Faridah Hussein Were

Use of human nails as bio-indicators of heavy metals environmental exposure among school age children in Kenya

Metal pollution and its health effects present a challenge currently facing the developing countries. Metal poisoning is usually difficult and expensive to assess or screen in these countries due to limited resources, which means that policies, guidelines, regulations and institutional managements are limited. Hair and nail as biopsy materials were suggested as more attractive biomarkers in assessing heavy metals environmental exposure. This paper deals with quantitative determination of lead (Pb), cadmium (Cd), calcium (Ca), zinc (Zn), and iron (Fe) in fingernails of children (n=200) in urban and rural areas using atomic absorption spectrometry. Factors that were suspected to influence the accumulation of Pb and Cd in children were obtained through a questionnaire. The mean levels of heavy metals in children in urban areas were found to be higher (27.5+/-1.8 microg/g Pb and 0.73+/-0.08 microg/g Cd) than in rural areas (19.7+/-0.9 microg/g Pb and 0.44+/-0.06 microg/g Cd). The difference was significant (P<0.05; DF=168, t-test). Other factors that were found to have significant influence were socio-economic background, health conditions, dietary habits and environmental risk exposure. The results also showed that the school location has more influence on the heavy metals level than the area of residence. The children in a school near the highway were found to have a mean of 34.4+/-3.5 microg/g Pb as compared to those who lived near the highway (31.6+/-2.8 microg/g Pb), however the difference was not significant (P>0.05), suggesting a common source of contaminants in the areas. The correlation results also indicated that a high level of Pb in the nail influenced negatively Zn and Fe but not Ca levels (R=-0.256 Zn; -0.188 Fe) while high levels of Cd had a negative relationship with Fe only (R=-0.241). The association of toxic metals in the nails of children with environmental exposure, and nutritional status implies that policies and actions to reduce heavy metal levels must be implemented and reinforced to address the health issues affecting children and by extension the general public in this country.

Air and Blood Lead Levels in Lead Acid Battery Recycling and Manufacturing Plants in Kenya

The concentration of airborne and blood lead (Pb) was assessed in a Pb acid battery recycling plant and in a Pb acid battery manufacturing plant in Kenya. In the recycling plant, full-shift area samples taken across 5 days in several production sections showed a mean value ± standard deviation (SD) of 427 ± 124 μg/m3, while area samples in the office area had a mean ± SD of 59.2 ± 22.7 μg/m3. In the battery manufacturing plant, full-shift area samples taken across 5 days in several production areas showed a mean value ± SD of 349 ± 107 μg/m3, while area samples in the office area had a mean ± SD of 55.2 ± 33.2 μg/m3. All these mean values exceed the U.S. Occupational Safety and Health Administrations permissible exposure limit of 50 μg/m3 as an 8-hr time-weighted average. In the battery recycling plant, production workers had a mean blood Pb level ± SD of 62.2 ± 12.7 μg/dL, and office workers had a mean blood Pb level ± SD of 43.4 ± 6.6 μg/dL. In the battery manufacturing plant, production workers had a mean blood Pb level ± SD of 59.5 ± 10.1 μg/dL, and office workers had a mean blood Pb level ± SD of 41.6 ± 7.4 μg/dL. All the measured blood Pb levels exceeded 30 μg/dL, which is the maximum blood Pb level recommended by the ACGIH®. Observations made in these facilities revealed numerous sources of Pb exposure due to inadequacies in engineering controls, work practices, respirator use, and personal hygiene.

Lead Exposure and Blood Pressure among Workers in Diverse Industrial Plants in Kenya

