A new challenge to child and adolescent survival in urban Africa: an increasing burden of road traffic injuries

OBJECTIVES: To develop an epidemiological profile and present the burden of urban road-traffic injuries (RTI) in children and adolescents in urban Sub-Saharan Africa. METHOD: A systematic review of published and gray literature of children and adolescents < or =19 years old involved in RTI in urban regions in Sub-Saharan Africa from January 1980-December 2003. RESULTS: The mean annual incidence for urban road-traffic injuries was 109.8 per 100,000 children, and males were twice as involved as their female counterparts. Children between 10 to 14 years constitute the most frequent group involved in road crashes (36%) while pedestrians represent an average of 68% of all childhood RTI cases. Twenty Healthy Life Years per 1,000 children and adolescents are being lost annually in the region from RTI. CONCLUSIONS: There is an urgent need to develop a regional health research agenda to generate an accurate estimate of the burden of road-traffic injuries on children. This is a new challenge for child health and there is a need to raise awareness among policy makers to promote appropriate interventions.     

Modeling post-fledging survival of Lark Buntings in response to ecological and biological factors

We evaluated the influences of several ecological, biological, and methodological factors on post-fledging survival of a shortgrass prairie bird, the Lark Bunting (Calamospiza melanocorys). We estimated daily post-fledging survival (n = 206, 82 broods) using radiotelemetry and color bands to track fledglings. Daily survival probabilities were best explained by drought intensity, time in season (quadratic trend), ages < or = 3 d post-fledging, and rank given drought intensity. Drought intensity had a strong negative effect on survival. Rank was an important predictor of fledgling survival only during the severe drought of 2002 when the smallest fledglings had lower survival. Recently fledged young (ages < or = 3 d post-fledging) undergoing the transition from nest to surrounding habitat experienced markedly lower survival, demonstrating the vulnerable nature of this time period. Survival was greater in mid and late season than early season, corresponding to our assumptions of food availability. Neither mark type nor sex of attending parent influenced survival. The model-averaged product of the 22-d survival calculated using mean rank and median value of time in season was 0.360 +/- 0.08 in 2001 and 0.276 +/- 0.08 in 2002. Survival estimates that account for age, condition of young, ecological conditions, and other factors are important for parameterization of realistic population models. Biologists using population growth models to elucidate mechanisms of population declines should attempt to estimate species-specific of post-fledging survival rather than use generalized estimates.     

Black carbon: the reverse of its dark side

The emission of black carbon is known to cause major environmental problems. Black carbon particles contribute to global warming, carry carcinogenic compounds and cause serious health risks. Here, we show another side of the coin. We review evidence that black carbon may strongly reduce the risk posed by organic contaminants in sediments and soils. Extremely efficient sorption to black carbon pulls highly toxic polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins, polybrominated diphenylethers and pesticides into sediments and soils. This increased sorption is general, but strongest for planar (most toxic) compounds at environmentally relevant, low aqueous concentrations. Black carbon generally comprises about 9% of total organic carbon in aquatic sediments (median value of 300 sediments), and then may reduce uptake in organisms by up to two orders of magnitude. This implies that current environmental risk assessment systems for these contaminants may be unnecessarily safe.     

Sorption of organic compounds to activated carbons. Evaluation of isotherm models

Sorption to ‘hard carbon’ (black carbon, coal, kerogen) in soils and sediments is of major importance for risk assessment of organic pollutants. We argue that activated carbon (AC) may be considered a model sorbent for hard carbon. Here, we evaluate six sorption models on a literature dataset for sorption of 12 compounds onto 12 ACs and one charcoal, at different temperatures (79 isotherms in total). A statistical analysis, accounting for differences in the number of fitting parameters, demonstrates that the dual Langmuir equation is in general superior and/or preferable to the single and triple Langmuir equation, the Freundlich equation, a Polanyi–Dubinin–Manes equation, and the Toth equation. Consequently, the analysis suggests the presence of two types of adsorption sites: a high-energy (HE) type of site and a low-energy (LE) type of site. Maximum adsorption capacities for the HE domain decreased with temperature while those for the LE domain increased. Average Gibbs free energies for adsorption from the hypothetical pure liquid state at 298 K were fairly constant at −15 ± 4 and −5 ± 4 kJ mol⁻¹ for the HE and LE domain, respectively.     

Distribution of organochlorine pesticides and heavy metal residues in fish and shellfish from Calicut region, Kerala, India

Fish collected from five different locations from the Calicut region, India were analysed for the levels of organochlorine pesticides (OCPs) and heavy metal (HM) residues in order to elucidate the status of these chemical contaminants in fish and shellfish meant for human consumption. The highest concentrations of OCPs detected in the edible portion of fish were 10.47, 70.57 and 28.35 ng g-1 wet weight, in marine, brackish water and freshwater, respectively. BHC and heptachlor epoxide formed the major share of OCPs in the marine fish while BHCs contributed to the major share in the freshwater and brackish water fish. The DDT (sum of DDT and its metabolites) ranged from 0.05 to 8 ng g-1 in the samples irrespective of the habitat. Among the HMs, Cu, Zn, Mn and Cr were present in the samples irrespective of the place of collection. About 22% of the samples from the freshwater area contained marginally higher lead content above the legal limit of 0.2-0.4 microg g-1. The Cr content ranged from 0.1 to 1.1 microg g-1 in the fish with marginally higher content in the fish from freshwater and marine regions (0.55-1.1 microg g-1). Mercury was detected in the samples (55%) from marine habitat only. The concentrations of OCPs and HMs in the samples, in general, were below the maximum residual level recommended by various organizations.     

