Forest filter effect for polybrominated diphenyl ethers in a tropical watershed.

There is limited research characterizing the fates of persistent organic pollutants in tropical multi-use watersheds. This study aimed to evaluate the role of forests in the environmental fates of select polybrominated diphenyl ethers (PBDEs) for a case study tropical drainage basin, the Rio Cobre watershed. Field samples of deposition, soil, litterfall and the atmosphere of a forest and nearby clearing were analyzed for the presence of the PBDEs (PBDE-28, 47, 99, 100, 153, 154, 183 and 209), which are routinely detected in the environment. The mean air and litterfall concentrations of these PBDEs were generally lower in the forest than in the clearing, whereas the deposition flux rate and soil concentrations were higher in the forest. The results suggest that the forest filtered the PBDEs by transferring them from the atmosphere to the soil, despite the tropical nature of the study site.

Bridging the Under-Five Mortality Gap for Africa in the Era of Sustainable Development Goals: An Ordinary Least Squares (OLS) Analysis.

BACKGROUND: While Africa achieved significant progress in reducing under-five mortality rate (U5MR) in the MDGs era, it did not achieve the set target and still has the highest average of 81 deaths per 1000 live births compared to a global average of 43 deaths. The SDG number 3 has set a new target of reducing U5MR to 25 deaths per 1000 births in the world, which serves a huge challenge, especially for Africa. Socioeconomic inequities that remain unaddressed across countries account for Africa's high U5MR. Unless there is adequate prioritization of important socioeconomic, healthcare, and environmental factors, the new SDGs target will be hindered. Objectives: In this study, our primary objective was to analyse and assess factors that account most for the U5MR inequities between Africa and the rest of the world. Methods: We conducted a series of ordinary least squares (OLS) regression-based prioritization analysis of socioeconomic, healthcare, and environmental variables from 43 African countries in a pool of 109 countries from around the world to understand the most important factors that account most for the high U5MR in Africa. FINDINGS: The results suggest that the most critical category for bridging the U5MR gap with the rest of the world is improved healthcare access. However, with all categories examined together, the OLS regression showed that the most important factors that accounted for Africa's high U5MR compared with the rest of the world were, in order: fertility rate, access to improved water, total health expenditure per capita, access to improved sanitation, and female employment rate. CONCLUSIONS: The findings reveal that Africa will significantly benefit from interventions geared towards both the treatment and prevention of acute infectious diseases in the form of providing affordable maternal healthcare services, as well as providing access to improved drinking water and sanitation.

Levels of PAHs in the waters, sediments, and shrimps of Estero de Urias, an estuary in Mexico, and their toxicological effects.

PAHs were measured in water, sediment, and shrimps of Estero de Urias, an estuary in Sinaloa, Mexico, during the rainy and dry seasons, and analyzed for eleven PAHs routinely detected in samples. Phenanthrene was the most dominant congener in the water, sediment, and shrimp samples comprising about 38, 24, and 25%, respectively, of the eleven PAHs detected, followed by pyrene and naphthalene in water and sediment samples, and pyrene and fluorine in the shrimp samples. Total PAH concentrations ranged from 9 to 347 ng/L in water, 27 to 418 ng/g in sediments, and 36 to 498 ng/g in shrimps. The sources of contamination are closely related to human activities such as domestic and industrial discharge, automobile exhausts, and street runoff. High concentrations were also measured during the rainy season and during the first quarter of the year. Toxicity tests were also carried out, exposing fish embryos and juvenile shrimps to some of these PAHs. Fish embryos exposed to PAHs showed exogastrulation, while juvenile shrimps showed significantly lower growth rates than controls. DNA and protein alterations were also observed. These toxicity tests indicate that PAH concentrations measured could be dangerous to some aquatic organisms, particularly during early stages of development.

A review of endosulfan, dichlorvos, diazinon, and diuron--pesticides used in Jamaica.

