Louise Sörme

SOURCES OF HEAVY METALS IN URBAN WASTEWATER IN STOCKHOLM

The sources of heavy metals to a wastewater treatment plant was investigated. Sources can be actual goods, e.g. runoff from roofs, wear of tires, food, or activities, e.g. large enterprises, car washes. The sources were identified by knowing the metals content in various goods and the emissions from goods to sewage or stormwater. The sources of sewage water and stormwater were categorized to enable comparison with other research and measurements. The categories were households, drainage water, businesses, pipe sediment (all transported in sewage water), atmospheric deposition, traffic, building materials and pipe sediment (transported in stormwater). Results show that it was possible to track the sources of heavy metals for some metals such as Cu and Zn (110 and 100% found, respectively) as well as Ni and Hg (70% found). Other metals sources are still poorly understood or underestimated (Cd 60%, Pb 50%, Cr 20% known). The largest sources of Cu were tap water and roofs. For Zn the largest sources were galvanized material and car washes. In the case of Ni, the largest sources were chemicals used in the WTP and drinking water itself. And finally, for Hg the most dominant emission source was the amalgam in teeth. For Pb, Cr and Cd, where sources were more poorly understood, the largest contributors for all were car washes. Estimated results of sources from this study were compared with previously done measurements. The comparison shows that measured contribution from households is higher than that estimated (except Hg), leading to the conclusion that the sources of sewage water from households are still poorly understood or that known sources are underestimated. In the case of stormwater, the estimated contributions are rather well in agreement with measured contributions, although uncertainties are large for both estimations and measurements. Existing pipe sediments in the plumbing system, which release Hg and Pb, could be one explanation for the missing amount of these metals. Large enterprises were found to make a very small contribution, 4% or less for all metals studied. Smaller enterprises (with the exception of car washes) have been shown to make a small contribution in another city; the contribution in this case study is still unknown.

Data Vagueness and Uncertainties in Urban Heavy-Metal Data Collection

The use of societal data inenvironmental research has indicated a need forconsidering uncertainties of data. Severalfundamental conditions for statistical treatmentare occasionally not met. The choice is either touse or to ignore the uncertain data. If used, itmay impair the quality of the result. If ignored,a possible environmental risk may remainunattended. This article discusses some of theproblems encountered with data in urbanheavy-metal metabolism, and suggests a method based onuncertainty intervals to consider theuncertainties.

GOODS IN THE ANTHROPOSPHERE AS A METAL EMISSION SOURCE A Case Study of Stockholm, Sweden

The aim of this study was to quantify the diffuse emissionsduring use of metal containing goods in the capital of Sweden,Stockholm. The following metals were studied: Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), Mercury (Hg), Nickel (Ni) and Zinc (Zn).A major part of the metals are found in a protected environmentwhere degrading processes like corrosion are most limited. However, during the lifetime of some goods the metal release to the environment is significant. The quantitatively most dominant emissions were found for Cu and Zn. The tap water system and roofs/fronts (Cu) represent goods with large exposedareas but with relatively small release rates per unit. In contrast, brake linings, aerial lines and electrical grounding (Cu) and tyres, brake linings and chemicals (Zn) are allgoods with high release rates but mostly limited exposed stocks.High yearly emissions are also found for Pb, ammunition andsinkers dominate the calculated emissions totally. For Cr and Ni, stainless steel represent the major part of the stocks, butcorrosion was estimated to give only a minor contribution to the emissions. Potential emission sources, i.e. stabilisers,pigments and plated goods dominate the exposed Cd stock. Theseemissions were not quantified due to lack of data. Hg is currently phased out, but one major source of emission, i.e. the use of amalgam, will be continuously significant for several decades. The importance of the traffic sector is obvious. The emissionsfrom brake linings (Cu, Zn and Pb), tyres (Zn, Pb, Cr and Ni)and asphalt wear (Cu, Zn, Cr, Ni and Pb) are all of large importance for the total emission from respectively metal.

Century Perspective of Heavy Metal Use in Urban Areas. : A Case Study in Stockholm

The inflow and stock (amount in use) of heavy metals (cadmium(Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn)) in goods in 1995 have been quantifiedin the anthroposphere of Stockholm, Sweden. Statistics on national, regional and local level were used. Contacts were established with representatives from production and constructionin the industrial sector and with authorities. The results show that the stock of Cd is 0,2 kg per capita. For the other heavymetals the corresponding result per capita is: Cr 8, Cu 170, Hg 0,01, Ni 4, Pb 73 and Zn 40 kg. The inflow varies between2–8%of the stock indicating the importance of the stock. The lowestlevels are for Cu and Pb. Heavy metal levels in solid waste are high, between 15–45% of the amount in the inflow (Hg excluded), the lowest values were for Cu and Pb. Thus, recyclingis incomplete. Long life expectancy goods form the majority of the stock but there is a tendency that short life expectancy goods increase their importance in the inflow. Concealedgoods are also more frequent in inflow than in the stock.

