Macrolitter along a highly frequented roadway
Description
Road runoff constitutes a potential non-point source of pollution as roadside ditches may connect land-based sources to waterway. Here is a dataset of macrolitter collected in a retention pond from a portion of 800 m of a highly frequented highway in Nantes, France (Cheviré Bridge: Lat. 47.1849; Long. -1.6144). Roadtraffic is exclusively dedicated to motorists with a constant traffic of around 90,000 vehicles per day (10% heavy vehicles) and no pedestrians are allowed. Macrolitter > 1 cm were collected (n = 36,439 items) over one year (August 2020/July 2021) during 10 field campaigns, covering the second lockdown related to COVID-19 pandemic. Macrolitter were classified according to TSG-ML/OSPAR (238 categories). 84% items were plastics by count. Dry mass of each category was also reported for a total mass of 88.5 kg (60% of plastics by mass). Categories are gathered relative to their main material type including artificial polymes (i.e. plastics), rubber, textile, paper/cardboard, manufactured wood, metal, glass/ceramic and other. Top 10 items represent 92% by count of the total items and Top 10 items by mass represent 72% of the total mass. The most specific items featuring in both Top 10 are plastic fragments (31% by count and 24% by mass), EPS fragments (17% by count and 4% by count), foam packaging (11% by count and 6% by mass), Cardboards (6% by count and 13% by mass), wood fragments (4% by count and 6% by mass), industrial plastic sheets (1% by count and 5% by mass) and rubber fragments(1% by count and 4% by mass). Cigarette butts, paper fragments and sweet wrappers are only featuring in the Top 10 by count and represent respectively 18%, 3% and 2%. Other textiles, plastic bags and metal fragments are only featuring in the Top 10 by mass and represent respectively 4%, 4% and 3%. Those data are relevant for studies aiming to estimate macrolitter fluxes related to roadsides together with their sources. Although individual protections like single use masks were found, no specific trends were highlighted during the lockdown.
Files
Steps to reproduce
1. Choose a roadside (or a retention pond collecting runoff water from a roadway like for those data) with roadtraffic monitoring, 2. Regularly collect macrolitter > 1 cm along the same portion of road (or in the same retention pond), 3. Classified macrolitter collected according to TSG-ML/OSPAR classification and weighs dry masses by item category, 4. Report data relative to roadtraffic and other environmental parameters.