Evaluation of the bacteriological and physicochemical risk of hospital effluents: case of the Mohamed V hospital in Meknes

Like other countries, Morocco is committed to protecting environment. One of the actions is Law 28 00 on waste because it is harmful to environment and to health. However, hospital effluents are getting out of hand. This study looked at those at Mohamed V Hospital, which serves a population of almost 2 million people. The methodology relates to physicochemical and bacteriological analyzes of representative samples of these effluents by monthly samples over a period of one year. These were carried out in front of the four wings of the hospital between 11 a.m. and noon (maximum activity period). The search for bacteria of medical interest was carried out at the medical analysis laboratory of the Mohamed V hospital. The bacterial count as well as the physicochemical analyzes were carried out at the drinking water & wastewater pollution control laboratory of the Autonomous Distribution Authority of Water and Electricity of Meknes and of the environment and health laboratory of the Faculty of Sciences of Meknes. The results showed that some parameters correlate with others and that these effluents pose a threat to the environment and to health. Indeed, the chemical pollution values are high (NH4 +, NO2-, NO3-) compared to WHO standards. The presence of pathogenic germs is demonstrated such as pseudomonas, acinetobacter, clostridium, staphylococcus and streptococcus. On the other hand, these effluents are biodegradable since the COD / DBOS ratio varies between 1.1 and 2 (<2).


Introduction
Hospitals offer services of various kinds and complexity [1], from simple to more complex procedures such as invasive procedures (surgical procedures, endoscopy, etc.). Indeed, these services allow the care of patients at the level of different care units of the hospital. These generate waste of different kinds. In addition, technological advances in the medical field and the increasingly increased demand for care, lead to an increase in the quantities of waste produced, increasing the risks to human health and the environment [2]. This medical and pharmaceutical waste (D.M.P) is produced by hospitals structures responsible for preventing or reducing risks for patients, professionals and the ecosystem. D.M.P is divided into two types: liquid waste represented by hospital effluents and solid waste [3].
Waste management is unsatisfactory and does not respect the environment; this result has been confirmed by several studies [4]. However, to improve this management, there is no support for effective and appropriate actions; which thus favors an abundance and an increase in negative consequences on environment and on human health [4]. The problem of pollutants' presence in natural environments, especially in water resources, is an international irritation because of environmental, health, strategic, financial and economic issues. Indeed, the generated waste represents between 0.5 and 12 of gross domestic product, of which about one-third for the Healthcare Risk Waste (HCRW) (table I) [5,6].
In this observation, it's interesting to carry out a study whose objective is to determine degree of physicalchemical and bacteriological pollution related to hospital effluents.

Materials and methods
Various physicochemical parameters must be monitored at regular intervals to check physicochemical pollution of discharges. Five-day biochemical oxygen demand, chemical oxygen demand, total suspended solids, total dissolved solids, pH, temperature, exposure time, total nitrogen and total phosphorus are examples of chemical parameters monitored as part of verification [7]. This study was carried out at Mohamed V hospital of Meknes. The frequency of sampling is monthly over a  [13]. The wastewater from each wing flows into its own manhole before reaching the main collector. The latter receives, in addition to the effluents from the four manholes, other wastewater and rainwater Sample to be analyzed must be homogeneous and representative. Since contamination level is higher or lower depending on the place and time of sampling [14,4]. The representative samples consist of manhole water corresponding to each of the four wing constituting the hospital's own care units and during hours corresponding to the maximum amount of care.
Samples are transported to laboratory in an enclosure maintained at an equal temperature close to 5°C (± 3) [15,16]. The water for bacteriological analysis was sampled aseptically in a sterile 500 cc bottle.
Thus the points retained are: • Point 1 (or station 1): Manhole collecting effluents from wing containing the laboratory, the medical imaging unit, the central operating room, the B1 Surgery departments. Cardiac ultrasound unit and the penitentiary service.
• Point 2 (or station 2): Manhole collecting effluents from wing containing the trauma, infantile surgery, neurology, cardiology and nest departments.

