Dazed, confused, and then hungry: pesticides alter predator-prey interactions of estuarine organisms

Effects of contaminants and flooding on the physiology of harvested estuarine decapod crustaceans: A global review and meta-analysis

Contaminants are transported into estuaries during rainfall events, impacting the physiology of harvested species, and thereby threatening fisheries sustainability. Decapods are among the most economically important groups harvested from estuaries, but are at high risk of contaminant exposure. We conducted a systematic review and meta-analysis evaluating the physiological responses of harvested estuarine decapods to contaminants and flooding. A total of 138 research articles were identified, with global research efforts corresponding to the geographic distribution of crustacean harvesting. From these studies, 305 acute toxicity values for metals, polcyclic aromatic hydrocarbons (PAHs) and pesticide chemical classes were extracted and 341 sublethal effect sizes (log-response ratios; LnRRs) calculated using 91 physiological measures across seven response categories. At sublethal environmentally relevant concentrations, exposure to various metals, pesticide chemical classes and PAHs consistently elicited negative effects on decapod physiology (LnRR range: -0.67 to -0.07). Key physiological processes impacted by contaminant exposure included nutritional condition, osmoregulation, oxidative stress defences, acetylcholinesterase activity, metabolism and growth (LnRR range: -0.73 to -0.10), with a general trend for greater effects later in ontogeny. With new agricultural and industrial chemicals continually being marketed, our meta-analysis highlights the need for regulatory testing on harvested species prior to registration for use in catchment areas. Under future climatic variability, harvested estuarine decapods may be increasingly exposed to contaminants, with implications for fisheries and global food security.

Unexpected air pollutants with potential human health hazards: Nitrification inhibitors, biocides, and persistent organic substances

To better understand the influence of land use and meteorological parameters on air pollutants, we deployed passive air samplers in 15 regions with different land use in eastern Austria. The samplers consisted of polyurethane PUF and polyester PEF filter matrices, which were analyzed for 566 substances by gas-chromatography/mass-spectrometry. In a previous article, we highlighted a widespread contamination of ambient air with pesticides that depends on the surrounding land use and meteorological parameters. Here we report that, in addition to agricultural pesticides, eight other substances were frequently detected in ambient air: Nitrapyrin, a nitrification inhibitor used to increase nitrogen use efficiency of fertilizers and banned in Austria since 1993; biocides against insects (DEET and transfluthrin) used mainly outside agriculture; piperonyl butoxide (PBO), a synergist mixed into pesticide formulations; and four industrially used polychlorinated biphenyls (PCBs), long banned worldwide. Concentrations of the detected substances were positively related to air temperature, but only slightly related to agricultural land use in the sampler's vicinity. The city center showed the highest concentrations of biocides, PCBs and PBO, but also medium concentrations of nitrapyrin. Four sites had no air contamination with these substances; including two national parks dominated by grassland or forest, but also two sites with mixed land use. The potential human toxicity of the detected substances based on globally harmonized hazard classifications was high: seven substances had specific organ toxicity, six were cancerogenic, and two were acutely toxic; however, several substances had incomplete information of hazard profiles. Moreover, all substances were acutely and chronically toxic to aquatic life. We recommend that substances of different origins be included in the air pollution monitoring portfolio to comprehensively assess the potential hazards to humans and the environment.

Newer characters, same story: neonicotinoid insecticides disrupt food webs through direct and indirect effects

During the Green Revolution, older classes of insecticides contributed to biodiversity loss by decreasing insect populations and bioaccumulating across food webs. Introduction of Integrated Pest Management (IPM) improved stewardship of insecticides and promised fewer non-target effects. IPM adoption has waned in recent decades, and popularity of newer classes of insecticides, like the neonicotinoids, has surged, posing new and unique threats to insect populations. In this review, we first address how older classes of insecticides can affect trophic interactions, and then consider the influence of neonicotinoids on food webs and the role they may be playing in insect declines. We conclude by discussing challenges posed by current use patterns of neonicotinoids and how their risk can be addressed.