Reaction mass of aluminium chloride, iron dichloride, magnesium chloride and manganese dichloride

Endpoint summary

Additional information

Iron

Iron is an essential trace element for fish and aquatic invertebrates and plants. The effects of iron sulphate on aquatic organisms in short-term tests are observed at nominal exposure concentrations in the range 1 – 1000 mg/L salt with the majority being in the range 10 – 100 mg/L. Effects arising from long-term exposures are observed at nominal concentrations in the order of 1 mg/L. At all of these concentrations it can be expected that, under the test conditions, most of the iron will be present as undissolved and precipitated ferric hydroxide. It is therefore highly likely that observed effects on fish and invertebrates will be due to smothering or clogging of the gills or respiratory membranes and effects on aquatic plants and algae will be due to impairment of photosynthesis by light interception. Growth of aquatic plants and algae can also be inhibited as a consequence of nutrient (phosphate) chelation.

Manganese

Manganese is a bioessential element, which is proven for a almost all organisms (ICMM 2007). Most of the manganese ecotoxicity data refer to ionized dissolved manganese and poor information exist on the effects of colloidal, particulate, and complexed species. Generally toxicities of metals in the latter forms are suggested to be lower.

The manganese toxicity is generally antagonized by calcium, which is evidenced by Reimer (1999) for daphnids (Daphnia magna), an amphipod (Hyalella azteca), a midge (Chironomus tentans), and fish (Oncorhynchus kisutch). Other authors confirmed the principle (Davies & Brinkman 1994, 1995), Lasier et al 2000). The effects were studied in the presence of 25 to 250 mg calcium carbonate per L, which corresponds to 0.25 to 2.5 mol/L or 10 to 100 mg calcium/L (MW CaCO3 = 100.0872 g/mol; MW Ca = 40.078 g/mol). As calcium is generally present under environmental conditions and is a constituent of the submission item itself (2.2 % of metal molarity) the upper ranges of the calcium dependent toxicity levels should be considered.

SSD / HC5(50%)

In order to assess in the impact of the manganese in the submission item the Species Sensitivity Distribution method as published by the WHO (2004 and 2005) is applied.

The ECHA (2008) guidance foresees the application of SSD for the derivation of HC5(50), i.e. the hazardous concentration to protect 95% of species with 50% as starting point for the PNEC derivation. According to Chapter R.10.3.1.3 on calculation of PNEC for freshwater using statistical extrapolation techniques, a minimal sample size (number of data) is required.

Confidence can be associated with a PNEC derived by statistical extrapolation if the database contains (validity criteria)

• at least 10 NOECs (preferably more than 15) for different species
• covering at least 8 taxonomic groups.

Acute to Chronic Extrapolation (ACR)

Unfortunately only acute toxicity threshold levels are available for manganese. Thus on one hand the application of the SSD seems not to be supported by the ECHA (2008) guidance. On the one hand the standard assessment factor approach, based on the lowest of the acute value, which cover each of the three standard trophic levels, and an assessment factor (AF) of 1000 would apply. As the lowest level obtained by Birge (1978), a 7 day LC50 on Narrow-mouthed toad (Gastrophryne carolinensis) tadpoles, is 1.4 mg/L, the resulting PNEC would be 1.4 µg/L. This is far below the natural background concentration of 34 µg/L (see discussion on environmental fate and pathways). Such PNEC and is for a bioessential element obviously nonsense.

On the other hand the ECHA (2008) guidance says “Deviations from these recommendations can be made, on a case-by-case basis”. Accordingly a SSD based on acute to chronic extrapolation seems justified as the standard derivation fails to reveal a meaningful value. The acute LC50 values were converted to chronic values using an acute to chronic ratio (ACR) of 2. Normally an ACR of 10 is used. However, because manganese is an essential element, a factor of 2 was used following ANZECC/ARMCANZ (2000) guidelines. Both these extrapolated acute values and chronic EC50s were then converted to chronic NOECs by applying a factor of 5, according to ANZECC/ARMCANZ (2000) guidelines. In other words, each acute LC50 was divided by 10 (i.e. 2 × 5) and each algal EC50 value (regarded as chronic) was divided by 5 prior to the species sensitivity distribution being undertaken. It would be better to use experimentally derived acute to chronic conversion factors, but these were not available for manganese.

The method applied in the CICAD 63 (WHO 2004 and 2005) delivers an estimated parameter in accordance with ECHA (2008). The HC5(50%) is the concentration corresponding with the point in the SSD profile below which 5% of the species occur together with a 50% confidence interval associated.

