Long-term Heavy Metal Loading to Near-Shore Lake Sediments

Abstract

Long-term sediment pollution by lead (Pb), copper (Cu) and zinc (Zn) is investigated in Karlskärsviken, a typical bay of Lake Mälaren, about 10 km northwest of Stockholm. We find that metal accumulation rates in the sediments of Karlskärsviken increase considerably more in the outer than in the inner bay section, all the time since medieval times and even more so after than before industrialisation. Resulting metal accumulation rates are dominated by increasing sediment accumulation rate and its spatial-temporal patterns. This indicates significant waterborne metal pollution contributions to the bay sediments, which continue until present times and are still increasing for Zn and Cu. The outer Karlskärsviken bay section is then mainly affected by regional waterborne discharges, while the inner bay section is mainly affected by local discharges, in addition to the atmospheric deposition that affects the whole bay and Lake Mälaren similarly. The present results indicate possible important shortcomings in environmental regulation, management and monitoring systems that consider only sediment concentration levels and neglect pollutant accumulation rates and diffuse metal load contributions from slow subsurface transport into surface water environments.

Distinguishing active and legacy source contributions to stream water quality: Comparative quantification for chloride and metals

“…A study of Cl − sources in a north‐central sub‐catchment (number 727, map for Cl − , Figure 2) reports that use of deicing salt accounts for 61% of the total Cl − load to that stream, followed by fertilizers and manure (14%), infiltration and recharge from surface deposition (13%), dustbinding in gravel roads (7%), municipal and private sewage and discharges from wastewater treatment plants (4%), and leakage from landfills and other minor sources (1%) (Thunqvist, 2004). Furthermore, metals may originate from weathering of bedrock as well as airborne deposition at the surface and waterborne spreading from various anthropogenic sources in this region (Olli & Destouni, 2008). For example, Stockholm and the other main cities in this catchment have existed since hundreds of years, with much soil becoming polluted by industry, waste deposits, sewage, traffic, constructions, accidents, and so forth.…”

Historic sediment accumulation rates in Karlskärsviken, a bay of Lake Mälaren, Sweden

“…Spheroidal particles and particle fragments greater tban half a sphere were counted at x 400 enlargement using a light-microscope. The results are compared to those hy Wik (1992), Rose (1990) and Rose et al (1999) and to lead graphs analysed on the same cores (Olli & Destouni 2008) and to Brannvall et al (2001).…”

General Quantification of Catchment-Scale Nutrient and Pollutant Transport through the Subsurface to Surface and Coastal Waters

“…Much of the nutrient and pollutant loading that threatens the quality and ecosystems of inland and coastal waters is transported through the subsurface (soil, groundwater, sediment) part of the terrestrial water cycle. The nutrient and pollutant loads originate from a variety of sources at and below the land surface such as heavy metal loading from mining wastes and abandoned mine voids − , organic pollutant loading from contaminated land areas , , and nutrient loading from agricultural land, private sewage systems, and pools that remain in the subsurface from earlier anthropogenic inputs − . Potential chemical accidents on land and failure of subsurface nuclear waste repositories , for instance, also involve subsurface transport of chemicals and radionuclides to surface and coastal waters.…”