Physicochemical parameters
Descriptive statistics of physicochemical parameters are shown in Table II.
Temperature: average temperature recorded is 23,265 ° C and oscillates between 18 ° C and 34 ° C. The maximum temperature, 34 ° C, was recorded at station 4 during the month of June. Thus, these effluents are classified of medium quality according to the Moroccan standard (class 2). High temperatures are recorded during the summer season (June, July and August) and low temperatures are recorded during the winter season.
Hydrogen potential (pH): Results show that hospital effluents comply with biological pH range which is between 6.5 and 8.5 [21] because their pH oscillates between 6 and 8.83 with an average of 7.48. We note that the only months that recorded an alkaline pH are April and September with 8.09 and 8 respectively and that in general effluents from Mohamed V hospital are basic. Dissolved oxygen: Dissolved oxygen testifies to viability of bacterial species. In the present study, it varies from 0.16 mg / l to 12.7 with an average of 2,339 mg / l. The maximum dissolved oxygen value was recorded at station S2 in August, while low values were recorded at station S1 in March and November. Nitrogen compounds: Table III shows the descriptive data relating to nitrogen compounds in effluents of Mohamed V Hospital.

Bacteriological parameters
Clostridium is present with an average concentration of 164 CFU / 100ml (from 7 to 1407 CFU / 100ml). Total coliforms are present with an average of 4.5.10 6 CFU / 100ml with a very significant variation ranging from 8.

Discussion
Temperature: Temperature plays a very important role in solubility of salts and especially gases, and pH determination [22]. It also acts as a physiological factor on growth metabolism of microorganisms living in water. The average temperature recorded is 23,265° C, compared to 18.9 ° C at the same hospital in 2013 [23]. This increase could be explained, first by the fact that effluent pipe passes near boiler and kitchen just before being emptied into view and second by temperature influence of discharges in exit from laundry, from that of oils and fats from kitchen. This result is in accordance with the international standard established by WHO (1986) which sets the maximum temperature at 30 ° C. Thus, these effluents are classified of medium quality according to the Moroccan standard

Hydrogen potential (pH):
Hydrogen potential varies depending on nature of the basic or acidic effluents. It is an indicator of water pollution. The biological pH range is 6.5-8.5, lowering pH can increase toxicity [21]. Results show that effluents from Mohamed V Hospital comply with biological pH range which is between 6.5 and 8.5 [21] because their average pH is 7.48. This pH increased from 2013 when it was 6.9 [23]. We note that in general the effluents from Mohamed V Hospital are basic. According to Moroccan standards, these effluents switch between good and bad quality. In France, the interval is 5.5 to 8.5 [26]. The pH of wastewater from Sidi Kacem hospitals in 2012 was around 7.27 [24]. In Lyon, Boillot noted in 2008 a pH ranging from 5 to 8.8 [27].

Dissolved oxygen:
Dissolved oxygen testifies to the viability of bacterial species. In the present study, its average content of 2,339 mg/l increased by 2.03 mg/l since 2013 [23]. "The classes of aptitude for biology" of the 2nd version of the Evaluation Grids of the System for evaluating the quality of water in rivers classifies these effluents in the red zone and therefore of poor quality [28]. This wastewater is of poor to very poor quality according to Moroccan standards [29].

Conductivity:
Study of the evolution of parameters indicative of salinity has shown that measurement of average electrical conductivity has more than doubled since 2013 (969.67 μs/cm [23]) to reach a value of 2250,51 μs/cm with a very large variation ranging from 62 to 14586 μs/cm. The Moroccan standard classifies these effluents between class 3 and 5 that is to say from average to very poor quality. At Sidi Kacem Provincial Hospital, average conductivity is 3140 μs/cm [24] while Boillot, in Lyon, recorded, for 17 hospitals, an interval ranging from 11.2 to 313 μs / cm [27].

