание аммонийного азота, железа, стронция.

В работе приводятся данные собственных полевых исследований качества подземных вод, используемых сельским населением различных районов Молдовы для питьевых целей.

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