The global agricultural sector is the primary user of pesticides, consuming more than three billion kilograms of pesticides annually. Although pesticides are beneficial in controlling the proliferation of pests, they have been associated with adverse human and ecological impacts. Approximately 87% of the annually imported pesticides in Jamaica are applied within agricultural or household settings. However, in Jamaica, the potential impact on humans, their property, and the environment is unknown, as the fate of many of the locally applied pesticides has not been established. This review discusses four pesticides extensively applied in agricultural practices in Jamaica - endosulfan, diazinon, diuron, and dichlorvos. The information presented is essential for the development of fate and transport models of these chemicals. Consequently, health and ecological impact assessments may be conducted from the generated models.

Effectiveness of a federal healthy start program in reducing the impact of particulate air pollutants on feto-infant morbidity outcomes.

We sought to assess (1) the relationship between air particulate pollutants and feto-infant morbidity outcomes and (2) the impact of a Federal Healthy Start program on this relationship. This is a retrospective cohort study using de-identified hospital discharge information linked to vital records, and air pollution data from 2000 through 2007 for the zip codes served by the Central Hillsborough Federal Healthy Start Project in Tampa, Florida. Mathematical modeling was employed to compute minimal Euclidean distances to capture exposure to ambient air particulate matter. The outcomes of interest were low birth weight (LBW), very low birth weight (VLBW), small for gestational age, preterm (PTB), and very preterm birth. We used odds ratios to approximate relative risks. A total of 12,356 live births were analyzed. Overall, women exposed to air particulate pollutants were at elevated risk for LBW (AOR = 1.24; 95% CI = 1.07-1.43), VLBW (AOR = 1.58; 95% CI = 1.09-2.29) and PTB (AOR = 1.18; 95% CI = 1.03-1.34). Analysis by race/ethnicity revealed that the adverse effects of air particulate pollutants were most profound among black infants. Infants of women who received services provided by the Central Hillsborough Federal Healthy Start Project experienced improved feto-infant morbidity outcomes despite exposure to air particulate pollutants. Environmental air pollutants represent important risk factors for adverse birth outcomes, particularly among black women. Multi-level interventional approaches implemented by the Central Hillsborough Federal Healthy Start were found to be associated with reduced likelihood for feto-infant morbidities triggered by exposure to ambient air particulate pollutants.

Polybrominated diphenyl ethers (PBDEs) in soils along a rural-urban-rural transect: sources, concentration gradients, and profiles.

This study reports concentrations of PBDEs in surface soil samples collected along a 140 km transect across Kuwait to assess the role of urban centers as sources of persistent organic pollutants to the surrounding environment. The ΣPBDE concentrations varied by a factor of ~250 and ranged from 289 to 80,078 pgg (-1)d.w. The concentrations of PBDEs in Kuwait City were significantly higher (p<0.01) than those collected from sites outside the city supporting the hypothesis that urban centers are sources of PBDEs. The congener profiles were dominated by BDE-209, accounting for 93% of the PBDEs in the soil samples. The concentrations of all congeners (except BDE-209) were highly correlated with percent organic carbon (%OC) (p>0.05) when the data from Kuwait City was omitted from the analysis. These findings suggest that soil concentrations outside the urban centers were close to equilibrium with the atmosphere.

Evidence for major emissions of PCBs in the west African region.

In previous studies unexpectedly high air concentrations of polychlorinated biphenyls (PCBs) were observed in ship-based measurements made ∼400 km off parts of the West African coast. To investigate further (i) samples were taken on board the RV Polarstern during a cruise from Germany to South Africa in October-November 2007; (ii) samples were obtained on Cape Verde Island during the same period to monitor airflows from Africa; and (iii) passive samplers were deployed in four West African countries to try to characterize potential sources on land. Results were as follows: on Cape Verde and on the ship air masses came predominantly (∼ 95%) from the African continent; the shipboard Σ29PCB concentrations off West Africa ranged from 10 to 360 pg m(-3) and from 6 to 99 pg m(-3) in Cape Verde; the highest land-based concentrations were observed in Ivory Coast and the Gambia (up to 300 pg m(-3)) and the lowest was observed in Ghana (9 pg m(-3)). Taken together, these and previous studies indicate there are more major emission(s) of PCBs and different source types in parts of West Africa than accounted for in current global atmospheric emissions estimates. Results from the FLEXPART model and PAH measurements show that emission inventories and biomass burning cannot fully explain the high PCB concentrations. Potential sources of the high PCB levels to the African regions are discussed, namely illegal dumping of PCB containing waste with release via volatilization and uncontrolled burning, and the storage and breakup of old ships.

