Phytoremediation of Water Using Phragmites karka and Veteveria nigritana in Constructed Wetland.

Constructed wetland is an innovative and emerging ecological technology for wastewater treatment. This study was conducted to investigate the effectiveness of a Vegetated Submerged Bed Constructed Wetland (VSBCW) for removal of heavy metals from industrial wastewater in a steel manufacturing company. A pilot Effluent Treatment Plant (ETP) consisting of equalization basin, two VSBCW basins and a storage tank was constructed. The VSBCW was constructed using 10-30 mm round granite for the different zones. This was overlaid by 200 mm deep granite and 150 mm washed sand with Phragmites karka, Vetiveria nigritana and Cana lilies as macrophytes. Irrigation of macrophytes using effluent from the industry was done after 3 months of planting and ETP monitored. Industrial wastewater samples were collected and analyzed for heavy metals such as zinc (Zn), lead (Pb), iron (Fe), manganese (Mn), magnesium (Mg) and chromium (Cr) to know the treatment efficiency of the ETP. Results indicated that the removal efficiencies of the VSBCW for Pb, Mg and Cr were 15.4%, 79.7% and 97.9% respectively. Fe and Mn were seen to increase by 1.8% and 33% respectively. The ETP using locally available macrophytes is effective in the phytoremediation of heavy metals, particularly Cr from the wastewater.

Evaluation of leachate treatment by trickling filter and sequencing batch reactor processes in Ibadan, Nigeria.

Strong and highly polluting leachate is continuously discharged into Omi stream and its tributaries in Ibadan, southwest Nigeria, from a municipal solid waste landfill. Previous studies have targeted physical and chemical treatment methods, which could not be implemented on site as stand-alone treatment systems. This study explored the bench-scale, trickling filter (TF) and sequencing batch reactor (SBR) treatment processes and assessed the quality of effluents produced. Leachate treatment using TF produced effluents with significant reductions (%) in suspended solids (SS) (73.17%), turbidity (71.96%), biochemical oxygen demand (BOD5) (76.69%) and ammonia (NH3) (59.50%), while SBR produced effluents with reductions in SS (62.28%), BOD5 (84.06%) and NH3 (64.83%). The dissolved oxygen of the reactors was 4.7 and 6.1mg/l, respectively, in TF and SBR. Also, NH3 values reduced marginally; however, nitrification took place significantly, but within permissible limits. The effluents produced by biological treatment processes were better in quality though the mean residual concentrations for colour, SS and dissolved solids; BOD5 and iron were above the national regulatory standards for discharge into surface water bodies. SBR gave a better effluent quality and should be combined with other treatment methods in sequence to produce quality effluents.

Lead levels in new enamel household paints from Asia, Africa and South America.

In 2006 a report on the analysis for lead in 80 new residential paints from four countries in Asia revealed high levels in three of the countries (China, India and Malaysia) and low levels in a fourth country (Singapore) where a lead in paint regulation was enforced. The authors warned of the possible export of lead-painted consumer products to the United States and other countries and the dangers the lead paint represented to children in the countries where it was available for purchase. The need for a worldwide ban on the use of lead in paints was emphasized to prevent an increase in exposure and disease from this very preventable environmental source. Since the earlier paper almost 300 additional new paint samples have been collected from the four initial countries plus 8 additional countries, three from Asia, three from Africa and two from South America. During the intervening time period two million toys and other items imported into the United States were recalled because the lead content exceeded the United States standard. High lead paints were detected in all 12 countries. The average lead concentration by country ranged from 6988 (Singapore) to 31,960ppm (Ecuador). One multinational company sold high lead paint in one country through January 2007 but sold low lead paint later in 2007 indicating that a major change to cease adding lead to their paints had occurred. However, the finding that almost one-third of the samples would meet the new United States standard for new paint of 90ppm, suggests that the technology is already available in at least 11 of the 12 countries to produce low lead enamel paints for domestic use. The need remains urgent to establish effective worldwide controls to prevent the needless poisoning of millions of children from this preventable exposure.

Environmental risk factors and health outcomes in selected communities of the Niger delta area, Nigeria.

AIMS: The main aim of this study was to assess the prevalence of various health outcomes associated with exposure to environmental risk factors including industrial pollution in selected communities of Nigeria's oil-rich Niger delta area (NDA). METHODS: The study involved both laboratory experiments and community health surveys using questionnaires and hospital records. A total of 14 air samples, 16 grab soil samples and 18 surface water samples were collected and analyzed for physicochemical parameters including heavy metals and polycyclic aromatic hydrocarbons (PAHs) using standard methods. A 77-item questionnaire was administered on randomly selected 349 subjects. A five-year record was collected from health facilities located in the two communities. RESULTS: The laboratory results indicated that the median PAH level at Eleme as compared to Ahoada East was higher than the guideline limit 50 ng/l for surface waters. The mean TSP level at Eleme was higher than the level at Ahoada East and the guideline limit 100 microg/m3. The median PAH level at Eleme was higher than the level at Ahoada East and the guideline limit < 100 ng/m3 for air. The survey results showed that at Eleme air pollution in the community was significantly associated with painful body outgrowths (p = 0.027) and the effect the air contaminants has was significantly associated with respiratory health problem (p = 0.044). At Ahoada East commonly consumed aquatic food was highly significantly associated with painful body outgrowth (p < 0.0001) while use of domestic cooking fuel types was also highly significantly associated with child deformities (p < 0.0001). Hospital records showed high proportions of respiratory disorder among males (3.85%) and females (4.39%) at Eleme as compared to the proportion of respiratory disorder among males (3.68%) and females (4.18%) at Ahoada East. CONCLUSIONS: The study shows that industrial communities such as Eleme, which are exposed to higher levels of air pollution, are more predisposed to respiratory morbidities, skin disorders and other related health risks.

