The water quality of a stream affected by miningactivities was investigated on the basis of a mineralogical studyfor the related solids, and their subsequent changes weremonitored for a year, so as to clarify the impact of the acidmine drainage (AMD) to the stream. The mine-affected stream wasclassified into Ca–Mg and sulfate type, and the concentrations ofits major constituents ranged from tens to hundreds times higherthan those of the background stream. This was most likely due toacid-generating reactions involving the oxidation of sulfides inthe mineralized zone, and subsequent neutralizations involvingcalcite and chlorite as possible sources of Ca and Mg,respectively. This interpretation is consistent with thethermodynamic and mass-balance calculations. The concentrationsof the dissolved constituents changed seasonally, dependinglargely on rainfall in the mine-affected stream. However, thedramatic decrease in the ratio of Mg/Ca, independent of rainfall,indicates that some changes did occur in sources, including theheterogeneous distribution of main source materials, the changein chemical conditions, especially in pH, pe(Eh), and PCO ₂,in the reacting fluid, and the consequential solubility changesin sources. In spite of the limitations of short-term monitoring,it does provide some meaningful information in order to constructa long-term monitoring program.

Six seaweed species of the Rhodophyta family were sampled for atwo-year period from June 1996 to August 1998 along the Atlanticcoast of Ghana (part of the Atlantic Ocean). The species wereanalysed to determine the levels of eleven chemicalelements namely: Al, As, Br, Cd, Fe, La, Mn, Ni, Hg, V and Zn byInstrumental Neutron Activation Analysis (INAA). Al, Br, Ni, andZn were measured in all the seaweed species studied. The elementAl generally showed the highest concentrations in most of thespecies analysed while Hg levels were the lowest. Precision andaccuracy of the method have been evaluated and the detectionlimits also calculated. The results showed high variability inand between species, among sampling sites and times ofcollection. The high values of metal concentrations in themacroalgae suggest that these marine organisms can be used asbiological indicators for studing marine pollution.

Bacterial contamination of drinking water wells is a commonproblem in many rural areas. Some of this contamination may berelated to manure spreading or housing of livestock; another source is on-site septic systems. Current indicator organisms are able to detect the presence of fecal contamination, but where there may be more than one potential source of fecal material, the current indicators are unable to ascertain the origin. This laboratory investigation was undertaken to determine the longevity and reliability of a selected suite of indicator organisms. Total coliform, fecal coliform, fecal streptococci and Clostridium perfringens were monitoredin a simulated contaminated groundwater environment for 6 months. All four indicator organisms were present at the end of6 months. The number of fecal streptococi bacteria decreased most noticeably, allowing assessment of relative age of contamination. C. perfringens was found to be a reliableindicator of contamination from animal manure. Fecal material from 28 different animals and three septic systems were assessed for the presence of the indicator organisms. Totalcoliform, fecal coliform and fecal streptococci were present in the fecal material of all animals tested including reptiles.C. perfringens was detected in feces from all but two of the animals assessed. Using an assemblage of indicator organisms provides more information regarding source and timingof contamination than just testing for total coliform and fecalcoliform bacteria.

The maintenance of safe-drivingconditions in snow and ice-affected areas in thewintertime includes the use of sodium chloride (NaCl)as de-icing salts. In this study, the impact of NaClon soil-colloid mobilisation and exchangeablebase-cation leaching has been evaluated. The chemistryof groundwater samples below an infiltration trenchfor highway runoff and leachate from column studiessuggested that soil-colloid mobilisation had occurred,as the exchangeable sodium (Na) concentration and theelectrical conductivity (EC) in the groundwater/columnleachate reached the threshold values for colloiddispersion. Generally, samples with no dispersionproblems had high Na and calcium (Ca) concentrations,suggesting that the initial effect of the de-icingsalt was to stabilise the colloids. In the columnstudy there was a good agreement between the degree ofcolloid dipersion problems and lead (Pb) concentrationwhen the pH value was above 7.0. Significant negativecorrelations between Na/CEC (cation exchange capacity)and Ca/CEC in roadside soils from three sitesindicated that Na preferentially displaces Ca from theexchange sites. However, the groundwater dataindicated that Na ions also displace potassium (K) andmagnesium (Mg). A positive effect of NaCl seen at onesite was an increase in the K concentration, which ishighly likely an effect of Na ions displacing fixed Kbetween the layers of 2:1 type clay minerals. In soilslacking these types of clay minerals, severe Kshortage may result from a high plant demand combinedwith the low K concentration in the readily availablefractions in the original soil and a highsusceptibility to leaching. The most significantimpact on soil exchange processes was found to occurwithin 6 m from the road.

To compare the soil remediation effectiveness of saltsof weak organic acids with strongchelating agents, three soils of different textures,all polluted by heavy metals, were washed in a column,at optimum pH, with salts of weak organic acids,namely, citrate, tartarate or oxalate + citrate orchelating agents (EDTA or DTPA). For the clay loam,Cr, Mn, Hg and Pb were removed by citrate andtartarate at levels of 43 to 45, 37 to 41, 91 to 92and 75%, respectively. EDTA and DTPA effectivelyleached only Pb after 20 pore volumes. For the loam,citrate leached 98 and 89% of Cd and Pb after 20 porevolumes, respectively, while tartarate leached out 91and 87% of Cd and Pb. EDTA and DTPA removed 93 to97% of these metals after 20 pore volumes. For thesandy clay loam, 84 to 91, 73 to 84, 56 to 70 and 72to 81% of Cd, Cu, Pb and Zn were removedrespectively, by citrate and tartarate. EDTA and DTPAremoved 93 to 97% of these metals after 20 porevolumes. An in situ soil remediation simulation wasalso tested using the sandy clay loam in a tub. After12 hr of retention, the citrate solution washed 81, 82,73 and 90%, of Cd, Cu, Pb and Zn, respectively, aftersix pore volumes. EDTA and DTPA effectively removedall heavy metals, except for Hg, but also extractedlarge quantities of soil nutrients and pollute thesoil by being adsorbed on the soil particles. Thesalts of citrate and tartarate effectively removed theheavy metals from the three polluted soils whileleaching little macro-nutrients and improving soilstructure. Each soil reached C and B levels ofsoil-clean-up criteria after 10 to 20 pore volumes andwithin 10 to 15 hr of flushing.

