MILK We drink it - surely it’s ok for fish? Milk spilt into waterways has a serious impact by killing fish and other aquatic life through suffocation. How does milk kill fish? Milk contains large amounts of proteins, sugars and fats, which are a valuable food source for naturally occurring aquatic organisms including bacteria, fungi and algae. Usually the limited food supply in the water reduces or restricts the population and growth of these naturally occurring organisms. A milk spill however is an unlimited food source, and this results in a population explosion. As the organisms break down the milk they use oxygen from the water. As the population increases, the oxygen level decreases leaving none for the fish that are present, causing them to suffocate.

WASTE OI L We all know waste oil is a pollutant: Around 30 million litres of waste oil is generated in New Zealand every year. Much of this is recycled however an unknown quantity ends up in rivers and the sea. One litre of waste oil can cover an area of water the size of an Olympic size swimming pool and could contaminate 1,000,000 litres of drinking water How does waste oil affect the environment? Waste oil can directly poison birds, fish and other organisms. Waste oil can also form a layer on the surface of waterways preventing oxygen and sunlight from entering affecting both aquatic plants and animals. Heavy metals and other contaminants in waste oil can accumulate within aquatic plants and animals slowing/stopping their growth or killing them over time.

PAINT What harm does paint cause in waterways? The particles from the paint damage the gills of fish and make it very difficult for them to get oxygen. Paint also prevents light from entering the water and this affects plant growth and makes it hard for fish to find food. But its “water” based. What’s the problem? Water-based does not mean environmentally friendly. Any type of paint can cause serious environmental damage by poisoning or suffocating aquatic animals or altering habitats. Enamel paints (oil-based paints) contain highly toxic solvents which have a serious impact on waterways. Old lead based paints can be harmful to people as well as animals. The lead can also build up in the sediment in rivers and estuaries which will remain toxic for hundreds of years.

DETERGENT

It’s just a bit of soapy water – what’s the harm? Detergents, including biodegradable ones can directly poison aquatic animals, or make them more susceptible to pollutants and disease. How much? An estimated 10,000L of detergent enters Tauranga’s waterways and the sea every year from car washing. That’s almost 200L (enough to fill ten buckets) every weekend – just from car washing! That’s enough detergent in one year that a person could use it to wash their dishes once a day for over 500,000 years! How does detergent affect aquatic life? Detergents damage gills and destroy the external mucus layers that protect fish from bacteria and parasites. Even very small amounts of detergent will kill fish eggs. Phosphates in detergents can also lead to algal blooms. These algal blooms can release toxins and will seriously deplete oxygen in waterways which suffocates fish and other aquatic life.

COOKING FATS AND OILS

Why is fat and oil bad for the environment? Fats and oils can directly poison or suffocate fish and aquatic life. They can also block light from waterways and seriously deplete oxygen levels as they break down causing asphyxiation of aquatic life. Cooking fat and oil is bad for drains! Don’t tip fat or oil down the sink or any other drains! Fats and oils can solidify in pipes and cause blockages. A blocked sewer line could flood your house with sewage or pollute local streams or the sea. A blocked storm water pipe could cause serious flooding.

MUD AND DIRT Its only dirty water – what’s the problem? Sediment is a pollutant. It causes much more harm than most people realise. Sediment can kill aquatic animals, or make it difficult for them to breathe or find food. It can choke waterways and carry more harmful pollutants too. And of course nobody wants to swim or fish in muddy water. How does dirt cause environmental damage? Sediment can strip waterways of food sources for aquatic animals and smother eggs which impacts on the long term survival of species. Sediment also fills in estuaries and can carry other more harmful pollutants such as heavy metals. Sediment in waterways also has an impact on water treatment and supply and may increase the cost of drinking water.

FOOD & DRINK Fish don’t like beer! Alcohol, milk, blood, meat products, food scraps and food industry processing wastes are all harmful to aquatic ecosystems. They do not “feed fish” but will poison them or remove oxygen from the water resulting in suffocation. Alcoholic beverages and processing wastes contain toxins that can directly poison aquatic animals. Food waste suffocates aquatic life! Food waste of any kind will remove oxygen from waterways as it breaks down, and make waterways unhealthy for people. Food waste, even in very small amounts can have an impact and over time may kill off particular species and change the food web within an ecosystem.

