Environmental health in minority and other underserved populations: Benign methods for identifying lead hazards at day care centres of New Orleans

This study tests the hypothesis that exterior sources of lead dust are more important than interior sources in the route of exposure of children. Benign field methods were used to distinguish between potential and actual lead exposure problems. Utilising hand wipe and surface wipe techniques, hand and environmental samples were obtained from selected day care centres at different locations within New Orleans. Previous research has shown that soil lead is determined by location within the city. Private and public day care centres were selected from inner and outer city areas to estimate the extent of hand lead exposure. To measure and identify the extent of environmental lead exposure, hand wipes were taken before and after playing outdoors. Results of preliminary findings show that outdoor lead dust is a more potent contaminant of hands than indoor lead dust. An association was found between the amount of lead on children's hands after playing outdoors and the lead content in the exterior dust and soil. Although two girls out of forty children had exceptionally high hand lead quantities after playing outdoors, in general, boys have higher hand lead levels than girls. The private inner-city day care centre had a severe contamination problem in its outdoor play area. By contrast, the outdoor play area of the public inner city day care centre is of such a high quality that the quantity of lead dust is independent of location in the city.     

Urban soil-lead (Pb) footprint: retrospective comparison of public and private properties in New Orleans

Lead (Pb) is a toxin that after childhood exposure poses a lifetime of health risks. One route of exposure is soil-Pb as a result of ∼12 million metric tons of Pb residue in paint and gasoline sold in the US during the 20th Century. Pb accumulated in soil of the community is a good predictor for blood Pb of children living there. This retrospective study compares the soil-Pb on Housing Authority of New Orleans (HANO) properties with adjacent private residential (RES) properties within a 0.8 km (0.5 mile) radius. The sample subset (n = 951) is from two soil-Pb surveys (total n = 9,493) conducted between 1989 and 2000. The properties were in both the inner city (CORE) and outlying (OUTER) communities. The data were analyzed using multi-response permutation procedures (MRPP). The soil-Pb results differ significantly (P-value < 0.001) on same-aged HANO properties at different locations; thus, year of construction does not give adequate explanation for the soil-Pb differences. HANO and RES soils are significantly more Pb contaminated in the CORE than in OUTER communities (P-value < 0.001). The CORE has many more years of traffic congestion than OUTER communities; therefore, the lead additives to gasoline, and not lead-based paint, best elucidate the differences of the soil-Pb footprint at HANO and RES properties in the CORE and OUTER communites. Currently HANO properties are being redeveloped with cleaner soil, but soil on RES properties in the CORE of New Orleans remains a large source of Pb (median = 707 mg/kg in this study) for human exposure, especially children.     

Transport and dynamics of toxic pollutants in the natural environment and their effect on human health: research gaps and challenge

The source–pathway–receptor (SPR) approach to human exposure and risk assessment contains considerable uncertainty when using the refined modelling approaches to pollutant transport and dispersal, not least in how compounds of concern might be prioritised, proxy or indicator substances identified and the basic environmental and toxicological data collected. The impact of external environmental variables, urban systems and lifestyle is still poorly understood. This determines exposure of individuals and there are a number of methods being developed to provide more reliable spatial assessments. Within the human body, the dynamics of pollutants and effects on target organs from diffuse, transient sources of exposure sets ambitious challenges for traditional risk assessment approaches. Considerable potential exists in the application of, e.g. physiologically based pharmacokinetic (PBPK) models. The reduction in uncertainties associated with the effects of contaminants on humans, transport and dynamics influencing exposure, implications of adult versus child exposure and lifestyle and the development of realistic toxicological and exposure data are all highlighted as urgent research needs. The potential to integrate environmental with toxicological models provides the next phase of research opportunity and should be used to drive empirical and model assessments.     