Taxonomic groups

The SSD can is based on 21 (acute) endpoints in freshwater some of them supported by more than one study result. For equivalent data on the same end-point and species, the geometric mean is used as the input value for the calculation. ECHA (2008) lists the required distribution criteria for a valid SSD as follows (in brackets the scientific names of the matching species):

1. A fish species frequently tested including salmonids (Oncorhynchus mykiss, Salmo trutta, Oncorhynchus kisutch)
2. A second family in the phylum Chordata i.e. fish from the families Cyprinidae (Carassius auratus), Heterpneustidae (Heteropneustes fossilis), Channidae (Channa punctatus), and Anabantidae, Colisa fasciatus), and an amphibian (Gastrophryne carolinensis)
3. A crustacean i.e. cladocerans (Ceriodaphnia dubia, Daphnia magna, Daphnia obtusa), a copepod (Cantho camptus spp.), an amphipod (Hyalella azteca, Crangonyx pseudogracilis), and an isopod (Asellus aquaticus)
4. An insect i.e. a midge (Chironomus tentans)
5. A family in a phylum other than Arthropoda or Chordata, i.e. Rotifera (Brachionus calyciflorus), and Annelida (Tubifex tubifex)
6. A family in any order of insect or any phylum not already represented, i.e. a ciliated protozoan (Spirostomum ambiguum)
7. Algae (Scenedesmus quadricauda, Pseudokirchneriella subcapitata); the latter one was formerly known under a different scientific name (Selenastrum capricornutum)
8. Higher plants: Data are lacking at the moment. It is considered unlikely that terrestrial plants are sensible to soil and/or sediment manganese as these environmental media are the major sink of manganese species. The natural background concentration is about 550 mg/kg soil d.w. (see discussion on environmental fate and pathways) and thus far above from the derived HC5(50%) value. For that reason the derivation of the HC5(50%) is considered a valid and representing a meaningful basis for the hazard assessment of the submission item on the basis of the manganese constituent. Confirming information can be obtained after dissemination as before no legal right of access was constituted for a major constituent. Timely recalculation using all available data is intended.

In conclusion and with regard to the ECHA (2008) criterion, a satisfactory number of different taxonomic groups is represented and the SSD is considered valid and conclusive.

Using the calculated chronic NOECs, the HC5(50), i.e. the hazardous concentration to protect 95% of species with 50% confidence - a “safe” value to ensure protection against chronic toxicity for most freshwater species in soft water was:

Hc5(50%) = 0.2 mg Mn/L

Twenty-one freshwater data were used from Table 3 (see section 7.2 of WHO 2004 and 2005), and from these data, chronic NOECs were calculated (see Table A-2 below). Non -standard test endpoints or endpoints of uncertain significance, such as total cell volume reduction and deformations, were not included. Geometric means of multiple test results from the same species over the same time period were calculated.

Table A-2 (WHO 2004 and 2005): Toxicity end-points and calculated chronic NOECs used in the derivation of a freshwater guidance value