The study evaluated airborne exposures and blood lead (BPb) levels in 233 production workers at six diverse industrial plants in Kenya. Blood and personal breathing zone air samples were collected and analyzed for lead (Pb) using atomic absorption spectroscopy. Blood pressure (BP) levels were measured using a standard mercury sphygmomanometer. The results indicated mean airborne Pb levels ± standard deviation (SD) as follows: 183.2 ± 53.6 μg/m3 in battery recycling, 133.5 ± 39.6 μg/m3 in battery manufacturing, 126.2 ± 39.9 μg/m3 in scrap metal welding, 76.3 ± 33.2 μg/m3 in paint manufacturing, 27.3 ± 12.1 μg/m3 in a leather manufacturing, and 5.5 ± 3.6 μg/m3 in a pharmaceutical plant. The mean airborne Pb levels exceeded the U.S. Occupational Safety and Health Administration (OSHA) 8-hr time-weighted average (TWA) permissible exposure limit (PEL) for Pb of 50 μg/m3 in the battery manufacturing, battery recycling, welding, and paint manufacturing plants. Similarly, mean BPb concentrations exceeded the American Conference of Governmental Industrial Hygienists (ACGIH®) biological exposure index (BEI) for Pb of 30 μg/dl. A significant positive association was observed between BPb and breathing zone air Pb (R2 = 0.73, P < 0.001). Approximately 30% of the production workers (N = 233) were in the hypertensive range with an average systolic and diastolic blood pressure (BP) of 134.7 ± 12.7 mmHg and 86.4 ± 8.9 mmHg, respectively. In the multivariate regression analysis, age, duration of work, airborne Pb and BPb levels were significantly associated (P < 0.05) with a change in BP. We recommend improved engineering controls, work practices, and personal hygiene to reduce Pb exposures. In addition, workers should undergo comprehensive medical surveillance to include BPb and BP testing, and airborne Pb assessments in all industries with significant lead exposures.

Soil contamination from lead battery manufacturing and recycling in seven African countries.

ABSTRACT Lead battery recycling is a growing hazardous industry throughout Africa. We investigated potential soil contamination inside and outside formal sector recycling plants in seven countries. We collected 118 soil samples at 15 recycling plants and one battery manufacturing site and analyzed them for total lead. Lead levels in soils ranged from < 40–140,000 mg/kg. Overall mean lead concentrations were ˜23,200 mg/kg but, average lead levels were 22‐fold greater for soil samples from inside plant sites than from those collected outside these facilities. Arithmetic mean lead concentrations in soil samples from communities surrounding these plants were ˜2600 mg/kg. As the lead battery industry in Africa continues to expand, it is expected that the number and size of lead battery recycling plants will grow to meet the forecasted demand. There is an immediate need to address ongoing exposures in surrounding communities, emissions from this industry and to regulate site closure financing procedures to ensure that we do not leave behind a legacy of lead contamination that will impact millions in communities throughout Africa. HIGHLIGHTSSoil lead contamination was found at lead battery recycling facilities in Africa.Mean lead concentrations were 2600 mg/kg in soil on the outside of plants.Lead pollution at these sites poses significant health risks to the public.Lead contamination at these plants suggest that extensive remediation is warranted.

Chromium Exposure and Related Health Effects among Tannery Workers in Kenya

Background. There is increasing concern over the health effects of chromium (Cr) exposure stemming from various activities in tanneries in Kenya. Chromium is a toxic metal in its hexavalent form, a...

Respiratory Diseases Due to Occupational Exposure to Nickel and Chromium among Factory Workers in Kenya

Inhalation of airborne nickel (Ni) and chromium (Cr) in workplaces causes a variety of respiratory ailments which adversely affects the productivity of employees. A study was therefore conducted on production workers (N=233) from six different types industrial plants, to investigate the influence of Ni and Cr exposure on their respiratory systems. Breathing zone air and urinary samples were collected, and analyzed for total Ni and Cr using atomic absorption spectroscopy. The medical history of the workers was obtained using questionnaires. Their lung functions were further examined using a spirometer. Mean (± standard deviation) breathing zone air of 23.4 ± 11.6 μg/m3 Cr and 10.3 ± 4.3 μg/ m3 Ni was highest among the tanners and welders, respectively. The mean level of 35.2 ± 12.1 Cr and 28.4 ± 7.8 Ni in μg/g creatinine were also highest in the urine of corresponding workers. A significant (P<0.01) correlation of r=0.86 Cr and r=0.89 Ni was observed between airborne and urinary levels in all production workers. Approximately 26.6% of the workers had respiratory diseases that were associated with wheezing, shortness of breath, sneezing attacks among other related symptoms. Most of these workers were welders, tanners and, to lesser extent, paint manufacturers. The breathing zone air of the afflicted workers had significantly (P<0.05) high mean levels of 6.4 ± 4.4 μg/m3 Ni and 9.6 ± 5.3 μg/m3 Cr than those who were not affected (3.9 ± 3.2 μg/m3 Ni and 4.4 ± 3.8 μg/m3 Cr). A high proportion of the workers had reduced ventilatory function measurements. We recommend comprehensive assessment of Cr and Ni in related industries with significant exposures. Designing and developing of training programs and educative manuals on safety and health procedures, and regular medical surveillance is also recommended.

