There is no unified water quality monitoring system or practice in Moldova.

Surface water quality is classified into 4 classes, from class I (good quality) and II (moderately polluted), to class III (polluted) and IV (very polluted) for low-quality waters.  The water quality of the Nistru and Prut rivers, as well as of the lakes and reservoirs, is generally satisfactory and in line with the quality standards in force.  The mineralization of water increases from 290-450 mg/l total dissolved solids in the upper reaches of the Nistru (Otaci section) to 365-578 mg/l in the Olanesti section.  In comparison with the 1950s, the mineralization of Nistru water has increased by 50%.  A characteristic of the Nistru and Moldova's other rivers is their high turbidity.  For example, in 1993, the average annual turbidity in the Olanesti section was 462 mg/l TU (turbidity unit).

During the past two decades, concentrations of nitrogen and phosphorus have increased to 10 mg/l and 0.2 mg/l, respectively.  These two levels do not exceed the standard limits for drinking-water supply, but they are rather high and are causing eutrophication, particularly in the Dubasari water basin.  Downstream from Soroca, Camenca, Bender and Tiraspol, ammonia (up to 0.7 mg/l) and nitrogen (up to 0.2 mg/l) can be found as a result of residual water overflow that is insufficiently treated.  Also, increasing quantities of petroleum substances (0.08 mg/l), phenols (0.02 mg/l) and detergents (0.06 mg/l) have been recorded.

The concentration of heavy metals accumulated on the bed of the Dubasari reservoir exceeds 400 times their concentration in the upstream river water, which is otherwise acceptable.  The bacteriological analyses of Nistru water have detected 1.102 to 2.103 faecal coliform germs per 100 ml, reaching 2.103 - 2.104 per 100 ml in some places.  On the whole, the water of the Nistru River is moderately polluted (i.e. class II), but is polluted at the confluence with the rivers Raut and Bac (i.e. quality class III).

Prut water is especially polluted by organic substances.  Its level of microbial infection is quite high: the total number of faecal coliform bacteria is 3.105 per 100 ml at Ungheni, 2.5.  105 per 100 ml at Leova and Giurgiulesti.  Retroviruses are periodically found (in 1994 at Leuseni and Cahul).  The water of the river Prut generally falls into the class of moderately polluted water, but downstream from Ungheni, the water is polluted, even reaching the category 'strongly polluted' (i.e. class IV) near Valea Mare.  The water of most small rivers falls between the classes 'polluted' and 'strongly polluted'.

In some places, groundwater is contaminated down to a depth of 12-14 m as a result of agricultural misuse of mineral fertilizers, pesticides and inefficient treatment of agro-industrial wastes - sometimes because of oil leakage.  About 57% of rural wells are polluted with nitrogen compounds, pesticides, hydrogen sulphide and fluorides (especially in deep wells).  However in recent years, the maximum concentration of nitrates measured in the drinking water of decentralized systems has rarely exceeded 150 mg/l-250 mg/l.  These levels were much higher in the 1980s.  Nitrates, ammonium, pesticides, as well as heavy metals, are also detectable in surface waters.

From the total quantity of groundwater, only 25% can be used for economic purposes without pretreatment, because of the generally high mineralization (2.5-3 g/l), naturally high content of fluorine (5-15 mg/l), and high concentrations of ammonia nitrogen (15-20 mg/l), hydrogen sulphide and methane (up to 10 mg/l).
Groundwaters under 60% of the country's territory do not satisfy drinking-water requirements.  Half the drinking-water supplies from groundwater in the Prut basin have nitrate concentrations in excess of 45 mg/l (both WHO guideline and Moldovan standard).  The drinking water in a good half of the village wells is estimated to be polluted with agricultural chemicals or their decay products.

The artesian groundwaters have so far not been seriously polluted by anthropogenic sources thanks to their surface insulation with protecting layers.

By contrast, phreatic waters undergo intensive anthropogenic pollution mainly from nitrates (in some places up to 1 000-2 000 mg/l), the main sources being livestock complexes and farms, rural settlements not equipped with sewer systems, uncontrolled waste disposal, and excess use of mineral fertilizers.

The percentage of drinking water samples not meeting the standards is almost twice as high in decentralized systems (wells) than in the communal water distribution systems (Table 8.2).

Starting in 1996, more detailed information on the sanitary-chemical parameters is recorded based on a subset of samples subject to a more specific analysis. The results indicate that less than 16% of samples from communal systems which fail to meet sanitary-chemical quality criteria contain nitrates in concentrations exceeding the standard (45 mg/l, see Table 8.3). However, a high level of nitrates is found in most of the samples failing sanitary-chemical standards in decentralized sources
 

Table 8.2:  Samples not meeting drinking water quality standards, 1993-1996

 
Source:  Materials of the Ministry of Health* and NCSAHE**.
of drinking water. In recent years, the maximum concentration of nitrates measured in the drinking water of decentralized systems has only rarely exceeded 150 mg/l, and 250 mg/l. These levels were much higher in the 1980s, before agriculture activity started to decline.

Table 8.3:  Monitoring of nitrates in drinking water , 1996

 
Source:  Materials of NCSAHE.

In some regions of the country (Nisporeni, Ungheni, Falesthi, Calarashi), populated by more than 500 000 people, groundwater contains fluoride in concentrations of 5-12 mg/l (the WHO water quality guideline is 1.5 mg/l). Consumption of this water without removal of excess fluoride leads to fluorosis. It has been reported that up to 25% of the population in selected towns of high-fluoride areas show symptoms.

In a limited number of samples, the presence of pesticides was tested as well. In 1996, in seven out of 879 samples taken from decentralized drinking water sources (i.e. in  0.8% of the samples), the concentration of pesticides exceeded standard levels (though the measured levels were low, close to the limit of detection). It is suspected that the contamination might have occurred due to an accidental spillage of the chemicals into the water source. In none of the 215 samples taken from communal water supply systems was an excess of pesticides detected.