A comparative assessment of heavy metal accumulation in soft parts and byssus of mussels from subarctic, temperate, subtropical and tropical marine environments

Existing data on metal concentrations in mussels from subarctic, temperate, subtropical and tropical waters were analyzed using multivariate statistics in order to assess regional variations in metal contamination. Potential errors were reduced by only analyzing data from surveys that employed the same protocols, analytical methodologies and analysts. Factor analysis demonstrated that mussels inhabiting extremely contaminated areas (e.g. from Japanese and Swedish metallurgy sources) could be separated from mussels from other contaminated areas, and that metals such as Cd, Pb, Cu and Zn could be used to identify heavily contaminated samples while Co, Fe, Cr and Ni concentrations were good markers for exposure to inputs from different industrial sources. Furthermore byssus, like soft tissue, selectively and sensitively reflects variations of certain metal concentrations in ambient waters and thus serves as a reliable biomonitor for these contaminants in a variety of coastal and estuarine areas.     

Arsenic residues in predatory birds from an area of Britain with naturally and anthropogenically elevated arsenic levels

Birds of prey forage over large areas and so might be expected to accumulate contaminants which are elevated but heterogeneously distributed in the general environment. The aim of this study was to test the hypothesis that arsenic levels in raptors from a region with elevated environmental arsenic concentrations were higher than those in birds from an uncontaminated part of Britain. Arsenic concentrations in the liver, kidney and muscle of kestrels, Falco tinnunculus, sparrowhawks, Accipiter nisus, and barn owls, Tyto alba, from south-west (SW) England, an area with naturally and anthropogenically (through mining) elevated environmental arsenic concentrations, were compared with those in birds from SW Scotland, where no such geochemical anomaly exists. Arsenic residues in kestrels from SW England were approximately three times greater than those in birds from SW Scotland for the three tissue types analysed. This was not the case for the other species in which arsenic residues were similar in birds from both regions. It is suggested that differences between species in both diet and arsenic metabolism could explain why kestrels have elevated arsenic tissue burdens in response to general environmental contamination but sparrowhawks and barn owls do not.     

PCB congener distributions in muscle,liver and gonad of Fundulus heteroclitus from the lower Hudson River Estuary and Newark Bay

Gradients in sediment polychlorinated biphenyl (PCB) concentrations and PCB congener profiles exist along the Hudson River (NY, USA). We evaluated site and tissue differences in PCB concentration and congener profiles in resident mummichog (Fundulus heteroclitus) collected from PCB-contaminated sites in the lower Hudson River and the New York/New Jersey Harbor Estuary. Fish were collected from three PCB-contaminated sites Piermont Marsh (P), Iona Marsh (I), and Newark Bay (NB), and from two reference sites (Flax Pond, NY; Succotash Salt Marsh, RI). Congener profiles were statistically analyzed using principal component analysis (PCA) and general linear model (GLM) profile analysis. Contaminated fish had PCB tissue concentrations approximately 10-fold higher than those of reference fish. There were no site differences in PCB body burden (all tissues combined) among the contaminated site fish. However, relative PCB concentration did differ between organs: NB fish (gonad=liver>muscle); I and P fish (gonad>liver>muscle). In contrast to PCB content, PCB congener profiles did show site differences; NB mummichog being depleted in the less chlorinated congeners relative to I and P fish, likely reflecting different PCB sources to these populations. Within a site, however, PCB congener patterns were similar between liver, gonad and muscle. In conclusion, PCA and GLM analyses gave complementary results, both analyses indicating differences in site, but not tissue, distributions of PCB congeners. This study also demonstrates that unlike congener profiles, total PCB content does differ dramatically amongst tissues and further, that PCB differences among tissues (gonad vs. liver vs. muscle) can vary with site.     

Water-soluble species and heavy metal contamination of the petroleum refinary area,Jordan

The levels of lead, cadmium, copper, zinc, aluminum, chromium, and iron in street dust, soil, and plants in the Jordanian petroleum refinery were determined using flame and graphite-furnace atomic absorption spectrophotometry. Major cations (Li+, Na+, NH4+, K+, Mg2+, and Ca2+) and anions (F-, Cl-, NO3-, SO4(2-), and Br-) were also determined using suppression mode ion chromatography. Generally, higher levels of the heavy metals studied were found in street dust samples than in soil samples. On the other hand, except Cl-, and Li+ ions, other anions and cations showed higher concentrations in soil than in street dust samples. For plant samples, unwashed samples showed higher levels of heavy metals than their washed counterparts, indicating that dust fall is a source of heavy metal contamination.     

Water Quality Assessment of Osun River: Studies on Inorganic Nutrients

The present investigation provides data of some ions, namely Na⁺, Ca²⁺, NH₄ ⁺,Cl^-, NO₃ ^-,CN^- and PO₄ ^3- on water samples of river Osun,selected rivers in the region and groundwaters. The pH,temperature, electrical conductivity (EC), total dissolvedsolids (TDS), total hardness (TH) and total carbon (IV) oxide(TCO₂) have also been determined to asses the chemicalstatus and pollution levels of these water sources. The highervalues of certain parameters with respect to the acceptablestandard limits for drinking water indicate the pollution inboth groundwater and river water samples of the study area, and make the waters unsuitable for various applications. Thehigh pollution river water source showed higher levels ofphosphate, nitrate and ammonium ions (P < 0.05). There is nosignificant difference (P < 0.05) between the meanconcentrations of other inorganic nutrients in the high and lowpollution water source types. The correlation coefficientbetween quality parameter pairs of river water and groundwatersamples are determined and the significance of these parametersin both types of water sources are discussed.