Landscape Planning for Agricultural Nonpoint Source Pollution Reduction III: Assessing Phosphorus and Sediment Reduction Potential

Riparian buffers have the potential to improve stream water quality in agricultural landscapes. This potential may vary in response to landscape characteristics such as soils, topography, land use, and human activities, including legacies of historical land management. We built a predictive model to estimate the sediment and phosphorus load reduction that should be achievable following the implementation of riparian buffers; then we estimated load reduction potential for a set of 1598 watersheds (average 54 km²) in Wisconsin. Our results indicate that land cover is generally the most important driver of constituent loads in Wisconsin streams, but its influence varies among pollutants and according to the scale at which it is measured. Physiographic (drainage density) variation also influenced sediment and phosphorus loads. The effect of historical land use on present-day channel erosion and variation in soil texture are the most important sources of phosphorus and sediment that riparian buffers cannot attenuate. However, in most watersheds, a large proportion (approximately 70%) of these pollutants can be eliminated from streams with buffers. Cumulative frequency distributions of load reduction potential indicate that targeting pollution reduction in the highest 10% of Wisconsin watersheds would reduce total phosphorus and sediment loads in the entire state by approximately 20%. These results support our approach of geographically targeting nonpoint source pollution reduction at multiple scales, including the watershed scale.     

EOX concentrations in sediment in the part of the Bothnian Bay affected by effluents from the pulp and paper mills at Kemi, Northern Finland

The Bothnian Bay, which is the northernmost part of the Gulf of Bothnia in Northern Finland, is affected by effluents discharged from point sources such as the pulp and paper mills of Stora Enso Oyj Veitsiluoto Mill and Oy Metsä-Botnia Ab Kemi Mill at Kemi, and the Kemi municipal sewage plant, as well as the River Kemijoki. In this paper we discuss, how modernisation of the wastewater treatment plant at the mills, and process investments in the Best Available Techniques (BAT) for effluent treatment, have decreased the effluent discharges of biological oxygen demand (BOD), chemical oxygen demand (COD), total phosphorus (Tot-P), total nitrogen (TOT-N), total suspended solids (TSS) and adsorbable organically bound halogens (AOX) from the mills since 1988. One specific aim of the study was to determine the EOX (Extractable Organically Bound Halogens) concentrations in bottom sediment of the Bothnian Bay in order to assess whether the EOX concentrations reflect the reduction in discharges of chlorinated compounds. According to the monitoring program carried out every third year between 1997–2006, the decreasing trend in EOX concentrations in the top 2 cm of the bottom sediment reflect the decrease in organochlorine discharges (AOX) from the mills. In 1997 the EOX concentrations in bottom sediment varied between 3–70 μg of Cl g^?1 (dry weight), and in 2006 between 3.3–32 μg of Cl g^?1 (dry weight).     

Distribution and contamination assessment of heavy metals in sediment of the Second Songhua River, China

The Second Songhua River was subjected to a large amount of raw or primary effluent from chemical industries in Jilin city in 1960s to 1970s, resulting in serious mercury pollution. However, an understanding of other trace metal pollution has remained unclear. The objective of this study was to investigate trace metal contamination in the sediment of the river. Bottom sediment samples were taken in the river between Jilin city and Haerbin city in 2005. An uncontaminated sediment profile was taken in the Nen River at the same time. Total concentrations of Al, Fe, Mg, Ca, K, Na, Ti, Mn, V, Sc, Co, Cu, Cr, Ni, Pb and Zn in the sediment samples were measured by ICP-MS or ICP-OES, following digestion with various acids. Concentrations of Co, Cu, Cr, Ni, Pb and Zn in the surface sediments were 5.1–14.7, 18.5–78.9, 2.4–75.4, 7.2–29.0, 13.5–124.4, and 21.8–403.1 mg/kg, respectively, generally decreasing along the course of the river from Jilin city to Haerbin city. Background concentrations of trace metals were reconstructed by geochemical normalization to a conservative element scandium. Results showed that concentrations of Co, Cr, and Ni in the sediment were generally only slightly higher than or equal to their background values, while concentrations of Cu, Pb, and Zn in the some sediment samples were significantly higher than their background values. In detail, the sediment at Jilin city was moderately contaminated by Cu, and the sediment of the Second Songhua River was moderately contaminated by Pb and Zn. The top layer (0–10 cm depth) and bottom layers (30–46 cm depth) of one sediment profile at Wukeshu town were generally moderately polluted by Pb and Zn. Synthetically, the surface sediment in the studied river section was classified as natural sediment without ecological risk by the sediment pollution index (SPI) of Cu, Cr, Ni, Pb and Zn. Only the 30–45 cm depth of the sediment profile at Wukeshu town was classified as low polluted sediment by the SPI of these metals, recording a historical contamination of the river in the 1960s to 1970s. This buried contamination of trace metals might pose a potential risk to water column under disturbance of sediment. Foundation item: The National Basic Research Priorities Program of China (2004CB418502)     

