Common use of Ingestion Clause in Contracts

Ingestion. Ingestion is perhaps the main concern regarding plastics and waterbirds, because it can affect large proportions of some populations, and has the potential for both physical and chemical impacts (▇▇▇▇▇▇▇ 2009, ▇▇▇▇ et al. 2015, ▇▇▇▇ 2016). Ingestion can be direct (primary ingestion) or indirect (secondary ingestion via contaminated prey). The size of plastic items relative to prey species probably offers the best way to differentiate these two ingestion routes. Plastic items ingested directly tend to be roughly similar in size to prey items, whereas secondary ingested items tend to be much smaller than prey items. However, direct ingestion can result from deliberate ingestion, when plastic items are mistaken for prey items, or accidental ingestion, when plastics are consumed passively along with prey items (▇▇▇▇ 2016). The latter category might include items appreciably smaller than the main prey species, and thus be confused with secondary ingestion. Dabbling ducks probably ingest most plastic accidentally (▇.▇. ▇▇▇▇▇▇▇ et al. 2015, ▇▇▇-▇▇▇▇▇▇▇ et al. 2017, ▇▇▇▇▇▇▇▇ & ▇▇▇▇ 2018). It also can be hard to distinguish ingestion from entanglement when live birds are seen trailing fishing line – this could result from ingestion of a hook or entanglement in a hook or line. Ingestion of a fishing hook and line (e.g. Hong et al. 2013) is perhaps better treated as bycatch than ingestion, although birds can digest fishing hooks, leaving only the line in their stomachs, and thus be indistinguishable from ingestion (▇▇▇▇ 2015b). Most plastic ingestion by birds – at least at the size range of items that are readily detected in their stomach contents – appears to be ingested directly. Secondary ingestion has been inferred for terns (▇▇▇▇ & Cormons 1974) and ▇▇▇▇▇ (▇▇▇▇ & ▇▇▇▇▇▇ 1988, ▇▇▇▇▇▇ et al. 2016), based on the presence of plastic in regurgitated pellets, and may be regular in piscivorous species (e.g. gannets, cormorants, divers, herons, auks, etc.) given the frequent occurrence of plastic recorded in both marine and freshwater fish, at least in Europe (▇.▇. ▇▇▇▇▇▇▇ et al. 2014, ▇▇▇▇▇ et al. 2015, ▇▇▇▇ & ▇▇▇▇▇▇▇▇ 2015, ▇▇▇▇ et al. 2015, Rummel et al. 2016, ▇▇▇▇▇▇▇ et al. 2017, ▇▇▇▇▇▇ et al. 2017, ▇▇▇▇▇ et al. 2018, but see also ▇▇▇▇▇▇▇ et al. 2017). However, most plastics ingested by fish that are small enough to be eaten by birds are likely to be small enough to be excreted rapidly by birds. Skua pellets containing ingested plastics mainly come from eating other seabirds (▇.▇. ▇▇▇▇ 2008, ▇▇▇▇▇▇ et al. 2016). The likelihood of accidental ingestion may be increased when plastic is associated with prey species. For example, (Phoebastria) albatrosses in the North Pacific Ocean often eat flying fish egg masses, which stick to floating debris (▇▇▇▇▇▇ et al. 1981). Gulls scavenging at refuse dumps probably consume plastic bags, food wrappings and other debris (e.g. aluminium foil) that are associated with human food wastes (cf. ▇▇▇▇▇▇▇▇▇ et al. 2017). However, the evidence from petrels (Procellariiformes), the bird order that most often contain ingested plastic, suggests that most plastic items found in their gizzards are ingested deliberately, as a result of confusion with prey items (▇▇▇▇ 2016). This is supported by the apparent selection of conspicuously-coloured plastic items, when compared to the incidence of plastic items collected at sea (e.g. Day et al. 1985, ▇▇▇▇ 1987a). ▇▇▇▇▇▇▇ are known to select for red items at sea (▇▇▇▇▇▇ 1979), and it is likely that most foraging decisions are largely visual. ▇▇▇▇▇▇ et al. (2016) argued that scent might play a role in plastic ingestion by ▇▇▇▇▇▇▇, but this has been questioned (Dell’Ariccia et al. 2016).

