1.2 Chemical Contamination

Impact of chemical contamination will take place when heavy metals (Cd, Cr, Cu, Zn, Hg, Cr, etc.) or nitrogen (N, nitrite NO₂, nitrate NO₃, ammonia NH₄) or phosphate (PO₄), cyanide (CN), organics containing phenol, PAH (polycyclic aromatic hydrocarbons), etc. having concentrations higher than the allowed levels. These chemicals are generally in wastes from steel mills, metal/mineral processing and metal plating plants.

Serious contamination will take place in a water environment if these liquid effluents are discharged without proper treatment leaving levels in the wastewater  higher than those allowed for. In some cases inadequate dilution of effluents could also lead to serious contamination, especially when they are allowed to be discharged directly to sea via ocean outfalls.

1.3  Effect of El Ninõ

Some critics have also suggested that the rising temperature caused by El Ninõ is also causing fish kill. However rising temperature alone would not be the reason causing fish kill on a massive scale. The rising temperature of seawater around the world in the first 4 months of 2016 (on average at 1.2 deg C announced lately by NASA) could not alone be blamed for the fish kill. An increase in temperature of 2-5 deg C could only decrease the oxygen levels in sea water to 4-5 ppm at most.

Several incidents of fish kill on a large scale have been seen around the world. Contaminated seawater with high levels of N and P discharged into sea causing algae bloom in warm water was the main cause of fish kill when over 300 whales died last year along the Chilean coastline.

Source: http://www.abc.net.au/news/2016-05-04/wave-of-dead-sea-creatures-hits-chile-beaches/7384576

Algae blooms have also taken place in Australia, up to 20 scenarios a year over the last 40 years. These incidents have been associated with lower oxygen levels, changing in seawater temperature, salinity or pH and are generally localised along the shorelines. High nitrogen and phosphate are generally high in these incidents. In one incident (17-26 Sept 2012) an orange-light brown algae bloom took place in a lagoon near Sydney killing around 300 fish (bream, sea mullet and eels). “An analysis of the bloom water indicated the presence of a compound with the retention time of a Luteophanol A- (a complex organic compound containing fragments of amphibinol, a toxin), which caused up to 87% decrease in cell viability in an assay of fish gill cells. The fish deaths may have been attributed to the low dissolved oxygen, and the presence of a Luteophanol A-like compound may have contributed” is the conclusion reached by the investigators.

Source: Murray, S., Kohli, G.S., Farrell, H., Spiers, Z.B., Place, A.R., Dorantes-Arnda, J.J., Ruszczyk, J., 2015. A fish kill associated with a bloom of Amphidinium carterae in a coastal lagoon in Sydney, Australia Harmful Algae 49 (2015), 19–28.

2. TOXICITY CAUSING  FISH KILL

Toxicity is from two sources:

1. Chemical sources: coming from heavy metals and organic chemicals such as DDT, herbicides, pesticides. N and P chemicals do not have high toxicity to fish but their presence is promoting algae blooms, depleting oxygen in water to fatal levels for fish,
2. Biochemical sources: from toxins released by algae during bloom.

2.1   Chemical sources

Chemical sources causing harm to fish include both inorganic and organic contaminants.

Heavy metals when existing at levels higher than those permitted (lethal levels) will kill fish and other marine organisms. Therefore many countries around the world set very tight specifications on the levels of these heavy metals allowed to be discharged to sea. The lethal concentration (LC) which causes death to fish varies from one type to another and also on the fish size and age.

The LC levels (in mg heavy metal/L of water or ppm) are generally measured in a laboratory at different times such as 24, 48, 72 and 96 hours and classified as LC50 or LC100  as levels at which 50 or
100% of the fish tested would die). For example:

1. LC50 at 96 h is 0.24 ppm Cu and 0.8 ppm Zn for Cobia fish
   Source: Le Quang Dung, Nguyen Manh Cuong, Nguyen Thanh Huyen and Nguyen Duc Cu, 2005. Acute toxicity test to determine the effect of copper, zinc and cyanide on Cobia (Rachycentron Canadum), Australasian J. of Ecotoxicology, 11, 163-166.
2. LC50 at 24 h is 0.16 ppm Hg and ~ 2ppm Cu for mollusc (shell fish, oysters, etc.)
   Source: Ramarikritinan, C.., Chandurvelan, R., Kumaraguru, A.K., 2012. Toxicity of metals: Cu, Pb, Cd, Hg and Zn on marine mollusc, Indian J. of Marine Sci., 41(2), 141-145.

Oysters can sustain high levels of heavy metal uptake, up to 2000 ppm Zn, 6-7000 ppm Ca, P and Mg.

Source: Kumar, K.M., Sajwan, K.S., Richardson, J.P., Kannan, K., 2008. Contamination profiles of heavy metals, organochlorine pesticides, polycyclic aromatic hydrocarbons and alkylphenols in sediment and oyster collected from marsh/estuarine Savannah GA, USA, Marine Pollution Bulletin, 56, 136–162.

Inorganic nitrogen (ammonia NH₄, nitrite NO₂, nitrate NO₃ ) and organic nitrogen (amine) can contaminate a water environment.  Inorganic nitrogen can change from one form to another and finally could also be converted to nitrogen gas, escaping to the atmosphere via denitrification process. Organic N (amine) however binds strongly with heavy metals and is very stable and insoluble in water.

