Lead Smart guidelines developed by Port Pirie Environmental Health Centre to assist housing owners in Port Pirie to reduce lead exposure in the home.
Fishing around Port Pirie
Sediments in the Port Pirie River estuary and parts of Germein Bay near Port Pirie are contaminated with lead and other metals after more than 100 years of smelter operation. There is no safe level of lead exposure. Lead can be harmful to your health, particularly for young children and pregnant women. Eating seafood caught in the Port Pirie River estuary and nearby waters may be a source of lead exposure, which together with other sources of lead exposure around Port Pirie, will contribute to elevated blood lead levels. There are precautions you can take to prevent this source of lead exposure.
PIRSA have implemented a temporary fishing closure until 15 September 2021.
An investigation of potential health risks from consuming seafood caught in the Port Pirie River Estuary areas commenced in October 2020, with a number of species caught and tested. Results about this investigation were released by PIRSA on 22 December 2020 which indicated the closure is to stay in place while further investigation is carried out.
Why eating contaminated seafood a concern?
Pollutants such as lead, cadmium, arsenic and mercury can be absorbed by filter feeders such as shellfish and molluscs that live in or near contaminated sediments. Crabs and prawns (crustaceans) can ingest metals present in algae and other small organisms. These metals can build up (bio-accumulate) in the body tissues and organs of fish and can be passed through the food chain to other animals. Fish are known to accumulate a variety of toxins and metals especially in their bone.
Areas where sediment contamination levels are a concern
Previous studies have shown that shellfish collected from the Port Pirie River estuary and parts of Germein Bay contained lead at levels that exceed the maximum level of contaminants allowed in food set by Food Standards Australia and New Zealand (FSANZ).
A recent report published by the University of South Australia indicates that the levels of pollutants in marine and estuary sediments remain high. The report defines two zones where sediment contamination levels are a concern.
Zones where fishing is restricted
PIRSA have implemented a temporary fishing closure for Zone 1 and Zone 2 for a period of 12 months from 15 September 2020 until 15 September 2021. This is a precautionary closure.
- Zone 1 – high contamination – waters south and west of Weeroona Island Boat Ramp and including First Creek, Second Creek and Port Pirie River
- Zone 2 – intermediate contamination – waters in the Port Germein area, extending north and west from Weerona Island Boat Ramp
A map which includes navigational markers (PDF 268KB) has been produced showing you exactly where the closure is and where seafood has been tested.
Types of seafood restricted by zone
Waters south and west of Weeroona Island Boat Ramp and including First Creek, Second Creek and Port Pirie River.
- all species, including all molluscs, crustaceans and fish, must not be taken from this area. Catch and release fishing is permitted.
Waters in the Port Germein area, extending north and west from Weeroona Island Boat Ramp.
- bivalve molluscs eg. oysters, mussels, scallops and razorfish, must not be taken from this area.
Why is there a temporary fishing closure near the smelter?
Eating seafood that contains small amounts of lead or other metals can be a health risk. Lead can affect most organs including the brain. Seafood caught in and around Port Pirie may contain lead or other metals. For this reason, children and pregnant women should avoid eating locally-caught seafood because they are more vulnerable to the health effects of lead. This is especially important if local seafood makes up a large part of their diet. The temporary fishing closure is a precaution that will allow further assessment of the potential health risks associated with eating seafood caught in the Port Pirie area.
Cooking does not reduce the levels of lead and other metals in seafood.
This risk can be avoided by choosing commercially-produced seafood or seafood caught outside of the closure area.
Which seafood species have been tested?
The following were caught at multiple locations across Zone 1 and Zone 2 in October-November 2020 determined by availability. Samples of the meat, skeletons and shells of these species were sent for analysis to measure the levels of the metals lead, Mercury, Arsenic (inorganic) and Cadmium. Those tested included:
- Yellow-fin Whiting
- Yellow-eye Mullet
- Australian Herring (‘Tommy Ruff’)
- Australian Salmon
- Striped Trumpeter (‘Shitties)
- blue-swimmer crab
- bivalve molluscs (Australian Blue Mussels and Razorfish).
Sites where the seafood species were caught for testing?
The following seafood species were tested at the following locations:
- Zone 1
- Site 1 – First Creek Outlet (whiting, trumpeter, crab)
- Site 2 – Port Pirie Harbour (whiting, mullet, salmon, herring, crab, mussels)
- Site 3 – Weeroona Island (herring, trumpeter, crab)
- Zone 2
- Site 1 – Half-way between Port Germein and Weerona Isand (razorfish only)
- Site 2 – Port Germein (Razorfish ,mussels)
How is the investigation being done?