Ingestion. Ingestion is perhaps the main concern regarding plastics and waterbirds, because it can affect large proportions of some populations, and has the potential for both physical and chemical impacts (▇▇▇▇▇▇▇ 2009, ▇▇▇▇ et al. 2015, ▇▇▇▇ 2016). Ingestion can be direct (primary ingestion) or indirect (secondary ingestion via contaminated prey). The size of plastic items relative to prey species probably offers the best way to differentiate these two ingestion routes. Plastic items ingested directly tend to be roughly similar in size to prey items, whereas secondary ingested items tend to be much smaller than prey items. However, direct ingestion can result from deliberate ingestion, when plastic items are mistaken for prey items, or accidental ingestion, when plastics are consumed passively along with prey items (▇▇▇▇ 2016). The latter category might include items appreciably smaller than the main prey species, and thus be confused with secondary ingestion. Dabbling ducks probably ingest most plastic accidentally (▇.▇. ▇▇▇▇▇▇▇ et al. 2015, ▇▇▇-▇▇▇▇▇▇▇ et al. 2017, ▇▇▇▇▇▇▇▇ & ▇▇▇▇ 2018). It also can be hard to distinguish ingestion from entanglement when live birds are seen trailing fishing line – this could result from ingestion of a hook or entanglement in a hook or line. Ingestion of a fishing hook and line (e.g. Hong et al. 2013) is perhaps better treated as bycatch than ingestion, although birds can digest fishing hooks, leaving only the line in their stomachs, and thus be indistinguishable from ingestion (▇▇▇▇ 2015b). Most plastic ingestion by birds – at least at the size range of items that are readily detected in their stomach contents – appears to be ingested directly. Secondary ingestion has been inferred for terns (▇▇▇▇ & Cormons 1974) and ▇▇▇▇▇ (▇▇▇▇ & ▇▇▇▇▇▇ 1988, ▇▇▇▇▇▇ et al. 2016), based on the presence of plastic in regurgitated pellets, and may be regular in piscivorous species (e.g. gannets, cormorants, divers, herons, auks, etc.) given the frequent occurrence of plastic recorded in both marine and freshwater fish, at least in Europe (▇.▇. ▇▇▇▇▇▇▇ et al. 2014, ▇▇▇▇▇ et al. 2015, ▇▇▇▇ & ▇▇▇▇▇▇▇▇ 2015, ▇▇▇▇ et al. 2015, Rummel ▇▇▇▇▇▇ et al. 2016, ▇▇▇▇▇▇▇ et al. 2017, ▇▇▇▇▇▇ et al. 2017, ▇▇▇▇▇ et al. 2018, but see also ▇▇▇▇▇▇▇ et al. 2017). However, most plastics ingested by fish that are small enough to be eaten by birds are likely to be small enough to be excreted rapidly by birds. Skua pellets containing ingested plastics mainly come from eating other seabirds (▇.▇. ▇▇▇▇ 2008, ▇▇▇▇▇▇ et al. 2016). The likelihood of accidental ingestion may be increased when plastic is associated with prey species. For example, (Phoebastria) albatrosses in the North Pacific Ocean often eat flying fish egg masses, which stick to floating debris (▇▇▇▇▇▇ et al. 1981). Gulls scavenging at refuse dumps probably consume plastic bags, food wrappings and other debris (e.g. aluminium foil) that are associated with human food wastes (cf. ▇▇▇▇▇▇▇▇▇ et al. 2017). However, the evidence from petrels (Procellariiformes), the bird order that most often contain ingested plastic, suggests that most plastic items found in their gizzards are ingested deliberately, as a result of confusion with prey items (▇▇▇▇ 2016). This is supported by the apparent selection of conspicuously-coloured plastic items, when compared to the incidence of plastic items collected at sea (e.g. Day et al. 1985, ▇▇▇▇ 1987a). ▇▇▇▇▇▇▇ are known to select for red items at sea (▇▇▇▇▇▇ 1979), and it is likely that most foraging decisions are largely visual. ▇▇▇▇▇▇ et al. (2016) argued that scent might play a role in plastic ingestion by ▇▇▇▇▇▇▇, but this has been questioned (Dell’Ariccia et al. 2016).