Characterization of organic chemical contaminants in sediments from Jobos Bay, Puerto Rico

Jobos Bay, located on the southeastern coast of Puerto Rico, contains a variety of habitats including mangroves, seagrass meadows, and coral reefs. The watershed surrounding the bay includes a number of towns, agricultural areas, and the Jobos Bay National Estuarine Research Reserve (NERR). Jobos Bay and the surrounding watershed are part of a Conservation Effects Assessment Project (CEAP), involving the Jobos Bay NERR, the US Department of Agriculture, and the National Oceanic and Atmospheric Administration (NOAA) to assess the benefits of agricultural best management practices (BMPs) on the terrestrial and marine environments. As part of the Jobos Bay CEAP, NOAA collected sediment samples in May 2008 to characterize over 130 organic chemical contaminants. This paper presents the results of the organic contaminant analysis. The organic contaminants detected in the sediments included polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and the pesticide DDT. PAHs at one site in the inner bay near a boat yard were significantly elevated; however, all organic contaminant classes measured were below NOAA sediment quality guidelines that would have indicated that impacts were likely. The results of this work provide an important baseline assessment of the marine environment that will assist in understanding the benefits of implementing BMPs on water quality in Jobos Bay.     

Upstream to downstream: stormwater quality in Mayagüez, Puerto Rico

The focus of this research was upon consequences of urban stormwater runoff entering two streams in Mayagüez, Puerto Rico. Mayagüez is the largest urban area of the western side of the island of Puerto Rico and provides an excellent point of reference to monitor the affects of urban development on water quality in a tropical climate. The two monitored streams were Quebrada del Oro and Cano Majagual. The research hypothesis asks, "Does stormwater runoff from urban development measurably affect the water quality of downstream receiving water by raising the conductivity, temperature, and flow quantity characteristics during storm events in comparison to upstream water quality?" In essence, the results for Quebrada del Oro agreed with the hypothesis of this project, while Cano Majagual produced results different from the hypothesis primarily due to the absence of non-urbanized land use for both upstream and downstream sections as well as the buffering capacity of a large wetland just upstream of the downstream instrument location of Cano Majagual. Both streams showed signs of stream impairment according to the temperature criteria (32°C or 90°F) set by the Junta de Calidad Ambiental and the US Environmental Protection Agency. Dissolved oxygen levels of the streams were severely affected by water temperature and oxygen-consuming matter within these stream systems, making dissolved oxygen and temperature important water quality parameters for tropical climates.     

Bio-monitoring for uranium using stream-side terrestrial plants and macrophytes

This study evaluated the abilities of various plant species to act as bio-monitors for environmental uranium (U) contamination. Vegetation and soil samples were collected from a U processing facility. The water-way fed from facility storm and processing effluents was the focal sample site as it represented a primary U transport mechanism. Soils and sediments from areas exposed to contamination possessed U concentrations that averaged 630 mg U kg(-1). Aquatic mosses proved to be exceptional accumulators of U with dry weight (dw) concentrations measuring as high as 12,500 mg U kg(-1) (approximately 1% of the dw mass was attributable to U). The macrophytes (Phragmites communis, Scripus fontinalis and Sagittaria latifolia) were also effective accumulators of U. In general, plant roots possessed higher concentrations of U than associated upper portions of plants. For terrestrial plants, the roots of Impatiens capensis had the highest observed levels of U accumulation (1030 mg kg(-1)), followed by the roots of Cyperus esculentus and Solidago speciosa. The concentration ratio (CR) characterized dry weight (dw) vegetative U levels relative to that in associated dw soil. The plant species that accumulated U at levels in excess of that found in the soil were: P. communis root (CR, 17.4), I. capensis root (CR, 3.1) and S. fontinalis whole plant (CR, 1.4). Seven of the highest ten CR values were found in the roots. Correlations with concentrations of other metals with U were performed, which revealed that U concentrations in the plant were strongly correlated with nickel (Ni) concentrations (correlation: 0.992; r-squared: 0.984). Uranium in plant tissue was also strongly correlated with strontium (Sr) (correlation: 0.948; r-squared: 0.899). Strontium is chemically and physically similar to calcium (Ca) and magnesium (Mg), which were also positively-correlated with U. The correlation with U and these plant nutrient minerals, including iron (Fe), suggests that active uptake mechanisms may influence plant U accumulation.     

