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Possible Control of EU Priority Substances in Danish Waters 8 Assessment of nickel
8.1 Definition of the reference state8.1.1 IntroductionNickel (CAS no. 7440-02-0) is an element, and it is therefore not degradable in nature. Besides metallic nickel there are also a number of nickel compounds to consider. Nickel is essential to animals and plants. Generally, the main impact of nickel on humans is considered to be allergic reactions (contact allergy). Nickel compounds are regarded as having a relatively high water solubility and mobility in soil. The mobility depends, however, strongly on the pH and the sorption capacity of the soil in question /1/. 8.1.2 Main uses and pollution sourcesNickel is primarily used in stainless steel, but will also be present as an alloy component in other steels as well as in cupper alloys. Nickel is furthermore widely used for plating, catalysts, NiCd batteries and pigments. Unintentionally, nickel is consumed with fossil fuels, phosphate-based fertilizers, agricultural chalk, and cement etc. The consumption of nickel in Denmark in 1992/93 was estimated at 5400-7800 tonnes/year /2/. Intentional uses were responsible for a consumption of 5200-7300 tonnes/year while unintentional uses accounted for about 240-480 tonnes /2/. The most important pollution sources of nickel to the environment may briefly be listed as follows: Air Water Soil 8.1.3 Releases to and state of the aquatic environmentThe most important sources of nickel released to the water environment comprise:
Direct industrial releases may come from industries using nickel as a catalyst, undertaking nickel plating, or processing stainless steel or copper alloys. Precise knowledge of the importance of the different industrial sources is not available. The total amount of nickel released into the aquatic environment in 1992/93 by such activities was estimated at 0.5-1.0 tonnes/year /2/. Effluents from sewage treatment plants as well as discharge into stormwater result from a number of sources. The most important source is probably the presence of nickel in bitumen used in tarmac on roads. This nickel is released as dust and collected and discharged with stormwater both directly from stormwater outlets and indirectly via sewage treatment plants. Another important source is wear of plated surfaces resulting in nickel metal and nickel ions being lost to soil and street surfaces and from there washed off by rain. The total amount of nickel released to the aquatic environment in 1992/93 by wastewater and stormwater was estimated at 13-14 tonnes/year /2/. This figure also includes a small contribution from atmospheric deposition. Furthermore, atmospheric deposition is an important direct source of nickel to Danish interior waters. The contribution in 1992/93 was estimated at 15 tonnes yearly. It should be noted that an important source of nickel in Danish freshwater streams and lakes in many places may be due to the natural content in groundwater as well as leaching of nickel from agricultural soils as agricultural soils contain nickel originating from feedstuff as well as from the use of phosphate fertilizers and atmospheric deposition having taken place for many years. Table 8-1 Monitoring data for nickel (average values). The values in parenthesis are the 95 % percentiles. Sources: /4/ /5/ /6/ /7/.
* Average value of 50 % percentile values for five Danish freshwater streams. Based on the median values in sewage and in stormwater runoff presented in table 8-1, the total Danish releases of nickel to the aquatic environment can be estimated at about 3900 kg/year and 2900 kg/year respectively. EQS proposal The proposed water quality criteria (EQS) for nickel is AA-EQS = 20 μg/l (all surface waters) while no MAC-EQS has been defined in the proposal (stated to be "not applicable"). The background concentration in freshwater used in the elaboration of the EQS proposal for nickel was 2.1 μg/l ("dissolved"), a value determined for the river Rhine. 8.1.4 Existing legislation/regulation and their impactStatutory Order no. 24 of 14 January 2000 from the Ministry of the Environment on prohibition of the import and sale of certain products containing nickel (as amended by EU directive 2004/96/EEC of 27 September 2004 by Statutory Order no. 789 of 12 August 2005 from the Ministry of the Environment). The Order restricts the use of nickel from products intended to be in long-term direct contact with the skin . Assessment The Order has no significant impact on releases of nickel to the aquatic environment. Statutory Order no. 998 of 12 October 2004 from the Ministry of Food, Agriculture and Fisheries on nickel in feedstuff Fat containing 10 mg Ni/kg or more must not be used for manufacturing of feedstuff or sold and used for feeding of animals. Assessment The Order reduces the amount of nickel released to agricultural soil and thereby eventually also the amount of nickel leached from soil to fresh water bodies. Act no. 414 of 14 June 1995 from the Ministry of the Environment on a charge on lead accumulators (closed nickel-cadmium batteries) and Act no. 404 of 14 June 1995 (as amended by Act 1105 of 29 December 1999) on remuneration in connection with collection of hermetically sealed nickel-cadmium accumulators (closed nickel-cadmium batteries). NiCd-batteries have to be labelled and are subject to a sales tax, which, in turn, is used to finance a payment scheme for batteries collected for recycling. Assessment The Acts make NiCd batteries financially less attractive to the consumer and encourage collection organisations to collect the batteries for recycling purposes. Thereby both Acts contribute to the objective of reducing the amount of batteries ending up in waste incineration plants and the emission of nickel to the air etc. caused by such batteries. The Acts have been passed to control cadmium, but they will have an effect on nickel as well. Other regulation relevant for cadmium includes:
Assessment The Orders may have a direct impact on the emission to the air and the aquatic environment, depending on how the rules are actually established. 8.1.5 Conclusion on the need for further regulationThe data presented in table 8-1 show that the present concentrations in sewage effluent already comply with the proposed AA-EQS even at the 95% percentile level. Also, the levels observed in stormwater are slightly lower than the AA-EQS (no MAC-EQS has presently been defined for nickel). Furthermore, the values in table 8-1 are for the total content of nickel while the EQS values are for dissolved nickel. It is assessed that at least 75% of the total nickel content (probably more) is particle bound and, hence, the concentrations to be compared to the EQS will in reality be significantly lower than those stated in table 8.1. Apart from regulations on waste incineration plants and discharge permits issued to specific industrial companies, the existing regulatory instruments do not seriously restrict releases, nor will they further reduce releases of nickel to the aquatic environment. In conclusion, there is no need for further progressive reduction in Scenario A while in Scenario B there is an obligation to progressively reduce emissions, discharges and losses also after the EQS has been achieved. Possible technical measures are described in the following. Nickel is not a priority hazardous substance. Hence, there is no obligation to cease/phase out emissions, discharges and losses completely. 8.2 Possible reduction/elimination measures8.2.1 Technical measures to reduce/eliminate nickelThe following options for further reduction of releases of nickel to the aquatic environment may be considered:
8.2.2 Possible synergies with other (priority) substancesA significant fraction (more than 40 %) of the nickel released into the aquatic environment appears, as mentioned in section 8.1.3, to be stormwater runoff from separate systems. Therefore, an initiative to reduce this input could be considered though it is considered technically as well as economically unrealistic to introduce measures specifically for nickel. It is assessed that technological measures that aim to detain suspended particles in surface runoff will significantly reduce the loads of nickel and many other PS/PHS on the aquatic environment. Since this type of measure is not substance specific, it is described technically and assessed economically in a separate chapter (Chapter 13). 8.3 Economic AssessmentIn the technical assessment it was concluded that there is no need for further national reduction measures in Scenario A, while in Scenario B there is an obligation to continue the progressive reduction. However, no sources of economic data on the technical measures for substitution could be identified. For instance, the possible additional costs associated with replacing nickel in bitumen used for tarmac are not known. Since the technologies and measures available for substitution are relatively complex or only possible using technology and/or substitutes that are not yet commercially available on the market, it must be assessed that the cost of substituting nickel in the remaining uses would be relatively high. Attention therefore turns from abatement to clean-up measures. More than 40 % of the nickel released into the aquatic environment is estimated to stem from stormwater runoff from separate systems. Therefore, an initiative to reduce this input should be considered for Scenario B, which implies an obligation to progressively reduce the emissions and discharges even after compliance with the EQS has been achieved. The cost-effectiveness of such a measure should, however, be evaluated not only with regard to nickel, but as a common measure. This is done in Chapter 13. 8.4 Conclusion on nickelAccording to the monitoring data available, the concentrations of nickel in various discharges and in surface waters do not pose a problem in relation to compliance with the proposed EQS value. Nickel is one of the two substances (mercury is the other) included in this study for which the total load on surface waters from sewage effluent is larger than that from discharge of stormwater (approx. 60 % in sewage). It is concluded that there is no need for further national reduction measures in Scenario A while in Scenario B there is a need for further national reduction measures to fulfil the obligation to progressively reduce emissions, discharges and losses also after the EQS has been achieved. The possible further reducing measures (Scenario B) include implementing general measures to reduce the content of suspended matter in stormwater prior to discharge, as described in Chapter 13. 8.5 References/1/ Kjeldsen, P. ; Christensen, T.H. 1996. Kemiske stoffers opførsel i jord og grundvand: Bind 2. Projekt om jord og grundvand fra Miljøstyrelsen nr. 20. Miljøstyrelsen. /2/ Massestrømsanalyse for nikkel. Miljøprojekt nr. 318, 1996. Udført af C. Lassen, T. Drivsholm og E. Hansen, COWI A/S og B. Rasmussen, K. Christiansen, I. Krüger A/S. /3/ GEUS (2004). Grundvandsovervågningen 2003. /4/ Miljøstyrelsen (2004). Punktkilder 2003. /5/ Miljøstyrelsen (1997). Miljøfremmede stoffer i overfladeafstrømning fra befæstede arealer. Miljøprojekt nr. 355. /6/ Bøgestrand, J. (red.) (2002): Vandløb 2001. NOVA 2003. Danmarks Miljøundersøgelser. - Faglig rapport fra DMU 422: 39 s. (elektronisk). /7/ DMU (2004). Søer 2003. Faglig rapport fra DMU nr. 516 (elektronisk).
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