Merthyr Mawr: a case study for the assessment of nitrate at humid dunes in England and Wales

Humid dunes in the UK are at risk from nutrient pressures from multiple sources. The Water Framework Directive 2000/60/EC (WFD) requires assessment and identification of these pressures with appropriate measures defined to mitigate against further damage. We discuss the application of nitrate threshold values for the WFD classification, illustrating this with a case study at Merthyr Mawr, South Wales, where ephemeral groundwater discharge from a spring (‘Burrows Well’) sourced within the Carboniferous Limestone, creates a large dune slack. Ecological surveys suggest that the vegetation in this slack was in unfavourable condition, due to high levels of nitrate. Applying the source-pathway-receptor model an investigation was undertaken to improve the conceptual model and assess the significance of damage from groundwater derived nutrients. Results show groundwater nitrate concentrations?~?10 mg/l as NO₃-N feeding the main slack waters. The vegetation survey data shows clear evidence of ecological damage, and the hydrogeological data traces the source of this back to the Carboniferous Limestone aquifer and not the overlying blown sands. Discharging groundwater is the source of the enrichment. Isotopic analysis suggests that the N is derived from inorganic fertilizer and/or atmospheric N. During the first cycle WFD characterisation the unfavourable status of the dunes due to chemical groundwater pressure resulted in a failure of the surrounding groundwater body, which was designated as poor status. The site has been re assessed for the 2nd Cycle WFD characterisation where recently developed nitrate ‘threshold’ values have been applied to assess the significance of damage for groundwater derived nutrients. The surrounding Carboniferous Limestone catchment is complex and could not be sufficiently constrained, thus land management changes could not be targeted. The paucity of historical or repeat vegetation surveys limits our ability to measure change within the dune vegetation and causes difficulties in understanding the impact of multiple pressures.     

Use of biomarkers in zooplankton for assessment of the 'health status' of marine and brackish environments: a short overview

The biomarker approach has been used for 25 years to study the environmental quality of marine, brackish and freshwater ecosystems. Biomarkers may indicate health status and can be applied to organisms of all zoological phyla by destructive or non destructive methods. For 5 years we have been using this approach in zooplankton to detect ecotoxicological alterations at low levels of the food chain due to contaminants. Here we review our approach to validate and apply biomarker techniques in zooplankton. We discuss advantages, limitations, some results and future research. We indicate that biomarkers in zooplankton can be used as new indices of trophic status and ecological integrity of Italian marine coastal and lagoon environments, to be included among the tools specified by Italian law D.Lgs. 152/2006.     

Instream and offstream environmental conditions and stream biotic integrity: Importance of scale and site similarities for learning and prediction

Two different methods to predict biotic integrity were tested and compared in the present paper. The first one tries to predict the fish indices of biotic integrity (IBI) at the state or regional scale based on the most similar observations to a specific target site of interest using the simple to implement k-nearest neighbors (or kNN) method. Two different distance functions were considered to find the k-nearest neighbors: the Euclidean and the Mahalanobis. The second method was applied on the same datasets and consisted of a step-wise multiple regression. The two modeling approaches yielded similar results but kNN proved to be more time-efficient and very fast computationally for the given dataset sizes, which allowed applying a leave-one-out cross validation.In an attempt to reveal the importance of scale in the prediction of IBI, regression models were constructed at the state (or regional) scale and at the more refined cluster of sampling sites scale. Clusters of sites were extracted using Kohonen's self-organizing maps (SOM) followed by k-means clustering of the SOM neurons. Cluster-level regression models, constructed after site patterning, performed better in IBI prediction than global regression models constructed without any previous site patterning. The importance of identifying groups of sites with similar environmental characteristics affecting the IBI was revealed. The combined use of site patterning and regression modeling for IBI prediction also helped identifying important variables acting at the local scale which remain latent at the global scale.     

Valuation of cancer and microbial disease risk reductions in municipal drinking water: An analysis of risk context using multiple valuation methods

We examine the value of health risk reductions (microbial illnesses/deaths and bladder cancer illnesses/deaths) in the context of drinking water quality treatment by public systems. When we assume that combined mortality and morbidity risk reductions are equally spread in the future; our results suggest that microbial risk-reduction programs have higher value than cancer risk-reduction programs, but that mortality risk reduction values are not significantly different for cancer and microbials. However, when a 25-year cancer latency is accounted for and a 5% discount rate is used, the value of cancer mortality risk reductions exceeds the value for microbial risk reductions. We also address a number of methodological issues, including performance of alternative choice experiment estimation (CE) techniques, relationship of CE to contingent valuation results, and implications for incorporating morbidity and mortality endpoints in the same survey instrument.     