Monitoring of ozone effects on the vitality and increment of Norway spruce and European beech in the Central European forests

The ozone effect on Norway spruce (Picea abies (L) Karst.) and European beech (Fagus sylvatica L.) was studied on 48 monitoring plots in 2005-2008. These plots represent two major forest tree species stands of different ages in eight regions of the Czech Republic. The forest conditions were represented by defoliation and the annual radial increment of individual trees. The ozone exposure was assessed by using modeled values of mean annual O(3) concentration and the AOT40 index. The malondialdehyde (MDA) content of the foliage was analysed and used as an indicator of oxidative stress. The correlation analysis showed a significant relation of Norway spruce defoliation to the AOT40 exposure index, and European beech defoliation to the MDA level. The radial increment response to ozone was significant only for the European beech: (a) the correlation analysis showed its decrease with increasing AOT40; (b) the regression model showed its decrease with increasing mean annual ozone concentration only at lower altitudes (<700 m a.s.l.).     

Fragmentation of extracellular DNA by long-term exposure to radiation from uranium in aquatic environments

Persistent harmful scenarios associated with disposal of radioactive waste, high-background radiation areas and severe nuclear accidents are of great concern regarding consequences to both human health and the environment. Of particular concern is the extracellular DNA in aquatic environments contaminated by radiological substances. Strand breaks induced by radiation promote decrease in the transformation efficiency for extracellular DNA. The focus of this study is the quantification of DNA damage following long-term exposure (over one year) to low doses of natural uranium (an alpha particle emitter) to simulate natural conditions, since nothing is known about alpha radiation induced damage to extracellular DNA. A high-resolution Atomic Force Microscope was used to evaluate DNA fragments. Double-stranded plasmid pBS as a model for extracellular DNA was exposed to different amounts of natural uranium. It was demonstrated that low concentrations of U in water (50 to 150 ppm) produce appreciable numbers of double strand breaks, scaling with the square of the average doses. The importance of these findings for environment monitoring of radiological pollution is addressed.     

Monitoring fish distributions along electrofishing segments

Electrofishing is widely used to monitor fish species composition and relative abundance in streams and lakes. According to standard protocols, multiple segments are selected in a body of water to monitor population relative abundance as the ratio of total catch to total sampling effort. The standard protocol provides an assessment of fish distribution at a macrohabitat scale among segments, but not within segments. An ancillary protocol was developed for assessing fish distribution at a finer scale within electrofishing segments. The ancillary protocol was used to estimate spacing, dispersion, and association of two species along shore segments in two local reservoirs. The added information provided by the ancillary protocol may be useful for assessing fish distribution relative to fish of the same species, to fish of different species, and to environmental or habitat characteristics.     

Relevance of the economic crisis in chemical PM10 changes in a semi-arid industrial environment

This paper shows the changes in PM(10) levels and chemical composition in a region in southeast Spain between two periods: September 2005-August 2006 and June 2008-May 2009. PM(10) levels in this arid region, with a great number of cement, ceramic and related industries, have decreased in the second period in concordance with the reduction of industrial production due to the economic crisis and the closure of a cement plant. Annual average levels of PM(10) decreased from 41?μg?m(-3) in 2005 to 30?μg?m(-3) in 2008 (27%) and to 23?μg?m(-3) in 2009 (23%). The relative contribution of the different sources has not changed in the area in the latter period and the elements with mineral origin are the main components of the PM(10) composition. There is a reduction in the concentration of the components that have soil-related industries and crustal material resuspension as their main sources, mainly in the case of CO(3) (2-), Ca, Sr, Tl and Pb, but the seasonal patterns were the same in both periods. As a particular case, there is an uncoupling between the seasonal evolution of SO(2) and sulphates in the two study periods, which remarks the existence of a sulphate regional background that does not depend on SO(2) local emissions. The decrease of V, Ni and Tl levels reflects the reduction of the industrial activity during the crisis period, affecting mainly the ceramic sector characterised by a great decrease of Tl levels.     

