A Survey of Trace Metals in Vegetation, Soil and Lower Animal Along Some Selected Major Roads in Metropolitan City of Lagos

The concentration of trace metals (Cd, Cu, Pb and Zn) in a total of 144 samples of grass, soil and lower animal (earthworm, Lybrodrilus violaceous) were collected and analysed for their metallic content. Levels of cadmium ranged from 0.01–0.07 g g^–1; 0.01–0.12 g g^–1 and from trace–0.05 g g^–1 dry weight for plant, soil and animal samples respectively. Mean concentration of copper ranged 0.10–1.48 g g^–1; 0.10–2.90 g g^–1 and 0.01–0.08 g g^–1 for samples in similar order as above. The levels of Pb varied from 0.01–0.14 g g^–1; 0.02–0.23 g g^–1 and from trace–0.07 g g^–1 while that of Zn ranged from 0.19–1.80 g g^–1; 0.51–3.35 g g^–1and 0.01–0.08 g g^–1 also in the same order of samples as mentioned above. Levels of metals in soil samples were higher than the background levels with the exception of Zn but lower than European Union (EU) limits. The results generally revealed the presence of metals in plant and animal samples and metal dynamics up the food chain is highly possible. Acceptable recoveries of the spiking experiment validate the experimental protocol.     

Pesticide Contamination of Jamaican Environment. II. Insecticide Residues in the Rivers and Shrimps of Rio Cobre Basin, 1982–1996

Only organochlorine (OC) residues were monitored by gas chromatographyin water, sediment and shrimp samples collected everymonth between July 1982 and August 1983 from therivers of Rio Cobre basin. In samples collected everyfour months during 1989–1990, and seven times duringJuly 1995–March 1996, OC and OP (organophosphates)residues were monitored. Carbamate and pyrethroidresidues were not monitored. The detection ofresidues in 1982–1983 was 54 to 100% in water andsediment, and 83 to 100% in shrimp samples fromvarious sampling stations in the four rivers. In otheryears, it ranged from about 40 to 100% in the threetypes of samples.In 1982–1983, DDE and dieldrin residues were found tobe much higher than those of lindane and - and-endosulfan in Black River, Rio Pedro, ThomasRiver and Rio Cobre in the watershed. The ranges ofmeans of each residue in water (g L^-1), sediment(ng g^-1) and shrimp (ng g^-1) samples, respectively, were:DDE, 0.059–102.0, 3.44–13.97, 0.344–14.57;dieldrin, 0.026–173.6, 1.21–2.75, 0.427–5.59;-endosulfan, bdl, 1.75–4.00, bdl;-endosulfan, bdl (below detectable limits), 2.51–9.48, bdl;and lindane, (bdl), 0.110–0.319, 2.90.In 1989–1990 and 1995–1996, residues of six OCs and two OPs were detected quite regularly. DDE, dieldrinand Chlorpyrifos residues were much higher than thoseof the other insecticides. The range of their meansin water (g L^-1), sediment and shrimp (ng g^-1),respectively, were: DDE, 1.66–19.76, 0.941–5.84,1.11–8.32; dieldrin, 0.077–7.22, 0.425–3.31,0.385–1.59; -endosulfan, 0.034–1.25, 0.021–1.22, 0.032–3.62; -endosulfan, 0.665–1.23,0.008–3.60, 0.005–3.97; endosulfan sulphate, 0.959–1.34, 0.035–3.08, 0.012–1.80; lindane, bdl,0.005–0.82, 1.19–1.56; chlorpyrifos, 0.702–4.06,0.005–1.51, 0.156–7.04; and diazinon, bdl, 0–0.150, 0.001–0.006. At the mouth of the river, whereit discharges into the sea, the levels of almost allthe residues were higher than upstream.     

Partition Constants and Adsorption/Desorption Hysteresis for Volatile Organic Compounds on Soil from a Louisiana Superfund Site

The adsorption of four volatile organic compounds (1,4-dichloro-benzene, 1,2-dichloroethane, 1,2,2-trichloroethane and 1,1,2,2,-tetrachloroethane) on three soil types from a Superfund site (Petroprocessors Inc) in Baton Rouge, LA was studied with the purpose of obtaining an overall correlation for inclusion in a groundwater transport model being developed for site remediation. The soil-water partition constant, K_d was determined using a standard ASTM procedure (E–1195–87). Using the data for different soil types (fraction organic carbon between 0.11% and 1.13%) and different mineral surface areas (7 to 45 m²/g), the organic carbon contribution (K_oc) and the mineral matter contribution (K_min) to the partition constant were determined. The soils obtained were either from the Pleistocene period or recent shallow deposits at the site. Both log K_oc and log K_min were linearly correlated to log K_ow, the octanol-water partition constant. This data provided the basis for obtaining a general correlation for K_d on different soil types at the site. The predicted values were in agreement with that for a composite soil from the same site. The desorption of compounds from the high clay soil after the 24 hour adsorption period was observed to show a biphasic behavior, namely, an easily desorbed fraction and a desorption resistant fraction. The easily desorbed fraction was found to be satisfactorily predicted using the conventional K_d as obtained from the adsorption experiment. The slowly desorbing fraction had a time constant of several weeks. The concentration in the desorption resistant compartment was found to be dependant on the initial amount of contaminant available for adsorption. The aqueous phase concentration in equilibrium with the desorption resistant fraction was found to be 8 g/L for dichlorobenzene and 12 g/L for dichloroethane.     

