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EN
The study aimed to evaluate the spatiotemporal variation in the physico-chemical and bacteriological quality of Oued Inaouène water in relation to urban discharges that remain the main sources of pollution in the Inaouene basin. During the period from May 2019 to March 2020, seven stations were sampled, six of which are spread along the Inaouène Oued in addition to one reference station that is less affected by urban pollution. The indicators used were: temperature, pH, electrical conductivity (EC), turbidity and dissolved oxygen (OD), biological oxygen demand (BOD5), chemical oxygen demand (COD), Kjeldahl nitrogen (TKN), E coli, IE and TC. The quality data obtained were analysed using multivariate statistical methods (the CPA) and the correlation matrix. The results showed that with the exception of the OT station located upstream of urban discharges, the majority of stations downstream of urban discharges have poor quality during both wet and dry seasons, according to the Moroccan standards.
EN
Dayat Roumi Lake, a vast body of permanent and shallow water in Morocco, is exposed to urban, tourist, and agricultural constraints. This human intervention can lead to microbial pollution of the lake ecosystem, hence the need to assess this contamination. For this reason, we undertook in this study an evaluation of the microbiological quality of the lake’s water. Thus, seasonal water samples were taken at eight selected stations, taking into account the reception sites of the tributaries and anthropic activities. The parameters determined were: temperature, pH, dissolved oxygen (DO), electrical conductivity, biological oxygen demand (BOD), chemical oxygen demand (COD), ammonium, nitrates, orthophosphates, total phosphate, total coliforms, fecal coliforms and fecal streptococci. The results reveal: (1) A high water conductivity exceeding the admissible value recommended by the Moroccan standard; (2) A significant presence of coliforms and fecal streptococci, in dry periods, exceeding the standards set by the WHO, which could be attributed to a summer temperature favorable to the development of coliforms. This fecal contamination leads to an increased consumption of dissolved oxygen (high BOD and low DO values) explaining the fish mortality in this period of the year; (3) The principal component analysis identified the sources of water quality degradation as domestic sewage, agricultural run-off, domestic waste, and human and animal excreta; (4) The hierarchical analysis divided the sampling stations into three different clusters. The results of the microbiological quality index classified the waters from not to highly polluted. Station 4 was classified as the most polluted site. The results of the COD/BOD ratio showed a spatial and temporal heterogeneity of the biodegradability of the oxidizable matter present in the lake waters.
EN
The physicochemical and bacteriological quality of groundwater was assessed to show the impact of the agriculture and human activities in the Triffa Plain located in North-East of Morocco. The current levels of contamination of the groundwater were estimated by analysing electrical conductivity, nitrate, nitrite, ammonia, orthophosphate, and indicators of faecal pollution content. Water samples from 55 locations were collected during two period of time, the wet and the dry season of the year 2016. Result obtained indicated that most samples are highly contaminated. The electrical conductivity varied from 800 to 9 100 μS∙cm–1. Nitrate levels ranged from 25 to 216 mg∙dm–3, with 78% of samples exceeding the critical level value set at 50 mg∙dm–3. Nitrate concentrations are slightly higher during the wet period in 73% of studied cases. Nitrite rarely exceeded the normal rate fixed by World Health Organization and reached 0.90 mg∙dm–3. Ammonia and orthophosphate contents do not exceed these norms. The study revealed a wide contamination of groundwater by microbial agents such as, total coliforms, faecal coliforms and faecal streptococci, with content ranged from 0 to 14 000, 0 to 5 000 and 0 to 5 000 CFU∙(100 cm3)–1 respectively, confirming the impact of septic tanks, wastewater discharge into rivers without treatment, and the use of animal waste on the ground water vulnerability. Samplings and measurements were carried out according to the international standard ISO 13395, ISO 11732 and ISO 15681-2 for chemical compounds and ISO 9308-1 and ISO 7899-2 for microbiological numerations.
PL
Przeprowadzono fizyczną, chemiczną i bakteriologiczną ocenę jakości wód gruntowych, aby wykazać wpływ rolnictwa i innych form działalności człowieka na Równinie Triffa w północnowschodnim Maroku. Poziom zanieczyszczeń oceniono przez analizę przewodnictwa elektrolitycznego, stężeń azotanów i azotynów, jonów amonowych, ortofosforanów oraz wskaźników zanieczyszczeń pochodzenia kałowego. Próbki wody pobrano z 55 stanowisk dwukrotnie – w czasie pory suchej i deszczowej w 2016 r. Wyniki analiz wskazują, że większość próbek wody była silnie zanieczyszczona. Przewodność elektrolityczna właściwa zmieniała się od 800 do 9 100 μS∙cm–1. Stężenie azotanów (V) wynosiło od 25 do 216 mg∙dm–3, a w 78% próbek stwierdzono stężenie większe niż wartość krytyczna równa 50 mg∙dm–3. Stężenie azotanów (III) były nieco większe w porze deszczowej w 73% badanych przypadków. Stężenie azotanów (III) rzadko przekraczało normy ustalone przez WHO, osiągając maksymalnie 0,90 mg∙dm–3. Stężenie jonów amonowych i ortofosforanów nie przekraczało wartości normatywnych. Badania wykazały silne skażenie wód podziemnych mikroorganizmami, co przejawiało się dużym zagęszczeniem całkowitym bakterii coli (0–14 000 jtk∙(100 cm3)–1), bakterii coli pochodzenia kałowego (0–5 000 jtk∙(100 cm3)–1) i kałowych streptokoków (0–5 000 jtk∙(100 cm3)–1). Wyniki te potwierdzają wpływ osadników gnilnych, dopływu nieoczyszczonych ścieków i stosowania nawozów naturalnych na jakość wód gruntowych.
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