Polybrominated diphenyl ethers in three commercially important fish from the northwestern Arabian Gulf: occurrence, concentration, and profiles.

Polybrominated diphenyl ethers (PBDEs) were measured in three species of fish (yellowfin seabream [Acanthopagrus latus, a predatory fish]; Klunzinger's mullet [Liza klunzingeri, a pelagic fish]; and large-scaled tonguesole [Cynoglossus arel, a demersal fish]) collected from two sites in the northwestern part of the Arabian Gulf, a marginal sea of the tropical Indo-Pacific Ocean. Concentrations of ΣPBDEs ranged from 11 to 57 ng g(-1) lipid weight (lw) for mullet, 5.0-38 ng g(-1) lw for tonguesole, and 2.8-48 ng g(-1) lw for seabream in Kuwait Bay, whereas in the open gulf, concentrations ranged from 6.0 to 160 lw for mullet, 8.3-190 lw for tonguesole, and 7.1-62 for lw for seabream. The congener composition in all species from both sites was dominated by BDEs 47, 99, and 100, which together constituted approximately 90% of the congeners detected. Although no statistically significant intersite differences were found, ΣPBDEs concentrations in mullet were significantly higher than those in seabream (p = 0.01). However, no significant differences existed between mullet and tonguesole (p = 0.28) or between tonguesole and seabream (p = 0.06). ΣPBDE concentrations were negatively correlated with fish mass for all species; however, the correlations were statistically insignificant, suggesting a growth dilution effect.

Diurnal fluctuations in polybrominated diphenyl ether concentrations during and after a severe dust storm episode in Kuwait City, Kuwait.

Concentrations of polybrominated diphenyl ethers (PBDEs) were quantified in four-hour integrated air samples obtained serially over a five day period in May 2007 in Kuwait City during and after a severe dust storm. The ∑PBDE concentrations ranged from 51 to 1307 pg m(-3) for the first two days of sampling and 20 to 148 pg m(-3) for the rest of the sampling period. The first two days of sampling occurred during a severe dust storm episode when the total suspended particulates (TSP) in air exceeded 1000 µg/m(3) with concentrations peaking during the day and decreasing at night. During this dust episode, the peak nighttime PBDE concentration was 30 times higher than the minimum daytime concentration. Although ∑PBDE concentrations peaked at night during the first two sampling days, the fluctuations in the BDE 47:99 ratio tracked changes in ambient temperature remarkably well, following a clear diurnal pattern. The fraction of congeners in the gas phase varied inversely with solar flux and was lower on days with a high number of hours of sunshine, suggesting that photolytic degradation of gas-phase PBDEs was occurring.

PAHs in background soils from Western Europe: influence of atmospheric deposition and soil organic matter.

The levels and distribution of polynuclear aromatic hydrocarbons (PAHs) were determined in soil samples from background locations in the UK and Norway, to investigate their spatial distribution and the controlling environmental factors. Concentrations ranged between 42 and 11200 microg kg(-1) (geometric mean 640 microg kg(-1)) and 8.6 and 1050 microg kg(-1) (150 microg kg(-1)) dry weight in the UK and Norwegian soil, respectively. Proximity to sources and locations susceptible to high atmospheric depositional inputs resulted in higher concentrations. Statistically significant relationships were observed between PAH and total organic carbon (TOC) in the Norwegian samples. High molecular weight PAHs correlated with black carbon (BC) in UK-woodland soil. These observations support the hypothesis that TOC plays an important role in the retention of PAHs in soil and that PAHs are often combined with BC during combustion emissions. PAHs with 4 and more rings comprised approximately 90% of total PAHs in the UK soil, but only 50% in the Norwegian soil. The mixture of PAHs implied that fractionation occurred during long-range atmospheric transport and deposition. The lighter PAHs with lower K(ow) values more readily reached the most remote sites. The heavier PAHs with higher K(ow) values remained in closer proximity to sources.