Organism	Endpoint	Manganese concentration [mg/L]	Calculated chronic NOEC [mg/L]	Reference
(1) Fish species frequently tested
Salmonidae
Oncorhynchus mykiss	28 day LC50 (embryo-larval test)	2.9	0.3	Birge (1978)
Salmo trutta	96 h LC50	3.8	0.4	Davies & Brinkman (1994)
Oncorhynchus kisutch	96 h LC50	2.4	0.2	Reimer (1999)
(2) A second family in the phylum Chordata and/or an Amphibian
Cyprinidae
Carassius auratus	7 day LC50 (embryo-larval test)	8.2	0.8	Birge (1978)
Heterpneustidae
Heteropneustes fossilis	96 h LC50	3350	335	Garg et al (1989b)
Channidae
Channa punctatus	96 h LC50	3010	301	Garg et al (1989a)
Anabantidae
Colisa fasciatus	96 h LC50	3034	303.4	Geometric mean from 2850 mg/L (Agrawal & Srivastava 1980) and 3230 mg/L (Nath & Kumar 1988)
Amphibian
Gastrophryne carolinensis	7 day LC50 (embryo-larval test)	1.4	0.1	Birge (1978)
(3) A crustacean e.g. a cladoceran and/or a copepod, and/or an amphipod
Cladocera
Ceriodaphnia dubia	48 h EC50	7.2	0.7	Geometric mean from 9.1 mg/L Boucher & Watzin (1999), and 5.7–14.5 mg/L for hardness 26 to 184 mg CaCO3/L Lasier et al (2000)
Daphnia magna	48 h EC50 (immobilization)			Geometric mean from 9.8 mg/L (Biesinger & Christensen 1972), 8.3 mg/L (Khangarot & Ray 1989), range 0.8–76.3 mg/L for hardness 25 to 250 mg CaCO3/L Reimer (1999), range 0.8–76.3 mg/L for hardness 25 to 250 mg CaCO3/L Reimer (1999), range of mean values for six different clones 4.7–56.1 mg/L (Baird et al 1991), 2.0 mg/L (Sheedy et al 1991), 40 and 44 mg/L from chloride and lactate respectively (Bowmer et al 1998)
Daphnia obtusa	48 h EC50 (immobilization)	37.4	3.7	Sorvari & Sillanpää (1996)
Copepoda
Canthocamptus spp.	48 h EC50	54	5.4	Rao & Nath (1983)
Amphipoda
Hyalella azteca	96 h LC50	3.3	0.3	Geometric mean from range 3.6-31 mg/L for hardness 25 to 250 mg CaCO3/L Reimer (1999), and from 3.0-13.7 mg/L for hardness 26 to 184 mg CaCO3/L Lasier et al (2000)
Crangonyx pseudogracilis	96 h LC50	694	6.9	Martin & Holdich (1986)
Isopoda
Asellus aquaticus	96 h LC50	333	33.3	Martin & Holdich (1986)
(4) An insect e.g. a midge
Chironomus tentans	96 h LC50	5.8	0.6	Reimer (1999)
(5) A family in a phylum other than Arthropoda or Chordata
Rotifera
Brachionus calyciflorus	24 h LC 50	38.7	3.9	Couillard et al (1989)
Annelida
Tubifex tubifex	96 h LC50	168	16.8	Geometric mean from 170.6 mg/L (Khangarot 1991) and range 164.6–275.7 mg/L for temperatures from 15 to 30 °C (Rathore & Khangarot 2002)
(6) A family in any order of insect or any phylum not already represented
Protozoa
Spirostomum ambiguum	24 h LC50	148	14.8	Nalecz-Jawecki & Sawicki (1998)
(7) Algae
Scenedesmus quadricauda	12 day EC50 (growth inhibition)	5	1	Fargašová et al (1999)
Pseudokirchneriella subcapitata-formerly known under a different scientific name (Selenastrum capricornutum	72 h EC50 (growth inhibition)	8.3	1.7	Reimer (1999)

 

 

Table 3: Disregarded endpoints on toxicity of manganese to aquatic species (WHO 2004 and 2005)