Biodegradation of mono-alkyl phthalate esters in natural sediments

Mono-alkyl phthalate esters (MPEs) are primary metabolites of di-alkyl phthalate esters (DPEs), a family of industrial chemicals widely used in the production of soft polyvinyl chloride and a large range of other products. To better understand the long term fate of DPEs in the environment, we measured the biodegradation kinetics of eight MPEs (-ethyl, -n-butyl, -benzyl, -i-hexyl, -2-ethyl-hexyl, -n-octyl, -i-nonyl, and -i-decyl monoesters) in marine and freshwater sediments collected from three locations in the Greater Vancouver area. After a lag period in which no apparent biodegradation occurred, all MPEs tested showed degradation rates in both marine and freshwater sediments at 22 °C with half-lives ranging between 16 and 39 h. Half-lives increased approximately 8-fold in incubations performed at 5 °C. Biodegradation rates did not differ between marine and freshwater sediments. Half-lives did not show a relationship with increasing alkyl chain length. We conclude that MPEs can be quickly degraded in natural sediments and that the similarity in MPE degradation kinetics among sediment types suggests a wide occurrence of nonspecific esterases in microorganisms from various locations, as has been reported previously.     

A summary of total mercury concentrations in flora and fauna near common contaminant sources in the Gulf of Mexico

Total mercury concentrations are summarized for environmental media and biota collected from near-coastal areas, several impacted by contaminant sources common to the Gulf of Mexico. Water, sediment, fish, blue crabs, oysters, clams, mussels, periphyton and seagrasses were collected during 1993–2002 from targeted areas affected by point and non-point source contaminants. Mean concentrations in water and sediment were 0.02 (±1 standard deviation = 0.06) μg l⁻¹ and 96.3 (230.8) ng g⁻¹ dry wt, respectively. Mean total mercury concentrations in fish, blue crabs, brackish clams and mussels were significantly greater than those in sediment, seagrass, colonized periphyton and oysters. Concentrations (ng g⁻¹ dry wt) averaged 23.1 (two seagrass species), 220.1 (oysters), 287.8 (colonized periphyton), 604.0 (four species of freshwater mussels), 772.4 (brackish clam), 857.9 (blue crabs) and 933.1 (nine fish species). Spatial, intraspecific and interspecific variability in results limited most generalizations concerning the relative mercury contributions of different stressor types. However, concentrations were significantly greater for some biota collected from areas receiving wastewater discharges and golf course runoff (fish), agricultural runoff (oysters) and urban stormwater runoff (colonized periphyton and sediment). Marine water quality criteria and proposed sediment quality guidelines were exceeded in 1–12% of total samples. At least one seafood consumption guideline, criteria or screening value were exceeded in edible tissues of blue crabs (6% total samples) and nine fish species (8–33% total samples) but all residues were less than the US Federal Drug Administration action limit of 1.0 ppm and the few reported toxic effect concentrations available for the targeted biota.     

The dualistic approach of FCA: a further insight into Ontario Lake sediments

The investigation of object-by-attribute matrices is very common in statistics and data analysis with the aim of uncovering every possible relationship among objects and/or attributes. Formal Concept Analysis (FCA) is a method, which stems directly from partial order and lattice theory, which provides an efficient tool to symmetrically uncover linkages among objects and attributes whenever a relation stands among the two sets. It provides efficacious graphical representation and computes association rules between attributes, thus helping in the detection of possible synergism or antagonism of attributes. In this paper, FCA potentialities are discussed and described by means of a case study already investigated by other partial order techniques: the case of Lake Ontario sediment samples. Data derive from a ‘test battery’ for a simultaneous analysis of degradation of Lake Ontario samples, which are basically of two typologies: hygienic and toxicity tests. A multi-valued approach is adopted to cope with the ordinal feature of data. Results highlight interesting interaction among hygienic compounds and a synergism between the two toxicity tests.     

