John G. Farmer

Lead in glasgow street dirt and soul

Abstract The levels of lead in city street dirt and in soil from various locations in Glasgow were investigated during spring 1976. Lead concentrations in street dirt ranged from 150–2300 ppm, mean 960 ppm, and were significantly elevated with respect to the observed “natural” level of 78 ppm. Lead derived from anti-knock compounds in petrol and introduced to the environment via automobile exhausts was clearly implicated as the main source of lead pollution in a series of soil lead measurements at the centre and periphery of eight Glasgow parks. Various chemical leaching techniques were employed and compared. Less than 5% of street dirt and soil lead was found to be associated with the organic phase.

Chemical partitioning of trace metal contaminants in urban street dirt

Abstract From a survey of trace metal contamination in soil and street dirt in Glasgow, 60 street dirt samples were selected for detailed investigation of chemical partitioning via a six-step sequential leaching procedure. Implications for the environmental mobility and bioavailability of lead, zinc, copper and cadmium are presented along with a comparison of soil and street dirt data. Results obtained for the solubilization of lead from street dirt by dilute hydrochloric acid are considered with respect to the health implications of street dirt ingestion by young children and also to the chemical associations revealed in the six-fraction study.

Massive diagenetic enhancement of manganese in Loch Lomond sediments

Abstract Extremely high Mn levels of up to 9.1% have been found in sections of surface or near‐surface sediment in Loch Lomond. The enriched Mn levels, amongst the highest recorded for freshwater lake sediments, are attributable to post‐depositional diagenetic processes which have also influenced sedimentary Fe and As profiles. Although discrete ferromanganese nodules were not found, thin crusts composed of distinct high ‐ Mn and ‐ Fe layers covered parts of the loch bottom.

Records and sources of metal pollutants in a dated Loch Lomond sediment core

Abstract Lead, zinc, copper, chromium, arsenic and cadmium were measured in a sediment core from southern Loch Lomond for which 210 Pb dating indicated a sedimentation rate of 22±2 mg/cm 2 /yr corresponding to a mean accumulation rate of 0.36 mm/yr. While copper and chromium were enriched to only a minor extent, the lead, zinc, arsenic and cadmium concentrations were markedly enhanced in upper sections. Increasing anthropogenic input associated with industrial activity centred on Glasgow seems responsible for the vertical distribution of lead, zinc and cadmium but a high 0–1 cm level of arsenic (474 μg/g), strongly correlated with enhanced iron content in the surface oxidising layer of sediment, appears attributable to post-depositional diagenetic mobilisation and upward migration in the reducing zone of the sediment column. Leaching, using CH 3 CO 2 H/NH 2 OH·HCl, released over 90% and 80% of the common metal pollutants, lead and zinc, from surface sediment. Onset of an approximately tenfold increase in lead and zinc concentrations above “background” levels of 13±2 μ g/g and 47±13 μ g/g to upper section levels of 140–170 μg/g and 450–460 μg/g respectively was placed at late-18th century, in accord with the records of the commencement of significant industrial activity in the Glasgow area. Current anthropogenic fluxes (μg/cm 2 /yr) of lead (2.51±0.34) and zinc (8.84±1.20) to the sediment are in agreement with recent atmospheric deposition data for the adjoining Clyde Sea Area. The general concordance between anthropogenic metal fluxes to Loch Lomond sediment and atmospheric deposition fluxes endorses the potential usefulness of Loch Lomond sediment data to the resolution of pollution sources in the adjoining sea lochs and firth of the Clyde Sea Area, illustrated here through consideration of the comparative distribution of chromium in relation to its historical use.

Urinary arsenic concentrations and speciation in Cornwall residents

Inorganic arsenic and its methylated metabolites were determined in urine from adults and children in Cornwall and from corresponding control groups in Glasgow. In the mineralised south-west of England, where it has been suggested that the highly enriched soil arsenic concentrations may at least be a cofactor in the increased incidence of skin cancer, urinary arsenic levels were, in general, only slightly elevated. The potential for increased intake of inorganic arsenic in Cornwall was, however, reflected in the more frequent occurrence of trivalent inorganic arsenic and monomethylarsonic acid in urine and, of especial significance, in two comparatively highly elevated sum of arsenic species concentrations of 48.7 and 20.8 μg g−1 creatinine recorded for two pre-school children. These findings are discussed with reference to recommended limits and pathways of exposure to inorganic arsenic.