Passive air sampling of polychlorinated biphenyls, organochlorine compounds, and polybrominated diphenyl ethers across Asia.

Asia is of global importance economically, yet data on ambient persistent organic pollutant levels are still sparse for the region, despite international efforts under the Stockholm Convention to identify and reduce emissions. A large-scale passive air sampling survey was therefore conducted in Asia, specifically in China, Japan, South Korea, and Singapore. Polyurethane foam disks were deployed simultaneously at 77 sites, between Sept 21 and Nov 16, 2004, and analyzed for polychlorinated biphenyls (PCBs), organochlorine compounds (hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), chlordane), and polybrominated diphenyl ethers (PBDEs). The meteorological conditions prevailing in the region at this time facilitated the assessment of local/regional differences in atmospheric emissions, because large-scale advection effects due to monsoons or dust storms did not occur. Air concentrations estimated assuming an average sampler uptake rate of 3.5 m3/day ranged as follows (pg m(-3)): PCBs, 5-340; HCB, 10-460; DDTs, 0.4-1800; chlordanes, 1-660; PBDEs, < 0.13-340. South Korea and Singapore generally had regionally low concentrations. Elevated concentrations of PCBs, DDTs, and HCB occurred at sites in China, higher than reported in a similar recent sampling campaign in Europe. Chlordane was highest in samples from Japan (which also had elevated levels of PCBs and DDTs) and was also elevated in some Chinese locations. PBDE levels were generally low in the region.

PCBs and selected organochlorine compounds in Italian mountain air: the influence of altitude and forest ecosystem type.

Passive air samplers (polyurethane foam disks) were deployed on an altitudinal transect in the rural Italian Alps to investigate the potential influence of forest cover on air concentrations. Samplers were exposed overtwo periods, each of several weeks, either in clearings or in forests. In the first period, there was high leaf coverage (high leaf area index, LAI); in the second, the LAI was low after the autumnal leaf fall. PCBs sequestered in the PUF generally declined with altitude, for example, in the clearings PCBs-28, 52, 90/101, 118, and 138, all showed statistically significant declines (p < 0.05). The mass of HCB sequestered increased with altitude, evidence of cold condensation. Ratios of the forest:clearing concentrations were calculated; this ratio expresses the filtering ability of forests to deplete air concentrations compared to the adjacent clearings. During the high LAI sampling period, these depletion factors ranged between 0.93 and 0.54 and were inversely correlated with temperature-corrected log K0A. This relationship was notobserved during the low LAI sampling period. The depletion factors were normalized using the LAI to give a density independent depletion factor (DIDF). The slopes of the correlations with K0A were comparable for broadleaf or coniferous forests at different altitudes, suggesting that leaf surfaces determine the exchanges with air. Broadleaf forests at 1000 and 1400 m showed similar behavior, while a conifer forest at 1800 m gave depletion factors which were higher by about a factor of 2. It is suggested that DIDF can be used in regional environmental fate models to estimate the contribution of forests to contaminant fate.

Atmospheric dry deposition of persistent organic pollutants to the Atlantic and inferences for the global oceans.