Octyl and nonylphenol ethoxylates and carboxylates in wastewater and sediments by liquid chromatography/tandem mass spectrometry

This work presents an LC–MS–MS-based method for the quantitation of nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs) in water, sediment, and suspended particulate matter, and three of their carboxylated derivatives in water. The alkylphenol ethoxylates (APEOs) were analyzed using isotope dilution mass spectrometry with [¹³C₆]-labeled analogues, whereas the carboxylated derivatives were determined by external standard quantitation followed by confirmation using standard additions. The method was used to study APEO’s behavior in a wastewater treatment plant (WWTP), where total dissolved NP0-16EO concentration was reduced by approximately 99% from influent (390 μg l⁻¹) to final effluent (4 μg l⁻¹), and total OP0-5EO concentration decreased by 94% from 3.1 to 0.2 μg l⁻¹. In contrast, the carboxylated derivatives were formed during the process with NP0-1EC concentrations increasing from 1.4 to 24 μg l⁻¹. Short-chain APEOs were present in higher proportions in particulate matter, presumably due to greater affinity for solids compared to the long-chain homologues. NP (0.49 μg l⁻¹) and NP0-1EC (4.8 μg l⁻¹) were the only APEO-related compounds detected in a surface water sample from a WWTP-impacted estuary; implying that 90% of the mass was in the form of carboxylated derivatives. Sediment analysis showed nonylphenol to be the single most abundant compound in sediments from the Baltimore Harbor area, where differences in homologue distribution suggested the presence of treated effluent in some of the sites and non-treated sources in the rest.     

Trace metals assessment in water, sediment, mussel and seagrass species--validation of the use of Posidonia oceanica as a metal biomonitor

The accumulation of trace metals (Cd, Co, Cr, Hg, Ni and Pb) was measured in water, sediment, the mussel Mytilus galloprovincialis and the seagrass Posidonia oceanica. Samples were collected in three locations of the north-western Mediterranean (Canari, Livorno and Porto-Torres) which present different levels and sources of human impact. Analyses in the different compartments (water, sediment, M. galloprovincialis and P. oceanica) have allowed to identify Canari as the most Cd, Co, Cr and Ni contaminated site; Livorno as the most Hg contaminated and Porto-Torres as the most Pb contaminated. Furthermore, for the first time, metal concentrations found in P. oceanica have been compared with those found in the water column, in the sediment and in the recognized metal bio-indicator species M. galloprovincialis and the results obtained have led to the same conclusions. Thus, this study allows to validate the use of P. oceanica as metal biomonitor of coastal waters.     

Monitoring morphological and vegetation changes and flow events in dryland river channels

Monitoring of impacts of floods in river valleys of dryland regions has become important with the onset and threats of desertification and is likely to become even more vital with predictions of increased effects of climate and land use change. It is also needed in order to conform to requirements of the EU Water Framework Directive. Monitoring in such regions sets particular challenges. This paper explains a system of low-cost monitoring of changes in morphology, vegetation and sediment cover in channels and valley floors of ephemerally flowing streams. It has been applied in SE Spain for 10 years and has proved very effective. In particular, the use of simple crest-stage recorders for measuring flow height and the use of real-time differential GPS for rapid and accurate survey and for relocating points have proved very valuable. Part of the monitoring is focused on the interaction of plants and channel processes. Small changes in and around vegetation associated with flow events have been detected by a combination of quadrat surveys and cross-profiling of the channel. A range of flow events has been measured over the period of monitoring, demonstrating their differing effects and the varying sensitivity and responsiveness of different sites. The sporadic occurrence of flood events in such an environment means that a strategy of monitoring several sites and of continuation over many years has great benefits.     

吹扫捕集-GC-MS测定废水中的硝基氯苯

建立了吹扫捕集-GC-MS测定水样中硝基氯苯类化合物的方法.考察了吹扫温度、吹扫时间等对吹扫捕集效率和方法检出限的影响.在室温下,当吹扫时间为30 min时,该方法的最低检出限可达0.002 mg/L,工作曲线的线性范围为2×10 -3 ～2 mg/L,相对标准偏差在2%～6%,加标回收率在97.0%～110.0%.与国家标准方法相比,该法具有操作简便、灵敏度高、线性范围宽且无须使用有毒有机溶剂等优点,可满足工业废水和地表水中硝基氯苯的测定要求.