AVERAGE NUMBER OF PLASTIC DRINKS BOTTLES, CANS AND GLASS BOTTLES PER 500m SURVEY UNIT, AS COUNTED BY COASTWATCH SURVEYORS IN A GIVEN YEAR (1991 - 2017 ISLAND OF IRELAND)

Every year during the autumn Coastwatch Survey volunteers are requested to count a select number of small litter items in their chosen 500m survey unit(s).

Drinks containers have featured from the start in 1987 but initially it was a combined count. From 1991 on surveyors were asked to count drinks bottles, cans, glass bottles and tetra pack containers separately. Other drinks related items like lids and 6-pack holders were included some years. Counts are time consuming and surveyor feedback and requests for change are important. They are discussed annually in survey results and planning meetings. An option to only count in 100m of shore if running out of time or the area is too littered was introduced 4 years ago. Less than 10% of surveyors avail of it. A good mix of shore types are included in all surveys, but with some bias towards urban areas.

PERCENTAGE OF 500m SURVEY UNITS WHICH COASTWATCH SURVEYORS REPORTED WERE CLEANED IN THE WE WEEK PRIOR TO THEIR SURVEY (1991-2017 ISLAND OF IRELAND)

There has been a huge increase in volunteer and sponsored cleaning effort around our shores in the last 5 years. As the shore cleaning over time graph shows, number clean-ups reported during the week before the survey has trebled compared to pre 2013. This is the most likely reason for the observed reduction in drinks container litter. The figures suggest that a plateaux has been reached and that additional measures would be needed to reduce this ubiquitous litter.

AVERAGE NUMBER OF PLASTIC SHOPPING BAGS PER 500m SURVEY UNIT, AS COUNTED BY COASTWATCH SURVEYORS IN A GIVEN YEAR (1997 - 2017)

The Rep. of Ireland led the way in Europe in reducing plastic bag litter. Coastwatch HQ used the data from ±1000 survey sites per year and photos to underline the problem to government, supermarkets and citizens. With different actions considered in Coastwatch workshops, a bag tax seemed the most promising. With an Environment minister willing to spearhead it even in the face of initial shop hostility to the idea, the mood slowly swung. This was the first time citizen science data was used and read into Dail records – to support the passing of a waste management bill. With effect from 4 March 2002, a levy of 15 cent per bag was imposed at point of sale on the supply, by retailers, of plastic bags to customers. www.revenue.ie/en/tax/env-levy/environmental-levy-plastic-bags.html

The following year saw a huge reduction in the number of bags per 500m survey unit. In 2006 after several Coastwatchers flagged a change in Celtic tiger consumer attitude, we suggested a review of the levy. The current levy of 22 cent per plastic bag was introduced on 1 July, 2007. Since then all survey data showed consistent low count between 1.5 and 2.7 bags/survey unit. But plastic bags are still a problem. Even though the number of bags has reduced drastically in Ireland, if we look at the spread, plastic bags are still found in 40 to 55% of survey units. More work is needed to tackle this issue.

PERCENTAGE OF INFLOWS (STREAMS, PIPES & OTHER DISCHARGES) WHICH COASTWATCH SURVEYORS REPORTED
HAD VISIBLE SEWAGE, SEWAGE FUNGUS OR SANITARY LITTER (1989 - 2017 ISLAND OF IRELAND)

Coastwatch surveyors recorded sewage pollution and pollution indicators in any streams, ditches or pipes they crossed. The data gathered clearly shows that sewage pollution in inflows has reduced significantly over time.

Most of the remaining polluted inflows are concentrated in urban areas – either in one of the remaining urban pollution black spots where modern treatment plants are still at planning or building stage - or the odd small local discharge which was misconnected or omitted from the official sewer system.

N.B. Regarding sewage pollution on inflows, the wording of the question has been modified over the last few years. Until 2013 the questionnaire referred only to visible sewage and sewage fungus. In 2014 sanitary litter (i.e wet wipes) was added to this category and in 2017 ‘filamentous algae’ was appended.

PERCENTAGE OF 500m SURVEY UNITS WHICH COASTWATCH SURVEYORS REPORTED HAVING SANITARY LITTER (1989 - 2017 ISLAND OF IRELAND)

The number of areas where sanitary litter was reported on the shore over the last 25 years has decreased, but not as dramatically or as consistently as the sewage discharge from land data. Sanitary litter on the shore seems to be increasing in the last 3 years.

What has happened? Coastwatcher discussions have yielded three possible reasons:

1. An underreporting in early surveys as many school pupils were provided with a shortened survey form by teachers who were concerned about this level of detail and cut out the sanitary waste question and guide notes.
2. While sewage treatment has vastly improved over the last 30 years what goes into toilets has changed. Progressively more and more long lasting plastics are used in sanitary care. A fraction is flushed down the toilet, slips through sewage treatment as light fine material and then greets us on shores. As the indicators are so long lasting, they can spread and be recorded for a long time.
3. Wet wipes which have boomed in diversity and sales are a serious sewer system block risk and shown to be responsible for treatment and pump break downs. So while we have more treatment plants, these are not working as well as they should.

INFORMED OPINION OF SURVEYORS WHO KNEW THEIR AREA WELL REGARDING THE FREQUENCY OF SEWAGE POLLUTION INCIDENTS ON A GIVEN 500m SURVEY UNIT (1989 - 2017 ISLAND OF IRELAND)

Those who know their survey area well are asked to look back over the last year and indicate the frequency of sewage pollution.

Most relate this to the previous summer but longer time may also be taken into account in the surveyor answer. Results show that surveyors recount sewage pollution decreasing but this levels off.