Turbidity (NTU):
Replication of microorganisms is noted by production of turbidity [30]. That, raised is on average 136,77 NTU. We can then say that these effluents are very cloudy since discharge standard is

Nitrogen compounds:
Nitrogen exists mainly in ionic form (ammonium NH4 + , nitrite NO2 and nitrate NO3 -) as well as in gaseous form (N2). Hospital wastewater contains organic nitrogen and ammoniacal nitrogen. The first is an element constituting living cells. The second (NH4 + ) comes from decomposition of organic nitrogen by bacteria and direct discharges (urine, feces). Ammonia and nitrogen dioxide pose problems for public health. They induce bacterial proliferation in water. The main source of concern is NO-3 nitrates. These ions are transformed in a weak acidic medium into nitrite ions which are toxic to human organism. Levels of ammonium, Kjeldahl nitrogen, nitrites and nitrates are all in excess of discharge standards set by WHO [28]. By comparing our results with Moroccan standards [29], we can advance that in terms of ammonium and Kjeldahl nitrogen, effluents from Mohamed V hospital are classified as very bad (NH4 +> 8mg / l and NTK> 3mg/l), while in terms of nitrates, they are classified as of medium quality (NO3-between 25 and 50 mg/l).

Orthophosphates:
The average phosphate levels (21,65 mg/l) increased since they were at a value of 10.65 mg/l in 2013 [23] and. They exceed WHO phosphate standard, which is set at a content of less than 2 mg/l [28]. While for Boillot, in Lyon, they are between 6.15 mg/l and 17.3 mg/l [27].

Results by parameter (analysis):
Descriptive statistics of physicochemical parameters are presented in Table II Analysis of results shows that most of information is explained by the first two factor axes.
The formation of factorial axes F1 and F2 is characterized by the fact that no parameter contributes more than 20% (table IV). Based on the principle that only variables whose contribution is greater than the average contribution are retained for interpretation (Table IV)      Physico-chemical analyzes of effluents from Mohamed V hospital concluded that these present both organic and mineral pollution with reference to national and WHO standards. Results showed that these effluents pose a threat to environment and health. Indeed, chemical pollution values are high (NH4 + : avg = 59.6 mg/l against WHO standard of 0.5 mg/l; NO2 -: 3.7 mg/l against WHO standard which is l mg/l; NO3 -: 34.54 mg/l against WHO standard which is 1 mg/l; Kjeldahl nitrogen (NTK): 60.21; orthophosphates PO4: 18.56 mg/l). On other hand, Mohamed V hospital effluents are biodegradable since average COD / DBOS ratio is 1.76 (<2).

Evolution of physico-chemical parameters over the years:
Effluents of Mohamed V Hospital in Meknes change over time. To follow this evolution, we compared our results for certain parameters with those of 2013 (23) for the same hospital. • Temperature: over years, effluents of Mohamed V hospital have gained almost 4 ° C between 2013 and 2016. • The pH: it has evolved with + 0.4 • The conductivity rose from 969 to 2611, ie an increase of + 270%. • The ratio between dissolved oxygen content of our study and that of 2013 is equal to 3.74. • SM fell by almost half • BOD5 and COD lost 25% and 32% respectively from 2013 currently. • Nitrite concentration fell by 80%, going from 18.09 mg/l in 2013 to 3.7 mg/l now. On other hand, nitrate content increased more than ten times, going to 34,54 mg/l currently after having been at 3.19 mg/l. • Orthophosphates increased by a coefficient of 1.74.

Conclusion
Results showed that some parameters correlate with others and that these effluents pose a threat to environment and to health. Indeed, chemical pollution values are high (NH4 +, NO2-, NO3-) compared to WHO standards. Presence of pathogenic germs is demonstrated such as pseudomonas, acinetobacter, clostridium, staphylococcus and streptococcus. On other hand, these effluents are biodegradable since the COD / DBOS ratio varies between 1.1 and 2 (<2).