Atmospheric deposition to the oceans is a key process affecting the global dynamics and sinks of persistent organic pollutants (POPs). A new methodology that combines aerosol remote sensing measurements with measured POP aerosol-phase concentrations is presented to derive dry particulate depositional fluxes of POPs to the oceans. These fluxes are compared with those due to diffusive air-water exchange. For all polychlorinated biphenyl (PCB) congeners and lower chlorinated dibenzo-p-dioxins and furans (PCDD/Fs), air-water exchange dominates the dry deposition mechanism. However, this tendency reverses in some areas, such as in marine aerosol influenced areas and dust outflow regions, consistent with the important variability encountered for the depositional fluxes. Seasonal variability is mainly found in mid-high latitudes, due to the important influence of wind speed enhancing dry deposition fluxes and temperature as a driver of the gas-particle partitioning of POPs. The average dry aerosol deposition flux of sigmaPCBs and sigmaPCDD/Fs to the Atlantic Ocean is calculated to be in the order of 66 ng m(-2) yr(-1) and 9 ng m(-2)yr(-1) respectively. The total dry aerosol deposition of sigmaPCBs and sigmaPCDD/Fs to the Atlantic Ocean is estimated to be 2200 kg yr(-1) and 500 kg yr(-1), respectively, while the net air-water exchange is higher, 22000 kg sigmaPCBs yr(-1) for PCBs and 1300 kg sigmaPCDD/Fs yr(-1). Furthermore, it is suggested that marine aerosol plays an important role in scavenging atmospheric contaminants.

Passive air sampling of polycyclic aromatic hydrocarbons and polychlorinated naphthalenes across Europe.

This study presents concurrently sampled ambient air data for a range of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated naphthalenes (PCNs) at the continental scale. This was achieved with a passive air sampling system, by deploying polyurethane foam disks, which were prepared in one laboratory, sealed to prevent contamination, sent out by courier to volunteers participating in different countries, exposed for six weeks, collected, resealed, and returned to the laboratory for analysis. The study area was Europe, a region with a history of extensive persistent organic pollutants usage and emission, and with marked national differences in population density, the degree of urbanization and industrial and agricultural development. Samplers were deployed at remote, rural, and urban locations in 22 countries. Calculated air concentrations were broadly in line with those obtained by conventional active air sampling techniques, for both compound classes and for compounds existing predominantly in the gas and particle phases. The geographical compound distribution reflected suspected regional emission patterns and highlighted localized source areas. Both PAH and PCN levels varied by more than two orders of magnitude. The implications for sources are discussed.

Potential contamination of shipboard air samples by diffusive emissions of PCBs and other organic pollutants: implications and solutions.

Air samples were taken onboard the RRS Bransfield on an Atlantic cruise from the United Kingdom to Halley, Antarctica, from October to December 1998, with the aim of establishing PCB oceanic background air concentrations and assessing their latitudinal distribution. Great care was taken to minimize pre- and post-collection contamination of the samples, which was validated through stringent QA/QC procedures. However, there is evidence that onboard contamination of the air samples occurred,following insidious, diffusive emissions on the ship. Other data (for PCBs and other persistent organic pollutants (POPs)) and examples of shipboard contamination are presented. The implications of these findings for past and future studies of global POPs distribution are discussed. Recommendations are made to help critically appraise and minimize the problems of insidious/diffusive shipboard contamination.

Spatial distribution of atmospheric PAHs and PCNs along a north-south Atlantic transect.

Ship-board air samples collected between The Netherlands and South Africa in January-February 2001 were analysed for polycyclic aromatic hydrocarbons (PAHs) and polychlorinated naphthalenes (PCNs). The highest PAH concentrations occurred in the European samples, and in samples close to West Africa and South Africa. Consistently low PAH concentrations were measured in the southern hemisphere open ocean samples (190-680 pg/m3). The highest PCN concentrations occurred in the European samples, but high values were also detected off the West African coast, and in the sample taken closest to South Africa. Data are presented for diurnal cycles taken in the remote South Atlantic. The day:night ratios of phenanthrene, 1-methylphenanthrene and fluoranthene were typically approximately 1.5-2.5:1. The mechanism(s) causing this observation is/are not understood at present, but dynamic environmental process(es) is/are implicated.