Phosphate also has many forms in water (Fig. 2), including PO₄^3- (soluble reactive phosphate SRP, <0.003 micron), organic phosphate (phosphonate) and solid precipitate (>0.2 microns) when combined with Ca, Mg, Fe, etc settled to the bottom of the water body. Analyses for phosphate therefore have to include both forms of phosphate in a water sample. Only when in a soluble form that phosphate would promote algae bloom. However phosphate can also change from the solid form to soluble form. Organic phosphate can only be converted to inorganic phosphate via a biological reaction.

Fig. 2: Conversion process of different forms of phosphate in water

Source: Shaw, G.R., Moore, D.P., Garnett, C. (2004). Eutrophication and algae blooms, Environmental and Ecological Chemistry, Vol 2.

Organic contaminants such as endosulfan (organochlorines) chlorpyrifos (organophosphate) found in herbicides, pesticides, etc, are toxic for fish at 1 ppb (part per billion) levels.

Source Table 3.4.1 - Australian & NZ guidelines for fresh and marine water quality-2000: https:///www.environment.gov.au/system/files/resources/53cda9ea-7ec2-49d4-af29-d1dde09e96ef/files/nwqms-guidelines-4-vol1.pdf).

2.2  Biological Sources

Toxicity caused by biological sources cause harms to both fish and humans. Table 1 below shows several types of toxic syndrome to humans and fish caused by toxins created by organisms (algae) found in water. About 60-80 phytoplanktons are known to have toxicity harmful to both fish and humans. Known harmful toxins are also listed in Table 1 and Fig. 3.

Note: PSP: Paralytic shellfish poisoning, NSP: Neurotoxic shellfish poisoning, CFP: ciguatoxin fish poisoning, ASP: Amnesic shellfish poisoning, DSP: Diarrhetic shellfish poisoning,

Source: Frances M. Van Dolah,2000. Marine Algal Toxins: Origins, Health Effects, and Their Increased Occurrence EnvironHealth Perspect 1 08(suppi 1):1 33-141 (2000).

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1637787/

Fig. 3: Known toxins (A) Salitoxin, (B) Brevetoxin, (C) Ciguatoxins, (D) Okadaic aicd, (E) Domoic acid.

Source: Frances M. Van Dolah,2000. Marine Algal Toxins: Origins, Health Effects, and Their Increased
Occurrence EnvironHealth Perspect 1 08(suppi 1):1 33-141 (2000). http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1637787/

3.  INTEGRATED  STEEL MILLS AND THEIR WASTES

3.1 Iron and Steel Making Process

Sources:
https://www.epa.gov/sites/production/files/2015-12/documents/ironsteel.pdf
http://www.steel.org/making-steel/how-its-made/processes/how-a-blast-furnace-works.aspx
http://www.ilocis.org/documents/chpt73e.htm

The iron and steel making process (Fig. 4) has the following stages:

1.  Stage 1: Coke making (coke has >80% carbon) from coal. This stage will generate particulates, CO/CO₂, ammonia (NH₃), NOx (NO/NO₂), SOx (SO₂/SO₃), polycyclic aromatic hydrocarbons (PAH) containing phenol. Waste water from this stage will contain BOD (biological oxygen demand), suspended solids, SS, cyanide(CN),  ammonia (NH₃), phenol/PAH,


2. Stage 2: Iron ore Sintering to produce sinters having particle diameters of ~20-50 mm at temperature >1000 oC. Gas emission includes SOx, NOx, HF, PAH,


3. Stage 3: Calcination of dolomite to produce CaO (lime). Gas emission includes particulates, CO₂, NOx (NO/NO₂), SOx (SO₂/SO₃),


4. Stage 4: Iron making from CaO, iron ore sinters and coke in a Blast Furnace at ~2000 oC. Gas emission includes H2S (this is the reason some smell could be detected in the air near a steel mill), CO/CO₂, SOx, NOx, ZnO, PAH. Waste water used for cooling of blast furnaces has SS, BOD, ammonia (NH₃), cyanide (CN), sulphate (SO₄), chloride (Cl) and sludge. The blast furnace also generates iron slag to be disposed in nearby area.


5. Stage 5: Steel making from molten iron from a blast furnace using a Basic Oxygen Furnace (BOF) at a temperature ~ 1700 oC, by blasting oxygen at 120-150 atm into the direct molten mass. Gas emission and waste water generated  will be the same like the iron making process. This stage also produces steel slag.


6. Stage 6: Casting. Casting of the molten steel into moulds to produce steel blocks (10 m long x 1 m width x 0.3 m thick). Wastes include oils/grease, particulates and sludge,


7. Stage 7: Hot and Cold Rolling to produce steel plates (~0.5 mm) and rolls. This stage will produce little gas emission including  SOx, NOx. Solid wastes include hematite Fe₂O₃ from oxidised steel. Wastewater includes SS, BOD, chromate (Cr(VI)), phosphate, sulphate and HCl used in the steel pickling stage (to dissolve the steel rust).

The steel making process from an integrated steel mill and wastes generated  from its operation are shown in Fig, 4 below.