The first stage of this investigation was a preliminary screening assessment of the average (arithmetic mean) and maximum metal levels measured in seafood samples against screening criteria (now complete). The screening criteria used for this assessment are maximum levels (ML) set by Food Standards Australia and New Zealand (FSANZ). MLs are the maximum levels of contaminants permitted in specific foods sold commercially in Australia. For some species where Australian MLs are not available European guidelines were used.
For metal levels above the screening criteria, a more detailed assessment of risk is in progress to understand what amount of seafood consumed would cause people - particularly those most vulnerable (children, pregnant women and those with certain chronic diseases) to exceed health guidelines such as the current lead exposure investigation level recommended by the Australian National Health and Medical Research Council (NHMRC) if people have a blood lead level above 5 micrograms per decilitre (Frequently Asked Questions: NHMRC Review of blood lead level guidelines).
What do the seafood results show?
Results about this investigation were released by PIRSA on 22 December 2020 which indicated the closure is to stay in place while further investigation is carried out.
The average and maximum levels of mercury and arsenic (inorganic) in all species sampled were below the screening criteria. The average and/or maximum lead and cadmium levels in other species at some sampling sites were above the criteria. Details are available in the Port Pirie River Estuary Sampling Results (PDF 234KB)
What do the results mean?
Zone 1 only:
- Five species exceeded maximum permissible level of Lead in the commonly consumed portion – mussels, crabs, mullet, whiting, and striped trumpeter.
- Six species exceeded the maximum permissible level of Cadmium in the commonly consumed portion – mussels, crabs, mullet, whiting, striped trumpeter, and salmon.
Zone 1 and 2:
Both bivalve mollusc species (mussels & razorfish) tested exceeded maximum permissible levels of Lead as well as Cadmium in the commonly consumed portion.
Based on the data available, it is reasonable to expect that fin-fish, crabs and molluscs caught in Zone 1 and molluscs caught in Zone 2 have levels of Lead and Cadmium that may pose a risk to health and consumption should be avoided and minimised.
These results confirm that the precautionary approach to issue a closure to restrict consumption while investigation occurs was correct.
No advice can be given about metal levels in fish and crabs beyond zone 1 because sampling was not carried out in this survey.
This screening assessment also looked at the possible impact of seafood cooking practices on the level of metal being consumed. Overseas research has shown that cadmium can transfer from stores in crab organs and shells into crab meat after freezing, thawing and cooking. From the data available, metals were detected in the bones and heads of finfish and the shells and body organs of crabs that may transfer to edible portions (meat) and seafood stocks during food preparation and cooking to contribute to the overall ingestion of metals from eating seafood caught in this area.
What precautions should I take?
In most circumstances, seafood with metal levels below food safety guidelines are considered safe to eat. However, it is recognised that for some metals such as lead and arsenic there is no proven safe level of exposure and must be kept as low as possible (including exposure through our diet).
Avoiding dietary exposure to metals in food is particularly important for:
- people that are more vulnerable to the toxic health effects from metal exposure such as pregnant women, young children and people with chronic diseases such as diabetes and kidney disease that can be exacerbated by exposure to lead and cadmium; and
- people living in areas such as Port Pirie, Broken Hill, and Mount Isa where background levels of metal contamination as a result of industrial operations and therefore their potential daily exposure may be higher than most of the population; and
- people who may consume more locally-caught seafood than the average consumption of the general population over their lifetime such as recreational fishers. There can be health consequences associated with low levels of regular exposure over a long period of time especially for arsenic and lead but also for cadmium where there is a risk of build-up in the body over time. So even if metal levels are below food guidelines indicating a low exposure, there may be health consequences for people that regularly eat contaminated seafood over their lifetime.
Based on data:
— it is reasonable to expect fish caught in Zone 1 have levels of lead and cadmium that may pose a risk to health and consumption should be generally avoided or minimised.
— fish should not be consumed by pregnant women, young children and those with kidney disease or diabetes.
— crabs caught in Zone 1 should not be consumed because levels of lead and cadmium may pose a risk to health.
— bivalve molluscs such as Mussels and Razorfish taken from Zone 1 and Zone 2 should not be consumed because levels of lead and cadmium may pose a risk to health.