210Pb dating of a Loch Lomond sediment core by conventional and particle track methods and some geochemical observations

210Pb dating of a short Mackereth core, from a suite characterised previously by palaeomagnetic and radiocarbon dating, has been performed using both conventional radiochemical and particle track methods. The latter involves total α and U assay using plastic detectors and untreated sediment pellets. Sedimentation rates determined by the two techniques are in good agreement (∼22 mg cm−2 y−1), suggesting that the simpler particle track method has much to offer in routine sediment dating. The radiometric time scale is totally consistent with heavy metal profiles and the known industrial history of the surrounding area.

Radiocarbon: Short-term variations

Analyses of 19th century single tree rings indicate that natural /sup 14/ C fluctuations of 20% over the 11-yr sunspot cycle have occurred in correlation with solar activity. Consequently, an additional error of at least plus or minus 80 years is inevitable in the radiocarbon age determination of dating samples of lifetime one year. (auth)

Metal pollution in marine sediment cores from the West Coast of Scotland

Levels of the trace metals lead, zinc, copper and chromium were measured in sediment cores from sea lochs Gareloch and Loch Goil in the Clyde Sea Area and from the comparatively remote Minch off the north-west coast of Scotland. Concentrations (CH3CO2H/NH2OH·HCl extractable fraction) of up to 520 μg/g (Pb), 640 μg/g (Zn), 260 μg/g (Cr) and 730 μg/g (Pb), 630 μg/g (Zn), 760 μg/g (Cr) were found in the top 15 cm of sediment from Loch Goil and Gareloch, respectively, but maximum concentrations in the Minch reached only 10·6 μg/g (Pb) and 8·5 μg/g (Zn). Enrichment factors of 17–30 for 6·3–7·8 for Zn, 7·5–8·9 for Cr and 1·2–3 for Cu, reflecting anthropogenic metal pollution, were found for upper layers of Loch Goil sediment relative to background concentrations as removed by CH3CO2H/NH2OH . HCl leaching. Radionuclide studies suggest that bioturbational effects have obscured the sedimentary chronological record of pollutant metal input in the Clyde sea lochs and the Minch. However, consideration of the metal inventories and concentrations in the Clyde sea loch sediments in the light of various potential contributory sources shows that the major input of pollutant metals has been via the Clyde Estuary and the River Clyde. Inventories of ‘excess’ Pb and Zn in Minch sediment are < 1% of those of the Clyde sea lochs and only 5–7% of the integrated atmospheric deposition alone for the Glasgow area as deduced from a Loch Lomond core.

Trace-element speciation and partitioning in environmental geochemistry and health

Establishment of the chemical form and associations of trace elements is important in the scientific and medical fields related to environmental geochemistry and health. Fundamental understanding of trace-element behaviour, the realistic formulation of historical perspectives of trace-element contamination, an assessment of environmental transformation processes and a thorough appraisal of environment-related ill health and disease all depend on knowledge of the chemical speciation and partitioning of trace elements. These topics and the development of analytical speciation techniques and procedures are discussed with reference to trace-element studies in the Department of Forensic Medicine and Science, University of Glasgow, on lacustrine sediments and water, the atmosphere, soil and street dirt of an urban environment and human biological fluids.

Lead concentration profiles in lead-210 dated Lake Ontario sediment cores

Abstract Lead concentrations were measured in sediment cores from four sites distributed among the three major sedimentary basins — Niagara, Mississauga and Rochester — of Lake Ontario for which sedimentation rates had been previously determined by 210 Pb dating. Around 90% of the total lead present in fine-grained surface sediments was removed by CH 3 CO 2 H/NH 2 OH · HCl leaching, concentrations ranging from 137 μg/g in surface sections to a constant background of 12–13 μg/g at unpolluted depths. Lead-210 dating indicated that increases in lead concentrations commenced ca. 1850–1875 with 5, 10, 35 and 50% of the total “excess” lead inventory in the sediment column being assigned to the pre-1900 period and successive 25-year intervals during the 20th Century, respectively. Anthropogenic inputs of lead from such sources as the combustion of leaded gasoline and coal are responsible for these increases. About 10 μg/g lead remained in the sediment residue after leaching. The total natural lead flux to the sediments ranged from 0.4–1.3 μg/cm 2 /yr while “excess” lead of anthropogenic origin varied from 1.2–6.7 μg/cm 2 /yr and totalled 0.5–1.5 g/m 2 at the four sites. Various potential modes of introduction of anthropogenic lead and of 210 Pb to the lake are considered in conjunction with the ratio of Pb/ 210 Pb fluxes to the sediment.