Fig. 4: Schematic diagram showing the integrated iron & steel making process with its Casting and Rolling mills

Source: http://www.ilocis.org/documents/chpt73e.htm

In general to produce 1 metric tonne of steel, a mill requires 1.5 tonne of iron ore, 0.5-0.65 tonnes of coal and coke, 0.25 tonne of dolomite and 1.8-2.0 m3 of air. The mill will produce 0.2-0.4 tonne of
slag and 50 kg of particulates. A 1 million tonne/year steel production plant will also generate 10,000 m3 of waste water/day for treatment.

The diagram in Fig. 5 shows the main operations at BHP NZ Steel mill producing different rolled products including cold rolled steel, galvanised steel and pickled and oiled coil.

Source:
McDonald,  T.S., Dance K., Rolling and surface coating of steel:
http://nzic.org.nz/ChemProcesses/metals/8B.pdf

The Rolling Mill with two sections (Hot Strip and Cold Strip Mill) will produce the following wastes
(from points identified by RED arrows on the diagram):

1. Iron oxide (reddish brown hematite Fe₂O₃) produced by air oxidation of the steel slab
   surface (1-2 mm thick) at high temperature is removed by the descaling unit (hydraulic scale breaker) using high pressure water (100 MPa) while the hot steel slab (1000 oC) (10m long x 0.4m thick x 1.5m width) has been rolled into thin sheets and travelled back and forth during the operation of the reversing roughing mill. This sludge is supposed to be filtered off and disposed in landfills.


2. The waste effluent from the pickling line is supposed to be from the hydrochloric acid (HCl) dissolving the remaining iron oxide layer (5-8 microns thick) forming soluble Fe(III) chloride in a 10% HCl.
   
   This effluent is usually treated  by a third party to be used as fertilisers.


3. Oil and grease waste during the oiling of the coils to prevent corrosion.

Fig. 5: Schematic of a Steel Rolling Mill

Part of the Rolling Mill plant is to produce galvanised or aluminised steel products. In Fig. 6 below the cold rolled coil is cleaned and degreased before being re-heated  and dipped into a bath of molten zinc or zinc alloy to form a coating for corrosion protection. The coated strip is then pulled through a chromate spray to convert the Zn metal coating to zinc oxide and iron to iron oxide to prevent corrosion.

The chromating section is a potential source of Cr contamination.

Fig.6: Schematic of a zinc galvanised section of the Rolling Mill.

Aluminium and antimony are usually added to the zinc bath to control its fluidity and zinc crystal size. The waste from this section will contain chromate (hexavalent Cr(VI)) which  is very toxic and has to be treated  before discharge. Potential contamination comes from chromate in this section.

Few plants also produce painted products (such as ColorSteel from BHP NZ Steel) where chemicals such as phosphate, caustic NaOH, chromic acid are used for cleaning and surface oxidising.

In summary, potential wastes from the Rolling Mill are:

1. Iron oxide (most probably a reddish brown hematite Fe₂O₃) in the sludge, which has to be filtered off and disposed in landfills,


2. Hexavalent Cr(VI) in the washwater from the zinc galvanising section,


3. Soluble Fe(III) chloride from the pickling bath,


4. Oil and grease from the oil bath during hot stripping.

3.2 Formosa Steel Mill

The Formosa steel mill will produce different steel products from iron ore, limestone, coke
(produced from the coke oven using metallurgical coal) and other additives. The plant is supposed to produce up to 22.5 million tonnes (MT) of steel in full production.

Source: Wikipedia:  en.wikipedia.org/wiki/Formosa_Ha_Tinh_Steel

According to published information from Wiki, the project will be implemented in several stages
with "Phase 1- Blast furnace iron production was scheduled to begin in 2016, with two blast furnaces at the plant having a total production capacity of 7.5 MT pa; approximately 6 MT were for flat steel production, and 1.5 MT for rebar and other rolled steels. Two further expansion phases, were planned to increase production to 15 MT and then 22.5 MT pa”. The steel mill produced its first steel roll product in late December 2015.

Source:  Vietnamese steel manufacturers warn about “Formosa danger. 13 January 2016: http://english.vietnamnet.vn/fms/business/149852/vietnamese-steel-manufacturers-warn-about-formosa-danger.html

Iron ore is to be imported from the Australian Fortescue Metals Group’s Iron Ore Bridge project in Western Australia of which Formosa owns approximately a third with an investment of $ 1.15 billion earlier.

(Source: Fortescue executes $A 1.15 billion with Formosa - Company announcement:
http://fmgl.com.au/media/1604/1246243724.pdf

The Formosa plant is currently operating at a lower production rate well below capacity and only in the Hot/Cold Rolling section. The main discharge at this stage is wastewater  which has reached ~10.000 m3/day. Other stages of the production are still being implemented and when finalised to reach maximum capacity, the plant will discharge ~46.000 m3/day.

According to Tuoi Tre newspaper Formosa has imported over 300 tonnes of chemicals in the last few months. These chemicals have been used for pipe coating, anti-corrosion treatment, etc.