Further studies on the latitudinal and temporal trends of persistent organic pollutants in Norwegian and U.K. background air.

Data are presented for PBDEs, PCBs, and selected organochlorine compounds, measured at background locations by passive air samplers (semipermeable membrane devices, SPMDs) along a latitudinal transect from the south of the U.K. to the north of Norway during 2000-2002. This work is part of an ongoing air sampling campaign in which PCB data were previously obtained in 1994-1996 and 1998-2000. Comparisons of the masses of chemicals sequestered by the SPMDs during these different time intervals are used to investigate spatial and temporal trends. The study yielded examples of compounds that increase, decrease, or remain uniform with latitude, suggestive of differences in the relative importance of deposition versus atmospheric reaction in controlling their long-range atmospheric transport potential. The main constituents of the penta-BDE product were detected at amounts equivalent to 2.0 (range 1.1-2.5) and 1.1 (0.8-1.6) pg m(-3) for the U.K. and Norway background sites, respectively. Fractionation of PBDEs was observed, because the amounts of lighter BDEs decreased with latitude, while the heavier molecular weight congeners were quite uniformly distributed. In contrast, the sequestered amounts of the lighter PCBs were uniformly distributed with latitude, with heavier PCBs decreasing. Sequestered amounts of hexachlorobenzene increased with latitude. Preliminary PCB atmospheric clearance rates were derived using the 1994-1996, 1998-2000, and 2000-2002 data. They averaged ca. 3.5 years for all congeners/locations. No systematic differences in congeners or locations were noted, supporting the hypothesis that the underlying trends in European background air are still controlled by primary, rather than secondary, sources.

Evidence for dynamic air-water coupling and cycling of persistent organic pollutants over the open Atlantic Ocean.

Ship-board air samples collected between The Netherlands and South Africa in January-February 2001 were analyzed for PCBs and selected organochlorine compounds. Broad latitudinal trends in compound concentrations were influenced by proximity to source areas, land, and air mass origin. Lowest concentrations were observed in the remote south Atlantic (1-32 degrees S), where sigma7PCB concentrations were approximately 10 pg m(-3). Here, a diurnal cycle was noted for some PCB congeners, with the daytime concentrations higher than the nighttime concentrations, typically by a factor of 1.5-2.5. The data are consistent with a close coupling of air-open ocean concentrations, which has important implications for future rates of POP removal from the global "recyclable pool". The observations are discussed in the context of the potential controlling variables. Interactions between the phytoplankton and the dissolved phase are implicated in controlling the observations made here and a hypothesis to explain the cycling trends is presented. However, the precise mechanisms remain unclear; further studies are urgently required to elucidate them.

Passive air sampling of PCBs, PBDEs, and organochlorine pesticides across Europe.

This study presents concurrently sampled ambient air data for a range of persistent organic pollutants at the continental scale. This was achieved using a passive air sampling system, deploying polyurethane foam disks, which was prepared in one laboratory, sealed to prevent contamination, sent out by courier to volunteers participating in different countries, exposed for 6 weeks, collected, resealed, and returned to the laboratory for analysis. Europe was the study area--a region with a history of extensive POPs usage and emission and with marked national differences in population density, the degree of urbanization and industrial/agricultural development. Samplers were deployed at remote/rural/urban locations in 22 countries and analyzed for PCBs, a range of organochlorine pesticides (HCB, alpha-HCH, gamma-HCH, ppDDT, ppDDE), and PBDEs. Calculated air concentrations were in line with those obtained by conventional active air sampling techniques. The geographical pattern of all compounds reflected suspected regional emission patterns and highlighted localized hotspots. PCB and PBDE levels varied by over 2 orders of magnitude; the highest values were detected in areas of high usage and were linked to urbanized areas. HCB was relatively uniformly distributed, reflecting its persistence and high degree of mixing in air. Higher gamma-HCH, ppDDT, and ppDDE levels generally occurred in South and East Europe.