Carbon sequestration in the soils of aquaculture ponds,crop land,and forest land in southern Ohio,USA

Soil samples were collected from four aquaculture ponds (yellow perch culture), a control pond (without aquaculture activities, fallow pond), crop land (under corn), and forest land to estimate the carbon (C) sequestration potential in the Piketon county, Ohio, USA. The averaged total of C was 6.5?±?2, 8.8?±?2, 8.53?±?0.2 and 10.49?±?1.1 Mg/ha (Mg=10⁶g) in <?0.25 mm fraction; 15.2?±?2, 16.0?±?3, 11.49?±?0.8 and 17.23?±?3.4 Mg/ha in micro aggregates (0.25–2.5 mm); and 22.1?±?3, 26.4?±?3, 12.16?±?1.6 and 18.51?±?4.3 Mg/ha in macro aggregates (?>?2.5mm), for aquaculture ponds, control ponds, cropland and forest land, respectively. The soil/sediment C pool followed the order of forest?>?crop land soils?>?aquaculture pond soils.     

Using Mussel Isotope Ratios to Assess Anthropogenic Nitrogen Inputs to Freshwater Ecosystems

Stable nitrogen isotope ratios (¹⁵N) of freshwater mussels from a series of lakes and ponds wererelated to watershed land use characteristics to assess their utility in determining the source ofnitrogen inputs to inland water bodies. Nitrogen isotope ratiosmeasured in freshwater musselsfrom 19 lakes and ponds in Rhode Island, U.S.A., ranged from4.9–12.6 and were found tosignificantly correlate with the fraction of residential development in 100 and 200 m bufferzones around the ponds. Mussel ¹⁵N values in 12 of the 19 ponds also showed significantcorrelation with average dissolved nitrate concentrations, which ranged from 23–327 g L^-1.These observations, in light of previous studies which link elevated¹⁵N values of nitrogenderived from septic wastewater with those seen in biota, suggest that mussel isotope ratios mayreflect nitrogen source in freshwater ecosystems. We followed aniterative approach usingmultiple regression analysis to assess the relationship between mussel¹⁵N and the land usecategories fraction residential development, fraction feedlotagriculture, fraction row-cropagriculture, and fraction natural vegetation in 100 and 200 m bufferzones and pond watersheds.From this we developed a simple regression model to predict mussel¹⁵N from the fraction ofresidential development in the 200 m buffer zone around the pond.Subsequent testing with datafrom 16 additional sites in the same ecoregion led us to refine themodel by incorporating thefraction of natural vegetation. The overall average absolute differencebetween measured andpredicted ¹⁵N values using the two-parameter model was 1.6. Potential sources of error inthe model include differences in the scale and categorization ofland-use data used to generate andtest the model, differences in physical characteristics, such asretention time and range ofresidential development, and exclusion of sources of enrichednitrogen such as runoff from feedlot operations or increased nitrogen loading from inefficient or failed septic systems.     

A Gradient Study of 34 Elements in the Vicinity of a Copper-Nickel Smelter in the Kola Peninsula

Concentrations of 34 elements determined by ICP mass spectrometry were studied in surface soil and vegetation along a north–south gradient through the Pechenganickel smelter complex in Kola peninsula, northern Russia. Strong influence from the smelter was evident for Fe, Co, Ni, and Cu, mainly associated with dry deposition of large particles. Also for As, Se, Mo, Sb, Te, Bi, and Pb the smelter or associated sources appeared to be distinct contributors of contamination consisting presumably of smaller particles. Significant but less distinct effects leading to enhanced concentration levels were observed for P, S, V, Cr, Zn, and Tl. In the case of Mn, Rb, Sr, Cs, and Ba the concentrations in vegetation were generally lower near the source, which may be due to cation exchange with protons or heavy metal cations in the soil and subsequent leaching from the root zone. For Li, Be, B, Na, Mg, Al, Ca, Y, Cd, La, Th, and U no particular influence from the smelter complex was observed. Some characteristic differences observed in element concentrations in different plant species and between different years of Pinus sylvestris needles are discussed. The high concentrations observed for many trace elements in the humus horizon indicates that it acts as an active biogeochemical barrier against downward transport of these elements.     