Source: http://tuoitre.vn/tin/chinh-tri-xa-hoi/20160424/vu-ca-chet-formosa-nhap-hoa-chat-cuc-doc-suc-xa-duong-ong/1089748.html

Anti-corrosion chemicals are generally amine or phosphate (zinc or sodium phosphate), organic phosphate. Antifungal reagents are oxidants such as chlorine gas (Cl2) or hydrogen peroxide H2O2. To treat chromate (Cr6+) a reductant such as NaNO2, FeSO4, etc, is used.

3.2 Wastes Generated  from an Integrated Steel Mill

Wastes generated  from this operation which can cause impact to the environment (Fig. 7) include (a)
wastewater/liquid effluents, (b) air emissions and (c) iron and steel slags.

Fig. 7: Iron and steel making process and its wastes

Source: http://www.ilocis.org/documents/chpt73e.htm

Iron and steel making has been in existence for a long time. Improvement of the technology is mainly for waste processing. The following table (Table 2 shows the different types of wastes generated  from an integrated steel mill.

Table 2: Wastes (gas, wastewater  and solid) generated  by an integrated steel mill according to industry benchmark

Source: World Bank-International Finance Corporation (IFC), 2007. Environmental, Health and Safety Guidelines - Integrated Steel Mills (from 30 April 2007):

http://www.ifc.org/wps/wcm/connect/0b9c2500488558848064d26a6515bb18/Final%2B-%2BIntegrated%2BSteel%2BMills.pdf?MOD=AJPERES&id=1323161945237

Different methods have been used by steel mills around the world to treat their wastes. Wastewater could be discharged into sea, as long as it is treated  properly to meet legal standards, as exemplified by the Skinninggrove steelworks in North Yorkshire, UK. POSCO, one of the largest steel mills in Korea has 4 ocean outfalls discharging wastes from its steel mills in Pohang.

Source: Mike Morgan, 2011. Steel firm invests in waste treatment plant in Skinningrove, Gazette Live, 4 october 2011:

http://www.gazettelive.co.uk/news/local-news/steel-firm-invests-waste-treatment-3680028
https://tethys.pnnl.gov/sites/default/files/publications/Environmental_Management_in_Korea.pdf

In some cases dilution with seawater can be done first before the diluted effluent streams are disposed, a practice also followed by the mining/mineral processing industry.

Unlike other mills, Bluescope Steel (Wollongong, Australia) recycles its wastewater  for re-use. The mill produces 2.7 million metric tonne of steel products/year and relies on Sydney Water to treat 20,000 m3/year of wastewater  for recycling and re-use.

Source:
https://www.sydneywater.com.au/web/groups/publicwebcontent/documents/document/zgrf/mdq2/~edisp/dd_046307.pdf

The treatment process employed by Sydney Water includes:

• Filtration of suspended solids,


• Biological treatment to remove N and P,


• Coagulation of fine solids using polymer and filtration,


• Microfiltration to remove 0.1-10 micron particles and bacteria,


• Reverse osmosis to remove dissolve salts and heavy metals


• Precipitation of heavy metals and removal to < 1ppm levels using lime or NaOH and sulphide, followed by filtration to remove precipitates for disposal.

Source: https://www.epa.gov/sites/production/files/2015-12/documents/ironsteel.pdf

The treatment of air emission from a steel mill requires:

1. Post combustion of flue gas to convert CO gas and other organic chemicals containing phenol (PAH) to CO₂


2. Use of electrostatic precipitators or bag filters to remove particulates of <10 microns size,


3. Removal of SOx using  FGD (flue gas desulphurisation) and NOx via SCR (selective catalytic reduction) using ammonia to convert NOx gas to nitrogen and water vapour.
   The recovery of SOx gas (>98%) is also based on a Dry Process or (CaO+water) process to convert SOx gas to sulphuric acid. A catalytic bed containing V₂O₅ is used to convert SO₂ to SO₃. The gypsum (calcium sulphate) product is used for wall board making.


4. Other metal oxides (Zn, As, etc.) are collected in the above steps and treated as wastewater.

The treated  gas only containing CO2 and water vapour can then be discharged to the atmosphere. The solid particulate collected has to be tested using TCLP (Toxicity Characteristics Leaching Procedures) to determine its leachability before being disposed of in landfills or re-used in cement making.

3.2.2 Treatment of Wastewater

The treatment of wastewater  in general involves:

1. Removal of all heavy metals using lime or sulphide precipitation to reach concentration levels <1 ppm. Several countries are now banning the disposal of the heavy metal precipitates in landfills due to the fact that metal sulphide can be in the long term oxidised by bacteria to release acid and metal back to the environment (acid mine drainage)


2. The toxic chromate Cr(VI) has to be converted to Cr(III) using a reductant and precipitates as Cr(III) hydroxide for removal from the wastewater,


3. N and P chemicals have to be destroyed by biological treatment whereas phosphate can be precipitated as(Ca, Al, Fe)_x(OH)_yPO₄ disposed in landfills or reprocessed as fertilisers,


4. Advanced techniques such as reverse osmosis and microfiltration are also used at a cost to remove all heavy metals, dissolved salts, etc to produce high-quality water for re-use.


5. The pickled liquor (containing iron (II) choride in HCl) is sold to a third party for reprocessing.

3.2.3 Treatment of Slag

Slags (mainly silicate of Ca, Fe) are produced from a steel mill during iron and steel making. Slags can be reprocessed to be used in road making or cement production.