— seafood taken from Zone 1 and used to make stock or other seafood-based foods are an avoidable dose of lead.
There is no safe level of lead exposure. Lead can be harmful to your health, particularly for young children and pregnant women. For communities such as Port Pirie where residents are exposed to higher than background levels (20ppm) of lead. Eating seafood caught in the Port Pirie River estuary and nearby waters may be a source of lead exposure, which together with other sources of lead exposure around Port Pirie, will contribute to elevated blood lead levels. Locally caught seafood is an easily avoidable source of lead by choosing commercially-produced seafood or seafood caught outside of the closure area.
Baking and grilling whole fish, cooking whole crabs in shells and boiling fish bones and heads can release additional metals stored in these body parts into meat and stock which contributes to an avoidable dose of lead. There is limited data to examine the impact of cooking on metal levels in seafood caught in the Port Pirie River Estuary areas, but there is sufficient evidence from other locations that show that lead accumulates in fish bones and that cadmium can transfer from body organs into meat for consumption. Fish frames and crab shells and organs from species tested contain levels of lead and cadmium that may transfer to edible portions or stocks during cooking and contribute to consumption of metals by people eating seafood from this are.
Limitations of this advice
The preliminary screening assessment gives an indication of metal contamination of various species in the Port Pirie River Estuary area. How well this screening assessment and the size of the sample of animals available to be caught represents the risk to people who consume seafood from recreational fishing in the area is not fully known at this stage. Metal levels vary between species, locations and with size and maturity of marine organisms. Further understanding will come with the more detailed risk assessment to follow.
No advice can be given about metal levels in fish and crabs beyond zone 1 because sampling was not carried out in this survey. The data available cannot be used to advise if any species or any area of Zone 1 or Zone 2 has a different level of risk compared to other.
What are the health risks?
Lead in seafood
- Current advice from the Australian National Health and Medical Research Council (NHMRC, 2015) is that lead is not beneficial or necessary for human health and exposure should be minimised, and in any event, to a level where blood lead concentration does not exceed 5 micrograms per decilitre (µg/dL); and children and pregnant women are most at risk from adverse health effects of lead. Evidence for health effects of lead has been critically strengthened, leading NHMRC to revoke a ‘safe level’ guideline and publishing an action blood lead level of 5 µg/dL. There is now no ‘safe level’ of lead exposure.
- The central nervous system is the main target for lead toxicity in both adults and children - but it can have harmful effects on many organs and body functions.
- Long-term exposure to levels of lead (above 10 µg/dL blood lead levels) have been linked to with damaged nerve and brain function, blood cell production and renal function.
- Exposure to low levels of lead (between 5-9 µg/dL blood lead levels) has been associated with learning and behaviour problems, reduced IQ and academic performance and delayed puberty in children and increased blood pressure in adults.
- People with diabetes have a higher risk of adverse effects associated with the kidney. In pregnant women, high levels of exposure may cause decreased birth weight or miscarriage. In men it can damage the organs responsible for sperm production.
- At very high levels (above 70-100 µg/dL in children and above 100-120 µg/dL blood lead levels in adults), lead can severely damage brain and kidney function and ultimately cause death.
- Risk of health effects from lead exposure is highest for unborn babies, infants and children.
- The Port Pirie community has a high risk of daily lead exposure; there are few if any children who are not exposed to lead. Therefore the recommendation to avoid consuming locally-caught seafood that this survey shows contains lead - will reduce additional exposure to lead, above what typically occurs, which is especially important for children and pregnant women.
Cadmium in seafood
- Cadmium is not readily excreted from the body – it is released very slowly and can accumulate over time with ongoing exposure particularly in our kidneys. People who have eaten in the past or regularly eat seafood containing cadmium over time are at risk from cadmium build up in their bodies.
- Our body can tolerate some cadmium but if too much cadmium can contribute to kidney disease leading to renal failure.
- People with chronic diseases like diabetes and renal disease and older people are more vulnerable to the toxic effects of cadmium. Other long-term effects are fragile bones.
- Health effects in children are expected to be similar to the effects on kidneys and bone damage in adults.
- Cadmium is known to cause cancer in humans
Where can I go fishing?
All taking of species, including all molluscs, crustaceans and fish caught in Zone 1 is currently banned (catch and release fishing is permitted), while bivalve molluscs such as oysters, mussels, scallops and razorfish cannot be taken from Zone 2. Fishing is permitted outside of zone 1 and 2.