Phasing out cadmium, lead and mercury : Effects on urban stocks and flows

Large stocks of metals have accumulated in the urban technosphere (i.e., the physical environment altered by human activity). To minimize health and environmental risks, attempts were begun in the 1980s to phase out the use of cadmium (Cd), lead (Pb), and mercury (Hg). To study the effect of this attempt, we conducted substance flow analyses (SFAs) in Stockholm, Sweden, in 1995 and in 20022003, which allow a comparison of the results over time. The SFAs showed a reduction in the stocks of Cd and Hg by approximately 25% to 30% between 1995 and 20022003. For Pb, the stock development was more uncertain. Cd and Hg inflow was substantially reduced during this period, but Pb inflow increased. Amounts of Cd and Pb in waste were still large, whereas Hg flows in waste were decreasing. Furthermore, although emissions of Pb decreased, Cd and Hg emissions were in the same range as in 1995. The application of SFAs has provided unique data on the accumulation of metals in the Stockholm technosphere, thus serving as a valuable indicator of how the phasing out progresses. The changes can be related to regulations, initiatives by industries and organizations, and the proactive attitude of the local environmental authorities and of the water company.

Sources of antimony in an urban area

Environmental context. The global production and use of antimony (Sb) increase together with stocks and emissions, but there are gaps in our knowledge concerning environmental effects. Here, a reconstruction of major Sb flows in an urban area was conducted. The major emission source of Sb identified was wear of brake linings, although other sources may also be of importance, e.g. diffuse emission of flame-retarded goods. Abstract. The present study sets out to analyse the urban metal sources of Sb, by estimating the stock of Sb in use, and to present related flows and emissions in Stockholm, Sweden, in 2005. Antimony was studied with the main methodology of substance flow analysis with existing data, while chemical analysis was used as a complement. No large point sources were found reported to the authorities; hence, the dominating source for Sb is diffuse and originates from goods. The total Sb stock in Stockholm in 2005 was ~430 000 kg (range 110 000–1 700 000 kg) and the total Sb inflow was estimated at 45 000 kg year–1 (range 30 000–67 000 kg). The stock was dominated by flame-retarded goods, cable shielding, glass and accumulators. The Sb emission was estimated at ~720 kg year–1 (range 430–1200 kg year–1). Despite large uncertainties and missing data, the results supported the notion of the importance of brake linings as a source of Sb emissions (710 kg year–1), whereas other goods such as textiles (4.5 kg year–1), tyres (1.4 kg year–1), sinkers, ammunition and polyethylene terephthalate (PET) bottles and packaging were minor sources. However, flame-retarded goods are still poorly quantified and are seen as a potential emission source.

Upstream silver source mapping - a case study in Stockholm, Sweden

Silver (Ag) can be a problem for wastewater treatment plants (WWTP) and their capability to use sewage sludge as a soil fertilizer. Due to a high accumulation rate in soils, the levels of Ag in the incoming water at the WWTP must be reduced. This study aims to identify major diffuse emission sources in the technosphere through a comprehensive substance flow analysis of Ag in Stockholm, Sweden. Large inflows and stocks of Ag were present in electrical and electronic goods and appliances as well as in jewellery and silverware. The total inflow was 3.2 tonnes (4.2 g/person), the total stock was 100 tonnes (140 g/person) and the total outflow was 330 kg (430 mg/person). Major identified Ag sources with emissions ending up in the WWTP (total 26 kg, 34 mg/person) were food, amalgam and beauty products (via urine and faeces, 12 mg/person or 11% of incoming amount), and textiles (via washing, 17 mg/person or 16% of incoming amount). This study explains approximately 35% of the total 80 kg Ag in the incoming water at Henriksdal WWTP in Stockholm. Plastic, photography and beauty products were identified as possible sources of Ag that need to be examined further.

Persistent Hazardous Waste and the Quest Toward a Circular Economy: The Example of Arsenic in Chromated Copper Arsenate–Treated Wood

The importance of a circular economy is today widely accepted and advocated, but among the challenges in achieving this, we find difficulties in the implementation of legislation and policies desig ...