4.     SPECIFICATIONS AND PRACTICE OF EFFLUENT DISCHARGE TO SEA FROM AN INTEGRATED  STEEL MILL

4.1 Standards Recommended by the World Bank

The conditions of discharges (air, effluents, sludge and solid wastes) of an integrated steel mill as recommended  by the World Bank International Finance Corporation (IFC) guidelines are listed in Tables 3-4. The new guidelines effective since 30 April 2007 have superseded  the previous version (July 1998).

Source: World Bank-International Finance Corporation (IFC), 2007. Environmental, Health and Safety Guidelines - Integrated Steel Mills (from 30 April 2007):

http://www.ifc.org/wps/wcm/connect/0b9c2500488558848064d26a6515bb18/Final%2B-%2BIntegrated%2BSteel%2BMills.pdf?MOD=AJPERES&id=1323161945237

4.1 Vietnam Standards

Source:  /www.env.go.jp/air/tech/ine/asia/vietnam/files/law/QCVN%2005-2013.pdf

4.1.1 Standards for Air Emission

Several sets of standards (QCVN – Quy Chuẩn Việt Nam) for air emission were declared by the Vietnam Ministry of Resource and Environment to specify the limits of discharge from steel production plants. Table 5 compares the standards recommended  by the World bank-IFC and the parameters used for the calculations of the discharge limits set by QCVN.

Table 5: Comparison of World bank-IFC recommended  standards for air emission and parameters C used for the calculations of the limits set by the Vietnamese standards (QCVN) for plants starting from 17 November 2013.

The limits of discharges set by QCVN for all of the above contaminants are calculated from parameter C (column 3 and 4) using the formula:

Cmax = C x Kp x Kv

Kp is the index describing the sources of discharge(0,8-1,0) and Kp is the index for different regions air emission is discharged to (0,6-1,4), with lower figures for populated areas and higher numbers for country and mountainous areas.

4.1.2 Standards for Wastewater

The Vietnam’s national standard for discharging effluents from steel mills (QCVN 522-2013/BTNMT) issued on 25 October 2013 seems to follow the old standard from World Bank/IFC guidelines (1998-2007) which have stopped being used from 30 April 2007. Table 6 compares the 3 standards including (a) old WB-IFC from 1998-2007 (third column), (b) the most updated WB-IFC 30 April 2007 (fourth column) and (c) QCVN 522-2013/BTNMT (filth column). The updated version of WB-IFC recommends more contaminants to be monitored compared to the old data. The Vietnam standard for discharge of effluents from steel mills to Non-Drinking Water Sources does not match with the current World Bank-IFC guidelines for discharge as shown in Table 6.

http://www.ifc.org/wps/wcm/connect/0b9c2500488558848064d26a6515bb18/Final%2B-%2BIntegrated%2BSteel%2BMills.pdf?MOD=AJPERES&id=1323161945237

https:/www.env.go.jp/air/tech/ine/asia/vietnam/files/law/QCVN%2005-2013.pdf

Table 6: Comparison of standard specifications for discharging effluents recommended  by the WB- IFC guidelines and the Vietnam standard for Parameter C.

(mg/L = ppm = 1000 ppb = 1000 microgram/L)

The QCVN limits for discharges (Cmax) are to be calculated from the parameter C (column 5 Table 6 above) from the formula Cmax = C x Kq x Kf where Kq is the index (0.6-1.2) corresponding to the water flowrate (m3/s) or volume (m3) of the target into which wastewater  is discharged to and Kf (0.9-1.2) is the flowrate of the wastewater  discharge (m3/day).

In the new version of WB-IFC guidelines (2007) other contaminants including total N, P, F, sulphide, Fe and polycyclic aromatic hydrocarbon (PAH) are added. These are the chemicals commonly discharged now from a modern steel mill.

4.3 Comparison of Limits Set for Discharges from Steel Mills and Seawater Standards

The concentration limits (Cmax) for all contaminants could be calculated from parameter C of the above and are tabulated below in Table 7, comparing them with the limits for seawater of 3 different zones (Zone 1: Zone with fish/sea product farms and marine protection park, Zone 2: Zone used for recreation and water sport, Zone 3: others)

Table 7: Limits of contaminants (Cmax) calculated using the formula Cmax = C x Kq x Kf, with Kq = 1 cho for target sources having flowrates of 50-200 m3/s and Kf = 0.9 for wastewater  discharge having flowrates > 5.000 m3/day) and comparison with limits set for seawater in 3 different zones.

The Cmax tabled above (Column 7) was calculated using  Kq= 1 for target sources (rivers, creeks, etc.) with flowrates in the range 50-200 m3/s. If slower than 50 m3/s  Kq = 0,9 and if flowrates are in the range  200-500 m3/s, Kq = 1.1. In this whole range, the variation of Cmax is within +/- 15%.

The following issues are of concern:

1. Limits of contaminants in seawater vary from one zone to another, with stricter conditions applied for near fish farms (Zone 1) and recreation areas (Zone 2). However discharge limits (Cmax) are much higher than the seawater standards,


2. There is no limit for P in the QCVN standard for wastewater  discharge from steel mills (limit from World Bank-IFC is 2 ppm P) and that in seawater is 0.3-0.5 ppm P,


3. The limit for total N in QCVN standard for wastewater  discharge from steel mills is 60 ppm, higher than that from World Bank-IFC at 30 ppm, whereas there is no limit of total N in seawater.


