Tracking POPs in Global Air from the First 10 Years of the GAPS Network (2005 to 2014)

The Global Atmospheric Passive Sampling
(GAPS) network, initiated
in 2005 across 55 global sites, supports the global monitoring plan
(GMP) of the Stockholm Convention on Persistent Organic Pollutants
(POPs) by providing information on POP concentrations in air on a
global scale. These data inform assessments of the long-range transport
potential of POPs and the effectiveness evaluation of chemical regulation
efforts, by observing changes in concentrations over time. Currently,
measurements spanning 5–10 sampling years are available for
40 sites from the GAPS Network. This study was the first time that
POP concentrations in air were reported on a global scale for an extended
time period and the first to evaluate worldwide trends with an internally
consistent sample set. For consistency between sampling years, site-
and sample specific sampling rates were calculated with a new, public
online model, which accounts for the effects of wind speed variability.
Concentrations for legacy POPs in air between 2005 and 2014 show different
trends for different organochlorine pesticides (OCPs) and polychlorinated
biphenyls (PCBs). The POPs discussed in this study were chosen due
to being the most frequently detected, with detection at the majority
of sites. PCB, endosulfan, and hexachlorocyclohexane (HCH) concentrations
in air are decreasing at most sites. The global trends reflect global
sources and recycling of HCH, ongoing emissions from old stockpiles
for PCBs, and recent use restrictions for endosulfan. These chlorinated
OCPs continue to present exposure threat to humans and ecosystems
worldwide. Concentrations of other OCPs, such as chlordanes, heptachlor
and dieldrin, are steady and/or declining slowly at the majority of
sites, reflecting a transition from primary to secondary sources (i.e.,
re-emission from reservoirs where these POPs have accumulated historically)
which now control ambient air burdens.

全球大气被动采样（GAPS）网络，始于2005年，覆盖全球55个站点，通过提供全球范围内空气中持久性有机污染物（POPs）浓度的信息，支持《斯德哥尔摩公约》关于持久性有机污染物的全球监测计划（GMP）。这些数据有助于评估POPs的长距离传输潜力以及化学监管措施的有效性评估，通过观察浓度随时间的变化。目前，GAPS网络中的40个站点提供了5至10年的测量数据。本研究首次在全球范围内对长时间段内空气中的POPs浓度进行了报道，并首次使用内部一致的样本集评估了全球趋势。为了保持采样年份之间的一致性，利用一个新的公开在线模型计算了站点和样本特定的采样率，该模型考虑了风速变化的影响。2005年至2014年间，空气中的传统POPs浓度（如有机氯农药（OCPs）和多氯联苯（PCBs））在不同站点显示出不同的趋势。本研究中讨论的POPs因其频繁检测以及在多数站点均有检出而被选中。在大多数站点，空气中的PCB、艾氏剂和六氯环己烷（HCH）浓度呈下降趋势。全球趋势反映了HCH的全球来源和回收、PCBs的老库存持续排放以及最近对艾氏剂的限制使用。这些氯化OCPs继续对全球人类和生态系统构成暴露威胁。其他OCPs（如六氯苯、七氯和滴滴涕）的浓度在多数站点稳定且/或缓慢下降，反映了从初级来源（即，这些POPs在历史上积累的库中重新排放）向次级来源的过渡，这些次级来源现在控制着环境空气负荷。