Lead poisoning associated with malaria in children of urban areas of Nigeria.

The principal objectives of this study are to (a) investigate the prevalence of elevated blood lead levels (EBLLs) in children of three major cities of Nigeria with different levels of industrial pollution; (b) identify the environmental, social and behavioral risk factors for the EBLLs in the children; and (c) explore the association between malaria (endemic in the study areas) and EBLLs in the pediatric population. The study involved 653 children aged 2-9 years (average, 3.7 years). The mean blood lead level (BLL) for the children was 8.9+/-4.8microg/dL, the median value was 7.8microg/dL, and the range was 1-52microg/dL. About 25% of the children had BLL greater than 10microg/dL. There were important differences in BLLs across the three cities, with the average value in Ibadan (9.9+/-5.2microg/dL) and Nnewi (8.3+/-3.5microg/dL) being higher than that in Port Harcourt (4.7+/-2.2micro/dL). Significant positive associations were found between BLL and a child's town of residence (p<0.001), age of the child (p=0.004), length of time the child played outside (p<0.001), presence of pets in a child's home (p=0.023), but negatively with educational level of caregiver (p<0.001). This study is one of the first to find a significant negative association between BLL and malaria in a pediatric population, and this association remained significant after controlling for confounding diseases and symptoms. The shared environmental and socio-demographic risks factors for lead exposure and Plasmodium (most common malaria parasites) infection in urban areas of Nigeria are discussed along with possible ways that lead exposure may influence the host response to infection with malarial parasites.

Lead content of dried films of domestic paints currently sold in Nigeria.

Children are at higher risk from lead exposure because their developing neural system is susceptible to its neurotoxic effects. We studied lead levels of paints manufactured in Nigeria in 2006. Lead levels in 5 colors of paints, each from different manufacturers were measured using flame-atomic absorption spectroscopy. We found that 96% of the paints had higher than recommended levels of lead. The mean lead level of paints ranged from 84.8 to 50,000 ppm, with mean of 14,500 ppm and median of 15,800 ppm. The main determinant of lead levels was color of the paint. As lead levels in paint sold in the past years in Nigeria are likely to be at least as high as that currently sold, it is likely that many existing houses contain dangerously high levels of lead. Efforts need to be undertaken to assess the presence of high lead levels in existing housing and if detected, intervention programs for eliminating risk of exposure should be developed in addition to measures to increase awareness and enforce regulations leading to the elimination of lead based domestic paint.

Questionnaire survey of exposure to lead in the domestic environment in Nigeria.

Environmental exposure to lead is a significant cause of morbidity and mortality in developed countries, particularly in children, but remains understudied in developing countries. While prevention is acknowledged as the best public health option, the level of knowledge about lead exposure in many developing countries is not known. We conducted a survey to evaluate the knowledge about lead exposure in Nigeria. Survey questionnaires were developed from the results of focus group discussions and published literature. 600 questionnaires were randomly distributed to adults living in Ibadan, South Western Nigeria in 2004. In addition, the knowledge of lead exposure was measured using a modified version of the Chicago Lead Knowledge Test (CLKT). Information on lead abatement and sources of household lead exposure were also obtained. Most respondents did not have a satisfactory level of knowledge about lead exposure in the domestic environment, how to prevent it and the role of nutrition in diminishing the impact of exposure. Younger people, female and increased years of schooling predict higher scores in the CLKT. Most respondents lived in rented homes; the majority of which were either built or last refurbished in the 1990s. Home owners and people living in homes built or last refurbished within 4 years of the study had higher mean CLKT scores. Our study showed that our respondents had very low levels of knowledge about the risk of domestic exposure to lead, particularly to children. We recommend that efforts should be made to increase awareness of this condition and that in Nigeria as in most development countries; this should be done through the maternal and child health care programs.

An examination of knowledge, attitudes and practices related to lead exposure in South Western Nigeria.

BACKGROUND: Lead is a highly toxic and pervasive metal. Chronic exposure to low levels is responsible for significant health effects, particularly in children. Prevention remains the best option for reducing childhood lead exposure, however the knowledge, attitudes and practices to lead exposure in many developing countries is not known. METHODS: We conducted four focus group discussions (FGD) to evaluate knowledge attitudes and practices to lead exposure in Nigeria. An FGD guide was developed from the literature and preliminary discussion with members of the public. Participants in the FGD were randomly selected from adults living in Ibadan, South Western Nigeria in 2004. RESULTS: We found that there was limited awareness of the sources of lead exposure in the domestic environment and participants had little knowledge of the health effects of chronic low-dose lead exposure. CONCLUSION: We conclude that the findings of this study should be used, in conjunction with others, to develop appropriate health education intervention for lead exposure in the domestic environment.