4. Limits for heavy metals and other contaminants (cyanide, pheonol, etc.) are generally higher in Vietnam Standard (QCVN) compared to ANZECC (Appendix) or US-EPA,

As an example, for mercury the Criterion Maximum Concentration (CMC) and Criterion Continuous Concentration (CCC) for seawater are 1.80 and 0.94 ppb, respectively (CMC and CCC are levels at which are harmful to human health on short term and long term basis, respectively) according to the USA-EPA regulations, similar to the Trigger Levels set by ANZECC (Appendix) . For fresh water these levels are even lower.

Source: National Recommended Water Quality Criteria - Aquatic Life Criteria Table:
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-aquatic-life-criteria-table

The standards set by the US-EPA and ANZECC (see example in the Appendix) also have more details on limits set for organic contaminants or for N (with total N and all components of ammonia, NO2/NO3   and P (total P and filterable reactive phosphate). To also monitor the algae bloom, both the US-EPA and ANZECC sets the levels of chlorophyll-a in the range 1-5 microgram/L (ppb).

As an example (Appendix) the limits for trigger levels of marine environment in the South East
Australia are set at Total P = 25 ppb (0.025 mg/L) of which  FRP (filterable reactive phosphate) = 10 ppb, Total N = 120 ppb, of which NOx (nitrite/nitrate) = 5 ppb and NH4 15 ppb.

The Vietnam Standard (QCVN) for seawater tabulated in Table 7 is nowhere near those set by the ANZECC standards, with inadequate limits (or no limits) set for N, P and chlorophyll-a. This is the area of concern and should be addressed by the agencies responsible for the setting of QCVN standard.

The Vietnam standard of wastewater  discharges stipulated by the VNQCVN 52:2013/BTNMT protocol does not seem to be as strict as the WB-IFC (2007 onward) guidelines. The reason why phosphate, total nitrogen (including amine, nitrate, nitrite and ammonia) is introduced for example is to stop metal processing plants discharging without treatment the latest chemicals which are stable and harmful to the environment, especially  if they are organic. These organic groups (amine and organic phosphate) when bound with heavy metals such as Cu, Ni, Zn, Cd, Pb, etc. are more stable in the environment and their treatment inside the plant during processing is not easily done. When discharge these more harmful chemicals (such as Cu phosphonate, with phosphonate now used as anticorrosion reagents) are very stable and do not decompose compared to inorganic heavy metal such as free Cu ions, which may convert to Cu(OH)Cl (copper hydroxyl-chloride) precipitate and settles to the bottom of the sea. These insoluble heavy metal-chelated organics will float in the sea water and remain so for a long time.

4.4 Methods for Discharging Wastewater into Sea

Unlike in USA or Australia where all Environmental Impact Studies (EIS) have to be presented for public scrutiny, there is no disclosure on any information on how the discharge method is conducted for metal processing plants in Vietnam. As an example it is known that the Formosa steel mill is discharging up to 46,000 m3/day (at maximum plant capacity), using marine outfall placed on the seabed 1.7 km from shore. One has to wonder how the design was made to take into account the dilution required for the discharge which has much higher limits for contaminants than those trigger levels (limits) set for seawater.

The limits set for discharge in some cases are 10-20 times higher than those allowed for seawater set by the Vietnam Standards (QCVN). To reach the targeted limits quickly so not to harm fish, the flowrates and volumes of seawater around the point of discharge have to be much higher than those allowed for discharge.

As an example at 46,000 m3/day discharge using pipes of 1m2 cross section area, the flowrate of discharge is 0.53 m/s at the point of discharge. To reduce this 10 times, a flowrate of seawater of 5.3 m/s is required if pipes of the same cross section area are used. It is better for this flow to be combined with the wastewater  before discharge to sea as it can be easily monitored, controlled and varied according to the plant discharge. The discharge using marine outfall is not easily monitored with unknown volume and flowrates of the seawater around the point of discharge, which also varies from year to year or one season to another.

The main issue here is that even by following the Vietnam national standard of discharge (ie. VNQCVN 52:2013/BTNMT protocol) a steel mill discharge might still cause significant environmental contamination. One should look at the current flow of the sea in the region surrounding the steel mill, especially at the point of discharge. The dispersion of the effluent, if treated  properly according to standard might not be enough to reduce the contaminants to the levels safe for fish.

The flow of the ocean surrounding the point of discharge should be known for this dilution, especially at this high rate of discharge. Using flow modelling experts can decide whether this direct discharge is good enough for contaminant to meet the seawater standards. One has to remember that the discharge levels specified by regulators have to be governed by the efficiency of the waste treatment method. If this is still not achievable (for example to remove Hg from the effluents to 1 ppb, which is almost impossible technically at this stage) dilution inside the plant has to be enforced.

