Beach litter - Median number of cigarette related items normalized per 100m & to 1 survey - UNEP_MARLIN only - EU-MSFD monitoring 2001/2023 v2025

This visualization product displays the cigarette related items abundance of marine macro-litter (> 2.5cm) per beach per year from Marine Strategy Framework Directive (MSFD) monitoring surveys without UNEP-MARLIN data.

EMODnet Chemistry included the collection of marine litter in its 3rd phase. Since the beginning of 2018, data of beach litter have been gathered and processed in the EMODnet Chemistry Marine Litter Database (MLDB).

The harmonization of all the data has been the most challenging task considering the heterogeneity of the data sources, sampling protocols and reference lists used on a European scale.

Preliminary processings were necessary to harmonize all the data:

- Exclusion of OSPAR 1000 protocol: in order to follow the approach of OSPAR that it is not including these data anymore in the monitoring;

- Selection of MSFD surveys only (exclusion of other monitoring, cleaning and research operations);

- Exclusion of beaches without coordinates;

- Selection of cigarette related items only. The list of selected items is attached to this metadata. This list was created using EU Marine Beach Litter Baselines, the European Threshold Value for Macro Litter on Coastlines and the Joint list of litter categories for marine macro-litter monitoring from JRC (these three documents are attached to this metadata);

- Selection of surveys referring to the UNEP-MARLIN list: the UNEP-MARLIN protocol differs from the other types of monitoring in that cigarette butts are surveyed in a 10m square. To avoid comparing abundances from very different protocols, the choice has been made to distinguish in two maps the cigarette related items results associated with the UNEP-MARLIN list from the others;

- Normalization of survey lengths to 100m & 1 survey / year: in some case, the survey length was not exactly 100m, so in order to be able to compare the abundance of litter from different beaches a normalization is applied using this formula:

Number of cigarette related items of the survey (normalized by 100 m) = Number of cigarette related items of the survey x (100 / survey length)

Then, this normalized number of cigarette related items is summed to obtain the total normalized number of cigarette related items for each survey. Finally, the median abundance of cigarette related items for each beach and year is calculated from these normalized abundances of cigarette related items per survey.

Sometimes the survey length was null or equal to 0. Assuming that the MSFD protocol has been applied, the length has been set at 100m in these cases.

Percentiles 50, 75, 95 & 99 have been calculated taking into account cigarette related items from MSFD monitoring data (excluding UNEP-MARLIN protocol) for all years.

More information is available in the attached documents.

Warning: the absence of data on the map does not necessarily mean that they do not exist, but that no information has been entered in the Marine Litter Database for this area.

本可视化产品展示了不含联合国环境规划署海洋垃圾监测与信息网络（UNEP-MARLIN）数据的海洋战略框架指令（MSFD）监测调查中，每处海滩每年的海洋大型垃圾（marine macro-litter，＞2.5cm）中与香烟相关物品的丰度。

欧洲海洋观测与数据网络化学分部（EMODnet Chemistry）在其第三阶段纳入了海洋垃圾采集工作。自2018年初起，海滩垃圾数据已在欧洲海洋观测与数据网络化学分部海洋垃圾数据库（MLDB）中完成收集与处理。

考虑到欧洲范围内数据源、采样方案及参考清单存在异质性，对所有数据进行统一协调是本次工作中最具挑战性的任务。

为完成所有数据的统一协调，需开展以下初步处理工作：
- 排除奥斯陆巴黎委员会（OSPAR）1000号采样方案：以遵循奥斯陆巴黎委员会不再将此类数据纳入监测的相关要求；
- 仅选取海洋战略框架指令（MSFD）监测调查数据，排除其他监测、清理及研究作业获取的数据；
- 排除未提供坐标信息的海滩；
- 仅选取与香烟相关的垃圾品类。本次选取的品类清单附于本元数据中，该清单依据《欧盟海洋海滩垃圾基线》《沿海大型海洋垃圾阈值》及欧盟联合研究中心（JRC）制定的《海洋大型垃圾监测垃圾类别联合清单》编制，上述三份文件均附于本元数据内；
- 选取采用联合国环境规划署海洋垃圾监测与信息网络（UNEP-MARLIN）清单的调查：该方案与其他监测方案的区别在于，其在10平方米样方内开展烟蒂调查。为避免对比不同采样方案得到的垃圾丰度数据，本次选择将采用该清单的香烟相关物品监测结果与其他结果分两张可视化地图展示；
- 将调查样带长度归一化至100米，且每年仅统计1次调查：部分调查的样带长度并非恰好100米，为实现不同海滩垃圾丰度的可比分析，采用如下公式开展归一化处理：
归一化至100米的调查香烟相关物品数量 = 调查实际统计的香烟相关物品数量 × (100 / 调查样带长度)
随后，将该归一化后的香烟相关物品数量求和，得到单次调查的总归一化香烟相关物品数量。最终，基于各次调查得到的归一化香烟相关物品丰度，计算每处海滩每年的香烟相关物品丰度中位数。

若调查样带长度为空或为0，在假设已遵循海洋战略框架指令（MSFD）采样方案的前提下，将该长度设置为100米。

针对所有年份的海洋战略框架指令（MSFD）监测数据（不含联合国环境规划署海洋垃圾监测与信息网络（UNEP-MARLIN）方案数据），已计算得到50、75、95及99百分位数。

更多详细信息可参阅附件文件。

警告：地图上未展示数据并不代表该区域不存在相关垃圾数据，仅表示该区域尚未有数据录入海洋垃圾数据库（MLDB）。