Child Exposure to Lead in the Vicinities of Informal Used Lead-Acid Battery Recycling Operations in Nairobi Slums, Kenya

Background. Child exposure to lead from informal used lead-acid battery (ULAB) recycling operations is a serious environmental health problem, particularly in developing countries. Objectives. We investigated child exposure to lead in the vicinities of ULAB recycling operations in the Dandora, Kariobangi and Mukuru slums in Nairobi between January and August 2015. Methods. Top soil (n = 232) and floor dust (n = 322) samples were collected from dwelling units (n = 120) and preparatory schools (n = 44) and analyzed using an inductively coupled plasma-optical emission spectrometer at the Mines and Geological Department Laboratory in the Ministry of Mining, Nairobi. From the obtained lead levels in soil and house dust, child blood lead levels were subsequently predicted using the Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK), Windows version. Results. Lead loadings in all the floor dust samples from the Dandora, Kariobangi and Mukuru slums exceeded the United States Environmental Protection Agency (USEPA) guidance value for lead on floors with a range of 65.2 – 58,194 μg/ft2. Control floor dust samples recorded lower lead loadings compared to the Dandora, Kariobangi and Mukuru slums. Lead concentration in 70.7% of the soil samples collected from waste dumps, industrial sites, residential areas, playgrounds and preparatory schools in Dandora, Kariobangi and Mukuru exceeded the respective USEPA guidance values for lead in soils. Lead concentration in 100% of control soil samples were below the respective USEPA limits. The IEUBK model predicted that nearly 99.9% of children ≤ 7 years old living near informal ULAB recycling operations in Dandora, Kariobangi and Mukuru were at risk of being lead poisoned, with predicted blood lead levels (BLL) above the Centers for Disease Control (CDC) reference value for blood lead. A total of 99.9% of exposed children living in the Mukuru slums are likely to have BLL above 34 μg/dL. Conclusions. There is a need for coordinated efforts to decrease lead emissions from informal battery recycling in Nairobi slums and to remediate existing soils, particularly around battery workplaces and dumpsites. The BLL of local children should be clinically tested and appropriate intervention measures taken.

Phytoremediation using bamboo to reduce the risk of chromium exposure from a contaminated tannery site in Kenya

Background. This study examines an intervention strategy to reduce the risk of chromium (Cr) exposure. It follows a previous Cr exposure investigation, which revealed that large volumes of Cr-contaminated waste were burnt on site. The study site had a long history of land-based waste disposal since 1994. Objective. The potential for phytoremediation using bamboo species to restore Cr-contaminated soil was evaluated. Methods. Chromium levels and physico-chemical properties of the tannery and control soils were analyzed before transplanting six different bamboo species. Translocation, bio-concentration and bioaccumulation factors of the species were assessed for phytoremediation capabilities. Results. Chromium levels in the tannery soils ranged from 1337.0 to 3398.0 mg/kg dw. The chromium levels were significantly higher (P < 0.05) than those of the control soils (0.20 to 2.34 mg/kg dw) and markedly exceeded the recommended limit of 100 mg/kg dw. The physicochemical properties of the tannery soils were also significantly varied (P < 0.05) compared to the control soils. In all cases, the species grown in the tannery soils were tolerant to a wide range of prevailing conditions. All of the bamboo species in the present study had a 100% survival rate in the tannery soils, except for D. birmanicus, which had a survival rate of 83.3%. Moreover, growth performance of the species in the tannery and control soils as evaluated by height and clump diameters did not vary significantly (P > 0.05). However, Cr levels in the tannery differed significantly (P < 0.05) among the species and rhizosphere soils. D. asper, B. vulgaris, D. membranaceus and B. blumeana had a bio-concentration factor (BCF) > 1 and translocation factor (TF) < 1, indicating that they are suitable for phytostablization. On the contrary, B. bambos had a bioaccumulation factor (BAF) < 1 and TF > 1, indicating potential for phytoextraction, while D. birmanicus showed no potential for phytoextraction or phytostabilization. Conclusions. The present study identified D. asper, B. vulgaris, D. membranaceus and B. blumeana as suitable for restoration of Cr-contaminated tannery sites. Close monitoring of toxic metals is necessary during application of these species. Further studies are also recommended using a wide variety of bamboo species to optimize their application in phytoremediation.