One of the main reasons for establishing legally-forceable limits of heavy metals for the disposal of effluents is that ocean fish and other aquatic organisms will uptake the heavy metals and other contaminants. Following the food chain which finally ends up at dinner tables, this would further affect human health, if people intake a much higher doses than those recommended  by health authorities. The notorious Minamata disease, a neurological syndrome caused by severe mercury poisoning of over 2,200 people due to the contamination of fish and shellfish in the bay of Minamata city by methyl-mercury is a constant reminder for all of the danger of heavy metal contamination (Minamata disease: https://en.wikipedia.org/wiki/Minamata_disease).

Different fish and aquatic organisms uptake different levels of heavy metals under different contamination conditions. Tiger prawns from farms in Sabah, North Borneo using contaminated water have been found to uptake few ppm heavy metals of all types, including mercury whereas oysters found in Savannah, Georgia (USA) were found to contain up to 6,800 ppm P, Mg and 2,000 ppm Zn (ppm: mg contaminants/kg of oysters).

Sources:

Alturiqi, A.S., Albedair, L.A., 2012. Evaluation of some heavy metals in certain fish, meat and meat products in Saudi Arabian markets, Egyptian Journal of Aquatic Research, 38, 45–49.

Hashmia, M.I., Mustafab S., Tariqa, S.A., 2002. Heavy metal concentrations in water and tiger prawn (Penaeusmonodon) from grow-out farms in Sabah, North Borneo, Food Chemistry, 79 (2), 151–156.

Kumar, K.M., Sajwan, K.S., Richaardson, J.P., Kannan, K., 2008. Contamination profiles of heavy metals, organochlorine pesticides, polycyclic aromatic hydrocarbons and alkylphenols in sediment and oyster collected from marsh/estuarine Savannah GA, USA, Marine Pollution Bulletin, 56, 136–162

Hauser-Davisa, R.A., Bordon, I.C.A, Oliveirac, T.F., Lourenc¸ R., Ziolli, O., 2016. Metal bioaccumulation in edible target tissues of mullet (Mugil liza) from a tropical bay in Southeastern Brazil, Journal of Trace Elements in Medicine and Biology, 36, 38–4.

These levels should be below those recommended  by the WHO-FAO and seem to be varying from one country to another according to a compilation from WHO-FAO.  As an example, The Food Safety Australia & New Zealand recommends the acceptable concentration levels (ppm or mg contaminants/kg of fish or shellfish) in fish and shellfish to be within 2 ppm Cd, 0.5 ppm Hg, 1 ppm As and 2 ppm Pb, whereas those recommended  by WHO-FAO are 30 ppm Cu, 1 ppm Cd and 30 ppm Zn in fish.

Sources:
FAO (1983). Compilation of legal limits for hazardous substance in fish and fishery products (Food and agricultural organization). FAO fishery circular, No. 464, pp. 5–100.

Food Safety Australia & New Zealand (FSANZ), http://ecan.govt.nz/publications/Reports/heavy-metals-fish-shellfish-2012-survey.pdf

The critical issue is not just related to the instant (and/or continuous) fish kill from which dead fish of different sizes large and small, mollusc, etc. have been deposited along the coastal shores of many provinces in Central Vietnam from Ha Tinh to Thua Thien-Hue. The plankton at the lowest scale of the food chain would have also been destroyed and the surviving fish or those coming from the other areas with seasonal current flows would have nothing to feed on. It would take some time for plankton to be reformed and fish can feed again to replenish stock for fishermen to catch.

The whole food chain from the sea in this region would definitely be affected in the long term. Formosa therefore should consider taking seawater into its steel mill and pre-dilute the effluents several folds before discharge. Another option is to merge the effluents with another flow of seawater before pumping the combined flow to the sea. By then, underwater  or surface discharge would not be the issue.

Contamination of the aquatic surroundings by steel mills and metal processing plants around the world is not new. Even for Australia with vast areas away from population has not escaped disastrous accidents and subsequently the high cost of remediation. Examples of contaminations of aquatic environment, including those caused by Electrolytic Zinc in Tasmania in the 1970’s and BHP (now BHP Billiton) in Newcastle in the 2000’s have shown that it would take a long time and cost money to fix the problems if happening. Over a long period of time the disposal of jarosite into the sea around Electrolytic Zinc plant has been the normal practice which caused oysters and mussels in the region to adsorb extremely high levels of zinc, cadmium and other base metals. BHP has already spent over $A 650 million to remediate the Hunter River and its surrounding land since its closure in
1999.

Source:
M. Kelly and I. Kirwood, BHP steelworks site – A pollution time bomb, 1 Sept 2012 :
http://www.theherald.com.au/story/291785/bhp-steelworks-site-pollution-time-bomb/

R. Beckmann, Oysters and zinc – The Derwent revisited ,Eco50, Summer 1987:
http://www.ecosmagazine.com/?act=view_file&file_id=EC50p3.pdf

What has been learned from EZ in Tasmania is that by following the levels of heavy metals existing in oysters and mussels, one can trace and monitor the level of contamination taking place by surrounding metal processing plants. Australia has adopted this technique subsequently to follow up on potential contaminations as evaluation of seawater is not always easy especially  if the time factor is ignored.

CONCLUSIONS

Fish kill on a large scale has not happened previously in Vietnam. The latest incident in which fish kill has taken place over a wide area covering over 200 km of the coastline in Central Vietnam has called for authorities and the industry to find an urgent remedy for this disaster. Of concern is the livelihood of fishermen living along the coastline which now is facing an uncertain future.