Polycyclic aromatic hydrocarbon and heavymetal (Pb, Cd, Cu, Zn, Hg, Fe, Co, Cr, Mo) contentswere established in soil and plant samples collectedin different areas of the railway junction IławaGłówna, Poland. Soil and plant samples werecollected in four functional parts of the junction, i.e. the loading ramp, platform area, rolling stockcleaning bay and the railway siding. It was found thatthe PAH contamination of soil and plants was thehighest in the platform area and near the railwaysiding and lowest in the loading ramp and cleaning bayareas. The contamination exceeded control levels up toalmost twenty fold. The heavy metal contaminationpattern was different. The soil and plants were veryhighly contaminated in the cleaning bay and side trackareas while the loading ramp and platform areas wereless contaminated. A particularly high pollution levelwas observed for mercury in the cleaning bay area.Also lead, zinc and copper pollution levels wererelatively high in the cleaning bay and side trackareas. No significant increase in molybdenum contentwas observed in comparison with the control area.

Atmospheric emission of volatilepesticides can be a significant source of airpollution. A field study was conducted to reduce1,3-dichloropropene (1,3-D) emission by applying thechemical via subsurface drip irrigation with a reduceddosage (4.7 g m⁻² or 47 kg ha⁻¹). Comparisons were made between ashallow drip application with the plot covered with apolyethylene film, a deep drip application and aconventional shank injection (at 11.2 g m⁻²) withthe plots left as bare soil surface. For eachtreatment, seven replicated active flux chambers wereused continuously to measure 1,3-D loss until nomeasurable emission was found. Results indicated thattotal 1,3-D emission loss was over 90% for the shankinjection, and 66 and 57% for the shallow and deepdrip plots, respectively. The emission loss wasextremely high for shank injection since about 80%were lost from the bed furrows where the slantedshanks left uncompacted fractures. On mass basis, theshank plot lost 10.4 g m⁻², whereas the shallow-and deep-drip plots lost 3.1 and 2.7 g m⁻²,respectively. Applying 1,3-D using subsurface dripirrigation with reduced dosage has a great potentialfor emission reduction.

Seven sediment cores were collected along a transect about20 km off from the mouth of the Po River, in the northernAdriatic Sea (Italy). Cores were characterised by differentdepositional sequences associated with late Pleistocene-Holocene lowstand (LST), transgressive (TST) and highstand (HST) system tracts. Sediment samples were analysed for mercury, copper, nickel, chromium, manganese and iron, aswell as for total organic matter. Metal distributiongenerally showed vertical and spatial variability ascribed tograin size effects with no significant anthropogenicperturbation. Conversely, mercury showed vertical profilescharacterised by surface enrichment, with concentrations inthe upper layer (50–230 ng g⁻¹) exceeding 3–11 times the background value of 20 ng g⁻¹ determined in bottomcores. Surface maxima were attributed to anthropogenic mercurydelivered mainly by the Po River.

The determination of chlorocarbons in drinking wateris described. The chlorocarbons studied include:tetrachloromethane, 1,1,1-trichloroethane, tribromomethane,bromodichloromethane, dibromochloromethane. Three methods ofsample preparation were compared: liquid-liquid extraction(LLE), purge & trap (P&T) and direct aqueous injection (DAI).The samples of drinking water were taken from Toruń (Poland):local sources, municipal water intake, drilled wells. Theobtained data allowed to create the map of chlorocarbonscontamination for Toruń town. Repeatability, linearity anddetection limits of LLE, P&T, DAI were evaluated forhalocarbons under investigation.

The aim of this work was to evaluate antimony (Sb) as apotentially valuable tracer of the anthropogenic impact on soilsand estuarine sediments. Antimony was determined in fifteenroadsoils from a medium-size city, La Coruña (NW of Spain);and twelve sediments from two estuaries (La Coruña and Ares-Betanzos). Sb determination was accomplished in a rapid andreliable way by directly measuring the solid samples with anautomatic ultrasonic slurry sampling-ETAAS device. Soil contentsranged from 0.29 to 8.81 μg g⁻¹. A relation between Sbconcentration and motor vehicle intensity was observed.Regarding estuarine sediments, Sb amounted from 0.22 to 1.51 μg g⁻¹, for the La Coruña estuary and 0.24 to 0.71 μg g⁻¹, forthe Ares-Betanzos estuary; higher Sb values were found forcoastal locations whereas lower contents corresponded to `inner'samples. In order to confirm these findings, other pollutantswere studied: As, Cd, Co, Cr, Cu, Ni, Pb, Zn, aliphatichydrocarbons (AH) and polycyclic aromatic hydrocarbons (PAH).These values, along with the Sb ones, were subjected tomultivariate studies intended to elucidate whether Sb correlated(and to what extent) to other well-known anthropogenic pollutants. Thus, Sb became associated to Cd, Cu, Pb and Zn in road soils and to As, Cu, Zn, PAH, Pb and unresolved hydrocarbons, in sediments.