Organism	Endpoint	Manganese concentration [mg/L]	Reference	Reason
(1) Fish species frequently tested
Salmonids
Oncorhynchus mykiss	96 h LC50	4.8	Davies & Brinkman (1994)	Value from 28 day LC50 of an embryo-larval test used
(2) A second family in the phylum Chordata and/or an Amphibian
Macquaria novemaculeata	96 h LC5	100	WHO (2004 and 2005), Australian studies provided after cut-off date	Marine species
(3) A crustacean e.g. a cladoceran and/or a copepod, and/or an amphipod
Cladocera
Daphnia magna	21 day LC50	5.7	Biesinger & Christensen (1972)	Geometric mean from seven 48 h LC50 used
	24 h LC50 (immobilization)	56	Sorvari & Sillanpää (1996)
Amphipoda
Crangonyx pseudogracilis	24 h LC50 (immobilization)	1389	Martin & Holdich (1986)	96 h LC 50 from same study used
Isopoda
Asellus aquaticus	24 h LC50	771	Martin & Holdich (1986)	96 h LC 50 from same study used
Anostraca
Artemia salina	48 h LC50	51.8	Gajbhiye & Hirota (1990)	Marine species
Copepoda
Nitocra spinipes	96 h LC50	70	Bengtsson (1978)	Marine species
Decapoda
Penaeus monodon	96 h LC50	26.1	WHO (2004 and 2005), Australian studies provided after cut-off date	Marine species
(5) A family in a phylum other than Arthropoda or Chordata
Tubifex tubifex	48 h LC50	208.1	Khangarot (1991)	96 h LC 50 from same study used
		171.4–350 for temperatures from 15 to 30 °C	Rathore & Khangarot (2002)
Mollusca
Crassostrea virginica	48 h LC50	16	Calabrese et al (1973)	Marine species
Mya arenaria	168 h LC50	3000	Eisler (1977)
Mytilus edulis	48 h EC50 (abnormal larvae)	30	Morgan et al (1986)
Saccostrea glomerata	60 h NOEC (larval abnormalities)	1	WHO (2004 and 2005), Australian studies provided after cut-off date
Echinoderma
Heliocidaris tuberculata	72 h EC50 (abnormal larvae)	5.2 (NOEC = 1.3 mg/L)	Doyle et al (2003)	Marine species
(6) A family in any order of insect or any phylum not already represented
Protozoa
Spirostomum ambiguum	24 h EC50 (deformations)	92.8	Nalecz-Jawecki & Sawicki (1998)	LC50 from same study used
Tetrahymena pyriformis	1 h EC50 (non-specific esterase inhibition)	27	Bogaerts et al (1998)	Not an LC50
	9 h EC50 (proliferation rate inhibition)	210
(7) Algae
Alga
Scenedesmus quadricauda	12 day EC50 (total chlorophyll reduction)	1.9	Fargašová et al (1999)	Growth inhibition value from same study used
Pseudokirchneriella subcapitata-formerly known under a different scientific name (Selenastrum capricornutum	14 day EC50 (total cell volume reduction)	3.1	Christensen et al (1979)	Inappropriate endpoint
Chlorella stigmatophora	21 day EC50 (total cell volume reduction)	50	Christensen et al (1979)	Marine species
Diatomeae
Ditylum brightwelii	5 day EC50 (growth inhibition)	1.5	Canterford & Canterford (1980)	Marine species
Nitzschia closterium	96 h EC50 (growth inhibition)	25.7	Rosko & Rachlin (1975)	Marine species
	72 h NOEC (growth rate inhibition)	18	WHO (2004 and 2005), Australian studies provided after cut-off date
Asterionella japonica	72-h EC50 (growth inhibition)	4.9	Fisher & Jones (1981)	Marine species

 

NOECs below the HC5(50%) level

According to ECHA (2008) the NOEC values below the 5% of the SSD need to be discussed in the risk assessment report. It is of particular importance that not all NOECs from one taxonomic group range below or close to the derived HC5(50%) of 0.2 (WHO 2004 and 2005). The Narrow-mouthed toad (Gastrophryne carolinensis)is the most sensitive species. No further amphibian data exist. The real hazard to amphibians is concluded to be less than expressed by the figures from Birge (1978) due to (1) the bioessential nature of manganese, (2) the generally known adaptation of biota to metals, (3) the artificial laboratory situation when testing Mn+2 solutions without organic carbon, less calcium than in natural surface waters, and the missing suspended particular matter and sediment, which contribute to the reduction of manganese bioavailability. Thus the manganese bioavailability under environmental conditions may be significantly lower and the organisms may be less sensitive. Furthermore the application of the full ACR may be discussed as the test duration of 7 days is subacute and embryo-larval stages were used.

Some fish species seem quite sensitive. The NOEC calculated for the Coho salmon (Oncorhynchus kisutch) is at the same concentration as the derived HC5(50%). On the other hand the highest tolerance level is reported from a fish (Colisa fasciatus).

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• Bowmer CT, Hooftman RN, Hanstveit AO, Venderbosch PWM,van der Hoeven N (1998).The ecotoxicity and the biodegradability of lactic acid, alkyl lactate esters and lactate salts. Chemosphere 37(7):1317–1333.
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• Christensen ER, Scherfig J, Dixon PS (1979).Effects of manganese, copper and lead on Selenastrum capricornutum and Chlorella stigmatophora . Water Research 13(1):79–92.
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• Fisher NS, Jones GJ (1981). Heavy metals and marine phytoplankton: Correlation of toxicity and sulfhydryl-binding. Journal of Phycology 17:108–111.
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• Garg VK,,(1989a). Hematological parameters in fish Channa punctatus under the stress of manganese. Environment & Ecology 7(3):752–755.
• Garg VK,,(1989b). Manganese induced haematological and biochemical anomalies in Heteropneustes fossilis. Journal of Environmental Biology 10(4):349–353.
• ICMM International Concil of Mining and Metals (2007). MERAG: Metals Environmental Risk Assessment Guidance. Self-published London, UK. ISBN: 978-0-9553591-2-5. 80 p
• Khangarot BS, Ray PK (1989). Investigation of correlation between physicochemical properties of metals and their toxicity to the water flea Daphnia magna Straus. Ecotoxicology and Environmental Safety 18(2):109–120.
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Aluminium

As there are several short term studies available and one long-term fish test and a long-term derived EC10 for algae, an assessment factor of 50 can be used. The long-term fish study gave the lowest NOEC of 13 µg/L, which would be used for the PNEC derivation. This would lead to a PNEC freshwater of 13/50 = 0.26 µg dissolved Al /L. For the marine environment an assessment factor of 500 is to be used. This would lead to a PNEC marine of 13/500 = 0.026 µg dissolved Al /L.