SEASONAL INFLUENCES OF THE ORGANIC POLLUTION MONITORING OF THE NEW CALABAR RIVER, NIGERIA

Monitoring of the New Calabar River water was conductedmonthly for a period of one year to ascertain seasonalinfluences and industrial effluent discharges on the organicpollution status of the river. Dissolved oxygen (DO) levelsranged between 3.4 and 9.1 mg/l and 4.4–9.0 mg/l for therainy and dry seasons respectively. Total dissolved solids(TDS) levels ranged between 6.5 and 4013.9 mg/l for the rainyseason and 4.32–619.5 mg/l for the dry season. The ranges forthe organic pollutant parameters were: biochemical oxygendemand, 0.25–4.20 mg/l and 0.15–4.95 mg/l; COD, 10–1000mg/l and 15–100 mg/l; oil and grease, 0.00001–5000 g/l and0.00001–800 g/l; anionic surfactants, 2.0–30 gMBAS/l and 0.1–2.0 g MBAS/l for the rainy and dryseasons respectively. The ranges for the same parameters forthe industrial effluent were: DO, 2.1–3.9 mg/l and 6.5–10.8mg/l; BCD, 0.35–1.4 mg/l and 2.3–2.7 mg/l; COD, 508 mg/l and20–576 mg/l; oil and grase, 0.07–50 g/l and0.048–25.0 g/l; and anionic surfactants, 4.0–7.3g MBAS/l and 0,2–17.0 g MBAS/l for the rainyand dry seasons respectively. These results indicate thatseasonal changes as well as industrial effluent dischargesinfluenced the organic load of the river.     

Nitrogen isotope ratios in pine bark as an indicator of N emissions from anthropogenic sources

The article describes the use of Scots pine bark to identifynitrogen sources in eastern Germany, as well as background areas in Russia and Bulgaria, by using natural isotope ratios of total nitrogen (N_t) and individual N compoundssuch as ammonium (NH₄ ⁺), nitrate (NO₃ ^-)and amid nitrogen (amide-N). The samples collected were analysed using an elemental analyser in connection with a gas isotope mass spectrometer (EA-IRMS). Natural ¹⁵N abundances in pine bark from impact areas suggest that the ammonium accumulated on the surface of the bark is releasedfrom livestock management. Bark of Scots pines growing near agricultural land had highly depleted ¹⁵N_t values (between –8 and –12), while bark from background areas (unpolluted areas) displayed slightly negative ¹⁵N_t values (mean ¹⁵N_t = –3.8). It is assumed that part of the N adsorbed on the bark surface is mainly derived from ammonia(mean ¹⁵N_t = –40.3) escaping from livestock housing and during the application of manure. This assumption is confirmed by experiments under controlled conditions in which manure samples were spread on soil. In addition, temporal and spatial variations of ¹⁵N_t abundances in pine bark from various locations in eastern Germany as wellas pine stands in Nature Park Dübener Heath are discussed.     

Impacts of Debris-Flow Deposits on Hydrogeochemical Processes and the Development of Dryland Salinity in the Cross-River Catchment, SE, Nigeria

This research focuses on the effect of debris-flow on thevarious hydrogeochemical processes occurring at Cross-River as aresult of disposal of industrial and household wastes as well as sewage into the river. It also focuses on development anddetermination of the saline nature of the rivers dry land.The study is carried out by a survey at different depths of theriver for water and soil samples analysis.The results show that concentrations of cations and anionsreasonably high and uniform except for nitrates which is quitehigh due to agricultural activities occurring in the study areas.Also Mg and SO₄ ions are high due to reactions within thecolluvium include ion exchange of calcium for sodium in basalclays; dissolution of sodium chloride from dust – derived saltparticles in the clay-rich colluvium reactions.The Electrical conductive shows that Cross-River containsdissolved solids. Soil analysis indicates the presence of K, Ca,Mg, and Cl. pH values were also deducted from soil samples (6.30–6.45).     

Formation and Emission of N2O and CH4 from Compost Heaps of Organic Household Waster

Composting can be a source of N₂O andCH₄ production. In this investigation, differentcompost heaps of organic household waste weremonitored with the focus on potential formation ofCH₄ and N₂O in the heaps and emission ofthese gases from the heaps. The studied compost heapshad different compost ages, turning intervals andcompost sizes. The analysed compost gases containedbetween 1–3421 L of N₂O-N L^-1 and 0–470 mL of CH₄ L^-1. The emission rates ofN₂O and CH₄ from the compost heaps werebetween 1–1464 mg N₂O m^-2 day^-1 and0–119 000 mg CH₄ m^-2 day^-1. These verylarge differences in compost gas composition andemission indicate the importance of compostmanagement. The results also give an understanding ofwhere in the composting process an increasing emissionof N₂O and CH₄ can occur.