Biomonitoring of polychlorinated biphenyls (PCBs) in heavily polluted aquatic environment in different fish species

The distribution and concentrations of polychlorinated biphenyls (PCBs) were determined in fish species (European perch Perca fluviatilis, northern pike Esox lucius, pike perch Sander lucioperca, wels catfish Silirus glanus, common carp Cyprinus carpio, European eel Anguilla anguilla, freshwater bream Abramis brama, goldfish Carassius auratus, and roach Rutilus rutilus) in a heavily polluted water reservoir Zemplínska ?írava (Slovakia). The study performed at two different time points 5?years apart (2004 and 2009) revealed serious PCB contamination of fish muscle tissue and significant interspecies as well as tissue-specific differences in PCB uptake by fish. Total PCBs broadly correlated with the trophic position of individual fish species within a food chain (P??0.05). The study has shown that the kind of fish, its feeding habit, and specific conditions of the habitat are mutually interrelated factors that are responsible for significant variations in fish body burdens. A tendency to PCB biomagnification was also proved in some fish species of this water reservoir.     

Groundwater contamination evolution in the Guadiamar and Agrio aquifers after the Aznalcóllar spill: assessment and environmental implications

In 1998, the Agrio and Guadiamar rivers underwent an enormous environmental disaster caused by the rupture of the Aznalcóllar tailings dam and the release of 6 hm³ of pyrite sludge and acidic water. Both rivers run over recent alluvial materials which form a small-sized aquifer which is however important because underground water feeds the flow of the rivers. This work analyzes the state of groundwater 10 years after the spill. Before the dam failure, this aquifer was already contaminated in the zone nearest to the mine, to which the impact of the spill was added. Contamination levels in the alluvial aquifer of the Agrio River have decreased remarkably. However, they are still important, with acidic pH values and high concentrations of toxic elements (maximum values of 16 mg/L of Zn and 15 mg/L of Al). There are also important levels of contamination in the Guadiamar alluvial area closest to the mine, as well as in specific zones located further south. The concentration of toxic elements is mainly controlled by pH. The evolution of contaminant levels show a sharp decrease after the first years following the spill, followed by a subsequent stabilization. It is necessary to take measures for the recovery of the aquifer because, otherwise, groundwater will continue contributing contaminants into the Agrio and Guadiamar rivers.     

Tidally driven N, P, Fe and Mn exchanges in salt marsh sediments of Tagus estuary (SW Europe)

Short-sediment cores and flooding water were collected at 0, 5, 15, 25 and 50?min of tidal inundation in the two sites colonised by pure stands of Spartina maritima (low marsh) and Sarcocornia fruticosa (high marsh) from the Rosário salt marsh (Tagus estuary, SW Europe). Concentrations of NH (4) (+) , NO (3) (-) +?NO (2) (-) and HPO (4) (2-) , Fe and Mn were measured in tidal flooding water and pore water. Flooding water is enriched in nutrients, particularly ammonium due to local discharge of untreated urban effluents. Nevertheless, NH (4) (+) and NO (3) (-) +?NO (2) (-) concentrations in flooding waters at t?=?5?min (NH (4) (+) =?246?±?7?μM, NO (3) (-) +?NO (2) (-) =?138?±?1?μM for S. fruticosa and NH (4) (+) =?256?±?8?μM, NO (3) (-) +?NO (2) (-) =?138?±?1?μM for S. maritima) rose sharply at both vegetated sites. An increase was also registered for HPO (4) (2-) and total dissolved Fe although the subsequent decrease was smoother. Advective transport induced by the two daily pulses of inundation is several orders of magnitude higher than the diffusive fluxes during submerged periods. In addition, solutes are exported from the sediment with the inundation and imported in submerged periods. The exported amount of inorganic nitrogen during tidal inundation (export of 3,200?μmol?N?m(-2)?day(-1)to the water column), is not counterbalanced by the sink of -290?μmol?N?m(-2)?day(-1) occurred during the submerged period.