EFFLUENT Makes good fertilizer right? Stock effluent that flows or leaches into streams and ground water is a serious pollution problem. Effluent contains extremely high levels of nutrients which seriously reduce the oxygen content of waterways as they break down. Nutrients also increase algal and weed growth the breakdown of which further reduces the oxygen levels of waterways. Reduced oxygen causes asphyxiation of fish and other aquatic life. Sewage from sewer line breaks, blockages and overflows will cause serious problems in waterways as it contains effluent and a wide range of other pollutants such as cleaning chemicals, food waste and personal hygiene products. Effluent is not healthy for waterways OR people! Any effluent discharged into waterways will carry pathogens and bacteria that are harmful to humans. Drinking water may be contaminated, waterways will be unsafe for swimming and shellfish may become toxic to humans.

CEMENT WASH-WATER

Concrete causes burns just like acid does! Lime is a major component of cement and is found in all concrete products. Cement slurry or water that comes into contact with unset concrete or concrete dust will be highly toxic to aquatic life. Concrete wastewater has a pH of 12 -13 (pH of freshwater is 6-7) and is as toxic as oven cleaner or bleach. Wet cement can cause serious burns to people and will burn the gills and skin of fish causing death. A single bucket of concrete wastewater is toxic enough to kill hundreds of fish. Cement blocks pipes too. Cement washed into drains can harden and cause blockages. This causes damage that often results in flooding or sewer overflows.

RUBBISH Tidy Kiwis? Everyday thousands of items of rubbish are discarded or are washed into streams and the sea. This includes food wrappers, plastic bags, glass, paper, plastic bottles, cans, cigarette butts and much else besides. Some of these items may take over 500 years to break down. Rubbish is a killer! Rubbish can be toxic and can directly poison aquatic animals or make waterways too polluted to support any life. It is estimated that up to 100,000 marine mammals (dolphins, seals, whales etc) and up to 1,000,000 sea birds are killed every year worldwide after becoming tangled in or from injesting rubbish like plastic bags, plastic tape, and old fishing lines and nets. Rubbish - Its not only ugly, it’s a health hazard too. Sharp objects like glass can cause injury and other rubbish such as food and medical waste can cause infection and disease. Rubbish makes water unhealthy for drinking or for swimming in. Rubbish also blocks drains and waterways which can cause flooding.

C CIGARETTE BUTTS

Its only one cigarette butt… Every single day in Tauranga thousands of cigarette butts are littered. People flick them out of their cars, stub them out on the footpath or throw them directly into drains. Most of these wash into streams or the sea. How many? In Tauranga around 60,000 cigarette butts are littered each day. An estimated 23, 816, 250 cigarette butts each year that end up in streams and the sea. That’s an astounding 4 tonnes of dirty cigarette butts, enough to fill ten rubbish trucks. If you lined up end to end, all the cigarette butts littered by New Zealand smokers in one year, the line would stretch around the earth 35 times!!! They can’t be that harmful though…can they? Cigarette filters are made of cellulose acetate and they can take over 3 years to break down. The amount of nicotine in 200 cigarette butts is enough to kill a human being - think what it does to aquatic animals. Cigarette butts leach toxic chemicals like cadmium, lead and arsenic into our waterways. Cigarette butts can also poison fish and birds that ingest them.

ROAD RUNOFF What’s really on our roads…. Vehicles cause serious pollution and although your car may only cause a very small amount it all adds up! An average road surface is likely to be contaminated with dirt, grease, oil, petrol, diesel, brake fluid, hydraulic oil, antifreeze, rubber, detergent, food scraps, cigarette butts, rubbish, organic waste, heavy metals like zinc, copper, chromium, lead and any number of other contaminants. Where does it go when it rains? All the pollutants are washed directly into streams, rivers, groundwater systems, lakes and the sea. There is usually no treatment of road runoff. This adds up to many tonnes of pollutants entering our waterways every year. These pollutants have a wide range of impacts on ecosystems but can cause serious long term damage as they slowly accumulate in marine organisms and sediments.

BIODEGRADABLE PRODUCTS

“BIODEGRADABLE” does not mean “environmentally friendly”! Most people assume a “biodegradable” product will quickly break down and therefore cause little harm to the environment – this is not necessarily the case. Biodegradable simply means that the product will be broken down over time by environmental processes. For example ethanol is biodegradable but also highly toxic. Many “biodegradable” products such as detergents and other cleaners are toxic and initially damage the environment in the same way as non-biodegradable products. Some “biodegradable” products take months or years to degrade and can remove oxygen from waterways and may even produce more harmful substances as they break down. For example the toxic pesticide DDT biodegrades to the compounds DDD and DDE, both of which are more toxic than the original DDT itself. Biodegradable or not - Keep all chemicals, wastes and rubbish out of stormwater drains, waterways and the sea.