SEGH Articles

# An historical reconstruction of atmospheric heavy metals deposition from a peat bog record on the North Shore of the St. Lawrence Estuary, Quebec

01 October 2013
Peat bogs were used to reconstruct the history of atmospheric heavy metal deposition along the St. Lawrence Valley. Results from one of the study sites were presented at the 29th SEGH held in July 2013, Toulouse.

Steve Pratte is currently a Ph.D. student at the Department of Earth and Atmospheric Sciences of Université du Québec à Montréal (UQAM, Canada) and the National Polytechnical Institute of Toulouse (INPT, France). The research presented at the 29th SEGH Conference in Toulouse won the Hemphill prize for best poster presentation in July.  The research was carried out during his Master’s degree in Earth and Planetary Sciences at McGill University in Montreal, under the supervision of Dr. Alfonso Mucci and Dr. Michelle Garneau.

Human activities, especially since the Industrial Revolution, have left a legacy of trace metal contamination that is potentially harmful for natural ecosystems and human health (e.g. As, Cd, Pb) and affected their geochemical cycles. Atmospheric metal pollution is recorded in different environmental archives such as lake and marine sediments, snow and ice and peat bogs. Among these archives, peat bogs have proven to be effective in reconstructing the history of atmospheric metal deposition throughout Europe, but few studies have been carried out in North America or in Quebec. Being an important natural wind corridor, oriented from south-west to north-east, the St. Lawrence Valley is affected by long-range transport of contaminants.

The present study focuses on the reconstruction of the history of atmospheric As, Cd, Ni, Pb and Zn deposition in surface cores (<100 cm) from three peat bogs along the St. Lawrence Valley (Fig.1). Core chronologies were established using 210Pb for the upper horizons and 14C dating for the deeper sections. Metal accumulation rates were computed from measured concentrations and core chronologies. Stable lead isotopes (204, 206, 207 and 208) were also analysed to distinguish natural and anthropogenic sources of Pb. Arsenic, cadmium, lead and stable lead isotopes results from one of the study sites (Baie bog) were presented at the 29th SEGH conference.

Study site locations

In short, the Baie bog recorded the main trends in industrial activities since the Industrial Revolution. The site receives more pollution from Canadian than US sources in reason of its greater distance from the main industrial and urban sources. Mitigation policies (phasing-out of leaded gasoline, Clean Air Act) have been effective in reducing metal emissions and deposition in the environment. Nevertheless, other sources than leaded gasolines are still contributing to Pb and other metal emissions.

Link to an article in Atmospheric Environment arising from this study.

http://www.sciencedirect.com/science/article/pii/S1352231013005943

Steve Pratte

Department of Earth and Atmospheric Sciences of Université du Québec à Montréal (UQAM, Canada) and the National Polytechnical Institute of Toulouse (INPT, France).

Keep up to date

Eldoret, Kenya

06 July 2020

## 37th SEGH International Conference: Geochemistry for Sustainable Development

Nanjing City, China

09 November 2020

30 December 2020

## SubmitContent

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

## Science in theNews

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

• Distribution of metal(loid)s in particle size fraction in urban soil and street dust: influence of population density 2020-01-18

### Abstract

Assessment of street dust is an invaluable approach for monitoring atmospheric pollution. Little information is available on the size distribution of contaminants in street dusts and urban soils, and it is not known how the population density would influence them. This research was carried out to assess the size distribution of trace metal(loid)s in street dust and urban soil, and to understand how population density might influence the size-resolved concentration of metal(loid)s. Three urban areas with a high, medium and low population density and a natural area were selected and urban soil and street dust sampled. They were fractionated into 8 size fractions: 2000–850, 850–180, 180–106, 106–50, 50–20, 20–10, 10–2, and < 2 µm. The concentration of Pb, Zn, Cu, Cd, Cr, Ni, As, and Fe was determined, and enrichment factor and grain size fraction loadings were computed. The results indicated that the concentration of Pb, Zn, Cu, Cd, and Cr was highly size dependent, particularly for particles < 100 µm, especially for street dust. Low concentrations of Ni and As in street dust and urban soil were size and population density independent. Higher size dependency of the metals concentration and the higher degree of elemental enrichment in the street dust fractions than the urban soils indicate higher contribution of human-induced pollution to the dust. Findings also confirm the inevitability of size fractionation when soils or dusts are environmentally assessed, particularly in moderately to highly polluted areas. Otherwise, higher concentrations of certain pollutants in fine-sized particles might be overlooked leading to inappropriate decisions for environmental remediation.

• Soil–plant system and potential human health risk of Chinese cabbage and oregano growing in soils from Mn- and Fe-abandoned mines: microcosm assay 2020-01-17

### Abstract

In Portugal, many abandoned mines are often close to agricultural areas and might be used for plant food cultivation. Soils in the vicinity of two Mn- and Fe-abandoned mines (Ferragudo and Rosalgar, SW of Portugal) were collected to cultivate two different food species (Brassica rapa subsp. pekinensis (Lour.) Hanelt and Origanum vulgare L.). Chemical characterization of the soil–plant system and potential risk of adverse effects for human health posed by plants associated with soil contamination, based on the estimation of hazard quotient (HQ), were assessed in a microcosm assay under greenhouse conditions. In both soils, the average total concentrations of Fe and Mn were above the normal values for soils in the region and their concentration in shoots of both species was very high. Brassica rapa subsp. pekinensis grew better in Ferragudo than in Rosalgar soils, and it behaved as an excluder of Cu, Mn, Fe, S and Zn in both soils. The HQ for Cu, Fe, Mn and Zn in the studied species grown on both soils was lower than unit indicating that its consumption is safe. The high Mn tolerance found in both species might be due in part to the high contents of Fe in the soil available fraction that might contribute to an antagonism effect in the uptake and translocation of Mn. The obtained results emphasize the need of further studies with different food crops before cultivation in the studied soils to assess health risks associated with high metal intake.

• Concentration, fractionation, and ecological risk assessment of heavy metals and phosphorus in surface sediments from lakes in N. Greece 2020-01-13

### Abstract

The presence of phosphorus (P) and heavy metals (HMs) in surface sediments originating from lakes Volvi, Kerkini, and Doirani (N. Greece), as well as their fractionation patterns, were investigated. No statistically significant differences in total P content were observed among the studied lakes, but notable differences were observed among sampling periods. HM contents in all lakes presented a consistent trend, i.e., Mn > Cr > Zn > Pb > Ni > Cu > Cd, while the highest concentrations were recorded in Lake Kerkini. Most of the HMs exceeded probable effect level value indicating a probable biological effect, while Ni in many cases even exceeded threshold effects level, suggesting severe toxic effects. P was dominantly bound to metal oxides, while a significant shift toward the labile fractions was observed during the spring period. The sum of potentially bioavailable HM fractions followed a downward trend of Mn > Cr > Pb > Zn > Cu > Ni > Cd for most lakes. The geoaccumulation index Igeo values of Cr, Cu, Mn, Ni, and Zn in all lakes characterized the sediments as “unpolluted,” while many sediments in lakes Volvi and Kerkini were characterized as “moderately to heavily polluted” with regard to Cd. The descending order of potential ecological risk $$E_{\text{r}}^{i}$$ was Cd > Pb > Cu > Ni > Cr > Zn > Mn for all the studied lakes. Ni and Cr presented the highest toxic risk index values in all lake sediments. Finally, the role of mineralogical divergences among lake sediments on the contamination degree was signified.