Impact of cement effluent on water quality of rivers: A case study of Onyi river at Obajana, Nigeria

Physico-chemical characterisation of industrial effluent is of importance in view of its inherent toxic substances. Effluent from cement plant located in Nigeria was characterised and its impact on the receiving Onyi River was investigated in this study. Effluent, water samples from upstream, discharge point along the river course and downstream location were collected monthly. The river was monitored up to about 1 km downstream from the discharge point for a period of twelve months. The impact of the effluent on the water quality downstream was shown by reduced dissolved oxygen. With respect to upstream, the levels of pH, nitrate, phosphate, total solid, total suspended solids, total dissolved solids, turbidity and biological oxygen demand at downstream were much high, arising from the influx of cement effluent. The cement effluent significantly contributed to the levels of Zn (0.045 ± 0.003 mg/L) and Pb (0.016 ± 0.001 mg/L) downstream such that they exceeded the criteria set by USEPA and WHO respectively. Using Prati method of classification of surface water quality, the Onyi River fell in the class of slightly polluted water. Weight arithmetic water quality index of 85.2 and metal pollution index of 3.46 corroborated the classification. Hence, adequate treatment of downstream water prior to its use for beneficial purposes is required

Baseline studies of water quality of Okura River in Kogi State, Nigeria

Water samples from Okura river in kogi state were analysed for some physicochemical parameters and heavy metals to ascertain the water quality. The samples were collected at six sampling points along the river. Results obtained were compared with WHO and other regulatory standard guidelines. Average nitrate and phosphate levels were higher than regulatory guidelines. Total hardness results upstream and downstream were generally low. Overall average concentrations of heavy metals were at baseline levels except Zn with overall average values of 0.37±0.09 and0.23±0.03 upstream and downstream respectively. Okura river fell in the class III Quality of water based on the Prati scale.Keywords: water quality, Okura river, physicochemical, heavy metals, Kogi Stat

Spatial distribution of metal(Ioid)s in groundwater of a mining dominated area : recognising metal(Ioid) sources and assessing carcinogenic and non-carcinogenic human health risk

The study represents the first systematic risk assessment study in East Singhbhum district, Jharkhand, India for the safety of groundwater for drinking purpose with respect to metal(loid)s. The district is known for its mining and related activities. The results demonstrated that concentrations of the metal(loid)s showed significant spatial variation with Al, Mn, Fe, Ni and Zn exceeding the drinking water standards. Principal component analysis resulted in extraction of four factors explaining 76.3% of the data variability. The extracted principal components pointed towards both geogenic and anthropogenic activities governing the groundwater quality. Risk assessment was quantified by the hazard quotient (HQ) and cancer risk for both adult and child. The risk on human health posed by the metal(loid)s was found to be adverse for Mn with HQ > 1 for child. The chronic risks to the local population were largely contributed by Mn, Co and As. However, the carcinogenic risk for As was within the acceptable cancer risk value of 1 × 10−4. Considering the geometric mean of the metal(loid)s in the study area, the hazard index (HI) for adult was above unity. Considering all the locations, the HI varied from 0.23 to 13.03 and 0.20 to 11.15 for adult and child, respectively, suggesting that the groundwater is unsuitable for drinking without treatment at most of the locations

Pyrene and chrysene tolerance and biodegradation capability of pleurotus sajor-caju

Introduction: The present work focused on the biodegradation capability of a white-rot fungus, the Pleurotus sajor-caju, when exposed to polycyclic aromatic hydrocarbons. Methods: The research was carried out by using in vitro systems developed on Petri dishes, to evaluate the fungal tolerance to pyrene and chrysene, followed by experiments in liquid medium. The first experimental campaign was necessary to evaluate the conditions promoting fungal growth and tolerance (presence of surfactants, peptone, copper sulphate and lecithin) and it was designed and analysed using statistical techniques. Results: It was found that the fungal population growth is strongly inhibited by chrysene presence. On the other hand, pyrene had a mild negative impact on the mycelia growth, which seemed to be positively influenced by the presence of Tween 80 and copper sulphate. Starting from these results, the behaviour of Pleurotus sajor-caju in presence of pyrene was investigated in liquid medium. Results showed that the depletion of pyrene was evident during a period of 20 days, and removal efficiency was greater than 90%