Heavy Metals in Moss and Bark From Urban Area of Florence: A New Cleaness Procedure for Removing Superficial Particulate Matter

Hypnum cupressiforme epiphytic moss and tree bark (elm and holm oak) samples have been collected in three sites of the city of Florence in the period 1995-1998. Lead, zinc, copper, and cadmium were determined by differential pulse anodic stripping voltammetry (DPASV) in about 200 samples collected at different heights above ground. A new clean-up procedure by nitrogen jet has been followed and its efficiency has been also verified by electron microscopy (SEM and ESEM techniques). Lead median contents in moss and bark samples fall within the ranges of 0.052-0.86 and 0.20-1.30 μmoles g^-1 (dry weight), resulting values for moss and bark are proportional to the vehicular traffic density. the increasing use of lead-free gasoline has not been followed by a decrease of lead moss concentration.     

Heavy Metals in Moss and Bark From Urban Area of Florence: A New Cleaness Procedure for Removing Superficial Particulate Matter

Abstract

Hypnum cupressiforme epiphytic moss and tree bark (elm and holm oak) samples have been collected in three sites of the city of Florence in the period 1995–1998. Lead, zinc, copper, and cadmium were determined by differential pulse anodic stripping voltammetry (DPASV) in about 200 samples collected at different heights above ground. A new clean-up procedure by nitrogen jet has been followed and its efficiency has been also verified by electron microscopy (SEM and ESEM techniques). Lead median contents in moss and bark samples fall within the ranges of 0.052–0.86 and 0.20–1.30 μmoles g^?1 (dry weight), resulting values for moss and bark are proportional to the vehicular traffic density. the increasing use of lead-free gasoline has not been followed by a decrease of lead moss concentration.     

The influences of climate and hydrology on population dynamics of waterbirds in the lower Murrumbidgee River floodplains in Southeast Australia: Implications for environmental water management

Restoration of waterbird diversity and abundance is a key objective of river system management in Australia. Therefore, understanding the effects of climatic and hydrological variables on waterbird population dynamics is fundamental for successful river restoration programs. We investigated the population dynamics of waterbirds (total abundance) and seven functional waterbird groups in the floodplains of lower Murrumbidgee River. We found a general declining abundance trend from 1983 to 2007, except for the deep water foragers. We modelled the relative contribution of the climatic and hydrological factors to waterbird population decrease using the generalized additive model (GAM) framework after identifying the negative binomial distribution. Most of the seven functional groups were positively related to both annual rainfall and water usage, defined as the total water volume intercepted by the river reach, and the models indicated that rainfall was slightly more important. Temperature also played a role in waterbird abundance: the maximum summer temperature negatively influenced the abundance of dabbling ducks, shoreline foragers and fish eaters, while the minimum winter temperature positively affected the abundance of dabbling ducks and shoreline foragers. Overall, our results support the practice of providing environmental water for sustaining waterbird populations. However, environmental water provision is likely to be most effective when timed to coincide with antecedent rainfall.     

Environmental and health impacts of geochemical cycles of persistent toxic substances in food productions systems: Editorial to the special issue for the 8th International Conference on Geochemistry in the Topics & Sub-tropics (GeoTrop 2017)

Environmental Geochemistry and Health -     

Chromium in intertidal sediments of the Clyde,UK: potential for remobilisation and bioaccumulation

Detailed surveys of intertidal sediments have been performed along the north and south shores of the Inner Clyde estuary, UK. Surface sediment data reveal significant spatial variation in Cr content and an association with major sediment characteristics and location within the estuary. Depth variation for Cr and other heavy metals cannot be explained by variation in major geochemical controls such as grain size and organic matter and highlights the impact of historical contamination on sediment quality. These elevated levels at depth may still have environmental impact through redox-reactivity, in association with iron and manganese. Sequential extraction of sediments and pore water analysis of Cr(VI) and Cr(III) provide detailed information on release potential from the sediments. The implication of Cr mobility for biota in the estuary has been assessed by the analysis of a common marine bivalve, Mytilus edulis (Blue Mussel) and a burrowing polychaete, Nereis diversicolor (rag worm) from a number of survey sites. Bioconcentration factors for Mytilus indicate that the weakly held portion of sediment Cr is available for uptake and in the case of Nereis, bioaccumulation appears to be inhibited by sediment organic matter.