A total of 1203 pieces of plastic and other pollutants stopped from entering the stormwater system & reaching the Waitamata Harbour.
Industries such as supermarkets have a high pedestrian foot count and busy loading zones which can lead to high litter loading.
In New Zealand, Foodstuffs is the largest grocery distributor and the largest supermarket chain. Back in 2016 we approached the company to conduct a trial of the LittaTrap to measure the type and quantity of pollutants that would enter the stormwater system via the stormdrains on their busy sites. We worked with the Foodstuffs North Island team to identify trial sites.
TRIAL SITES
Two trial sites were chosen and an audit was conducted to determine the most appropriate catch basins.. The catch basins on each site were chosen to be representative of all the pits on sites; some were chosen for an anticipated high loading (e.g loading zones), and the others chosen for low loading rates. The loading would vary from pit to pit, and clean to clean. This is influenced by climate and physical influences, such as rain, wind and traffic volumes. Five catch basins were monitored in total.
METHODOLOGY
Enviropod monitored and reported on a monthly basis providing quantitative and qualitative data on the type and quantity of gross pollutants captured by the LittaTrap.
DATA COLLECTION
Each catch basin was emptied of its contents, photographed and then sorted using a standardized litter collection datasheet that is in use throughout the country. The data for each catch basin was collated for close to 6 months (168 days) and the quantity of each pollutant was recorded.
RESULTS
A total of 1203 pieces of plastic and other gross pollutants were stopped from entering the stormwater system and making reaching the Waitamata Harbour. This is an average of 523 pieces of litter per pit per year.
75% of the litter collected was plastic (Soft Plastic, Hard Plastic, Food wrappers, Cigarette butts & Polystyrene).
The biggest single source of pollutant was cigarette filters. Cigarettes made up 20% of the total litter caught ( 243 butts)
OBSERVATIONS
The catch basins monitored were only a small percentage of catch basins on each site. If the data is extrapolated out Trial Site One could stop 7322 pieces of plastic and other litter from reaching the waterways over a 12-month period. Trial Site Two could stop 6799 pieces of plastic and other litter over a 12-month period.
SUMMARY
Foodstuffs have 421 retail outlets across the North Island. These include New Worlds, PaknSaves, Liquorlands and Four Squares. If 4 x LittaTaps were installed at each store, the group could potentially stop approximately 900,000 pieces of plastic & litter a year from entering the marine environment via the storm drains every year.