These values are likely to be over conservative estimates as the available evidence suggests that toxicity declines at environmental relevant pH values, as does the availability of dissolved aluminium species.

It is important to note that were these equilibrium concentrations truly reflect the toxicity of aluminium in solution they would place it alongside, or more toxic than, some of the most potent toxic chemicals that are known. Such a view could clearly not be sustained given the ubiquity of aluminium in all its various forms in the environment.

It is therefore reasonable to assume that a small proportion of the added aluminium in the tests without analysis was present in the form of dissolved aluminium – the majority being present as precipitate or complex. This is confirmed by chemical analysis performed in several other studies. Only a very small amount of the added aluminium compound was dissolved. In some studies it was even below detection limit. Secondary effects arising from the presence of the precipitate together with possible pH reduction are likely to have contributed to the effects observed in the tests. This assumption is substantiated by observations noted in some of the test reports.

Aluminium salts may present a toxic hazard to environmental species under specific conditions. For example, it is possible that aluminium salts could have toxic effects in circumstances where the following conditions apply and persist:

• pH is low (< 5.5)
• oxygen content is very low
• organic matter content is low
• natural background concentrations of aluminium are low.

Such conditions would need to result in dissolved aluminium concentrations in the order of magnitude where toxicity occurs and would not be expected to arise from the industrial production and use patterns for these aluminium salts.

Aluminium species are naturally common throughout the environment. Measured background concentrations and Regulatory Standards for aluminium provide a useful context for considering the results of this assessment:

The concentration of aluminium in natural waters can vary significantly depending on various physicochemical and mineralogical factors. Dissolved aluminium concentrations in waters with near-neutral pH values usually range from 0.001 to 0.05 mg/L but rise to 0.5–1 mg/L in more acidic waters or water rich in organic matter. At the extreme acidity of waters affected by acid mine drainage, dissolved aluminium concentrations of up to 90 mg/L have been measured (WHO 1997).

The main source of background concentrations of aluminium in the aqueous environment are soil minerals such as gibbsite (Al(OH)3) and jurbanite (AlSO4(OH)•5H2O), especially in poorly buffered watersheds (Driscoll & Schecher 1990, Campbell et al 1992, Kram et al 1995). In more buffered watersheds, a solid-phase humic sorbent in soil is involved in the release of aluminium (Cronan et al 1986, Bertsch 1990, Cronan and Schofield 1990, Cronan et al 1990, Seip et al 1990, Taugbol & Seip 1994, Lee et al 1995, Rustad & Cronan 1995). (Text taken from Environment Canada and Health Canada 2010, Exposure Characterisation).

Organisms present in waters with higher aluminium concentrations (present in e.g. suspended sediment) are adapted to tolerate such conditions. The extent to which organisms will be affected by further additions of aluminium will be determined by their ecology and physiology – some organisms can tolerate elevated levels of suspended material and surface sediment, others cannot.

Responses to effects arising from other secondary factors such as lowered pH and nutrient complexation will also be dependent upon the susceptibility of resident organisms to perturbations in these parameters and the characteristics of the receiving environment (e.g. buffering capacity and background nutrient concentrations).

In conclusion because of the high and varying background concentrations and the very low PNEC, which is derived when standard guideline is followed for PNEC derivation, it is not considered accurate and realistic to follow the standard approach.

Any concentration of aluminium in water that can be considered as stable can only be due to the complexing effects of natural constituents in the water, bearing in mind that the amount in water will already be at saturation. This concentration will vary with location. It is not possible to consider that any addition to the aquatic compartment can be stable, and therefore no PNEC can be set for fresh and marine water.

A lab study is not able to assess the inherent complexity of the environment. But that environment will be saturated under all realistic conditions with aluminium in the speciated form appropriate to the conditions, and organisms are evolutionarily-adapted to it, and rely on it. Any release of aluminium which the ecosystem cannot adapt to will result in gross physical effects, outside the scope of REACH.

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