What has caused this tragic incident to happen ?. No one at this stage is giving a realistic and reliable explanation backed by strong data and the reason for fish kill, either from contaminated seawater or algae bloom. A concerted effort by experts in the field covering many disciplines is required to find a proper answer for this problem and to devise a strategy to avoid disasters as these to happen again. The sluggish response by the authority and lack of transparency have created doubts on the limited information reported by newspapers on the critical issues involved. Taking a serious approach is not an easy task. Government agencies have to enforce strict monitoring of the environment we are living in. Most steel mills now have to apply an appropriate corporate social responsibility model (such as those in the EU) and to maintain a right attitude to respect the planet earth, of which we are all sharing.

The recommendations by authorities such as EPA and ANZECC on how to monitor seawater quality should be used as guidelines for Vietnam to adopt. The following ket parameter should be monitored:

1. Concentration of chlorophyll-a, cell numbers) and species composition,


2. Total phosphate and components (soluble and solid P).


3. Total nitrogen and components including ammonia (NH₄⁺) and dissolved NOx(nitrite NO₂^- và nitrate NO₃^-)


4. Heavy metals and organic chemicals commonly used by metal processing plants,


5. Characteristics of the sea around the industrial zones, including flow rate,volume, mixing/diffusion, temperature, turbidity), total suspended solids, etc.

OTHER REFERENCES

1. (a) WHO Guidelines  for drinking water quality, 2011:
   http://apps.who.int/iris/bitstream/10665/44584/1/9789241548151_eng.pdf


2. Australian Drinking Water Guidelines, updated Feb 2016:
   /www.nhmrc.gov.au/_files_nhmrc/file/publications/nhmrc_adwg_6_february_2016.pdf


3. USA National Primary Drinking Water Regulations (US-EPA), updated Jan 2016:
   https://www.epa.gov/ground-water-and-drinking-water/table-regulated-drinking-water-contaminants


4. Ramarikritinan, C.., Chandurvelan, R., Kumaraguru, A.K., 2012. Toxicity of metals: Cu, Pb, Cd, Hg and Zn on marine mollusc, Indian J. of Marine Sci., 41(2), 141-145.


5. Antifouling agents. Wikipedia: (https://en.wikipedia.org/wiki/Anti-fouling_paint


6. Anticorrosion agents. Wikipedia: https://en.wikipedia.org/wiki/Corrosion_inhibitor


7. Heubach - Anticorrosives from A to Z:
   http://www.heubachcolor.de/fileadmin/documents/downloads/Brochures/Anticorrosives.pdf


8. Red tide. Wikipedia: https://en.wikipedia.org/wiki/Red_tide


9. Shaala, N.M.A., Ismail, S.Z.Z., Azmai, M.N.A., Mohamat-Yusuff. F., 2015. Lethal concentration 50(LC50) and effects of Diuron on morphology of brine shrimp Artemia salina (Branchiopoda: Anostraca) Nauplii, International Conference on Environmental Forensics, 30, 279 – 284.


10. Best Available Techniques (BAT) Reference Document for iron and Steel production (2013) – EU-JRC Refererence Report. http://eippcb.jrc.ec.europa.eu/reference/BREF/IS_Adopted_03_2012.pdf

SOURCES OF STANDARDS FOR EFFLUENT DISPOSAL

Australian Standard for Sampling and Analysis for Wastewater. Soils and Wastes (2009):
http://www.epa.vic.gov.au/~/media/Publications/IWRG701.pdf

APHA (US-EPA Approved Standard Method): https://www.standardmethods.org/

Quy Chuẩn Kỹ Thuật ChấtThải Công Nghiệp: Nước và Khí Thải từ Sản Xuất Sắt Thép, Bùn Thải từ Xử Lý Nước, v.v: (52-2013-QCVN, 2005-2013):

http://congtyphongviet.com/Images_upload/files/52_2013_QCVN_ky-thuat-nuoc-thai-cong-nghiep-san-xuat-thep.pdf

http://www.env.go.jp/air/tech/ine/asia/vietnam/files/law/QCVN%2005-2013.pdf

Quy Chuẩn Kỹ Thuật Nước Thải Công Nghiệp: Giấy, Dệt May, vv– Thủ Đô Hanoi (2014):
http://moj.gov.vn/vbpq/Lists/Vn%20bn%20php%20lut/Attachments/29135/VanBanGoc_51.2014.TT.BTNMT.pdf

Quy Trình Quan Trắc Nước Mặt Luc Địa (2011): http://www.slideshare.net/newtechco/thng-t-s-292011ttbtnmt-quy-nh-quy-trnh-quan-trc-nc-mt-lc-a

Quy Chuẩn Kỹ Thuật Quốc Gia về Chất Lượng Nước biển

http://www.iph.org.vn/attachments/article/1010/QCVN%2010.2015_Nuoc%20bien.pdf

Tam Tran

Professor
Department of Energy & Resources Engineering
Chonnam National University
Gwangju

SOUTH KOREA

APPENDIX:

Trigger Levels set by ANZECC for South East Australia

Trigger Levels set by ANZECC for South East Australia